Continuous engine sound on drones and missiles, live and in replays, through persistent sound sources (#95, fork patch 37)

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

README.md

@@ -221,6 +221,12 @@ API мода `render.set-lights` (до 512, плавно интерполиру
 У каждого объекта свой звук и своя дальность слышимости (`attenuation_distance` в `sounds.json`):
 - **двигатели:** двухтактный мопед шахеда (220 м), турбина Герани-3, электромотор Ланцета, тяжёлый рёв крылатых ракет (320 м),
   ракетный рёв Х-22, Циркона и перехватчиков, нарастающий визг падающей баллистики и её ударная волна (700–900 м);
+  Двигатели дронов и ракет — **постоянные источники звука** (API 20, `render.sound-sources`, #95): один источник на
+  объект идёт за его настоящей позицией, зажигается с нарастанием, при сбитии «захлёбывается» (тон падает, громкость
+  гаснет за секунду) и замолкает вместе с объектом; в повторе и экспорте источники берутся из записанных траекторий и
+  времени повтора (перемотка и смена плана пересоздают их). Одновременно звучат 24 ближайших и громких, остальные
+  «виртуальные». Взрывы, пуски и выстрелы остались разовыми, с задержкой по скорости звука. Баллистика (визг при
+  падении) тоже разовая. Зацикливается устойчивая часть файла (начало и затухание в конце обрезаны), стык — 50 мс.
 - **пуски:** хлопок и рвущийся рёв Patriot, свистящий старт Панциря, глухой газовый выброс и затем огромный рёв С-400,
   у С-500 ещё ниже и дольше (до 1 км);
 - **пушки:** тяжёлые 35-мм очереди Гепарда и частые 30-мм Панциря;

