Merge pull request #5800 from 1038april/feat/ram-limit-game

🤖 Agent: Review by Ludovic's AI agent (Claude). Opt-in RAM limit; off, it costs one atomic store per frame. kacpherek's grace-period point is fixed and tested. I merged main again (ram_limit next to random_textures, render_distance_in_use next to the leaf-culling remesh). Verify green on this head.

.github/workflows/mojang-republish.yml

@@ -0,0 +1,31 @@
+name: mojang republish
+# Hourly: does Mojang's version manifest list a pinned-version JSON that research-lock.json does not know?
+# If so, one issue "Mojang republished <version>: <sha8>" with the hashes and a lock snippet
+# (tools/ci/mojang_republish.py). Reads only Mojang's public manifest.
+#   gh workflow run "mojang republish" -f dry_run=true
+on:
+  schedule:
+    - cron: '23 * * * *'  # hourly: a republished JSON breaks horizon-prepare for every new player until accepted
+  workflow_dispatch:
+    inputs:
+      dry_run:
+        description: Only print what it would do with issues
+        type: boolean
+        default: false
+permissions:
+  contents: read
+  issues: write
+concurrency:
+  group: mojang-republish
+  cancel-in-progress: false
+
+jobs:
+  check:
+    runs-on: ubuntu-latest
+    timeout-minutes: 10
+    steps:
+      - uses: actions/checkout@v4
+      - name: Check the manifest
+        env:
+          GH_TOKEN: ${{ github.token }}
+        run: python3 tools/ci/mojang_republish.py ${{ inputs.dry_run && '--dry-run' || '' }}

AGENTS.md

@@ -56,6 +56,7 @@ Game workspace (root `Cargo.toml`); `launcher/` and `crates/horizon-telemetry-se
 | `horizon-friends`, `horizon-relay` | Play with Friends: invite codes, encrypted tunnel, the relay ([docs/play-with-friends.md](docs/play-with-friends.md)) |
 | `horizon-mods`, `cargo-horizon-mod` | Content mods (`.hmod`: manifest, content fence, no code), the registry index and `.hpack`, and `cargo horizon-mod` (`new`, `build`, `run`, `check`, `registry`) ([docs/mods.md](docs/mods.md)). Code mods are native, built by the launcher ([docs/native-mods.md](docs/native-mods.md)) |
 | `horizon-port-pack` | Porting Java modpacks ([docs/modpacks.md](docs/modpacks.md)) |
+| `horizon-optifine` | OptiFine-format pack files below every feature that reads them: `.properties`, the name/range/block matchers, paths and `optifine/` folders, and custom entity models (`cem/`: `.jem`/`.jpm` parsing and baking) |
 | `horizon-shader-api` | Horizon's own WGSL shader packs ([docs/api/shaders.md](docs/api/shaders.md)): `horizon-shaders.toml`, the `.hshader` package; shared by the game, the launcher and the registry |
 | `horizon-shaders` | Shader packs (the `shaders/` folder format), rebuilt clean-room from a written spec of the format; no wgpu |
 | `horizon-theme` | Design tokens and fonts for the launcher, the game's own menus and the website |

Cargo.lock

@@ -1323,6 +1323,7 @@ dependencies = [
  "horizon-items",
  "horizon-mods",
  "horizon-narrator",
+ "horizon-optifine",
  "horizon-protocol",
  "horizon-server-files",
  "horizon-shader-api",
@@ -1394,6 +1395,7 @@ dependencies = [
  "horizon-hdr",
  "horizon-items",
  "horizon-narrator",
+ "horizon-optifine",
  "horizon-protocol",
  "horizon-shader-api",
  "horizon-shaders",
@@ -1478,6 +1480,7 @@ dependencies = [
  "horizon-client-core",
  "horizon-core",
  "horizon-world",
+ "log",
  "serde",
  "serde_json",
 ]
@@ -1513,6 +1516,8 @@ dependencies = [
 name = "horizon-optifine"
 version = "0.1.0"
 dependencies = [
+ "horizon-bench",
+ "log",
  "regex",
 ]
 

THIRD_PARTY_NOTICES.md

@@ -66,3 +66,28 @@ with Microsoft accounts
 The four-square Microsoft symbol in `launcher/src/microsoft.rs` reproduces the squares, positions and
 colours of Microsoft's official `ms-symbollockup_mssymbol_19.svg` from that page, unmodified. Microsoft
 and its logo are trademarks of the Microsoft group of companies; Horizon is not endorsed by Microsoft.
+
+## CIT Resewn
+
+`crates/horizon-optifine/src/cit.rs` and `crates/horizon-client-render/src/cit.rs` follow the
+condition semantics of [CIT Resewn Continuation](https://github.com/EthanVisagie/CIT-Resewn-Continuation-1.21.11)
+(at `b792f9a`), a continuation of [CIT Resewn](https://github.com/SHsuperCM/CITResewn) by SHsuperCM: the
+1.21 component paths, enchantment levels, percent damage, text matching and rule ordering. It is
+licensed under the MIT license:
+
+> Copyright (c) 2021 SHsuperCM
+>
+> Permission is hereby granted, free of charge, to any person obtaining a copy of this software
+> and associated documentation files (the "Software"), to deal in the Software without
+> restriction, including without limitation the rights to use, copy, modify, merge, publish,
+> distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the
+> Software is furnished to do so, subject to the following conditions:
+>
+> The above copyright notice and this permission notice shall be included in all copies or
+> substantial portions of the Software.
+>
+> THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
+> BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+> NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+> DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+> OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

crates/cargo-horizon-mod/template/content/horizon-mod.toml

@@ -6,5 +6,5 @@ authors = []
 # A content mod: blocks, items and mob effects from data/ and assets/, no code (API 0.2).
 api = "0.2"
 side = "both"
-# registries: "May add blocks, items and mob effects to your worlds".
+# registries: "May add blocks, items, mob effects and entity types to your worlds".
 capabilities = ["registries"]

crates/horizon-anticheat/src/lib.rs

@@ -281,6 +281,13 @@ pub struct Player {
     pub ground: Option<(u64, f64)>,
     /// The client ticks the prediction plays again (only while it runs).
     pub record: Option<Box<prediction::Record>>,
+    /// Sprinting as the client's own commands left it (ServerboundPlayerCommandPacket's
+    /// START_SPRINTING and STOP_SPRINTING: LocalPlayer.wasSprinting), which the record's ticks take.
+    /// Not the server's player: a hit with extra knockback stops its sprint
+    /// (Player.causeExtraKnockback), the client's own `Player.attack` doesn't (a mob's `hurtClient`
+    /// is false), and once the server's flag reaches it LocalPlayer.aiStep starts the sprint again
+    /// while the sprint key is held, with nothing to say: wasSprinting never changed.
+    pub sprinting: bool,
     /// The attacks of the client tick being heard.
     pub attacks: combat::Attacks,
 }

crates/horizon-anticheat/src/prediction.rs

@@ -39,6 +39,11 @@ pub enum Change {
     /// movement speed (the client takes the modifiers as sent, so a sprint modifier the packet
     /// lacks is gone while the client sprints), None when it didn't (the client keeps its own).
     Attributes { sprint: Option<bool> },
+    /// ClientboundSetEntityDataPacket for the player itself with its shared flags: their sprinting
+    /// bit, which the client takes as sent (SynchedEntityData.assignValues sets the flag alone, its
+    /// speed modifier and wasSprinting stay). A client whose sprint the server cleared this way
+    /// starts it again in its next aiStep, which adds the modifier back, and says nothing.
+    Sprinting(bool),
     /// ClientboundUpdateMobEffectPacket or ClientboundRemoveMobEffectPacket for the player itself:
     /// the server's effects, as they are when the replay reaches it. (Their attribute modifiers
     /// are the server's: they reach the client as attributes.)

crates/horizon-client-render/Cargo.toml

@@ -17,6 +17,9 @@ horizon-hdr = { path = "../horizon-hdr" }
 horizon-items = { path = "../horizon-items" }
 # The narrator option's status and whether the narrator is there (Options.narrator).
 horizon-narrator = { path = "../horizon-narrator" }
+# OptiFine-format pack files: random entity textures (hud.rs), connected textures
+# (connected.rs) and custom item texture rules (cit.rs).
+horizon-optifine = { path = "../horizon-optifine" }
 horizon-protocol = { path = "../horizon-protocol" }
 horizon-shader-api = { path = "../horizon-shader-api" }
 horizon-shaders = { path = "../horizon-shaders" }

crates/horizon-client-render/src/assets.rs

@@ -101,6 +101,8 @@ pub struct RenderAssets {
     pub pbr_normals: Vec<u8>,
     pub pbr_specular: Vec<u8>,
     pub pbr_size: u32,
+    /// OptiFine connected textures (empty without `optifine/ctm` files).
+    pub connected: crate::connected::ConnectedTextures,
 }
 fn invalid(message: &str) -> io::Error {
     io::Error::new(io::ErrorKind::InvalidData, message)
@@ -240,9 +242,34 @@ impl RenderAssets {
         for stage in 0..10 {
             sprites.insert(root, &format!("minecraft:block/destroy_stage_{stage}"))?;
         }
-        if draws {
+        let connected = if draws {
             crate::native_emissive::load(root, &mut sprites);
-        }
+            // A side's sprite, for rules that connect by tile: the first quad facing it.
+            let catalog = &models.catalog;
+            let mut found = Vec::new();
+            crate::connected::ConnectedTextures::load(
+                root,
+                registry,
+                &mut sprites,
+                |state, face| {
+                    let side = horizon_assets::model::Direction::ALL[face as usize];
+                    catalog
+                        .models_at(
+                            state,
+                            horizon_core::position::BlockPos::new(0, 0, 0),
+                            &mut found,
+                        )
+                        .ok()?;
+                    found
+                        .iter()
+                        .flat_map(|m| &m.faces)
+                        .find(|f| f.quad.facing == side)
+                        .map(|f| f.layer)
+                },
+            )
+        } else {
+            Default::default()
+        };
         sprites.save_disk_cache();
         if draws {
             sprites.finish();
@@ -267,6 +294,7 @@ impl RenderAssets {
             pbr_normals: sprites.normals,
             pbr_specular: sprites.specular,
             pbr_size: sprites.pbr_size,
+            connected,
         })
     }
 }

crates/horizon-client-render/src/audio.rs

@@ -1179,6 +1179,15 @@ impl Audio {
         self.sync_volumes();
         self.engine.tick(paused, ctx, &mut self.backend);
     }
+    /// The `uiSoundReserve` extra: positional sounds leave
+    /// `sound_engine::HEARD_RESERVE` static channels free (off: vanilla's pool).
+    pub fn set_listener_reserve(&mut self, on: bool) {
+        self.engine.listener_reserve = if on {
+            crate::sound_engine::HEARD_RESERVE
+        } else {
+            0
+        };
+    }
     /// `SoundManager.pauseAllExcept(MUSIC, UI)`.
     pub fn pause(&mut self) {
         self.engine.pause_all_except(

crates/horizon-client-render/src/biome.rs

@@ -387,6 +387,52 @@ impl Biomes {
     }
 }
 
+/// A biome's colours as a mod may change them (`native_biome_colors`), each
+/// 0xRRGGBB: what tints grass (before the dark forest's modifier; the swamp's
+/// noise colours replace it), leaves and vines, dry foliage (leaf litter) and
+/// water.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub struct BiomeColors {
+    pub grass: u32,
+    pub foliage: u32,
+    pub dry_foliage: u32,
+    pub water: u32,
+}
+
+impl Biomes {
+    /// This table with each biome's colours passed through `f`, given the
+    /// biome's name (`minecraft:plains`) and its colours; None when `f`
+    /// changed none. Bits past 0xFFFFFF are dropped.
+    pub fn with_colors(&self, mut f: impl FnMut(&str, &mut BiomeColors)) -> Option<Self> {
+        let mut out = self.clone();
+        let mut changed = false;
+        for b in &mut out.list {
+            let before = BiomeColors {
+                grass: b.grass,
+                foliage: b.foliage,
+                dry_foliage: b.dry_foliage,
+                water: b.water,
+            };
+            let mut colors = before;
+            f(&b.name, &mut colors);
+            let after = BiomeColors {
+                grass: colors.grass & 0xFF_FFFF,
+                foliage: colors.foliage & 0xFF_FFFF,
+                dry_foliage: colors.dry_foliage & 0xFF_FFFF,
+                water: colors.water & 0xFF_FFFF,
+            };
+            if after != before {
+                changed = true;
+                b.grass = after.grass;
+                b.foliage = after.foliage;
+                b.dry_foliage = after.dry_foliage;
+                b.water = after.water;
+            }
+        }
+        changed.then_some(out)
+    }
+}
+
 /// A 24-bit colour as sRGB components in 0..1.
 pub fn rgb(c: u32) -> [f32; 3] {
     [16, 8, 0].map(|shift| (c >> shift & 255) as f32 / 255.0)
@@ -534,6 +580,81 @@ mod pack_tests {
     }
 }
 
+#[cfg(test)]
+mod color_tests {
+    use super::*;
+    use serde_json::json;
+
+    fn biomes() -> Biomes {
+        let maps = Colormaps {
+            grass: Vec::new(),
+            foliage: Vec::new(),
+            dry: Vec::new(),
+        };
+        let effects = |grass: u32, modifier: &str| {
+            json!({"effects": {"grass_color": grass, "foliage_color": 0x112233,
+                "dry_foliage_color": 0x445566, "water_color": 0x3F76E4,
+                "grass_color_modifier": modifier}})
+        };
+        let list = vec![
+            BiomeInfo::from_json("minecraft:plains".into(), &effects(0x91BD59, "none"), &maps),
+            BiomeInfo::from_json(
+                "minecraft:dark_forest".into(),
+                &effects(0x91BD59, "dark_forest"),
+                &maps,
+            ),
+        ];
+        Biomes {
+            builtin: Arc::new(list.clone()),
+            index: list
+                .iter()
+                .enumerate()
+                .map(|(i, b)| (b.name.clone(), i as u16))
+                .collect(),
+            list,
+            info_noise: SimplexNoise::with_skipped_offsets(&mut LegacyRandom::new(2345), true),
+            colormaps: Arc::new(maps),
+            packs: BTreeMap::new(),
+        }
+    }
+
+    #[test]
+    fn a_change_reaches_the_tints_the_mesher_reads() {
+        let autumn = biomes()
+            .with_colors(|name, c| {
+                c.foliage = 0xD2691E;
+                if name == "minecraft:plains" {
+                    c.grass = 0xBFA055;
+                }
+            })
+            .expect("changed");
+        let plains = autumn.id("minecraft:plains");
+        assert_eq!(autumn.grass(plains, 0.0, 0.0), 0xBFA055);
+        assert_eq!(autumn.get(plains).foliage, 0xD2691E);
+        assert_eq!(autumn.get(plains).dry_foliage, 0x445566);
+        assert_eq!(autumn.get(plains).water, 0x3F76E4);
+        // The dark forest's modifier still darkens its (unchanged) grass:
+        // ((0x91BD59 & 0xFEFEFE) + 0x28340A) >> 1.
+        let dark = autumn.id("minecraft:dark_forest");
+        assert_eq!(autumn.grass(dark, 0.0, 0.0), 0x5C7831);
+        assert_eq!(autumn.get(dark).foliage, 0xD2691E);
+    }
+
+    #[test]
+    fn no_change_gives_none_and_alpha_bits_are_dropped() {
+        assert!(biomes().with_colors(|_, _| {}).is_none());
+        assert!(
+            biomes()
+                .with_colors(|_, c| c.water |= 0xFF00_0000)
+                .is_none()
+        );
+        let blue = biomes()
+            .with_colors(|_, c| c.water = 0xFF00_00FF)
+            .expect("changed");
+        assert_eq!(blue.get(0).water, 0x0000FF);
+    }
+}
+
 #[cfg(test)]
 mod blend_tests {
     use super::*;

crates/horizon-client-render/src/brewing.rs

@@ -205,7 +205,9 @@ impl Brewing {
         }
         // The gate answers the merged file, as the crafting loader's does:
         // a false-conditioned pack file leaves the lower one gone too.
-        sources.retain(|(_, v)| conditions_hold(v));
+        // The data's recipe filters, over the final set.
+        let filters = horizon_items::recipe_filters::RecipeFilters::load(root, overlay);
+        sources.retain_mut(|(id, v)| conditions_hold(v) && filters.apply(id, v));
         sources.sort_by(|a, b| a.0.cmp(&b.0));
         let mut recipes = Vec::new();
         for (id, v) in sources {

