HD render fixes (#35-#39, #41) and replay time of day (#57) (fork patch 25); radar scan cycles with ageing tracks (#46), damage to individual system parts (#50), long-lasting fires (#52)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.gitignore

@@ -5,3 +5,4 @@ airdef-mod/target/
 __pycache__/
 /out/
 .DS_Store
+run-home-bench/

airdef-mod/examples/sim_run/harness.rs

@@ -18,6 +18,13 @@ pub enum Terrain {
     Hills { base: i32, amp: f64, period: f64 },
 }
 
+/// The land as blocks: solid at and below the column's height (what the game would answer `render.sections` with).
+impl airdef::sim::world::WorldSource for Terrain {
+    fn solid(&self, x: i32, y: i32, z: i32) -> Option<bool> {
+        Some(y < self.height(x, z))
+    }
+}
+
 impl Terrain {
     pub fn height(self, x: i32, z: i32) -> i32 {
         match self {
@@ -98,6 +105,9 @@ pub struct Report {
     /// Missiles fired by air defence (sum of the systems' `fired`).
     pub fired: u32,
     pub ground_queries: u64,
+    /// The block cache's counters (issue #43) and the drones that struck the land (issue #42).
+    pub world: String,
+    pub crashes: u32,
     pub ground_batches: u64,
     pub tick_p50: Duration,
     pub tick_p95: Duration,
@@ -163,6 +173,8 @@ pub fn run(sc: &Scenario) -> Report {
         let t = Instant::now();
         sim.step(&mut ground, None, &mut out);
         let wanted = ground.take_wanted();
+        let sections = ground.world.take_wanted(now);
+        ground.world.serve(&sc.terrain, sections, now);
         let dt = t.elapsed();
         times.push(dt);
         if planning {
@@ -212,6 +224,8 @@ pub fn run(sc: &Scenario) -> Report {
     r.hits = sim.hits;
     r.fired = sim.sams.iter().map(|s| s.fired).sum();
     r.raids_ordered = ordered.iter().filter(|o| **o).count();
+    r.world = ground.world.text();
+    r.crashes = sim.crashes;
     r.raids_ended = ended.iter().filter(|o| **o).count();
     r.all_ended = r.raids_ended == sc.raids.len();
     r.tick_total = times.iter().sum();
@@ -253,7 +267,8 @@ impl Report {
              planning: {pl:.1} ms over {pt} ticks\n\
              ground queries: {gq} in {gb} batches\n\
              non-finite positions: {nan}\n\
-             stuck trucks: {stuck:?} (busy truck-ticks {busy})\n",
+             stuck trucks: {stuck:?} (busy truck-ticks {busy})\n\
+             crashes into the land: {crashes}; {world}\n",
             name = self.name,
             seed = self.seed,
             units = self.units,
@@ -276,6 +291,8 @@ impl Report {
             nan = self.nan_positions,
             stuck = self.stuck_trucks,
             busy = self.truck_busy_ticks,
+            crashes = self.crashes,
+            world = self.world,
         )
     }
     pub fn json(&self) -> String {

airdef-mod/src/lib.rs

@@ -330,6 +330,16 @@ impl AirDef {
             let id = 0x6100_0000 | (b.id & 0x00ff_ffff);
             add(id, b.at + DVec3::Y * size as f64 * 0.5, (1.0, 0.58, 0.25), size * size * 18.0 * (glow + flash), size * 14.0);
         }
+        // Fires burn on for minutes: a flickering, wide glow that dies down with the flames.
+        for f in &self.sim.fires.list {
+            let (fl, sm) = f.level(tick);
+            if f.quiet {
+                continue;
+            }
+            let glow = fl.max(0.12 * sm * (1.0 - (tick.saturating_sub(f.start)) as f32 / f.life as f32));
+            let id = 0x6200_0000 | (f.id & 0x00ff_ffff);
+            add(id, f.at + DVec3::Y * 1.2, (1.0, 0.5, 0.17), 70.0 * f.size * glow * flicker(f.id), 20.0 + 10.0 * f.size);
+        }
         for s in &self.sim.sams {
             if !s.alive() && s.burning() {
                 add(s.id + 15, s.pos + DVec3::Y * 1.5, (1.0, 0.5, 0.18), 80.0 * flicker(s.id), 30.0);
@@ -541,8 +551,11 @@ impl AirDef {
             } else {
                 (s.health, s.cargo, s.missiles, s.bursts, s.empty, s.reloading)
             };
+            // The parts' states (sensor, mount, launcher, gun, tracks, comms) close the line; older saves lack them.
+            let comps = if fresh { new.comps } else { s.comps };
+            let parts = comps.0.iter().map(|v| format!("{v:.3}")).collect::<Vec<_>>().join(" ");
             text += &format!(
-                "sam {} {} {} {} {} {} {} {} {} {} {} {} {dest}\n",
+                "sam {} {} {} {} {} {} {} {} {} {} {} {} {dest} {parts}\n",
                 s.kind.key(),
                 s.pos.x,
                 s.pos.y,
@@ -629,6 +642,13 @@ impl AirDef {
                             (Some(x), Some(y), Some(z)) => Some(DVec3::new(x, y, z)),
                             _ => None,
                         };
+                        // The parts: absent in older saves, which load with every part whole.
+                        for (k, v) in sam.comps.0.iter_mut().enumerate() {
+                            if let Some(c) = num(16 + k) {
+                                *v = c.clamp(0.0, 1.0);
+                            }
+                        }
+                        sam.fit_cells();
                         self.sim.sams.push(sam);
                         if let Some(to) = dest {
                             let i = self.sim.sams.len() - 1;
@@ -765,6 +785,7 @@ impl AirDef {
 
     fn stop_replay(&mut self) {
         self.replay = None;
+        render::set_time_override(None);
         input::claim_wheel(false);
         render::set_hud(&[]);
         render::set_views(&[]);
@@ -959,7 +980,7 @@ impl AirDef {
     }
 }
 
-const HELP: &str = "/airdef menu | monitor | grid | replay [map|full|reel|stop] | scenario save|load|list|delete | why [номер] | raid | repair | import | ew on|off | flare | move <номер> | target here | give | deploy <комплекс> | wave <тип|mix> [кол-во] [дальность] | clear | targets clear | damage on|off | shader on|off|hd | hold on|off | roles [комплекс классы] | stats";
+const HELP: &str = "/airdef menu | monitor | grid | replay [map|full|reel|stop] | scenario save|load|list|delete | why [номер] | raid | repair | import | ew on|off | flare | move <номер> | target here | give | deploy <комплекс> | wave <тип|mix> [кол-во] [дальность] | clear | targets clear | damage on|off | truth on|off | shader on|off|hd | hold on|off | roles [комплекс классы] | stats";
 
 impl Mod for AirDef {
     fn init() -> Result<(Self, Registration), String> {
@@ -1061,14 +1082,38 @@ impl Mod for AirDef {
         }
         let now = self.sim.tick;
         self.ground.answer(render::ground(), now);
+        // The blocks themselves (issues #42, #43): what changed, and the sections asked for last tick.
+        let changes = render::world_changes();
+        self.ground.world.changed(changes.epoch, changes.overflow, &changes.sections);
+        let sections = render::sections()
+            .into_iter()
+            .map(|s| sim::world::SectionAnswer {
+                sec: (s.x, s.y, s.z),
+                fill: match s.fill {
+                    render::SectionFill::Unknown => sim::world::Fill::Unknown,
+                    render::SectionFill::Empty => sim::world::Fill::Empty,
+                    render::SectionFill::Full => sim::world::Fill::Full,
+                    render::SectionFill::Mixed => match <[u8; 512]>::try_from(s.bits) {
+                        Ok(bits) => sim::world::Fill::Mixed(Box::new(bits)),
+                        Err(_) => sim::world::Fill::Unknown,
+                    },
+                },
+            })
+            .collect();
+        self.ground.world.answer(sections, now);
         let mut out = Out::default();
         self.listener = DVec3::new(p.x, p.y + 1.6, p.z);
         self.sim.night = game::get_clock().is_some_and(|c| (13000..23000).contains(&(c.day_time % 24000)));
+        self.sim.day_time = game::get_clock().map(|c| c.day_time);
         self.sim.step(&mut self.ground, Some(DVec3::new(p.x, p.y, p.z)), &mut out);
         let wanted = self.ground.take_wanted();
         if !wanted.is_empty() {
             render::query_ground(&wanted);
         }
+        let sections = self.ground.world.take_wanted(now);
+        if !sections.is_empty() {
+            render::query_sections(render::Policy::Collision, &sections);
+        }
         if let Some(mut r) = self.replay.take() {
             r.tick(&self.sim, self.listener, &mut out);
             if r.done {
@@ -1085,6 +1130,8 @@ impl Mod for AirDef {
             let size = render::gui_size();
             render::set_hud(&r.hud(&self.sim, size));
             render::set_views(&r.views(size));
+            // The sky of the raid, not of now (None for a raid whose clock was unknown).
+            render::set_time_override(r.day_time(&self.sim));
             self.monitor_shown = true;
         } else if self.grid {
             let stale = self.grid_ids.iter().any(|id| !self.sim.sams.iter().any(|s| s.id == *id));
@@ -1123,7 +1170,8 @@ impl Mod for AirDef {
                 let at = s.dest.unwrap_or(s.pos);
                 let place = (at.x * 10.0) as i64 as u64 ^ ((at.z * 10.0) as i64 as u64).rotate_left(21) ^ (if s.dest.is_some() { 0 } else { (s.heading * 100.0) as i64 as u64 }).rotate_left(42);
                 let ammo = u64::from(s.missiles) | u64::from(s.bursts) << 16 | u64::from(s.cargo) << 32 | u64::from(s.empty) << 48 | u64::from(s.reloading > 0) << 49;
-                ((s.health * 1000.0) as u64).wrapping_mul(1_000_003) ^ place ^ ammo.rotate_left(7)
+                let parts = s.comps.0.iter().fold(0u64, |a, v| a.wrapping_mul(131).wrapping_add((v * 100.0) as u64));
+                ((s.health * 1000.0) as u64).wrapping_mul(1_000_003) ^ place ^ ammo.rotate_left(7) ^ parts.rotate_left(13)
             })
             .chain(self.sim.target_health.iter().map(|h| (h * 10.0) as u64))
             .fold(self.sim.sams.len() as u64, |a, h| a.wrapping_mul(31).wrapping_add(h));
@@ -1386,7 +1434,7 @@ impl Mod for AirDef {
             ["repair"] => {
                 let n = self.sim.repair();
                 self.dirty = true;
-                Some(format!("Отремонтировано комплексов: {n}; объекты восстановлены"))
+                Some(format!("Отремонтировано комплексов: {n} (корпус и все узлы: РЛС, привод, пусковая, орудие, ходовая, связь); объекты восстановлены"))
             }
             ["clear"] => {
                 self.sim.clear();
@@ -1405,6 +1453,10 @@ impl Mod for AirDef {
                 self.dirty = true;
                 Some("Цели убраны".to_string())
             }
+            ["truth", v @ ("on" | "off")] => {
+                self.sim.truth = *v == "on";
+                Some(format!("Истинные данные на радаре: {} (боевую логику не меняют)", if self.sim.truth { "вкл" } else { "выкл" }))
+            }
             ["damage", v @ ("on" | "off")] => {
                 self.sim.damage = *v == "on";
                 self.dirty = true;
@@ -1451,12 +1503,14 @@ impl Mod for AirDef {
                 Some(format!("Эффекты: {}", match *v { "off" => "выкл", "hd" => "HD", _ => "обычные" }))
             }
             ["stats"] => Some(format!(
-                "В воздухе: {}, ракет: {}, ПВО: {}, сбито: {}, поражений: {}",
+                "В воздухе: {}, ракет: {}, ПВО: {}, сбито: {}, поражений: {}, разбились о препятствия: {}; {}",
                 self.sim.drones.iter().filter(|d| d.alive()).count(),
                 self.sim.missiles.len(),
                 self.sim.sams.len(),
                 self.sim.kills,
-                self.sim.hits
+                self.sim.hits,
+                self.sim.crashes,
+                self.ground.world.text()
             )),
             _ => return Err(HELP.to_string()),
         };

airdef-mod/src/monitor.rs

@@ -119,8 +119,10 @@ fn cell(sim: &Sim, index: usize, x: f32, y: f32, w: f32, h: f32, s: &mut Vec<Sha
         _ => spec.sensor,
     };
     let scale = if reach > 0.0 { rr as f64 / (reach * 1.25) } else { 0.0 };
-    let sweep = (tick as f32 * 0.12 + index as f32) % std::f32::consts::TAU;
-    for k in 0..6 {
+    // The beam is the radar's real one: targets are measured as it passes them.
+    let sweep = sam.beam() as f32;
+    let radar_up = sam.radar_up();
+    for k in 0..if radar_up { 6 } else { 0 } {
         let a1 = sweep - k as f32 * 0.09;
         let a0 = a1 - 0.09;
         let p = |a: f32| (rx + a.sin() * rr, ry - a.cos() * rr);
@@ -129,8 +131,14 @@ fn cell(sim: &Sim, index: usize, x: f32, y: f32, w: f32, h: f32, s: &mut Vec<Sha
     let target = sim.watched(sam);
     let mut seen = 0;
     // Only what its own radar holds.
-    for d in sim.drones.iter().filter(|d| d.alive() && sam.seen.contains(&d.id)) {
-        let rel = d.pos - sam.pos;
+    for (d, tr) in sim.drones.iter().filter(|d| d.alive()).filter_map(|d| sam.track(d.id).map(|t| (d, t))) {
+        // Where the system believes it is: the last measurement carried on; a forecast is drawn hollow.
+        let est = tr.est(tick);
+        if sim.truth {
+            let r = d.pos - sam.pos;
+            s.push(fill(rx + r.x as f32 * scale as f32 - 0.5, ry + r.z as f32 * scale as f32 - 0.5, 1.0, 1.0, 0xFFFFFFFF));
+        }
+        let rel = est - sam.pos;
         let flat = (rel.x * rel.x + rel.z * rel.z).sqrt();
         if reach <= 0.0 || flat > reach * 1.25 {
             continue;
@@ -146,10 +154,24 @@ fn cell(sim: &Sim, index: usize, x: f32, y: f32, w: f32, h: f32, s: &mut Vec<Sha
         } else {
             0xFF808080
         };
-        s.push(fill(bx - 1.5, by - 1.5, 3.0, 3.0, color));
+        if tr.forecast(tick) {
+            s.push(fill(bx - 1.5, by - 1.5, 3.0, 1.0, color));
+            s.push(fill(bx - 1.5, by + 0.5, 3.0, 1.0, color));
+            s.push(fill(bx - 1.5, by - 0.5, 1.0, 1.0, color));
+            s.push(fill(bx + 0.5, by - 0.5, 1.0, 1.0, color));
+        } else {
+            s.push(fill(bx - 1.5, by - 1.5, 3.0, 3.0, color));
+        }
     }
     s.push(fill(rx - 1.5, ry - 1.5, 3.0, 3.0, 0xFF40A0FF));
-    s.push(text(fit(format!("РЛС {} · {}", distance(reach), seen), rr * 2.0 + 4.0), x + 4.0, y + h - 10.0, 0xFF80FF90));
+    let radar_text = if spec.sensor <= 0.0 {
+        format!("сеть · {seen}")
+    } else if radar_up {
+        format!("РЛС {} · {}", distance(reach), seen)
+    } else {
+        "РЛС ОТКАЗ".to_string()
+    };
+    s.push(text(fit(radar_text, rr * 2.0 + 4.0), x + 4.0, y + h - 10.0, if spec.sensor > 0.0 && !radar_up { 0xFFFF5040 } else { 0xFF80FF90 }));
 
     // Its health under the radar: a bar, red when it is low.
     if sam.alive() && sam.health < 1.0 {
@@ -184,6 +206,11 @@ fn cell(sim: &Sim, index: usize, x: f32, y: f32, w: f32, h: f32, s: &mut Vec<Sha
         (false, false) => 0,
     };
     s.push(Shape::View(ViewShape { view: sam.id, rect: Rect { x: cx, y: cy, w: cw, h: ch }, mode }));
+    // Worn or failed parts, over the picture: orange, red when one has failed.
+    if !sam.comps.whole() {
+        let failed = crate::sim::Part::ALL.iter().any(|p| sam.part_state(*p) == crate::sim::PartState::Failed);
+        s.push(text(fit(sam.parts_text(), cw * 0.55), cx + 3.0, cy + 3.0, if failed { 0xFFFF4040 } else { 0xFFFFB030 }));
+    }
     // Crosshair.
     s.push(fill(cx + cw / 2.0 - 0.5, cy + 3.0, 1.0, ch * 0.18, 0x90FFFFFF));
     s.push(fill(cx + cw / 2.0 - 0.5, cy + ch * 0.82 - 3.0, 1.0, ch * 0.18, 0x90FFFFFF));
@@ -200,12 +227,22 @@ fn cell(sim: &Sim, index: usize, x: f32, y: f32, w: f32, h: f32, s: &mut Vec<Sha
             if !t.alive() || sim.showing_kill(sam) {
                 s.push(text("ПОРАЖЕНА", cx + cw / 2.0 - 24.0, cy + ch / 2.0 + bh / 2.0 + 2.0, 0xFF60FF60));
             }
-            let rel = t.pos - sam.pos;
+            // The system knows the target by its track: the forecast of the last measurement.
+            let track = sam.track(t.id);
+            let at = track.map_or(t.pos, |tr| tr.est(tick));
+            let rel = at - sam.pos;
             let bearing = (heading_of(rel).to_degrees() + 180.0).rem_euclid(360.0);
             if ch > 50.0 {
                 s.push(text(fit(t.kind.spec().name.into(), cw - 6.0), cx + 3.0, cy + ch - 20.0, 0xFFFFFFFF));
             }
-            let mut info = format!("{} в{:.0} {:.0}км/ч", distance(rel.length()), t.pos.y - sam.pos.y, t.vel.length() * 72.0);
+            let mut info = format!("{} в{:.0} {:.0}км/ч", distance(rel.length()), at.y - sam.pos.y, t.vel.length() * 72.0);
+            if let Some(tr) = track {
+                if tr.forecast(tick) {
+                    info += &format!(" прогноз {:.1}с", tr.age(tick) as f64 / 20.0);
+                } else if cw > 200.0 {
+                    info += &format!(" {}", tr.ident().name());
+                }
+            }
             if cw > 220.0 {
                 info += &format!(" П{bearing:03.0}");
             }

airdef-mod/src/radar.rs

@@ -108,24 +108,40 @@ pub fn draw(sim: &Sim, player: DVec3, yaw: f32) -> Vec<Shape> {
         }
     }
     let mut far = 0;
-    // The air picture is what the systems' radars hold; with none deployed, everything.
+    // The air picture is what the systems' radars hold, as they last measured it (a track older than a second
+    // is a forecast, dimmer); with no system deployed, everything as it is.
     let any = !sim.sams.is_empty();
-    for d in sim.drones.iter().filter(|d| !any || !d.alive() || sim.tracked(d.id)) {
-        match scope(d.pos) {
+    let picture = sim.picture();
+    let now = sim.tick;
+    for d in sim.drones.iter().filter(|d| !any || !d.alive() || picture.contains_key(&d.id)) {
+        let track = picture.get(&d.id).filter(|_| any && d.alive());
+        let (pos, vel) = track.map_or((d.pos, d.vel), |t| (t.est(now), t.vel));
+        match scope(pos) {
             Some((x, y, bearing)) => {
-                let a = fade(bearing);
                 if d.alive() {
-                    s.push(square(x, y, 1.8, alpha(0xFF4040, a)));
+                    // Fresh: bright and red; a forecast: orange, fading as it ages towards the track's drop.
+                    let (a, color) = match track {
+                        Some(t) if t.forecast(now) => ((1.0 - t.age(now) as f64 / t.ttl.max(1) as f64 * 0.7).max(0.3), 0xFFB040),
+                        Some(_) => (1.0, 0xFF4040),
+                        None => (fade(bearing), 0xFF4040),
+                    };
+                    s.push(square(x, y, 1.8, alpha(color, a)));
                     // Its heading, a short tail.
-                    let v = d.vel.normalize_or_zero();
-                    s.push(quad(pt(x, y), pt(x + 0.6, y), pt(x - v.x as f32 * 6.0 + 0.6, y - v.z as f32 * 6.0), pt(x - v.x as f32 * 6.0, y - v.z as f32 * 6.0), alpha(0xFF4040, a * 0.6)));
+                    let v = vel.normalize_or_zero();
+                    s.push(quad(pt(x, y), pt(x + 0.6, y), pt(x - v.x as f32 * 6.0 + 0.6, y - v.z as f32 * 6.0), pt(x - v.x as f32 * 6.0, y - v.z as f32 * 6.0), alpha(color, a * 0.6)));
                 } else {
-                    s.push(square(x, y, 1.2, alpha(0x909090, a)));
+                    s.push(square(x, y, 1.2, alpha(0x909090, fade(bearing))));
                 }
             }
             None if d.alive() => far += 1,
             None => {}
         }
+        // The true place, when asked for: a white dot beside the track, to see how far the picture is off.
+        if sim.truth && d.alive() && any {
+            if let Some((x, y, _)) = scope(d.pos) {
+                s.push(square(x, y, 0.8, 0xFFFFFFFF));
+            }
+        }
     }
     // The player: a white arrow the way they look.
     // Minecraft's yaw 0 looks south (+z, down the scope).

airdef-mod/src/replay.rs

@@ -107,6 +107,7 @@ pub fn title(rec: &Recording, i: usize) -> String {
         EventKind::Hit { kind, .. } => format!("Прилёт: «{}»", kind.spec().name),
         EventKind::SamLost { kind, index, .. } => format!("{} №{} уничтожен", kind.name(), index + 1),
         EventKind::Split { .. } => "«Орешник»: разделение боевых блоков".into(),
+        EventKind::Crash { kind, .. } => format!("«{}» разбивается о препятствие", kind.spec().name),
     }
 }
 
@@ -122,6 +123,7 @@ pub fn row(rec: &Recording, i: usize) -> String {
         EventKind::Hit { kind, .. } => format!("{}: прилёт", kind.spec().name),
         EventKind::SamLost { kind, index, .. } => format!("{}-{} уничтожен", kind.name(), index + 1),
         EventKind::Split { .. } => "Орешник: разделение".into(),
+        EventKind::Crash { kind, .. } => format!("{}: о рельеф", kind.spec().name),
     };
     format!("{} {what}", clock(e.at as f64))
 }
@@ -152,6 +154,7 @@ fn interest(rec: &Recording, i: usize) -> f64 {
             power as f64 * 1.5 + if object.is_some() { 6.0 } else if sam.is_some() { 5.0 } else { 0.0 }
         }
         EventKind::SamLost { .. } => 12.0,
+        EventKind::Crash { power, .. } => power as f64,
         EventKind::Split { drone } => {
             // The bus's split, not each block's.
             let first = rec.events.iter().position(|o| matches!(o.kind, EventKind::Split { .. }));
@@ -168,6 +171,7 @@ fn clip(rec: &Recording, i: usize) -> Clip {
         EventKind::Hit { .. } => (160.0, 60.0),
         EventKind::SamLost { .. } => (80.0, 90.0),
         EventKind::Split { .. } => (40.0, 170.0),
+        EventKind::Crash { .. } => (120.0, 60.0),
     };
     Clip { event: i, from: (at - before).max(0.0), to: (at + after).min(rec.len as f64) }
 }
@@ -293,6 +297,11 @@ impl Player {
         self.fade = 6;
     }
 
+    /// The time of day the raid was flown in, as of the replay's moment now.
+    pub fn day_time(&self, sim: &Sim) -> Option<u64> {
+        sim.replay(self.rec)?.day_time(self.t)
+    }
+
     /// One tick: time runs, the ghosts fly, the director films. Models and sounds go to `out`.
     pub fn tick(&mut self, sim: &Sim, listener: DVec3, out: &mut Out) {
         let Some(rec) = sim.replay(self.rec) else {
@@ -352,7 +361,7 @@ impl Player {
         for e in rec.events.iter().filter(|e| (self.heard..self.t).contains(&(e.at as f64))) {
             let event = match e.kind {
                 EventKind::Kill { .. } => "airdef:blast.air",
-                EventKind::Hit { power, .. } => ["airdef:blast.air", "airdef:blast.medium", "airdef:blast.big", "airdef:blast.heavy", "airdef:blast.huge"][(power as usize).min(4)],
+                EventKind::Hit { power, .. } | EventKind::Crash { power, .. } => ["airdef:blast.air", "airdef:blast.medium", "airdef:blast.big", "airdef:blast.heavy", "airdef:blast.huge"][(power as usize).min(4)],
                 EventKind::SamLost { .. } => "airdef:blast.big",
                 EventKind::Split { .. } => "airdef:boom.sonic",
             };
@@ -412,7 +421,7 @@ impl Player {
                     }
                 }
             }
-            EventKind::Hit { drone, .. } => {
+            EventKind::Hit { drone, .. } | EventKind::Crash { drone, .. } => {
                 if t < te - 50.0 {
                     if let Some((eye, look)) = chase(drone, 12.0, 4.0) {
                         return (eye, look, 55.0, 0);
@@ -672,7 +681,7 @@ impl Player {
                     s.push(line((x - 2.5, y - 2.5), (x + 2.5, y + 2.5), 1.2, 0xFFFFE040));
                     s.push(line((x + 2.5, y - 2.5), (x - 2.5, y + 2.5), 1.2, 0xFFFFE040));
                 }
-                EventKind::Hit { power, .. } => {
+                EventKind::Hit { power, .. } | EventKind::Crash { power, .. } => {
                     let r = 2.0 + power as f32;
                     s.push(fill(x - r, y - r, r * 2.0, r * 2.0, 0xB0FF3020));
                 }
@@ -705,6 +714,7 @@ impl Player {
             let c = match e.kind {
                 EventKind::Kill { .. } => 0xFFFFE040,
                 EventKind::Hit { .. } => 0xFFFF3020,
+                EventKind::Crash { .. } => 0xFF903020,
                 EventKind::SamLost { .. } => 0xFFFF00FF,
                 EventKind::Split { .. } => 0xFFFF9020,
             };

airdef-mod/src/sim/damage.rs

@@ -8,6 +8,124 @@ use super::*;
 /// By blast power (as `explode` grades it): how far it reaches a vehicle, and how hard it hits one at the centre.
 const REACH: [f64; 5] = [4.0, 7.0, 12.0, 18.0, 26.0];
 const HIT: [f64; 5] = [0.2, 0.45, 0.85, 1.25, 1.7];
+/// A unit's working parts, each 1 (whole) to 0 (failed); the hull is `Sam::health` (0 destroys it).
+#[derive(Clone, Copy, PartialEq, Eq, Debug)]
+pub enum Part {
+    /// The radar (or optics): its reach and its scan.
+    Sensor,
+    /// The aiming drive of the launcher or turret.
+    Mount,
+    /// The launcher: cells, reload.
+    Launcher,
+    /// The gun: it jams.
+    Gun,
+    /// The running gear: it can't march when it fails.
+    Tracks,
+    /// The data link: no network when it fails.
+    Comms,
+}
+
+#[derive(Clone, Copy, PartialEq, Eq, Debug)]
+pub enum PartState {
+    Ok,
+    Damaged,
+    Failed,
+}
+
+impl Part {
+    pub const ALL: [Part; 6] = [Part::Sensor, Part::Mount, Part::Launcher, Part::Gun, Part::Tracks, Part::Comms];
+    pub fn name(self) -> &'static str {
+        match self {
+            Part::Sensor => "РЛС",
+            Part::Mount => "привод наведения",
+            Part::Launcher => "пусковая",
+            Part::Gun => "орудие",
+            Part::Tracks => "ходовая",
+            Part::Comms => "связь",
+        }
+    }
+    pub fn short(self) -> &'static str {
+        match self {
+            Part::Sensor => "РЛС",
+            Part::Mount => "Прив",
+            Part::Launcher => "ПУ",
+            Part::Gun => "Ор",
+            Part::Tracks => "Ход",
+            Part::Comms => "Св",
+        }
+    }
+    fn index(self) -> usize {
+        self as usize
+    }
+    /// Whether this kind of unit has the part at all.
+    pub fn on(self, kind: SamKind) -> bool {
+        let spec = kind.spec();
+        match self {
+            Part::Sensor => spec.sensor > 0.0,
+            Part::Mount => kind.armed() && kind != SamKind::Light && (spec.missile.is_some() || spec.gun.is_some()),
+            Part::Launcher => spec.missile.is_some(),
+            Part::Gun => spec.gun.is_some(),
+            Part::Tracks => kind.mobile(),
+            Part::Comms => true,
+        }
+    }
+    /// Where the part is on the vehicle: right, up, back, blocks at scale 1 (the nose points to -back).
+    fn place(self, spec: &super::units::SamSpec) -> (f64, f64, f64) {
+        match self {
+            Part::Sensor => (0.0, spec.mast / spec.scale, 1.0),
+            Part::Mount => (0.0, spec.mount.0, -spec.mount.1),
+            Part::Launcher => (0.0, spec.mount.0, -spec.mount.1 + 0.4),
+            Part::Gun => (0.0, spec.mount.0, -spec.mount.1 - 1.0),
+            Part::Tracks => (0.0, 0.3, 0.0),
+            Part::Comms => (0.0, 1.6, 1.8),
+        }
+    }
+}
+
+/// Below this a part is damaged (works worse), at 0 it has failed.
+pub const WORN: f64 = 0.6;
+
+/// The state of every part: `Part::ALL`'s order.
+#[derive(Clone, Copy, PartialEq, Debug)]
+pub struct Comps(pub [f64; 6]);
+
+impl Default for Comps {
+    fn default() -> Self {
+        Self([1.0; 6])
+    }
+}
+
+impl Comps {
+    pub fn get(&self, p: Part) -> f64 {
+        self.0[p.index()]
+    }
+    pub fn state(&self, p: Part) -> PartState {
+        let v = self.get(p);
+        if v <= 0.0 {
+            PartState::Failed
+        } else if v < WORN {
+            PartState::Damaged
+        } else {
+            PartState::Ok
+        }
+    }
+    pub fn whole(&self) -> bool {
+        self.0.iter().all(|&v| v >= 1.0)
+    }
+    /// Parts of this kind that are not whole, as "РЛС 40%, ходовая отказ".
+    pub fn describe(&self, kind: SamKind) -> String {
+        Part::ALL
+            .iter()
+            .filter(|p| p.on(kind) && self.get(**p) < 1.0)
+            .map(|p| match self.state(*p) {
+                PartState::Failed => format!("{} отказ", p.short()),
+                _ => format!("{} {:.0}%", p.short(), self.get(*p) * 100.0),
+            })
+            .collect::<Vec<_>>()
+            .join(", ")
+    }
+}
+
 /// Health points an object loses at the centre of a blast.
 const OBJECT_HIT: [f64; 5] = [2.0, 6.0, 14.0, 26.0, 40.0];
 
@@ -28,7 +146,72 @@ impl MissileKind {
     }
 }
 
+/// A strike that ends farther than this from its aim point misses (the lethal radius of a point target).
+pub(super) const MISS_RADIUS: f64 = 3.0;
+/// A system's hull, as a cylinder: its radius (× scale) and how far above the ground it reaches (× scale).
+const HULL_RADIUS: f64 = 2.2;
+const HULL_TOP: f64 = 3.0;
+
+impl DroneKind {
+    /// Strike accuracy: the CEP (blocks; half the strikes land within it, the scatter is Rayleigh)
+    /// and the share of strikes with a rare gross navigation fault, which lands beyond `MISS_RADIUS`.
+    pub(super) fn accuracy(self) -> (f64, f64) {
+        match self {
+            DroneKind::Shahed => (1.2, 0.03),
+            DroneKind::Geran3 => (1.0, 0.03),
+            DroneKind::Lancet => (0.8, 0.02),
+            DroneKind::Gerbera => (1.5, 0.04),
+            DroneKind::Kh101 => (1.3, 0.05),
+            DroneKind::Kalibr => (1.3, 0.05),
+            DroneKind::Kh22 => (1.6, 0.06),
+            DroneKind::Zircon => (1.5, 0.06),
+            DroneKind::Iskander => (1.4, 0.06),
+            DroneKind::Kinzhal => (1.5, 0.06),
+            // The bus and its blocks: the blocks are aimed by the split, so only the bus's own error applies.
+            DroneKind::Oreshnik | DroneKind::OreshnikBlock | DroneKind::OreshnikSub => (1.6, 0.08),
+        }
+    }
+}
+
 impl Sim {
+    /// The aim error of a new strike: drawn once from the seed, the drone keeps it for its whole flight.
+    pub(super) fn aim_error(&mut self, kind: DroneKind) -> DVec3 {
+        let (cep, gross) = kind.accuracy();
+        let angle = self.rng.f() * std::f64::consts::TAU;
+        let r = if self.rng.chance(gross) {
+            MISS_RADIUS + cep * (0.5 + 2.5 * self.rng.f())
+        } else {
+            // Rayleigh with its median at the CEP.
+            let u = 1.0 - self.rng.f();
+            cep * (-2.0 * u.ln() / (2.0 * std::f64::consts::LN_2)).sqrt()
+        };
+        DVec3::new(angle.cos() * r, 0.0, angle.sin() * r)
+    }
+
+    /// An armed warhead reached `pos` (its last step was `vel`): a system whose hull it swept through is
+    /// destroyed at once, whatever the blast would have done to it. A near miss is only splash.
+    pub(super) fn direct_hit(&mut self, pos: DVec3, vel: DVec3, tnt: u32, out: &mut Out) {
+        if !self.damage || tnt == 0 {
+            return;
+        }
+        let from = pos - vel;
+        for i in 0..self.sams.len() {
+            let sam = &self.sams[i];
+            if !sam.alive() {
+                continue;
+            }
+            let s = sam.kind.spec().scale;
+            let hit = (0..=8).any(|k| {
+                let p = from.lerp(pos, k as f64 / 8.0);
+                let across = DVec3::new(p.x - sam.pos.x, 0.0, p.z - sam.pos.z).length();
+                across <= HULL_RADIUS * s && p.y >= sam.pos.y - 1.0 && p.y <= sam.pos.y + HULL_TOP * s
+            });
+            if hit {
+                self.destroy(i, out);
+            }
+        }
+    }
+
     /// A blast of `power` (0 to 4) at `pos`: the systems and objects round it take damage.
     pub(super) fn blast_damage(&mut self, pos: DVec3, power: usize, out: &mut Out) {
         let (reach, hit) = (REACH[power], HIT[power]);
@@ -47,9 +230,39 @@ impl Sim {
             sam.health -= hit * k * k * if d < 1.0 { 1.5 } else { 1.0 };
             if sam.health <= 0.0 {
                 destroyed.push(i);
-            } else if before >= 0.5 && sam.health < 0.5 {
+                continue;
+            }
+            if before >= 0.5 && sam.health < 0.5 {
                 out.messages.push(format!("{} №{} повреждён", sam.kind.name(), i + 1));
             }
+            // The parts take the blast by their own distance from it: the side it came from decides which.
+            let spec = sam.kind.spec();
+            let rot = DQuat::from_rotation_y(sam.heading);
+            for part in Part::ALL {
+                if !part.on(sam.kind) {
+                    continue;
+                }
+                let (x, y, back) = part.place(spec);
+                let at = sam.pos + rot * DVec3::new(x, y, back) * spec.scale;
+                let size = if part == Part::Tracks { 2.5 } else { 1.0 };
+                let dp = (at.distance(pos) - size).max(0.0);
+                if dp >= reach {
+                    continue;
+                }
+                let kp = 1.0 - dp / reach;
+                let roll = dice(self.seed, self.tick, sam.id as u64, part as u64);
+                // The parts are softer than the hull: a blast the hull survives can still put one out.
+                let dmg = hit * kp * kp * (0.7 + roll) * 1.5 * if dp < 1.0 { 1.4 } else { 1.0 };
+                let was = sam.comps.state(part);
+                let v = &mut sam.comps.0[part as usize];
+                *v = (*v - dmg).max(0.0);
+                let now = sam.comps.state(part);
+                if now != was && now != PartState::Ok {
+                    let word = if now == PartState::Failed { "отказал(а)" } else { "повреждён(а)" };
+                    out.messages.push(format!("{} №{}: {} {word}", sam.kind.name(), i + 1, part.name()));
+                }
+            }
+            sam.fit_cells();
         }
         for i in destroyed {
             self.destroy(i, out);
@@ -79,6 +292,9 @@ impl Sim {
         sam.target = None;
         sam.gun_target = None;
         sam.reloading = 0;
+        sam.tracks.clear();
+        sam.seen.clear();
+        sam.own.clear();
         let spec = sam.kind.spec();
         let missiles = sam.missiles;
         let bursts = sam.bursts;
@@ -159,11 +375,76 @@ impl Sim {
 