airdef-mod/src/engines.rs

@@ -0,0 +1,330 @@
+//! Engines as persistent sound sources (#95): a drone's or a missile's engine is one source that
+//! follows the entity, instead of a one-shot repeated every second or two.
+//!
+//! The simulation (live) and the replay (from a recording's tracks and the replay's time) each
+//! *declare* the engines sounding this tick; [`Engines::step`] turns that into the changes of
+//! `render.sound-sources`: a start with an attack when an engine appears (ignition), an update
+//! every tick, a stop with a release when it is gone (burnout, the entity removed), and a fall
+//! of pitch and gain over a second when it is damaged (a drone shot down). A declaration missing
+//! for a tick or two (a step the simulation skipped) does not stop the sound; a *cut* (a replay
+//! seek, a new shot) stops every engine and starts them again under new ids, so nothing glides
+//! across the jump.
+use glam::DVec3;
+use std::collections::{BTreeMap, BTreeSet};
+
+/// Ticks an engine may go undeclared before it is stopped.
+const GRACE: u32 = 3;
+/// Ticks a damaged engine takes to die: its pitch falls and it fades.
+const DYING: u32 = 20;
+/// The most engines that sound at once (the nearest ones; the game's budget picks the audible).
+const MAX: usize = 128;
+/// Doppler applied to engines. The kinds already differ in pitch, and the fight's speed must not
+/// change what is heard, so it stays off; the game bounds it to 12% anyway.
+pub const DOPPLER: f32 = 0.0;
+
+/// An engine that sounds this tick.
+#[derive(Clone, Debug, PartialEq)]
+pub struct Decl {
+    /// The entity: a drone's id, a missile's with a high bit, a replay track's with another.
+    pub key: u32,
+    pub event: &'static str,
+    pub at: DVec3,
+    /// Blocks a second.
+    pub vel: DVec3,
+    pub gain: f32,
+    pub pitch: f32,
+    /// Shot down: the engine dies away.
+    pub damaged: bool,
+}
+
+/// What a source is asked to be.
+#[derive(Clone, Debug, PartialEq)]
+pub struct Voice {
+    pub event: &'static str,
+    pub at: DVec3,
+    pub vel: DVec3,
+    pub gain: f32,
+    pub pitch: f32,
+    pub attack: f32,
+    pub release: f32,
+    pub loop_from: f32,
+    pub loop_to: f32,
+}
+
+/// One change of `render.sound-sources`.
+#[derive(Clone, Debug, PartialEq)]
+pub enum Op {
+    Start(u32, Voice),
+    Update(u32, Voice),
+    Stop(u32),
+}
+
+/// The steady part of each engine sound, seconds into the file: the sounds fade in at their start
+/// and die away at their end (synthesis, reverb tail, fade: tools/gen_sounds.py), so looping a
+/// whole file leaves a gap; these were found as `audio::tests::a_loop_of_the_steady_part_of_the_
+/// engine_sounds_has_no_hole` finds them (after the fade-in, before the sound begins to die).
+pub fn steady_part(event: &str) -> (f32, f32) {
+    match event {
+        "airdef:drone.shahed" => (0.2, 2.2),
+        "airdef:drone.geran3" => (0.2, 2.0),
+        "airdef:drone.lancet" => (0.2, 1.4),
+        "airdef:drone.cruise" => (0.2, 2.6),
+        "airdef:drone.rocket" => (0.2, 2.6),
+        "airdef:missile.flight" => (0.2, 2.2),
+        _ => (0.0, 0.0),
+    }
+}
+
+struct Live {
+    id: u32,
+    event: &'static str,
+    missed: u32,
+    dying: u32,
+}
+
+#[derive(Default)]
+pub struct Engines {
+    live: BTreeMap<u32, Live>,
+    /// Engines that died and are still declared (a wreck falling): not started again.
+    dead: BTreeSet<u32>,
+    next_id: u32,
+}
+
+impl Engines {
+    pub fn is_empty(&self) -> bool {
+        self.live.is_empty()
+    }
+
+    /// The game released every source: forget them (nothing to stop).
+    pub fn reset(&mut self) {
+        self.live.clear();
+        self.dead.clear();
+    }
+
+    fn voice(d: &Decl, dying: u32) -> Voice {
+        let u = (dying as f32 / DYING as f32).min(1.0);
+        let (loop_from, loop_to) = steady_part(d.event);
+        Voice {
+            event: d.event,
+            at: d.at,
+            vel: d.vel,
+            // A shot-down engine coughs: the pitch falls by almost half, the sound fades.
+            gain: d.gain * (1.0 - u),
+            pitch: d.pitch * (1.0 - 0.45 * u),
+            attack: 0.3,
+            release: 0.25,
+            loop_from,
+            loop_to,
+        }
+    }
+
+    /// One tick: what is declared now, and whether the picture cut (a seek or a new shot).
+    pub fn step(&mut self, mut decls: Vec<Decl>, cut: bool, listener: DVec3) -> Vec<Op> {
+        let mut ops = Vec::new();
+        if cut {
+            for (_, l) in std::mem::take(&mut self.live) {
+                ops.push(Op::Stop(l.id));
+            }
+            self.dead.clear();
+        }
+        if decls.len() > MAX {
+            decls.sort_by(|a, b| {
+                a.at.distance_squared(listener)
+                    .total_cmp(&b.at.distance_squared(listener))
+                    .then(a.key.cmp(&b.key))
+            });
+            decls.truncate(MAX);
+        }
+        decls.sort_by_key(|d| d.key);
+        for l in self.live.values_mut() {
+            l.missed += 1;
+        }
+        let declared: BTreeSet<u32> = decls.iter().map(|d| d.key).collect();
+        self.dead.retain(|k| declared.contains(k));
+        for d in &decls {
+            if self.dead.contains(&d.key) {
+                continue;
+            }
+            match self.live.get_mut(&d.key) {
+                Some(l) if l.event == d.event => {
+                    l.missed = 0;
+                    if d.damaged {
+                        l.dying += 1;
+                    }
+                    if l.dying >= DYING {
+                        ops.push(Op::Stop(l.id));
+                        self.live.remove(&d.key);
+                        self.dead.insert(d.key);
+                    } else {
+                        ops.push(Op::Update(l.id, Self::voice(d, l.dying)));
+                    }
+                }
+                other => {
+                    // A new engine, or the same entity with another sound: the old one releases.
+                    if let Some(l) = other {
+                        ops.push(Op::Stop(l.id));
+                    }
+                    self.next_id = self.next_id.wrapping_add(1).max(1);
+                    let dying = u32::from(d.damaged);
+                    ops.push(Op::Start(self.next_id, Self::voice(d, dying)));
+                    self.live.insert(
+                        d.key,
+                        Live {
+                            id: self.next_id,
+                            event: d.event,
+                            missed: 0,
+                            dying,
+                        },
+                    );
+                }
+            }
+        }
+        // Gone for good: the entity was removed (burnout, a hit, a crash).
+        let gone: Vec<u32> = self
+            .live
+            .iter()
+            .filter(|(_, l)| l.missed > GRACE)
+            .map(|(k, _)| *k)
+            .collect();
+        for k in gone {
+            if let Some(l) = self.live.remove(&k) {
+                ops.push(Op::Stop(l.id));
+            }
+        }
+        ops
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn d(key: u32, x: f64) -> Decl {
+        Decl {
+            key,
+            event: "airdef:drone.shahed",
+            at: DVec3::new(x, 50.0, 0.0),
+            vel: DVec3::new(30.0, 0.0, 0.0),
+            gain: 0.8,
+            pitch: 1.0,
+            damaged: false,
+        }
+    }
+    fn starts(ops: &[Op]) -> usize {
+        ops.iter().filter(|o| matches!(o, Op::Start(..))).count()
+    }
+    fn stops(ops: &[Op]) -> usize {
+        ops.iter().filter(|o| matches!(o, Op::Stop(_))).count()
+    }
+
+    #[test]
+    fn an_engine_ignites_follows_and_stops_when_its_entity_goes() {
+        let mut e = Engines::default();
+        let ops = e.step(vec![d(1, 0.0)], false, DVec3::ZERO);
+        assert_eq!(starts(&ops), 1);
+        let Op::Start(id, v) = &ops[0] else { panic!() };
+        assert_eq!((v.attack, v.loop_from, v.loop_to), (0.3, 0.2, 2.2));
+        for i in 1..10 {
+            let ops = e.step(vec![d(1, f64::from(i))], false, DVec3::ZERO);
+            assert!(matches!(&ops[..], [Op::Update(u, v)] if u == id && v.at.x == f64::from(i)));
+        }
+        // Undeclared for a moment: still sounding; then gone.
+        for _ in 0..GRACE {
+            assert!(e.step(vec![], false, DVec3::ZERO).is_empty());
+        }
+        let ops = e.step(vec![], false, DVec3::ZERO);
+        assert_eq!(ops, vec![Op::Stop(*id)]);
+        assert!(e.is_empty());
+    }
+
+    #[test]
+    fn a_shot_down_engine_coughs_and_dies_and_stays_dead_while_it_falls() {
+        let mut e = Engines::default();
+        e.step(vec![d(1, 0.0)], false, DVec3::ZERO);
+        let mut last = 1.0;
+        let mut stopped_at = None;
+        for t in 1..60 {
+            let mut f = d(1, 0.0);
+            f.damaged = true;
+            let ops = e.step(vec![f], false, DVec3::ZERO);
+            match ops.as_slice() {
+                [Op::Update(_, v)] => {
+                    assert!(v.pitch < last, "the pitch falls");
+                    last = v.pitch;
+                }
+                [Op::Stop(_)] => stopped_at = stopped_at.or(Some(t)),
+                [] => {}
+                o => panic!("{o:?}"),
+            }
+        }
+        assert_eq!(stopped_at, Some(DYING));
+        assert!(last < 0.6);
+        // The wreck is gone, a new drone with the same key sounds again.
+        e.step(vec![], false, DVec3::ZERO);
+        assert_eq!(starts(&e.step(vec![d(1, 0.0)], false, DVec3::ZERO)), 1);
+    }
+
+    #[test]
+    fn a_cut_stops_every_engine_and_starts_them_under_new_ids() {
+        let mut e = Engines::default();
+        let a = e.step(vec![d(1, 0.0), d(2, 5.0)], false, DVec3::ZERO);
+        let ops = e.step(vec![d(1, 100.0), d(2, 105.0)], true, DVec3::ZERO);
+        assert_eq!((stops(&ops), starts(&ops)), (2, 2));
+        let old: Vec<u32> = a.iter().filter_map(|o| if let Op::Start(i, _) = o { Some(*i) } else { None }).collect();
+        for o in &ops {
+            if let Op::Start(i, _) = o {
+                assert!(!old.contains(i), "a new id, so nothing glides across the jump");
+            }
+        }
+    }
+
+    #[test]
+    fn another_sound_for_the_same_entity_restarts_it() {
+        let mut e = Engines::default();
+        e.step(vec![d(1, 0.0)], false, DVec3::ZERO);
+        let mut other = d(1, 0.0);
+        other.event = "airdef:drone.rocket";
+        let ops = e.step(vec![other], false, DVec3::ZERO);
+        assert_eq!((stops(&ops), starts(&ops)), (1, 1));
+    }
+
+    #[test]
+    fn only_the_nearest_are_kept_and_the_same_input_gives_the_same_ops() {
+        let run = || {
+            let mut e = Engines::default();
+            let all: Vec<Decl> = (0..300).map(|i| d(i, f64::from(i) * 3.0)).collect();
+            e.step(all, false, DVec3::ZERO)
+        };
+        let ops = run();
+        assert_eq!(starts(&ops), MAX);
+        assert_eq!(ops, run());
+        let far = ops.iter().filter_map(|o| if let Op::Start(_, v) = o { Some(v.at.x) } else { None }).fold(0.0, f64::max);
+        assert!(far <= (MAX as f64) * 3.0);
+    }
+
+    #[test]
+    fn a_hundred_seek_cycles_leave_no_engine_behind() {
+        let mut e = Engines::default();
+        let mut open = std::collections::BTreeSet::new();
+        for round in 0..100 {
+            let ops = e.step(vec![d(1, round as f64), d(2, 0.0)], round % 3 == 0, DVec3::ZERO);
+            for o in ops {
+                match o {
+                    Op::Start(i, _) => {
+                        open.insert(i);
+                    }
+                    Op::Stop(i) => {
+                        assert!(open.remove(&i), "a stop for a source that was never started");
+                    }
+                    Op::Update(i, _) => assert!(open.contains(&i)),
+                }
+            }
+        }
+        for o in e.step(vec![], true, DVec3::ZERO) {
+            if let Op::Stop(i) = o {
+                open.remove(&i);
+            }
+        }
+        assert!(open.is_empty(), "every start was stopped");
+    }
+}