crates/horizon-client-render/src/camera.rs

@@ -501,6 +501,19 @@ impl Camera {
         entity: &CameraEntity,
         partial: f32,
         camera_type: CameraType,
+        clip: impl FnMut([f64; 3], [f64; 3]) -> Option<[f64; 3]>,
+    ) {
+        self.align_with_entity_distance(entity, partial, camera_type, |distance| distance, clip);
+    }
+    /// Adjust the detached distance after entity/mount scaling, before collision clipping.
+    /// Only finite overrides in 0..=1024 blocks are accepted (within the game's ray budget).
+    /// First-person views do not call `adjust_distance`.
+    pub fn align_with_entity_distance(
+        &mut self,
+        entity: &CameraEntity,
+        partial: f32,
+        camera_type: CameraType,
+        adjust_distance: impl FnOnce(f32) -> f32,
         mut clip: impl FnMut([f64; 3], [f64; 3]) -> Option<[f64; 3]>,
     ) {
         self.set_rotation(entity.view_y_rot(partial), entity.view_x_rot(partial));
@@ -528,10 +541,14 @@ impl Camera {
                 mount_scale = s;
                 mount_distance = d as f32;
             }
-            let zoom = self.max_zoom(
-                java_max(scale * distance, mount_scale * mount_distance),
-                &mut clip,
-            );
+            let vanilla = java_max(scale * distance, mount_scale * mount_distance);
+            let adjusted = adjust_distance(vanilla);
+            let distance = if adjusted.is_finite() && (0.0..=1024.0).contains(&adjusted) {
+                adjusted
+            } else {
+                vanilla
+            };
+            let zoom = self.max_zoom(distance, &mut clip);
             self.move_by(-zoom, 0.0, 0.0);
         } else if let Some(LivingCamera {
             sleeping: Some(bed),
@@ -969,6 +986,100 @@ mod tests {
         assert!(camera.position[2] > -1.1 && camera.position[2] < -0.9);
     }
     #[test]
+    fn detached_distance_override_keeps_collision_clipping() {
+        let entity = CameraEntity {
+            position: [0.0; 3],
+            previous: [0.0; 3],
+            x_rot: 0.0,
+            y_rot: 0.0,
+            x_rot_o: 0.0,
+            y_rot_o: 0.0,
+            eye_height: 1.62,
+            living: Some(LivingCamera {
+                scale: 2.0,
+                camera_distance: 3.0,
+                sleeping: None,
+                dead: None,
+            }),
+            mount: Some((3.0, 4.0)),
+        };
+        for kind in [CameraType::ThirdPersonBack, CameraType::ThirdPersonFront] {
+            let mut camera = Camera::default();
+            let mut calls = 0;
+            let mut rays = 0;
+            let z = if kind.is_mirrored() { 1.0 } else { -1.0 };
+            camera.align_with_entity_distance(
+                &entity,
+                1.0,
+                kind,
+                |distance| {
+                    assert_eq!(distance, 12.0);
+                    8.0
+                },
+                |_, _| None,
+            );
+            assert!((camera.position[2] - z * 8.0).abs() < 1e-5);
+            camera.align_with_entity_distance(
+                &entity,
+                1.0,
+                kind,
+                |distance| {
+                    calls += 1;
+                    assert_eq!(distance, 12.0);
+                    8.0
+                },
+                |_, _| {
+                    rays += 1;
+                    Some([0.0, 0.0, z])
+                },
+            );
+            assert_eq!((calls, rays), (1, 8));
+            assert!((camera.position[2] - z).abs() < 0.2);
+        }
+    }
+    #[test]
+    fn detached_distance_rejects_invalid_values_and_accepts_zero() {
+        let entity = CameraEntity {
+            position: [0.0; 3],
+            previous: [0.0; 3],
+            x_rot: 0.0,
+            y_rot: 0.0,
+            x_rot_o: 0.0,
+            y_rot_o: 0.0,
+            eye_height: 1.62,
+            living: None,
+            mount: None,
+        };
+        for distance in [f32::NAN, f32::INFINITY, -1.0, 1025.0] {
+            let mut camera = Camera::default();
+            camera.align_with_entity_distance(
+                &entity,
+                1.0,
+                CameraType::ThirdPersonBack,
+                |_| distance,
+                |_, _| None,
+            );
+            assert!((camera.position[2] + 4.0).abs() < 1e-6);
+        }
+        let mut camera = Camera::default();
+        camera.align_with_entity_distance(
+            &entity,
+            1.0,
+            CameraType::ThirdPersonBack,
+            |_| 0.0,
+            |_, _| None,
+        );
+        assert_eq!(camera.position, camera.eye);
+        camera.align_with_entity_distance(
+            &entity,
+            1.0,
+            CameraType::FirstPerson,
+            |_| panic!("first person has no detached distance"),
+            |_, _| None,
+        );
+        assert_eq!(camera.position, camera.eye);
+    }
+    #[test]
     fn fov_modifier_combines_speed_flight_and_bow() {
         let mut p = FovPlayer {
             flying: false,

crates/horizon-client-render/src/chat.rs

@@ -29,6 +29,10 @@ pub type Signature = horizon_protocol::secure_chat::Signature;
 /// How long a message shows before a deletion replaces it
 /// (`ChatComponent.deleteMessageOrDelay`: `addedTime + 60`).
 const DELETION_DELAY: u64 = 60;
+/// The smooth chat extra: the ticks a new line takes to slide in and fade in,
+/// and how far left of its place it starts (GUI pixels).
+const INTRO_TICKS: f32 = 5.0;
+const INTRO_WIDTH: f32 = 12.0;
 
 /// `ChatVisiblity`: the Chat option's three values.
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
@@ -233,14 +237,10 @@ impl Tag {
 
 /// `ChatComponent.AlphaCalculator.timeBased`: opaque for 180 ticks, then
 /// fading out quadratically over 20.
-fn time_alpha(ticks: u64, added: u64) -> f32 {
-    let delta = ticks as i64 - added as i64;
-    let mut t = delta as f64 / 200.0;
-    t = 1.0 - t;
-    t *= 10.0;
-    t = t.clamp(0.0, 1.0);
-    t *= t;
-    t as f32
+fn time_alpha(ticks: f32, added: u64) -> f32 {
+    let mut t = 1.0 - (ticks - added as f32) / 200.0;
+    t = (t * 10.0).clamp(0.0, 1.0);
+    t * t
 }
 #[derive(Default)]
 pub struct Chat {
@@ -256,6 +256,11 @@ pub struct Chat {
     scroll: usize,
     new_since_scroll: bool,
     pub options: ChatOptions,
+    /// The smooth chat extra: a new line slides in from the left while it
+    /// fades in, instead of appearing whole.
+    pub smooth: bool,
+    /// The smooth chat extra: no indicator bar at the left of a line.
+    pub hide_indicator: bool,
     /// Messages printed to stdout as `[CHAT]` (vanilla logs them).
     pub log: bool,
     /// Messages added since the start, for the control socket's events.
@@ -555,7 +560,7 @@ impl Chat {
     }
     /// `ChatComponent.extractRenderState` (background mode unless `focused`)
     /// on a screen `height` GUI pixels tall at `Hud.tickCount` `ticks`.
-    pub fn layout(&self, height: i32, ticks: u64, focused: bool) -> Vec<GuiDraw> {
+    pub fn layout(&self, height: i32, ticks: f32, focused: bool) -> Vec<GuiDraw> {
         let total = self.lines.len();
         if total == 0 {
             return Vec::new();
@@ -569,28 +574,47 @@ impl Chat {
         let entry_height = o.line_height();
         let bottom_to_text =
             (8.0 * (o.line_spacing + 1.0) - 4.0 * o.line_spacing + 0.5).floor() as i32;
+        // Vanilla's 200-tick fade reads the whole GUI ticks
+        // (`Gui.getGuiTicks`); only the smooth chat extra eases it per frame.
+        let fade_ticks = if self.smooth { ticks } else { ticks.floor() };
         let alpha_of = |line: &Line| {
             if focused {
                 1.0
             } else {
-                time_alpha(ticks, line.added)
+                time_alpha(fade_ticks, line.added)
             }
         };
+        // The smooth chat extra: how far into its intro a line is, 0 at the
+        // tick it was added and 1 once it has arrived, as (alpha, offset x).
+        let intro_of = |line: &Line| {
+            if focused || !self.smooth {
+                return (1.0, 0.0);
+            }
+            let t = ((ticks - line.added as f32) / INTRO_TICKS).clamp(0.0, 1.0);
+            let eased = 1.0 - (1.0 - t) * (1.0 - t);
+            (eased, (eased - 1.0) * INTRO_WIDTH)
+        };
         let visible = total
             .saturating_sub(self.scroll)
             .min(self.lines_per_page(focused));
-        let lines: Vec<(usize, &Line, f32)> = (0..visible)
+        let lines: Vec<(usize, &Line, f32, f32)> = (0..visible)
             .rev()
             .map(|i| (i, &self.lines[i + self.scroll]))
-            .map(|(i, line)| (i, line, alpha_of(line)))
-            .filter(|(_, _, alpha)| *alpha > 1.0e-5)
+            .map(|(i, line)| {
+                let (eased, slide) = intro_of(line);
+                (i, line, alpha_of(line) * eased, slide)
+            })
+            .filter(|(_, _, alpha, _)| *alpha > 1.0e-5)
             .collect();
         let mut out = vec![GuiDraw::Push(vec![
             PoseOp::Scale(scale, scale),
             PoseOp::Translate(4.0, 0.0),
         ])];
-        for &(i, _, alpha) in &lines {
+        for &(i, _, alpha, slide) in &lines {
             let bottom = chat_bottom - i as i32 * entry_height;
+            if slide != 0.0 {
+                out.push(GuiDraw::Push(vec![PoseOp::Translate(slide, 0.0)]));
+            }
             out.push(hud_layout::fill(
                 -4,
                 bottom - entry_height,
@@ -598,9 +622,15 @@ impl Chat {
                 bottom,
                 hud_layout::as8(alpha * background_opacity) << 24,
             ));
+            if slide != 0.0 {
+                out.push(GuiDraw::Pop);
+            }
         }
-        for &(i, line, alpha) in &lines {
+        for &(i, line, alpha, slide) in &lines {
             let bottom = chat_bottom - i as i32 * entry_height;
+            if slide != 0.0 {
+                out.push(GuiDraw::Push(vec![PoseOp::Translate(slide, 0.0)]));
+            }
             let opacity = alpha * text_opacity;
             let color = hud_layout::white(opacity);
             if color >> 24 != 0 {
@@ -612,7 +642,7 @@ impl Chat {
                     shadow: true,
                 });
             }
-            if let Some(tag) = &line.tag {
+            if let Some(tag) = line.tag.as_ref().filter(|_| !self.hide_indicator) {
                 let color = hud_layout::as8(opacity) << 24 | tag.color & 0xFF_FFFF;
                 out.push(hud_layout::fill(
                     -4,
@@ -622,6 +652,9 @@ impl Chat {
                     color,
                 ));
             }
+            if slide != 0.0 {
+                out.push(GuiDraw::Pop);
+            }
         }
         if focused {
             let count = lines.len() as i32;
@@ -658,7 +691,7 @@ impl Chat {
     }
     /// Draws [`Chat::layout`] into the HUD batch, and with the chat screen
     /// open the restricted prompt above the lines.
-    pub fn draw(&self, batch: &mut HudBatch, atlas: &HudAtlas, ticks: u64, focused: bool) {
+    pub fn draw(&self, batch: &mut HudBatch, atlas: &HudAtlas, ticks: f32, focused: bool) {
         let draws = self.layout(batch.height as i32, ticks, focused);
         hud_layout::paint(batch, atlas, &draws);
         if focused && self.abilities.any_restriction() {

crates/horizon-client-render/src/chat_tests.rs

@@ -39,6 +39,61 @@ fn add(chat: &mut Chat, font: &Font, content: Text) {
     }
 }
 
+#[test]
+fn smooth_chat_slides_a_line_in_and_can_hide_the_indicator() {
+    let mut chat = Chat {
+        smooth: true,
+        ..Chat::default()
+    };
+    chat.lines.push(Line {
+        added: 0,
+        content: Text::literal("hi"),
+        tag: Some(std::sync::Arc::new(Tag::system_single_player(
+            SYSTEM_INDICATOR,
+        ))),
+    });
+    let text_alpha = |draws: &[GuiDraw]| {
+        draws.iter().find_map(|d| match d {
+            GuiDraw::Text { color, .. } => Some(color >> 24),
+            _ => None,
+        })
+    };
+    // The slide is the negative translate the line carries while it moves.
+    let slide = |draws: &[GuiDraw]| {
+        draws.iter().find_map(|d| match d {
+            GuiDraw::Push(ops) => ops.iter().find_map(|op| match op {
+                PoseOp::Translate(x, _) if *x < 0.0 => Some(*x),
+                _ => None,
+            }),
+            _ => None,
+        })
+    };
+    // The tick it arrives: fully faded out, so nothing is drawn.
+    assert_eq!(text_alpha(&chat.layout(361, 0.0, false)), None);
+    // Halfway through the intro: left of its place and still faint.
+    let halfway = chat.layout(361, INTRO_TICKS / 2.0, false);
+    assert!(slide(&halfway).is_some_and(|x| (-INTRO_WIDTH..0.0).contains(&x)));
+    let faded = text_alpha(&halfway).expect("the line shows halfway through");
+    // Settled: in place and as opaque as vanilla's line.
+    let settled = chat.layout(361, INTRO_TICKS, false);
+    assert_eq!(slide(&settled), None);
+    assert!(text_alpha(&settled).expect("settled") > faded);
+    // The extra off draws the line whole on the tick it arrives, as vanilla.
+    chat.smooth = false;
+    let plain = chat.layout(361, 0.0, false);
+    assert_eq!(slide(&plain), None);
+    assert_eq!(text_alpha(&plain), text_alpha(&settled));
+    // The indicator bar is the -4 to -2 fill at the left of the line.
+    let bar = |draws: &[GuiDraw]| {
+        draws
+            .iter()
+            .any(|d| matches!(d, GuiDraw::Fill { x0: -4, x1: -2, .. }))
+    };
+    assert!(bar(&plain));
+    chat.hide_indicator = true;
+    assert!(!bar(&chat.layout(361, 0.0, false)));
+}
+
 #[test]
 fn clicking_seed_copies_the_raw_value_only_inside_the_link() {
     let font = font();
@@ -95,7 +150,7 @@ fn click_targets_match_rendered_spans_when_scaled_wrapped_and_scrolled() {
             for scroll in [0, 3, 12] {
                 chat.scroll = scroll;
                 let mut links = 0;
-                for draw in chat.layout(361, 0, true) {
+                for draw in chat.layout(361, 0.0, true) {
                     if let GuiDraw::Text { text, x, y, .. } = draw {
                         let mut at = x as f64;
                         for (c, style) in text.chars() {