 }
 
+/// A roll from 0 to 1 fixed by the seed and three numbers: the same events roll the same in every run,
+/// and the simulation's own random sequence is left alone.
+pub(super) fn dice(seed: u64, a: u64, b: u64, c: u64) -> f64 {
+    let mut x = seed ^ a.wrapping_mul(0x9E37_79B9_7F4A_7C15) ^ b.wrapping_mul(0xBF58_476D_1CE4_E5B9) ^ c.wrapping_mul(0x94D0_49BB_1331_11EB);
+    x = (x ^ (x >> 30)).wrapping_mul(0xBF58_476D_1CE4_E5B9);
+    x = (x ^ (x >> 27)).wrapping_mul(0x94D0_49BB_1331_11EB);
+    x ^= x >> 31;
+    (x >> 11) as f64 / (1u64 << 53) as f64
+}
+
 impl Sam {
     /// Its wreck still burns.
     pub fn burning(&self) -> bool {
         self.burn > 0
     }
+    /// A part's state, `Ok` for one this unit does not have.
+    pub fn part(&self, p: Part) -> f64 {
+        if p.on(self.kind) { self.comps.get(p) } else { 1.0 }
+    }
+    pub fn part_state(&self, p: Part) -> PartState {
+        if p.on(self.kind) { self.comps.state(p) } else { PartState::Ok }
+    }
+    pub fn parts_text(&self) -> String {
+        self.comps.describe(self.kind)
+    }
+    /// The aiming drive's share of its speed: a failed one doesn't turn at all.
+    pub(super) fn drive_fit(&self) -> f64 {
+        let h = self.part(Part::Mount);
+        if h <= 0.0 { 0.0 } else { 0.3 + 0.7 * h }
+    }
+    /// The radar's share of its reach; the scan is slower by the same.
+    pub(super) fn radar_fit(&self) -> f64 {
+        let h = self.part(Part::Sensor);
+        if h <= 0.0 { 0.0 } else { 0.4 + 0.6 * h }
+    }
+    /// The gun's share of its hit chance.
+    pub(super) fn gun_fit(&self) -> f64 {
+        0.5 + 0.5 * self.part(Part::Gun)
+    }
+    /// Its launcher's cells still good: a damaged one holds fewer missiles.
+    pub(super) fn cells(&self) -> u32 {
+        let Some(load) = &self.kind.spec().missile else { return 0 };
+        let h = self.part(Part::Launcher);
+        if h <= 0.0 { 0 } else { ((load.magazine as f64 * (0.4 + 0.6 * h)).ceil() as u32).clamp(1, load.magazine) }
+    }
+    /// Missiles above what the cells hold are lost with them.
+    pub fn fit_cells(&mut self) {
+        if self.kind.spec().missile.is_some() {
+            self.missiles = self.missiles.min(self.cells());
+        }
+    }
+    /// Ticks a reload takes: longer with a damaged launcher.
+    pub(super) fn reload_time(&self) -> u32 {
+        let r = self.kind.spec().reload.max(1);
+        (r as f64 * (1.0 + 1.5 * (1.0 - self.part(Part::Launcher)))).round() as u32
+    }
+    /// The gun fires (not jammed for good, not jammed now).
+    pub(super) fn gun_up(&self) -> bool {
+        self.part(Part::Gun) > 0.0 && self.jam == 0
+    }
+    /// How far it can march: the running gear's share of the speed (0 can't).
+    pub(super) fn drive_speed(&self) -> f64 {
+        let h = self.part(Part::Tracks);
+        if h <= 0.0 { 0.0 } else { 0.35 + 0.65 * h }
+    }
+    /// The data link's reach, 0 when the link has failed.
+    pub(super) fn link_range(&self) -> f64 {
+        let h = self.part(Part::Comms);
+        if h <= 0.0 { 0.0 } else { super::sight::LINK * (0.3 + 0.7 * h) }
+    }
 }
 
 impl Sim {
@@ -171,9 +452,11 @@ impl Sim {
     pub fn repair(&mut self) -> u32 {
         let mut n = 0;
         for sam in &mut self.sams {
-            if sam.health < 1.0 {
+            if sam.health < 1.0 || !sam.comps.whole() {
                 n += 1;
             }
+            sam.comps = Comps::default();
+            sam.jam = 0;
             let spec = sam.kind.spec();
             sam.health = 1.0;
             sam.burn = 0;
@@ -191,6 +474,7 @@ impl Sim {
         }
         // The wrecks' ammunition still to cook off goes with them.
         self.later.clear();
+        self.fires.extinguish();
         n
     }
 

airdef-mod/src/sim/fires.rs

@@ -0,0 +1,223 @@
+//! Long fires (#52): where a drone or a missile came down, where a warhead struck and on a
+//! destroyed system a fire burns for minutes: it flares up, burns steadily, smokes thick and
+//! heavy, dies down and smoulders. Visual first (flames, smoke columns, a flickering light, a
+//! crackle); with damage on, a few real fire blocks on solid ground (never on water or in the
+//! air), put back while it burns and taken away when it is out. At most `MAX` fires burn, the
+//! oldest dying down first. A replay draws the same fires from its events (`replay_fire`).
+use super::*;
+
+/// Fires burning at once.
+pub const MAX: usize = 12;
+/// A fire put out by the water it fell in lasts this long (steam only).
+const STEAM: u32 = 160;
+/// Ticks the oldest fire has left when a newer one pushes it out.
+const FADE: u32 = 160;
+/// Ticks between the fire blocks being set again.
+const REFRESH: u64 = 80;
+
+pub struct Fire {
+    pub id: u32,
+    pub at: DVec3,
+    pub start: u64,
+    pub life: u32,
+    /// 0.6 (a crashed drone) to 3 (a cruise or ballistic warhead, a depot).
+    pub size: f32,
+    /// The system it burns on, if any: its own wreck fire does the flames for as long as it lasts.
+    host: Option<u32>,
+    /// The land under it found: `Some(true)` land, `Some(false)` water (steam only).
+    land: Option<bool>,
+    /// Asked about the ground since this tick.
+    asked: u64,
+    /// Fire blocks set (whole coordinates).
+    blocks: Vec<(i32, i32, i32)>,
+    /// The host's wreck is flaming: this fire leaves the flames to it.
+    pub quiet: bool,
+}
+
+#[derive(Default)]
+pub struct Fires {
+    pub list: Vec<Fire>,
+    /// Commands to take fire blocks away, sent next tick.
+    cleanup: Vec<String>,
+}
+
+/// How long a fire of this power burns, in ticks: 2 to 5 minutes.
+pub fn life_for(power: u32) -> u32 {
+    2400 + 900 * power.min(4)
+}
+
+/// The size of a fire of this power.
+pub fn size_for(power: u32) -> f32 {
+    [0.6, 1.0, 1.6, 2.4, 3.0][power.min(4) as usize]
+}
+
+/// How strong the flames (`.0`) and the smoke (`.1`) are, 0 to about 1, `age` ticks into a fire
+/// that burns `life`: flaring up, steady flame, thick smoke while it dies down, then embers.
+pub fn level(age: f64, life: f64) -> (f32, f32) {
+    let f = (age / life.max(1.0)).clamp(0.0, 1.0);
+    let flare = if age < 40.0 { 0.35 + 0.65 * age / 40.0 } else { 1.0 };
+    let flame = if f < 0.45 { flare } else { flare * (1.0 - (f - 0.45) / 0.4).clamp(0.0, 1.0) };
+    let smoke = if age < 100.0 { age / 100.0 } else if f < 0.8 { 1.0 } else { 1.0 - 0.85 * (f - 0.8) / 0.2 };
+    (flame as f32, smoke.clamp(0.0, 1.0) as f32)
+}
+
+impl Fires {
+    /// Fires burning now.
+    pub fn len(&self) -> usize {
+        self.list.len()
+    }
+    pub fn is_empty(&self) -> bool {
+        self.list.is_empty()
+    }
+    /// Puts every fire out; the fire blocks are taken away on the next step.
+    pub fn extinguish(&mut self) {
+        let list = std::mem::take(&mut self.list);
+        for f in list {
+            self.cleanup.extend(f.take_blocks());
+        }
+    }
+}
+
+impl Fire {
+    fn take_blocks(self) -> Vec<String> {
+        self.blocks
+            .into_iter()
+            .map(|(x, y, z)| format!("fill {x} {y} {z} {x} {y} {z} minecraft:air replace minecraft:fire"))
+            .collect()
+    }
+    /// How strong it burns at tick `now`: (flames, smoke); water leaves steam only.
+    pub fn level(&self, now: u64) -> (f32, f32) {
+        let (fl, sm) = level(now.saturating_sub(self.start) as f64, self.life as f64);
+        if self.land == Some(false) { (0.0, sm * 0.5) } else { (fl, sm) }
+    }
+}
+
+impl Sim {
+    /// Something came down or struck at `pos` (power 0 to 4): a fire starts there, or the fire
+    /// already burning close by grows. `host` is the system it burns on.
+    pub(super) fn ignite(&mut self, pos: DVec3, power: u32, host: Option<u32>) {
+        let now = self.tick;
+        let (size, life) = (size_for(power), life_for(power));
+        if let Some(f) = self.fires.list.iter_mut().find(|f| f.at.distance(pos) < 6.0) {
+            // The same spot (a warhead and the wreck it made): one fire, the greater of the two.
+            f.size = f.size.max(size);
+            f.life = f.life.max((now - f.start) as u32 + life);
+            f.host = f.host.or(host);
+            return;
+        }
+        let id = self.id();
+        self.fires.list.push(Fire {
+            id,
+            at: pos,
+            start: now,
+            life,
+            size,
+            host,
+            land: None,
+            asked: 0,
+            blocks: Vec::new(),
+            quiet: false,
+        });
+        if self.fires.list.len() > MAX {
+            // The oldest dies down (and is gone) instead of burning on.
+            let old = self.fires.list.iter_mut().filter(|f| now.saturating_sub(f.start) as u32 + FADE < f.life).min_by_key(|f| f.start);
+            if let Some(f) = old {
+                f.life = (now - f.start) as u32 + FADE;
+            }
+        }
+    }
+
+    /// Once a tick: finds the ground under each new fire, burns the old ones, ends the burnt out.
+    pub(super) fn step_fires(&mut self, ground: &mut Ground, out: &mut Out) {
+        let now = self.tick;
+        out.commands.append(&mut self.fires.cleanup);
+        let damage = self.damage;
+        let mut fires = std::mem::take(&mut self.fires.list);
+        for f in &mut fires {
+            let age = now.saturating_sub(f.start);
+            // Where the land is under it: it burns on the surface, not at the height of what fell.
+            if f.land.is_none() && age >= f.asked {
+                f.asked = age + 10;
+                if let Some(h) = ground.at(f.at, now) {
+                    let (x, z) = (f.at.x.floor() as i32, f.at.z.floor() as i32);
+                    let h = h as i32;
+                    if ground.world.is_known_solid(x, h - 1, z, now) {
+                        f.at.y = h as f64;
+                        f.land = Some(true);
+                    } else if ground.world.is_known_open(x, h - 1, z, now) {
+                        // Water (or another fluid): the fire goes out in a cloud of steam.
+                        f.at.y = h as f64;
+                        f.land = Some(false);
+                        f.life = f.life.min(age as u32 + STEAM);
+                    }
+                }
+                // Not known for a while: it burns where it is, on the land.
+                if f.land.is_none() && age > 100 {
+                    f.land = Some(true);
+                }
+            }
+            f.quiet = f.host.is_some_and(|id| self.sams.iter().any(|s| s.id == id && !s.alive() && s.burn > 0));
+            let (fl, sm) = f.level(now);
+            let s = f.size;
+            if !f.quiet {
+                let top = f.at + DVec3::Y * 0.4;
+                let spread = 0.4 + 0.5 * s;
+                if fl > 0.04 && now % 2 == 0 {
+                    out.particles("minecraft:flame", top, spread, DVec3::new(0.0, 0.05 + 0.05 * fl as f64, 0.0), 0.02, (3.0 * s * fl).ceil() as u32);
+                }
+                if sm > 0.04 && now % 3 == 0 {
+                    out.particles("minecraft:large_smoke", top + DVec3::Y * 0.6, spread, DVec3::new(0.0, 0.1, 0.0), 0.03, (2.0 * s * sm).ceil() as u32);
+                }
+                // The tall column: a plume that rises far.
+                if sm > 0.3 && now % 6 == (f.id % 6) as u64 {
+                    out.particles("minecraft:campfire_signal_smoke", top, 0.5 * s, DVec3::new(0.0, 0.09, 0.0), 0.01, 1 + (s * sm) as u32);
+                }
+                if fl > 0.5 && now % 20 == (f.id % 20) as u64 {
+                    out.particles("minecraft:lava", top + DVec3::Y * 0.5, 0.4 * s, DVec3::new(0.0, 0.2, 0.0), 0.1, 2);
+                }
+                if now % 50 == (f.id % 50) as u64 && fl + sm * 0.3 > 0.1 {
+                    out.sound("minecraft:block.fire.ambient", f.at, 0.5 + 1.2 * fl, 0.8 + 0.2 * s.min(1.0));
+                }
+            }
+            // Real fire, only where the damage is real: a few blocks on the solid ground.
+            if damage && f.land == Some(true) && fl > 0.3 && now % REFRESH == (f.id as u64) % REFRESH && age >= 20 {
+                let (x, y, z) = (f.at.x.floor() as i32, f.at.y.floor() as i32, f.at.z.floor() as i32);
+                let n = if s >= 2.5 { 5 } else if s >= 1.5 { 3 } else { 1 };
+                for k in 0..n {
+                    let (dx, dz) = if k == 0 { (0, 0) } else { [(1, 0), (-1, 0), (0, 1), (0, -1)][k - 1] };
+                    let (bx, bz) = (x + dx, z + dz);
+                    // Only where the land is as high as at the centre.
+                    let level = ground.at(DVec3::new(bx as f64 + 0.5, 0.0, bz as f64 + 0.5), now).is_some_and(|h| h as i32 == y);
+                    if level && ground.world.is_known_solid(bx, y - 1, bz, now) && ground.world.is_known_open(bx, y, bz, now) {
+                        out.commands.push(format!("setblock {bx} {y} {bz} minecraft:fire keep"));
+                        if !f.blocks.contains(&(bx, y, bz)) {
+                            f.blocks.push((bx, y, bz));
+                        }
+                    }
+                }
+            }
+        }
+        // The burnt out: their fire blocks go too.
+        let mut keep = Vec::with_capacity(fires.len());
+        for f in fires {
+            if now.saturating_sub(f.start) < f.life as u64 {
+                keep.push(f);
+            } else {
+                out.commands.extend(f.take_blocks());
+            }
+        }
+        // Fires lit this very tick were pushed to the list meanwhile (none are: ignite runs inside the step).
+        keep.append(&mut self.fires.list);
+        self.fires.list = keep;
+    }
+}
+
+/// A fire for a replay: the event's power at age `age` ticks, as a glowing flame model's scale
+/// (zero when it is out or not started) and a smoke strength.
+pub fn replay_fire(power: u32, age: f64) -> (f32, f32) {
+    if age < 0.0 {
+        return (0.0, 0.0);
+    }
+    let (fl, sm) = level(age, life_for(power) as f64);
+    (fl * size_for(power), sm)
+}

airdef-mod/src/sim/logistics.rs

@@ -50,7 +50,7 @@ impl Sim {
         // The trucks: a job each, when idle.
         for t in 0..self.sams.len() {
             let truck = &self.sams[t];
-            if truck.kind != SamKind::Tzm || !truck.alive() || truck.moving() || now % 10 != t as u64 % 10 {
+            if truck.kind != SamKind::Tzm || !truck.alive() || truck.moving() || truck.drive_speed() <= 0.0 || now % 10 != t as u64 % 10 {
                 continue;
             }
             let at = truck.pos;
@@ -116,7 +116,7 @@ impl Sim {
     fn reload_now(&mut self, i: usize, out: &mut Out) {
         let sam = &mut self.sams[i];
         sam.empty = false;
-        sam.reloading = sam.kind.spec().reload.max(1);
+        sam.reloading = sam.reload_time();
         out.sound("minecraft:block.piston.extend", sam.pos, 2.0, 0.6);
     }
 }

airdef-mod/src/sim/mod.rs

@@ -10,6 +10,7 @@ use glam::{DQuat, DVec3};
 use std::collections::HashMap;
 
 mod damage;
+pub mod fires;
 mod raid;
 pub mod record;
 mod sight;
@@ -19,9 +20,15 @@ mod logistics;
 mod orders;
 mod units;
 mod why;
+pub mod world;
 #[cfg(test)]
 mod regress;
+#[cfg(test)]
+mod sensor_tests;
 pub use ew::EW_RADIUS;
+pub use damage::{Comps, Part, PartState};
+pub use sight::{Ident, Track};
+use damage::dice;
 pub use units::{Family, SamKind};
 use units::Muzzle;
 pub use raid::{Approach, Aim, RaidOrder};
@@ -211,6 +218,8 @@ pub struct Ground {
     asked: std::collections::HashSet<(i32, i32)>,
     /// The tick of the last full clean-up (a big cache would otherwise be scanned on every answer).
     swept: u64,
+    /// The blocks themselves (issues #42, #43): what stops a flight.
+    pub world: world::WorldCache,
 }
 
 /// Ticks between full clean-ups of a big ground cache.
@@ -251,10 +260,32 @@ impl Ground {
         self.asked.clear();
         std::mem::take(&mut self.wanted)
     }
+    /// The first solid block on the way from `a` to `b` (the real blocks, not the height of the land).
+    pub fn sweep(&mut self, a: DVec3, b: DVec3, skip_start: bool, now: u64) -> world::Sweep {
+        self.world.sweep(a, b, skip_start, now)
+    }
+    /// Has the sections along a flight read before it gets there.
+    pub fn ahead(&mut self, pos: DVec3, vel: DVec3, ticks: f64, now: u64) {
+        self.world.look_ahead(pos, vel, ticks, now);
+    }
+    /// Whether `pos` is in the land by the column's height (`below`, as `at` gave it), given what the sweep
+    /// of this step saw: over blocks known and open, the height only counts where its top block is known
+    /// to be open, a fluid's surface (not a roof or a bridge deck above the flight, nor a block unread).
+    pub fn ground_hit(&mut self, below: Option<f64>, pos: DVec3, offset: f64, sweep: &world::Sweep, now: u64) -> bool {
+        let Some(g) = below else { return false };
+        if pos.y > g + offset {
+            return false;
+        }
+        match sweep {
+            world::Sweep::Clear => self.world.is_known_open(pos.x.floor() as i32, g.floor() as i32 - 1, pos.z.floor() as i32, now),
+            _ => true,
+        }
+    }
     /// Explosions change the land: forget what was known round them.
     fn forget(&mut self, at: DVec3, radius: i32) {
         let (cx, cz) = (at.x.floor() as i32, at.z.floor() as i32);
         self.known.retain(|&(x, z), _| (x - cx).abs() > radius || (z - cz).abs() > radius);
+        self.world.touched(at, f64::from(radius) + 2.0);
     }
 }
 
@@ -722,9 +753,13 @@ impl Drone {
     }
     /// How much a system wants to shoot it: fast and heavy first, decoys look real.
     fn threat(&self, from: DVec3) -> f64 {
+        self.threat_at(from, self.pos)
+    }
+    /// The same for a target believed to be at `at` (a track's forecast).
+    fn threat_at(&self, from: DVec3, at: DVec3) -> f64 {
         let s = self.kind.spec();
         let warhead = if s.decoy { 3.0 } else { s.warhead as f64 };
-        (1.0 + warhead) * (1.0 + s.speed) / (1.0 + self.pos.distance(from) * 0.02)
+        (1.0 + warhead) * (1.0 + s.speed) / (1.0 + at.distance(from) * 0.02)
     }
 }
 
@@ -1009,7 +1044,14 @@ pub struct Sam {
     pub health: f64,
     /// Ticks its wreck still burns.
     burn: u32,
-    /// The drones it has tracks of this tick: its own radar's and the network's.
+    /// Its working parts (the hull is `health`).
+    pub comps: Comps,
+    /// Ticks its gun stays jammed.
+    jam: u32,
+    /// Where its radar beam points (radians), and the tracks it holds: its own radar's and the network's.
+    pub(super) beam: f64,
+    pub tracks: Vec<Track>,
+    /// The ids of the tracks it holds this tick: its own radar's and the network's.
     pub seen: Vec<u32>,
     /// The drones its own radar (or optics) holds: guns need these.
     pub own: Vec<u32>,
@@ -1062,6 +1104,10 @@ impl Sam {
             launched: 0,
             health: 1.0,
             burn: 0,
+            comps: Comps::default(),
+            jam: 0,
+            beam: id as f64 * 2.4,
+            tracks: Vec::new(),
             seen: Vec::new(),
             own: Vec::new(),
             kill_view: None,
@@ -1083,12 +1129,16 @@ impl Sam {
     pub fn alive(&self) -> bool {
         self.health > 0.0
     }
+    /// Where its radar beam points now (radians clockwise from north).
+    pub fn beam(&self) -> f64 {
+        self.beam
+    }
     /// How well it still works: turning, aiming, its radar's reach.
     /// Turns the mount towards `yaw` (and `pitch`, if it elevates) under its drive's limits; a damaged
     /// system has the less of both speed and acceleration.
     fn aim_towards(&mut self, yaw: f64, pitch: Option<f64>) {
         let d = self.kind.spec().drive();
-        let fit = self.fitness();
+        let fit = self.drive_fit();
         self.yaw += drive(&mut self.yaw_vel, angle_diff(self.yaw, yaw), d.yaw.0 * fit, d.yaw.1 * fit);
         if let Some(pitch) = pitch {
             self.pitch += drive(&mut self.pitch_vel, pitch - self.pitch, d.pitch.0 * fit, d.pitch.1 * fit);
@@ -1099,9 +1149,6 @@ impl Sam {
         self.yaw_vel = 0.0;
         self.pitch_vel = 0.0;
     }
-    fn fitness(&self) -> f64 {
-        0.45 + 0.55 * self.health.clamp(0.0, 1.0)
-    }
     pub fn status(&self) -> String {
         let spec = self.kind.spec();
         let mut text = spec.name.to_string();
@@ -1118,7 +1165,10 @@ impl Sam {
                 let state = if self.ew_on { "ГЛУШИТ" } else if self.ew_lock { "остывает" } else { "готова" };
                 return format!("{text}: {state}, нагрев {:.0}%", self.heat * 100.0);
             }
-            SamKind::Radar => return format!("{text}: целей {}", self.own.len()),
+            SamKind::Radar => {
+                let broken = if self.comps.whole() { String::new() } else { format!(" [{}]", self.parts_text()) };
+                return format!("{text}: целей {}{broken}", self.own.len());
+            }
             SamKind::Light => return format!("{text}{}", if self.target.is_some() { ": в луче цель" } else { "" }),
             _ => {}
         }
@@ -1128,6 +1178,9 @@ impl Sam {
         if self.health < 1.0 {
             text += &format!(" ({:.0}%)", self.health * 100.0);
         }
+        if !self.comps.whole() {
+            text += &format!(" [{}]", self.parts_text());
+        }
         if self.reloading > 0 {
             text += &format!(" перезарядка {}с", self.reloading.div_ceil(20));
         } else {
@@ -1172,9 +1225,15 @@ pub struct Sim {
     pub tick: u64,
     pub kills: u32,
     pub hits: u32,
+    /// Drones that struck the land or a building short of their aim.
+    pub crashes: u32,
     pub launched: u32,
     /// Explosions damage the land (primed TNT through commands).
     pub damage: bool,
+    /// The seed: what falls to chance without the sequence (scan hits, damage to parts) is rolled from it.
+    seed: u64,
+    /// The air picture shows the true positions beside the tracks (a sandbox and analysis aid; changes no behaviour).
+    pub truth: bool,
     /// The shader draws fireballs: no glowing cubes.
     pub shader: bool,
     /// Air defence holds fire.
@@ -1201,6 +1260,10 @@ pub struct Sim {
     intel: ew::Intel,
     /// Night: guns need light (the mod sets it from the game's clock).
     pub night: bool,
+    /// The long fires at crash and impact points (#52).
+    pub fires: fires::Fires,
+    /// The world clock's time of day in ticks (the mod sets it; recordings keep it).
+    pub day_time: Option<u64>,
     /// Illumination flares in the sky, and the drones lit this tick.
     pub flares: Vec<lights::Flare>,
     pub lit: Vec<u32>,
@@ -1225,8 +1288,11 @@ impl Sim {
             tick: 0,
             kills: 0,
             hits: 0,
+            crashes: 0,
             launched: 0,
             damage: true,
+            seed: seed.wrapping_mul(0x2545_F491_4F6C_DD1D) | 1,
+            truth: false,
             shader: false,
             hold: false,
             horizons: HashMap::new(),
@@ -1241,6 +1307,8 @@ impl Sim {
             tally: record::Tally::default(),
             intel: ew::Intel::default(),
             night: false,
+            fires: fires::Fires::default(),
+            day_time: None,
             flares: Vec::new(),
             lit: Vec::new(),
         }
@@ -1289,6 +1357,8 @@ impl Sim {
     fn add_drone(&mut self, kind: DroneKind, from: DVec3, dir: DVec3, target: DVec3) {
         let id = self.id();
         let spec = kind.spec();
+        // Its navigation error: it flies to, and strikes at, a point off the aim it was given.
+        let target = target + self.aim_error(kind);
         let (vel, flight) = if spec.ballistic.is_some() {
             // An arc from `from` to `target` at the kind's horizontal speed.
             let flat = horizontal(target - from);
@@ -1357,6 +1427,7 @@ impl Sim {
         self.later.clear();
         self.flares.clear();
         self.lit.clear();
+        self.fires.extinguish();
     }
 