airdef-mod/src/lib.rs

@@ -13,6 +13,7 @@ use horizon_mod_sdk::{
 };
 
 mod cinema;
+mod engines;
 mod commands;
 mod layout;
 mod film;
@@ -107,6 +108,11 @@ struct AirDef {
     punch: f32,
     /// Sounds on their way to the player at the speed of sound.
     pending: Vec<PendingSound>,
+    /// The engines as persistent sound sources (#95), and the source generation they were started under.
+    engines: engines::Engines,
+    engine_gen: u32,
+    /// Whether the engines are a replay's (a change of mode cuts them).
+    engines_replay: bool,
     /// The handles `render.model-id` gave the model names (valid under `model_generation`); none:
     /// a name the game doesn't know.
     model_ids: std::collections::HashMap<&'static str, Option<u32>>,
@@ -149,6 +155,30 @@ fn switch_allowed(exporting: bool) -> Result<(), String> {
     }
 }
 
+/// An engine voice as a `render.sound-sources` entry.
+fn source_op(kind: render::SourceOpKind, id: u32, v: &engines::Voice) -> render::SourceOp {
+    render::SourceOp {
+        kind,
+        id,
+        event: v.event.to_string(),
+        x: v.at.x,
+        y: v.at.y,
+        z: v.at.z,
+        vx: v.vel.x as f32,
+        vy: v.vel.y as f32,
+        vz: v.vel.z as f32,
+        gain: v.gain,
+        pitch: v.pitch,
+        looping: true,
+        priority: 1.0,
+        attack: v.attack,
+        release: v.release,
+        doppler: engines::DOPPLER,
+        loop_from: v.loop_from,
+        loop_to: v.loop_to,
+    }
+}
+
 /// A sound heard later: when, what, where, and how loud and high it was.
 struct PendingSound {
     due: u64,
@@ -615,7 +645,59 @@ impl AirDef {
         }
     }
 