crates/horizon-client-render/src/cit.rs

@@ -0,0 +1,662 @@
+//! OptiFine's Custom Item Textures (and CIT Resewn's): the rules of the enabled packs'
+//! `optifine/cit/**/*.properties`, read from the overlay resource root. The rules themselves are
+//! `horizon_optifine::cit`'s.
+
+pub use horizon_optifine::cit::{Hand, Kind, Rule};
+
+use horizon_client_core::component::name_text;
+use horizon_client_core::scoreboard::comp_text;
+use horizon_items::item_data::{canon_tag, encode_components};
+use horizon_items::items::ItemStack;
+use horizon_optifine::cit::{ComponentTest, Source, ValueTest};
+use horizon_optifine::{Properties, properties_files_in};
+use horizon_world::nbt::{JavaString, Tag, parse_snbt};
+use std::borrow::Cow;
+use std::collections::HashMap;
+use std::fs;
+use std::hash::{DefaultHasher, Hash, Hasher};
+use std::path::Path;
+use std::sync::Mutex;
+
+/// Every rule under the root's `optifine/cit/`, `mcpatcher/cit/` and CIT Resewn's
+/// `citresewn/cit/` folders, the one chosen first when several match first (`Rule::priority`).
+/// The pack's global `cit.properties` is not a rule.
+pub fn load_rules(root: &Path) -> Vec<Rule> {
+    let tops = ["optifine", "mcpatcher", "citresewn"];
+    let mut rules: Vec<Rule> = properties_files_in(root, &tops, "cit")
+        .into_iter()
+        .filter(|path| !path.ends_with("/cit.properties"))
+        .filter_map(|path| {
+            // Java reads `.properties` as Latin-1: a pack saved that way still loads.
+            let bytes = fs::read(root.join(&path)).ok()?;
+            let text = String::from_utf8(bytes)
+                .unwrap_or_else(|e| e.into_bytes().iter().map(|&b| char::from(b)).collect());
+            let rule = Rule::parse(&path, &Properties::parse_equals_first(&text), |p| {
+                root.join(p).is_file()
+            });
+            if rule.is_none() {
+                log::warn!("custom item textures: {path} is not a rule Horizon can read");
+            }
+            rule
+        })
+        .collect();
+    rules.sort_by(Rule::priority);
+    rules
+}
+
+/// The rules with an index by item and a cache of what each stack matched.
+#[derive(Debug, Default)]
+pub struct CitRules {
+    pub rules: Vec<Rule>,
+    /// Per kind (`Kind as usize`), the rules naming each item, in priority order.
+    by_item: [HashMap<String, Vec<u32>>; 4],
+    /// Enchantment rules without `items`, in priority order.
+    any_item: Vec<u32>,
+    /// Per rule, per component test: its literal read as SNBT and as a JSON text component.
+    literals: Vec<Vec<Prepared>>,
+    selected: Mutex<HashMap<u64, Option<u32>>>,
+    enchanted: Mutex<HashMap<u64, Vec<u32>>>,
+}
+
+#[derive(Debug, Default)]
+struct Prepared {
+    snbt: Option<Tag>,
+    json: Option<String>,
+}
+
+/// Cache entries kept before the cache starts over.
+const CACHE_LIMIT: usize = 4096;
+
+impl CitRules {
+    /// The enabled packs' rules under the overlay resource root.
+    pub fn load(root: &Path) -> Self {
+        Self::new(load_rules(root))
+    }
+
+    /// `rules` in priority order, the winner first.
+    pub fn new(rules: Vec<Rule>) -> Self {
+        let mut by_item: [HashMap<String, Vec<u32>>; 4] = Default::default();
+        let mut any_item = Vec::new();
+        for (i, rule) in rules.iter().enumerate() {
+            let i = i as u32;
+            if rule.kind == Kind::Enchantment && rule.items.is_empty() {
+                any_item.push(i);
+            }
+            for item in &rule.items {
+                let list = by_item[rule.kind as usize].entry(item.clone()).or_default();
+                if list.last() != Some(&i) {
+                    list.push(i);
+                }
+            }
+        }
+        let literals = rules
+            .iter()
+            .map(|r| r.components.iter().map(prepare).collect())
+            .collect();
+        Self {
+            rules,
+            by_item,
+            any_item,
+            literals,
+            ..Default::default()
+        }
+    }
+
+    pub fn is_empty(&self) -> bool {
+        self.rules.is_empty()
+    }
+
+    /// The winning rule of `kind` (Item, Armor or Elytra) for this stack, as an index into `rules`.
+    pub fn select(
+        &self,
+        kind: Kind,
+        stack: &ItemStack,
+        hand: Hand,
+        max_damage: u32,
+    ) -> Option<usize> {
+        let candidates = self.by_item[kind as usize].get(&*stack.item)?;
+        let comps = encode_components(stack);
+        let key = cache_key((0, kind, hand), stack, max_damage, comps.as_ref());
+        if let Some(hit) = lock(&self.selected).get(&key) {
+            return hit.map(|i| i as usize);
+        }
+        let found = candidates
+            .iter()
+            .copied()
+            .find(|&i| self.matches(i, stack, Some(hand), max_damage, comps.as_ref()));
+        remember(&self.selected, key, found);
+        found.map(|i| i as usize)
+    }
+
+    /// Every matching Enchantment rule, in priority order (layers are the glint PR's business).
+    pub fn enchantments(&self, stack: &ItemStack, max_damage: u32) -> Vec<usize> {
+        let named = self.by_item[Kind::Enchantment as usize]
+            .get(&*stack.item)
+            .map_or(&[][..], Vec::as_slice);
+        if named.is_empty() && self.any_item.is_empty() {
+            return Vec::new();
+        }
+        let comps = encode_components(stack);
+        let key = cache_key(
+            (1, Kind::Enchantment, Hand::Any),
+            stack,
+            max_damage,
+            comps.as_ref(),
+        );
+        let hit = lock(&self.enchanted).get(&key).cloned();
+        let found = hit.unwrap_or_else(|| {
+            let mut all: Vec<u32> = named.iter().chain(&self.any_item).copied().collect();
+            all.sort_unstable();
+            all.retain(|&i| self.matches(i, stack, None, max_damage, comps.as_ref()));
+            remember(&self.enchanted, key, all.clone());
+            all
+        });
+        found.into_iter().map(|i| i as usize).collect()
+    }
+
+    /// Whether rule `i` matches; `hand` None skips the hand test (enchantment glints).
+    fn matches(
+        &self,
+        i: u32,
+        stack: &ItemStack,
+        hand: Option<Hand>,
+        max_damage: u32,
+        comps: Option<&Tag>,
+    ) -> bool {
+        let rule = &self.rules[i as usize];
+        if hand.is_some_and(|h| rule.hand != Hand::Any && rule.hand != h) {
+            return false;
+        }
+        let count = i32::try_from(stack.count).unwrap_or(i32::MAX);
+        if rule.stack_size.as_ref().is_some_and(|r| !r.contains(count)) {
+            return false;
+        }
+        // CIT Resewn: only damageable items have damage.
+        let damage = if max_damage > 0 { stack.damage } else { 0 };
+        if rule
+            .damage
+            .as_ref()
+            .is_some_and(|d| !d.matches(damage, max_damage))
+        {
+            return false;
+        }
+        let enchantments = stack.crafting_enchantments();
+        let listed = |id: &str| rule.enchantments.iter().any(|e| e == id);
+        if !rule.enchantments.is_empty() && !enchantments.iter().any(|(id, _)| listed(id)) {
+            return false;
+        }
+        if let Some(levels) = &rule.enchantment_levels {
+            let level_in_range = enchantments.iter().any(|(id, level)| {
+                (rule.enchantments.is_empty() || listed(id))
+                    && levels.contains(i32::try_from(*level).unwrap_or(i32::MAX))
+            });
+            if !level_in_range {
+                return false;
+            }
+        }
+        let literals = &self.literals[i as usize];
+        rule.components
+            .iter()
+            .zip(literals)
+            .all(|(test, lit)| component_test(test, lit, stack, comps) != test.negate)
+    }
+}
+
+fn lock<T>(m: &Mutex<T>) -> std::sync::MutexGuard<'_, T> {
+    m.lock().unwrap_or_else(|e| e.into_inner())
+}
+
+fn remember<V>(cache: &Mutex<HashMap<u64, V>>, key: u64, value: V) {
+    let mut cache = lock(cache);
+    if cache.len() >= CACHE_LIMIT {
+        cache.clear();
+    }
+    cache.insert(key, value);
+}
+
+/// What a cached answer depends on; `query` tells `select` from `enchantments`.
+fn cache_key(query: (u8, Kind, Hand), stack: &ItemStack, max: u32, comps: Option<&Tag>) -> u64 {
+    let mut h = DefaultHasher::new();
+    (query.0, query.1 as u8, query.2 as u8, &*stack.item).hash(&mut h);
+    (stack.count, stack.damage, max, comps).hash(&mut h);
+    h.finish()
+}
+
+fn prepare(test: &ComponentTest) -> Prepared {
+    let ValueTest::Literal(lit) = &test.value else {
+        return Prepared::default();
+    };
+    let text = lit.text.trim();
+    let snbt = match parse_snbt(text) {
+        Ok((tag, read)) if read == text.len() && text.starts_with(['{', '[']) => Some(tag),
+        _ => None,
+    };
+    let json = json_plain(text);
+    Prepared { snbt, json }
+}
+
+/// The plain text of `s` read as a JSON text component.
+fn json_plain(s: &str) -> Option<String> {
+    if !s.starts_with(['{', '[', '"']) {
+        return None;
+    }
+    let value: serde_json::Value = serde_json::from_str(s).ok()?;
+    Some(comp_text(&value).plain())
+}
+
+/// Whether one test passes, before its `negate`.
+fn component_test(
+    test: &ComponentTest,
+    lit: &Prepared,
+    stack: &ItemStack,
+    comps: Option<&Tag>,
+) -> bool {
+    let legacy;
+    let (root, text_depth) = match &test.source {
+        Source::Component(id) => {
+            let depth = match id.as_str() {
+                "minecraft:custom_name" | "minecraft:item_name" => Some(0),
+                "minecraft:lore" => Some(1),
+                _ => None,
+            };
+            (comps.and_then(|c| c.get(id)), depth)
+        }
+        Source::LegacyEnchantments { stored } => {
+            let levels = if *stored {
+                stack.stored_enchantments()
+            } else {
+                stack.enchantments()
+            };
+            legacy = Tag::List(
+                levels
+                    .iter()
+                    .map(|(id, lvl)| {
+                        let lvl = i16::try_from(*lvl).unwrap_or(i16::MAX);
+                        Tag::compound([
+                            ("id", Tag::String((&**id).into())),
+                            ("lvl", Tag::Short(lvl)),
+                        ])
+                    })
+                    .collect(),
+            );
+            (Some(&legacy), None)
+        }
+    };
+    // Fields the component leaves out when 0, which pre-1.20.5 items always wrote.
+    let defaulted;
+    let root = match (&test.source, root, test.path.first()) {
+        (Source::Component(id), Some(Tag::Compound(map)), Some(field))
+            if matches!(
+                (id.as_str(), field.as_str()),
+                ("minecraft:written_book_content", "generation")
+                    | ("minecraft:fireworks", "flight_duration")
+            ) && !map.contains_key(&JavaString::from(field.as_str())) =>
+        {
+            let mut map = map.clone();
+            map.insert(JavaString::from(field.as_str()), Tag::Int(0));
+            defaulted = Tag::Compound(map);
+            Some(&defaulted)
+        }
+        (_, root, _) => root,
+    };
+    let Some(root) = root else {
+        return matches!(test.value, ValueTest::Exists(false));
+    };
+    if let ValueTest::Exists(want) = test.value {
+        return walk(root, &test.path, 0, &mut |_, _| true) == want;
+    }
+    walk(root, &test.path, 0, &mut |tag, depth| {
+        value_test(&test.value, lit, tag, text_depth == Some(depth))
+    })
+}
+
+/// Visits what `path` reaches from `tag`, true once `visit` is.
+fn walk(
+    tag: &Tag,
+    path: &[String],
+    depth: usize,
+    visit: &mut dyn FnMut(&Tag, usize) -> bool,
+) -> bool {
+    let Some((seg, rest)) = path.split_first() else {
+        return visit(tag, depth);
+    };
+    let mut next = |t: &Tag| walk(t, rest, depth + 1, visit);
+    let len = match tag {
+        Tag::Compound(map) if seg == "*" => return map.values().any(&mut next),
+        Tag::Compound(map) => return map.get(&JavaString::from(seg.as_str())).is_some_and(next),
+        Tag::List(v) => v.len(),
+        Tag::ByteArray(v) => v.len(),
+        Tag::IntArray(v) => v.len(),
+        Tag::LongArray(v) => v.len(),
+        _ => return false,
+    };
+    let element = |i: usize| match tag {
+        Tag::List(v) => Cow::Borrowed(&v[i]),
+        Tag::ByteArray(v) => Cow::Owned(Tag::Byte(v[i] as i8)),
+        Tag::IntArray(v) => Cow::Owned(Tag::Int(v[i])),
+        Tag::LongArray(v) => Cow::Owned(Tag::Long(v[i])),
+        _ => Cow::Owned(Tag::End),
+    };
+    if seg == "count" {
+        return next(&Tag::Int(i32::try_from(len).unwrap_or(i32::MAX)));
+    }
+    if seg == "*" {
+        return (0..len).any(|i| next(&element(i)));
+    }
+    seg.parse::<usize>()
+        .ok()
+        .filter(|&i| i < len)
+        .is_some_and(|i| next(&element(i)))
+}
+
+fn int_value(tag: &Tag) -> Option<i64> {
+    match *tag {
+        Tag::Byte(v) => Some(v.into()),
+        Tag::Short(v) => Some(v.into()),
+        Tag::Int(v) => Some(v.into()),
+        Tag::Long(v) => Some(v),
+        _ => None,
+    }
+}
+
+/// A number as Java's `String.valueOf` writes it (`3`, `3.0`).
+fn decimal(tag: &Tag) -> Option<String> {
+    let s = match *tag {
+        Tag::Float(b) => f32::from_bits(b).to_string(),
+        Tag::Double(b) => f64::from_bits(b).to_string(),
+        _ => return int_value(tag).map(|v| v.to_string()),
+    };
+    Some(if s.contains(['.', 'e', 'N', 'i']) {
+        s
+    } else {
+        s + ".0"
+    })
+}
+
+/// `text` against a string, its JSON text, or the plain text of a text component.
+fn text_matches(tag: &Tag, is_text: bool, text: impl Fn(&str) -> bool) -> bool {
+    match tag {
+        Tag::String(s) => {
+            let s = s.to_string_lossy();
+            text(&s)
+                || (is_text && text(&name_text(tag).plain()))
+                || json_plain(&s).is_some_and(|p| text(&p))
+        }
+        Tag::Compound(_) | Tag::List(_) => is_text && text(&name_text(tag).plain()),
+        _ => false,
+    }
+}
+
+fn value_test(test: &ValueTest, lit: &Prepared, tag: &Tag, is_text: bool) -> bool {
+    match test {
+        ValueTest::Exists(_) => true,
+        ValueTest::Range(r) => {
+            int_value(tag).is_some_and(|v| i32::try_from(v).is_ok_and(|v| r.contains(v)))
+        }
+        ValueTest::Raw(name) => name.matches(&canon_tag(tag)),
+        ValueTest::Text(name) => match decimal(tag) {
+            Some(n) => name.matches(&n),
+            None => text_matches(tag, is_text, |s| name.matches(s)),
+        },
+        ValueTest::Literal(l) => match tag {
+            Tag::Float(b) => l.text.trim().parse::<f32>().ok() == Some(f32::from_bits(*b)),
+            Tag::Double(b) => l.float == Some(f64::from_bits(*b)),
+            Tag::Compound(_) | Tag::List(_)
+                if lit.snbt.as_ref().is_some_and(|e| contains(e, tag)) =>
+            {
+                true
+            }
+            _ => match int_value(tag) {
+                Some(v) => l.int == Some(v),
+                None => text_matches(tag, is_text, |s| {
+                    s == l.text || lit.json.as_deref() == Some(s)
+                }),
+            },
+        },
+    }
+}
+
+/// `NbtUtils.compareNbt(expected, actual, true)`: every key and element of `expected` found in
+/// `actual`.
+fn contains(expected: &Tag, actual: &Tag) -> bool {
+    match (expected, actual) {
+        (Tag::Compound(e), Tag::Compound(a)) => e
+            .iter()
+            .all(|(k, v)| a.get(k).is_some_and(|a| contains(v, a))),
+        (Tag::List(e), Tag::List(a)) if e.is_empty() => a.is_empty(),
+        (Tag::List(e), Tag::List(a)) => e.iter().all(|e| a.iter().any(|a| contains(e, a))),
+        _ => expected == actual,
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::sync::Arc;
+
+    /// Rules from (file stem, properties), sorted as `load_rules` sorts them.
+    fn rules(files: &[(&str, &str)]) -> CitRules {
+        let mut rules: Vec<Rule> = files
+            .iter()
+            .map(|(stem, text)| {
+                let path = format!("assets/minecraft/optifine/cit/{stem}.properties");
+                let text = format!("texture=x\n{text}");
+                Rule::parse(&path, &Properties::parse_equals_first(&text), |_| true).unwrap()
+            })
+            .collect();
+        rules.sort_by(Rule::priority);
+        CitRules::new(rules)
+    }
+
+    fn stem(cit: &CitRules, i: Option<usize>) -> Option<&str> {
+        let path = &cit.rules[i?].path;
+        path.rsplit('/').next()?.strip_suffix(".properties")
+    }
+
+    fn item(cit: &CitRules, stack: ItemStack) -> Option<&str> {
+        stem(cit, cit.select(Kind::Item, &stack, Hand::Main, 0))
+    }
+
+    fn new(id: &str) -> ItemStack {
+        ItemStack::new(&format!("minecraft:{id}"), 1)
+    }
+
+    fn string(s: &str) -> Tag {
+        Tag::String(s.into())
+    }
+
+    fn with(id: &str, component: &str, tag: Tag) -> ItemStack {
+        let mut stack = new(id);
+        let component = format!("minecraft:{component}");
+        stack.data_mut().other.push((component, tag));
+        stack
+    }
+
+    fn enchanted(id: &str, levels: &[(&str, u32)]) -> ItemStack {
+        let mut stack = new(id);
+        let levels = levels
+            .iter()
+            .map(|(e, l)| (Arc::from(format!("minecraft:{e}")), *l));
+        stack.data_mut().enchantments = levels.collect();
+        stack
+    }
+
+    #[test]
+    fn heavier_rules_win_and_kinds_stay_apart() {
+        let cit = rules(&[
+            ("plain", "items=stick"),
+            ("heavy", "items=stick\nweight=2\nstackSize=2-"),
+            ("offhand", "items=stick\nweight=5\nhand=off"),
+            ("armor", "type=armor\nitems=stick"),
+            ("wings", "type=elytra"),
+        ]);
+        assert_eq!(item(&cit, new("stick")), Some("plain"));
+        assert_eq!(
+            item(&cit, ItemStack::new("minecraft:stick", 3)),
+            Some("heavy")
+        );
+        let pick = |kind, id, hand, max| stem(&cit, cit.select(kind, &new(id), hand, max));
+        assert_eq!(pick(Kind::Item, "stick", Hand::Off, 0), Some("offhand"));
+        assert_eq!(item(&cit, new("stone")), None);
+        assert_eq!(item(&cit, new("elytra")), None);
+        assert_eq!(pick(Kind::Elytra, "elytra", Hand::Main, 432), Some("wings"));
+        assert_eq!(pick(Kind::Armor, "stick", Hand::Main, 0), Some("armor"));
+    }
+
+    #[test]
+    fn names_match_by_their_plain_text() {
+        let cit = rules(&[
+            ("glob", "items=stick\nnbt.display.Name=ipattern:*sword"),
+            ("exact", "items=stone\ncomponents.custom_name=My Sword"),
+            ("json", "items=dirt\nnbt.display.Name=[\"My \",\"Sword\"]"),
+        ]);
+        let named = |id: &str, name: Tag| {
+            let mut stack = new(id);
+            stack.data_mut().custom_name = Some(name);
+            stack
+        };
+        let styled = Tag::compound([("text", string("My Sword")), ("color", string("red"))]);
+        assert_eq!(item(&cit, named("stick", styled.clone())), Some("glob"));
+        assert_eq!(item(&cit, named("stick", string("Blade"))), None);
+        assert_eq!(item(&cit, new("stick")), None);
+        assert_eq!(item(&cit, named("stone", styled.clone())), Some("exact"));
+        assert_eq!(item(&cit, named("dirt", styled)), Some("json"));
+    }
+
+    #[test]
+    fn lore_lines_and_list_counts() {
+        let cit = rules(&[
+            (
+                "any_line",
+                "items=stick\nnbt.display.Lore.*=ipattern:*legendary*",
+            ),
+            ("two_lines", "items=stone\ncomponents.lore.count=2"),
+        ]);
+        let bold = Tag::compound([("text", string("A LEGENDARY item")), ("bold", Tag::Byte(1))]);
+        let lore = Tag::List(vec![string("Common"), bold]);
+        assert_eq!(
+            item(&cit, with("stick", "lore", lore.clone())),
+            Some("any_line")
+        );
+        assert_eq!(item(&cit, with("stone", "lore", lore)), Some("two_lines"));
+        let one = Tag::List(vec![string("A legendary item")]);
+        assert_eq!(item(&cit, with("stone", "lore", one)), None);
+    }
+
+    #[test]
+    fn custom_data_existence_and_negation() {
+        let cit = rules(&[
+            (
+                "aote",
+                "items=stick\nweight=2\nnbt.ExtraAttributes.id=ASPECT_OF_THE_END",
+            ),
+            (
+                "not_hyp",
+                "items=stick\nweight=1\ncomponent.custom_data.ExtraAttributes.id=!HYP",
+            ),
+            ("unnamed", "items=stick\nnbt.display.Name=exists:false"),
+        ]);
+        let data = |id: &str| {
+            let attributes =
+                Tag::compound([("ExtraAttributes", Tag::compound([("id", string(id))]))]);
+            with("stick", "custom_data", attributes)
+        };
+        assert_eq!(item(&cit, data("ASPECT_OF_THE_END")), Some("aote"));
+        assert_eq!(item(&cit, data("MIDAS")), Some("not_hyp"));
+        assert_eq!(item(&cit, data("HYP")), Some("unnamed"));
+        let mut named = data("HYP");
+        named.data_mut().custom_name = Some(string("Hyperion"));
+        assert_eq!(item(&cit, named), None);
+    }
+
+    #[test]
+    fn legacy_enchantment_lists_and_model_data() {
+        let cit = rules(&[
+            (
+                "sharp",
+                "items=stick\nnbt.Enchantments.*.id=minecraft:sharpness\nnbt.Enchantments.0.lvl=5",
+            ),
+            ("cmd", "items=stone\nnbt.CustomModelData=3"),
+            (
+                "cmd_snbt",
+                "items=dirt\ncomponents.custom_model_data={floats:[3.0f]}",
+            ),
+        ]);
+        assert_eq!(
+            item(&cit, enchanted("stick", &[("sharpness", 5)])),
+            Some("sharp")
+        );
+        assert_eq!(item(&cit, enchanted("stick", &[("sharpness", 4)])), None);
+        let model = |id: &str, f: f32| {
+            let floats = Tag::List(vec![Tag::Float(f.to_bits()), Tag::Float(7f32.to_bits())]);
+            with(id, "custom_model_data", Tag::compound([("floats", floats)]))
+        };
+        assert_eq!(item(&cit, model("stone", 3.0)), Some("cmd"));
+        assert_eq!(item(&cit, model("stone", 3.5)), None);
+        assert_eq!(item(&cit, model("dirt", 3.0)), Some("cmd_snbt"));
+        assert_eq!(item(&cit, model("dirt", 2.0)), None);
+    }
+
+    #[test]
+    fn fields_left_out_at_zero_read_as_zero() {
+        let cit = rules(&[("zero", "items=firework_rocket\nnbt.Fireworks.Flight=0")]);
+        let mut rocket = new("firework_rocket");
+        rocket.data_mut().fireworks = Some((0, Vec::new()));
+        assert_eq!(item(&cit, rocket.clone()), Some("zero"));
+        rocket.data_mut().fireworks = Some((2, Vec::new()));
+        assert_eq!(item(&cit, rocket), None);
+    }
+
+    #[test]
+    fn damage_counts_only_for_damageable_items() {
+        let cit = rules(&[
+            ("worn", "items=diamond_sword\ndamage=50-100%"),
+            ("new", "items=stick\ndamage=0"),
+        ]);
+        let damaged = |id: &str, damage: u32, max: u32| {
+            let mut stack = new(id);
+            stack.damage = damage;
+            stem(&cit, cit.select(Kind::Item, &stack, Hand::Main, max))
+        };
+        // Half of 1561 is 780.5.
+        assert_eq!(damaged("diamond_sword", 780, 1561), None);
+        assert_eq!(damaged("diamond_sword", 781, 1561), Some("worn"));
+        assert_eq!(damaged("stick", 5, 0), Some("new"));
+    }
+
+    #[test]
+    fn enchantment_levels_and_rules_for_any_item() {
+        let cit = rules(&[
+            (
+                "sharp3",
+                "items=stick\nenchantments=sharpness\nenchantmentLevels=3-",
+            ),
+            ("any3", "items=stone\nenchantmentLevels=3-"),
+            ("glint", "type=enchantment\nenchantments=sharpness"),
+            (
+                "sword_glint",
+                "type=enchantment\nitems=diamond_sword\nweight=2",
+            ),
+        ]);
+        let mixed = [("sharpness", 2), ("unbreaking", 3)];
+        assert_eq!(item(&cit, enchanted("stick", &mixed)), None);
+        assert_eq!(
+            item(&cit, enchanted("stick", &[("sharpness", 4)])),
+            Some("sharp3")
+        );
+        assert_eq!(item(&cit, enchanted("stone", &mixed)), Some("any3"));
+        let glints = |stack: ItemStack| -> Vec<&str> {
+            let found = cit.enchantments(&stack, 0).into_iter();
+            found.map(|i| stem(&cit, Some(i)).unwrap()).collect()
+        };
+        let sharp = [("sharpness", 1)];
+        assert_eq!(
+            glints(enchanted("diamond_sword", &sharp)),
+            ["sword_glint", "glint"]
+        );
+        assert_eq!(glints(enchanted("stick", &sharp)), ["glint"]);
+        assert!(glints(new("stick")).is_empty());
+        // Glints are never an item's texture.
+        assert_eq!(item(&cit, enchanted("diamond_sword", &sharp)), None);
+    }
+}