     /// One game tick.
@@ -1373,10 +1444,11 @@ impl Sim {
         self.update_sight(ground);
         self.step_lights(out);
         self.step_sams(out);
-        self.step_missiles(out);
+        self.step_missiles(ground, out);
         self.step_fx(ground, out);
         self.draw_targets(out);
         self.step_wrecks(out);
+        self.step_fires(ground, out);
         self.report_wave(out);
         self.record();
         let now = self.tick;
@@ -1394,10 +1466,14 @@ impl Sim {
         // Warheads that reached their aim (for the replays): drone, kind, where, TNT; and splits.
         let mut impacts: Vec<(u32, DroneKind, DVec3, u32)> = Vec::new();
         let mut splits: Vec<(u32, DVec3)> = Vec::new();
+        // Drones that struck the land or a building short of their aim: drone, kind, where, TNT.
+        let mut crashes: Vec<(u32, DroneKind, DVec3, u32)> = Vec::new();
         for d in &mut self.drones {
             d.age += 1;
             let spec = d.kind.spec();
             let below = ground.at(d.pos, now);
+            let from = d.pos;
+            ground.ahead(d.pos, d.vel, 20.0, now);
             // Near its aim it looks at the land there again: a platform or hilltop blown away
             // meanwhile, it goes for what is left below, not for the air where it stood.
             if d.flight != Flight::Falling
@@ -1412,11 +1488,15 @@ impl Sim {
                 d.vel *= 0.985;
                 d.spin += 0.35;
                 d.pos += d.vel;
+                let sweep = ground.sweep(from, d.pos, d.age <= 3, now);
+                if let Some((_, p)) = sweep.hit() {
+                    d.pos = p;
+                }
                 if self.rng.chance(0.5) {
                     out.particles("minecraft:large_smoke", d.pos, 0.2, DVec3::new(0.0, 0.05, 0.0), 0.02, 1);
                 }
                 out.particles("minecraft:flame", d.pos, 0.25, DVec3::ZERO, 0.02, 2);
-                if below.is_some_and(|g| d.pos.y <= g + 0.3) || d.age > 600 {
+                if sweep.hit().is_some() || ground.ground_hit(below, d.pos, 0.3, &sweep, now) || d.age > 600 {
                     // The wreck's warhead may still go off where it lands.
                     let warhead = if spec.decoy || !self.rng.chance(0.35) { 0 } else { spec.warhead.min(2) };
                     boom.push((d.pos, warhead, true));
@@ -1439,13 +1519,24 @@ impl Sim {
                     d.vel = turn(d.vel, d.target - d.pos, spec.turn) * sp;
                 }
                 d.pos += d.vel;
+                let sweep = ground.sweep(from, d.pos, d.age <= 3, now);
+                if let Some((_, p)) = sweep.hit() {
+                    d.pos = p;
+                }
                 let speed = d.vel.length();
+                let landed = sweep.hit().is_some() || ground.ground_hit(below, d.pos, 0.2, &sweep, now);
                 let hit = d.pos.distance(d.target) < speed.max(2.0)
-                    || below.is_some_and(|g| d.pos.y <= g + 0.2)
+                    || landed
                     || (d.vel.y < 0.0 && d.pos.y < d.target.y - 1.0 && horizontal(d.target - d.pos).length() < speed * 2.0)
                     || d.age > 4000;
                 if hit {
                     boom.push((d.pos, spec.warhead, false));
+                    // Into the land or a building short of its aim: a crash, not a hit.
+                    if landed && d.pos.distance(d.target) >= speed.max(2.0) + 6.0 {
+                        crashes.push((d.id, d.kind, d.pos, spec.warhead));
+                        removed.push(d.id);
+                        continue;
+                    }
                     impacts.push((d.id, d.kind, d.pos, spec.warhead));
                     removed.push(d.id);
                     self.hits += 1;
@@ -1546,10 +1637,22 @@ impl Sim {
             let speed = if d.flight == Flight::Dive { spec.speed * 1.35 } else { spec.speed };
             d.vel = new * speed;
             d.pos += d.vel;
+            let sweep = ground.sweep(from, d.pos, d.age <= 3, now);
+            if let Some((_, p)) = sweep.hit() {
+                d.pos = p;
+            }
             let at_target = d.pos.distance(d.target) < speed.max(1.5);
-            let in_ground = below.is_some_and(|g| d.pos.y <= g + 0.2);
+            let in_ground = sweep.hit().is_some() || ground.ground_hit(below, d.pos, 0.2, &sweep, now);
             if at_target || in_ground || d.age > 8000 {
                 boom.push((d.pos, spec.warhead, spec.decoy));
+                // Into the land or a building short of its aim: a crash, not a hit.
+                if in_ground && d.pos.distance(d.target) >= speed.max(1.5) + 3.0 {
+                    if !spec.decoy {
+                        crashes.push((d.id, d.kind, d.pos, spec.warhead));
+                    }
+                    removed.push(d.id);
+                    continue;
+                }
                 if !spec.decoy {
                     impacts.push((d.id, d.kind, d.pos, spec.warhead));
                 }
@@ -1580,6 +1683,17 @@ impl Sim {
         for (drone, pos) in splits {
             self.log(pos, record::EventKind::Split { drone });
         }
+        for (drone, kind, pos, tnt) in crashes {
+            self.crashes += 1;
+            let power = match tnt {
+                0 => 0,
+                1 | 2 => 1,
+                3..=5 => 2,
+                6 | 7 => 3,
+                _ => 4,
+            };
+            self.log(pos, record::EventKind::Crash { drone, kind, power });
+        }
         for (drone, kind, pos, tnt) in impacts {
             if let Some(sector) = self.drones.iter().find(|x| x.id == drone).map(|x| x.sector as usize) {
                 self.learn(sector, false);
@@ -1594,6 +1708,8 @@ impl Sim {
             let object = self.targets.iter().position(|t| t.distance(pos) < 16.0);
             let sam = self.sams.iter().enumerate().find(|(_, s)| s.alive() && s.pos.distance(pos) < 12.0).map(|(i, s)| (s.kind, i));
             self.log(pos, record::EventKind::Hit { drone, kind, power, object, sam });
+            let vel = self.drones.iter().find(|x| x.id == drone).map_or(DVec3::ZERO, |x| x.vel);
+            self.direct_hit(pos, vel, tnt, out);
         }
         for (pos, warhead, small) in boom {
             self.explode(pos, warhead, small, ground, player, out);
@@ -1797,18 +1913,20 @@ impl Sim {
                 retarget(&mut guns_on, sam.gun_target.take(), None);
                 continue;
             }
-            let fit = self.sams[i].fitness();
             {
                 let sam = &mut self.sams[i];
                 sam.cooldown = sam.cooldown.saturating_sub(1);
                 sam.gun_cooldown = sam.gun_cooldown.saturating_sub(1);
                 sam.flash = sam.flash.saturating_sub(1);
                 sam.recoil *= 0.6;
-                sam.dish = (sam.dish + 0.15) % TAU;
+                if sam.radar_up() {
+                    sam.dish = sam.beam;
+                }
+                sam.jam = sam.jam.saturating_sub(1);
                 if sam.reloading > 0 {
                     sam.reloading -= 1;
                     if sam.reloading == 0 {
-                        sam.missiles = spec.missile.as_ref().map_or(0, |m| m.magazine);
+                        sam.missiles = sam.cells();
                         sam.bursts = spec.gun.as_ref().map_or(0, |g| g.bursts);
                         out.sound("minecraft:block.piston.extend", sam.pos, 2.0, 0.6);
                     }
@@ -1830,23 +1948,27 @@ impl Sim {
             let pos = self.sams[i].pos;
             let roles = self.sams[i].roles;
             let (had_target, had_gun) = (self.sams[i].target, self.sams[i].gun_target);
+            let now = self.tick;
             let (target, gun_target) = {
-                let (seen, own) = (&self.sams[i].seen, &self.sams[i].own);
-                // The conditions are `why`'s, shared with the diagnostic.
-                let allowed = |d: &Drone| why::allowed(roles, seen, d);
+                let tracks = &self.sams[i].tracks;
+                // The conditions are `why`'s, shared with the diagnostic. A system knows its targets by their tracks:
+                // the forecast of the last measurement, never the true place.
+                let drone = |tr: &Track| drone_at.get(&tr.id).map(|&k| &self.drones[k]);
                 let claimed = |d: &Drone| why::claimed(d, &missile_on, had_target);
                 let needed = why::needed;
                 let target = spec.missile.as_ref().map(|load| {
-                    let in_reach = |d: &Drone, k: f64| why::in_reach(load.min, load.max, k, pos, d);
-                    let keep = had_target.filter(|t| {
-                        drone_at.get(t).is_some_and(|&k| allowed(&self.drones[k]) && in_reach(&self.drones[k], 1.1))
-                    });
+                    let ok = |tr: &Track, k: f64| {
+                        drone(tr).is_some_and(|d| why::allowed(roles, tr, now, d) && why::in_reach(load.min, load.max, k, pos, tr.est(now)))
+                    };
+                    let keep = had_target.filter(|t| tracks.iter().any(|tr| tr.id == *t && ok(tr, 1.1)));
                     keep.or_else(|| {
-                        self.drones
+                        tracks
                             .iter()
-                            .filter(|d| allowed(d) && in_reach(d, 1.0) && claimed(d) < needed(d))
-                            .max_by(|a, b| a.threat(pos).total_cmp(&b.threat(pos)))
-                            .map(|d| d.id)
+                            .filter(|tr| ok(tr, 1.0))
+                            .filter_map(|tr| drone(tr).map(|d| (tr, d)))
+                            .filter(|(_, d)| claimed(d) < needed(d))
+                            .max_by(|a, b| a.1.threat_at(pos, a.0.est(now)).total_cmp(&b.1.threat_at(pos, b.0.est(now))))
+                            .map(|(_, d)| d.id)
                     })
                 });
                 // Guns: the nearest, spread over the targets the other guns and missiles aren't on.
@@ -1854,12 +1976,13 @@ impl Sim {
                     let on_it = |d: &Drone| {
                         (guns_on.get(&d.id).copied().unwrap_or(0) - u32::from(had_gun == Some(d.id))) as f64
                     };
-                    self.drones
+                    tracks
                         .iter()
-                        .filter(|d| why::gun_candidate(roles, seen, own, gun.track, pos, d))
-                        .map(|d| {
+                        .filter_map(|tr| drone(tr).map(|d| (tr, d)))
+                        .filter(|(tr, d)| why::gun_candidate(roles, tr, now, gun.track, pos, d))
+                        .map(|(tr, d)| {
                             let busy = 1.0 + 2.0 * on_it(d) + if d.engaged > 0 { 1.5 } else { 0.0 };
-                            (d.pos.distance(pos) * busy, d.id)
+                            (tr.est(now).distance(pos) * busy, d.id)
                         })
                         .min_by(|a, b| a.0.total_cmp(&b.0))
                         .map(|(_, id)| id)
@@ -1883,18 +2006,23 @@ impl Sim {
             }
             let sam = &mut self.sams[i];
             // What the turret or launcher points at: guns first when a target is close.
-            let aim = sam.gun_target.or(sam.target).and_then(|t| drone_at.get(&t).map(|&k| &self.drones[k]));
+            let aim = sam
+                .gun_target
+                .or(sam.target)
+                .filter(|t| drone_at.contains_key(t))
+                .and_then(|t| sam.track(t))
+                .map(|tr| (tr.id, tr.est(now), tr.vel));
             sam.launched = sam.launched.saturating_sub(1);
             let Some(aim) = aim else {
                 // Out of missiles or of shells, and nothing to shoot: reload now (both, as a
                 // combined system's crew would), not only once both are spent.
-                let spent = (spec.missile.is_some() && sam.missiles == 0) || (spec.gun.is_some() && sam.bursts == 0);
+                let spent = (spec.missile.is_some() && sam.missiles == 0 && sam.part(Part::Launcher) > 0.0) || (spec.gun.is_some() && sam.bursts == 0);
                 if spent && sam.reloading == 0 && !sam.empty {
                     if logistics {
                         sam.empty = true;
                         ammo_waits += 1;
                     } else {
-                        sam.reloading = spec.reload
+                        sam.reloading = sam.reload_time()
                     }
                 }
                 sam.state = if sam.reloading > 0 {
@@ -1910,7 +2038,8 @@ impl Sim {
             };
             let (mount, _) = sam.mount();
             let lead_speed = spec.gun.as_ref().map_or(5.0, |g| g.shell);
-            let (lead, want_yaw, want_pitch) = why::aim_wants(mount, aim, lead_speed);
+            let (aim_id, aim_pos, aim_vel) = aim;
+            let (lead, want_yaw, want_pitch) = why::aim_wants(mount, aim_pos, aim_vel, lead_speed);
             let cells = matches!(spec.muzzle, Muzzle::Cells);
             match spec.family {
                 // Vertical launch: no aiming (the Tor's turret turns its radar to the target).
@@ -1933,7 +2062,7 @@ impl Sim {
                 SamState::Fire
             } else if !vertical && aim_error > 0.15 {
                 SamState::Slew
-            } else if aim.pos.distance(mount) < self::SamKind::range(sam.kind) {
+            } else if aim_pos.distance(mount) < self::SamKind::range(sam.kind) {
                 SamState::Lock
             } else {
                 SamState::Track
@@ -1941,8 +2070,16 @@ impl Sim {
             // Guns.
             if let (Some(gun), Some(gt)) = (&spec.gun, sam.gun_target) {
                 if let Some(t) = drone_at.get(&gt).map(|&k| &self.drones[k]) {
-                    let dist = t.pos.distance(mount);
-                    if why::gun_blocks(sam, aim.id, gt, aim_error, dist, gun.range) == 0 {
+                    let est = sam.track(gt).map_or(t.pos, |tr| tr.est(now));
+                    let dist = est.distance(mount);
+                    let mut blocks = why::gun_blocks(sam, aim_id, gt, aim_error, dist, gun.range, now);
+                    // A damaged gun jams now and then, for a while: the burst it was about to fire is lost.
+                    let wear = 1.0 - sam.part(Part::Gun);
+                    if blocks == 0 && wear > 0.0 && dice(self.seed, now, sam.id as u64, 77) < wear * 0.1 {
+                        sam.jam = 30 + (dice(self.seed, now, sam.id as u64, 78) * 90.0) as u32;
+                        blocks = why::JAMMED;
+                    }
+                    if blocks == 0 {
                         sam.gun_cooldown = 2;
                         sam.bursts -= 1;
                         sam.flash = 2;
@@ -1952,7 +2089,7 @@ impl Sim {
                         sam.empty = true;
                         ammo_waits += 1;
                     } else {
-                        sam.reloading = spec.reload
+                        sam.reloading = sam.reload_time()
                     }
                         }
                         let (_, rot) = sam.mount();
@@ -1979,7 +2116,9 @@ impl Sim {
                         }
                         // At night a gun sees what is lit (a searchlight, a flare) and little else.
                         let dark = if self.night && !self.lit.contains(&t.id) { lights::DARK_HITS } else { 1.0 };
-                        let p = gun.p * fit * dark / t.kind.spec().stealth * (1.0 - dist / (gun.range * 1.3)).max(0.35);
+                        // The aim point is the track's forecast: the farther it is from the truth, the more shells miss.
+                        let off = est.distance(t.pos);
+                        let p = gun.p * sam.gun_fit() * dark / (t.kind.spec().stealth * (1.0 + (off / 8.0).powi(2))) * (1.0 - dist / (gun.range * 1.3)).max(0.35);
                         if self.rng.chance(p) {
                             gun_hits.push((gt, sam.id));
                         } else {
@@ -1992,8 +2131,8 @@ impl Sim {
             if let (Some(load), Some(mt)) = (&spec.missile, sam.target) {
                 let ready = why::missile_blocks(sam) == 0;
                 // The missile turns after its boost, but the launcher must point near the target.
-                let t = drone_at.get(&mt).map(|&k| &self.drones[k]);
-                let aligned = why::missile_aligned(spec.family, sam.yaw, mount, t, aim.id, mt, aim_error);
+                let t = sam.track(mt).filter(|_| drone_at.contains_key(&mt)).map(|tr| tr.est(now));
+                let aligned = why::missile_aligned(spec.family, sam.yaw, mount, t, aim_id, mt, aim_error);
                 if ready && aligned {
                     let n = load.magazine - sam.missiles;
                     let (muzzle, dir) = sam.muzzle(n);
@@ -2014,7 +2153,7 @@ impl Sim {
                         sam.empty = true;
                         ammo_waits += 1;
                     } else {
-                        sam.reloading = spec.reload
+                        sam.reloading = sam.reload_time()
                     }
                     }
                 }
@@ -2061,10 +2200,12 @@ impl Sim {
 
     // ------------------------------------------------ interceptors
 
-    fn step_missiles(&mut self, out: &mut Out) {
+    fn step_missiles(&mut self, ground: &mut Ground, out: &mut Out) {
+        let now = self.tick;
         let mut done: Vec<(u32, Option<u32>, bool, u32)> = Vec::new(); // (missile, target, kill, sam)
         let (mut missed, mut expired, mut orphaned) = (0u32, 0u32, 0u32);
-        let sams_fit: HashMap<u32, f64> = self.sams.iter().map(|s| (s.id, s.fitness())).collect();
+        let mut blocked = 0u32;
+        let sams_fit: HashMap<u32, f64> = self.sams.iter().map(|s| (s.id, 1.0 - 0.3 * (1.0 - s.health.clamp(0.0, 1.0)))).collect();
         for m in &mut self.missiles {
             m.age += 1;
             let spec = m.kind.spec();
@@ -2091,13 +2232,16 @@ impl Sim {
             let before = m.pos;
             m.vel = new * speed;
             m.pos += m.vel;
+            // The first block on the way this tick; a fuse that goes off earlier along the way still counts.
+            ground.ahead(m.pos, m.vel, 10.0, now);
+            let world = ground.sweep(before, m.pos, m.age <= 12, now).hit();
             if let Some(t) = target {
                 // Closest approach this tick, both moving (fast targets cross a fuse in a tick).
                 let rel0 = (t.pos - t.vel) - before;
                 let rel1 = t.pos - m.pos;
                 let delta = rel1 - rel0;
                 let k = (-rel0.dot(delta) / delta.length_squared().max(1e-9)).clamp(0.0, 1.0);
-                if (rel0 + delta * k).length() < spec.fuse {
+                if (rel0 + delta * k).length() < spec.fuse && world.is_none_or(|(w, _)| k <= w) {
                     // A target faster than the interceptor is hard to hit.
                     let ratio = (spec.speed / t.vel.length().max(0.1)).min(1.0).powf(1.5);
                     let fit = sams_fit.get(&m.sam).copied().unwrap_or(1.0);
@@ -2107,6 +2251,13 @@ impl Sim {
                     continue;
                 }
             }
+            if let Some((_, p)) = world {
+                // The land or a building is in the way: the interceptor is lost there.
+                m.pos = p;
+                blocked += 1;
+                done.push((m.id, None, false, m.sam));
+                continue;
+            }
             if m.age > spec.life || (target.is_none() && m.age > 30) {
                 // Its target gone (shot down by another, or lost), or its life spent chasing one.
                 if target.is_none() {
@@ -2151,6 +2302,7 @@ impl Sim {
             t.missed += missed;
             t.expired += expired;
             t.orphaned += orphaned;
+            t.blocked += blocked;
         });
         for (mid, target, kill, sam) in done {
             if let Some(i) = self.missiles.iter().position(|m| m.id == mid) {

airdef-mod/src/sim/orders.rs

@@ -36,10 +36,10 @@ impl Sam {
 }
 
 impl Sim {
-    /// Orders unit `i` to drive to `to`. False for one that can't (a depot, a wreck).
+    /// Orders unit `i` to drive to `to`. False for one that can't (a depot, a wreck, failed running gear).
     pub fn order_move(&mut self, i: usize, to: DVec3) -> bool {
         let Some(sam) = self.sams.get_mut(i) else { return false };
-        if !sam.alive() || !sam.kind.mobile() {
+        if !sam.alive() || !sam.kind.mobile() || sam.drive_speed() <= 0.0 {
             return false;
         }
         sam.dest = Some(to);
@@ -75,6 +75,10 @@ impl Sim {
                     }
                 }
                 SamState::Moving => {
+                    // The running gear failed on the way: it stops where it is and deploys there.
+                    if sam.drive_speed() <= 0.0 {
+                        sam.dest = None;
+                    }
                     let Some(to) = sam.dest else {
                         sam.state = SamState::Deploying;
                         sam.march = sam.kind.march_ticks();
@@ -93,7 +97,7 @@ impl Sim {
                     sam.heading = slew(sam.heading, heading_of(flat), 0.06);
                     let ahead = DQuat::from_rotation_y(sam.heading) * DVec3::NEG_Z;
                     let turning = angle_diff(sam.heading, heading_of(flat)).abs();
-                    let step = SPEED * (1.0 - turning / std::f64::consts::PI).max(0.2);
+                    let step = SPEED * sam.drive_speed() * (1.0 - turning / std::f64::consts::PI).max(0.2);
                     let next = sam.pos + ahead * step;
                     let y = ground.at(next, now).unwrap_or(sam.pos.y);
                     sam.pos = DVec3::new(next.x, sam.pos.y + (y - sam.pos.y).clamp(-0.5, 0.5), next.z);

airdef-mod/src/sim/record.rs

@@ -39,6 +39,8 @@ pub enum EventKind {
     SamLost { sam: u32, kind: SamKind, index: usize },
     /// The Oreshnik's bus or a block splitting.
     Split { drone: u32 },
+    /// A drone's warhead went off against the land or a building short of its aim.
+    Crash { drone: u32, kind: DroneKind, power: u32 },
 }
 
 #[derive(Clone, Copy, Debug)]
@@ -61,6 +63,8 @@ pub struct Tally {
     pub tracks_lost: u32,
     /// Times a system ran dry and began waiting for a reload truck.
     pub ammo_waits: u32,
+    /// Interceptors lost against the land or a building on their way.
+    pub blocked: u32,
 }
 
 impl Tally {
@@ -71,6 +75,7 @@ impl Tally {
             orphaned: self.orphaned.saturating_sub(start.orphaned),
             tracks_lost: self.tracks_lost.saturating_sub(start.tracks_lost),
             ammo_waits: self.ammo_waits.saturating_sub(start.ammo_waits),
+            blocked: self.blocked.saturating_sub(start.blocked),
         }
     }
     /// The non-zero counts as a line, or nothing.
@@ -81,6 +86,7 @@ impl Tally {
             (self.orphaned, "ракет остались без цели"),
             (self.tracks_lost, "потерь трека"),
             (self.ammo_waits, "ожиданий БК"),
+            (self.blocked, "ракет разбились о препятствие"),
         ]
         .into_iter()
         .filter(|p| p.0 > 0)
@@ -104,10 +110,16 @@ pub struct Recording {
     /// The systems and objects as they stood: (id, kind, where).
     pub sams: Vec<(u32, SamKind, DVec3)>,
     pub objects: Vec<DVec3>,
+    /// The world clock's time of day (ticks) every `TIME_STEP` ticks of the recording, from its
+    /// start: replays show the sky of the raid, not the current one. Empty when the clock was unknown.
+    times: Vec<u64>,
     /// Ticks the sky has been clear.
     quiet: u32,
 }
 
+/// Ticks between the recording's clock samples.
+const TIME_STEP: u32 = 20;
+
 impl Track {
     /// Where it was at `t` (the recording's ticks, fractional), if it was.
     pub fn at(&self, origin: DVec3, t: f64) -> Option<DVec3> {
@@ -163,6 +175,7 @@ impl Recording {
             tally: Tally::default(),
             sams: sim.sams.iter().map(|s| (s.id, s.kind, s.pos)).collect(),
             objects: sim.targets.clone(),
+            times: Vec::new(),
             quiet: 0,
         }
     }
@@ -178,6 +191,19 @@ impl Recording {
             }
         }
     }
+    /// The time of day (ticks, 24000 a day) the world showed at the recording's tick `t`: the
+    /// clock as sampled, run on between samples at the pace it ran (a jump is a step), or None
+    /// when the clock was not known (the replay then shows the world's own time).
+    pub fn day_time(&self, t: f64) -> Option<u64> {
+        let k = (t.max(0.0) / TIME_STEP as f64).floor() as usize;
+        let i = k.min(self.times.len().checked_sub(1)?);
+        let a = self.times[i];
+        let into = if i == k { t.max(0.0) - (i as u32 * TIME_STEP) as f64 } else { 0.0 };
+        match self.times.get(i + 1) {
+            Some(&b) if b >= a && b - a <= 2 * TIME_STEP as u64 => Some(a + ((b - a) as f64 * into / TIME_STEP as f64) as u64),
+            _ => Some(a),
+        }
+    }
     pub fn track(&self, id: u32) -> Option<&Track> {
         self.index.get(&id).map(|&i| &self.tracks[i])
     }
@@ -205,6 +231,15 @@ impl Sim {
 
     /// Something worth a replay happened.
     pub(super) fn log(&mut self, pos: DVec3, kind: EventKind) {
+        match kind {
+            EventKind::Crash { power, .. } => self.ignite(pos, power, None),
+            EventKind::Hit { power, sam, .. } => {
+                let host = sam.and_then(|(_, i)| self.sams.get(i)).map(|s| s.id);
+                self.ignite(pos, power.max(1), host)
+            }
+            EventKind::SamLost { sam, .. } => self.ignite(pos, 2, Some(sam)),
+            _ => {}
+        }
         if let Some(r) = &mut self.rec {
             let at = r.len;
             if let EventKind::Kill { drone, .. } = kind
@@ -230,6 +265,12 @@ impl Sim {
             self.rec = Some(Recording::new(self.recordings, self));
         }
         let Some(r) = &mut self.rec else { return };
+        if r.len % TIME_STEP == 0
+            && let Some(dt) = self.day_time
+            && r.times.len() == (r.len / TIME_STEP) as usize
+        {
+            r.times.push(dt);
+        }
         if r.len % STEP == 0 {
             for d in &self.drones {
                 r.point(d.id, What::Drone(d.kind), d.pos);
@@ -304,6 +345,31 @@ impl Sim {
                 }
             }
         }
+        // Fires: what the events left burning (the flames dim and the smoke thickens with time).
+        let mut lit: Vec<(DVec3, f64)> = Vec::new();
+        for (k, e) in rec.events.iter().enumerate() {
+            let power = match e.kind {
+                EventKind::Crash { power, .. } => power,
+                EventKind::Hit { power, .. } => power.max(1),
+                EventKind::SamLost { .. } => 2,
+                _ => continue,
+            };
+            let age = t - e.at as f64;
+            // One fire where several events met.
+            if lit.iter().any(|(p, at)| p.distance(e.pos) < 6.0 && *at <= e.at as f64) {
+                continue;
+            }
+            lit.push((e.pos, e.at as f64));
+            let (flame, smoke) = fires::replay_fire(power, age);
+            let id = base + 0x00c0_0000 + k as u32 * PARTS;
+            if flame > 0.05 {
+                let wob = 1.0 + 0.15 * (age * 0.9 + k as f64).sin();
+                out.model(id, "airdef:flame", e.pos + DVec3::Y * 0.5, DQuat::from_rotation_y(age * 0.07), (flame as f64 * 0.8 * wob).max(0.05), true);
+            }
+            if smoke > 0.1 && (age as u64) % 3 == 0 {
+                out.particles("minecraft:large_smoke", e.pos + DVec3::Y, 0.8, DVec3::new(0.0, 0.1, 0.0), 0.03, 1 + (smoke * 2.0) as u32);
+            }
+        }
         // Blasts: a fireball growing and fading for 1.5 s after each.
         for (k, e) in rec.events.iter().enumerate() {
             let age = t - e.at as f64;
@@ -312,7 +378,7 @@ impl Sim {
             }
             let size = match e.kind {
                 EventKind::Kill { .. } => 3.5,
-                EventKind::Hit { power, .. } => [2.5, 4.5, 7.0, 10.0, 13.0][(power as usize).min(4)],
+                EventKind::Hit { power, .. } | EventKind::Crash { power, .. } => [2.5, 4.5, 7.0, 10.0, 13.0][(power as usize).min(4)],
                 EventKind::SamLost { .. } => 8.0,
                 EventKind::Split { .. } => 2.0,
             };

airdef-mod/src/sim/regress.rs

@@ -1,6 +1,7 @@
 //! Regression tests for the issues filed on Gitea (each names its issue).
 use super::*;
 use super::raid::Grid;
+use super::damage::MISS_RADIUS;
 
 // #1: [bug] Запросы рельефа голодают: часть направлений РЛС никогда не получает высоты
 #[test]
@@ -222,3 +223,327 @@ fn drive_arrives_without_overshoot() {
         assert!(left.abs() < 1e-9 && vel == 0.0);
     }
 }
+
+// #49: a direct hit by an armed drone destroys the system at once, not with a dent of its health
+#[test]
+fn armed_strike_on_a_system_destroys_it_at_once() {
+    let centre = DVec3::new(0.0, 70.0, 0.0);
+    let hull = 2.2 * SamKind::Patriot.spec().scale;
+    for kind in [DroneKind::Lancet, DroneKind::Shahed] {
+        let mut destroyed = 0;
+        for seed in 1..=40 {
+            let mut sim = Sim::new(seed);
+            let id = sim.id();
+            sim.sams.push(Sam::new(id, SamKind::Patriot, centre, 0.0));
+            let mut ground = Ground::default();
+            sim.add_drone(kind, DVec3::new(0.0, 120.0, 0.0), DVec3::NEG_Y, centre);
+            let mut out = Out::default();
+            let mut impact = None;
+            for _ in 0..400 {
+                sim.step(&mut ground, None, &mut out);
+                if let Some(b) = sim.blasts.first() {
+                    impact = Some(b.at);
+                    break;
+                }
+                if sim.drones.is_empty() {
+                    break;
+                }
+            }
+            let at = impact.expect("the strike must go off");
+            let inside = DVec3::new(at.x, 0.0, at.z).distance(DVec3::new(centre.x, 0.0, centre.z)) <= hull && at.y < centre.y + 3.0;
+            let dead = !sim.sams[0].alive();
+            if inside {
+                assert!(dead, "{kind:?} seed {seed} struck the hull at {at:?} but the system lives");
+            }
+            destroyed += dead as u32;
+        }
+        assert!(destroyed >= 30, "{kind:?}: only {destroyed}/40 direct strikes destroyed the system");
+    }
+}
+
+// #49: a near miss is only splash, an unarmed body is no direct hit, the top of the hull counts
+#[test]
+fn near_miss_and_unarmed_body_are_not_direct_hits() {
+    let mut sim = Sim::new(1);
+    let id = sim.id();
+    sim.sams.push(Sam::new(id, SamKind::Patriot, DVec3::new(0.0, 70.0, 0.0), 0.0));
+    let down = DVec3::new(0.0, -2.0, 0.0);
+    sim.direct_hit(DVec3::new(6.0, 71.0, 0.0), down, 3, &mut Out::default());
+    assert!(sim.sams[0].alive(), "a near miss six blocks off destroyed the system");
+    sim.direct_hit(DVec3::new(0.0, 71.0, 0.0), down, 0, &mut Out::default());
+    assert!(sim.sams[0].alive(), "an unarmed body destroyed the system");
+    sim.direct_hit(DVec3::new(0.0, 73.0, 0.0), down, 1, &mut Out::default());
+    assert!(!sim.sams[0].alive(), "an armed warhead into the top of the hull did not destroy the system");
+}
+
+// #59: a strike misses at a small, kind-specific rate; its scatter is the kind's CEP (half land within it)
+#[test]
+fn strike_scatter_matches_each_kinds_cep_and_miss_rate() {
+    const N: u64 = 5000;
+    for kind in DroneKind::ALL {
+        let mut sim = Sim::new(7);
+        let (cep, gross) = kind.accuracy();
+        let sigma = cep / (2.0 * std::f64::consts::LN_2).sqrt();
+        let expected = (1.0 - gross) * (-MISS_RADIUS * MISS_RADIUS / (2.0 * sigma * sigma)).exp() + gross;
+        let (mut misses, mut within, mut farthest) = (0u64, 0u64, 0.0f64);
+        for _ in 0..N {
+            let e = sim.aim_error(kind);
+            assert_eq!(e.y, 0.0);
+            let r = e.length();
+            within += (r <= cep) as u64;
+            if r > MISS_RADIUS {
+                misses += 1;
+                farthest = farthest.max(r);
+            }
+        }
+        let rate = misses as f64 / N as f64;
+        let half = within as f64 / N as f64;
+        assert!((rate - expected).abs() < 0.015, "{kind:?}: miss rate {rate:.4}, expected {expected:.4}");
+        assert!((0.005..=0.20).contains(&rate), "{kind:?}: miss rate {rate:.4} is not a small share (the IRBM bus is the loosest)");
+        assert!((half - 0.5 * (1.0 - gross)).abs() < 0.03, "{kind:?}: {half:.3} of strikes within the CEP {cep}");
+        assert!(farthest < MISS_RADIUS + 4.0 * cep, "{kind:?}: a miss {farthest:.2} blocks out, far from the aim");
+    }
+}
+
+// #59: the drone flies to its own error point and bursts there: the miss lands near the aim, by the CEP
+#[test]
+fn strikes_burst_near_their_aim_within_the_kinds_cep() {
+    let aim = DVec3::new(0.0, 70.0, 0.0);
+    for kind in [DroneKind::Shahed, DroneKind::Lancet] {
+        let cep = kind.accuracy().0;
+        let mut misses = 0;
+        for seed in 1..=60 {
+            let mut sim = Sim::new(seed);
+            let mut ground = Ground::default();
+            sim.add_drone(kind, DVec3::new(0.0, 120.0, 0.0), DVec3::NEG_Y, aim);
+            let mut out = Out::default();
+            let mut impact = None;
+            for _ in 0..400 {
+                sim.step(&mut ground, None, &mut out);
+                if let Some(b) = sim.blasts.first() {
+                    impact = Some(b.at);
+                    break;
+                }
+                if sim.drones.is_empty() {
+                    break;
+                }
+            }
+            let at = impact.expect("the strike must go off");
+            let off = DVec3::new(at.x - aim.x, 0.0, at.z - aim.z).length();
+            assert!(off < MISS_RADIUS + 4.0 * cep + 2.0, "{kind:?} seed {seed} burst {off:.2} blocks from its aim");
+            misses += (off > MISS_RADIUS) as u32;
+        }
+        assert!(misses <= 6, "{kind:?}: {misses}/60 strikes missed");
+    }
+}
+
+// ---- #42, #43: flights are swept against the blocks of the world (a synthetic world stands in for the game)
+
+/// Blocks from a function: `Some(solid)`, or `None` where there is no chunk.
+struct Blocks<F: Fn(i32, i32, i32) -> Option<bool>>(F);
+impl<F: Fn(i32, i32, i32) -> Option<bool>> world::WorldSource for Blocks<F> {
+    fn solid(&self, x: i32, y: i32, z: i32) -> Option<bool> {
+        (self.0)(x, y, z)
+    }
+}
+
+/// Reads the sections a flight along `a` to `b` needs, as the game would answer them over a few ticks.
+fn warm(ground: &mut Ground, src: &dyn world::WorldSource, a: DVec3, b: DVec3) {
+    for _ in 0..4 {
+        ground.world.sweep(a, b, false, 0);
+        let wanted = ground.world.take_wanted(0);
+        ground.world.serve(src, wanted, 0);
+    }
+}
+
+/// One tick of the drones with the game answering what was asked.
+fn fly(sim: &mut Sim, ground: &mut Ground, src: &dyn world::WorldSource) {
+    sim.tick += 1;
+    sim.step_drones(ground, None, &mut Out::default());
+    let wanted = ground.world.take_wanted(sim.tick);
+    ground.world.serve(src, wanted, sim.tick);
+}
+
+// #42: a drone that crosses a one-block wall in a tick explodes at the wall, and that is no hit on its aim
+#[test]
+fn fast_drone_must_not_cross_a_one_block_wall() {
+    let src = Blocks(|x, y, z| Some(y < 64 || (x == 3 && (64..141).contains(&y) && z.abs() < 50)));
+    let mut sim = Sim::new(1);
+    sim.damage = false;
+    let mut ground = Ground::default();
+    sim.add_drone(DroneKind::Zircon, DVec3::new(0.0, 100.0, 0.0), DVec3::X, DVec3::new(1000.0, 100.0, 0.0));
+    sim.drones[0].flight = Flight::Dive;
+    warm(&mut ground, &src, DVec3::new(0.0, 100.0, 0.0), DVec3::new(30.0, 100.0, 0.0));
+    fly(&mut sim, &mut ground, &src);
+    assert!(sim.drones.is_empty(), "crossed the wall in one tick");
+    let at = sim.blasts.first().expect("no blast").at;
+    assert!((at.x - 3.0).abs() < 0.05 && (at.y - 100.0).abs() < 1.5, "burst at {at:?}, not at the wall face x=3");
+    assert_eq!((sim.crashes, sim.hits), (1, 0), "a wall in the way is a crash, not a hit on the aim");
+    assert!(sim.replays.iter().chain(sim.rec.iter()).all(|r| r.events.iter().all(|e| !matches!(e.kind, record::EventKind::Hit { .. }))));
+}
+
+// #42: a drone flying into a hill side explodes at the face of the hill
+#[test]
+fn drone_flying_into_a_hill_explodes_at_its_face() {
+    // Flat at 64 to x=50, then a slope of 1:1.
+    let height = |x: i32| 64 + (x - 50).max(0);
+    let src = Blocks(move |x, y, _| Some(y < height(x)));
+    for kind in [DroneKind::Shahed, DroneKind::Zircon] {
+        let mut sim = Sim::new(3);
+        sim.damage = false;
+        let mut ground = Ground::default();
+        sim.add_drone(kind, DVec3::new(0.0, 80.0, 0.0), DVec3::X, DVec3::new(600.0, 80.0, 0.0));
+        sim.drones[0].flight = Flight::Dive;
+        for _ in 0..300 {
+            if sim.drones.is_empty() {
+                break;
+            }
+            fly(&mut sim, &mut ground, &src);
+        }
+        assert!(sim.drones.is_empty(), "{kind:?} flew on");
+        let at = sim.blasts.first().expect("no blast").at;
+        // The slope meets y=80 at x=66.
+        assert!(at.x > 62.0 && at.x < 67.5, "{kind:?} burst at {at:?}, not at the hill face (x~66)");
+        assert_eq!(sim.crashes, 1, "{kind:?}");
+    }
+}
+
+// #42: an interceptor cannot pass through a wall to its target, and does not kill it from behind the wall
+#[test]
+fn missile_cannot_pass_through_a_wall() {
+    let src = Blocks(|x, y, z| Some(y < 64 || (x == 3 && (64..141).contains(&y) && z.abs() < 50)));
+    let mut sim = Sim::new(1);
+    let mut ground = Ground::default();
+    // The target stands still just behind the wall, inside the fuse's reach.
+    sim.add_drone(DroneKind::Shahed, DVec3::new(8.5, 100.0, 0.0), DVec3::ZERO, DVec3::new(0.0, 100.0, 900.0));
+    sim.drones[0].vel = DVec3::ZERO;
+    sim.drones[0].engaged = 1;
+    let (target, id) = (sim.drones[0].id, sim.id());
+    sim.missiles.push(Missile { id, kind: MissileKind::Pac3, pos: DVec3::new(0.0, 100.0, 0.0), vel: DVec3::X * 3.0, target, sam: 0, age: 20 });
+    warm(&mut ground, &src, DVec3::new(0.0, 100.0, 0.0), DVec3::new(30.0, 100.0, 0.0));
+    sim.tick = 1;
+    sim.step_missiles(&mut ground, &mut Out::default());
+    assert!(sim.missiles.is_empty(), "the missile is still flying");
+    assert_eq!(sim.kills, 0, "a kill through the wall");
+    assert!(sim.drones[0].alive(), "the target died behind the wall");
+    assert_eq!(sim.drones[0].engaged, 0, "the target stays claimed by a missile that is gone");
+    assert_eq!(sim.tally.blocked, 1);
+    assert!(sim.blasts.iter().all(|b| b.at.x < 3.5), "burst behind the wall");
+}
+
+// #42, #43: a bridge deck above the flight is no ground under it
+#[test]
+fn flight_under_a_bridge_is_not_a_ground_hit() {
+    let src = Blocks(|_, y, _| Some(y < 64 || y == 140));
+    let mut sim = Sim::new(1);
+    sim.damage = false;
+    let mut ground = Ground::default();
+    // The height map knows only the deck: 141 everywhere.
+    ground.answer((-5..400).map(|x| (x, 0, 141)).collect(), 0);
+    sim.add_drone(DroneKind::Shahed, DVec3::new(0.0, 100.0, 0.0), DVec3::X, DVec3::new(2000.0, 100.0, 0.0));
+    warm(&mut ground, &src, DVec3::new(0.0, 100.0, 0.0), DVec3::new(300.0, 100.0, 0.0));
+    for _ in 0..40 {
+        fly(&mut sim, &mut ground, &src);
+    }
+    assert_eq!(sim.drones.len(), 1, "the deck above was taken for the ground");
+    assert_eq!(sim.crashes, 0);
+}
+
+// #43: unknown chunks and spent budgets are never air; changes and another world void the cache
+#[test]
+fn unknown_is_not_clear_and_changes_invalidate() {
+    let mut ground = Ground::default();
+    let (a, b) = (DVec3::new(0.5, 70.5, 0.5), DVec3::new(30.5, 70.5, 0.5));
+    // Nothing read yet: the segment is unknown and the sections are asked for.
+    assert!(matches!(ground.world.sweep(a, b, false, 1), world::Sweep::Unknown { .. }));
+    let asked = ground.world.take_wanted(1);
+    assert!(asked.contains(&(0, 4, 0)), "{asked:?}");
+    // The game has no chunk there: still unknown, not air.
+    let nothing = Blocks(|_, _, _| None);
+    ground.world.serve(&nothing, asked, 2);
+    assert!(matches!(ground.world.sweep(a, b, false, 3), world::Sweep::Unknown { .. }));
+    // A wall appears in a chunk that now is loaded: found after it is read again.
+    let wall = Blocks(|x, _, _| Some(x == 20));
+    for now in [70, 71, 72] {
+        ground.world.sweep(a, b, false, now);
+        let w = ground.world.take_wanted(now);
+        ground.world.serve(&wall, w, now);
+    }
+    let hit = ground.world.sweep(a, b, false, 73);
+    assert!(matches!(hit, world::Sweep::Hit { block: [20, 70, 0], normal: [-1, 0, 0], .. }), "{hit:?}");
+    // The wall is broken: the game says which section changed, and the next sweep asks again.
+    let open = Blocks(|_, _, _| Some(false));
+    ground.world.changed(7, false, &[(1, 4, 0)]);
+    assert!(matches!(ground.world.sweep(a, b, false, 74), world::Sweep::Hit { .. }), "stale data is used until the answer");
+    let w = ground.world.take_wanted(74);
+    assert!(w.contains(&(1, 4, 0)), "{w:?}");
+    ground.world.serve(&open, w, 75);
+    assert_eq!(ground.world.sweep(a, b, false, 76), world::Sweep::Clear);
+    // Another world: everything goes.
+    ground.world.changed(8, false, &[]);
+    assert!(ground.world.is_empty());
+}
+
+// #43: the same wall and tunnel fixtures answer alike by sweep and by sections, and the cache is bounded
+#[test]
+fn wall_and_tunnel_fixtures_agree() {
+    let tunnel = Blocks(|x, y, z| Some(y < 60 || (x == 10 && !(y == 70 && z == 0))));
+    let mut ground = Ground::default();
+    for z in [0.5, 1.5] {
+        let (a, b) = (DVec3::new(0.5, 70.5, z), DVec3::new(30.5, 70.5, z));
+        warm(&mut ground, &tunnel, a, b);
+        let r = ground.world.sweep(a, b, false, 1);
+        if z == 0.5 {
+            assert_eq!(r, world::Sweep::Clear, "the tunnel is open");
+        } else {
+            assert!(matches!(r, world::Sweep::Hit { block: [10, 70, 1], .. }), "{r:?}");
+        }
+    }
+    assert!(ground.world.bytes() < 64 * 1024);
+}
+
+// #57: a recording keeps the world clock of the raid, with jumps as steps.
+#[test]
+fn recordings_keep_the_time_of_day() {
+    let mut sim = Sim::new(1);
+    sim.day_time = Some(18000);
+    sim.add_drone(DroneKind::Geran3, DVec3::new(0.0, 80.0, 0.0), DVec3::Z, DVec3::new(0.0, 70.0, 500.0));
+    let mut g = Ground::default();
+    let mut out = Out::default();
+    for i in 0..100u64 {
+        sim.day_time = Some(if i < 50 { 18000 + i } else { 6000 + i });
+        sim.step(&mut g, None, &mut out);
+    }
+    let r = sim.rec.as_ref().unwrap();
+    assert_eq!(r.day_time(0.0), Some(18000 + sim_first(r)));
+    // The jump is a step, not a glide through the day.
+    for t in 0..r.len.min(100) {
+        let v = r.day_time(t as f64).unwrap();
+        assert!((18000..18060).contains(&v) || (6000..6110).contains(&v), "{t}: {v}");
+    }
+}
+
+fn sim_first(r: &record::Recording) -> u64 {
+    r.tracks.first().map_or(0, |t| t.first as u64)
+}
+
+// #52: a crash lights a fire; the oldest of too many dies down; water leaves steam only.
+#[test]
+fn fires_start_merge_and_are_limited() {
+    let mut sim = Sim::new(1);
+    sim.ignite(DVec3::new(0.0, 70.0, 0.0), 1, None);
+    sim.ignite(DVec3::new(2.0, 70.0, 0.0), 2, None);
+    assert_eq!(sim.fires.len(), 1, "one fire where two things fell");
+    assert!(sim.fires.list[0].size >= fires::size_for(2));
+    for i in 0..30 {
+        sim.tick += 10;
+        sim.ignite(DVec3::new(100.0 * (i + 1) as f64, 70.0, 0.0), 1, None);
+    }
+    let now = sim.tick;
+    // Past the limit the oldest are already dying down.
+    let healthy = sim.fires.list.iter().filter(|f| (now - f.start) + 160 < f.life as u64).count();
+    assert!(healthy <= fires::MAX, "{healthy}");
+    let (fl, sm) = fires::level(10.0, 3000.0);
+    assert!(fl > 0.0 && sm > 0.0);
+    assert_eq!(fires::level(3000.0, 3000.0).0, 0.0);
+}

