A server sends an item's and a falling block's position only every 20 ticks.
As a client (multiplayer, a LAN guest, single player on its server thread)
Horizon moved them only when a position arrived, three steps towards it, so a
dropped item or falling sand hung in the air and then jumped down once a
second (#1568).
Vanilla runs ItemEntity.tick and FallingBlockEntity.tick on the client too
(gravity, collisions, drag), takes their motion from AddEntity
(recreateFromPacket) and SetEntityMotion (Entity.lerpMotion), and snaps them to
each position packet: neither overrides Entity's NO_OP InterpolationHandler.
The client now does the same, with the same ticks single player in-frame uses;
only the server removes them or places the block.
lan_e2e --check falling: the guest samples both every 2 ticks over 16 ticks.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
The game logs into HORIZON_HOME and falls back to the player's own game folder when it is unset. Harnesses
that set only HORIZON_NO_AUDIO (and test_native_client, which set nothing) wrote logs, and on a world run
advancements, into ~/Library/Application Support/horizon.
lab.game_env gives every game a fresh HORIZON_HOME, HORIZON_LAUNCHER_HOME, XDG_DATA_HOME and XDG_CONFIG_HOME,
no audio and no launcher self-update; a folder the caller passes is kept. Every launcher of the game uses it,
parity.py gives each harness its own HORIZON_HOME, and tests/test_game_home.py fails for a script in tools/
that starts the game without it.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Walking through the cart pushes it back once past its middle, so the
check stands the player half into the cart from the north and waits.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
lan_e2e's vehicles check: a creative break whose block is put back stays,
a player stands on a boat, lava breaks a ridden boat and lets the rider
out, a minecart in lava breaks and a TNT one goes off, and walking into a
minecart pushes it, for the host and the guest.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
A guest's (and, on the server thread, the window's) knockback started from
the velocity the last hit left on its server copy, which nothing ever
slowed down, and each hit went out at once. So every hit after the first
pushed harder (0.72, then 0.76 blocks a tick where vanilla sends 0.4 each
time), netherite resisted from the wrong base, and a zombie's hit reached
the client before the friction of the tick it landed in.
Vanilla's server simulates a player too (MoveSimulationType
AUTHORITATIVE_SIDE_AND_SERVER): ServerPlayer travels every tick with no
input, and ServerEntity.sendChanges sends a velocity a hurt marked
(Entity.markHurt) as it is after that travel. A player's melee hit is the
exception (Player.causeExtraKnockback): it sends at once, then puts the
server copy back to its velocity from before the hit.
- MotionWorld::server_travel: Player.travel with no input, keeping only
the velocity (the client's moves place the player). The server's copy
checks no fall damage on its own moves (isLocalInstanceAuthoritative).
- guest_server_tick runs it last, then sends the velocity if a hurt
marked it since the last tick.
- guest_hit_by leaves a marked velocity to that; guest_struck_by (melee
from a player) sends at once and restores.
- lan_e2e `knockback`: three hits each way push the victim as far each
time.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
🤖 Agent: merged after verify and CI parity passed, built merged with current main (discord-gate-1: player reports checked against vanilla 26.3; a lan_e2e check fails on main and passes here in both modes; evidence in the PR body).
InteractWithDoor was a stub, so a villager whose path went through a
closed oak door walked into it and stayed there. In generated villages,
villagers who were inside a house never reached a job site, a bed or
the meeting point.
Like vanilla, a villager now opens the closed mob-interactable doors on
its next path step (DoorBlock.setOpen: both halves, the door sound and
the block_open game event), remembers the door it leaves and the doors
it opened, and closes them once it is more than one step past them,
unless another villager within 2 blocks is walking through. A villager
going to sleep closes them too.
The mob events apply after the mob loop, so the door opens one tick
later than in vanilla, where DoorBlock.setOpen changes the world during
the villager's brain tick.
lan_e2e's new doors check shuts a villager in a room with a closed
door and a free composter outside. Before, it never opened the door;
now it opens it, becomes a farmer, and the door is closed again on the
server and on the guest.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
🤖 Agent: merged after verify and CI parity passed, built merged with current main (st-default-1: server-thread gaps checked against vanilla, each with a lan_e2e check that fails on main and passes here, host and guest, both modes; tables in the PR body).