crates/horizon-client-render/src/clouds.rs

@@ -1,7 +1,15 @@
 //! Cloud visibility and flat/fancy cell geometry (`CloudRenderer`).
+/// `EnvironmentAttributes.CLOUD_HEIGHT`'s default, and the overworld's `visual/cloud_height`.
+pub const CLOUD_HEIGHT: f64 = 192.33;
+
+/// Whether the cloud color has any packed alpha (vanilla gates the clouds on it).
+pub fn has_color(alpha: f32) -> bool {
+    (alpha.clamp(0.0, 1.0) * 255.0) as u8 > 0
+}
+
 /// `LevelRenderer`: skip OFF clouds and colors with no packed alpha.
 pub fn visible(mode: &str, alpha: f32) -> bool {
-    mode != "false" && (alpha.clamp(0.0, 1.0) * 255.0) as u8 > 0
+    mode != "false" && has_color(alpha)
 }
 
 /// `buildFlatCell`: bottom plane, in both windings for the culled cloud pipeline.
@@ -110,7 +118,7 @@ impl Input<'_> {
         z -= (z / th).floor() * th;
         let cell_x = (x / 12.0).floor() as i64;
         let cell_z = (z / 12.0).floor() as i64;
-        let bottom = (192.33 - self.camera.y) as f32;
+        let bottom = (CLOUD_HEIGHT - self.camera.y) as f32;
         let key = MeshKey {
             cell_x,
             cell_z,