-    fn emit(&mut self, out: Out) {
+    /// The engines the simulation or the replay declared become persistent sound sources (#95):
+    /// started, followed, stopped. The one-shots below stay as they were.
+    fn step_engines(&mut self, out: &mut Out) {
+        let replay = self.replay.as_ref().is_some_and(|r| r.filming());
+        let cut = std::mem::take(&mut out.engine_cut) || replay != self.engines_replay;
+        self.engines_replay = replay;
+        let generation = render::sound_source_generation();
+        if generation != self.engine_gen {
+            // The game released every source (a world closed, a film began or ended).
+            self.engines.reset();
+            self.engine_gen = generation;
+        }
+        if self.engines.is_empty() && out.engines.is_empty() && !cut {
+            return;
+        }
+        let ops: Vec<render::SourceOp> = self
+            .engines
+            .step(std::mem::take(&mut out.engines), cut, self.listener)
+            .into_iter()
+            .map(|op| match op {
+                engines::Op::Start(id, v) => source_op(render::SourceOpKind::Start, id, &v),
+                engines::Op::Update(id, v) => source_op(render::SourceOpKind::Update, id, &v),
+                engines::Op::Stop(id) => render::SourceOp {
+                    kind: render::SourceOpKind::Stop,
+                    id,
+                    event: String::new(),
+                    x: 0.0,
+                    y: 0.0,
+                    z: 0.0,
+                    vx: 0.0,
+                    vy: 0.0,
+                    vz: 0.0,
+                    gain: 0.0,
+                    pitch: 1.0,
+                    looping: false,
+                    priority: 1.0,
+                    attack: 0.0,
+                    release: 0.0,
+                    doppler: 0.0,
+                    loop_from: 0.0,
+                    loop_to: 0.0,
+                },
+            })
+            .collect();
+        if !ops.is_empty() && !render::sound_sources(generation, &ops) {
+            // Released between the two calls: start them again under the new generation.
+            self.engines.reset();
+            self.engine_gen = u32::MAX;
+        }
+    }
+
+    fn emit(&mut self, mut out: Out) {
+        self.step_engines(&mut out);
         if self.sim.shader {
             render::set_params(&self.shader_params(&out));
         }
@@ -1404,6 +1486,9 @@ impl Mod for AirDef {
             listener: DVec3::ZERO,
             punch: 0.0,
             pending: Vec::new(),
+            engines: engines::Engines::default(),
+            engine_gen: u32::MAX,
+            engines_replay: false,
             model_ids: std::collections::HashMap::new(),
             model_generation: u32::MAX,
             by_id: Vec::new(),
@@ -1547,6 +1632,7 @@ impl Mod for AirDef {
                 out.models.clear();
                 out.particles.clear();
                 out.sounds.clear();
+                out.engines.clear();
                 out.shake = None;
             }
             r.tick(&self.sim, &mut self.ground, self.listener, &mut out);

airdef-mod/src/replay.rs

@@ -68,6 +68,8 @@ pub struct Player {
     fov: f32,
     /// The last tick whose events made their sounds.
     heard: f64,
+    /// The replay time the engines were last declared at (a jump back or far ahead cuts them).
+    engine_t: f64,
     /// Time stands still (Space, or the end reached).
     paused: bool,
     /// The film's own clock in seconds (the replay's moment follows from the plan).
@@ -265,6 +267,7 @@ impl Player {
             look: DVec3::NEG_Z,
             fov: 50.0,
             heard: start,
+            engine_t: -1.0,
             paused: false,
             tau: 0.0,
             wait: false,
@@ -443,6 +446,48 @@ impl Player {
         sim.draw_ghosts(rec, self.t, GHOSTS, out);
         self.direct(rec, ground);
         self.sounds(rec, listener, out);
+        self.engines(rec, listener, false, out);
+    }
+
+    /// The engines as the recording had them at the replay's time, for persistent sound sources
+    /// (#95): every flying drone and lit interceptor, where its track puts it now, moving as the
+    /// track moves, placed round the listener like `sounds`. Taken from the tracks and the replay's
+    /// time, never from the live entities. Silent while time stands still, runs too fast to
+    /// follow, or a title card shows; a seek, a clip change or a new shot cuts them (they start
+    /// afresh), so no sound glides across a jump.
+    fn engines(&mut self, rec: &Recording, listener: DVec3, shot_changed: bool, out: &mut Out) {
+        let moved = self.t - self.engine_t;
+        if self.engine_t < 0.0 || shot_changed || moved < -1e-9 || moved > self.rate * 1.5 + 2.0 {
+            out.engine_cut = true;
+        }
+        self.engine_t = self.t;
+        if self.rate <= 0.0 || self.rate > 4.0 || self.card > 0 {
+            return;
+        }
+        let step = STEP as f64;
+        for (k, tr) in rec.tracks.iter().enumerate() {
+            let Some(p) = tr.at(rec.origin, self.t) else { continue };
+            let ahead = tr.at(rec.origin, self.t + step).unwrap_or(p);
+            let behind = tr.at(rec.origin, self.t - step).unwrap_or(p);
+            // Blocks per tick of the replay: the track's, times how fast the replay runs.
+            let vel = (ahead - behind) / (2.0 * step) * self.rate;
+            let key = 0x8000_0000 | k as u32;
+            let at = listener + (p - self.eye);
+            match tr.what {
+                What::Drone(kind) => {
+                    if let Some((event, pitch)) = kind.engine_voice() {
+                        let falling = tr.fell.is_some_and(|f| self.t >= f as f64);
+                        out.engine(key, event, at, vel, 0.8, pitch, falling);
+                    }
+                }
+                What::Missile(kind, _) => {
+                    if self.t - tr.first as f64 > kind.lit_after() as f64 {
+                        let (event, gain, pitch) = kind.engine_voice();
+                        out.engine(key, event, at, vel, gain, pitch, false);
+                    }
+                }
+            }
+        }
     }
 