🤖 Agent: merged after verify and CI parity passed, built merged with current main (st-default-1: server-thread gaps checked against vanilla, each with a lan_e2e check that fails on main and passes here, host and guest, both modes; tables in the PR body).
🤖 Agent: merged after verify and CI parity passed, built merged with current main (st-default-1: server-thread gaps checked against vanilla, each with a lan_e2e check that fails on main and passes here, host and guest, both modes; tables in the PR body).
🤖 Agent: merged after verify and CI parity passed, built merged with current main (st-default-1: server-thread gaps checked against vanilla, each with a lan_e2e check that fails on main and passes here, host and guest, both modes; tables in the PR body).
🤖 Agent: merged after verify and CI parity passed, built merged with current main (st-default-1: server-thread gaps checked against vanilla, each with a lan_e2e check that fails on main and passes here, host and guest, both modes; tables in the PR body).
ServerPlayerGameMode breaks a digging player's block only when the
player's client says it is done (STOP_DESTROY_BLOCK, or the delayed
destroy), or at once when it is instant. The host ran the guest's
tick_mining with its own count and broke the block when that reached 1.
A guest whose client ran even a tick behind lost the block before it
predicted the break: no destroy particles, no break sound, and the
dropped item could appear before the block vanished.
lan_e2e's new digging check holds attack across six oak logs and hears
six breaks, then stalls the guest for a second halfway through stone:
the stone is still there on both sides when it resumes.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
🤖 Agent: merged after verify and CI parity passed, built merged with current main (st2: entity use with either hand and server chat components; lan_e2e checks pass in both modes. The hands check's only flake was a vanilla crit arrow killing the cow, fixed in c89695dd9: 40 of 40 runs pass).
AbstractContainerMenu.removed hands the stack a closing player holds on the
cursor to placeItemBackInInventory (dropped only what doesn't fit, or for a
player who left), and broadcastChanges then empties the client's cursor. The
LAN host threw it out at the player's eyes instead, for the inventory and
every container, crafting, station, mount and merchant menu, and the client
kept showing a copy on its cursor (#1283).
The three ContainerClose arms now place it back through lan_place_back and
send the inventory, carried stack included.
tools/lan_e2e.py gains a cursor check: each player picks up a stack in their
inventory and closes it.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Lightning (Entity.thunderHit) and evoker fangs (EvokerFangs.dealDamageTo) hit
every entity in their box, but thunder_hit and fangs_bite only looked at the
window's own player, so a server's players (guests, and single player on the
server thread) were never struck (#1480, #1481). Both now run their player
part for each guest too, through Game::each_guest_hit.
The effects a mob gives the player it acts on (cave spider and bee poison, husk
hunger, wither skeleton wither, the nautilus's breath) and an axolotl's help
after a kill stayed with the server's own player: acts_on_player now routes
MobEvent::EffectPlayer and MobEvent::AxolotlSupportPlayer to the guest the mob
sees, like its blows (#1484, #1485).
tools/lan_e2e.py gains a strikes check: a bolt hurts each player standing in
water, and a cave spider poisons them.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
On a server (guests, and single player on the server thread) the window ticks
its player through tick_remote_level, which copied the yaw, the Respiration
level, the wings and FAST_LAVA but not the rest of what the in-frame tick sets
from the window's own state. Both now call Game::sync_player_body:
- the look pitch: Player.travel steers sprint-swimming up and down by it (#1303)
- the slowdown of an item in use, LocalPlayer.modifyInput (#1278)
- leather boots, PowderSnowBlock.canEntityWalkOnPowderSnow (#1296)
- freeze-immune wear, LivingEntity.canFreeze
- the Auto Jump option, LocalPlayer.sendPosition (#1279)
tools/lan_e2e.py gains a body check: each player walks while drawing a bow,
stands on powder snow with leather boots and without, and sprint-swims looking
down.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
A map a server's player (a LAN guest, or single player's window on its
server thread) made stayed blank and saved nothing (#1382): only the
game's own player ever updated a map, and no map data went to the guests.