crates/horizon-client-render/src/connected.rs

@@ -0,0 +1,724 @@
+//! OptiFine connected textures (`optifine/ctm`) at mesh time. The active packs' rules are read
+//! once at load, their tiles become sprite layers, and each block state and sprite layer gets
+//! the short list of rules that can touch it; meshing a face then walks only those lists
+//! ([`ConnectedTextures::pick`]). Without CTM files there are no rules and nothing changes.
+//!
+//! The rules and the tile geometry are `horizon_optifine::ctm`'s.
+
+use crate::sprites::Sprites;
+use horizon_optifine::ctm::{
+    self, Connect, Method, Orient, Rule, Tile,
+    connect::{self as geometry, Axes, Axis, Face},
+};
+use horizon_world::block_state_properties::BlockProperties;
+use horizon_world::registry::{BlockRegistry, BlockStateId};
+use std::{collections::HashMap, path::Path};
+
+/// A tile as the mesher draws it.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum TileLayer {
+    Layer {
+        layer: u16,
+        /// The sprite has fractional alpha (drawn in the translucent pass).
+        translucent: bool,
+        /// Every texel is opaque (drawn without an alpha test).
+        opaque: bool,
+    },
+    /// Try the next rule.
+    Skip,
+    /// The face's own sprite.
+    Default,
+}
+
+/// What a face draws.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum Pick {
+    /// Its own sprite.
+    Keep,
+    Tile(TileLayer),
+    /// `ctm_compact`: a tile per quarter of the sprite (top-left, top-right, bottom-left,
+    /// bottom-right).
+    Quarters([TileLayer; 4]),
+}
+
+struct LoadedRule {
+    rule: Rule,
+    tiles: Vec<TileLayer>,
+}
+
+#[derive(Clone, Copy, Default)]
+struct StateInfo {
+    /// Index of the state's block (`connect=block`).
+    block: u32,
+    axis: Option<Axis>,
+    /// `half=upper`: `linked` random tiles follow the lower half.
+    upper: bool,
+}
+
+#[derive(Default)]
+pub struct ConnectedTextures {
+    rules: Vec<LoadedRule>,
+    /// By block state, then by sprite layer: ranges of `lists` (rule indices, in rule order).
+    by_state: Vec<(u32, u32)>,
+    by_layer: Vec<(u32, u32)>,
+    lists: Vec<u16>,
+    states: Vec<StateInfo>,
+    /// By block state: the sprite of its model's face on each side (`connect=tile`); empty
+    /// when no rule connects by tile.
+    face_layers: Vec<[u16; 6]>,
+}
+
+/// `list` appended to `lists`, as its range there.
+fn push_list(lists: &mut Vec<u16>, list: &[u16]) -> (u32, u32) {
+    let start = lists.len() as u32;
+    lists.extend_from_slice(list);
+    (start, list.len() as u32)
+}
+
+/// The sprite name of a texture resource path: `ns:path` under `textures/`, else the path
+/// itself (as [`Sprites::insert_file`] names a tile).
+fn sprite_name(resource: &str) -> String {
+    let parts = resource
+        .strip_prefix("assets/")
+        .and_then(|p| p.split_once('/'))
+        .and_then(|(ns, p)| Some((ns, p.strip_prefix("textures/")?.strip_suffix(".png")?)));
+    match parts {
+        Some((ns, path)) => format!("{ns}:{path}"),
+        None => resource.to_owned(),
+    }
+}
+
+impl ConnectedTextures {
+    /// The rules under `root`, with their tiles inserted into `sprites` (before it finishes).
+    /// `face_layer` answers a block state's sprite on a side, for rules that connect by tile.
+    pub fn load(
+        root: &Path,
+        registry: &BlockRegistry,
+        sprites: &mut Sprites,
+        mut face_layer: impl FnMut(BlockStateId, Face) -> Option<u32>,
+    ) -> Self {
+        let mut rules = ctm::load(root);
+        // Rules no face can use load no tiles: overlays (not drawn yet), and custom names (section
+        // meshes see no block entity).
+        rules.retain(|r| !r.method.is_overlay() && r.name.is_none());
+        // Rule indices are `u16`.
+        rules.truncate(usize::from(u16::MAX));
+        if rules.is_empty() {
+            return Self::default();
+        }
+        let loaded = rules
+            .into_iter()
+            .filter_map(|rule| {
+                let tiles = rule
+                    .tiles
+                    .iter()
+                    .map(|tile| match tile {
+                        Tile::Skip => Ok(TileLayer::Skip),
+                        Tile::Default => Ok(TileLayer::Default),
+                        Tile::Texture(path) => {
+                            // A tile among the textures is that sprite, under its own name.
+                            let layer = match sprite_name(path) {
+                                name if name != *path => sprites.insert(root, &name)?,
+                                _ => sprites.insert_file(root, path)?,
+                            };
+                            Ok(TileLayer::Layer {
+                                layer: u16::try_from(layer)?,
+                                translucent: sprites.translucent[layer as usize],
+                                opaque: sprites.opaque[layer as usize],
+                            })
+                        }
+                    })
+                    .collect::<crate::Result<Vec<_>>>();
+                match tiles {
+                    Ok(tiles) => Some(LoadedRule { rule, tiles }),
+                    Err(e) => {
+                        log::warn!("Horizon: connected textures {}: a tile: {e}", rule.path);
+                        None
+                    }
+                }
+            })
+            .collect();
+        let states = (0..registry.len() as u32).map(|id| {
+            registry
+                .state(BlockStateId(id))
+                .map(|s| (s.name.as_str(), &s.properties))
+        });
+        let mut out = Self::build(loaded, states, |name| sprites.layers.get(name).copied());
+        if out.rules.iter().any(|r| r.rule.connect == Connect::Tile) {
+            out.face_layers = (0..registry.len() as u32)
+                .map(|id| {
+                    Face::ALL
+                        .map(|f| face_layer(BlockStateId(id), f).map_or(u16::MAX, |l| l as u16))
+                })
+                .collect();
+        }
+        out
+    }
+
+    /// The lookups for `rules` (already ordered) over every block state (`None` for an id the
+    /// registry skips), `layer` answering a sprite name's layer.
+    fn build<'a>(
+        rules: Vec<LoadedRule>,
+        states: impl Iterator<Item = Option<(&'a str, &'a BlockProperties)>>,
+        layer: impl Fn(&str) -> Option<u32>,
+    ) -> Self {
+        let mut out = Self {
+            rules,
+            ..Self::default()
+        };
+        let mut blocks = HashMap::new();
+        let mut by_layer: Vec<Vec<u16>> = Vec::new();
+        // Block rules by the block each entry names, so a state tests only its own.
+        let mut by_block: HashMap<&str, Vec<u16>> = HashMap::new();
+        for (i, r) in out.rules.iter().enumerate() {
+            let i = i as u16;
+            for tile in &r.rule.match_tiles {
+                if let Some(l) = layer(&sprite_name(tile)) {
+                    let l = l as usize;
+                    if by_layer.len() <= l {
+                        by_layer.resize(l + 1, Vec::new());
+                    }
+                    if by_layer[l].last() != Some(&i) {
+                        by_layer[l].push(i);
+                    }
+                }
+            }
+            for m in &r.rule.match_blocks {
+                let list = by_block.entry(m.id.as_str()).or_default();
+                if list.last() != Some(&i) {
+                    list.push(i);
+                }
+            }
+        }
+        for list in by_layer {
+            let range = push_list(&mut out.lists, &list);
+            out.by_layer.push(range);
+        }
+        let mut list = Vec::new();
+        for state in states {
+            let Some((name, props)) = state else {
+                out.by_state.push((0, 0));
+                out.states.push(StateInfo::default());
+                continue;
+            };
+            let next = blocks.len() as u32;
+            let block = *blocks.entry(name).or_insert(next);
+            let prop = |k: &str| props.get(k).map(String::as_str);
+            out.states.push(StateInfo {
+                block,
+                axis: match prop("axis") {
+                    Some("x") => Some(Axis::X),
+                    Some("y") => Some(Axis::Y),
+                    Some("z") => Some(Axis::Z),
+                    _ => None,
+                },
+                upper: prop("half") == Some("upper"),
+            });
+            list.clear();
+            if let Some(candidates) = by_block.get(name) {
+                list.extend(
+                    candidates
+                        .iter()
+                        .filter(|&&i| out.rules[usize::from(i)].rule.matches_block(name, prop)),
+                );
+            }
+            let range = push_list(&mut out.lists, &list);
+            out.by_state.push(range);
+        }
+        out
+    }
+
+    pub fn is_empty(&self) -> bool {
+        self.rules.is_empty()
+    }
+
+    fn list(&self, ranges: &[(u32, u32)], i: usize) -> &[u16] {
+        ranges.get(i).map_or(&[], |&(start, len)| {
+            &self.lists[start as usize..(start + len) as usize]
+        })
+    }
+
+    /// What the `face` of the block `state` at `pos` draws, for a quad with sprite `layer`.
+    /// `neighbour` answers the state at an offset from the block; `biome` its biome, asked only
+    /// by rules that test one.
+    pub fn pick<'b>(
+        &self,
+        state: u32,
+        layer: u16,
+        face: Face,
+        pos: [i32; 3],
+        neighbour: impl Fn([i32; 3]) -> u32,
+        biome: impl Fn() -> Option<&'b str>,
+    ) -> Pick {
+        let (mut by_state, mut by_layer) = (
+            self.list(&self.by_state, state as usize),
+            self.list(&self.by_layer, layer as usize),
+        );
+        // Both lists are in rule order: walk them as one. A rule naming blocks and tiles needs
+        // both (it is in both lists); one naming either needs that one.
+        loop {
+            let (i, block, tile) = match (by_state.split_first(), by_layer.split_first()) {
+                (None, None) => return Pick::Keep,
+                (Some((&x, rest)), Some((&y, other))) if x == y => {
+                    (by_state, by_layer) = (rest, other);
+                    (x, true, true)
+                }
+                (Some((&x, rest)), Some((&y, _))) if x < y => {
+                    by_state = rest;
+                    (x, true, false)
+                }
+                (Some((&x, rest)), None) => {
+                    by_state = rest;
+                    (x, true, false)
+                }
+                (_, Some((&y, rest))) => {
+                    by_layer = rest;
+                    (y, false, true)
+                }
+            };
+            let r = &self.rules[usize::from(i)];
+            if (block || r.rule.match_blocks.is_empty())
+                && (tile || r.rule.match_tiles.is_empty())
+                && let Some(pick) = self.apply(r, state, layer, face, pos, &neighbour, &biome)
+            {
+                return pick;
+            }
+        }
+    }
+
+    /// One rule on a face: `None` when it doesn't apply or picks `<skip>`.
+    #[allow(clippy::too_many_arguments)]
+    fn apply<'b>(
+        &self,
+        r: &LoadedRule,
+        state: u32,
+        layer: u16,
+        face: Face,
+        pos: [i32; 3],
+        neighbour: &impl Fn([i32; 3]) -> u32,
+        biome: &impl Fn() -> Option<&'b str>,
+    ) -> Option<Pick> {
+        let rule = &r.rule;
+        // `Rule::applies_at`, with the biome looked up only for rules that test one. Rules with
+        // a custom name are not loaded.
+        if rule.faces & face.bit() == 0
+            || rule.heights.as_ref().is_some_and(|h| !h.contains(pos[1]))
+        {
+            return None;
+        }
+        if let Some(biomes) = &rule.biomes
+            && !biome().is_some_and(|b| biomes.matches(b))
+        {
+            return None;
+        }
+        let info = self.states.get(state as usize).copied().unwrap_or_default();
+        let joins = |offset: [i32; 3]| {
+            let other = neighbour(offset);
+            match rule.connect {
+                Connect::Block => {
+                    self.states.get(other as usize).map(|s| s.block) == Some(info.block)
+                }
+                Connect::State => other == state,
+                Connect::Tile => self
+                    .face_layers
+                    .get(other as usize)
+                    .is_some_and(|f| f[face as usize] == layer),
+            }
+        };
+        let axes = |face| match (rule.orient, info.axis) {
+            (Orient::StateAxis, Some(axis)) => Axes::column(face, axis),
+            // `orient=texture` follows the quad's own UVs; vanilla cubes are what it is used on.
+            _ => Axes::cube(face),
+        };
+        let mask = || geometry::neighbours(axes(face), face.normal(), rule.inner_seams, joins);
+        let tile = |i: usize| r.tiles.get(i).copied().unwrap_or(TileLayer::Default);
+        let index = match rule.method {
+            Method::Ctm => geometry::ctm_index(mask()),
+            Method::CtmCompact => {
+                let mask = mask();
+                let case = geometry::ctm_index(mask) as u8;
+                match rule.compact_overrides.iter().find(|&&(c, _)| c == case) {
+                    Some(&(_, t)) => t,
+                    None => {
+                        let quarters = geometry::compact_quarters(mask).map(|q| tile(q.into()));
+                        return if quarters.contains(&TileLayer::Skip) {
+                            None
+                        } else {
+                            Some(Pick::Quarters(quarters))
+                        };
+                    }
+                }
+            }
+            Method::Horizontal => geometry::horizontal(mask()),
+            Method::Vertical => geometry::vertical(mask()),
+            Method::HorizontalVertical => geometry::horizontal_vertical(mask()),
+            Method::VerticalHorizontal => geometry::vertical_horizontal(mask()),
+            Method::Top => {
+                // Only sides join the block above: the top and bottom go on to the next rule.
+                if matches!(face, Face::Up | Face::Down) {
+                    return None;
+                }
+                if !joins([0, 1, 0]) {
+                    return Some(Pick::Keep);
+                }
+                0
+            }
+            Method::Fixed => 0,
+            Method::Random => {
+                let face = geometry::symmetric_face(face, rule.symmetry);
+                let pos = if rule.linked && info.upper {
+                    [pos[0], pos[1] - 1, pos[2]]
+                } else {
+                    pos
+                };
+                geometry::random_index(pos, face, rule.random_loops, &rule.weights, r.tiles.len())
+            }
+            Method::Repeat => {
+                let face = geometry::symmetric_face(face, rule.symmetry);
+                geometry::repeat_index(pos, axes(face), rule.width, rule.height)
+            }
+            // Overlays are not loaded yet.
+            _ => return None,
+        };
+        match tile(index) {
+            TileLayer::Skip => None,
+            TileLayer::Default => Some(Pick::Keep),
+            t => Some(Pick::Tile(t)),
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use horizon_optifine::Properties;
+
+    /// A tile whose layer says which tile of its rule it is: rule `r`'s tile `i` is layer
+    /// `1000 * (r + 1) + i`.
+    fn rules(files: &[(&str, &str)]) -> Vec<LoadedRule> {
+        let mut rules: Vec<Rule> = files
+            .iter()
+            .map(|(path, text)| {
+                Rule::parse(
+                    &format!("assets/minecraft/optifine/ctm/{path}"),
+                    &Properties::parse(text),
+                )
+                .unwrap()
+                .unwrap()
+            })
+            .collect();
+        ctm::sort(&mut rules);
+        rules
+            .into_iter()
+            .enumerate()
+            .map(|(n, rule)| LoadedRule {
+                tiles: rule
+                    .tiles
+                    .iter()
+                    .enumerate()
+                    .map(|(i, t)| match t {
+                        Tile::Skip => TileLayer::Skip,
+                        Tile::Default => TileLayer::Default,
+                        Tile::Texture(_) => TileLayer::Layer {
+                            layer: (1000 * (n + 1) + i) as u16,
+                            translucent: false,
+                            opaque: false,
+                        },
+                    })
+                    .collect(),
+                rule,
+            })
+            .collect()
+    }
+
+    /// State 0 air, 1 glass, 2 stone, 3 and 4 oak logs (axis y, x), 5 and 6 a door (lower,
+    /// upper); the stone sprite is layer 7.
+    fn world(files: &[(&str, &str)]) -> ConnectedTextures {
+        let props = |pairs: &[(&str, &str)]| -> BlockProperties {
+            pairs
+                .iter()
+                .map(|(k, v)| (k.to_string(), v.to_string()))
+                .collect()
+        };
+        let states = [
+            ("minecraft:air", props(&[])),
+            ("minecraft:glass", props(&[])),
+            ("minecraft:stone", props(&[])),
+            ("minecraft:oak_log", props(&[("axis", "y")])),
+            ("minecraft:oak_log", props(&[("axis", "x")])),
+            ("minecraft:oak_door", props(&[("half", "lower")])),
+            ("minecraft:oak_door", props(&[("half", "upper")])),
+        ];
+        ConnectedTextures::build(
+            rules(files),
+            states.iter().map(|(n, p)| Some((*n, p))),
+            |name| (name == "minecraft:block/stone").then_some(7),
+        )
+    }
+
+    fn tile(layer: u16) -> Pick {
+        Pick::Tile(TileLayer::Layer {
+            layer,
+            translucent: false,
+            opaque: false,
+        })
+    }
+
+    /// `pick` on `face` of the block at the origin among `blocks` (offset, state).
+    fn pick_in(
+        ctm: &ConnectedTextures,
+        state: u32,
+        layer: u16,
+        face: Face,
+        blocks: &[([i32; 3], u32)],
+    ) -> Pick {
+        let at = |o: [i32; 3]| blocks.iter().find(|(p, _)| *p == o).map_or(0, |b| b.1);
+        ctm.pick(state, layer, face, [0, 64, 0], at, || None)
+    }
+
+    const GLASS: &str = "matchBlocks=glass\nmethod=ctm\ntiles=0-46";
+
+    #[test]
+    fn glass_joins_its_neighbours() {
+        let ctm = world(&[("glass.properties", GLASS)]);
+        // Alone: tile 0. A north face's right is west: glass there is the left end of a row.
+        assert_eq!(pick_in(&ctm, 1, 3, Face::North, &[]), tile(1000));
+        assert_eq!(
+            pick_in(&ctm, 1, 3, Face::North, &[([-1, 0, 0], 1)]),
+            tile(1001)
+        );
+        // Glass all around in the face's plane: the middle tile, 26.
+        let ring: Vec<_> = [-1, 0, 1]
+            .into_iter()
+            .flat_map(|x| [-1, 0, 1].map(|y| ([x, y, 0], 1)))
+            .collect();
+        assert_eq!(pick_in(&ctm, 1, 3, Face::North, &ring), tile(1026));
+        // Stone beside it doesn't join; stone has no rule.
+        assert_eq!(
+            pick_in(&ctm, 1, 3, Face::North, &[([-1, 0, 0], 2)]),
+            tile(1000)
+        );
+        assert_eq!(pick_in(&ctm, 2, 7, Face::North, &[]), Pick::Keep);
+    }
+
+    #[test]
+    fn rule_order_faces_and_skips() {
+        let ctm = world(&[
+            (
+                "a_sides.properties",
+                "matchBlocks=stone\nmethod=fixed\ntiles=<skip>\nfaces=sides",
+            ),
+            ("b_glass.properties", GLASS),
+            ("stone.properties", "method=fixed\ntiles=x\nfaces=top"),
+            ("z.properties", "matchBlocks=stone\nmethod=fixed\ntiles=y"),
+        ]);
+        // The tile rule (stone.properties, by its file name) comes first, on the top face only.
+        assert_eq!(pick_in(&ctm, 2, 7, Face::Up, &[]), tile(1000));
+        // Sides: a_sides skips, so z draws.
+        assert_eq!(pick_in(&ctm, 2, 7, Face::North, &[]), tile(4000));
+        // The tile rule follows the sprite, whatever the block: glass with the stone sprite.
+        assert_eq!(pick_in(&ctm, 1, 7, Face::Up, &[]), tile(1000));
+    }
+
+    #[test]
+    fn compact_quarters_and_overrides() {
+        let ctm = world(&[(
+            "glass.properties",
+            "matchBlocks=glass\nmethod=ctm_compact\ntiles=0-5\nctm.1=5",
+        )]);
+        let layer = |i: u16| TileLayer::Layer {
+            layer: 1000 + i,
+            translucent: false,
+            opaque: false,
+        };
+        assert_eq!(
+            pick_in(&ctm, 1, 3, Face::North, &[]),
+            Pick::Quarters([layer(0); 4])
+        );
+        // Joined right only is case 1, replaced whole by tile 5.
+        assert_eq!(
+            pick_in(&ctm, 1, 3, Face::North, &[([-1, 0, 0], 1)]),
+            tile(1005)
+        );
+        // Joined left only (east of a north face): quarters [3, 0, 3, 0].
+        assert_eq!(
+            pick_in(&ctm, 1, 3, Face::North, &[([1, 0, 0], 1)]),
+            Pick::Quarters([layer(3), layer(0), layer(3), layer(0)])
+        );
+    }
+
+    #[test]
+    fn logs_turn_with_their_axis() {
+        let ctm = world(&[(
+            "log.properties",
+            "matchBlocks=oak_log\nmethod=vertical\ntiles=0-3",
+        )]);
+        // An upright log with a log above: the bottom of a column.
+        assert_eq!(
+            pick_in(&ctm, 3, 3, Face::North, &[([0, 1, 0], 3)]),
+            tile(1000)
+        );
+        // A log lying along x: on its north face the texture's up points east, so a log to the
+        // east (same block, other axis state) is above it.
+        assert_eq!(
+            pick_in(&ctm, 4, 3, Face::North, &[([1, 0, 0], 4)]),
+            tile(1000)
+        );
+        assert_eq!(
+            pick_in(&ctm, 4, 3, Face::North, &[([0, 1, 0], 4)]),
+            tile(1003)
+        );
+    }
+
+    #[test]
+    fn top_and_connect_state() {
+        let ctm = world(&[(
+            "block_oak_log.properties",
+            "method=top\ntiles=0\nconnect=state",
+        )]);
+        assert_eq!(
+            pick_in(&ctm, 3, 3, Face::North, &[([0, 1, 0], 3)]),
+            tile(1000)
+        );
+        // The other axis is another state.
+        assert_eq!(
+            pick_in(&ctm, 3, 3, Face::North, &[([0, 1, 0], 4)]),
+            Pick::Keep
+        );
+        assert_eq!(pick_in(&ctm, 3, 3, Face::Up, &[([0, 1, 0], 3)]), Pick::Keep);
+    }
+
+    #[test]
+    fn linked_random_follows_the_lower_half() {
+        let ctm = world(&[(
+            "door.properties",
+            "matchBlocks=oak_door\nmethod=random\ntiles=0-7\nlinked=true",
+        )]);
+        let mut tiles = std::collections::HashSet::new();
+        for x in 0..20 {
+            let lower = ctm.pick(5, 3, Face::North, [x, 64, 0], |_| 0, || None);
+            let upper = ctm.pick(6, 3, Face::North, [x, 65, 0], |_| 0, || None);
+            assert_eq!(lower, upper, "{x}");
+            tiles.insert(format!("{lower:?}"));
+        }
+        assert!(tiles.len() > 3, "the doors are not all alike");
+    }
+
+    #[test]
+    fn heights_and_biomes() {
+        let ctm = world(&[(
+            "glass.properties",
+            "matchBlocks=glass\nmethod=fixed\ntiles=0\nheights=0-63\nbiomes=desert",
+        )]);
+        let at =
+            |y, biome: &'static str| ctm.pick(1, 3, Face::Up, [0, y, 0], |_| 0, || Some(biome));
+        assert_eq!(at(10, "minecraft:desert"), tile(1000));
+        assert_eq!(at(64, "minecraft:desert"), Pick::Keep);
+        assert_eq!(at(10, "minecraft:plains"), Pick::Keep);
+    }
+
+    #[test]
+    fn connect_by_tile_reads_the_neighbours_same_side() {
+        let mut ctm = world(&[(
+            "glass.properties",
+            "matchBlocks=glass\nmethod=horizontal\nconnect=tile\ntiles=0-3",
+        )]);
+        // Stone shows the glass sprite (3) on its north side; the door only on its south.
+        let mut faces = vec![[9u16; 6]; 7];
+        faces[1][Face::North as usize] = 3;
+        faces[2][Face::North as usize] = 3;
+        faces[5][Face::South as usize] = 3;
+        ctm.face_layers = faces;
+        assert_eq!(
+            pick_in(&ctm, 1, 3, Face::North, &[([-1, 0, 0], 2)]),
+            tile(1000)
+        );
+        assert_eq!(
+            pick_in(&ctm, 1, 3, Face::North, &[([-1, 0, 0], 5)]),
+            tile(1003)
+        );
+    }
+
+    #[test]
+    fn repeat_and_rows_then_columns() {
+        let ctm = world(&[(
+            "glass.properties",
+            "matchBlocks=glass\nmethod=repeat\nwidth=2\nheight=2\ntiles=0-3",
+        )]);
+        let at = |pos| ctm.pick(1, 3, Face::North, pos, |_| 0, || None);
+        assert_eq!(at([0, 64, 0]), tile(1000));
+        // The north face's right is west; rows run down.
+        assert_eq!(at([-1, 64, 0]), tile(1001));
+        assert_eq!(at([0, 63, 0]), tile(1002));
+        let hv = world(&[(
+            "glass.properties",
+            "matchBlocks=glass\nmethod=horizontal+vertical\ntiles=0-6",
+        )]);
+        // Alone in its row, glass above: the column's bottom, tile 4.
+        assert_eq!(
+            pick_in(&hv, 1, 3, Face::North, &[([0, 1, 0], 1)]),
+            tile(1004)
+        );
+        assert_eq!(
+            pick_in(&hv, 1, 3, Face::North, &[([-1, 0, 0], 1)]),
+            tile(1000)
+        );
+    }
+
+    #[test]
+    fn skips_defaults_and_narrowed_rules() {
+        let ctm = world(&[
+            (
+                "a.properties",
+                "matchBlocks=glass\nmethod=ctm_compact\ntiles=<skip> 1-4",
+            ),
+            (
+                "b.properties",
+                "matchBlocks=glass\nmethod=fixed\ntiles=0\nfaces=sides",
+            ),
+            (
+                "c.properties",
+                "matchBlocks=glass\nmethod=fixed\ntiles=<default>",
+            ),
+            ("d.properties", "matchBlocks=glass\nmethod=fixed\ntiles=0"),
+            (
+                "e.properties",
+                "matchBlocks=stone\nmatchTiles=glass_pane_top\nmethod=fixed\ntiles=0",
+            ),
+        ]);
+        // e names a tile, so it is tried first (tile 1000s), but needs a stone with the pane
+        // sprite. a's skipped quarter drops it; b (3000s) draws the sides; on top c draws the
+        // glass itself, which stops d.
+        assert_eq!(pick_in(&ctm, 1, 3, Face::North, &[]), tile(3000));
+        assert_eq!(pick_in(&ctm, 1, 3, Face::Up, &[]), Pick::Keep);
+        assert_eq!(pick_in(&ctm, 2, 7, Face::Up, &[]), Pick::Keep);
+        let both = world(&[(
+            "e.properties",
+            "matchBlocks=glass\nmatchTiles=stone\nmethod=fixed\ntiles=0",
+        )]);
+        assert_eq!(pick_in(&both, 1, 7, Face::Up, &[]), tile(1000));
+        assert_eq!(pick_in(&both, 1, 3, Face::Up, &[]), Pick::Keep);
+        assert_eq!(pick_in(&both, 2, 7, Face::Up, &[]), Pick::Keep);
+        // `top` passes the top face on.
+        let top = world(&[
+            ("block_glass.properties", "method=top\ntiles=0"),
+            (
+                "z.properties",
+                "matchBlocks=glass\nmethod=fixed\ntiles=0\nfaces=top",
+            ),
+        ]);
+        assert_eq!(pick_in(&top, 1, 3, Face::Up, &[]), tile(2000));
+    }
+
+    #[test]
+    fn sprite_names() {
+        assert_eq!(
+            sprite_name("assets/minecraft/textures/block/dirt.png"),
+            "minecraft:block/dirt"
+        );
+        assert_eq!(
+            sprite_name("assets/minecraft/optifine/ctm/glass/0.png"),
+            "assets/minecraft/optifine/ctm/glass/0.png"
+        );
+    }
+}

crates/horizon-client-render/src/crash.rs

@@ -195,6 +195,14 @@ fn read(path: &str) -> Option<String> {
     std::fs::read_to_string(path).ok()
 }
 