     /// Sounds as the camera hears them: moved so the player stands where the camera is.
@@ -512,6 +557,7 @@ impl Player {
         sim.draw_ghosts(rec, self.t, base, out);
         if !self.wait {
             self.sounds(rec, listener, out);
+            self.engines(rec, listener, changed, out);
         } else {
             self.heard = self.t;
         }
@@ -1004,3 +1050,137 @@ mod surface_tests {
         assert_eq!(above_surface(eye, Some(None)), eye);
     }
 }
+
+#[cfg(test)]
+mod engine_tests {
+    use super::*;
+    use crate::engines::{Engines, Op};
+    use crate::sim::{MissileKind, record::Recording};
+
+    fn recording() -> Recording {
+        let mut rec = Recording::blank(2000);
+        // A Shahed flying 1000 blocks east over 1000 ticks, shot down at 600; an interceptor from 400.
+        rec.straight(1, What::Drone(DroneKind::Shahed), 0, 1000, DVec3::new(0.0, 80.0, 0.0), DVec3::new(1000.0, 80.0, 0.0));
+        rec.tracks[0].fell = Some(600);
+        rec.straight(2, What::Missile(MissileKind::Pac3, 0), 400, 700, DVec3::new(0.0, 0.0, 0.0), DVec3::new(600.0, 80.0, 0.0));
+        rec
+    }
+    fn player(rec: &Recording) -> Player {
+        let mut p = Player::new(1, Mode::Full, &Sim::new(1));
+        p.eye = DVec3::new(500.0, 80.0, 30.0);
+        let _ = rec;
+        p
+    }
+    /// A host that remembers which sources run.
+    #[derive(Default)]
+    struct Host(std::collections::BTreeMap<u32, [f64; 3]>);
+    impl Host {
+        fn apply(&mut self, ops: Vec<Op>) {
+            for o in ops {
+                match o {
+                    Op::Start(id, v) => assert!(self.0.insert(id, [v.at.x, v.at.y, v.at.z]).is_none()),
+                    Op::Update(id, v) => assert!(self.0.insert(id, [v.at.x, v.at.y, v.at.z]).is_some()),
+                    Op::Stop(id) => assert!(self.0.remove(&id).is_some()),
+                }
+            }
+        }
+    }
+
+    #[test]
+    fn engines_follow_the_recorded_tracks_at_the_replays_time_around_the_listener() {
+        let rec = recording();
+        let mut p = player(&rec);
+        let listener = DVec3::new(-5.0, 70.0, 12.0);
+        p.t = 450.0;
+        p.rate = 1.0;
+        let mut out = Out::default();
+        p.engines(&rec, listener, false, &mut out);
+        // The first declaration of a replay starts the engines afresh.
+        assert!(out.engine_cut);
+        assert_eq!(out.engines.len(), 2);
+        let drone = out.engines.iter().find(|d| d.key == 0x8000_0000).unwrap();
+        // The drone at tick 450 is at x = 450; the eye stands at x = 500; the player at -5.
+        assert!((drone.at.x - (listener.x + (450.0 - 500.0))).abs() < 1e-6, "{:?}", drone.at);
+        assert!((drone.at.z - (listener.z + (0.0 - 30.0))).abs() < 1e-6);
+        assert!(!drone.damaged && drone.vel.x > 0.0);
+        // The interceptor is lit after its cold launch only.
+        p.t = 401.0;
+        let mut out = Out::default();
+        p.engines(&rec, listener, false, &mut out);
+        assert_eq!(out.engines.iter().filter(|d| d.key == 0x8000_0001).count(), usize::from(401.0 - 400.0 > f64::from(MissileKind::Pac3.lit_after())));
+    }
+
+    #[test]
+    fn pause_seek_and_cut_release_and_restart_engines_without_leaving_any() {
+        let rec = recording();
+        let mut p = player(&rec);
+        let mut engines = Engines::default();
+        let mut host = Host::default();
+        let listener = DVec3::ZERO;
+        let mut tick = |p: &mut Player, engines: &mut Engines, host: &mut Host, shot: bool| {
+            let mut out = Out::default();
+            p.engines(&rec, listener, shot, &mut out);
+            host.apply(engines.step(std::mem::take(&mut out.engines), out.engine_cut, listener));
+        };
+        p.t = 100.0;
+        p.rate = 1.0;
+        for _ in 0..30 {
+            p.t += 1.0;
+            tick(&mut p, &mut engines, &mut host, false);
+        }
+        assert_eq!(host.0.len(), 1, "the drone alone");
+        // Paused: the sources go after their grace.
+        p.rate = 0.0;
+        for _ in 0..6 {
+            tick(&mut p, &mut engines, &mut host, false);
+        }
+        assert!(host.0.is_empty());
+        // Played on again: they start again without a cut.
+        p.rate = 1.0;
+        tick(&mut p, &mut engines, &mut host, false);
+        assert_eq!(host.0.len(), 1);
+        let before: Vec<u32> = host.0.keys().copied().collect();
+        // A seek back and forward, and a hundred shot changes: always one drone, a new source each time.
+        p.t = 50.0;
+        tick(&mut p, &mut engines, &mut host, false);
+        assert_eq!(host.0.len(), 1);
+        assert!(!host.0.contains_key(&before[0]), "the seek restarted the source");
+        p.t = 380.0;
+        tick(&mut p, &mut engines, &mut host, false);
+        for i in 0..100 {
+            p.t = 380.0 + f64::from(i % 7);
+            tick(&mut p, &mut engines, &mut host, i % 3 == 0);
+            assert!(host.0.len() <= 2);
+        }
+        // The drone is shot down at 600: its engine dies away and stays dead while the wreck falls
+        // (the interceptor, flying till 700, is the one source left).
+        p.t = 599.0;
+        tick(&mut p, &mut engines, &mut host, false);
+        let mut silent_after = None;
+        for i in 0..40 {
+            p.t = 600.0 + f64::from(i);
+            tick(&mut p, &mut engines, &mut host, false);
+            if host.0.len() == 1 && silent_after.is_none() {
+                silent_after = Some(i);
+            }
+        }
+        assert!(silent_after.is_some_and(|i| i <= 25), "{silent_after:?}");
+        // The film ends: nothing is left.
+        p.rate = 0.0;
+        for _ in 0..6 {
+            tick(&mut p, &mut engines, &mut host, false);
+        }
+        assert!(host.0.is_empty());
+    }
+
+    #[test]
+    fn a_fast_replay_is_silent() {
+        let rec = recording();
+        let mut p = player(&rec);
+        p.t = 100.0;
+        p.rate = 16.0;
+        let mut out = Out::default();
+        p.engines(&rec, DVec3::ZERO, false, &mut out);
+        assert!(out.engines.is_empty());
+    }
+}