Each guest's turn now runs MapItem's ticks as theirs (the marker of every
carried map, the reveal of the held ones), and the server sends each guest
ClientboundMapItemDataPacket for the maps it carries, and every 10 ticks
for the maps framed in the level (ServerPlayer.synchronizeSpecialItemUpdates,
ServerEntity.sendChanges).
As in vanilla, a map keeps its holders (MapItemSavedData.HoldingPlayer):
each has its own column sweep and its own record of what changed since its
last packet, so the packet carries only the changed pixels' box, and the
decorations at most every 5th tick while they changed. Player markers are
kept per holder, so each player's marker shows on a shared map, and go
when that player stops carrying it. A server's client now applies the
packet's decorations.
lan_e2e maps: host and guest each make and hold a map, which draws the
terrain around them and their marker, in both modes.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
A server's players (LAN guests, and single player's window on its server
thread) cast no lasting hook and caught nothing (#1348): the guest's cast
went into the game's own hook, which the server's tick then dropped for
want of a local player. Each guest now keeps its own hook (Player.fishing),
swapped in with the rest of its state for its turns, ticked as theirs every
server tick, and dropped when they die. Reeling in retrieves it on the
server: a catch, the rod's wear, the experience.
The server tracks every hook to its players as a fishing_bobber entity
(FishingHook.getAddEntityPacket: the owner's id; DATA_HOOKED_ENTITY and
DATA_BITING). A client takes the one its own player cast as its hook, so
the rod shows cast and the line runs to its hand, and draws the others'
bobbers on lines to their owners' hands.
A hook resting on a block stays on the ground (Entity.move keeps onGround
when nothing moves vertically); it used to flip every tick, so reeling it
in cost the rod 2 only half the time.
lan_e2e fishing: host and guest, both modes: the hook stays out and both
sides draw it, reeling in from the ground costs 2, and in open water with
Lure III a fish bites and is caught for 1.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
🤖 Agent: merged after verify and CI parity passed, built merged with current main (st-default-1: server-thread gaps checked against vanilla, each with a lan_e2e check that fails on main and passes here, host and guest, both modes; tables in the PR body).
A wind charge's burst (ServerExplosion with TRIGGER_BLOCK) pushed only the
game's own player, so a LAN guest, and single player's window on its server
thread, never rose (#1386). The burst now pushes every player in reach, each
swapped in as the player, and sends ClientboundExplodePacket to the players
within 64 blocks with the push it gave them (hitPlayers), which their client
adds (Entity.pushFromExplosion); onExplosionHit's fall-damage grace goes on
the server's body. A burst from a guest's own turn (their charge landing,
their mace's wind burst) waits for the turn to end, so that it reaches the
host and the other guests too.
The packet's centre particle is the gust emitter and it throws no block
particles, as WindCharge.explode asks; the client now draws the packet's
own particle. Explosion knockback resistance lowers the player's push as in
vanilla, and a guest's body knows whether it flies (no push while flying in
creative).
lan_e2e wind: host and guest each throw a charge at their feet, rise about
six blocks and land unhurt, in both modes.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
A fully drawn bow fires a crit arrow: AbstractArrow.onHitEntity adds
random.nextInt(damage / 2 + 2) to the 6 damage, so one shot in five does 10
and kills the 10 health cow. The off hand bucket then had nothing to milk
("the host's off hand holds minecraft:bucket"), on either side, in any mode.
Under 20 ticks of draw the arrow is no crit and does at most 6. The check
now also asserts the cow is still there after the shot.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Item.use runs on the client as well (MultiPlayerGameMode.useItem), and
only a use the client started sends RELEASE_USE_ITEM when the button
lets go. A server's client started one for bows and food only, so a
shield kept blocking after release, a charged trident never left the
hand, a loaded crossbow stayed "in use" on the server and never fired,
and a spyglass never scoped. The client now starts what the window's
own Item.use does: a bow or crossbow with ammunition, a trident, a
spyglass, a shield off cooldown, and keeps it until the button lets go.
The server's RELEASE_USE_ITEM let go of a main-hand bow only. It now
runs ServerPlayer.releaseUsingItem with the used item's hand, through
the release the window's own tick shares (bow, trident, spyglass).