+fn windows_processor_name(query: &str) -> Option<String> {
+    query.lines().find_map(|line| {
+        let (_, value) = line.split_once("REG_SZ")?;
+        let value = value.trim();
+        (!value.is_empty()).then(|| value.to_owned())
+    })
+}
+
 /// `PRETTY_NAME` of /etc/os-release and the kernel, or the system's own version string.
 fn operating_system() -> String {
     let arch = std::env::consts::ARCH;
@@ -235,6 +243,18 @@ pub fn cpu() -> String {
         })
     } else if cfg!(target_os = "macos") {
         command_output("sysctl", &["-n", "machdep.cpu.brand_string"])
+    } else if cfg!(windows) {
+        command_output(
+            "reg",
+            &[
+                "query",
+                r"HKLM\HARDWARE\DESCRIPTION\System\CentralProcessor\0",
+                "/v",
+                "ProcessorNameString",
+            ],
+        )
+        .and_then(|query| windows_processor_name(&query))
+        .or_else(|| std::env::var("PROCESSOR_IDENTIFIER").ok())
     } else {
         std::env::var("PROCESSOR_IDENTIFIER").ok()
     };
@@ -354,7 +374,8 @@ fn deliver(home: &Path, report: Report) -> Option<PathBuf> {
     );
     crate::logging::flush();
     crate::telemetry::keep_crash(home, &report);
-    match report.save(home) {
+    // A player of a shared game folder (`--player-dir`) finds the report beside its own log.
+    match report.save(crate::logging::player_dir_override().unwrap_or(home)) {
         Ok(path) => {
             eprintln!("{SAVED_LINE}{}", path.display());
             Some(path)
@@ -386,6 +407,30 @@ pub fn report_watchdog(home: &Path, side: &'static str, message: String) -> Opti
     )
 }
 
+/// The report for a game that went over the player's RAM limit (`ram_limit`), written by the
+/// watcher thread: it says nothing about where the memory went, so it carries no stack. The player
+/// chose this limit, so it is no bug to send (`telemetry::keep_crash`), and leaving that out ends
+/// the game seconds sooner: it keeps running, over its limit, until the report is written.
+pub fn report_memory_limit(home: &Path, side: &'static str, message: String) {
+    if REPORTED.swap(true, Ordering::SeqCst) {
+        return;
+    }
+    let report = Report {
+        time: Local::now(),
+        description: "RAM limit reached".into(),
+        error: message,
+        stack: String::new(),
+        thread: thread_name(side),
+        side,
+        details: system_details(side),
+        log: crate::logging::recent_lines(),
+    };
+    match report.save(home) {
+        Ok(path) => eprintln!("{SAVED_LINE}{}", path.display()),
+        Err(e) => eprintln!("Horizon: could not save a crash report: {e}"),
+    }
+}
+
 fn payload_text(payload: &(dyn std::any::Any + Send)) -> String {
     payload
         .downcast_ref::<&str>()
@@ -636,6 +681,22 @@ pub fn debug_crash_after() -> Option<std::time::Duration> {
 mod tests {
     use super::*;
 
+    #[test]
+    fn windows_registry_cpu_name_is_read_without_the_registry_columns() {
+        let query = r#"
+HKEY_LOCAL_MACHINE\HARDWARE\DESCRIPTION\System\CentralProcessor\0
+    ProcessorNameString    REG_SZ    13th Gen Intel(R) Core(TM) i7-13700F
+"#;
+        assert_eq!(
+            windows_processor_name(query).as_deref(),
+            Some("13th Gen Intel(R) Core(TM) i7-13700F")
+        );
+        assert_eq!(
+            windows_processor_name("ProcessorNameString REG_SZ   "),
+            None
+        );
+    }
+
     #[test]
     fn a_release_reports_its_built_in_version() {
         // release.yml builds with HORIZON_VERSION (docs/versioning.md): `v0.2.3`, wherever it is installed.

crates/horizon-client-render/src/datapack.rs

@@ -575,7 +575,7 @@ pub struct DataStore {
     /// `item_modifier` files, for `/item modify`.
     pub item_modifiers: BTreeMap<String, serde_json::Value>,
     /// The content tables' raw files from the packs after the built-in one:
-    /// `recipe/`, `loot_table/`, `advancement/`, `dialog/` and `tags/…/` files, by
+    /// `recipe/`, `recipe_filter/`, `loot_table/`, `advancement/`, `dialog/` and `tags/…/` files, by
     /// `<kind-dir>/<ns>:<path>`, each id's files in pack order. The tables
     /// merge them over what they read from the resource root.
     pub files: BTreeMap<String, Vec<Vec<u8>>>,
@@ -583,7 +583,7 @@ pub struct DataStore {
     pub errors: Vec<(String, String)>,
 }
 /// `<kind-dir>/<ns>:<path>` for a pack file the content tables read:
-/// `recipe/`, `loot_table/`, `advancement/`, `trade_set/`,
+/// `recipe/`, `recipe_filter/`, `loot_table/`, `advancement/`, `trade_set/`,
 /// `villager_trade/`, `dialog/` or `tags/<sub>/`, where the id keeps the sub
 /// path so a nested tag kind stays addressable.
 fn content_id(file: &str) -> Option<String> {
@@ -591,7 +591,8 @@ fn content_id(file: &str) -> Option<String> {
     let (ns, rest) = rest.split_once('/')?;
     let (kind, rest) = rest.split_once('/')?;
     let kind = match kind {
-        "recipe" | "loot_table" | "advancement" | "trade_set" | "villager_trade" | "dialog" => kind,
+        "recipe" | "recipe_filter" | "loot_table" | "advancement" | "trade_set"
+        | "villager_trade" | "dialog" => kind,
         // A tag id is `{ns}:{path-under-tags}` (`tags/worldgen/biome/
         // test:sub/mytag`), the whole path after the namespace, so nested
         // registries keep their directory (`TagLoader`'s id shape).
@@ -628,6 +629,7 @@ impl DataStore {
                 "loot_table",
                 "predicate",
                 "recipe",
+                "recipe_filter",
                 "tags",
                 "trade_set",
                 "villager_trade",

crates/horizon-client-render/src/entity.wgsl

@@ -320,6 +320,13 @@ fn shadow_color(in: Out) -> vec4<f32> {
 }
 
 fn celestial_color(in: Out) -> vec4<f32> {
+    // RenderPipelines.DRAGON_RAYS / rendertype_lightning.fsh: untextured
+    // vertex colour, with fog fading both RGB and alpha before additive blending.
+    if in.overlay == 37u {
+        let fog = max(linear_fog(in.spherical, globals.fog.x, globals.fog.y),
+                      linear_fog(in.cylindrical, globals.fog.z, globals.fog.w));
+        return in.color * (1.0 - fog);
+    }
     return textureSample(atlas, atlas_sampler, in.uv) * in.color * in.light_color;
 }
 @fragment fn fs_celestial(in: Out) -> @location(0) vec4<f32> {

crates/horizon-client-render/src/environment.rs

@@ -141,6 +141,8 @@ pub struct Sky {
     pub fog_end: f32,
     /// `visual/cloud_fog_end_distance`.
     pub cloud_fog_end: f32,
+    /// `visual/cloud_height`.
+    pub cloud_height: f32,
 }
 impl Environment {
     pub fn load(root: &Path) -> Result<Self> {
@@ -309,6 +311,10 @@ impl Environment {
                 .base
                 .get("minecraft:visual/cloud_fog_end_distance")
                 .map_or(2048.0, |v| v[0]),
+            cloud_height: self
+                .base
+                .get("minecraft:visual/cloud_height")
+                .map_or(crate::clouds::CLOUD_HEIGHT as f32, |v| v[0]),
         }
     }
 }

crates/horizon-client-render/src/extras.rs

@@ -96,8 +96,13 @@ pub struct Extras {
     pub minimap_rotate: bool,
     /// Retry lost multiplayer connections (`reconnect`).
     pub auto_reconnect: bool,
+    /// Positional sounds leave a few static sound channels free for UI sounds
+    /// and others played to the listener (`sound_engine::HEARD_RESERVE`).
+    pub ui_sound_reserve: bool,
     /// The player's own name tag over its model in third person.
     pub own_name_tag: bool,
+    /// No particles from breaking or mining a block (other particles stay).
+    pub hide_block_particles: bool,
     /// Mouse Tweaks-style drags in the inventory and storage containers.
     pub mouse_tweaks: bool,
     /// With them, the wheel over a slot moves its items one at a time.
@@ -106,6 +111,10 @@ pub struct Extras {
     pub sort: bool,
     /// A vanilla key name: sorts the part under the cursor.
     pub sort_key: String,
+    /// A new chat line slides in from the left while it fades in (`Chat::layout`).
+    pub chat_animation: bool,
+    /// The indicator bar at the left of a chat line (on by default, as vanilla).
+    pub chat_indicator: bool,
     /// No AI: every AI feature hidden and off (`horizon_core::no_ai`; the launcher writes it too).
     pub no_ai: bool,
     /// Agents may control the game the player starts: it opens its control socket for
@@ -113,6 +122,8 @@ pub struct Extras {
     pub agent_control: bool,
     /// "Playing Horizon" on the player's Discord profile (`discord_presence`; on by default).
     pub discord_presence: bool,
+    /// Another controller can join P1's world (`splitscreen`, off by default).
+    pub splitscreen: bool,
 }
 impl Default for Extras {
     fn default() -> Self {
@@ -138,14 +149,19 @@ impl Default for Extras {
             minimap_zoom: 1.0,
             minimap_rotate: false,
             auto_reconnect: false,
+            ui_sound_reserve: false,
             own_name_tag: false,
+            hide_block_particles: false,
             mouse_tweaks: false,
             mouse_tweaks_wheel: true,
             sort: false,
             sort_key: "key.keyboard.unknown".into(),
+            chat_animation: false,
+            chat_indicator: true,
             no_ai: false,
             agent_control: false,
             discord_presence: true,
+            splitscreen: false,
         }
     }
 }
@@ -213,14 +229,19 @@ impl Extras {
                 }
                 "minimapRotate" => e.minimap_rotate = flag(e.minimap_rotate),
                 "autoReconnect" => e.auto_reconnect = flag(e.auto_reconnect),
+                "uiSoundReserve" => e.ui_sound_reserve = flag(e.ui_sound_reserve),
                 "ownNameTag" => e.own_name_tag = flag(e.own_name_tag),
+                "hideBlockParticles" => e.hide_block_particles = flag(e.hide_block_particles),
                 "mouseTweaks" => e.mouse_tweaks = flag(e.mouse_tweaks),
                 "mouseTweaksWheel" => e.mouse_tweaks_wheel = flag(e.mouse_tweaks_wheel),
                 "sort" => e.sort = flag(e.sort),
                 "sortKey" if value.starts_with("key.") => e.sort_key = value.to_owned(),
+                "chatAnimation" => e.chat_animation = flag(e.chat_animation),
+                "chatIndicator" => e.chat_indicator = flag(e.chat_indicator),
                 horizon_core::no_ai::KEY => e.no_ai = flag(e.no_ai),
                 "agentControl" => e.agent_control = flag(e.agent_control),
                 "discordPresence" => e.discord_presence = flag(e.discord_presence),
+                "splitscreen" => e.splitscreen = flag(e.splitscreen),
                 _ => {}
             }
         }
@@ -228,7 +249,7 @@ impl Extras {
     }
     pub fn serialize(&self) -> String {
         format!(
-            "fullbright:{}\ndynamicLights:{}\nzoom:{}\nzoomKey:{}\nzoomLevel:{}\nzoomSmooth:{}\nzoomSensitivity:{}\nfps:{}\nfpsCorner:{}\nfpsLows:{}\nkeystrokes:{}\nkeystrokesCorner:{}\nkeystrokesCps:{}\nmovedToMods:{}\nminimap:{}\nminimapCorner:{}\nminimapSize:{}\nminimapShape:{}\nminimapZoom:{}\nminimapRotate:{}\nautoReconnect:{}\nownNameTag:{}\nmouseTweaks:{}\nmouseTweaksWheel:{}\nsort:{}\nsortKey:{}\n{}:{}\nagentControl:{}\ndiscordPresence:{}\n",
+            "fullbright:{}\ndynamicLights:{}\nzoom:{}\nzoomKey:{}\nzoomLevel:{}\nzoomSmooth:{}\nzoomSensitivity:{}\nfps:{}\nfpsCorner:{}\nfpsLows:{}\nkeystrokes:{}\nkeystrokesCorner:{}\nkeystrokesCps:{}\nmovedToMods:{}\nminimap:{}\nminimapCorner:{}\nminimapSize:{}\nminimapShape:{}\nminimapZoom:{}\nminimapRotate:{}\nautoReconnect:{}\nuiSoundReserve:{}\nownNameTag:{}\nhideBlockParticles:{}\nmouseTweaks:{}\nmouseTweaksWheel:{}\nsort:{}\nsortKey:{}\nchatAnimation:{}\nchatIndicator:{}\n{}:{}\nagentControl:{}\ndiscordPresence:{}\nsplitscreen:{}\n",
             bool_text(self.fullbright),
             bool_text(self.dynamic_lights),
             bool_text(self.zoom),
@@ -254,15 +275,20 @@ impl Extras {
             self.minimap_zoom,
             bool_text(self.minimap_rotate),
             bool_text(self.auto_reconnect),
+            bool_text(self.ui_sound_reserve),
             bool_text(self.own_name_tag),
+            bool_text(self.hide_block_particles),
             bool_text(self.mouse_tweaks),
             bool_text(self.mouse_tweaks_wheel),
             bool_text(self.sort),
             self.sort_key,
+            bool_text(self.chat_animation),
+            bool_text(self.chat_indicator),
             horizon_core::no_ai::KEY,
             bool_text(self.no_ai),
             bool_text(self.agent_control),
             bool_text(self.discord_presence),
+            bool_text(self.splitscreen),
         )
     }
     /// Binds the extra key `name` (`SORT_KEY`); false for
@@ -383,16 +409,24 @@ pub enum Item {
     Fullbright,
     DynamicLights,
     OwnNameTag,
+    HideBlockParticles,
     AutoReconnect,
+    UiSoundReserve,
     MouseTweaks,
     MouseTweaksWheel,
     Sort,
     SortKey,
+    /// A new chat line slides in and fades in (`Chat::layout`).
+    ChatAnimation,
+    /// The coloured bar at the left of a chat line.
+    ChatIndicator,
     /// Not on the Extras page: Horizon Settings shows No AI, its AI Agent page Agent Control.
     NoAi,
     AgentControl,
     /// On the Horizon Settings page.
     DiscordPresence,
+    /// On the Splitscreen settings page.
+    Splitscreen,
 }
 /// The Extras page: headers and items.
 pub fn rows() -> Vec<Result<Item, &'static str>> {
@@ -403,13 +437,20 @@ pub fn rows() -> Vec<Result<Item, &'static str>> {
         Ok(DynamicLights),
         Err("Third person"),
         Ok(OwnNameTag),
+        Err("Particles"),
+        Ok(HideBlockParticles),
         Err("Inventory"),
         Ok(MouseTweaks),
         Ok(MouseTweaksWheel),
         Ok(Sort),
         Ok(SortKey),
+        Err("Chat"),
+        Ok(ChatAnimation),
+        Ok(ChatIndicator),
         Err("Multiplayer"),
         Ok(AutoReconnect),
+        Err("Sound"),
+        Ok(UiSoundReserve),
     ]
 }
 impl Item {
@@ -418,24 +459,32 @@ impl Item {
             Item::Fullbright => "Fullbright",
             Item::DynamicLights => "Dynamic lights",
             Item::OwnNameTag => "Own name tag",
+            Item::HideBlockParticles => "Hide block-break particles",
             Item::AutoReconnect => "Auto-reconnect",
+            Item::UiSoundReserve => "Keep channels for UI sounds",
             Item::MouseTweaks => "Mouse Tweaks controls",
             Item::MouseTweaksWheel => "Scroll wheel moves items",
             Item::Sort => "Sort buttons",
             Item::SortKey => "Sort key",
+            Item::ChatAnimation => "Smooth chat",
+            Item::ChatIndicator => "Message indicator",
             Item::NoAi => "No AI",
             Item::AgentControl => "Agent Control",
             Item::DiscordPresence => "Discord Rich Presence",
+            Item::Splitscreen => "Splitscreen",
         }
     }
     /// The switch this setting belongs to: it does nothing while that is off.
     pub fn parent(self) -> Option<Item> {
         use Item::*;
         Some(match self {
+            UiSoundReserve => return None,
             MouseTweaksWheel => MouseTweaks,
             SortKey => Sort,
-            Fullbright | DynamicLights | OwnNameTag | MouseTweaks | Sort | AutoReconnect | NoAi
-            | AgentControl | DiscordPresence => {
+            ChatIndicator => ChatAnimation,
+            Fullbright | DynamicLights | OwnNameTag | HideBlockParticles | MouseTweaks | Sort
+            | AutoReconnect | NoAi | AgentControl | DiscordPresence | Splitscreen
+            | ChatAnimation => {
                 return None;
             }
         })
@@ -450,9 +499,15 @@ impl Item {
             Item::OwnNameTag => {
                 "Shows your name above your head in third person, as other players see it. Hidden when the server hides your team's names or you're invisible."
             }
+            Item::HideBlockParticles => {
+                "Hides the debris particles that burst from a broken block and crumble off the one you mine. Other particles stay."
+            }
             Item::AutoReconnect => {
                 "Rejoins a server after a lost connection or a restart, never after a kick or ban."
             }
+            Item::UiSoundReserve => {
+                "Sounds in the world leave 16 of the 247 sound channels free, so a flood of them (a big explosion) can't silence menu clicks."
+            }
             Item::MouseTweaks => {
                 "Right-drag places one per slot, left-drag gathers the held item, Shift + left-drag moves every slot."
             }
@@ -465,12 +520,19 @@ impl Item {
             Item::SortKey => {
                 "Sorts the part under the cursor. Click, then press a key; Escape unbinds it."
             }
+            Item::ChatAnimation => {
+                "A new chat line slides in from the left while it fades in, instead of appearing whole."
+            }
+            Item::ChatIndicator => "The coloured bar at the left of a chat line.",
             Item::NoAi => {
                 "Hides and turns off every AI feature: agent control, horizon-ctl and the MCP servers. The launcher's switch too."
             }
             Item::DiscordPresence => {
                 "Shows Playing Horizon on your Discord profile while Discord runs: menus, single player or multiplayer, the dimension and the time played. Never a world's name or a server's address."
             }
+            Item::Splitscreen => {
+                "In a world, another controller can join as a new player: press A when it asks, then pick a profile and where to play."
+            }
             Item::AgentControl => {
                 "Your own AI agent can play this game through horizon-ctl or an MCP client, on this computer only."
             }
@@ -481,10 +543,15 @@ impl Item {
         use crate::graphics_style::Cost;
         match self {
             Item::Fullbright => Some(Cost::None),
+            Item::UiSoundReserve => Some(Cost::None),
             Item::DynamicLights => Some(Cost::Low),
-            Item::OwnNameTag | Item::AutoReconnect | Item::MouseTweaks | Item::Sort => {
-                Some(Cost::None)
-            }
+            Item::ChatAnimation => Some(Cost::None),
+            Item::OwnNameTag
+            | Item::HideBlockParticles
+            | Item::AutoReconnect
+            | Item::MouseTweaks
+            | Item::Sort
+            | Item::Splitscreen => Some(Cost::None),
             _ => None,
         }
     }
@@ -494,13 +561,18 @@ impl Item {
             Item::Fullbright => e.fullbright,
             Item::DynamicLights => e.dynamic_lights,
             Item::OwnNameTag => e.own_name_tag,
+            Item::HideBlockParticles => e.hide_block_particles,
             Item::AutoReconnect => e.auto_reconnect,
+            Item::UiSoundReserve => e.ui_sound_reserve,
             Item::MouseTweaks => e.mouse_tweaks,
             Item::MouseTweaksWheel => e.mouse_tweaks_wheel,
             Item::Sort => e.sort,
+            Item::ChatAnimation => e.chat_animation,
+            Item::ChatIndicator => e.chat_indicator,
             Item::NoAi => e.no_ai,
             Item::AgentControl => e.agent_control,
             Item::DiscordPresence => e.discord_presence,
+            Item::Splitscreen => e.splitscreen,
             _ => return None,
         })
     }
@@ -521,13 +593,18 @@ impl Item {
             Item::Fullbright => e.fullbright = !e.fullbright,
             Item::DynamicLights => e.dynamic_lights = !e.dynamic_lights,
             Item::OwnNameTag => e.own_name_tag = !e.own_name_tag,
+            Item::HideBlockParticles => e.hide_block_particles = !e.hide_block_particles,
             Item::AutoReconnect => e.auto_reconnect = !e.auto_reconnect,
+            Item::UiSoundReserve => e.ui_sound_reserve = !e.ui_sound_reserve,
             Item::MouseTweaks => e.mouse_tweaks = !e.mouse_tweaks,
             Item::MouseTweaksWheel => e.mouse_tweaks_wheel = !e.mouse_tweaks_wheel,
             Item::Sort => e.sort = !e.sort,
+            Item::ChatAnimation => e.chat_animation = !e.chat_animation,
+            Item::ChatIndicator => e.chat_indicator = !e.chat_indicator,
             Item::NoAi => e.no_ai = !e.no_ai,
             Item::AgentControl => e.agent_control = !e.agent_control,
             Item::DiscordPresence => e.discord_presence = !e.discord_presence,
+            Item::Splitscreen => e.splitscreen = !e.splitscreen,
             Item::SortKey => {}
         }
     }
@@ -549,7 +626,8 @@ mod tests {
         let d = Extras::default();
         assert!(!d.fullbright && !d.dynamic_lights);
         assert!(!d.zoom && !d.fps && !d.keystrokes && !d.minimap && !d.auto_reconnect);
-        assert!(!d.mouse_tweaks && !d.sort && !d.own_name_tag);
+        assert!(!d.mouse_tweaks && !d.sort && !d.own_name_tag && !d.ui_sound_reserve);
+        assert!(!d.hide_block_particles);
         assert!(d.discord_presence);
         assert_eq!(Extras::parse(""), d);
         assert_eq!(Extras::parse(&d.serialize()), d);
@@ -575,11 +653,22 @@ mod tests {
         e.auto_reconnect = true;
         Item::OwnNameTag.cycle(&mut e, false);
         assert_eq!(Item::OwnNameTag.switch(&e), Some(true));
+        assert_eq!(Item::HideBlockParticles.switch(&e), Some(false));
+        Item::HideBlockParticles.cycle(&mut e, false);
+        assert!(e.hide_block_particles);
+        assert_eq!(Item::HideBlockParticles.switch(&e), Some(true));
+        let only = Extras::parse("hideBlockParticles:true\n");
+        assert!(only.hide_block_particles && !only.own_name_tag);
         e.mouse_tweaks = true;
         e.mouse_tweaks_wheel = false;
         e.sort = true;
         e.sort_key = "key.keyboard.r".into();
+        e.chat_animation = true;
+        e.chat_indicator = false;
         e.discord_presence = false;
+        assert!(!e.splitscreen);
+        Item::Splitscreen.cycle(&mut e, false);
+        assert_eq!(Item::Splitscreen.switch(&e), Some(true));
         assert_eq!(Extras::parse(&e.serialize()), e);
     }
 