airdef-mod/src/sim/mod.rs

@@ -20,6 +20,7 @@ mod ew;
 pub mod lights;
 mod logistics;
 mod orders;
+mod voices;
 pub mod outcome;
 mod units;
 mod why;
@@ -81,6 +82,10 @@ pub struct Out {
     pub models: Vec<Model>,
     pub particles: Vec<Particle>,
     pub sounds: Vec<(&'static str, DVec3, f32, f32)>,
+    /// The engines sounding this tick (persistent sources, `crate::engines`), and whether the
+    /// picture cut (a replay seek or a new shot): every engine then starts afresh.
+    pub engines: Vec<crate::engines::Decl>,
+    pub engine_cut: bool,
     pub commands: Vec<String>,
     /// Camera jolt (strength, seconds), the strongest this tick.
     pub shake: Option<(f32, f32)>,
@@ -109,6 +114,10 @@ impl Out {
     pub fn sound(&mut self, event: &'static str, at: DVec3, volume: f32, pitch: f32) {
         self.sounds.push((event, at, volume, pitch));
     }
+    /// An engine that sounds: `vel` is the simulation's, blocks a tick.
+    pub fn engine(&mut self, key: u32, event: &'static str, at: DVec3, vel: DVec3, gain: f32, pitch: f32, damaged: bool) {
+        self.engines.push(crate::engines::Decl { key, event, at, vel: vel * 20.0, gain, pitch, damaged });
+    }
     fn jolt(&mut self, strength: f32, seconds: f32) {
         if self.shake.is_none_or(|(s, _)| s < strength) {
             self.shake = Some((strength.min(1.0), seconds));
@@ -1684,6 +1693,9 @@ impl Sim {
                     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 let Some((event, pitch)) = d.kind.engine_voice() {
+                    out.engine(d.id, event, d.pos, d.vel, 0.8, pitch, true);
+                }
                 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) };
@@ -1927,9 +1939,9 @@ impl Sim {
                     out.particles("minecraft:cloud", back - d.vel.normalize_or_zero() * 1.5, 0.15, DVec3::ZERO, 0.005, 1);
                 }
             }
-            let (event, pitch, every) = spec.sound;
-            if d.age % every == 0 {
-                out.sound(event, d.pos, 1.0, pitch);
+            // The engine is one source that follows the drone (#95).
+            if let Some((event, pitch)) = d.kind.engine_voice() {
+                out.engine(d.id, event, d.pos, d.vel, 0.8, pitch, false);
             }
         }
         for (drone, pos) in splits {
@@ -2692,24 +2704,12 @@ impl Sim {
                 done.push((m.id, None, false, m.sam));
                 continue;
             }
-            if lit && spec.flame == 0.0 {
-                if m.age % 20 == 1 {
-                    out.sound("airdef:drone.lancet", m.pos, 0.8, 1.6);
-                }
-            } else if lit {
-                if (m.age - spec.cold) % 46 == 1 {
-                    let pitch = match m.kind {
-                        MissileKind::Pac3 => 1.0,
-                        MissileKind::M57e6 => 1.12,
-                        MissileKind::M48n6 => 0.88,
-                        MissileKind::M77n6 => 0.8,
-                        MissileKind::IrisT | MissileKind::Amraam => 1.05,
-                        MissileKind::M9m317 => 0.9,
-                        MissileKind::M9m338 => 1.15,
-                        MissileKind::P1sun => 1.7,
-                    };
-                    out.sound("airdef:missile.flight", m.pos, 1.0, pitch);
-                }
+            if lit {
+                // The motor is one source that follows the missile from ignition on (#95).
+                let (event, gain, pitch) = m.kind.engine_voice();
+                out.engine(0x4000_0000 | m.id, event, m.pos, m.vel, gain, pitch, false);
+            }
+            if lit && spec.flame > 0.0 {
                 let back = m.pos - new * 1.4 * spec.scale;
                 out.particles("minecraft:flame", back, 0.05, -new * 0.1, 0.01, 2);
                 if m.age % 2 == 0 {

airdef-mod/src/sim/voices.rs

@@ -0,0 +1,40 @@
+//! What the simulation tells the engine sources (`crate::engines`): which sound an entity's
+//! engine makes, from the specs the rest of the simulation owns.
+use super::{DroneKind, MissileKind};
+
+impl DroneKind {
+    /// The sound of its engine and its pitch; none for the ballistic ones, which fall with a
+    /// scream played once (and the Oreshnik's blocks and submunitions, which have no engine).
+    pub fn engine_voice(self) -> Option<(&'static str, f32)> {
+        let spec = self.spec();
+        if spec.ballistic.is_some() || matches!(self, DroneKind::OreshnikBlock | DroneKind::OreshnikSub) {
+            return None;
+        }
+        Some((spec.sound.0, spec.sound.1))
+    }
+}
+
+impl MissileKind {
+    /// The sound of its motor, its gain and its pitch: a rocket's roar, or the electric whine of
+    /// a motor without a flame.
+    pub fn engine_voice(self) -> (&'static str, f32, f32) {
+        if self.spec().flame == 0.0 {
+            return ("airdef:drone.lancet", 0.8, 1.6);
+        }
+        let pitch = match self {
+            MissileKind::Pac3 => 1.0,
+            MissileKind::M57e6 => 1.12,
+            MissileKind::M48n6 => 0.88,
+            MissileKind::M77n6 => 0.8,
+            MissileKind::IrisT | MissileKind::Amraam => 1.05,
+            MissileKind::M9m317 => 0.9,
+            MissileKind::M9m338 => 1.15,
+            MissileKind::P1sun => 1.7,
+        };
+        ("airdef:missile.flight", 1.0, pitch)
+    }
+    /// Ticks from the launch until the motor lights (a cold launch throws it out of the tube first).
+    pub fn lit_after(self) -> u32 {
+        self.spec().cold
+    }
+}