airdef-mod/src/sim/sensor_tests.rs

@@ -0,0 +1,228 @@
+//! Radar scan cycles with ageing tracks (#46) and damage to a system's parts (#50).
+use super::sight::{swept, FORECAST_AGE};
+use super::*;
+
+fn flat() -> (Ground, Out) {
+    (Ground::default(), Out::default())
+}
+
+fn radar_at(sim: &mut Sim, kind: SamKind, x: f64) -> usize {
+    let id = sim.id();
+    sim.sams.push(Sam::new(id, kind, DVec3::new(x, 70.0, 0.0), 0.0));
+    sim.sams.len() - 1
+}
+
+/// A Shahed flying east along z = 40, from x = `from`, high enough to be above any horizon of the systems.
+fn drone_from(sim: &mut Sim, from: f64) -> u32 {
+    sim.add_drone(DroneKind::Shahed, DVec3::new(from, 95.0, 40.0), DVec3::X, DVec3::new(5000.0, 95.0, 40.0));
+    sim.drones.last().unwrap().id
+}
+
+// #46: the radar measures a target when the beam passes it; between passes its track stays where it was measured.
+#[test]
+fn a_radar_measures_once_a_turn_and_the_track_stays_put_between() {
+    let mut sim = Sim::new(5);
+    let (mut ground, mut out) = flat();
+    let r = radar_at(&mut sim, SamKind::Radar, 0.0);
+    let id = drone_from(&mut sim, -150.0);
+    let (mut seen_at, mut last) = (Vec::new(), None::<(u64, DVec3)>);
+    let mut stale_gap = 0.0f64;
+    for _ in 0..700 {
+        sim.step(&mut ground, None, &mut out);
+        let Some(t) = sim.sams[r].track(id).copied() else { continue };
+        match last {
+            Some((tick, pos)) if tick == t.tick => {
+                assert_eq!(pos, t.pos, "the track moved without a new measurement");
+                let d = sim.drones.iter().find(|d| d.id == id).unwrap();
+                stale_gap = stale_gap.max(d.pos.distance(t.pos));
+                if t.age(sim.tick) > FORECAST_AGE {
+                    assert!(t.forecast(sim.tick));
+                }
+            }
+            _ => seen_at.push(t.tick),
+        }
+        last = Some((t.tick, t.pos));
+    }
+    assert!(seen_at.len() >= 2, "measured {} times", seen_at.len());
+    // A turn of the early-warning radar is 140 ticks (less relative to a target that moves round it): never every tick.
+    assert!(seen_at.windows(2).all(|w| w[1] - w[0] >= 60), "{seen_at:?}");
+    assert!(stale_gap > 20.0, "the track never fell behind the target ({stale_gap})");
+}
+
+#[test]
+fn a_beam_crossing_north_between_ticks_still_passes_a_target_there() {
+    let tau = std::f64::consts::TAU;
+    assert!(swept(0.01, tau - 0.05, 0.1));
+    assert!(swept(tau - 0.02, tau - 0.05, 0.1));
+    assert!(!swept(0.2, tau - 0.05, 0.1));
+    assert!(!swept(tau - 0.1, tau - 0.05, 0.1));
+}
+
+#[test]
+fn two_radars_have_their_own_phase_and_the_network_keeps_the_age() {
+    let mut sim = Sim::new(7);
+    let (mut ground, mut out) = flat();
+    let a = radar_at(&mut sim, SamKind::Radar, 0.0);
+    let b = radar_at(&mut sim, SamKind::Radar, 500.0);
+    let n = radar_at(&mut sim, SamKind::P1sun, 250.0);
+    assert_ne!(sim.sams[a].beam, sim.sams[b].beam, "radars start at different phases");
+    let id = drone_from(&mut sim, -50.0);
+    let mut relayed = 0;
+    for _ in 0..800 {
+        sim.step(&mut ground, None, &mut out);
+        let own = |s: usize| sim.sams[s].track(id).map_or(0, |t| t.own_tick);
+        let Some(t) = sim.sams[n].track(id) else { continue };
+        relayed += 1;
+        assert_eq!(t.own_tick, 0, "a relayed measurement is not the receiver's own");
+        assert!(t.tick <= own(a).max(own(b)), "the network made a track fresher than any measurement");
+        if own(a).max(own(b)) > 0 {
+            assert_eq!(t.tick, own(a).max(own(b)), "the network holds the freshest measurement");
+        }
+    }
+    assert!(relayed > 100, "the network never passed a track ({relayed})");
+}
+
+#[test]
+fn a_lock_measures_every_tick_and_a_dead_radar_stops_the_feed() {
+    let mut sim = Sim::new(3);
+    let (mut ground, mut out) = flat();
+    let p = radar_at(&mut sim, SamKind::Pantsir, 0.0);
+    let net = radar_at(&mut sim, SamKind::P1sun, 100.0);
+    let id = drone_from(&mut sim, -190.0);
+    let mut locked = 0;
+    for _ in 0..600 {
+        sim.step(&mut ground, None, &mut out);
+        if sim.sams[p].target == Some(id)
+            && let Some(t) = sim.sams[p].track(id)
+            && t.age(sim.tick) <= 1
+            && t.locked
+        {
+            locked += 1;
+        }
+    }
+    assert!(locked > 5, "no fire-control lock ({locked})");
+    // The radar is destroyed: the network's track is no longer renewed.
+    let newest = sim.sams[net].tracks.iter().map(|t| t.tick).max();
+    sim.sams[p].health = 0.0;
+    let drones = sim.drones.iter().filter(|d| d.alive()).count();
+    for _ in 0..40 {
+        sim.step(&mut ground, None, &mut out);
+    }
+    assert!(sim.sams[p].tracks.is_empty() && sim.sams[p].seen.is_empty());
+    if drones > 0 {
+        assert!(sim.sams[net].tracks.iter().map(|t| t.tick).max() <= newest, "a dead radar still renewed a track");
+    }
+}
+
+#[test]
+fn a_failed_radar_gives_no_own_tracks_but_the_network_still_feeds_it() {
+    let mut sim = Sim::new(9);
+    let (mut ground, mut out) = flat();
+    let p = radar_at(&mut sim, SamKind::Patriot, 0.0);
+    let early = radar_at(&mut sim, SamKind::Radar, 120.0);
+    let id = drone_from(&mut sim, -150.0);
+    sim.sams[p].comps.0[Part::Sensor as usize] = 0.0;
+    for _ in 0..500 {
+        sim.step(&mut ground, None, &mut out);
+    }
+    assert!(!sim.sams[p].radar_up());
+    assert!(sim.sams[p].own.is_empty(), "a failed radar measured something");
+    assert!(sim.sams[p].track(id).is_some(), "the network should still feed the system");
+    // Without its link it is blind.
+    sim.sams[p].comps.0[Part::Comms as usize] = 0.0;
+    sim.sams[p].tracks.clear();
+    for _ in 0..200 {
+        sim.step(&mut ground, None, &mut out);
+    }
+    assert!(sim.sams[p].tracks.is_empty(), "no link, no network tracks");
+    assert!(sim.sams[early].own.len() >= sim.sams[p].own.len());
+}
+
+// #50: a blast hurts the parts nearest to it.
+#[test]
+fn a_blast_from_behind_hurts_the_link_a_blast_from_the_front_the_drive() {
+    let at = DVec3::new(0.0, 70.0, 0.0);
+    let hurt = |dz: f64| {
+        let mut sim = Sim::new(4);
+        let id = sim.id();
+        sim.sams.push(Sam::new(id, SamKind::Patriot, at, 0.0));
+        let mut out = Out::default();
+        sim.blast_damage(at + DVec3::new(0.0, 3.0, dz), 2, &mut out);
+        assert!(sim.sams[0].alive());
+        let c = sim.sams[0].comps;
+        (1.0 - c.get(Part::Comms), 1.0 - c.get(Part::Mount), 1.0 - c.get(Part::Sensor))
+    };
+    let (back_comms, back_mount, _) = hurt(6.0);
+    let (front_comms, front_mount, _) = hurt(-6.0);
+    assert!(back_comms > back_mount, "behind: link {back_comms} drive {back_mount}");
+    assert!(front_mount > front_comms, "front: link {front_comms} drive {front_mount}");
+}
+
+#[test]
+fn a_close_blast_can_leave_a_firing_but_immobile_system() {
+    // Over many blasts at moderate range some leave the system able to fire and unable to drive.
+    let mut found = false;
+    for seed in 0..60 {
+        let mut sim = Sim::new(seed);
+        let id = sim.id();
+        sim.sams.push(Sam::new(id, SamKind::Pantsir, DVec3::new(0.0, 70.0, 0.0), 0.0));
+        let mut out = Out::default();
+        sim.tick = seed;
+        sim.blast_damage(DVec3::new(0.0, 69.0, 6.0 + seed as f64 * 0.06), 3, &mut out);
+        let s = &sim.sams[0];
+        if s.alive() && s.part(Part::Tracks) <= 0.0 && s.part(Part::Launcher) > 0.0 && s.part(Part::Gun) > 0.0 {
+            assert!(!sim.order_move(0, DVec3::new(300.0, 70.0, 0.0)), "failed running gear must refuse a march");
+            assert!(why::missile_blocks(&sim.sams[0]) & why::LAUNCHER_DOWN == 0);
+            assert!(sim.why(0).iter().any(|c| c.text.contains("ходовая отказала")), "{:?}", sim.why(0).iter().map(|c| &c.text).collect::<Vec<_>>());
+            found = true;
+            break;
+        }
+    }
+    assert!(found, "no seed left it firing but immobile");
+}
+
+#[test]
+fn failed_parts_block_what_they_serve_and_repair_restores_them() {
+    let mut sim = Sim::new(2);
+    let g = radar_at(&mut sim, SamKind::Gepard, 0.0);
+    let p = radar_at(&mut sim, SamKind::Patriot, 400.0);
+    sim.sams[g].comps.0[Part::Gun as usize] = 0.0;
+    assert!(!sim.sams[g].gun_up());
+    assert!(why::gun_blocks(&sim.sams[g], 1, 1, 0.0, 10.0, 90.0, 0) & why::JAMMED != 0);
+    sim.sams[p].comps.0[Part::Launcher as usize] = 0.0;
+    assert!(why::missile_blocks(&sim.sams[p]) & why::LAUNCHER_DOWN != 0);
+    // A worn launcher: fewer cells, a longer reload.
+    sim.sams[p].comps.0[Part::Launcher as usize] = 0.3;
+    sim.sams[p].fit_cells();
+    let full = Sam::new(0, SamKind::Patriot, DVec3::ZERO, 0.0);
+    assert!(sim.sams[p].cells() < full.cells());
+    assert!(sim.sams[p].missiles <= sim.sams[p].cells());
+    assert!(sim.sams[p].reload_time() > full.reload_time());
+    // A worn mount turns slower, a failed one not at all.
+    sim.sams[p].comps.0[Part::Mount as usize] = 0.0;
+    assert_eq!(sim.sams[p].drive_fit(), 0.0);
+    sim.sams[p].comps.0[Part::Tracks as usize] = 0.0;
+    assert_eq!(sim.repair(), 2, "both damaged systems are counted");
+    assert!(sim.sams.iter().all(|s| s.comps.whole() && s.cells() == s.kind.spec().missile.as_ref().map_or(0, |m| m.magazine)));
+    assert!(sim.later.is_empty(), "repair must not leave cook-offs behind");
+    assert!(sim.order_move(p, DVec3::new(500.0, 70.0, 0.0)));
+}
+
+#[test]
+fn the_same_seed_rolls_the_same_scan_and_damage() {
+    let run = || {
+        let mut sim = Sim::new(11);
+        let (mut ground, mut out) = flat();
+        let r = radar_at(&mut sim, SamKind::Radar, 0.0);
+        let id = drone_from(&mut sim, -150.0);
+        let mut ticks = Vec::new();
+        for _ in 0..500 {
+            sim.step(&mut ground, None, &mut out);
+            if let Some(t) = sim.sams[r].track(id) {
+                ticks.push(t.tick);
+            }
+        }
+        ticks
+    };
+    assert_eq!(run(), run());
+}

airdef-mod/src/sim/sight.rs

@@ -3,6 +3,17 @@
 //! (over the curve of the earth, scaled to the game's distances), and the land
 //! hides what flies behind hills and woods: each system keeps its horizon, the
 //! highest the land rises seen from its antenna, ray by ray round it.
+//!
+//! A radar does not know where everything is all the time. Its beam sweeps round
+//! (a period by the kind of radar; an electronic one also revisits what it holds
+//! more often), a target is measured when the beam passes it, with a chance that
+//! falls with range and size, and the measurement is kept as a *track*: where it
+//! was and how fast it went then, and when. Between measurements the track is
+//! carried on by that velocity (a forecast, shown as one), and after three missed
+//! scans it is dropped. A fire-control lock on a target the system is engaging is
+//! a dedicated channel: it measures every tick while the target is in reach and in
+//! sight. The network passes tracks with the age of their measurement; relaying
+//! makes none of them fresher.
 use super::*;
 
 /// Rays round a radar, and blocks between the land's samples along them.
@@ -10,6 +21,13 @@ const RAYS: usize = 48;
 const STEP: f64 = 16.0;
 /// How far units share their tracks (the network's data links).
 pub(super) const LINK: f64 = 1500.0;
+/// A launcher fires on a track no older than this (ticks); a gun needs its own radar's, newer than `GUN_AGE`.
+pub(super) const MISSILE_AGE: u64 = 120;
+pub(super) const GUN_AGE: u64 = 3;
+/// A gun takes a target its radar measured this recently (then the lock refreshes it every tick).
+pub(super) const GUN_PICK_AGE: u64 = 40;
+/// A track older than this is shown as a forecast.
+pub const FORECAST_AGE: u64 = 20;
 /// Radio horizon: `HORIZON * (√mast + √height)` blocks.
 const HORIZON: f64 = 35.0;
 /// Anything this near is seen (and heard), whatever hides it.
@@ -70,13 +88,144 @@ pub(super) fn reach(sam: &Sam, kind: DroneKind, height: f64) -> f64 {
     if spec.sensor <= 0.0 {
         return 0.0;
     }
-    let radar = spec.sensor * sam.fitness() * kind.rcs().powf(0.25);
+    let radar = spec.sensor * sam.radar_fit() * kind.rcs().powf(0.25);
     let horizon = HORIZON * (spec.mast.sqrt() + height.max(0.0).sqrt());
     radar.min(horizon).max(NEAR)
 }
 
+/// How a kind's radar looks round.
+pub(super) struct Scan {
+    /// Ticks for the beam to go round.
+    pub period: u32,
+    /// An electronic radar: what it holds it revisits at once a third of the period, between the beam's passes.
+    pub agile: bool,
+}
+
+impl SamKind {
+    pub(super) fn scan(self) -> Scan {
+        let (period, agile) = match self {
+            SamKind::Patriot => (30, true),
+            SamKind::S400 => (36, true),
+            SamKind::S500 => (24, true),
+            SamKind::IrisT | SamKind::Nasams => (40, true),
+            SamKind::Buk => (50, false),
+            SamKind::Tor | SamKind::Pantsir => (40, false),
+            SamKind::Gepard => (50, false),
+            // The early-warning radar: a big antenna turning slowly.
+            SamKind::Radar => (140, false),
+            _ => (40, false),
+        };
+        Scan { period, agile }
+    }
+}
+
+/// How well a track says what it is.
+#[derive(Clone, Copy, PartialEq, Eq, Debug)]
+pub enum Ident {
+    /// One measurement: something is there.
+    Unknown,
+    /// Measured again: a drone or missile by how it flies.
+    Probable,
+    /// Held by a lock or by several measurements.
+    Confirmed,
+}
+
+impl Ident {
+    pub fn name(self) -> &'static str {
+        match self {
+            Ident::Unknown => "неопознана",
+            Ident::Probable => "предположительно воздушная цель",
+            Ident::Confirmed => "подтверждена",
+        }
+    }
+}
+
+/// What a system knows of one target: the last measurement, not the target itself.
+#[derive(Clone, Copy, Debug)]
+pub struct Track {
+    pub id: u32,
+    /// Where it was and how it went when last measured (blocks, blocks a tick).
+    pub pos: DVec3,
+    pub vel: DVec3,
+    /// When that was, and when this system's own radar last measured it (0: never, the network's only).
+    pub tick: u64,
+    pub own_tick: u64,
+    /// Ticks the track lives without a new measurement.
+    pub ttl: u32,
+    pub hits: u8,
+    /// The last own measurement came from a fire-control lock.
+    pub locked: bool,
+}
+
+impl Track {
+    pub fn age(&self, now: u64) -> u64 {
+        now.saturating_sub(self.tick)
+    }
+    /// Where the target should be by now, carrying the last measurement on: the forecast, not a measurement.
+    pub fn est(&self, now: u64) -> DVec3 {
+        self.pos + self.vel * self.age(now) as f64
+    }
+    pub fn forecast(&self, now: u64) -> bool {
+        self.age(now) > FORECAST_AGE
+    }
+    /// Own radar measured it within `age` ticks.
+    pub fn own_within(&self, now: u64, age: u64) -> bool {
+        self.own_tick > 0 && now.saturating_sub(self.own_tick) <= age
+    }
+    pub fn ident(&self) -> Ident {
+        match self.hits {
+            0 | 1 => Ident::Unknown,
+            2 => Ident::Probable,
+            _ => Ident::Confirmed,
+        }
+    }
+    /// How far the forecast may be off, blocks: grows with the age.
+    pub fn uncertainty(&self, now: u64) -> f64 {
+        1.0 + self.age(now) as f64 * (0.05 + self.vel.length() * 0.1)
+    }
+}
+
+impl Sam {
+    /// Ticks for its beam to go round (longer when the radar is damaged).
+    pub(super) fn scan_ticks(&self) -> f64 {
+        self.kind.scan().period as f64 / self.radar_fit().max(0.2)
+    }
+    /// Its own radar works: it has one, it is not failed and the unit is deployed.
+    pub fn radar_up(&self) -> bool {
+        self.alive() && !self.moving() && self.kind.spec().sensor > 0.0 && self.part(Part::Sensor) > 0.0
+    }
+    pub fn track(&self, id: u32) -> Option<&Track> {
+        self.tracks.iter().find(|t| t.id == id)
+    }
+}
+
+/// Whether a beam that moved from `from` by `w` radians this tick passed `bearing` (all angles taken round 2π,
+/// so a beam crossing north between two ticks still passes a target there).
+pub(super) fn swept(bearing: f64, from: f64, w: f64) -> bool {
+    (bearing - from).rem_euclid(TAU) < w
+}
+
+/// A new measurement into a list of tracks (the index maps ids to places): a fresher one replaces an older.
+fn merge(tracks: &mut Vec<Track>, index: &mut HashMap<u32, usize>, t: Track) {
+    match index.get(&t.id) {
+        Some(&k) => {
+            let mine = &mut tracks[k];
+            if t.tick > mine.tick {
+                let (own_tick, locked) = (mine.own_tick, if t.own_tick > 0 { t.locked } else { mine.locked });
+                let hits = mine.hits.max(t.hits);
+                *mine = Track { own_tick: if t.own_tick > 0 { t.own_tick } else { own_tick }, hits, locked, ..t };
+            }
+        }
+        None => {
+            index.insert(t.id, tracks.len());
+            tracks.push(t);
+        }
+    }
+}
+
 impl Sim {
-    /// Rebuilds the systems' horizons in turn, and what each radar holds now.
+    /// Rebuilds the systems' horizons in turn, then lets each radar's beam pass the sky: new measurements
+    /// into the tracks, old tracks out, and the network's tracks shared.
     pub(super) fn update_sight(&mut self, ground: &mut Ground) {
         let now = self.tick;
         // One horizon every few ticks: the land answers come in over time.
@@ -95,44 +244,108 @@ impl Sim {
         // Each drone's height over the land under it (or over the systems' ground, unknown).
         let heights: Vec<Option<f64>> =
             self.drones.iter().map(|d| ground.at(d.pos, now).map(|g| d.pos.y - g)).collect();
+        let drone_at: HashMap<u32, usize> = self.drones.iter().enumerate().map(|(k, d)| (d.id, k)).collect();
+        let seed = self.seed;
+        let mut index: HashMap<u32, usize> = HashMap::new();
         for sam in &mut self.sams {
-            sam.seen.clear();
-            sam.own.clear();
-            if !sam.alive() || sam.kind.spec().sensor <= 0.0 || sam.moving() {
+            // A track of a drone that is gone is dropped (the kill is seen), so is one not renewed for its time.
+            sam.tracks.retain(|t| now - t.tick <= t.ttl as u64 && drone_at.get(&t.id).is_some_and(|&k| self.drones[k].alive()));
+            if !sam.alive() || sam.moving() {
+                sam.tracks.clear();
                 continue;
             }
+            if !sam.radar_up() {
+                continue;
+            }
+            index.clear();
+            index.extend(sam.tracks.iter().enumerate().map(|(k, t)| (t.id, k)));
+            let spec = sam.kind.spec();
+            let scan = sam.kind.scan();
+            let period = sam.scan_ticks();
+            let w = TAU / period;
+            let (b0, ttl) = (sam.beam, ((period * 3.0) as u32).max(60));
+            sam.beam = (b0 + w) % TAU;
             let at = antenna(sam);
             let horizon = self.horizons.get(&sam.id);
+            let mut fresh: Vec<Track> = Vec::new();
             for (d, h) in self.drones.iter().zip(&heights) {
                 if !d.alive() {
                     continue;
                 }
-                let dist = d.pos.distance(at);
+                let rel = d.pos - at;
+                let dist = rel.length();
+                if dist > spec.sensor * 1.2 {
+                    continue;
+                }
+                let locked = sam.target == Some(d.id) || sam.gun_target == Some(d.id);
+                let held = index.get(&d.id).map(|&k| sam.tracks[k]);
+                // The beam passes its bearing this tick (the angle wraps at 2π: the difference is taken round).
+                let in_beam = swept(rel.x.atan2(-rel.z), b0, w);
+                let revisit = scan.agile && held.is_some_and(|t| t.own_tick > 0 && now - t.own_tick >= (period / 3.0) as u64);
+                if !(in_beam || locked || revisit) {
+                    continue;
+                }
                 let height = h.unwrap_or(d.pos.y - sam.pos.y);
-                if dist > reach(sam, d.kind, height) {
+                let reach = reach(sam, d.kind, height);
+                if dist > reach || (dist > NEAR && horizon.is_some_and(|hz| hz.hides(at, d.pos))) {
                     continue;
                 }
-                if dist > NEAR && horizon.is_some_and(|hz| hz.hides(at, d.pos)) {
+                let key = (sam.id as u64) << 32 | d.id as u64;
+                // A target in the beam is measured with a chance that falls towards the edge of reach and
+                // with the target's stealth; one the radar already follows is lost only now and then.
+                let p = if locked || revisit {
+                    0.985
+                } else {
+                    ((0.97 - 0.5 * (dist / reach).powi(3)) / d.kind.spec().stealth.sqrt()).clamp(0.05, 0.97)
+                };
+                if dist > NEAR && dice(seed, now, key, 0) >= p {
                     continue;
                 }
-                sam.own.push(d.id);
+                let sigma = if locked { 0.3 } else { 0.8 + dist * 0.004 };
+                let noise = DVec3::new(dice(seed, now, key, 1) - 0.5, (dice(seed, now, key, 2) - 0.5) * 0.5, dice(seed, now, key, 3) - 0.5) * 2.0 * sigma;
+                fresh.push(Track {
+                    id: d.id,
+                    pos: d.pos + noise,
+                    vel: d.vel,
+                    tick: now,
+                    own_tick: now,
+                    ttl,
+                    hits: held.map_or(1, |t| t.hits.saturating_add(1)),
+                    locked,
+                });
+            }
+            for t in fresh {
+                merge(&mut sam.tracks, &mut index, t);
             }
         }
-        // The network: every unit gets the tracks of the radars within data-link range.
-        let tracks: Vec<(DVec3, Vec<u32>)> =
-            self.sams.iter().filter(|s| !s.own.is_empty()).map(|s| (s.pos, s.own.clone())).collect();
-        // Merged in the radars' order, each track once: a set marks what is in already.
-        let mut have: std::collections::HashSet<u32> = std::collections::HashSet::new();
+        // The network: every unit gets the tracks the radars within data-link range measured themselves,
+        // with the time they were measured: a relayed track is never fresher than its measurement.
+        let shared: Vec<(u32, DVec3, f64, Vec<Track>)> = self
+            .sams
+            .iter()
+            .filter(|s| s.alive() && !s.moving() && s.link_range() > 0.0)
+            .map(|s| (s.id, s.pos, s.link_range(), s.tracks.iter().filter(|t| t.own_tick == t.tick).copied().collect::<Vec<_>>()))
+            .filter(|s| !s.3.is_empty())
+            .collect();
         for sam in &mut self.sams {
-            sam.seen.clone_from(&sam.own);
-            if !sam.alive() || sam.moving() || !sam.kind.armed() {
-                continue;
+            if sam.alive() && !sam.moving() && sam.kind.armed() && sam.link_range() > 0.0 && !shared.is_empty() {
+                index.clear();
+                index.extend(sam.tracks.iter().enumerate().map(|(k, t)| (t.id, k)));
+                let mine = sam.link_range();
+                for (id, at, range, tracks) in &shared {
+                    if *id != sam.id && at.distance(sam.pos) <= range.min(mine) {
+                        for t in tracks {
+                            merge(&mut sam.tracks, &mut index, Track { own_tick: 0, ..*t });
+                        }
+                    }
+                }
             }
-            have.clear();
-            have.extend(sam.own.iter().copied());
-            for (at, ids) in &tracks {
-                if at.distance(sam.pos) <= LINK {
-                    sam.seen.extend(ids.iter().copied().filter(|id| have.insert(*id)));
+            sam.seen.clear();
+            sam.own.clear();
+            for t in &sam.tracks {
+                sam.seen.push(t.id);
+                if t.own_within(now, t.ttl as u64) {
+                    sam.own.push(t.id);
                 }
             }
         }
@@ -142,4 +355,15 @@ impl Sim {
     pub fn tracked(&self, id: u32) -> bool {
         self.sams.iter().any(|s| s.seen.contains(&id))
     }
+
+    /// The freshest track of each drone any system holds: the air picture.
+    pub fn picture(&self) -> HashMap<u32, Track> {
+        let mut best: HashMap<u32, Track> = HashMap::new();
+        for t in self.sams.iter().flat_map(|s| s.tracks.iter()) {
+            if best.get(&t.id).is_none_or(|b| t.tick > b.tick) {
+                best.insert(t.id, *t);
+            }
+        }
+        best
+    }
 }

airdef-mod/src/sim/why.rs

@@ -11,29 +11,32 @@ use super::*;
 pub(super) const DEAD: u8 = 1;
 pub(super) const ROLE: u8 = 2;
 pub(super) const UNSEEN: u8 = 4;
+/// Its track is older than a launcher fires on.
+pub(super) const STALE: u8 = 8;
 
-pub(super) fn target_blocks(roles: u8, seen: &[u32], d: &Drone) -> u8 {
+pub(super) fn target_blocks(roles: u8, track: Option<&Track>, now: u64, d: &Drone) -> u8 {
     (if d.alive() { 0 } else { DEAD })
         | (if roles & d.kind.spec().class.bit() != 0 { 0 } else { ROLE })
-        | (if seen.contains(&d.id) { 0 } else { UNSEEN })
+        | (if track.is_some() { 0 } else { UNSEEN })
+        | (if track.is_some_and(|t| t.age(now) > sight::MISSILE_AGE) { STALE } else { 0 })
 }
 
-/// Alive, of a class the system engages, and on its picture (own radar or the network's).
-pub(super) fn allowed(roles: u8, seen: &[u32], d: &Drone) -> bool {
-    target_blocks(roles, seen, d) == 0
+/// Alive, of a class the system engages, and on its picture (own radar or the network's), fresh enough.
+pub(super) fn allowed(roles: u8, track: &Track, now: u64, d: &Drone) -> bool {
+    target_blocks(roles, Some(track), now, d) == 0
 }
 
 pub(super) const TOO_CLOSE: u8 = 1;
 pub(super) const TOO_FAR: u8 = 2;
 
 /// Missile range: `min` to `max * k` (a target already held may stray to 1.1 × max).
-pub(super) fn reach_blocks(min: f64, max: f64, k: f64, pos: DVec3, d: &Drone) -> u8 {
-    let dist = d.pos.distance(pos);
+pub(super) fn reach_blocks(min: f64, max: f64, k: f64, pos: DVec3, at: DVec3) -> u8 {
+    let dist = at.distance(pos);
     (if dist >= min { 0 } else { TOO_CLOSE }) | (if dist < max * k { 0 } else { TOO_FAR })
 }
 
-pub(super) fn in_reach(min: f64, max: f64, k: f64, pos: DVec3, d: &Drone) -> bool {
-    reach_blocks(min, max, k, pos, d) == 0
+pub(super) fn in_reach(min: f64, max: f64, k: f64, pos: DVec3, at: DVec3) -> bool {
+    reach_blocks(min, max, k, pos, at) == 0
 }
 
 /// Interceptors a target has or will have: in flight, and other systems' launchers on it.
@@ -47,9 +50,10 @@ pub(super) fn needed(d: &Drone) -> u32 {
     if d.kind.spec().class == Class::Ballistic { 2 } else { 1 }
 }
 
-/// A gun's candidates: held by the system's own radar and within the gun's tracking range.
-pub(super) fn gun_candidate(roles: u8, seen: &[u32], own: &[u32], track: f64, pos: DVec3, d: &Drone) -> bool {
-    allowed(roles, seen, d) && own.contains(&d.id) && d.pos.distance(pos) < track
+/// A gun's candidates: measured by the system's own radar a moment ago and within the gun's tracking range
+/// (by the track's forecast, not the target's true place).
+pub(super) fn gun_candidate(roles: u8, track: &Track, now: u64, gun_track: f64, pos: DVec3, d: &Drone) -> bool {
+    allowed(roles, track, now, d) && track.own_within(now, sight::GUN_PICK_AGE) && track.est(now).distance(pos) < gun_track
 }
 
 /// How many systems have each drone as their missile target and as their gun target.
@@ -66,8 +70,8 @@ pub(super) fn engagement_counts(sams: &[Sam]) -> (HashMap<u32, u32>, HashMap<u32
 // ---------------------------------------------------------------- aiming
 
 /// Where the lead point is and the yaw and pitch that point the mount at it.
-pub(super) fn aim_wants(mount: DVec3, aim: &Drone, lead_speed: f64) -> (DVec3, f64, f64) {
-    let lead = aim.pos + aim.vel * (aim.pos.distance(mount) / lead_speed);
+pub(super) fn aim_wants(mount: DVec3, at: DVec3, vel: DVec3, lead_speed: f64) -> (DVec3, f64, f64) {
+    let lead = at + vel * (at.distance(mount) / lead_speed);
     let to = lead - mount;
     let want_yaw = heading_of(to);
     let want_pitch = (to.y / to.length().max(0.01)).asin().clamp(-0.1, 1.45);
@@ -88,19 +92,22 @@ pub(super) fn aim_error(family: Family, yaw: f64, pitch: f64, want_yaw: f64, wan
 pub(super) const COOLDOWN: u8 = 1;
 pub(super) const RELOADING: u8 = 2;
 pub(super) const NO_ROUNDS: u8 = 4;
+/// The launcher has failed.
+pub(super) const LAUNCHER_DOWN: u8 = 8;
 
 /// What keeps a loaded launcher from firing now (aim aside).
 pub(super) fn missile_blocks(s: &Sam) -> u8 {
-    (if s.cooldown == 0 { 0 } else { COOLDOWN })
+    (if s.part(Part::Launcher) > 0.0 { 0 } else { LAUNCHER_DOWN })
+        | (if s.cooldown == 0 { 0 } else { COOLDOWN })
         | (if s.reloading == 0 { 0 } else { RELOADING })
         | (if s.missiles > 0 { 0 } else { NO_ROUNDS })
 }
 