crates/horizon-client-render/src/font.rs

@@ -112,6 +112,8 @@ struct Region {
     cursor: (u32, u32),
     row: u32,
     pending: Vec<Patch>,
+    /// A glyph did not fit since the last `Font::begin_frame`.
+    full: bool,
 }
 struct Cache {
     /// Every font by id, the default one first (the common lookup).
@@ -546,6 +548,7 @@ impl Region {
             self.row = 0;
         }
         if y + h > region.1 {
+            self.full = true;
             return None;
         }
         let (ax, ay) = (x, region.0 + y);
@@ -603,6 +606,7 @@ impl Font {
                     cursor: (0, 0),
                     row: 0,
                     pending: Vec::new(),
+                    full: false,
                 },
                 random: horizon_core::random::LegacyRandom::new(
                     std::time::SystemTime::now()
@@ -669,8 +673,19 @@ impl Font {
         }
         cache.region.cursor = (0, 0);
         cache.region.row = 0;
+        cache.region.full = false;
         self.generation.set(next_generation());
     }
+    /// Call once per frame before any text is laid out. When the dynamic
+    /// region ran out of room (vanilla's glyph textures grow instead), the
+    /// glyphs are forgotten so they are rasterized again from the start; it
+    /// waits for the frame boundary because quads already queued hold the old
+    /// rects.
+    pub fn begin_frame(&self) {
+        if self.cache.borrow().region.full {
+            self.reset_cache();
+        }
+    }
     /// Changes whenever a glyph may come out different: another font, a
     /// cache reset (glyphs move in the atlas) or other font options. Text laid
     /// out under one epoch can be kept until it changes.
@@ -706,7 +721,16 @@ impl Font {
         if let Some(g) = set.glyphs.get(&c) {
             return *g;
         }
-        let glyph = self.resolve(set, region, c).unwrap_or(self.missing);
+        let was_full = std::mem::replace(&mut region.full, false);
+        let found = self.resolve(set, region, c);
+        // No room: the missing glyph for now, not remembered, so the
+        // character is tried again once `begin_frame` cleared the region.
+        let overflowed = std::mem::replace(&mut region.full, was_full);
+        region.full |= overflowed;
+        if overflowed {
+            return self.missing;
+        }
+        let glyph = found.unwrap_or(self.missing);
         set.glyphs.insert(c, glyph);
         glyph
     }
@@ -1418,4 +1442,56 @@ mod tests {
         font.reset_cache();
         assert_eq!(font.glyph('a').advance, 2.0);
     }
+
+    #[test]
+    fn a_full_glyph_region_recovers_at_the_next_frame() {
+        // Two 8x8 glyphs from a sheet outside the atlas; the region holds one row.
+        let sheet = png(16, 8, |x, _| x % 8 < 4);
+        let default = br#"{"providers":[{"type":"bitmap","file":"pack:font/s.png","ascent":7,"chars":["ab"]}]}"#;
+        let root = root(
+            "full",
+            &[
+                ("assets/minecraft/font/default.json", default),
+                ("assets/pack/textures/font/s.png", &sheet),
+            ],
+        );
+        // A 10 wide atlas fits one 8 pixel glyph per row; the region two rows.
+        let font = Font::load(&root, &HashMap::new(), &[], (10, 64), (0, 8), white());
+        let _ = std::fs::remove_dir_all(&root);
+        let epoch = font.epoch();
+        let a = font.glyph('a');
+        assert!(a.rect.is_some());
+        // No room for 'b': missing for now, and asked again next time.
+        assert!(font.glyph('b').rect.is_none());
+        assert!(font.glyph('b').rect.is_none());
+        assert_eq!(font.epoch(), epoch);
+        font.begin_frame();
+        assert_ne!(font.epoch(), epoch);
+        let b = font.glyph('b');
+        assert!(b.rect.is_some());
+        assert_eq!(b.advance, a.advance);
+        // Nothing overflowed since: the next frame keeps the glyphs.
+        let epoch = font.epoch();
+        font.begin_frame();
+        assert_eq!(font.epoch(), epoch);
+    }
+
+    #[test]
+    fn a_character_without_a_provider_does_not_reset_the_region() {
+        let sheet = png(8, 8, |x, _| x < 4);
+        let default = br#"{"providers":[{"type":"bitmap","file":"pack:font/s.png","ascent":7,"chars":["a"]}]}"#;
+        let root = root(
+            "nofill",
+            &[
+                ("assets/minecraft/font/default.json", default),
+                ("assets/pack/textures/font/s.png", &sheet),
+            ],
+        );
+        let font = Font::load(&root, &HashMap::new(), &[], (10, 64), (0, 8), white());
+        let _ = std::fs::remove_dir_all(&root);
+        let epoch = font.epoch();
+        assert!(font.glyph('z').rect.is_none());
+        font.begin_frame();
+        assert_eq!(font.epoch(), epoch);
+    }
 }

crates/horizon-client-render/src/gfx/animate.rs

@@ -299,6 +299,7 @@ impl SpriteAnimator {
         uploads: &mut Uploads,
         tick: u64,
         active: Option<&[u64]>,
+        timing: Option<&mut super::pack_timing::PassTiming>,
     ) {
         if self.collect(tick, active) == 0 {
             return;
@@ -341,7 +342,7 @@ impl SpriteAnimator {
         }
         let mut pass = encoder.begin_compute_pass(&wgpu::ComputePassDescriptor {
             label: Some("Animated sprites"),
-            timestamp_writes: None,
+            timestamp_writes: timing.and_then(|t| t.compute_writes("Animated sprites")),
         });
         pass.set_pipeline(pipeline);
         for group in &mut self.groups {
@@ -859,7 +860,7 @@ mod tests {
         for tick in [0, 0, 1, 2, 3, 4, 7, 7, 12, 30] {
             let mut encoder = device.create_command_encoder(&Default::default());
             let shown: Vec<_> = animator.sprites.iter().map(|s| s.shown).collect();
-            animator.animate(&mut encoder, &mut uploads, tick, None);
+            animator.animate(&mut encoder, &mut uploads, tick, None, None);
             writes.push(
                 animator
                     .sprites

crates/horizon-client-render/src/gfx/arena.rs

@@ -1,12 +1,21 @@
 //! One vertex buffer for every terrain section: sections own ranges of it, so
 //! a frame binds it once and draws every section with indirect multi-draw.
+//! Translucent quads can have an arena of their own (`Arena::translucent`),
+//! with pages up to `LARGE_PAGE_BYTES`, and their sorted indices too
+//! (`Arena::translucent_indices`): their back-to-front list then stays in one
+//! page of each and draws in a few multi-draws.
 use std::collections::BTreeMap;
 
 /// Ranges are rounded up to this many vertices to limit fragmentation, and
 /// start at multiples of it (`flat` names sections by these blocks).
 pub const GRAIN: u64 = 256;
-/// The largest page, in bytes.
+/// The largest page of the section arena, and of arenas shaders bind whole
+/// as storage, in bytes.
 pub const PAGE_BYTES: u64 = 256 << 20;
+/// The largest page of an arena no shader binds as storage: under 2 GiB, where
+/// DirectX 12 and OpenGL cap buffers (`i32::MAX`), with room for the bytes
+/// wgpu-core adds to vertex buffers; the device's own limit still applies.
+pub const LARGE_PAGE_BYTES: u64 = (1 << 31) - (1 << 20);
 