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 01/36] Mod API (AirDef fork): world models, client particles,
+Subject: [PATCH 01/37] 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 02/36] cargo-horizon-mod: report particles and sounds
+Subject: [PATCH 02/37] 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 03/36] Mod API (AirDef fork): full-screen post pass for mods
+Subject: [PATCH 03/37] 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 04/36] Mod models: draw far models as scaled impostors past
+Subject: [PATCH 04/37] 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 05/36] Mod cameras: render.set-views draws the world from
+Subject: [PATCH 05/37] 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 06/36] Mods: more fuel per tick and per event (AirDef plans
+Subject: [PATCH 06/37] 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 07/36] Mod cameras up to 1920x1080 (full-screen replays)
+Subject: [PATCH 07/37] 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 08/36] Mod cameras: distant terrain tiles, fog measured from
+Subject: [PATCH 08/37] 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 09/36] Mods: game.world-id, so mods keep state per world (API
+Subject: [PATCH 09/37] 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 10/36] cargo-horizon-mod: trial runs behind feature full, so a
+Subject: [PATCH 10/37] 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 11/36] HD lighting: G-buffer pass, per-pixel mod point lights
+Subject: [PATCH 11/37] 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 12/36] HD lighting stage 2: sun and moon shadow cascades, the
+Subject: [PATCH 12/37] 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 13/36] HD: bind groups cached until a resize or a new source,
+Subject: [PATCH 13/37] 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 14/36] HD: lights culled per 16x16 tile (surface and halo
+Subject: [PATCH 14/37] 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 15/36] HD: GPU time per pass in the F3 timing list,
+Subject: [PATCH 15/37] 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 16/36] HD: shadows draw only sun-facing quads and skip buried
+Subject: [PATCH 16/37] 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 17/36] Mods: model handles (render.model-id, model-generation,
+Subject: [PATCH 17/37] 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 18/36] HD: temporal upscaling (HORIZON_HD_SCALE: world,
+Subject: [PATCH 18/37] 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 19/36] HD water: its own pass (colour, normal, depth), the
+Subject: [PATCH 19/37] 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 20/36] HD water: no vanilla texture on the surface (the biome
+Subject: [PATCH 20/37] 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 21/36] HD sky and light: a physical atmosphere (Rayleigh, Mie,
+Subject: [PATCH 21/37] 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 22/36] HD water: a darker blue, a little clearer, ripples a
+Subject: [PATCH 22/37] HD water: a darker blue, a little clearer, ripples a
  little higher
 
 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

horizon-patches/0023-HD-Photon-style-sunsets-Rec.-2020-atmosphere-sun-tin.patch

@@ -1,7 +1,7 @@
 From 982265d21bb9d74ec0040db03feb5a55762286ad Mon Sep 17 00:00:00 2001
 From: chexit <chexit@duck.com>
 Date: Thu, 29 Oct 2026 21:41:48 +0300
-Subject: [PATCH 23/36] HD: Photon-style sunsets (Rec. 2020 atmosphere, sun
+Subject: [PATCH 23/37] HD: Photon-style sunsets (Rec. 2020 atmosphere, sun
  tint, blue hour; MIT), volumetric clouds with ground shadows instead of
  vanilla's in HD, volumetric fog with sun shafts and morning mist
  (HORIZON_HD_CLOUDS=0, HORIZON_HD_VOLFOG=0)

horizon-patches/0024-Mods-world-queries-for-simulations-render.query-rays.patch

@@ -1,7 +1,7 @@
 From 24971b3c67d8c87673eb2e0d204cedf8a2f46d1c Mon Sep 17 00:00:00 2001
 From: chexit <chexit@duck.com>
 Date: Thu, 29 Oct 2026 21:43:22 +0300
-Subject: [PATCH 24/36] Mods: world queries for simulations (render.query-rays,
+Subject: [PATCH 24/37] Mods: world queries for simulations (render.query-rays,
  query-sections, world-changes; API level 12): block-exact rays and section
  occupancy by collision, sight or sound, answered next tick within budgets,
  and a log of changed sections

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

@@ -1,7 +1,7 @@
 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 25/36] HD fixes: rain level from the world not from rain
+Subject: [PATCH 25/37] 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

horizon-patches/0026-HD-split-into-modules-gfx-hd-one-Rust-file-and-one-W.patch

@@ -1,7 +1,7 @@
 From 21391afb26f49505d6cdaf454a6355cd4e747503 Mon Sep 17 00:00:00 2001
 From: chexit <chexit@duck.com>
 Date: Thu, 29 Oct 2026 23:19:53 +0300
-Subject: [PATCH 26/36] HD split into modules (gfx/hd/: one Rust file and one
+Subject: [PATCH 26/37] HD split into modules (gfx/hd/: one Rust file and one
  WGSL file per pass, a shared prelude), contracts for colour, depth, alpha,
  time and coordinates written down, tests that the frame layout and bindings
  match between Rust and WGSL (#45)

horizon-patches/0027-HD-clouds-noise-scales-that-divide-the-camera-s-6553.patch

@@ -1,7 +1,7 @@
 From 8d4cadbf8534309ac847d34e229f6d764770475d Mon Sep 17 00:00:00 2001
 From: chexit <chexit@duck.com>
 Date: Thu, 29 Oct 2026 23:22:19 +0300
-Subject: [PATCH 27/36] HD clouds: noise scales that divide the camera's
+Subject: [PATCH 27/37] HD clouds: noise scales that divide the camera's
  65536-block wrap, so the clouds and their shadows no longer jump at x or z =
  0
 