 /// The launcher points near enough: a trainable one only by its training, a turret by its
 /// whole aim at this target, the vertical ones need nothing.
-pub(super) fn missile_aligned(family: Family, yaw: f64, mount: DVec3, t: Option<&Drone>, aim_id: u32, mt: u32, aim_error: f64) -> bool {
+pub(super) fn missile_aligned(family: Family, yaw: f64, mount: DVec3, t: Option<DVec3>, aim_id: u32, mt: u32, aim_error: f64) -> bool {
     match family {
-        Family::Trainable => t.is_some_and(|t| angle_diff(yaw, heading_of(t.pos - mount)).abs() < 0.15),
+        Family::Trainable => t.is_some_and(|t| angle_diff(yaw, heading_of(t - mount)).abs() < 0.15),
         Family::Turret => aim_id == mt && aim_error < 0.15,
         _ => true,
     }
@@ -109,11 +116,17 @@ pub(super) fn missile_aligned(family: Family, yaw: f64, mount: DVec3, t: Option<
 pub(super) const NOT_AIMED: u8 = 8;
 pub(super) const AIM_ERROR: u8 = 16;
 pub(super) const OUT_OF_RANGE: u8 = 32;
+/// The gun is jammed (for a while, or failed).
+pub(super) const JAMMED: u8 = 64;
+/// Its radar has no fresh measurement of the target.
+pub(super) const NO_LOCK: u8 = 128;
 
 /// What keeps a gun from firing now: the turret on another target, not yet laid, out of range,
 /// and the gun's own cooldown, reload and shells (`COOLDOWN`, `RELOADING`, `NO_ROUNDS` bits).
-pub(super) fn gun_blocks(s: &Sam, aim_id: u32, gt: u32, aim_error: f64, dist: f64, range: f64) -> u8 {
+pub(super) fn gun_blocks(s: &Sam, aim_id: u32, gt: u32, aim_error: f64, dist: f64, range: f64, now: u64) -> u8 {
     (if aim_id == gt { 0 } else { NOT_AIMED })
+        | (if s.gun_up() { 0 } else { JAMMED })
+        | (if s.track(gt).is_some_and(|t| t.own_within(now, sight::GUN_AGE)) { 0 } else { NO_LOCK })
         | (if aim_error < 0.1 { 0 } else { AIM_ERROR })
         | (if dist < range { 0 } else { OUT_OF_RANGE })
         | (if s.gun_cooldown == 0 { 0 } else { COOLDOWN })
@@ -160,9 +173,38 @@ impl Sim {
         let logistics = self.logistics();
         let (missile_on, guns_on) = engagement_counts(&self.sams);
         let alive = self.drones.iter().filter(|d| d.alive()).count();
+        let now = self.tick;
         let seen = self.drones.iter().filter(|d| d.alive() && sam.seen.contains(&d.id)).count();
         let own = self.drones.iter().filter(|d| d.alive() && sam.own.contains(&d.id)).count();
         v.push(check(alive > 0, format!("в небе {alive}, на картине {seen} (своя РЛС {own}, остальные по сети)")));
+        // The parts: what is worn or failed and what it costs.
+        if !sam.comps.whole() {
+            v.push(check(false, format!("узлы: {}", sam.parts_text())));
+        }
+        for p in Part::ALL {
+            if !p.on(sam.kind) || sam.part_state(p) == PartState::Ok {
+                continue;
+            }
+            let failed = sam.part_state(p) == PartState::Failed;
+            let effect = match (p, failed) {
+                (Part::Sensor, true) => "РЛС отказала: своих измерений нет, стволы не стреляют, ракеты — по данным сети".to_string(),
+                (Part::Sensor, false) => format!("РЛС повреждена: дальность {:.0}%, обзор вдвое реже при худшем", sam.radar_fit() * 100.0),
+                (Part::Mount, true) => format!("привод наведения заклинил: стоит на {:.0}°, не доворачивается", sam.yaw.to_degrees().rem_euclid(360.0)),
+                (Part::Mount, false) => format!("привод наведения повреждён: поворот {:.0}% от нормы", sam.drive_fit() * 100.0),
+                (Part::Launcher, true) => "пусковая отказала: пуски невозможны".to_string(),
+                (Part::Launcher, false) => format!("пусковая повреждена: {} ячеек из {}, перезарядка {:.0} с", sam.cells(), spec.missile.as_ref().map_or(0, |m| m.magazine), sam.reload_time() as f64 / 20.0),
+                (Part::Gun, true) => "орудие заклинило: не стреляет".to_string(),
+                (Part::Gun, false) => format!("орудие повреждено: меткость {:.0}%, заклинивает", sam.gun_fit() * 100.0),
+                (Part::Tracks, true) => "ходовая отказала: на марш не выйдет".to_string(),
+                (Part::Tracks, false) => format!("ходовая повреждена: скорость марша {:.0}%", sam.drive_speed() * 100.0),
+                (Part::Comms, true) => "связь отказала: сети нет, цели только свои".to_string(),
+                (Part::Comms, false) => format!("связь повреждена: линия {:.0} м", sam.link_range()),
+            };
+            v.push(check(false, effect));
+        }
+        if sam.jam > 0 {
+            v.push(check(false, format!("орудие заклинило, ещё {:.1} с", sam.jam as f64 / 20.0)));
+        }
         let drone_at = |id: u32| self.drones.iter().find(|d| d.id == id);
         let subject = sam.target.or(sam.gun_target).and_then(drone_at).or_else(|| {
             self.drones
@@ -175,24 +217,42 @@ impl Sim {
             return v;
         };
         let held = sam.target == Some(t.id) || sam.gun_target == Some(t.id);
-        let dist = t.pos.distance(sam.pos);
+        let dist = sam.track(t.id).map_or(t.pos, |tr| tr.est(self.tick)).distance(sam.pos);
         v.push(check(
             true,
             format!("цель: {} {}, {}", t.kind.spec().name, if held { "(сопровождается)" } else { "(самая опасная)" }, crate::panel::distance(dist)),
         ));
-        let blocks = target_blocks(sam.roles, &sam.seen, t);
+        let track = sam.track(t.id);
+        let blocks = target_blocks(sam.roles, track, now, t);
+        // Where the system believes the target is: its track's forecast (the true place only when it has no track).
+        let est = track.map_or(t.pos, |tr| tr.est(now));
+        let evel = track.map_or(t.vel, |tr| tr.vel);
         v.push(check(
             blocks & ROLE == 0,
             format!("роль: {} {} [{}]", t.kind.spec().class.name(), if blocks & ROLE == 0 { "в ролях" } else { "не в ролях" }, roles_text(sam.roles)),
         ));
-        let detect = match (sam.own.contains(&t.id), sam.seen.contains(&t.id)) {
-            (true, _) => "обнаружена своей РЛС",
-            (false, true) => "видна только по сети (стволы не стреляют)",
-            _ => "не обнаружена ни своей РЛС, ни сетью",
+        let detect = match (track, sam.own.contains(&t.id)) {
+            (Some(tr), own) => {
+                let kind = if own { "своей РЛС" } else { "по сети (стволы не стреляют)" };
+                let age = tr.age(now) as f64 / 20.0;
+                let lock = if tr.own_within(now, sight::GUN_AGE) && tr.locked { ", захват" } else { "" };
+                let how = if tr.forecast(now) { format!("прогноз ±{:.0} м", tr.uncertainty(now)) } else { "измерение".to_string() };
+                format!("трек {kind}: {}, возраст {age:.1} с, {how}{lock}, {}", tr.ident().name(), if blocks & STALE != 0 { "устарел для пуска" } else { "годен для пуска" })
+            }
+            _ => "не обнаружена ни своей РЛС, ни сетью".to_string(),
         };
-        v.push(check(blocks & UNSEEN == 0, detect));
-        let fit = sam.fitness();
-        v.push(check(fit >= 0.9, format!("состояние {:.0}%: поворот и точность {:.0}%", sam.health * 100.0, fit * 100.0)));
+        v.push(check(blocks & (UNSEEN | STALE) == 0, detect));
+        if sam.kind.spec().sensor > 0.0 {
+            let period = sam.scan_ticks();
+            v.push(check(
+                sam.radar_up(),
+                if sam.radar_up() {
+                    format!("обзор: оборот {:.1} с{}, луч на {:.0}°", period / 20.0, if sam.kind.scan().agile { ", электронный, цели в треке чаще" } else { "" }, sam.beam.to_degrees())
+                } else {
+                    "обзор: РЛС не работает".to_string()
+                },
+            ));
+        }
         // Ammunition and its supply.
         let mut rounds = String::new();
         if let Some(load) = &spec.missile {
@@ -211,12 +271,12 @@ impl Sim {
         v.push(check(sam.reloading == 0 && !sam.empty && (sam.missiles > 0 || sam.bursts > 0), format!("{rounds}— {supply}")));
         let mount = sam.mount().0;
         let lead_speed = spec.gun.as_ref().map_or(5.0, |g| g.shell);
-        let (_, want_yaw, want_pitch) = aim_wants(mount, t, lead_speed);
+        let (_, want_yaw, want_pitch) = aim_wants(mount, est, evel, lead_speed);
         let err = aim_error(spec.family, sam.yaw, sam.pitch, want_yaw, want_pitch);
         let vertical = spec.family == Family::Vertical;
         let mut fires = false;
         if let Some(load) = &spec.missile {
-            let reach = reach_blocks(load.min, load.max, 1.0, sam.pos, t);
+            let reach = reach_blocks(load.min, load.max, 1.0, sam.pos, est);
             v.push(check(
                 reach == 0,
                 format!(
@@ -241,15 +301,18 @@ impl Sim {
             if mb & NO_ROUNDS != 0 {
                 why.push("нет ракет".to_string());
             }
+            if mb & LAUNCHER_DOWN != 0 {
+                why.push("пусковая отказала".to_string());
+            }
             v.push(check(mb == 0, if mb == 0 { "пусковая готова".to_string() } else { format!("пусковая не готова: {}", why.join(", ")) }));
-            let aligned = missile_aligned(spec.family, sam.yaw, mount, Some(t), t.id, t.id, err);
+            let aligned = missile_aligned(spec.family, sam.yaw, mount, Some(est), t.id, t.id, err);
             let turn = if vertical { "вертикальный старт" } else { "доворот" };
             v.push(check(aligned, format!("{turn}: ошибка наведения {:.0}°{}", err.to_degrees(), if aligned { "" } else { " — ещё доворачивается" })));
             fires |= reach == 0 && free < need && mb == 0 && aligned && blocks == 0;
         }
         if let Some(gun) = &spec.gun {
             let on_it = guns_on.get(&t.id).copied().unwrap_or(0) - u32::from(sam.gun_target == Some(t.id));
-            let cand = gun_candidate(sam.roles, &sam.seen, &sam.own, gun.track, sam.pos, t);
+            let cand = track.is_some_and(|tr| gun_candidate(sam.roles, tr, now, gun.track, sam.pos, t));
             v.push(check(
                 cand,
                 format!(
@@ -259,7 +322,7 @@ impl Sim {
                     if cand { "" } else { " — вне сопровождения (нужна своя РЛС)" }
                 ),
             ));
-            let gb = gun_blocks(sam, t.id, t.id, err, mount.distance(t.pos), gun.range);
+            let gb = gun_blocks(sam, t.id, t.id, err, mount.distance(est), gun.range, now);
             let mut why = Vec::new();
             for (bit, name) in [
                 (AIM_ERROR, format!("орудие ещё наводится ({:.0}°)", err.to_degrees())),
@@ -267,6 +330,8 @@ impl Sim {
                 (COOLDOWN, "пауза между очередями".to_string()),
                 (RELOADING, "перезарядка".to_string()),
                 (NO_ROUNDS, "нет снарядов".to_string()),
+                (JAMMED, "орудие заклинило".to_string()),
+                (NO_LOCK, "нет свежего захвата своей РЛС".to_string()),
             ] {
                 if gb & bit != 0 {
                     why.push(name);

airdef-mod/src/sim/world.rs

@@ -0,0 +1,399 @@
+//! What the game's blocks are to the simulation (issues #42, #43): a cache of
+//! 16-block sections answered by `render.sections` (a bit per block that
+//! stops a projectile), a swept segment through it, and the bookkeeping that
+//! keeps the questions few: the sections along a flight asked for ahead of
+//! time, at most 64 a tick, nearest need first; changes of the world marking
+//! sections stale; a bounded cache. A chunk the game doesn't have answers
+//! `Unknown`, which is never the same as air: the callers fall back to the
+//! height of the land there and the counters say how often.
+use glam::DVec3;
+use std::collections::{HashMap, HashSet};
+
+/// A section: block coordinates divided by 16.
+pub type Sec = (i32, i32, i32);
+
+/// Sections asked in one tick (the game's budget).
+pub const PER_TICK: usize = 64;
+/// Sections kept; the least recently used go first beyond it.
+const MAX_SECTIONS: usize = 12_000;
+/// Ticks before an unanswered or unknown section is asked again.
+const RETRY: u64 = 60;
+/// Longest stretch of a flight asked for ahead, in blocks.
+const AHEAD_MAX: f64 = 192.0;
+/// Questions waiting: more are dropped (they are asked again when needed).
+const QUEUE_MAX: usize = 512;
+
+/// What a section holds, as the game answered.
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub enum Fill {
+    /// The game has no such chunk.
+    Unknown,
+    Empty,
+    Full,
+    /// 512 bytes, one bit per block, index `(y & 15) * 256 + (z & 15) * 16 + (x & 15)`.
+    Mixed(Box<[u8; 512]>),
+}
+
+/// An answer for a section, as the game gives it.
+pub struct SectionAnswer {
+    pub sec: Sec,
+    pub fill: Fill,
+}
+
+struct Entry {
+    fill: Fill,
+    /// A block changed (or may have) since it was read: asked again when next used.
+    stale: bool,
+    /// The tick it was last used in a sweep.
+    used: u64,
+    /// The tick it was answered.
+    since: u64,
+}
+
+/// How a swept segment ended.
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub enum Sweep {
+    /// Every block along it is known and none stops it.
+    Clear,
+    /// The first solid block: where the segment meets it, which way the face looks, and the block.
+    Hit { t: f64, point: DVec3, normal: [i32; 3], block: [i32; 3] },
+    /// The walk reached blocks the game doesn't know (before any solid one), `t` of the way.
+    Unknown { t: f64 },
+}
+
+impl Sweep {
+    pub fn hit(&self) -> Option<(f64, DVec3)> {
+        match *self {
+            Sweep::Hit { t, point, .. } => Some((t, point)),
+            _ => None,
+        }
+    }
+}
+
+/// Counters for the report: questions, unknowns, memory, cost.
+#[derive(Clone, Copy, Default, Debug)]
+pub struct WorldStats {
+    pub sweeps: u64,
+    pub cells: u64,
+    pub hits: u64,
+    pub unknown_sweeps: u64,
+    pub sections_asked: u64,
+    pub sections_answered: u64,
+    pub sections_unknown: u64,
+    pub invalidated: u64,
+    pub evicted: u64,
+    pub world_changes: u64,
+}
+
+#[derive(Default)]
+pub struct WorldCache {
+    secs: HashMap<Sec, Entry>,
+    urgent: Vec<Sec>,
+    ahead: Vec<Sec>,
+    queued: HashSet<Sec>,
+    /// Sections asked, and when.
+    asked: HashMap<Sec, u64>,
+    epoch: u32,
+    pub stats: WorldStats,
+}
+
+fn sec_of(x: i32, y: i32, z: i32) -> Sec {
+    (x >> 4, y >> 4, z >> 4)
+}
+
+impl WorldCache {
+    /// Memory the cached sections hold, about.
+    pub fn bytes(&self) -> usize {
+        self.secs
+            .values()
+            .map(|e| 48 + if matches!(e.fill, Fill::Mixed(_)) { 512 } else { 0 })
+            .sum()
+    }
+    pub fn len(&self) -> usize {
+        self.secs.len()
+    }
+    pub fn is_empty(&self) -> bool {
+        self.secs.is_empty()
+    }
+    /// One line for the report.
+    pub fn text(&self) -> String {
+        let s = &self.stats;
+        format!(
+            "мир: {} секций ({} КБ), запросов {}, неизвестно {}, лучей {} (ударов {}, неизв. {}), клеток {}",
+            self.len(),
+            self.bytes() / 1024,
+            s.sections_asked,
+            s.sections_unknown,
+            s.sweeps,
+            s.hits,
+            s.unknown_sweeps,
+            s.cells
+        )
+    }
+
+    /// The game's note of changes: another world voids everything; changed
+    /// sections (or too many to say) are read again when next used.
+    pub fn changed(&mut self, epoch: u32, overflow: bool, sections: &[Sec]) {
+        if epoch != self.epoch {
+            if self.epoch != 0 {
+                self.secs.clear();
+                self.urgent.clear();
+                self.ahead.clear();
+                self.queued.clear();
+                self.asked.clear();
+            }
+            self.epoch = epoch;
+        }
+        if overflow {
+            for e in self.secs.values_mut() {
+                e.stale = true;
+            }
+            self.stats.invalidated += self.secs.len() as u64;
+        }
+        for s in sections {
+            if let Some(e) = self.secs.get_mut(s) {
+                e.stale = true;
+                self.stats.invalidated += 1;
+            }
+        }
+        self.stats.world_changes += sections.len() as u64;
+    }
+
+    /// An explosion is about to change the land: the sections round it are read again.
+    pub fn touched(&mut self, at: DVec3, radius: f64) {
+        let lo = sec_of((at.x - radius).floor() as i32, (at.y - radius).floor() as i32, (at.z - radius).floor() as i32);
+        let hi = sec_of((at.x + radius).floor() as i32, (at.y + radius).floor() as i32, (at.z + radius).floor() as i32);
+        for x in lo.0..=hi.0 {
+            for y in lo.1..=hi.1 {
+                for z in lo.2..=hi.2 {
+                    if let Some(e) = self.secs.get_mut(&(x, y, z)) {
+                        e.stale = true;
+                    }
+                }
+            }
+        }
+    }
+
+    pub fn answer(&mut self, answers: Vec<SectionAnswer>, now: u64) {
+        for a in answers {
+            self.asked.remove(&a.sec);
+            self.stats.sections_answered += 1;
+            if a.fill == Fill::Unknown {
+                self.stats.sections_unknown += 1;
+            }
+            self.secs.insert(a.sec, Entry { fill: a.fill, stale: false, used: now, since: now });
+        }
+        if self.secs.len() > MAX_SECTIONS {
+            // Whatever wasn't used for a minute goes; if that's not enough, the older half.
+            self.secs.retain(|_, e| now.saturating_sub(e.used) < 1200);
+            if self.secs.len() > MAX_SECTIONS {
+                let mut used: Vec<u64> = self.secs.values().map(|e| e.used).collect();
+                used.sort_unstable();
+                let cut = used[used.len() / 2];
+                self.secs.retain(|_, e| e.used >= cut);
+            }
+            self.stats.evicted += 1;
+        }
+        // Forget questions the game never answered, so they can be asked again.
+        if now % 64 == 0 {
+            self.asked.retain(|_, t| now.saturating_sub(*t) < RETRY);
+        }
+    }
+
+    /// The sections to ask this tick (at most [`PER_TICK`]): the ones a sweep
+    /// needed first, then those along flights.
+    pub fn take_wanted(&mut self, now: u64) -> Vec<Sec> {
+        let mut out = Vec::new();
+        for list in [&mut self.urgent, &mut self.ahead] {
+            let room = PER_TICK - out.len();
+            let n = room.min(list.len());
+            out.extend(list.drain(..n));
+        }
+        for s in &out {
+            self.queued.remove(s);
+            self.asked.insert(*s, now);
+        }
+        self.stats.sections_asked += out.len() as u64;
+        out
+    }
+
+    fn want(&mut self, s: Sec, urgent: bool, now: u64) {
+        if self.queued.contains(&s) || self.asked.get(&s).is_some_and(|&t| now.saturating_sub(t) < RETRY) {
+            return;
+        }
+        if self.urgent.len() + self.ahead.len() >= QUEUE_MAX {
+            return;
+        }
+        if urgent {
+            self.urgent.push(s);
+        } else {
+            self.ahead.push(s);
+        }
+        self.queued.insert(s);
+    }
+
+    /// Asks for the sections along a flight from `pos` at `vel` a tick, `ticks` ahead.
+    pub fn look_ahead(&mut self, pos: DVec3, vel: DVec3, ticks: f64, now: u64) {
+        let mut d = vel * ticks;
+        let len = d.length();
+        if len < 1e-6 {
+            return;
+        }
+        if len > AHEAD_MAX {
+            d *= AHEAD_MAX / len;
+        }
+        // A section at a time along the segment (a section is 16 wide: half-section steps meet each).
+        let steps = (d.length() / 8.0).ceil().max(1.0) as i32;
+        let mut last = None;
+        for i in 0..=steps {
+            let p = pos + d * (i as f64 / steps as f64);
+            let s = sec_of(p.x.floor() as i32, p.y.floor() as i32, p.z.floor() as i32);
+            if last == Some(s) {
+                continue;
+            }
+            last = Some(s);
+            self.touch(s, false, now);
+        }
+    }
+
+    /// Touches a section the way a sweep or a look needs it: used now, and
+    /// asked again when stale or (after a while) unknown.
+    fn touch(&mut self, s: Sec, urgent: bool, now: u64) -> bool {
+        let Some(e) = self.secs.get_mut(&s) else {
+            self.want(s, urgent, now);
+            return false;
+        };
+        e.used = now;
+        let refresh = e.stale || (e.fill == Fill::Unknown && now.saturating_sub(e.since) >= RETRY);
+        if refresh {
+            self.want(s, urgent, now);
+        }
+        true
+    }
+
+    /// Whether the block at `(x, y, z)` stops a projectile: `None` where the
+    /// game hasn't said. `last` is the section just touched.
+    fn solid(&mut self, last: &mut Option<Sec>, x: i32, y: i32, z: i32, now: u64) -> Option<bool> {
+        let s = sec_of(x, y, z);
+        if *last != Some(s) {
+            *last = Some(s);
+            self.touch(s, true, now);
+        }
+        match &self.secs.get(&s)?.fill {
+            Fill::Unknown => None,
+            Fill::Empty => Some(false),
+            Fill::Full => Some(true),
+            Fill::Mixed(bits) => {
+                let i = ((y & 15) << 8 | (z & 15) << 4 | (x & 15)) as usize;
+                Some(bits[i >> 3] >> (i & 7) & 1 != 0)
+            }
+        }
+    }
+
+    /// Whether the block is known to hold no solid block, with the sky above it
+    /// in view: used to tell a fluid surface from a roof.
+    pub fn is_known_open(&mut self, x: i32, y: i32, z: i32, now: u64) -> bool {
+        self.solid(&mut None, x, y, z, now) == Some(false)
+    }
+
+    /// Whether the block is known to be solid.
+    pub fn is_known_solid(&mut self, x: i32, y: i32, z: i32, now: u64) -> bool {
+        self.solid(&mut None, x, y, z, now) == Some(true)
+    }
+
+    /// The first solid block along `a` to `b`, by walking the blocks it
+    /// crosses; `skip_start` ignores the block it starts in (a launch from a
+    /// pad that is part of the land).
+    pub fn sweep(&mut self, a: DVec3, b: DVec3, skip_start: bool, now: u64) -> Sweep {
+        self.stats.sweeps += 1;
+        let d = b - a;
+        let mut pos = [a.x.floor() as i32, a.y.floor() as i32, a.z.floor() as i32];
+        let dv = [d.x, d.y, d.z];
+        let av = [a.x, a.y, a.z];
+        let step: [i32; 3] = dv.map(|v| if v > 0.0 { 1 } else { -1 });
+        let mut t_max = [f64::INFINITY; 3];
+        let mut t_delta = [f64::INFINITY; 3];
+        for i in 0..3 {
+            if dv[i] != 0.0 {
+                let edge = f64::from(pos[i]) + if dv[i] > 0.0 { 1.0 } else { 0.0 };
+                t_max[i] = (edge - av[i]) / dv[i];
+                t_delta[i] = (1.0 / dv[i]).abs();
+            }
+        }
+        let mut last: Option<Sec> = None;
+        let mut face = [0i32; 3];
+        let mut t = 0.0f64;
+        let mut first = true;
+        for _ in 0..4096 {
+            self.stats.cells += 1;
+            match self.solid(&mut last, pos[0], pos[1], pos[2], now) {
+                None => {
+                    self.stats.unknown_sweeps += 1;
+                    return Sweep::Unknown { t };
+                }
+                Some(true) if !(first && skip_start) => {
+                    self.stats.hits += 1;
+                    return Sweep::Hit { t, point: a + d * t, normal: face, block: pos };
+                }
+                _ => {}
+            }
+            first = false;
+            let axis = if t_max[0] < t_max[1] {
+                if t_max[0] < t_max[2] { 0 } else { 2 }
+            } else if t_max[1] < t_max[2] {
+                1
+            } else {
+                2
+            };
+            t = t_max[axis];
+            if t > 1.0 {
+                return Sweep::Clear;
+            }
+            t_max[axis] += t_delta[axis];
+            pos[axis] += step[axis];
+            face = [0; 3];
+            face[axis] = -step[axis];
+        }
+        self.stats.unknown_sweeps += 1;
+        Sweep::Unknown { t }
+    }
+}
+
+/// Where the game's blocks come from in tests and the native runner: any
+/// world that can say what a block is.
+pub trait WorldSource {
+    /// Whether the block stops a projectile; `None` where there is no chunk.
+    fn solid(&self, x: i32, y: i32, z: i32) -> Option<bool>;
+}
+
+/// A [`WorldSource`] as the game would answer `render.query-sections` with it.
+pub fn section_of(source: &dyn WorldSource, s: Sec) -> Fill {
+    let mut bits = Box::new([0u8; 512]);
+    let (mut set, mut known) = (0u32, 0u32);
+    for i in 0..4096usize {
+        let (x, y, z) = (s.0 * 16 + (i & 15) as i32, s.1 * 16 + (i >> 8) as i32, s.2 * 16 + ((i >> 4) & 15) as i32);
+        match source.solid(x, y, z) {
+            Some(true) => {
+                bits[i >> 3] |= 1 << (i & 7);
+                set += 1;
+                known += 1;
+            }
+            Some(false) => known += 1,
+            None => {}
+        }
+    }
+    match (known, set) {
+        (0, _) => Fill::Unknown,
+        (_, 0) if known == 4096 => Fill::Empty,
+        (_, 4096) => Fill::Full,
+        _ => Fill::Mixed(bits),
+    }
+}
+
+impl WorldCache {
+    /// Answers the questions of the last tick from a synthetic world, as the game does one tick later.
+    pub fn serve(&mut self, source: &dyn WorldSource, wanted: Vec<Sec>, now: u64) {
+        let answers = wanted.into_iter().map(|sec| SectionAnswer { sec, fill: section_of(source, sec) }).collect();
+        self.answer(answers, now);
+    }
+}

docs/HD-RENDERER.md

@@ -20,6 +20,7 @@ Horizon действует правило clean-room. Исключение — P
 | Что | Где |
 |---|---|
 | Весь HD-конвейер: цели, проходы, WGSL-шейдеры (строками), тайлы света, AO, тени, bloom, tonemap, TAA | `horizon/crates/horizon-client/src/gfx/hd.rs` |
+| Объёмные облака (рэймарч слоя, тени облаков на землю) и объёмный туман (лучи света через тени каскадов), их цели и проходы; CPU-шум (2D, 3D Worley) | `horizon/crates/horizon-client/src/gfx/hd_volumes.rs`, `hd_noise.rs` |
 | Атмосфера: сборка текстуры неба (WGSL), чтение неба/дымки/тона света в шейдерах, цвет солнца (`sun_transmittance`) | `horizon/crates/horizon-client/src/gfx/hd_sky.rs` (+ `THIRD_PARTY_PHOTON.md`) |
 | Встраивание в кадр: G-буфер-проход, каскады теней, вызовы `hd.light` / `hd.finish`, джиттер, тайминги | `horizon/crates/horizon-client/src/gfx.rs` (`Renderer::render`, ищи `hd_on`, `AirDef fork:`) |
 | G-буфер террейна: `fs_gbuffer`, `fs_shadow` | `horizon/crates/horizon-client/src/terrain.wgsl` |
@@ -62,6 +63,7 @@ cd .. && rm -f horizon-patches/*.patch && git -C horizon format-patch -q $(cat H
    землёй решают потребители). Пайплайны `gbuffer_water` (секции) и `flat.water` (flat-путь).
 3a. **GTAO** (полразрешения, `Rg16Float`: окклюзия, дистанция) + depth-aware блюр 5×5. 3 среза × 5 шагов, радиус
    1.8 блока, шум IGN по кадру. Сила — `HdFrame.ambient.w` (`HORIZON_HD_AO=<число>`, 0 = выкл).
+3b. **Облака и туман** (`hd.volumes`, до освещения, после прохода неба): `hd cloud shadows` (карта 256² оптической толщины облаков по ходу солнца, ±1200 блоков вокруг камеры), `hd clouds` (половина разрешения мира, `Rgba16Float`: свет + пропускание; рэймарч слоя 192.33…264 блока, 8–26 шагов с джиттером IGN, свет — 3 шага с удвоением, небо — 1, 4 октавы многократного рассеяния Photon; история ping-pong с репроекцией по направлению и сдвигу камеры, вес до 0.9, отбрасывается при расхождении) и `hd fog` (половина разрешения: 18 шагов от камеры до глубины мира, не дальше 192 блоков, плотность — высотная дымка + утренний туман у земли + дождь + шум, свет — солнце × тень каскадов × фаза Photon + свет неба; вторая цель — длина луча для апсэмплинга). Ванильные облака при этом не рисуются (`hd_volumetric_clouds` в `gfx.rs`). `fs_light` накладывает облака на небо (`c·T + S`), туман на всё (`fog_at`: 4 текселя с весом по близости длины луча), а тень облаков (`cloud_shadow`) умножает прямой солнечный свет. `HORIZON_HD_CLOUDS=0` / `HORIZON_HD_VOLFOG=0` выключают (облака тогда ванильные, лучи — старые 14 шагов).
 4. **Освещение** `fs_light` → `lit` (HDR): пиксель неба (глубина мира 0, Оверворлд, без env-тумана) — это небо атмосферы + то, что мир нарисовал поверх ванильного неба (`max(scene − vanilla_sky(view), 0)`: спрайты луны, звёзды; квадрат ванильного солнца вырезается вокруг направления солнца и заменяется круглым диском с гало); облака (глубина > 0, нет в G-буфере, y > 8, дальше 48 блоков) на закате/рассвете окрашиваются цветом солнца. Свет неба: ванильный `lightmap` × подкраска цветом неба (зенит сверху, горизонт сбоку; яркость 1) × форма по нормали (вверх 1.1, вниз 0.66), только там, где есть небесный свет. Тени: ближний каскад — PCSS-lite (поиск блокировщиков 8 выборок, ширина полутени от расстояния до блокировщика, 12 выборок спирали Фогеля, повёрнутых IGN; сглаживает TAA), дальний — 3×3. Туман: цвет — небо над горизонтом в направлении пикселя (`haze_colour`) + воздушная перспектива `1 − exp(−d/700)` × 0.5. Далее прежнее: пиксель — вода, если `water_depth >= g` и перед водой в мировой глубине ничего нет
    (`d - wd <= 0.2%`); тогда освещается **дно** по данным G-буфера (одна выборка тени, без AO), а в альфу `lit` пишется 0.5 (признак воды). `max(небо·ambient.x, блоки·ambient.y)·AO + солнце·N·L·тень + точечные
    источники` × albedo + эмиссия; затем ванильный туман заново, объёмные лучи (14 шагов, Henyey-Greenstein g=0.6),
@@ -109,10 +111,12 @@ Bind groups кэшируются и пересоздаются только пр
 | 13 | AO |
 | 14 | глубина воды (`water_depth`) |
 | 15 | текстура неба (`sky_lut`) |
+| 16, 17 | объёмный туман (свет+пропускание) и длина его луча |
+| 18, 19 | объёмные облака, карта теней облаков |
 
 `HdFrame` (Rust и WGSL держать в синхроне!): `inverse_view_proj`, `resolution` (w, h, 1/w, 1/h), `params` (число
 источников, экспозиция, bloom, счётчик кадров), `cascades[2]`, `sun` (направление, сила), `sun_color` (rgb, ночь),
-`fog_color`, `fog`, `ambient` (тень неба, блоки, плотность воздуха, AO), `shadow` (вкл, R0, R1, тайлов в строке), `prev_view_proj`, `taa`, `taa_params`, `view_proj` (с джиттером, для лучей воды), `water` (x: эффект идёт, y: секунды волн mod 600, zw: камера x, z mod 256), `sky_color` (w: есть небо), `sky_sun` (xyz: на само солнце, w: 1 — небо рисует атмосфера), `sky_extra` (x: конец ванильного тумана неба, z: пасмурность от дождя 0..0.85), `sunrise` (ванильная полоса восхода/заката — вычитается из мира).
+`fog_color`, `fog`, `ambient` (тень неба, блоки, плотность воздуха, AO), `shadow` (вкл, R0, R1, тайлов в строке), `prev_view_proj`, `taa`, `taa_params`, `view_proj` (с джиттером, для лучей воды), `water` (x: эффект идёт, y: секунды волн mod 600, zw: камера x, z mod 256), `sky_color` (w: есть небо), `sky_sun` (xyz: на само солнце, w: 1 — небо рисует атмосфера), `sky_extra` (x: конец ванильного тумана неба, z: пасмурность от дождя 0..0.85), `sunrise` (ванильная полоса восхода/заката — вычитается из мира), `clouds` (низ слоя относительно камеры, толщина, вкл, секунды ветра), `cloud_cam` (x, z камеры по модулю 65536, добавка покрытия от дождя, история облаков годна), `cloud_dir` / `cloud_sun` (откуда и каким цветом светят облаку: солнце до чуть ниже горизонта, ночью луна), `vfog` (туман вкл, высота камеры, утренний туман).
 
 Композит воды (`WATER`, group 0): 0 `HdFrame`, 1 `lit`, 2 глубина G-буфера, 3 цвет воды, 4 нормаль воды, 5 глубина воды, 6–7 тени, 8 лайтмап, 9 сэмплер, 10 текстура неба. Проход неба (`SKY_PASS`, group 0): только `HdFrame`.
 
@@ -151,6 +155,11 @@ TAAU (2560×1440, GPU avg кадр, сцена Polygon): scale 1.0 — 18.1 мс
 текстурах и анимация воды), а при ошибке теней было 8.5%. Сравни с `HORIZON_HD_TAA=0` / `HORIZON_HD_AO=0` /
 `HORIZON_HD_SHADOW_FAST=0`, чтобы найти виновника.
 