A loaded crossbow reached its client without its ammunition: the
network stack gets minecraft:charged_projectiles (registry id 51,
ItemStackTemplate list), and a server's client decodes it.
lan_e2e gets a helduse check, for the host and the guest, both modes.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
A server's client never took the chest slot's Elytra into its own
movement (player.glider) and never told the server it started gliding,
so on the server thread and as a LAN guest the player just fell. The
client now sets the glider as the window's own tick does and sends
ServerboundPlayerCommandPacket START_FALL_FLYING when a glide starts.
The hub used to accept that command blindly and never clear it. The game
now answers it as handlePlayerCommand does (Player.tryToStartFallFlying,
else stopFallFlying), and each tick runs LivingEntity.updateFallFlying
for a gliding guest: the glide ends once canGlide fails (landed, riding,
flying, levitation, a glider about to break), every 20th tick wears the
Elytra, every 10th is an elytra_glide game event, and a glide that isn't
diving keeps the fall distance at 1 (checkFallDistanceAccumulation).
lan_e2e gets an elytra check, for the host and the guest, both modes.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
A server's player (a LAN guest, or single player's window on its server
thread) could neither write in a book and quill nor read a written book:
the server opened the screens in the guest's turn and dropped them (#1366).
As in vanilla, the client opens a book and quill's editor itself when it
uses one (LocalPlayer.openItemGui) and sends ServerboundEditBookPacket
when it saves or signs; the server writes the pages or makes the written
book, signed with the player's name, in that hotbar slot or the off hand.
A written book opens on the client when the server sends
ClientboundOpenBookPacket for its hand (ServerPlayer.openItemGui).
horizon-protocol: OpenBook and EditBook (pages a list of at most 100).
horizon-ctl: book sign presses Sign, then Sign and Close; book done on a
book and quill saves it, as its Done button does.
lan_e2e books: host and guest each write, sign, read and drop a book,
both modes.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
A sign a server's player placed (a LAN guest, or single player's window on
its server thread) opened no editor: its turn's editor was dropped with
the rest of the guest's screens (#1380). The server now does as
ServerPlayer.openTextEdit: the block, then ClientboundOpenSignEditorPacket,
and the player may write on that sign. The client opens its editor on the
sign it has and sends ServerboundSignUpdatePacket when it closes; the
server takes the lines (formatting codes stripped) unless the sign is
waxed, the player was not the one allowed or went out of reach, and sends
the sign to everyone. The window's own sign now reaches its guests too
(sendBlockUpdated, not only a save).
horizon-protocol: OpenSignEditor and SignUpdate, with SignTextSlot as a
VarInt and the lines as a fixed list of four (26.3's stream codecs).
horizon-ctl: type and key reach an open sign editor; block shows a sign's
lines.
lan_e2e signs: host and guest each place, write and see, both modes.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
The guest death path (LAN guests, dedicated players and single player's
window on its server thread) gave the experience reward but never ran
Player.dropEquipment, so a player died with keep_inventory off and kept
everything (#1284). Both paths now share one drop_inventory:
destroyVanishingCursedItems, then Inventory.dropAll from the eyes less 0.3.
ServerPlayer.die skips the loot for spectators only; the window's own
death skipped it in creative too, which vanilla doesn't.
lan_e2e keepinv: host and guest, keep_inventory off and on, both modes.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
A server's players (LAN guests, and single player's window on its server
thread) never had a totem ready, and nothing applied one: lethal damage
killed them with the totem still in hand (#1292). Each guest turn now
readies the totem from the guest's hands and, when its hurt set it off,
uses it up at the end of the turn (LivingEntity.checkTotemDeathProtection):
1 health, the item_used stat, the used_totem trigger, the use vibration,
the totem's effects.
Entity event 35 now goes to every client around, the holder's own too,
and a client plays it as ClientPacketListener.handleEntityEvent does: the
totem particles, the sound heard locally (not sent on as a sound packet,
so no client hears it twice) and the holder's rumble.
lan_e2e totem: host and guest, off hand and main hand, both modes.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Ludovic Marie