horizon-patches/0028-HD-volumetric-smoke-and-missile-trails-with-clear-tu.patch

@@ -1,7 +1,7 @@
 From 0fb59c782abf269fe555faa3241b31acf41e26d7 Mon Sep 17 00:00:00 2001
 From: chexit <chexit@duck.com>
 Date: Fri, 30 Oct 2026 03:17:11 +0300
-Subject: [PATCH 28/36] HD: volumetric smoke and missile trails with clear
+Subject: [PATCH 28/37] HD: volumetric smoke and missile trails with clear
  tunnels through fog and cloud (render.set-smoke, API level 14; #54); sun
  speculars by material, wet surfaces and puddles in rain, wind in foliage
  (HORIZON_HD_SPECULAR=0, HORIZON_HD_WIND=0, HORIZON_HD_SMOKE=0); HD shaders

horizon-patches/0029-HD-clouds-composited-by-depth-so-terrain-and-vehicle.patch

@@ -1,7 +1,7 @@
 From e4bc29da45d0d38244c6eb2ba3ffb9ab853540c0 Mon Sep 17 00:00:00 2001
 From: chexit <chexit@duck.com>
 Date: Fri, 30 Oct 2026 03:26:09 +0300
-Subject: [PATCH 29/36] HD clouds composited by depth so terrain and vehicles
+Subject: [PATCH 29/37] HD clouds composited by depth so terrain and vehicles
  inside or behind the layer are hidden and those in front stay in front (#67);
  world-anchored noise everywhere (cloud detail by height above the layer, fog,
  smoke and puddle scales dividing the wrap) (#68); the replay's time is visual

horizon-patches/0030-HD-smoke-young-trails-drawn-at-least-as-wide-as-a-gr.patch

@@ -1,7 +1,7 @@
 From 20f699796afb12b600236a4e8859cd97430f86f0 Mon Sep 17 00:00:00 2001
 From: chexit <chexit@duck.com>
 Date: Fri, 30 Oct 2026 03:44:45 +0300
-Subject: [PATCH 30/36] HD smoke: young trails drawn at least as wide as a grid
+Subject: [PATCH 30/37] HD smoke: young trails drawn at least as wide as a grid
  cell (density scaled to keep the mass), gentler bulges, so a trail is a
  smooth ribbon and not a chain of puffs
 

horizon-patches/0031-Mods-render.set-main-view-API-level-15-renders-the-s.patch

@@ -1,7 +1,7 @@
 From 35ffbaa26dd91855c8b93446646ba8c58448d3d0 Mon Sep 17 00:00:00 2001
 From: chexit <chexit@duck.com>
 Date: Fri, 30 Oct 2026 03:59:41 +0300
-Subject: [PATCH 31/36] Mods: render.set-main-view (API level 15) renders the
+Subject: [PATCH 31/37] Mods: render.set-main-view (API level 15) renders the
  screen's world from a mod camera with the full pipeline, so replays get HD
  and the post effects; small mod views get the post pass with their own camera
 

horizon-patches/0032-Spot-lights-for-mods-render.set-spot-lights-API-leve.patch

@@ -1,7 +1,7 @@
 From 27e24527550942695164dd3a769a42a659e797ca Mon Sep 17 00:00:00 2001
 From: chexit <chexit@duck.com>
 Date: Fri, 30 Oct 2026 09:28:05 +0300
-Subject: [PATCH 32/36] Spot lights for mods (render.set-spot-lights, API level
+Subject: [PATCH 32/37] Spot lights for mods (render.set-spot-lights, API level
  16): surfaces lit in the cone, a volumetric beam stopped by depth (#60); film
  capture (render.capture-*, set-film-quality, API level 17): fixed-step clock,
  frames piped to ffmpeg or PNGs, offline audio, no chat in the frames (#58);

horizon-patches/0033-HD-clouds-and-fog-polish-cloud-panorama-cirrus-terra.patch

@@ -1,7 +1,7 @@
 From 615f5c3fa7c19a9895f8972a88333c6f250ad78a Mon Sep 17 00:00:00 2001
 From: chexit <chexit@duck.com>
 Date: Fri, 30 Oct 2026 14:30:39 +0300
-Subject: [PATCH 33/36] HD clouds and fog polish: cloud panorama, cirrus,
+Subject: [PATCH 33/37] HD clouds and fog polish: cloud panorama, cirrus,
  terrain-aware fog, far smoke cascade; replay world log and film clock;
  material overlays by sprite name
 

horizon-patches/0034-HD-coloured-sun-through-glass-and-leaves-rain-ripple.patch

@@ -1,7 +1,7 @@
 From 0254984fdcce53a4a0f2bff15f9be3b78c93842e Mon Sep 17 00:00:00 2001
 From: chexit <chexit@duck.com>
 Date: Fri, 30 Oct 2026 15:01:09 +0300
-Subject: [PATCH 34/36] HD: coloured sun through glass and leaves, rain ripples
+Subject: [PATCH 34/37] HD: coloured sun through glass and leaves, rain ripples
  on water, film motion blur and depth of field
 
 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

horizon-patches/0035-Film-export-every-frame-in-flight-reaches-the-writer.patch

@@ -1,7 +1,7 @@
 From 9645d3f1f47d8bb358d5630288bdd801bd874911 Mon Sep 17 00:00:00 2001
 From: chexit <chexit@duck.com>
 Date: Fri, 30 Oct 2026 15:19:32 +0300
-Subject: [PATCH 35/36] Film export: every frame in flight reaches the writer,
+Subject: [PATCH 35/37] Film export: every frame in flight reaches the writer,
  listener follows the main view, cloud wind on film frames, set-smoke reports
  real activity
 

horizon-patches/0036-Mod-command-trees-command.set-tree-and-set-suggestio.patch

@@ -1,7 +1,7 @@
 From 22d6835507d5627b0fe4a749b082b025b35e0262 Mon Sep 17 00:00:00 2001
 From: chexit <chexit@duck.com>
 Date: Fri, 30 Oct 2026 15:43:11 +0300
-Subject: [PATCH 36/36] Mod command trees: command.set-tree and
+Subject: [PATCH 36/37] Mod command trees: command.set-tree and
  set-suggestions, typed parse, colouring and completion from one tree (API 19)
 
 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>