+Графический полигон: `python3 tools/hd_bench.py` (`--list` — сцены; `--only polygon_noon` — одна сцена; `--env
+HORIZON_HD_TAA=0 --out run-home-bench/out/taa-off` — A/B; `--baseline run-home-bench/out/before` — diff ×6 и
+пороги; `--budget-ms 18` — GPU-бюджет). Сам копирует `Polygon`/`Hills` в `run-home-bench/home`, сокет
+`run-home-bench/c.sock`, одна игра за раз; отчёт `report.md` с таблицей, проходами GPU и кадрами.
+
 Отладка: временно выводи промежуточные величины цветом в `fs_light` (так нашли пустую карту теней и неверное
 направление солнца). Помни: солнце в мире идёт по оси X (`(-sin a, cos a, 0)`), а `Globals.sun` неба — в своей
 плоскости YZ.
@@ -172,7 +181,16 @@ TAAU (2560×1440, GPU avg кадр, сцена Polygon): scale 1.0 — 18.1 мс
 | Вода: проход `fs_water`, преломление, SSR, Френель, блик (`HORIZON_HD_WATER=0` — выкл) | готово | патч 19 (+20: без ванильной текстуры на поверхности, цвет темнее и глубже) |
 | Вода: светлее, густая мелкая рябь (26 волн), блик a=0.07 (мерцание на реке ≈1.4% пикселей >20/255) | готово | патч 21 |
 | Небо и атмосфера (Рэлей/Ми/озон, текстура неба, воздушная перспектива, цвет солнца из пропускания, голубоватый ambient по нормали, PCSS-lite ближнего каскада, диск солнца, цвет облаков на закате; порт констант и Chapman из Photon, MIT) | готово | патч 22 |
+| Закат как у Photon: атмосфера в Rec. 2020 (коэффициенты и матрицы Photon), фаза Клейна-Нишины, тинт и усиление солнца на закате/рассвете/синем часе (`get_sun_tint`), насыщенность неба у низкого солнца | готово | патч 23 |
+| Объёмные облака (рэймарч, мультирассеяние Photon, тени на землю, TAA-история, ванильные скрыты) | готово | патч 24 |
+| Объёмный туман (лучи через тени каскадов, высотная дымка, утренний туман, полразрешения) | готово | патч 25 |
 | API моделей по хэндлам (#30, уровень API 11: `model-id`, `model-generation`, `set-models-by-id`) | готово | патч 17 |
+| #41: пасмурность неба и сила солнца берутся из мирового уровня дождя (`Sky.rain`, ставит `apply_weather`), а не из наличия геометрии осадков | готово | в рабочем дереве форка |
+| #38: TAA без апскейла ищет историю по матрице прошлого кадра **с джиттером** (`HdScene.prev_view_proj_jittered`); `fs_taau` по-прежнему берёт матрицу без джиттера | готово | в рабочем дереве форка |
+| #35: ванильные облака (HD-облака выключены) красятся закатным цветом в собственном проходе (`hd::vanilla_cloud_tint` → цвет в `clouds::Input`), эвристика по глубине G-буфера убрана из `fs_light` | готово | в рабочем дереве форка |
+| #37: воздух (ванильный туман, aerial, объёмный туман, лучи, ореолы) на воде считается до **поверхности** и кладётся один раз поверх готовой воды: `fs_light` пишет во вторую цель `air` (рассеяние + пропускание), `fs_water` применяет её после поглощения | готово | в рабочем дереве форка |
+| #36: ванильная вода не рисует цвет в HD (`fs_translucent` при `Globals.hd_flags.x`, глубину оставляет); прозрачное перед водой (`d` ближе `wd`) не отключает HD-воду: вода считается на освещённом дне и добавляется к сцене с весом 0.7; преломление не берёт тексели с таким прозрачным (`textureGather` по альфе) | готово (проверены стекло; частицы и scale 0.67 не проверялись) | в рабочем дереве форка |
+| #39: веер восхода `vanilla_sunrise_weight` отсекается до цикла по 16 треугольникам выше горизонта (знак x стороны солнца и наклон ≤ α/3; проверено перебором 200 тыс. лучей без пропусков); `hd lighting` на рассвете 5.3 → 3.3 мс (M-серия, 2560×1440) | готово | в рабочем дереве форка |
 
 ## План (по порядку) и ТЗ
 
@@ -190,7 +208,7 @@ TAAU (2560×1440, GPU avg кадр, сцена Polygon): scale 1.0 — 18.1 мс
 3. **Небо и атмосфера** — СДЕЛАНО (патч 22, см. «Небо и свет» ниже). Исходное ТЗ: рассеяние Рэлея/Ми (предвычисленная LUT пропускания и небесного цвета в маленькой
    текстуре), солнце/луна дисками, звёзды из ванили; туман и лучи берут цвет из той же модели. Учесть дождь
    (`weather`), закат, Незер/Энд (там — ванильное небо).
-4. **Объёмные облака** (рэймарч слоя с шумом) + их тени на земле (в карту/маску солнца).
+4. **Объёмные облака** — СДЕЛАНО (патч 24, см. «Закат, облака и туман»). Осталось: перистые/высококучевые слои Photon, облака в отражении воды.
 5. **Блики и материалы**: specular солнца для металла техники (маска по оверлею/альбедо или атрибут модели из
    мода), мокрые поверхности и лужи в дождь.
 6. **PCSS** (мягкость тени по расстоянию до тенеотбрасывателя) и цветные тени через стекло/листву.
@@ -241,3 +259,19 @@ TAAU (2560×1440, GPU avg кадр, сцена Polygon): scale 1.0 — 18.1 мс
 (`light_of`: множитель (1, 0.93, 0.78)). Проверять баланс на `Polygon` в полдень (`time set 6000`) — белое должно
 оставаться белым с тёплым оттенком.
 
+
+## Закат, облака и туман (патчи 23–25): что знать преемнику
+
+- **Закат (23).** Небо марширует в Rec. 2020 (коэффициенты Photon сдвинуты матрицей `rec709_to_rec2020`, результат возвращается в 709): это убрало жёлто-зелёный горизонт. Добавлены фаза Клейна-Нишины для Ми и деполяризованная Рэлея, `sun_light_tint` (розоватый тинт и подъём яркости на закате, фиолетовый на синем часе, из `get_sun_tint`), сильнее насыщенность у низкого солнца (`sky_show`). Цвет прямого света (`light_of`) умножен на тот же тинт. Сверка: 12000/12500/13000 (запад) и 23000/23500 (восток) — оранжевый/розовый/пурпурный; полдень Polygon (6000) прежний.
+- **Облака (24).** Слой 192.33…264.33 блока (`CLOUD_BASE/CLOUD_THICKNESS`), ветер 3 блока/с (`CLOUD_WIND`), шум — текстуры, сгенерированные на CPU при создании HD (`hd_noise.rs`: 2D 256² покрытие/форма, 3D 64³ Worley). Плотность — по `clouds_cumulus_density` Photon (порог покрытия × форма, «яйцо» по высоте, эрозия Worley, резкий верх), рассеяние — `clouds_cumulus_scattering` (октавы, пудра, фазы). Цвет света — `cloud_light` (Rust): пропускание атмосферы на высоте солнца; солнце светит облакам до −0.2 по высоте, дальше луна. Воздушная перспектива `exp(−d/3600)` к цвету дымки. История сбрасывается при resize, телепорте и без TAA. Опция ванильных облаков «выкл» → `frame.clouds` пуст → нет ни облаков, ни теней. Тень: `cloud_shadow` в `fs_light` (карта оптической толщины; гаснет при солнце ниже ~0.1–0.25 по высоте).
+- **Туман (25).** `fs_fog`: 18 шагов, плотность `fog_sigma` (высотная дымка от y=62, масштаб 42; утренний туман — пока солнце на «утренней» стороне и низко; пятна из 3D-шума; дождь; затухание ниже y≈28–58, чтобы не светить в пещерах), свет — Photon-смесь двух HG, «вечернее свечение» ×1…3. Старые 14 шагов лучей остаются при `HORIZON_HD_VOLFOG=0`; ореолы вокруг источников мода — всегда.
+- **Тайминги.** Метки Metal (`HORIZON_SHADER_PACK_TIMING=1`, Hills, 2560×1440): `hd clouds` ≈ 6 мс (завышено: метка ловит ожидание соседних проходов), `hd cloud shadows` 0.2–3 (шум), `hd fog` ≈ 1.3. По среднему кадру GPU «оба выкл → оба вкл»: +0.2…3.7 мс (замеры шумные: рядом шла чужая игра на том же GPU). Как удешевить: у облаков — длина шага (14) и потолок шагов (26) в `fs_cloud`, 3 шага света, 4 октавы, облака в четверть разрешения; у тумана — `FOG_STEPS`.
+- **Разработка шейдеров.** `HORIZON_HD_SHADER_DIR=<папка>`: каждый HD-шейдер читается из `<папка>/<метка>.wgsl` (записывается из встроенного, если файла нет) — правки видны после перезапуска игры без пересборки; готовое переносится в константы вручную.
+- **Слабые места.** Облака не отражаются в воде (SSR берёт небо без облаков); не закрывают далёкую землю выше слоя (только небо); карта теней облаков ±1200 блоков и почти не работает при солнце ниже ~10°; туман не знает рельефа (только высоту над y=62); нет перистых облаков; на быстром повороте камеры история облаков отбрасывается (кратковременный шум).
+
+## Заметки по исправлениям #35–#41 (преемнику)
+
+- **Цели света.** `fs_light` пишет две цели: `lit` и `air` (`Rgba16Float`). Альфа `lit`: 1 — обычный пиксель, 0.5 — вода (в `lit` дно без воздуха, в `air` рассеяние воздуха до поверхности и пропускание в альфе), 0.6 — прозрачное перед водой (в `lit` сцена как нарисована, в `air.rgb` освещённое дно). Привязка 11 композита воды — `air`.
+- **Ванильная вода в HD.** Пока `hd.water_active()`, `fs_translucent` не рисует цвет воды (альфа 0), но пишет её глубину; флаг — `Globals.hd_flags.x` (поле добавлено в Rust-`Globals`, `terrain.wgsl`, `entity.wgsl`; пишется после `hd.write` и в `hd.main_globals`). Вода без дна (`g = 0`) считается водой толщиной 48.
+- **Не сделано.** Полупрозрачное перед водой берёт вес 0.7 на «вклад воды» (приближение: настоящий порядок «вода → прозрачное» потребовал бы разделить проход сцены). Частицы перед водой, `HORIZON_HD_SCALE=0.67`, поиск мерцания на рябь после этих правок не прогонялись.
+- **`HORIZON_HD_TAA=0`.** На Polygon в полдень (`tp @s 40 76 40 135 15`) HD с выключенным TAA выглядит так же (дымка, небо, тени на месте), GPU 16.5 мс против 18.1 мс с TAA (минус ≈ проход TAA); потери вида и падения до 4.8 мс не воспроизвелись. В коде `HORIZON_HD_TAA` читают только `taa_enabled()` (джиттер, проход `taa`, история), остальные проходы от него не зависят. Если проявится снова — проверь, что до шота прошёл `/airdef shader hd` (при неготовой команде кадр без HD ~5 мс).

horizon-patches/0001-Mod-API-AirDef-fork-world-models-client-particles-so.patch

@@ -1,7 +1,7 @@
 From 3de7a6875140a107e28563cc44489b55f5794517 Mon Sep 17 00:00:00 2001
 From: chexit <chexit@duck.com>
 Date: Wed, 28 Oct 2026 12:37:45 +0300
-Subject: [PATCH 01/22] Mod API (AirDef fork): world models, client particles,
+Subject: [PATCH 01/25] Mod API (AirDef fork): world models, client particles,
  sounds, ground heights
 
 render.set-models draws block models with an interpolated pose per id;

horizon-patches/0002-cargo-horizon-mod-report-particles-and-sounds.patch

@@ -1,7 +1,7 @@
 From a6d64e6415bf618539af464e521091e72b72d72f Mon Sep 17 00:00:00 2001
 From: chexit <chexit@duck.com>
 Date: Wed, 28 Oct 2026 12:39:45 +0300
-Subject: [PATCH 02/22] cargo-horizon-mod: report particles and sounds
+Subject: [PATCH 02/25] cargo-horizon-mod: report particles and sounds
 
 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
 ---

horizon-patches/0003-Mod-API-AirDef-fork-full-screen-post-pass-for-mods.patch

@@ -1,7 +1,7 @@
 From ee79b3562feebe51959a01f1585a9e85bd53ccb5 Mon Sep 17 00:00:00 2001
 From: chexit <chexit@duck.com>
 Date: Wed, 28 Oct 2026 13:33:10 +0300
-Subject: [PATCH 03/22] Mod API (AirDef fork): full-screen post pass for mods
+Subject: [PATCH 03/25] Mod API (AirDef fork): full-screen post pass for mods
 
 render.set-post compiles a mod's WGSL after a prelude (camera matrices,
 time, 256 vec4 of params, the world's colour and depth) and runs it after

horizon-patches/0004-Mod-models-draw-far-models-as-scaled-impostors-past-.patch

@@ -1,7 +1,7 @@
 From 2b137dbbedd540daeebc7f5e387847aeb56a1355 Mon Sep 17 00:00:00 2001
 From: chexit <chexit@duck.com>
 Date: Wed, 28 Oct 2026 22:09:30 +0300
-Subject: [PATCH 04/22] Mod models: draw far models as scaled impostors past
+Subject: [PATCH 04/25] Mod models: draw far models as scaled impostors past
  the far plane, cull at 4096
 
 ---

horizon-patches/0005-Mod-cameras-render.set-views-draws-the-world-from-ot.patch

@@ -1,7 +1,7 @@
 From c8ebca6e0af68630e65211844b34d25c5b985c03 Mon Sep 17 00:00:00 2001
 From: chexit <chexit@duck.com>
 Date: Wed, 28 Oct 2026 22:31:00 +0300
-Subject: [PATCH 05/22] Mod cameras: render.set-views draws the world from
+Subject: [PATCH 05/25] Mod cameras: render.set-views draws the world from
  other points into pictures that HUD view shapes show (API level 9)
 
 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

horizon-patches/0006-Mods-more-fuel-per-tick-and-per-event-AirDef-plans-r.patch

@@ -1,7 +1,7 @@
 From 8d2261fc4f8072c32e454139cfea7a8c0cd9d664 Mon Sep 17 00:00:00 2001
 From: chexit <chexit@duck.com>
 Date: Wed, 28 Oct 2026 23:08:21 +0300
-Subject: [PATCH 06/22] Mods: more fuel per tick and per event (AirDef plans
+Subject: [PATCH 06/25] Mods: more fuel per tick and per event (AirDef plans
  raids)
 
 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

horizon-patches/0007-Mod-cameras-up-to-1920x1080-full-screen-replays.patch

@@ -1,7 +1,7 @@
 From 6c548de34def8e4a624d734243418090798bd16a Mon Sep 17 00:00:00 2001
 From: chexit <chexit@duck.com>
 Date: Wed, 28 Oct 2026 23:25:29 +0300
-Subject: [PATCH 07/22] Mod cameras up to 1920x1080 (full-screen replays)
+Subject: [PATCH 07/25] Mod cameras up to 1920x1080 (full-screen replays)
 
 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
 ---

horizon-patches/0008-Mod-cameras-distant-terrain-tiles-fog-measured-from-.patch

@@ -1,7 +1,7 @@
 From 9b9e93269d67401cc620567a884d5ce97f68d76e Mon Sep 17 00:00:00 2001
 From: chexit <chexit@duck.com>
 Date: Thu, 29 Oct 2026 11:15:11 +0300
-Subject: [PATCH 08/22] Mod cameras: distant terrain tiles, fog measured from
+Subject: [PATCH 08/25] Mod cameras: distant terrain tiles, fog measured from
  the camera, no impostors while one is shown
 
 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

horizon-patches/0009-Mods-game.world-id-so-mods-keep-state-per-world-API-.patch

@@ -1,7 +1,7 @@
 From 065d9fa02966238a5bd9ff460392a1a809db0b11 Mon Sep 17 00:00:00 2001
 From: chexit <chexit@duck.com>
 Date: Thu, 29 Oct 2026 11:25:45 +0300
-Subject: [PATCH 09/22] Mods: game.world-id, so mods keep state per world (API
+Subject: [PATCH 09/25] Mods: game.world-id, so mods keep state per world (API
  level 9)
 
 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

horizon-patches/0010-cargo-horizon-mod-trial-runs-behind-feature-full-so-.patch

@@ -1,7 +1,7 @@
 From 1bf28135fd9a31f837323dc3a8d81ed73343d816 Mon Sep 17 00:00:00 2001
 From: chexit <chexit@duck.com>
 Date: Thu, 29 Oct 2026 12:01:08 +0300
-Subject: [PATCH 10/22] cargo-horizon-mod: trial runs behind feature full, so a
+Subject: [PATCH 10/25] cargo-horizon-mod: trial runs behind feature full, so a
  packing-only tool skips wasmtime
 
 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

horizon-patches/0011-HD-lighting-G-buffer-pass-per-pixel-mod-point-lights.patch

@@ -1,7 +1,7 @@
 From 0a56f5616df4699588cbcc529d4720661baa810f Mon Sep 17 00:00:00 2001
 From: chexit <chexit@duck.com>
 Date: Thu, 29 Oct 2026 13:18:43 +0300
-Subject: [PATCH 11/22] HD lighting: G-buffer pass, per-pixel mod point lights
+Subject: [PATCH 11/25] HD lighting: G-buffer pass, per-pixel mod point lights
  in HDR, bloom and tone curve; render.set-lights and render.set-lighting (API
  level 10)
 

horizon-patches/0012-HD-lighting-stage-2-sun-and-moon-shadow-cascades-the.patch

@@ -1,7 +1,7 @@
 From 9ebf0031fe9ba6b7f02afb26e4fd3a1ba4ddb0d0 Mon Sep 17 00:00:00 2001
 From: chexit <chexit@duck.com>
 Date: Thu, 29 Oct 2026 13:59:43 +0300
-Subject: [PATCH 12/22] HD lighting stage 2: sun and moon shadow cascades, the
+Subject: [PATCH 12/25] HD lighting stage 2: sun and moon shadow cascades, the
  world relit (sun by face angle and shadow, sky and block light through the
  lightmap), light shafts and halos, fog over it again, a light colour grade
 

horizon-patches/0013-HD-bind-groups-cached-until-a-resize-or-a-new-source.patch

@@ -1,7 +1,7 @@
 From 7a5a38f68923aec62f10bfa0df50b436474ed612 Mon Sep 17 00:00:00 2001
 From: chexit <chexit@duck.com>
 Date: Thu, 29 Oct 2026 16:19:53 +0300
-Subject: [PATCH 13/22] HD: bind groups cached until a resize or a new source,
+Subject: [PATCH 13/25] HD: bind groups cached until a resize or a new source,
  shadow passes draw only the entities that cast shadows
 
 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

horizon-patches/0014-HD-lights-culled-per-16x16-tile-surface-and-halo-lis.patch

@@ -1,7 +1,7 @@
 From 8020811e57d4b5a9ea1cd72d30ce859dc5095d35 Mon Sep 17 00:00:00 2001
 From: chexit <chexit@duck.com>
 Date: Thu, 29 Oct 2026 16:25:44 +0300
-Subject: [PATCH 14/22] HD: lights culled per 16x16 tile (surface and halo
+Subject: [PATCH 14/25] HD: lights culled per 16x16 tile (surface and halo
  lists built on the CPU), a naga test for the lighting shaders
 
 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

horizon-patches/0015-HD-GPU-time-per-pass-in-the-F3-timing-list-half-reso.patch

@@ -1,7 +1,7 @@
 From 72d3fddfea329e578162656151350f0aa2efd323 Mon Sep 17 00:00:00 2001
 From: chexit <chexit@duck.com>
 Date: Thu, 29 Oct 2026 16:43:36 +0300
-Subject: [PATCH 15/22] HD: GPU time per pass in the F3 timing list,
+Subject: [PATCH 15/25] HD: GPU time per pass in the F3 timing list,
  half-resolution GTAO with a depth-aware blur
 
 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

horizon-patches/0016-HD-shadows-draw-only-sun-facing-quads-and-skip-burie.patch

@@ -1,7 +1,7 @@
 From 1fd83a821bf270879d8ece5aa583f200ed920d89 Mon Sep 17 00:00:00 2001
 From: chexit <chexit@duck.com>
 Date: Thu, 29 Oct 2026 17:02:02 +0300
-Subject: [PATCH 16/22] HD: shadows draw only sun-facing quads and skip buried
+Subject: [PATCH 16/25] HD: shadows draw only sun-facing quads and skip buried
  sections, the far cascade every second frame; TAA (Halton jitter,
  reprojection by depth, YCoCg variance clipping) before bloom
 

horizon-patches/0017-Mods-model-handles-render.model-id-model-generation-.patch

@@ -1,7 +1,7 @@
 From 1502d359d599228fe0f44ce6b99a3fded2ac5ea0 Mon Sep 17 00:00:00 2001
 From: chexit <chexit@duck.com>
 Date: Thu, 29 Oct 2026 17:02:02 +0300
-Subject: [PATCH 17/22] Mods: model handles (render.model-id, model-generation,
+Subject: [PATCH 17/25] Mods: model handles (render.model-id, model-generation,
  set-models-by-id; API level 11) so mods send no model names each tick;
  clear-post and set-lighting documented
 

horizon-patches/0018-HD-temporal-upscaling-HORIZON_HD_SCALE-world-G-buffe.patch

@@ -1,7 +1,7 @@
 From 0f9d99b8ad3e4b72e621d84c2396cf1d3d2b7a33 Mon Sep 17 00:00:00 2001
 From: chexit <chexit@duck.com>
 Date: Thu, 29 Oct 2026 17:19:57 +0300
-Subject: [PATCH 18/22] HD: temporal upscaling (HORIZON_HD_SCALE: world,
+Subject: [PATCH 18/25] HD: temporal upscaling (HORIZON_HD_SCALE: world,
  G-buffer and lighting at a lower size, rebuilt to the window in the TAA
  pass); fix flickering shadows near the player (the near cascade lost its
  sections on frames the far one was held, the held far matrix ignored the

horizon-patches/0019-HD-water-its-own-pass-colour-normal-depth-the-floor-.patch

@@ -1,7 +1,7 @@
 From 38250c4392e27d5700842ca6ee47291dd1831b72 Mon Sep 17 00:00:00 2001
 From: chexit <chexit@duck.com>
 Date: Thu, 29 Oct 2026 17:47:52 +0300
-Subject: [PATCH 19/22] HD water: its own pass (colour, normal, depth), the
+Subject: [PATCH 19/25] HD water: its own pass (colour, normal, depth), the
  floor under it lit, a composite with world-space waves, refraction with depth
  absorption in the biome colour, screen-space reflections, Fresnel and a
  shadowed sun glint (HORIZON_HD_WATER=0 to switch off)

horizon-patches/0020-HD-water-no-vanilla-texture-on-the-surface-the-biome.patch

@@ -1,7 +1,7 @@
 From dbc6f8a6e9c2eeabe1de15f1794013c90be7faa5 Mon Sep 17 00:00:00 2001
 From: chexit <chexit@duck.com>
 Date: Thu, 29 Oct 2026 17:56:04 +0300
-Subject: [PATCH 20/22] HD water: no vanilla texture on the surface (the biome
+Subject: [PATCH 20/25] HD water: no vanilla texture on the surface (the biome
  colour only), a darker, deeper colour
 
 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

horizon-patches/0021-HD-sky-and-light-a-physical-atmosphere-Rayleigh-Mie-.patch

@@ -1,7 +1,7 @@
 From 13e74537dd6e63482e3613e0e416de1158944dfe Mon Sep 17 00:00:00 2001
 From: chexit <chexit@duck.com>
 Date: Thu, 29 Oct 2026 18:38:19 +0300
-Subject: [PATCH 21/22] HD sky and light: a physical atmosphere (Rayleigh, Mie,
+Subject: [PATCH 21/25] HD sky and light: a physical atmosphere (Rayleigh, Mie,
  ozone; constants and transmittance after Photon, MIT) for the sky, haze, fog
  and water reflections; warmer sunlight from the atmosphere's transmittance, a
  gentle sky-coloured ambient, soft PCSS-lite shadows near the player, a haze

horizon-patches/0022-HD-water-a-darker-blue-a-little-clearer-ripples-a-li.patch

@@ -1,7 +1,7 @@
 From 6277e051a89c2537570982f6ef275887193c05cf Mon Sep 17 00:00:00 2001
 From: chexit <chexit@duck.com>
 Date: Thu, 29 Oct 2026 19:02:16 +0300
-Subject: [PATCH 22/22] HD water: a darker blue, a little clearer, ripples a
+Subject: [PATCH 22/25] HD water: a darker blue, a little clearer, ripples a
  little higher
 
 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

horizon-patches/0025-HD-fixes-rain-level-from-the-world-not-from-rain-geo.patch

@@ -0,0 +1,992 @@
+From fdec4960983bdff82f3793460f9a5234f0cd3f49 Mon Sep 17 00:00:00 2001
+From: chexit <chexit@duck.com>
+Date: Thu, 29 Oct 2026 22:56:15 +0300
+Subject: [PATCH 25/25] HD fixes: rain level from the world not from rain
+ geometry (#41), TAA history on the jittered grid (#38), vanilla cloud tint
+ without a depth heuristic (#35), air fog once over water (#37), translucent
+ things in front of HD water (#36), cheaper sunrise fan (#39), halos in thick
+ air capped; mods: render.set-time-override (API level 13) so replays show
+ their recorded time of day (#57)
+
+Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
+---
+ crates/horizon-client/src/entity.wgsl    |   2 +
+ crates/horizon-client/src/environment.rs |   5 +
+ crates/horizon-client/src/game.rs        |  18 +-
+ crates/horizon-client/src/gfx.rs         |  52 ++-
+ crates/horizon-client/src/gfx/hd.rs      | 411 ++++++++++++++++-------
+ crates/horizon-client/src/gfx/hd_sky.rs  |   8 +
+ crates/horizon-client/src/terrain.wgsl   |   8 +
+ crates/horizon-mod-sdk/wit/horizon.wit   |   5 +
+ crates/horizon-mods/src/api_level.rs     |   6 +-
+ crates/horizon-mods/src/runtime.rs       |  12 +
+ docs/api/mods-reference.md               |   1 +
+ 11 files changed, 387 insertions(+), 141 deletions(-)
+
+diff --git a/crates/horizon-client/src/entity.wgsl b/crates/horizon-client/src/entity.wgsl
+index 61bc1f92a..b3fc9bc82 100644
+--- a/crates/horizon-client/src/entity.wgsl
++++ b/crates/horizon-client/src/entity.wgsl
+@@ -20,6 +20,8 @@ struct Globals {
+     crumbling_sprite: vec4<f32>,
+     // Selection outline parameters (read by terrain.wgsl).
+     outline_params: vec4<f32>,
++    // AirDef fork. x: the HD water draws the water (fs_translucent leaves vanilla's out).
++    hd_flags: vec4<f32>,
+     // Horizon Extras' dynamic lights: camera-relative position and level (dynamic_light.rs).
+     dynamic_lights: array<vec4<f32>, 16>,
+ }
+diff --git a/crates/horizon-client/src/environment.rs b/crates/horizon-client/src/environment.rs
+index 20855b749..9b8acf13f 100644
+--- a/crates/horizon-client/src/environment.rs
++++ b/crates/horizon-client/src/environment.rs
+@@ -141,6 +141,9 @@ pub struct Sky {
+     pub fog_end: f32,
+     /// `visual/cloud_fog_end_distance`.
+     pub cloud_fog_end: f32,
++    /// AirDef fork: the world's rain level (0..1), set by `apply_weather`. The HD sky reads this
++    /// rather than the presence of rain geometry near the camera.
++    pub rain: f32,
+ }
+ impl Environment {
+     pub fn load(root: &Path) -> Result<Self> {
+@@ -305,6 +308,7 @@ impl Environment {
+                 .base
+                 .get("minecraft:visual/fog_end_distance")
+                 .map_or(1024.0, |v| v[0]),
++            rain: 0.0,
+             cloud_fog_end: self
+                 .base
+                 .get("minecraft:visual/cloud_fog_end_distance")
+@@ -315,6 +319,7 @@ impl Environment {
+ /// WeatherAttributes: rain then thunder layers lerped by their levels
+ /// (rain counts only the part not covered by thunder).
+ pub fn apply_weather(sky: &mut Sky, rain: f32, thunder: f32) {
++    sky.rain = rain.clamp(0.0, 1.0);
+     let grey = |c: [f32; 3]| c[0] * 0.3 + c[1] * 0.59 + c[2] * 0.11;
+     let lerp3 = |t: f32, a: [f32; 3], b: [f32; 3]| -> [f32; 3] {
+         std::array::from_fn(|i| a[i] + (b[i] - a[i]) * t)
+diff --git a/crates/horizon-client/src/game.rs b/crates/horizon-client/src/game.rs
+index 366be39c4..fad8de187 100644
+--- a/crates/horizon-client/src/game.rs
++++ b/crates/horizon-client/src/game.rs
+@@ -8370,6 +8370,14 @@ impl Game<'_> {
+             .collect()
+     }
+ 
++    /// The time of day the player sees: a mod's override (a replay's recorded time), else the world's.
++    fn shown_day_time(&self) -> i64 {
++        self.mods
++            .mods
++            .time_override()
++            .map_or(self.world.day_time, |t| t as i64)
++    }
++
+     fn sky_darken(&self) -> i32 {
+         if self.dim == Dim::Nether {
+             return 11;
+@@ -8378,12 +8386,12 @@ impl Game<'_> {
+             let sky = self
+                 .res
+                 .end_environment()
+-                .sample(self.world.day_time, None, None);
++                .sample(self.shown_day_time(), None, None);
+             return (15.0 - 15.0 * sky.sky_light_level).round() as i32;
+         }
+         let (rain, thunder) = self.world.weather.levels(1.0);
+         // Sampled once per (time, weather): every mob asks each tick.
+-        let key = (self.world.day_time, rain.to_bits(), thunder.to_bits());
++        let key = (self.shown_day_time(), rain.to_bits(), thunder.to_bits());
+         if let Some((k, darken)) = self.sky_darken_memo.get()
+             && k == key
+         {
+@@ -8392,7 +8400,7 @@ impl Game<'_> {
+         let mut sky = self
+             .res
+             .environment()
+-            .sample(self.world.day_time, None, None);
++            .sample(self.shown_day_time(), None, None);
+         horizon_client::environment::apply_weather(&mut sky, rain, thunder);
+         // Level.updateSkyBrightness: darkening from the sky light level.
+         let darken = (15.0 - 15.0 * sky.sky_light_level).round() as i32;
+@@ -8898,7 +8906,7 @@ impl Game<'_> {
+             "first_quarter",
+             "waxing_gibbous",
+         ];
+-        let phase = phases[(self.world.day_time / 24000).rem_euclid(8) as usize];
++        let phase = phases[(self.shown_day_time() / 24000).rem_euclid(8) as usize];
+         body(
+             &format!("environment/celestial/moon/{phase}"),
+             sky.moon_angle,
+@@ -11608,7 +11616,7 @@ impl Game<'_> {
+         );
+         // visual/water_fog_color: no dimension sets it, its default is #050533.
+         let water_fog = blend(|b| Some(b.water_fog), [0.0; 3]);
+-        let mut sky = environment.sample(self.world.day_time, Some(biome_sky), Some(biome_fog));
++        let mut sky = environment.sample(self.shown_day_time(), Some(biome_sky), Some(biome_fog));
+         let (rain, thunder) = if self.dim == Dim::Overworld {
+             self.world.weather.levels(alpha as f32)
+         } else {
+diff --git a/crates/horizon-client/src/gfx.rs b/crates/horizon-client/src/gfx.rs
+index 072090e33..a8031c1f6 100644
+--- a/crates/horizon-client/src/gfx.rs
++++ b/crates/horizon-client/src/gfx.rs
+@@ -194,6 +194,9 @@ struct Globals {
+     crumbling_sprite: [f32; 4],
+     /// Framebuffer size, selection stroke width, perspective layering scale.
+     outline_params: [f32; 4],
++    /// AirDef fork. x: 1 while the HD water draws the water (fs_translucent then leaves vanilla's
++    /// water out of the colour and keeps its depth).
++    hd_flags: [f32; 4],
+     /// Horizon Extras' dynamic lights: camera-relative position and level (`dynamic_light`).
+     dynamic_lights: [[f32; 4]; crate::dynamic_light::MAX],
+ }
+@@ -578,7 +581,7 @@ pub struct Renderer {
+     hd_far: Option<(Mat4, glam::DVec3, Vec3, u32)>,
+     /// HD's TAA: frames jittered so far, and the last one's unjittered view-projection and camera.
+     taa_frame: u32,
+-    taa_prev: Option<(Mat4, glam::DVec3)>,
++    taa_prev: Option<(Mat4, glam::DVec3, Mat4)>,
+     hd: Option<hd::Hd>,
+     mod_params: (Vec<f32>, f32),
+     /// Time the shader pack's passes on the GPU (F3, or `HORIZON_SHADER_PACK_TIMING`).
+@@ -1207,17 +1210,15 @@ impl Renderer {
+         if sprite_arrays > 1 {
+             log::info!("Horizon: {layers} block textures in {sprite_arrays} arrays");
+         }
++        // AirDef fork, HD water: the sprite layers terrain.wgsl's fs_water takes for water (and
++        // fs_translucent clears while the HD water draws it instead).
+         let sprite_constants = [
+             ("SPRITE_ARRAYS", f64::from(sprite_arrays)),
+             ("SPRITE_SPLIT", f64::from(split)),
+-        ];
+-        // AirDef fork, HD water: the sprite layers terrain.wgsl's fs_water takes for water.
+-        let water_constants = [
+-            ("SPRITE_ARRAYS", f64::from(sprite_arrays)),
+-            ("SPRITE_SPLIT", f64::from(split)),
+             ("WATER_STILL", f64::from(water_layers[0])),
+             ("WATER_FLOW", f64::from(water_layers[1])),
+         ];
++        let water_constants = sprite_constants;
+         let bindings = device.create_bind_group_layout(&wgpu::BindGroupLayoutDescriptor {
+             label: Some("Horizon terrain bindings"),
+             entries: &[
+@@ -2823,7 +2824,7 @@ impl Renderer {
+             mip_levels,
+             mipmaps: mip_levels - 1,
+             terrain_layout: bindings,
+-            terrain_sprites: sprite_constants.map(|(_, v)| v),
++            terrain_sprites: [f64::from(sprite_arrays), f64::from(split)],
+             sprite_sampler,
+             lightmap_view,
+             lightmap_sampler,
+@@ -4049,7 +4050,7 @@ impl Renderer {
+         };
+         let taa_prev = std::mem::replace(
+             &mut self.taa_prev,
+-            taa.then_some((unjittered, frame.camera)),
++            taa.then_some((unjittered, frame.camera, view_proj)),
+         );
+         if frame.title {
+             self.panorama.prepare(
+@@ -4135,6 +4136,7 @@ impl Renderer {
+                 frame.glint_ticks,
+             ],
+             outline_params: outline_params(self.config.width, self.config.height),
++            hd_flags: [0.0; 4],
+             dynamic_lights: {
+                 let mut lights = [[0.0; 4]; crate::dynamic_light::MAX];
+                 for (to, from) in lights.iter_mut().zip(frame.dynamic_lights) {
+@@ -4260,11 +4262,14 @@ impl Renderer {
+             taa: taa && taa_prev.is_some(),
+             jitter_px,
+             prev_view_proj: taa_prev.map_or(unjittered, |p| p.0),
++            prev_view_proj_jittered: taa_prev.map_or(view_proj, |p| p.2),
+             camera_delta: taa_prev.map_or(Vec3::ZERO, |p| (frame.camera - p.1).as_vec3()),
+             // The world's sun: vanilla turns the sky -90° about Y, so it crosses from east to west.
+             sun: Vec3::new(-sun_angle.sin(), sun_angle.cos(), 0.0),
+             dark: 1.0 - frame.sky.sky_light_factor,
+-            rain: if frame.weather.is_empty() { 0.0 } else { 0.7 },
++            // The world's rain level (fades in and out with the weather), not the rain geometry
++            // near the camera: hiding the particles or standing under a roof leaves the sky alone.
++            rain: frame.sky.rain.clamp(0.0, 1.0) * 0.7,
+             fog_color,
+             fog,
+             sky: frame.skybox && !frame.end_sky && !frame.nether_lighting && !frame.underwater,
+@@ -4827,7 +4832,20 @@ impl Renderer {
+             + shadow_quads
+             + translucent_particle_quads
+             + translucent_item_quads;
+-        let cloud_quads = if let Some(input) = &frame.clouds {
++        // AirDef fork: vanilla's clouds (HD's volumetric ones off) take the low sun's colour in their
++        // own colour, so a mountain or glass behind them does not change it.
++        let cloud_input = frame.clouds.as_ref().map(|c| {
++            if !hd_wanted || !hd_scene.sky || hd::clouds_enabled() {
++                return crate::clouds::Input { ..*c };
++            }
++            let [r, g, b, a] = c.color;
++            let [tr, tg, tb] = hd::vanilla_cloud_tint(&hd_scene);
++            crate::clouds::Input {
++                color: [r * tr, g * tg, b * tb, a],
++                ..*c
++            }
++        });
++        let cloud_quads = if let Some(input) = &cloud_input {
+             let (rebuilt, uniform) =
+                 crate::spans::time("clouds", || self.cloud_mesh.prepare(input));
+             let vertices = self.cloud_mesh.vertices.len() as u64;
+@@ -5154,6 +5172,15 @@ impl Renderer {
+             if let Some(settings) = frame.hd {
+                 hd.write(&self.queue, &hd_scene, frame.hd_lights, settings);
+             }
++            // vanilla's translucent water leaves the colour while the HD water draws it.
++            let hd_flags_at = std::mem::offset_of!(Globals, hd_flags) as u64;
++            let hd_flags: [f32; 4] = [if hd.water_active() { 1.0 } else { 0.0 }, 0.0, 0.0, 0.0];
++            self.uploads.buffer(
++                &mut encoder,
++                &self.globals,
++                hd_flags_at,
++                bytemuck::bytes_of(&hd_flags),
++            );
+             hd.set_timing(device, &self.queue, self.pass_timing);
+             hd.timing_begin(device, &self.queue);
+             // The sun's (or moon's) shadow cascades: the world's globals swapped for the light's.
+@@ -5184,6 +5211,11 @@ impl Renderer {
+                 }
+                 self.queue
+                     .write_buffer(&hd.main_globals, 0, bytemuck::bytes_of(&globals));
++                self.queue.write_buffer(
++                    &hd.main_globals,
++                    hd_flags_at,
++                    bytemuck::bytes_of(&hd_flags),
++                );
+                 // Facing the light only: the nearest surface to it is always one that does.
+                 let toward = (hd_shadow_fast() && self.sides_on).then(|| shadow_dir * 1.0e5);
+                 for (c, cascade) in hd_cascades.iter().enumerate() {
+diff --git a/crates/horizon-client/src/gfx/hd.rs b/crates/horizon-client/src/gfx/hd.rs
+index 3b9daabf4..e84a618a9 100644
+--- a/crates/horizon-client/src/gfx/hd.rs
++++ b/crates/horizon-client/src/gfx/hd.rs
+@@ -133,6 +133,10 @@ pub struct HdScene {
+     pub view_proj: Mat4,
+     /// Last frame's view-projection without jitter, and the camera's move since (TAA).
+     pub prev_view_proj: Mat4,
++    /// The same frame's matrix as it was drawn, jitter included. History kept on the jittered
++    /// pixel grid (`fs_taa`, scale 1) is looked up with this; `fs_taau` resolves the history on the
++    /// unjittered output grid and uses `prev_view_proj`.
++    pub prev_view_proj_jittered: Mat4,
+     pub camera_delta: glam::Vec3,
+     /// This frame is anti-aliased over time (the projection is jittered).
+     pub taa: bool,
+@@ -403,31 +407,104 @@ fn fog_at(px: vec2<i32>, dist: f32) -> vec4<f32> {
+     return sum / total;
+ }
+ 
++struct LightOut {
++    // The lit colour; alpha 0.5 marks water (the floor under it, lit without any air), 0.6 an
++    // object in front of the water (the scene as drawn).
++    @location(0) lit: vec4<f32>,
++    // Water: the air between the camera and the surface (scattered light, transmittance);
++    // in front of the water: the floor lit (rgb); else nothing.
++    @location(1) air: vec4<f32>,
++}
++
++// An opaque surface lit: the ambient, the sun and the mods' lights over its albedo.
++fn shade_surface(px: vec2<i32>, p: vec3<f32>, water: bool) -> vec3<f32> {
++    let sun = frame.sun.xyz;
++    let sun_on = frame.sun.w;
++    let atmosphere = frame.sky_sun.w > 0.5;
++    let count = u32(frame.params.x);
++    let tile = ((u32(px.y) >> 4u) * u32(frame.shadow.w) + (u32(px.x) >> 4u)) * 4u;
++    let surface_start = tiles[tile];
++    let surface_all = tiles[tile + 1u] == 0xffffffffu;
++    let surface_count = select(tiles[tile + 1u], count, surface_all);
++    let n = normalize(textureLoad(normal_tex, px, 0).xyz);
++    let albedo = textureLoad(albedo_tex, px, 0);
++    let lm = textureLoad(light_tex, px, 0).xy;
++    // Vanilla's light (sky and blocks through the lightmap), shaded where the sun can't reach.
++    let base = textureSampleLevel(lightmap, linear, clamp(vec2<f32>(lm.y, lm.x) * (15.0 / 16.0) + 0.5 / 16.0, vec2<f32>(0.5 / 16.0), vec2<f32>(15.5 / 16.0)), 0.0).rgb;
++    let block = textureSampleLevel(lightmap, linear, vec2<f32>(lm.y * (15.0 / 16.0) + 0.5 / 16.0, 0.5 / 16.0), 0.0).rgb;
++    let sky_reach = smoothstep(0.35, 0.95, lm.x);
++    var s = 1.0;
++    let ndl = dot(n, sun);
++    if sun_on > 0.0 && ndl > 0.0 && sky_reach > 0.0 { s = shadow_taps(p, n, select(1, 0, water)) * cloud_shadow(p); } else { s = 0.0; }
++    // Shadowed sky light (ambient) keeps vanilla's look, blocks' light stays as is; the sun adds
++    // direct light by the face's angle.
++    let direct = frame.sun_color.rgb * sun_on * max(ndl, 0.0) * s * sky_reach;
++    // Contact shadows from the ambient occlusion: on the ambient and blocks' light fully, on
++    // the mods' lights by half, not on the sun or on emission.
++    var occlusion = 1.0;
++    // (The water dims and blurs the floor under it: no occlusion there.)
++    if frame.ambient.w > 0.0 && !water { occlusion = ao_at(px, length(p)); }
++    let ao_ambient = mix(1.0, occlusion, frame.ambient.w);
++    let ao_lights = mix(1.0, occlusion, frame.ambient.w * 0.5);
++    // The sky's light is bluish from above and carries the horizon's colour from the sides;
++    // faces turned up take more of it than the ones turned down.
++    var sky_tint = vec3<f32>(1.0);
++    if atmosphere {
++        let reach = smoothstep(0.25, 0.9, lm.x);
++        let up = clamp(n.y * 0.5 + 0.5, 0.0, 1.0);
++        let shape = mix(0.66, 1.1, smoothstep(0.1, 1.0, up));
++        let hue = mix(vec3<f32>(1.0), sky_light_tint(n), 0.4 * (1.0 - 0.5 * frame.sun_color.a));
++        sky_tint = mix(vec3<f32>(1.0), hue * shape, reach);
++    }
++    var light = max(base * sky_tint * frame.ambient.x, block * frame.ambient.y) * ao_ambient + direct;
++    // The mods' lights.
++    for (var k = 0u; k < surface_count; k++) {
++        let l = lights[select(tiles[surface_start + k], k, surface_all)];
++        let to = l.pos.xyz - p;
++        let dist = length(to);
++        if dist >= l.pos.w { continue; }
++        let window = pow(clamp(1.0 - pow(dist / l.pos.w, 4.0), 0.0, 1.0), 2.0);
++        let falloff = l.color.w / (dist * dist + 1.0) * window;
++        let k = max(dot(n, to / max(dist, 0.001)) * 0.85 + 0.15, 0.0);
++        light += l.color.rgb * falloff * k * ao_lights;
++    }
++    return albedo.rgb * light + albedo.rgb * albedo.a * 1.5;
++}
++
+ @fragment
+-fn fs_light(in: FullOut) -> @location(0) vec4<f32> {
++fn fs_light(in: FullOut) -> LightOut {
+     let px = vec2<i32>(in.position.xy);
+     let scene = textureLoad(scene_color, px, 0).rgb;
+     let d = textureLoad(scene_depth, px, 0);
+     let g = textureLoad(gbuffer_depth, px, 0);
+-    // Water in front of the opaque world with nothing translucent over it: here the floor is lit
+-    // and the water composite lays the surface over it (it knows the pixel by the alpha 0.5).
+-    var water = false;
+-    if frame.water.x > 0.5 && g > 0.0 {
+-        let wd = textureLoad(water_depth, px, 0);
+-        water = wd > 0.0 && wd >= g && d - wd <= d * 0.002;
+-    }
+-    let dd = select(d, g, water);
++    // Water over the opaque world (or over nothing): the water composite lays the surface over
++    // the floor, which is lit here with no air. Something translucent in front of the water
++    // (`front`: nearer than its surface) keeps the scene as drawn; the floor goes beside it.
++    var wd = 0.0;
++    var water_here = false;
++    if frame.water.x > 0.5 {
++        wd = textureLoad(water_depth, px, 0);
++        water_here = wd > 0.0 && (g <= 0.0 || wd >= g);
++    }
++    let front = water_here && g > 0.0 && d - wd > d * 0.002;
++    let water = water_here && !front;
++    let has_floor = water && g > 0.0;
++    let dd = select(d, g, has_floor);
+     let ndc = vec4<f32>(in.uv.x * 2.0 - 1.0, 1.0 - in.uv.y * 2.0, max(dd, 0.000001), 1.0);
+     let h = frame.inverse_view_proj * ndc;
+     let p = h.xyz / h.w;
+     let view = normalize(p);
++    // Where the air ends: the water's surface over water, else the pixel itself.
++    var ps = p;
++    if water {
++        let hf = frame.inverse_view_proj * vec4<f32>(in.uv.x * 2.0 - 1.0, 1.0 - in.uv.y * 2.0, max(wd, 0.000001), 1.0);
++        ps = hf.xyz / hf.w;
++    }
++    let view_s = normalize(ps);
+     let sun = frame.sun.xyz;
+     let sun_on = frame.sun.w;
+     let count = u32(frame.params.x);
+     let tile = ((u32(px.y) >> 4u) * u32(frame.shadow.w) + (u32(px.x) >> 4u)) * 4u;
+-    let surface_start = tiles[tile];
+-    let surface_all = tiles[tile + 1u] == 0xffffffffu;
+-    let surface_count = select(tiles[tile + 1u], count, surface_all);
+     let halo_start = tiles[tile + 2u];
+     let halo_all = tiles[tile + 3u] == 0xffffffffu;
+     let halo_count = select(tiles[tile + 3u], count, halo_all);
+@@ -455,113 +532,81 @@ fn fs_light(in: FullOut) -> @location(0) vec4<f32> {
+             c = c * cl.a + cl.rgb;
+         }
+     }
+-    // Clouds (vanilla's, drawn into the world with depth but not into the G-buffer): lit by the low
+-    // sun's colour at dusk and dawn instead of vanilla's flat white.
+-    if atmosphere && frame.clouds.z < 0.5 && !water && d > 0.0 && g <= 0.0 && p.y > 8.0 && dot(p, p) > 2304.0 {
+-        let low = 1.0 - smoothstep(0.05, 0.5, frame.sky_sun.y);
+-        c = scene * mix(vec3<f32>(1.0), mix(frame.sun_color.rgb, vec3<f32>(1.0), 0.45) * 1.1, low * 0.7 * (1.0 - frame.sky_extra.z));
+-    }
+-    let surface = water || (d > 0.0 && abs(d - g) <= max(d, g) * 0.002);
++    // (Vanilla's clouds, when the volumetric ones are off, take the low sun's colour in their own
++    // pass: `vanilla_cloud_tint`, applied to their colour on the CPU.)
++    let surface = has_floor || (!water_here && d > 0.0 && abs(d - g) <= max(d, g) * 0.002);
+     if surface {
+-        let n = normalize(textureLoad(normal_tex, px, 0).xyz);
+-        let albedo = textureLoad(albedo_tex, px, 0);
+-        let lm = textureLoad(light_tex, px, 0).xy;
+-        // Vanilla's light (sky and blocks through the lightmap), shaded where the sun can't reach.
+-        let base = textureSampleLevel(lightmap, linear, clamp(vec2<f32>(lm.y, lm.x) * (15.0 / 16.0) + 0.5 / 16.0, vec2<f32>(0.5 / 16.0), vec2<f32>(15.5 / 16.0)), 0.0).rgb;
+-        let block = textureSampleLevel(lightmap, linear, vec2<f32>(lm.y * (15.0 / 16.0) + 0.5 / 16.0, 0.5 / 16.0), 0.0).rgb;
+-        let sky_reach = smoothstep(0.35, 0.95, lm.x);
+-        var s = 1.0;
+-        let ndl = dot(n, sun);
+-        if sun_on > 0.0 && ndl > 0.0 && sky_reach > 0.0 { s = shadow_taps(p, n, select(1, 0, water)) * cloud_shadow(p); } else { s = 0.0; }
+-        // Shadowed sky light (ambient) keeps vanilla's look, blocks' light stays as is; the sun adds
+-        // direct light by the face's angle.
+-        let direct = frame.sun_color.rgb * sun_on * max(ndl, 0.0) * s * sky_reach;
+-        // Contact shadows from the ambient occlusion: on the ambient and blocks' light fully, on
+-        // the mods' lights by half, not on the sun or on emission.
+-        var occlusion = 1.0;
+-        // (The water dims and blurs the floor under it: no occlusion there.)
+-        if frame.ambient.w > 0.0 && !water { occlusion = ao_at(px, length(p)); }
+-        let ao_ambient = mix(1.0, occlusion, frame.ambient.w);
+-        let ao_lights = mix(1.0, occlusion, frame.ambient.w * 0.5);
+-        // The sky's light is bluish from above and carries the horizon's colour from the sides;
+-        // faces turned up take more of it than the ones turned down.
+-        var sky_tint = vec3<f32>(1.0);
+-        if atmosphere {
+-            let reach = smoothstep(0.25, 0.9, lm.x);
+-            let up = clamp(n.y * 0.5 + 0.5, 0.0, 1.0);
+-            let shape = mix(0.66, 1.1, smoothstep(0.1, 1.0, up));
+-            let hue = mix(vec3<f32>(1.0), sky_light_tint(n), 0.4 * (1.0 - 0.5 * frame.sun_color.a));
+-            sky_tint = mix(vec3<f32>(1.0), hue * shape, reach);
+-        }
+-        var light = max(base * sky_tint * frame.ambient.x, block * frame.ambient.y) * ao_ambient + direct;
+-        // The mods' lights.
+-        for (var k = 0u; k < surface_count; k++) {
+-            let l = lights[select(tiles[surface_start + k], k, surface_all)];
+-            let to = l.pos.xyz - p;
+-            let dist = length(to);
+-            if dist >= l.pos.w { continue; }
+-            let window = pow(clamp(1.0 - pow(dist / l.pos.w, 4.0), 0.0, 1.0), 2.0);
+-            let falloff = l.color.w / (dist * dist + 1.0) * window;
+-            let k = max(dot(n, to / max(dist, 0.001)) * 0.85 + 0.15, 0.0);
+-            light += l.color.rgb * falloff * k * ao_lights;
+-        }
+-        c = albedo.rgb * light + albedo.rgb * albedo.a * 1.5;
+-        // Vanilla's fog over it again.
+-        let sph = length(p);
+-        let cyl = max(length(p.xz), abs(p.y));
+-        let f = max(linear_fog(sph, frame.fog.x, frame.fog.y), linear_fog(cyl, frame.fog.z, frame.fog.w));
+-        let haze = haze_colour(view);
+-        c = mix(c, haze, f * frame.fog_color.a);
+-        // Aerial perspective: far things take the horizon's colour a little before the fog does.
+-        if atmosphere && frame.fog.x > 1.0e6 {
+-            c = mix(c, haze, (1.0 - exp(-sph / 700.0)) * 0.5);
++        c = shade_surface(px, p, water);
++        // Vanilla's fog over it again (the water composite does it at the surface).
++        if !water {
++            let sph = length(p);
++            let cyl = max(length(p.xz), abs(p.y));
++            let f = max(linear_fog(sph, frame.fog.x, frame.fog.y), linear_fog(cyl, frame.fog.z, frame.fog.w));
++            let haze = haze_colour(view);
++            c = mix(c, haze, f * frame.fog_color.a);
++            // Aerial perspective: far things take the horizon's colour a little before the fog does.
++            if atmosphere && frame.fog.x > 1.0e6 {
++                c = mix(c, haze, (1.0 - exp(-sph / 700.0)) * 0.5);
++            }
+         }
+     }
+-    // The volumetric fog: the light the air scatters towards the camera (shafts through the trees,
+-    // mist, haze), and how much of the pixel it hides.
+-    let far = select(min(length(p), frame.shadow.z), frame.shadow.z, d <= 0.0);
++    // What lies behind a translucent thing in front of the water: the floor, lit.
++    var floor_lit = vec3<f32>(0.0);
++    if front {
++        let hg = frame.inverse_view_proj * vec4<f32>(in.uv.x * 2.0 - 1.0, 1.0 - in.uv.y * 2.0, max(g, 0.000001), 1.0);
++        floor_lit = shade_surface(px, hg.xyz / hg.w, true);
++    }
++    // The air between the camera and the pixel (the water's surface over water): the volumetric
++    // fog (what it hides, what it scatters), the sun's rays between the shadows, and the halos
++    // round the mods' lights. Over water they go to the composite, which lays them over the
++    // finished water; elsewhere over the pixel here.
++    var air_t = 1.0;
++    var air_s = vec3<f32>(0.0);
++    let far = select(min(length(ps), frame.shadow.z), frame.shadow.z, d <= 0.0);
+     let density = frame.ambient.z;
+     let volumetric = frame.vfog.x > 0.5 && atmosphere;
+     if volumetric {
+         var fog_len = 192.0;
+-        if d > 0.0 {
+-            var pf = p;
+-            if water {
+-                let hf = frame.inverse_view_proj * vec4<f32>(in.uv.x * 2.0 - 1.0, 1.0 - in.uv.y * 2.0, max(d, 0.000001), 1.0);
+-                pf = hf.xyz / hf.w;
+-            }
+-            fog_len = min(length(pf), 192.0);
+-        }
++        if d > 0.0 { fog_len = min(length(ps), 192.0); }
+         let fg = fog_at(px, fog_len);
+-        c = c * fg.a + fg.rgb;
++        air_t = fg.a;
++        air_s = fg.rgb;
+     }
+-    // Light in the air (without the volumetric fog): the sun's rays between the shadows; always the
+-    // halos round the mods' lights.
+     if !volumetric && sun_on > 0.0 && density > 0.0 {
+         let steps = 14;
+         let jitter = ign(in.position.xy);
+         var acc = 0.0;
+         for (var i = 0; i < steps; i++) {
+             let t = (f32(i) + jitter) / f32(steps) * far;
+-            acc += lit_at(view * t);
++            acc += lit_at(view_s * t);
+         }
+         // Henyey-Greenstein, forward scattering: brightest looking towards the sun.
+-        let cos_t = dot(view, sun);
++        let cos_t = dot(view_s, sun);
+         let gk = 0.6;
+         let phase = (1.0 - gk * gk) / pow(1.0 + gk * gk - 2.0 * gk * cos_t, 1.5) * 0.08;
+-        c += frame.sun_color.rgb * sun_on * (acc / f32(steps)) * phase * (1.0 - exp(-far * density));
++        air_s += frame.sun_color.rgb * sun_on * (acc / f32(steps)) * phase * (1.0 - exp(-far * density));
+     }
+     for (var k = 0u; k < halo_count; k++) {
+         let l = lights[select(tiles[halo_start + k], k, halo_all)];
+         // Nearest point of the view ray to the light, and the glow along the ray in front of it.
+-        let t0 = dot(l.pos.xyz, view);
+-        let hh = length(l.pos.xyz - view * t0) + 0.5;
++        let t0 = dot(l.pos.xyz, view_s);
++        let hh = length(l.pos.xyz - view_s * t0) + 0.5;
+         if hh > l.pos.w * 0.5 { continue; }
+         let a0 = atan((0.0 - t0) / hh);
+         let a1 = atan((far - t0) / hh);
+-        c += l.color.rgb * l.color.w * (a1 - a0) / hh * 0.004 * (0.3 + density * 300.0);
++        // Thicker air glows more round a light, but only so far: the mist at dusk and many fires
++        // at once would otherwise wash the picture out.
++        air_s += l.color.rgb * l.color.w * (a1 - a0) / hh * 0.004 * (0.3 + min(density * 300.0, 0.9));
++    }
++    var out: LightOut;
++    if water {
++        out.lit = vec4<f32>(c, 0.5);
++        out.air = vec4<f32>(air_s, air_t);
++    } else {
++        out.lit = vec4<f32>(c * air_t + air_s, select(1.0, 0.6, front));
++        out.air = vec4<f32>(floor_lit, 0.0);
+     }
+-    return vec4<f32>(c, select(1.0, 0.5, water));
++    return out;
+ }
+ "#;
+ 
+@@ -580,6 +625,9 @@ const REFLECT_RANGE: f32 = 96.0;
+ @group(0) @binding(8) var lightmap: texture_2d<f32>;
+ @group(0) @binding(9) var linear: sampler;
+ //SKY10
++// What the lighting left beside the lit world: over water the air in front of the surface (scattered
++// light, transmittance), in front of the water the lit floor.
++@group(0) @binding(11) var air_tex: texture_2d<f32>;
+ 
+ fn ign(px: vec2<f32>) -> f32 {
+     let p = px + vec2<f32>(5.588238 * frame.params.w);
+@@ -761,6 +809,9 @@ fn fs_water(in: FullOut) -> @location(0) vec4<f32> {
+     let px = vec2<i32>(in.position.xy);
+     let base = textureLoad(lit_tex, px, 0);
+     if base.a > 0.75 { return vec4<f32>(base.rgb, 1.0); }
++    // Alpha 0.6: something translucent stands in front of the water here (base is the scene).
++    let front = base.a > 0.55;
++    let aux = textureLoad(air_tex, px, 0);
+     let wd = textureLoad(water_depth, px, 0);
+     let g = textureLoad(gbuffer_depth, px, 0);
+     let tint = textureLoad(water_tint, px, 0);
+@@ -792,23 +843,35 @@ fn fs_water(in: FullOut) -> @location(0) vec4<f32> {
+     let volume_light = max(ambient * frame.ambient.x, block * frame.ambient.y) + frame.sun_color.rgb * sun_on * sunlit * 0.8;
+ 
+     // Refraction: where the ray through the waves meets the world, against where the flat surface
+-    // would send it (so still water looks as vanilla's and only the waves distort).
+-    let floor0 = position_at(in.uv, g);
+-    let depth0 = max(length(floor0) - dist, 0.0);
+-    let bent = refract(-v, n, 0.75) - refract(-v, geometric, 0.75);
++    // would send it (so still water looks as vanilla's and only the waves distort). Not where
++    // something translucent is in front of the water, nor onto texels that hold such a thing.
++    let has_floor = g > 0.0;
+     var uv_floor = in.uv;
+     var floor_z = g;
+-    let moved = project(floor0 + bent * min(depth0, 24.0));
+-    if moved.z > 0.0 && on_screen(moved.xy) {
+-        let z = textureLoad(gbuffer_depth, texel(moved.xy), 0);
+-        // Only what lies behind the water: not the bank or an entity in front of it.
+-        if z > 0.0 && z <= wd {
+-            uv_floor = moved.xy;
+-            floor_z = z;
++    if has_floor && !front {
++        let floor0 = position_at(in.uv, g);
++        let depth0 = max(length(floor0) - dist, 0.0);
++        let bent = refract(-v, n, 0.75) - refract(-v, geometric, 0.75);
++        let moved = project(floor0 + bent * min(depth0, 24.0));
++        if moved.z > 0.0 && on_screen(moved.xy) {
++            let z = textureLoad(gbuffer_depth, texel(moved.xy), 0);
++            // The four texels the filter blends: none may be a pixel with a translucent thing
++            // in front of the water.
++            let marks = textureGather(3, lit_tex, linear, moved.xy);
++            let tainted = any((marks > vec4<f32>(0.55)) & (marks < vec4<f32>(0.75)));
++            // Only what lies behind the water: not the bank or an entity in front of it.
++            if z > 0.0 && z <= wd && !tainted {
++                uv_floor = moved.xy;
++                floor_z = z;
++            }
+         }
+     }
+-    let thickness = clamp(length(position_at(uv_floor, floor_z)) - dist, 0.0, 48.0);
+-    let behind = textureSampleLevel(lit_tex, linear, uv_floor, 0.0).rgb;
++    var thickness = 48.0;
++    if has_floor {
++        thickness = clamp(length(position_at(uv_floor, floor_z)) - dist, 0.0, 48.0);
++    }
++    var behind = textureSampleLevel(lit_tex, linear, uv_floor, 0.0).rgb;
++    if front { behind = aux.rgb; }
+     // A deep, dark water: the biome's colour darkened and a little greyed, so it reads as
+     // depth rather than as bright paint.
+     let biome = clamp(tint.rgb, vec3<f32>(0.03), vec3<f32>(1.0));
+@@ -840,6 +903,13 @@ fn fs_water(in: FullOut) -> @location(0) vec4<f32> {
+     if frame.sky_sun.w > 0.5 && frame.fog.x > 1.0e6 {
+         c = mix(c, haze, (1.0 - exp(-dist / 700.0)) * 0.5);
+     }
++    if front {
++        // The scene as drawn, with the water's change to the floor laid under the translucent thing.
++        c = base.rgb + (c - aux.rgb) * 0.7;
++    } else {
++        // The air between the camera and the surface: volumetric fog, rays, halos.
++        c = c * aux.a + aux.rgb;
++    }
+     return vec4<f32>(max(c, vec3<f32>(0.0)), 1.0);
+ }
+ "#;
+@@ -1413,6 +1483,8 @@ pub struct Hd {
+     water_normal: wgpu::TextureView,
+     water_depth: wgpu::TextureView,
+     lit_water: wgpu::TextureView,
++    /// The lighting's second target: the air over water, the floor beside translucent things.
++    air: wgpu::TextureView,
+     water_layout: wgpu::BindGroupLayout,
+     water_pipeline: wgpu::RenderPipeline,
+     water_group: Option<((wgpu::TextureView, wgpu::Sampler), wgpu::BindGroup)>,
+@@ -1849,6 +1921,7 @@ impl Hd {
+                 FLOAT,
+                 SAMPLER,
+                 FLOAT,
++                UNFILTERED,
+             ]),
+         });
+         let sky_layout = device.create_bind_group_layout(&wgpu::BindGroupLayoutDescriptor {
+@@ -1961,15 +2034,39 @@ impl Hd {
+             },
+             alpha: wgpu::BlendComponent::REPLACE,
+         };
+-        let light_pipeline = fullscreen(
+-            device,
+-            "HD lighting",
+-            &light_layout,
+-            &light,
+-            "fs_light",
+-            HDR,
+-            None,
+-        );
++        let light_pipeline = {
++            let layout = device.create_pipeline_layout(&wgpu::PipelineLayoutDescriptor {
++                label: Some("HD lighting"),
++                bind_group_layouts: &[Some(&light_layout)],
++                ..Default::default()
++            });
++            let target = Some(wgpu::ColorTargetState {
++                format: HDR,
++                blend: None,
++                write_mask: wgpu::ColorWrites::ALL,
++            });
++            device.create_render_pipeline(&wgpu::RenderPipelineDescriptor {
++                label: Some("HD lighting"),
++                layout: Some(&layout),
++                vertex: wgpu::VertexState {
++                    module: &light,
++                    entry_point: Some("vs_full"),
++                    compilation_options: Default::default(),
++                    buffers: &[],
++                },
++                fragment: Some(wgpu::FragmentState {
++                    module: &light,
++                    entry_point: Some("fs_light"),
++                    compilation_options: Default::default(),
++                    targets: &[target.clone(), target],
++                }),
++                primitive: Default::default(),
++                depth_stencil: None,
++                multisample: Default::default(),
++                multiview_mask: None,
++                cache: None,
++            })
++        };
+         let prefilter = fullscreen(
+             device,
+             "HD bloom prefilter",
+@@ -2108,6 +2205,7 @@ impl Hd {
+             )
+             .view,
+             lit: target(device, "HD lit", [1, 1], HDR).view,
++            air: target(device, "HD air", [1, 1], HDR).view,
+             fx: target(device, "HD post", [1, 1], HDR).view,
+             water_tint: target(device, "HD water colour", [1, 1], WATER_TINT).view,
+             water_normal: target(device, "HD water normal", [1, 1], WATER_NORMAL).view,
+@@ -2199,6 +2297,7 @@ impl Hd {
+         self.levels = target(device, "HD light levels", size, LIGHT_LEVELS).view;
+         self.depth = target(device, "HD depth", size, wgpu::TextureFormat::Depth32Float).view;
+         self.lit = target(device, "HD lit", size, HDR).view;
++        self.air = target(device, "HD air", size, HDR).view;
+         self.fx = target(device, "HD post", size, HDR).view;
+         self.water_tint = target(device, "HD water colour", size, WATER_TINT).view;
+         self.water_normal = target(device, "HD water normal", size, WATER_NORMAL).view;
+@@ -2322,7 +2421,12 @@ impl Hd {
+             0.0
+         };
+         let frame = HdFrame {
+-            prev_view_proj: scene.prev_view_proj.to_cols_array_2d(),
++            prev_view_proj: if self.upscaling() {
++                scene.prev_view_proj
++            } else {
++                scene.prev_view_proj_jittered
++            }
++            .to_cols_array_2d(),
+             taa: [
+                 scene.camera_delta.x,
+                 scene.camera_delta.y,
+@@ -2685,15 +2789,28 @@ impl Hd {
+             return;
+         };
+         self.water_composited = false;
+-        Self::draw(
+-            encoder,
+-            "HD lighting",
+-            &self.lit,
+-            false,
+-            &self.light_pipeline,
+-            group,
+-            stamp(&mut self.timing, "hd lighting"),
+-        );
++        let clear = |view| {
++            Some(wgpu::RenderPassColorAttachment {
++                view,
++                resolve_target: None,
++                depth_slice: None,
++                ops: wgpu::Operations {
++                    load: wgpu::LoadOp::Clear(wgpu::Color::BLACK),
++                    store: wgpu::StoreOp::Store,
++                },
++            })
++        };
++        {
++            let mut pass = encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
++                label: Some("HD lighting"),
++                timestamp_writes: stamp(&mut self.timing, "hd lighting"),
++                color_attachments: &[clear(&self.lit), clear(&self.air)],
++                ..Default::default()
++            });
++            pass.set_pipeline(&self.light_pipeline);
++            pass.set_bind_group(0, group, &[]);
++            pass.draw(0..3, 0..1);
++        }
+     }
+ 
+     /// A bind group of consecutive bindings 0.., counted (`groups_last_frame`).
+@@ -2987,6 +3104,7 @@ impl Hd {
+                     wgpu::BindingResource::TextureView(lightmap.0),
+                     wgpu::BindingResource::Sampler(&self.sampler),
+                     wgpu::BindingResource::TextureView(&self.sky_lut),
++                    wgpu::BindingResource::TextureView(&self.air),
+                 ],
+             );
+             self.water_group = Some((key, group));
+@@ -3098,6 +3216,20 @@ pub fn light_of(scene: &HdScene) -> (glam::Vec3, f32, glam::Vec3) {
+     }
+ }
+ 
++/// The factor on vanilla's cloud colour that lights the clouds with the low sun's colour at dusk
++/// and dawn instead of a flat white. It is the clouds' own colour (the cloud pass gets it), not a
++/// guess from the depth buffer, so what stands behind a cloud cannot change it.
++pub fn vanilla_cloud_tint(scene: &HdScene) -> [f32; 3] {
++    let sun = scene.sun.normalize_or(glam::Vec3::Y);
++    let low = 1.0 - smooth(0.05, 0.5, sun.y);
++    let overcast = (scene.rain / 0.7).clamp(0.0, 1.0) * 0.85;
++    let (_, _, color) = light_of(scene);
++    let warm = color.lerp(glam::Vec3::ONE, 0.45) * 1.1;
++    let t = low * 0.7 * (1.0 - overcast);
++    let tint = glam::Vec3::ONE.lerp(warm, t);
++    [tint.x, tint.y, tint.z]
++}
++
+ /// The x of the sun's direction: positive in the morning, negative in the evening.
+ fn sun_dir_x(scene: &HdScene) -> f32 {
+     scene.sun.normalize_or(glam::Vec3::Y).x
+@@ -3201,6 +3333,37 @@ mod tests {
+         assert_eq!(seen.len(), 16);
+     }
+ 
++    #[test]
++    fn taa_history_lookup_follows_the_jittered_grid() {
++        // A static point under two frames' different Halton jitters: fs_taa finds this frame's
++        // point in the history by the previous frame's matrix *as drawn*, which lands on the pixel
++        // the previous frame wrote it to; the unjittered one is off by that frame's jitter.
++        let size = [1920u32, 1080];
++        let unjittered = Mat4::perspective_rh(1.0, 16.0 / 9.0, 0.05, 1000.0);
++        let to_uv = |m: Mat4, p: glam::Vec3| {
++            let c = m * p.extend(1.0);
++            [c.x / c.w * 0.5 + 0.5, 0.5 - c.y / c.w * 0.5]
++        };
++        let drawn = |frame: u32| {
++            let j = jitter(frame, size, 16);
++            Mat4::from_translation(glam::Vec3::new(j[0], j[1], 0.0)) * unjittered
++        };
++        let p = glam::Vec3::new(0.0, 0.0, -20.0);
++        for frame in 1..16 {
++            let prev = drawn(frame - 1);
++            // The pixel (in uv) the previous frame drew the point at: what the history holds there.
++            let wrote = to_uv(prev, p);
++            let old = to_uv(unjittered, p);
++            let err = [
++                (old[0] - wrote[0]).abs() * size[0] as f32,
++                (old[1] - wrote[1]).abs() * size[1] as f32,
++            ];
++            let pj = jitter(frame - 1, size, 16);
++            assert!((err[0] - pj[0].abs() * size[0] as f32 * 0.5).abs() < 1e-3);
++            assert!((err[1] - pj[1].abs() * size[1] as f32 * 0.5).abs() < 1e-3);
++        }
++    }
++
+     #[test]
+     fn jitter_covers_the_upscale_ratio() {
+         assert_eq!(jitter_count(1.0), 16);
+diff --git a/crates/horizon-client/src/gfx/hd_sky.rs b/crates/horizon-client/src/gfx/hd_sky.rs
+index ec55de4c8..dbe8c8853 100644
+--- a/crates/horizon-client/src/gfx/hd_sky.rs
++++ b/crates/horizon-client/src/gfx/hd_sky.rs
+@@ -283,6 +283,14 @@ fn vanilla_sunrise_weight(d: vec3<f32>) -> f32 {
+     let theta = radians(flip + 90.0);
+     let c = cos(theta);
+     let s = sin(theta);
++    // Above the horizon the fan reaches only the sun's side (x of the same sign as the apex's, -s)
++    // and rises at most alpha/3 per block of that distance (its rim stands 40*alpha high over a
++    // 120-block radius and the points above the horizon lie at least 120 * the share of the rim
++    // from the axis); anything else cannot hit it, so most of the sky skips the 16 triangles.
++    if d.y > 0.0 {
++        let side = -s * d.x;
++        if side <= 0.0 || d.y > alpha * (1.0 / 3.0) * side * 1.02 + 0.001 { return 0.0; }
++    }
+     var best = 0.0;
+     let apex = vanilla_rotate_x90(vec3<f32>(-100.0 * s, 100.0 * c, 0.0));
+     for (var i = 0; i < 16; i++) {
+diff --git a/crates/horizon-client/src/terrain.wgsl b/crates/horizon-client/src/terrain.wgsl
+index 0a2a6cdba..cb098a64a 100644
+--- a/crates/horizon-client/src/terrain.wgsl
++++ b/crates/horizon-client/src/terrain.wgsl
+@@ -22,6 +22,8 @@ struct Globals {
+     // Atlas rect of the current destroy stage (read by entity.wgsl).
+     crumbling_sprite: vec4<f32>,
+     outline_params: vec4<f32>,
++    // AirDef fork. x: the HD water draws the water (fs_translucent leaves vanilla's out).
++    hd_flags: vec4<f32>,
+     // Horizon Extras' dynamic lights: camera-relative position and level (dynamic_light.rs).
+     dynamic_lights: array<vec4<f32>, 16>,
+ }
+@@ -211,6 +213,12 @@ struct WaterOut {
+ @fragment fn fs_translucent(in: TerrainOut) -> @location(0) vec4<f32> {
+     let color = sprite(in.uv, in.layer & 0x7fffu) * in.color;
+     if color.a < 0.01 { discard; }
++    // The HD water composite draws the water itself: vanilla's stays out of the colour (alpha 0
++    // blends to nothing) but keeps its depth, which the lighting reads.
++    let layer = in.layer & 0x7fffu;
++    if globals.hd_flags.x > 0.5 && (layer == WATER_STILL || layer == WATER_FLOW) {
++        return vec4(0.0);
++    }
+     return apply_fog(color, in.spherical, in.cylindrical);
+ }
+ 
+diff --git a/crates/horizon-mod-sdk/wit/horizon.wit b/crates/horizon-mod-sdk/wit/horizon.wit
+index 8411ac9aa..5fa5e8a27 100644
+--- a/crates/horizon-mod-sdk/wit/horizon.wit
++++ b/crates/horizon-mod-sdk/wit/horizon.wit
+@@ -694,6 +694,11 @@ interface render {
+     /// Switches the HD lighting on or off for this mod's world, with its
+     /// exposure and bloom; off, the world is drawn as the game draws it.
+     set-lighting: func(lighting: lighting);
++    /// Shows the world at this time of day (AirDef fork): the sky, the sun
++    /// and moon, the sky light and the fog, as `day-time` ticks (24000 a day,
++    /// as `clock`). Only what the player sees changes: the world's own clock,
++    /// its saves and its rules do not. None shows the world's own time.
++    set-time-override: func(day-time: option<u64>);
+ }
+ 
+ /// What the game calls. Only the hooks `init` asks for are ever called.
+diff --git a/crates/horizon-mods/src/api_level.rs b/crates/horizon-mods/src/api_level.rs
+index 8cf350044..bc1ade067 100644
+--- a/crates/horizon-mods/src/api_level.rs
++++ b/crates/horizon-mods/src/api_level.rs
+@@ -7,13 +7,13 @@
+ //! version's level so the launcher can tell before it installs.
+ 
+ /// The newest level this Horizon serves.
+-pub const LEVEL: u32 = 12;
++pub const LEVEL: u32 = 13;
+ 
+ /// Every function the game offers mods, as `interface.function`, with its
+ /// level. Level 0 is the contract of Horizon 0.2.67 to 0.2.69. A new
+ /// function takes the next level and raises [`LEVEL`] (the `api_reference`
+ /// test fails until it is listed here).
+-pub const FUNCTIONS: [(&str, u32); 66] = [
++pub const FUNCTIONS: [(&str, u32); 67] = [
+     ("log.write", 0),
+     ("game.get-player", 0),
+     ("game.get-clock", 0),
+@@ -82,6 +82,8 @@ pub const FUNCTIONS: [(&str, u32); 66] = [
+     ("render.query-sections", 12),
+     ("render.sections", 12),
+     ("render.world-changes", 12),
++    // AirDef fork: a replay shows its recorded time of day.
++    ("render.set-time-override", 13),
+ ];
+ 
+ /// What the game's program carries so the launcher can read its level
+diff --git a/crates/horizon-mods/src/runtime.rs b/crates/horizon-mods/src/runtime.rs
+index 2189a99e1..fb6180f1c 100644
+--- a/crates/horizon-mods/src/runtime.rs
++++ b/crates/horizon-mods/src/runtime.rs
+@@ -507,6 +507,8 @@ struct State {
+     /// `render.set-lights` and `render.set-lighting` (AirDef fork).
+     lights: Vec<PointLight>,
+     lighting: Option<ModLighting>,
++    /// `render.set-time-override` (AirDef fork).
++    time_override: Option<u64>,
+     input: InputState,
+     browser: BrowserState,
+     /// Capability `storage`'s folder; made on first `set`.
+@@ -749,6 +751,7 @@ impl Mods {
+             views: Vec::new(),
+             lights: Vec::new(),
+             lighting: None,
++            time_override: None,
+             input: InputState::default(),
+             browser: BrowserState::default(),
+             data_dir,
+@@ -1334,6 +1337,12 @@ impl Mods {
+             .iter()
+             .find_map(|e| e.run.as_ref()?.store.data().lighting)
+     }
++    /// The time of day the first running mod asked to show, if any.
++    pub fn time_override(&self) -> Option<u64> {
++        self.entries
++            .iter()
++            .find_map(|e| e.run.as_ref()?.store.data().time_override)
++    }
+     /// The columns each running mod asked the ground height of, taken.
+     pub fn take_ground_queries(&mut self) -> Vec<(usize, Vec<(i32, i32)>)> {
+         self.entries
+@@ -2237,6 +2246,9 @@ impl render::Host for State {
+         };
+         self.lighting = Some(lighting);
+     }
++    fn set_time_override(&mut self, day_time: Option<u64>) {
++        self.time_override = day_time.map(|t| t.min(1 << 40));
++    }
+     fn query_ground(&mut self, columns: Vec<(i32, i32)>) {
+         let room = 512usize.saturating_sub(self.ground_queries.len());
+         self.ground_queries.extend(columns.into_iter().take(room));
+diff --git a/docs/api/mods-reference.md b/docs/api/mods-reference.md
+index 2afb5bf62..b58f863c2 100644
+--- a/docs/api/mods-reference.md
++++ b/docs/api/mods-reference.md
+@@ -646,6 +646,7 @@ The HD lighting (AirDef fork): the world lit per pixel by the mods' lights, in h
+ | `set-views` | `func(views: list<camera-view>)` | Replaces the mod's cameras: up to 8. A `view` shape shows one; the game renders up to three a frame, in turn. |
+ | `set-lights` | `func(lights: list<point-light>)` | Replaces the mod's lights: up to 512, interpolated per id between the last two calls. |
+ | `set-lighting` | `func(lighting: lighting)` | Switches the HD lighting on or off for this mod's world, with its exposure and bloom; off, the world is drawn as the game draws it. |
++| `set-time-override` | `func(day-time: option<u64>)` | Shows the world at this time of day (AirDef fork): the sky, the sun and moon, the sky light and the fog, as `day-time` ticks (24000 a day, as `clock`). Only what the player sees changes: the world's own clock, its saves and its rules do not. None shows the world's own time. |
+ 
+ ## `events`
+ 
+-- 
+2.54.0 (Apple Git-157)
+

tools/hd_bench.py

@@ -0,0 +1,589 @@
+#!/usr/bin/env python3
+"""Графический полигон HD (#44): фиксированные сцены, сравнение кадров, мерцание и GPU-бюджет.
+
+    python3 tools/hd_bench.py --list                         # сцены и их параметры
+    python3 tools/hd_bench.py                                # все сцены -> run-home-bench/out/<время>/
+    python3 tools/hd_bench.py --only polygon_noon            # одна сцена (годится и при занятой игре)
+    python3 tools/hd_bench.py --env HORIZON_HD_TAA=0 --out run-home-bench/out/taa-off
+    python3 tools/hd_bench.py --baseline run-home-bench/out/before --out run-home-bench/out/after
+
+Каждый прогон: свежая копия миров Polygon и Hills из run-home/saves в run-home-bench/home, мод airdef,
+игра офскрин на сокете run-home-bench/c.sock (одна за раз; чужой игре run-home/ctl.sock не мешаем).
+Для каждой сцены: время суток, ясная погода, телепорт, пауза на устаканивание, кадр, ещё один кадр
+(мерцание), `bench 4` (GPU avg, мс) и средние проходы из run-home-bench/c.log при HORIZON_SHADER_PACK_TIMING=1.
+Итог: report.md и results.json в папке вывода.
+
+Коды выхода: 0 — всё в порогах и бюджете; 1 — есть превышение; 2 — ошибка запуска или аргументов.
+Только стандартная библиотека; при установленном Pillow сравнение быстрее.
+"""
+import argparse
+import datetime
+import json
+import os
+import re
+import shutil
+import struct
+import subprocess
+import sys
+import time
+import zlib
+from dataclasses import asdict, dataclass
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parent.parent
+BENCH = ROOT / "run-home-bench"
+SOCK = BENCH / "c.sock"  # короткий путь: лимит Unix-сокета около 104 байт
+LOG = SOCK.with_suffix(".log")  # лог игры рядом с сокетом (как ctl.log в run-home)
+HOME = BENCH / "home"  # HORIZON_HOME одного прогона, пересоздаётся каждый раз
+CTL = ROOT / "horizon" / "target" / "fast" / "horizon-ctl"
+SAVES = ROOT / "run-home" / "saves"
+OTHER_SOCK = "run-home/ctl.sock"  # чужая игра (другой агент): только читаем, не трогаем
+DIFF_LEVEL = 20  # порог «заметной» разницы по каналу, из 255
+DIFF_GAIN = 6  # усиление разницы в diff-картинках
+TIMING_RE = re.compile(r"shader pack GPU time per pass .*?: (.*) = ([\d.]+)\s*$")
+
+
+@dataclass
+class Shot:
+    name: str
+    world: str
+    time: int  # время суток: 0 рассвет, 1000 утро, 6000 полдень, 12000 закат, 18000 полночь
+    pose: tuple  # x, y, z, yaw, pitch (телепорт `tp @s`)
+    note: str
+
+
+# Позы проверены в игре: полигон с техникой, река Hills (-26.5 72 0.5, взгляд на реку и холм), лес Hills на восток
+# перед сравнением и поправь здесь, если кадр не то, что написано в note.
+SHOTS = [
+    Shot("polygon_noon", "Polygon", 6000, (40.5, 76.0, 40.5, 135.0, 25.0),
+         "полигон с техникой, полдень, белые материалы"),
+    Shot("hills_river_noon", "Hills", 6000, (-26.5, 72.0, 0.5, -150.0, 8.0),
+         "река на Hills, полдень: вода, преломление, блики"),
+    Shot("hills_river_sunset", "Hills", 12000, (-26.5, 72.0, 0.5, -150.0, 8.0),
+         "река на Hills, закат: тинт неба и воды"),
+    Shot("hills_river_night", "Hills", 18000, (-26.5, 72.0, 0.5, -150.0, 8.0),
+         "река на Hills, ночь: луна, туман"),
+    Shot("forest_morning_sun", "Hills", 1000, (-26.5, 71.0, 0.5, -90.0, 3.0),
+         "лес на Hills, утро, взгляд на восток (солнце ~15 градусов над горизонтом)"),
+    Shot("sky_noon", "Polygon", 6000, (40.5, 76.0, 40.5, 0.0, -40.0),
+         "небо и облака, полдень, взгляд вверх"),
+]
+
+
+class BenchError(RuntimeError):
+    pass
+
+
+def die(msg, code=2):
+    print(f"hd_bench: {msg}", file=sys.stderr)
+    sys.exit(code)
+
+
+# --- процессы и игра -------------------------------------------------------------------------
+
+def pgrep(pattern):
+    return subprocess.run(["pgrep", "-f", pattern], capture_output=True).returncode == 0
+
+
+def ctl_ok(*args):
+    r = subprocess.run([str(CTL), "--socket", str(SOCK), "--timeout", "3", *args],
+                       capture_output=True, text=True, timeout=20)
+    return r.returncode == 0
+
+
+def bench_running():
+    """Наша игра на c.sock: по командной строке (--control-socket) или по живому сокету."""
+    if pgrep(str(SOCK.relative_to(ROOT))):
+        return True
+    if SOCK.exists():
+        if ctl_ok("status"):
+            return True
+        SOCK.unlink()  # мёртвый сокет от прошлого прогона
+    return False
+
+
+def ctl(*args, timeout=30.0):
+    cmd = [str(CTL), "--socket", str(SOCK), "--timeout", f"{timeout:g}", *map(str, args)]
+    try:
+        r = subprocess.run(cmd, capture_output=True, text=True, timeout=timeout + 60)
+    except subprocess.TimeoutExpired as e:
+        raise BenchError(f"horizon-ctl {' '.join(map(str, args))}: таймаут") from e
+    if r.returncode != 0:
+        raise BenchError(f"horizon-ctl {' '.join(map(str, args))}: "
+                         f"{(r.stdout or r.stderr).strip()[:300]}")
+    return r.stdout.strip()
+
+
+def game_env(extra, timing):
+    env = dict(os.environ)
+    env.update({
+        "HORIZON_HOME": str(HOME),
+        "HORIZON_NO_AUDIO": "1",
+        "HORIZON_LAUNCHER_NO_SELF_UPDATE": "1",
+    })
+    if timing:
+        env["HORIZON_SHADER_PACK_TIMING"] = "1"
+    env.update(extra)
+    return env
+
+
+def prepare_home():
+    if HOME.exists():
+        shutil.rmtree(HOME)
+    (HOME / "saves").mkdir(parents=True)
+    for world in sorted({s.world for s in SHOTS}):
+        src = SAVES / world
+        if not src.is_dir():
+            die(f"нет мира {src}")
+        shutil.copytree(src, HOME / "saves" / world,
+                        ignore=shutil.ignore_patterns("session.lock", "*.lock"))
+
+
+def install_mod(env):
+    subprocess.run([sys.executable, str(ROOT / "tools" / "airdef.py"), "install"],
+                   env={**env, "HORIZON_HOME": str(HOME)}, check=True, cwd=ROOT)
+
+
+def launch(world, env, game, resources):
+    if SOCK.exists():
+        SOCK.unlink()
+    cmd = [str(CTL), "--socket", str(SOCK), "launch", "--world", world, "--offscreen", "--wait",
+           "--game", str(game), "--resources", str(resources)]
+    r = subprocess.run(cmd, capture_output=True, text=True, env=env, cwd=HOME, timeout=600)
+    if r.returncode != 0:
+        raise BenchError(f"launch {world}: {(r.stdout or r.stderr).strip()[:400]}")
+    ctl("command", "gamemode creative")
+    ctl("key", "t", "tap")  # чат, как игрок: /airdef shader hd
+    ctl("type", "/airdef shader hd")
+    ctl("key", "return", "tap")
+    time.sleep(0.5)
+    ctl("key", "f1", "tap")  # скрыть HUD (один раз на запуск)
+
+
+def stop_game():
+    try:
+        ctl("quit", timeout=20)
+    except BenchError:
+        pass
+    for _ in range(100):
+        if not ctl_ok("status"):
+            break
+        time.sleep(0.2)
+    if SOCK.exists() and not ctl_ok("status"):
+        SOCK.unlink()
+
+
+# --- кадры: PNG без Pillow и с ним -------------------------------------------------------------
+
+def _paeth(a, b, c):
+    p = a + b - c
+    pa, pb, pc = abs(p - a), abs(p - b), abs(p - c)
+    return a if pa <= pb and pa <= pc else (b if pb <= pc else c)
+
+
+def read_png_rgb(path):
+    """(w, h, bytes RGB). Только 8-бит RGB/RGBA без чередования (так пишет игра)."""
+    data = Path(path).read_bytes()
+    if data[:8] != b"\x89PNG\r\n\x1a\n":
+        raise BenchError(f"{path}: не PNG")
+    pos, idat, w = 8, [], 0
+    while pos < len(data):
+        (ln,) = struct.unpack(">I", data[pos:pos + 4])
+        kind = data[pos + 4:pos + 8]
+        body = data[pos + 8:pos + 8 + ln]
+        pos += 12 + ln
+        if kind == b"IHDR":
+            w, h, depth, ctype, _, _, interlace = struct.unpack(">IIBBBBB", body)
+        elif kind == b"IDAT":
+            idat.append(body)
+        elif kind == b"IEND":
+            break
+    if depth != 8 or interlace or ctype not in (2, 6):
+        raise BenchError(f"{path}: нужен 8-бит RGB/RGBA без чередования")
+    bpp = 3 if ctype == 2 else 4
+    stride = w * bpp
+    raw = zlib.decompress(b"".join(idat))
+    out = bytearray(w * h * 3)
+    prev = bytearray(stride)
+    p = 0
+    for y in range(h):
+        ft = raw[p]
+        line = raw[p + 1:p + 1 + stride]
+        p += 1 + stride
+        cur = bytearray(stride)
+        for i in range(stride):
+            x = line[i]
+            a = cur[i - bpp] if i >= bpp else 0
+            b = prev[i]
+            c = prev[i - bpp] if i >= bpp else 0
+            if ft == 1:
+                x += a
+            elif ft == 2:
+                x += b
+            elif ft == 3:
+                x += (a + b) >> 1
+            elif ft == 4:
+                x += _paeth(a, b, c)
+            cur[i] = x & 255
+        base = y * w * 3
+        if bpp == 3:
+            out[base:base + w * 3] = cur
+        else:
+            out[base:base + w * 3:3] = cur[0::4]
+            out[base + 1:base + w * 3:3] = cur[1::4]
+            out[base + 2:base + w * 3:3] = cur[2::4]
+        prev = cur
+    return w, h, bytes(out)
+
+
+def write_png_rgb(path, w, h, rgb):
+    raw = b"".join(b"\x00" + rgb[y * w * 3:(y + 1) * w * 3] for y in range(h))
+
+    def chunk(kind, body):
+        return struct.pack(">I", len(body)) + kind + body + struct.pack(">I", zlib.crc32(kind + body) & 0xFFFFFFFF)
+
+    Path(path).write_bytes(b"\x89PNG\r\n\x1a\n"
+                           + chunk(b"IHDR", struct.pack(">IIBBBBB", w, h, 8, 2, 0, 0, 0))
+                           + chunk(b"IDAT", zlib.compress(raw, 6))
+                           + chunk(b"IEND", b""))
+
+
+try:  # необязательно: быстрее декодирование и сравнение
+    from PIL import Image, ImageChops, ImageStat
+except ImportError:  # pragma: no cover
+    Image = None
+
+
+def compare_frames(a, b, diff_out=None):
+    """Средняя разница по каналам (0..255) и доля пикселей с разницей > DIFF_LEVEL, в %."""
+    if Image is not None:
+        A = Image.open(a).convert("RGB")
+        B = Image.open(b).convert("RGB")
+        if A.size != B.size:
+            raise BenchError(f"размеры кадров разные: {A.size} и {B.size}")
+        d = ImageChops.difference(A, B)
+        mean = sum(ImageStat.Stat(d).mean) / 3
+        r, g, bl = d.split()
+        mx = ImageChops.lighter(ImageChops.lighter(r, g), bl)
+        hist = mx.histogram()
+        total = A.size[0] * A.size[1]
+        pct = 100.0 * sum(hist[DIFF_LEVEL + 1:]) / total
+        if diff_out:
+            d.point(lambda v: min(255, v * DIFF_GAIN)).save(diff_out)
+        return {"mean": mean, "pct": pct, "size": list(A.size)}
+    wa, ha, pa = read_png_rgb(a)
+    wb, hb, pb = read_png_rgb(b)
+    if (wa, ha) != (wb, hb):
+        raise BenchError(f"размеры кадров разные: {wa}x{ha} и {wb}x{hb}")
+    total_abs = 0
+    over = 0
+    diff = bytearray(len(pa)) if diff_out else None
+    for i in range(0, len(pa), 3):
+        dr = abs(pa[i] - pb[i])
+        dg = abs(pa[i + 1] - pb[i + 1])
+        db = abs(pa[i + 2] - pb[i + 2])
+        total_abs += dr + dg + db
+        if max(dr, dg, db) > DIFF_LEVEL:
+            over += 1
+        if diff is not None:
+            diff[i] = min(255, dr * DIFF_GAIN)
+            diff[i + 1] = min(255, dg * DIFF_GAIN)
+            diff[i + 2] = min(255, db * DIFF_GAIN)
+    if diff_out:
+        write_png_rgb(diff_out, wa, ha, bytes(diff))
+    npx = wa * ha
+    return {"mean": total_abs / (3.0 * npx), "pct": 100.0 * over / npx, "size": [wa, ha]}
+
+
+# --- тайминги -----------------------------------------------------------------------------------
+
+def read_from(path, offset):
+    try:
+        with open(path, "rb") as f:
+            f.seek(offset)
+            return f.read().decode("utf-8", "replace")
+    except FileNotFoundError:
+        return ""
+
+
+def parse_pass_reports(text):
+    reports = []
+    for line in text.splitlines():
+        m = TIMING_RE.search(line)
+        if not m:
+            continue
+        passes = {}
+        for part in m.group(1).split(", "):
+            name, _, ms = part.rpartition(" ")
+            try:
+                passes[name] = float(ms)
+            except ValueError:
+                pass
+        reports.append((passes, float(m.group(2))))
+    return reports
+
+
+def average_passes(reports):
+    if not reports:
+        return {}, None
+    sums, counts = {}, {}
+    for passes, _ in reports:
+        for name, ms in passes.items():
+            sums[name] = sums.get(name, 0.0) + ms
+            counts[name] = counts.get(name, 0) + 1
+    avg = {n: sums[n] / counts[n] for n in sums}
+    total = sum(avg.values())
+    return avg, total
+
+
+def bench_gpu_avg(reply):
+    try:
+        return float(json.loads(reply)["gpu"]["avg_ms"])
+    except (ValueError, KeyError, TypeError):
+        return None
+
+
+# --- сцена ------------------------------------------------------------------------------------
+
+def run_shot(shot, out, settle, bench_secs, timing):
+    x, y, z, yaw, pitch = shot.pose
+    ctl("command", f"time set {shot.time}")
+    ctl("command", "weather clear")
+    ctl("command", f"tp @s {x} {y} {z} {yaw} {pitch}")
+    ctl("wait-ready", 120, timeout=150)
+    time.sleep(settle)
+    first = out / f"{shot.name}.png"
+    ctl("screenshot", str(first.resolve()))
+    time.sleep(0.5)
+    second = out / f"{shot.name}_still2.png"
+    ctl("screenshot", str(second.resolve()))
+    result = {"frame": first.name, "still2": second.name, "gpu_avg_ms": None, "passes": {},
+              "pass_total_ms": None, "bench_json": None}
+    offset = LOG.stat().st_size if LOG.exists() else 0
+    reply = ctl("bench", bench_secs, timeout=bench_secs + 60)
+    (out / f"{shot.name}_bench.json").write_text(reply + "\n")
+    result["bench_json"] = f"{shot.name}_bench.json"
+    result["gpu_avg_ms"] = bench_gpu_avg(reply)
+    if timing:
+        time.sleep(1.0)  # последний отчёт о проходах
+        reports = parse_pass_reports(read_from(LOG, offset))
+        result["passes"], result["pass_total_ms"] = average_passes(reports)
+        if not reports:
+            result["warning"] = "нет строк проходов в логе (мало таймед-кадров?)"
+    return result
+
+
+def group_by_world(shots):
+    order = []
+    for s in shots:
+        if s.world not in order:
+            order.append(s.world)
+    return [(w, [s for s in shots if s.world == w]) for w in order]
+
+
+def git_rev():
+    r = subprocess.run(["git", "-C", str(ROOT), "rev-parse", "--short", "HEAD"],
+                       capture_output=True, text=True)
+    return r.stdout.strip() or "?"
+
+
+def judge(entry, args):
+    reasons = []
+    if entry.get("error"):
+        reasons.append("ошибка: " + entry["error"])
+    gpu = entry.get("gpu_avg_ms")
+    if gpu is not None and gpu > args.budget_ms:
+        reasons.append(f"GPU {gpu:.2f} мс > бюджета {args.budget_ms:g}")
+    if gpu is None and not entry.get("error"):
+        reasons.append("нет GPU-таймингов (bench)")
+    fl = entry.get("flicker")
+    if fl and fl["pct"] > args.max_flicker:
+        reasons.append(f"мерцание {fl['pct']:.2f}% > {args.max_flicker:g}%")
+    base = entry.get("vs_baseline")
+    if base:
+        if base.get("error"):
+            reasons.append(base["error"])
+        else:
+            if base["mean"] > args.max_mean:
+                reasons.append(f"разница с базой {base['mean']:.2f} > {args.max_mean:g}")
+            if base["pct"] > args.max_pct:
+                reasons.append(f"пикселей >20/255 {base['pct']:.2f}% > {args.max_pct:g}%")
+    return reasons
+
+
+def write_report(out, entries, args, env_extra, size, baseline):
+    lines = []
+    add = lines.append
+    add(f"# HD-полигон: {out.name}")
+    add("")
+    add(f"- коммит: `{git_rev()}`, дата: {datetime.datetime.now():%Y-%m-%d %H:%M}")
+    add(f"- разрешение кадра: {size[0]}x{size[1]}" if size else "- разрешение кадра: ?")
+    add(f"- окружение игры: " + (", ".join(f"`{k}={v}`" for k, v in sorted(env_extra.items())) or "по умолчанию"))
+    add(f"- бюджет GPU: {args.budget_ms:g} мс (bench {args.bench_secs:g} с), мерцание <= {args.max_flicker:g}%")
+    if baseline:
+        add(f"- сравнение с: `{baseline}` (средняя разница <= {args.max_mean:g}, пикселей >20/255 <= {args.max_pct:g}%)")
+    add("")
+    add("| сцена | мир | время | GPU avg, мс | бюджет | мерцание %>20 | к базе: mean | к базе: %>20 | итог |")
+    add("|---|---|---|---|---|---|---|---|---|")
+    for e in entries:
+        gpu = f"{e['gpu_avg_ms']:.2f}" if e.get("gpu_avg_ms") is not None else "-"
+        fl = f"{e['flicker']['pct']:.2f}" if e.get("flicker") else "-"
+        b = e.get("vs_baseline") or {}
+        bm = f"{b['mean']:.2f}" if "mean" in b else "-"
+        bp = f"{b['pct']:.2f}" if "pct" in b else "-"
+        status = "OK" if not e["fail"] else "FAIL: " + "; ".join(e["fail"])
+        budget = "да" if e.get("gpu_avg_ms") is not None and e["gpu_avg_ms"] <= args.budget_ms else ("нет" if e.get("gpu_avg_ms") is not None else "-")
+        add(f"| {e['name']} | {e['world']} | {e['time']} | {gpu} | {budget} | {fl} | {bm} | {bp} | {status} |")
+    passes = []
+    for e in entries:
+        for p in e.get("passes", {}):
+            if p not in passes:
+                passes.append(p)
+    if passes:
+        add("")
+        add("## Проходы GPU, среднее по отчётам лога, мс")
+        add("")
+        add("| проход | " + " | ".join(e["name"] for e in entries) + " |")
+        add("|---|" + "---|" * len(entries))
+        for p in passes:
+            add(f"| {p} | " + " | ".join(f"{e['passes'][p]:.3f}" if p in e.get("passes", {}) else "-" for e in entries) + " |")
+        totals = [f"{e['pass_total_ms']:.3f}" if e.get("pass_total_ms") is not None else "-" for e in entries]
+        add("| **итого** | " + " | ".join(totals) + " |")
+    add("")
+    add("## Кадры")
+    for e in entries:
+        add("")
+        add(f"### {e['name']}: {e['note']}")
+        add("")
+        add(f"![{e['name']}]({e['frame']})")
+        if e.get("diff_image"):
+            add("")
+            add(f"Разница с базой (x{DIFF_GAIN}): ![diff]({e['diff_image']})")
+        if e.get("warning"):
+            add("")
+            add(f"> {e['warning']}")
+        if e.get("error"):
+            add("")
+            add(f"> ошибка: {e['error']}")
+    (out / "report.md").write_text("\n".join(lines) + "\n")
+
+
+def parse_args(argv):
+    p = argparse.ArgumentParser(description="Графический полигон HD: кадры, мерцание, GPU-бюджет.")
+    p.add_argument("--list", action="store_true", help="показать сцены и выйти")
+    p.add_argument("--only", action="append", default=[], metavar="СЦЕНА", help="только эти сцены (можно несколько раз)")
+    p.add_argument("--out", help="папка вывода (по умолчанию run-home-bench/out/<время>)")
+    p.add_argument("--baseline", help="папка прошлого прогона для сравнения кадров")
+    p.add_argument("--env", action="append", default=[], metavar="КЛЮЧ=ЗНАЧЕНИЕ", help="переменная для игры, например HORIZON_HD_TAA=0")
+    p.add_argument("--budget-ms", type=float, default=18.0, help="бюджет GPU на кадр, мс (по умолчанию 18)")
+    p.add_argument("--bench-secs", type=float, default=4.0, help="сколько секунд bench (по умолчанию 4)")
+    p.add_argument("--settle", type=float, default=4.0, help="пауза после телепорта, с (по умолчанию 4)")
+    p.add_argument("--max-mean", type=float, default=3.0, help="порог средней разницы с базой, 0..255")
+    p.add_argument("--max-pct", type=float, default=5.0, help="порог пикселей >20/255 с базой, %%")
+    p.add_argument("--max-flicker", type=float, default=5.0, help="порог мерцания (два кадра подряд), %%")
+    p.add_argument("--no-pass-timing", action="store_true", help="не включать HORIZON_SHADER_PACK_TIMING")
+    p.add_argument("--game", help="horizon-client (по умолчанию как в tools/airdef.py)")
+    p.add_argument("--resources", help="подготовленные ресурсы Minecraft 26.3")
+    return p.parse_args(argv)
+
+
+def main(argv=None):
+    args = parse_args(argv)
+    if args.list:
+        for s in SHOTS:
+            print(f"{s.name:22} {s.world:8} время {s.time:5}  поза {s.pose}  {s.note}")
+        return 0
+    shots = [s for s in SHOTS if not args.only or s.name in args.only]
+    unknown = set(args.only) - {s.name for s in SHOTS}
+    if unknown:
+        die(f"нет сцен: {', '.join(sorted(unknown))} (см. --list)")
+    env_extra = {}
+    for item in args.env:
+        if "=" not in item:
+            die(f"--env ждёт КЛЮЧ=ЗНАЧЕНИЕ, получено: {item}")
+        k, v = item.split("=", 1)
+        env_extra[k] = v
+    if bench_running():
+        die("уже запущена игра на run-home-bench/c.sock: один прогон за раз")
+    if pgrep(OTHER_SOCK):
+        if len(shots) > 1:
+            die(f"работает чужая игра на {OTHER_SOCK}: запусти одну сцену (--only) или дождись конца теста")
+        print(f"hd_bench: внимание: работает чужая игра на {OTHER_SOCK}, снимок будет под нагрузкой",
+              file=sys.stderr)
+    out = Path(args.out) if args.out else BENCH / "out" / datetime.datetime.now().strftime("%Y%m%d-%H%M%S")
+    out = out.resolve()
+    out.mkdir(parents=True, exist_ok=True)
+    sys.path.insert(0, str(ROOT / "tools"))
+    import airdef  # tools/airdef.py: ресурсы и путь к игре
+
+    game = Path(args.game) if args.game else airdef.built_game()
+    resources = Path(args.resources) if args.resources else airdef.resources()
+    timing = not args.no_pass_timing
+    env = game_env(env_extra, timing)
+    prepare_home()
+    install_mod(env)
+
+    entries = []
+    baseline = Path(args.baseline).resolve() if args.baseline else None
+    try:
+        for world, group in group_by_world(shots):
+            try:
+                launch(world, env, game, resources)
+            except BenchError as e:
+                for s in group:
+                    entries.append({**asdict(s), "error": str(e), "fail": [f"ошибка: {e}"]})
+                stop_game()
+                continue
+            for s in group:
+                entry = {**asdict(s), "frame": f"{s.name}.png"}
+                try:
+                    entry.update(run_shot(s, out, args.settle, args.bench_secs, timing))
+                    fl = compare_frames(out / f"{s.name}.png", out / f"{s.name}_still2.png")
+                    entry["flicker"] = fl
+                except BenchError as e:
+                    entry["error"] = str(e)
+                if baseline and not entry.get("error"):
+                    base_png = baseline / f"{s.name}.png"
+                    if base_png.exists():
+                        try:
+                            diff_name = f"{s.name}_diff.png"
+                            m = compare_frames(base_png, out / f"{s.name}.png", out / diff_name)
+                            entry["vs_baseline"] = m
+                            entry["diff_image"] = diff_name
+                        except BenchError as e:
+                            entry["vs_baseline"] = {"error": str(e)}
+                    else:
+                        entry["vs_baseline"] = {"error": f"в базе нет {base_png.name}"}
+                entry["fail"] = judge(entry, args)
+                entries.append(entry)
+            stop_game()
+    finally:
+        stop_game()
+
+    size = None
+    for e in entries:
+        if e.get("vs_baseline") and "size" in e["vs_baseline"]:
+            size = e["vs_baseline"]["size"]
+            break
+    if size is None and entries and entries[0].get("flicker"):
+        size = entries[0]["flicker"]["size"]
+    results = {"out": str(out), "env": env_extra, "budget_ms": args.budget_ms,
+               "baseline": str(baseline) if baseline else None, "shots": entries}
+    (out / "results.json").write_text(json.dumps(results, ensure_ascii=False, indent=2) + "\n")
+    write_report(out, entries, args, env_extra, size, str(baseline) if baseline else None)
+
+    failed = [e for e in entries if e["fail"]]
+    for e in entries:
+        print(f"{e['name']:22} GPU {e.get('gpu_avg_ms') if e.get('gpu_avg_ms') is None else round(e['gpu_avg_ms'], 2)} мс  "
+              f"мерцание {e['flicker']['pct']:.2f}%" if e.get("flicker") else f"{e['name']:22} {e.get('error', '')}")
+        for r in e["fail"]:
+            print(f"    FAIL: {r}")
+    print(f"отчёт: {out / 'report.md'}")
+    return 1 if failed else 0
+
+
+if __name__ == "__main__":
+    try:
+        sys.exit(main())
+    except BenchError as e:
+        die(str(e), code=2)