 /// Free vertex ranges: start -> length, never adjacent.
 #[derive(Debug, PartialEq)]
@@ -118,7 +127,7 @@ impl Arena {
         } else {
             wgpu::BufferUsages::VERTEX
         };
-        Self::with_usage(device, stride, capacity, usage)
+        Self::with_usage(device, stride, capacity, usage, PAGE_BYTES)
     }
     /// Sorted translucent indices; `storage` when compute passes read them.
     pub fn indices(device: &wgpu::Device, capacity: u64, storage: bool) -> Self {
@@ -127,16 +136,54 @@ impl Arena {
         } else {
             wgpu::BufferUsages::INDEX
         };
-        Self::with_usage(device, 4, capacity, usage)
+        Self::with_usage(device, 4, capacity, usage, PAGE_BYTES)
+    }
+    /// Translucent quads' vertices, which no shader reads as storage: pages
+    /// up to `LARGE_PAGE_BYTES`. The section arena's compaction never runs on
+    /// it (`Renderer::compact_arena`): a page this large has no others to
+    /// empty into, and the compaction moves sections' `page` ranges, not their
+    /// `translucent_at`.
+    pub fn translucent(device: &wgpu::Device, stride: u64, capacity: u64) -> Self {
+        let usage = wgpu::BufferUsages::VERTEX;
+        Self::with_usage(device, stride, capacity, usage, LARGE_PAGE_BYTES)
+    }
+    /// Sorted indices of the translucent arena's quads: pages up to
+    /// `LARGE_PAGE_BYTES` as its own, so its draws keep to one index page too.
+    pub fn translucent_indices(device: &wgpu::Device, capacity: u64) -> Self {
+        let usage = wgpu::BufferUsages::INDEX;
+        Self::with_usage(device, 4, capacity, usage, LARGE_PAGE_BYTES)
+    }
+    /// The sorted-index arena and, when `split`, the translucent arena
+    /// (vertices of `stride`), both with large pages, which no shader binds;
+    /// otherwise translucent quads stay in the section arena, and the indices
+    /// in pages flat draws (`flat`) bind as storage.
+    pub fn translucent_arenas(
+        device: &wgpu::Device,
+        stride: u64,
+        flat: bool,
+        split: bool,
+    ) -> (Self, Option<Self>) {
+        if split {
+            let indices = Self::translucent_indices(device, 1 << 16);
+            (indices, Some(Self::translucent(device, stride, 1 << 18)))
+        } else {
+            (Self::indices(device, 1 << 16, flat), None)
+        }
     }
     fn with_usage(
         device: &wgpu::Device,
         stride: u64,
         capacity: u64,
         usage: wgpu::BufferUsages,
+        page_bytes: u64,
     ) -> Self {
-        // 256 MiB pages, or less where the device's buffers are smaller.
-        let bytes = device.limits().max_buffer_size.min(PAGE_BYTES);
+        // Pages of `page_bytes`, or less where the device's buffers (or the
+        // storage bindings that read them whole) are smaller.
+        let limits = device.limits();
+        let mut bytes = limits.max_buffer_size.min(page_bytes);
+        if usage.contains(wgpu::BufferUsages::STORAGE) {
+            bytes = bytes.min(limits.max_storage_buffer_binding_size);
+        }
         let page_limit = (bytes / stride) / GRAIN * GRAIN;
         let capacity = capacity.next_multiple_of(GRAIN).min(page_limit);
         Self {
@@ -151,11 +198,16 @@ impl Arena {
             video_memory_full: false,
         }
     }
-    /// A buffer of `capacity` vertices in video memory or, when that is full
-    /// and the device allows it, in system memory: Vulkan drivers fail an
-    /// allocation rather than page like OpenGL ones, and wgpu's default error
-    /// handler panics. `None` when neither has room.
-    fn create(&mut self, device: &wgpu::Device, capacity: u64) -> Option<(wgpu::Buffer, bool)> {
+    /// A buffer of `capacity` vertices in video memory or, when that is full,
+    /// `spill` allows it and so does the device, in system memory: Vulkan
+    /// drivers fail an allocation rather than page like OpenGL ones, and
+    /// wgpu's default error handler panics. `None` when neither has room.
+    fn create(
+        &mut self,
+        device: &wgpu::Device,
+        capacity: u64,
+        spill: bool,
+    ) -> Option<(wgpu::Buffer, bool)> {
         let usage = self.usage | wgpu::BufferUsages::COPY_DST | wgpu::BufferUsages::COPY_SRC;
         #[cfg(test)]
         let local = (!self.video_memory_full)
@@ -167,9 +219,10 @@ impl Arena {
         local.or_else(|| {
             // Mappable buffers are placed in host-visible memory, which the
             // allocator takes from system memory once video memory is full.
-            if !device
-                .features()
-                .contains(wgpu::Features::MAPPABLE_PRIMARY_BUFFERS)
+            if !spill
+                || !device
+                    .features()
+                    .contains(wgpu::Features::MAPPABLE_PRIMARY_BUFFERS)
             {
                 return None;
             }
@@ -234,7 +287,7 @@ impl Arena {
             && self.closing != Some(last as u32)
         {
             let current = page.capacity;
-            let grown = (current * 2).max(current + len).min(self.page_limit);
+            let grown = self.grown(current, len);
             if (grown - current >= len || grown == self.page_limit)
                 && self.grow(device, encoder, last, grown)
                 && let Some(start) = self.pages[last].as_mut().unwrap().free.take(len)
@@ -250,9 +303,9 @@ impl Arena {
         .max(len)
         .min(self.page_limit);
         // A page just large enough when memory is short.
-        let ((buffer, host), capacity) = match self.create(device, capacity) {
+        let ((buffer, host), capacity) = match self.create(device, capacity, true) {
             Some(buffer) => (buffer, capacity),
-            None if capacity > len => (self.create(device, len)?, len),
+            None if capacity > len => (self.create(device, len, true)?, len),
             None => return None,
         };
         let mut free = FreeList::new(capacity);
@@ -392,8 +445,17 @@ impl Arena {
             }
         }
     }
+    /// The capacity the newest page grows to for a range of `len`: double, but
+    /// by at most `PAGE_BYTES` past that size, so a large page is never left
+    /// half empty (nor held twice during the copy) by hundreds of MiB.
+    fn grown(&self, current: u64, len: u64) -> u64 {
+        let step = current.min(PAGE_BYTES / self.stride);
+        (current + step).max(current + len).min(self.page_limit)
+    }
     /// Moves a page into a larger buffer; false (the page unchanged) when
-    /// there is no memory for it.
+    /// there is no memory for it. A page past `PAGE_BYTES` grows in video
+    /// memory only: moving all of it to system memory would slow every frame
+    /// that draws it, so a new page takes the range instead (and may spill).
     fn grow(
         &mut self,
         device: &wgpu::Device,
@@ -402,7 +464,8 @@ impl Arena {
         capacity: u64,
     ) -> bool {
         let capacity = capacity.next_multiple_of(GRAIN).min(self.page_limit);
-        let Some((buffer, host)) = self.create(device, capacity) else {
+        let spill = capacity * self.stride <= PAGE_BYTES;
+        let Some((buffer, host)) = self.create(device, capacity, spill) else {
             return false;
         };
         let old = self.pages[page].as_mut().expect("live arena page");
@@ -474,6 +537,26 @@ mod tests {
         .ok()
     }
 
+    /// A device with the adapter's own limits, as the renderer opens it: page
+    /// caps past the default 256 MiB buffer limit show there.
+    fn device_at_limits() -> Option<(wgpu::Device, wgpu::Queue)> {
+        let instance = wgpu::Instance::new(wgpu::InstanceDescriptor::new_without_display_handle());
+        let adapter = pollster::block_on(instance.request_adapter(&Default::default())).ok()?;
+        pollster::block_on(adapter.request_device(&wgpu::DeviceDescriptor {
+            required_limits: adapter.limits(),
+            ..Default::default()
+        }))
+        .ok()
+    }
+
+    /// `device` and `device_at_limits`: the default limits bind 128 MiB of a storage
+    /// buffer, half their 256 MiB buffers, so storage pages shrink to the binding there;
+    /// the adapter's own let large pages past 256 MiB.
+    fn devices() -> Vec<(wgpu::Device, wgpu::Queue)> {
+        let devices = [device(), device_at_limits()];
+        devices.into_iter().flatten().collect()
+    }
+
     /// `Arena::alloc`, with the copies of a grow submitted at once.
     fn alloc(
         arena: &mut Arena,
@@ -588,6 +671,119 @@ mod tests {
         }
     }
 
+    /// The renderer's half of that compaction (`move_off_page`) moves what each
+    /// section holds in the section arena, data and all. Split, that is its
+    /// solid quads alone, and nothing of a section without any, whose (0, 0)
+    /// names no range of page 0; else solid and translucent quads together,
+    /// `translucent_at` along.
+    #[test]
+    fn compaction_moves_what_sections_hold_in_the_section_arena() {
+        use super::super::{SectionGpu, move_off_page};
+        let Some((device, queue)) = device() else {
+            eprintln!("no GPU adapter: skipped");
+            return;
+        };
+        let stride = std::mem::size_of::<crate::mesher::TerrainVertex>() as u64;
+        let section = |(page, start), translucent_at, solid, translucent| SectionGpu {
+            page,
+            start,
+            translucent_at,
+            solid,
+            sides: crate::mesher::Sides::unsorted(solid),
+            translucent,
+            sort: super::super::translucency::SortState::new(Vec::new()),
+            sorted_indices: None,
+            flat_id: None,
+            fading: None,
+            leaving: None,
+            animated_layers: Box::new([]),
+        };
+        for split in [true, false] {
+            let mut arena = Arena::new(&device, stride, 4 * GRAIN, false);
+            arena.page_limit = 4 * GRAIN;
+            // Page 0: two sections' grains and two free ones; page 1: one taken.
+            let (_, a) = alloc(&mut arena, &device, &queue, GRAIN).unwrap();
+            let (_, b) = alloc(&mut arena, &device, &queue, GRAIN).unwrap();
+            let (_, rest) = alloc(&mut arena, &device, &queue, 2 * GRAIN).unwrap();
+            assert_eq!(alloc(&mut arena, &device, &queue, GRAIN), Some((1, 0)));
+            arena.release(0, rest, 2 * GRAIN);
+            // Split, a grain of solid quads each (the first's translucent ones, and
+            // all of a water section's, in the translucent arena); else a grain of
+            // solid and translucent quads, and one of translucent quads alone.
+            let mut sections = if split {
+                vec![
+                    section((0, a), (0, 0), 64, 64),
+                    section((0, 0), (0, GRAIN), 0, 64),
+                    section((0, b), (0, 0), 64, 0),
+                ]
+            } else {
+                vec![
+                    section((0, a), (0, a + 128), 32, 32),
+                    section((0, b), (0, b), 0, 64),
+                ]
+            };
+            // A range's first and last vertex hold its section's number, and the
+            // first translucent one of a mixed range that plus 100.
+            let write = |(page, at): (u32, u64), value: usize| {
+                let bytes = (value as u32).to_le_bytes();
+                queue.write_buffer(arena.buffer(page), at * stride, &bytes);
+            };
+            for (i, s) in sections.iter().enumerate() {
+                if let Some((page, start, len)) = s.vertex_ranges(split).0 {
+                    write((page, start), i);
+                    write((page, start + len - 1), i);
+                    if !split && s.solid > 0 && s.translucent > 0 {
+                        write(s.translucent_at, 100 + i);
+                    }
+                }
+            }
+            let before: Vec<_> = sections
+                .iter()
+                .map(|s| (s.page, s.start, s.translucent_at))
+                .collect();
+            arena.close(0);
+            let mut encoder = device.create_command_encoder(&Default::default());
+            let meshes = sections.iter_mut();
+            assert!(move_off_page(
+                &mut arena,
+                &mut encoder,
+                None,
+                meshes,
+                0,
+                split,
+                u64::MAX
+            ));
+            queue.submit([encoder.finish()]);
+            let word =
+                |(page, at): (u32, u64)| read(&device, &queue, arena.buffer(page), at * stride);
+            for (i, s) in sections.iter().enumerate() {
+                let Some((page, start, len)) = s.vertex_ranges(split).0 else {
+                    assert_eq!(
+                        (s.page, s.start, s.translucent_at),
+                        before[i],
+                        "split {split}"
+                    );
+                    continue;
+                };
+                assert_eq!(page, 1, "split {split}");
+                assert_eq!(word((page, start)), i as u32);
+                assert_eq!(word((page, start + len - 1)), i as u32);
+                if !split {
+                    assert_eq!(s.translucent_at, (page, start + u64::from(s.solid) * 4));
+                    if s.solid > 0 {
+                        assert_eq!(word(s.translucent_at), 100 + i as u32);
+                    }
+                }
+            }
+            // Page 0 empties without a range given twice, and page 1 took a grain
+            // per section moved: one is left.
+            arena.trim();
+            assert!(!arena.has_page(0), "split {split}");
+            assert!(arena.alloc_existing(GRAIN).is_some(), "split {split}");
+            assert_eq!(arena.alloc_existing(GRAIN), None, "split {split}");
+        }
+    }
+
     #[test]
     fn empty_pages_are_reclaimed_without_moving_live_ranges() {
         let Some((device, queue)) = device() else {
@@ -630,6 +826,96 @@ mod tests {
         assert!(arena.pages.is_empty());
     }
 
+    /// Every arena's pages stay within its cap and the device's limits: the
+    /// whole-page storage bindings of flat draws and shader packs included.
+    #[test]
+    fn pages_stay_within_their_caps_and_the_device_limits() {
+        let devices = devices();
+        if devices.is_empty() {
+            eprintln!("no GPU adapter: skipped");
+            return;
+        }
+        let bytes = |a: &Arena| a.page_vertices() * a.stride;
+        for (device, _) in &devices {
+            let limits = device.limits();
+            for storage in [false, true] {
+                for arena in [
+                    Arena::new(device, 24, GRAIN, storage),
+                    Arena::indices(device, GRAIN, storage),
+                ] {
+                    assert!(bytes(&arena) <= PAGE_BYTES.min(limits.max_buffer_size));
+                    let binding = limits.max_storage_buffer_binding_size;
+                    assert!(!storage || bytes(&arena) <= binding);
+                }
+            }
+            for large in [
+                Arena::translucent(device, 24, GRAIN),
+                Arena::translucent_indices(device, GRAIN),
+            ] {
+                assert!(bytes(&large) <= LARGE_PAGE_BYTES.min(limits.max_buffer_size));
+                assert!(!large.usage.contains(wgpu::BufferUsages::STORAGE));
+            }
+        }
+    }
+
+    /// The translucent arena comes with the split layout alone, and only then
+    /// are the index pages large. Otherwise, as while a shader pack's terrain
+    /// draws flat (gfx's `translucent_split`), translucent quads keep to the
+    /// section arena, and flat draws (`flat`) bind the index pages as storage.
+    #[test]
+    fn translucent_arenas_follow_the_layout() {
+        let devices = devices();
+        if devices.is_empty() {
+            eprintln!("no GPU adapter: skipped");
+            return;
+        }
+        let mut exercised = false;
+        for (device, _) in &devices {
+            let limits = device.limits();
+            let large = limits.max_buffer_size > PAGE_BYTES;
+            exercised |= large;
+            for flat in [false, true] {
+                for split in [false, true] {
+                    let case = format!("large {large}, flat {flat}, split {split}");
+                    let (indices, translucent) = Arena::translucent_arenas(device, 24, flat, split);
+                    assert_eq!(translucent.is_some(), split, "{case}");
+                    let bytes = indices.page_vertices() * 4;
+                    let storage = indices.usage.contains(wgpu::BufferUsages::STORAGE);
+                    assert_eq!(storage, flat && !split, "{case}");
+                    assert!(!storage || bytes <= limits.max_storage_buffer_binding_size);
+                    assert_eq!(bytes > PAGE_BYTES, split && large, "{case}");
+                    if let Some(t) = translucent {
+                        assert_eq!(t.page_vertices() * 24 > PAGE_BYTES, large, "{case}");
+                    }
+                }
+            }
+        }
+        if !exercised {
+            eprintln!("buffers end at PAGE_BYTES here: large pages not exercised");
+        }
+    }
+
+    /// Pages double up to `PAGE_BYTES`, then grow by `PAGE_BYTES` at most.
+    #[test]
+    fn large_pages_grow_by_bounded_steps() {
+        let Some((device, _)) = device() else {
+            eprintln!("no GPU adapter: skipped");
+            return;
+        };
+        let mut arena = Arena::translucent(&device, 24, GRAIN);
+        // Exercise the policy past the test device's own buffer limit.
+        arena.page_limit = LARGE_PAGE_BYTES / 24 / GRAIN * GRAIN;
+        let step = PAGE_BYTES / 24;
+        assert_eq!(arena.grown(1 << 18, GRAIN), 1 << 19);
+        assert_eq!(arena.grown(step, GRAIN), 2 * step);
+        assert_eq!(arena.grown(3 * step, GRAIN), 4 * step);
+        assert_eq!(arena.grown(3 * step, step + GRAIN), 4 * step + GRAIN);
+        assert_eq!(
+            arena.grown(arena.page_limit - GRAIN, GRAIN),
+            arena.page_limit
+        );
+    }
+
     #[test]
     fn clearing_an_arena_releases_buffers_and_can_allocate_again() {
         let Some((device, queue)) = device() else {
@@ -638,7 +924,9 @@ mod tests {
         };
         for mut arena in [
             Arena::new(&device, 28, GRAIN, false),
+            Arena::translucent(&device, 24, GRAIN),
             Arena::indices(&device, GRAIN, false),
+            Arena::translucent_indices(&device, GRAIN),
         ] {
             alloc(&mut arena, &device, &queue, GRAIN).unwrap();
             assert_eq!(arena.bytes(), arena.stride * GRAIN);

crates/horizon-client-render/src/gfx/cull.rs

@@ -528,7 +528,11 @@ impl Cull {
 
     /// Between the phases (`InShader`): draw the tested boxes in a pass of
     /// their own that reads phase 1's depth, bound by `bind_depth`.
-    pub fn test_pass(&self, encoder: &mut wgpu::CommandEncoder) {
+    pub fn test_pass(
+        &self,
+        encoder: &mut wgpu::CommandEncoder,
+        timing: Option<&mut super::pack_timing::PassTiming>,
+    ) {
         let (Some(Group { group, .. }), Some(DepthGroup { view, group: depth })) =
             (&self.group, &self.depth_group)
         else {
@@ -539,6 +543,7 @@ impl Cull {
         }
         let mut pass = encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
             label: Some("Section culling"),
+            timestamp_writes: timing.and_then(|t| t.writes("Occlusion test")),
             color_attachments: &[],
             depth_stencil_attachment: Some(wgpu::RenderPassDepthStencilAttachment {
                 view,
@@ -580,23 +585,25 @@ impl Cull {
         self.current = Some(self.next);
     }
 
-    /// After the frame's submission: start reading its results back.
-    pub fn submitted(&mut self) {
-        let Some(i) = self.current.take() else {
-            return;
-        };
+    /// The frame's results to read back, started by calling it right after the frame's
+    /// submission (on the submit thread, when the frame goes there).
+    pub fn submitted(&mut self) -> Option<impl FnOnce() + Send + 'static> {
+        let i = self.current.take()?;
         let r = &self.readbacks[i];
         let state = r.state.clone();
         state.store(PENDING, Ordering::Release);
-        r.buffer
-            .slice(..r.slots.len() as u64 * 4)
-            .map_async(wgpu::MapMode::Read, move |result| {
-                state.store(
-                    if result.is_ok() { MAPPED } else { FREE },
-                    Ordering::Release,
-                );
-            });
+        let (buffer, bytes) = (r.buffer.clone(), r.slots.len() as u64 * 4);
         self.next = (i + 1) % READBACKS;
+        Some(move || {
+            buffer
+                .slice(..bytes)
+                .map_async(wgpu::MapMode::Read, move |result| {
+                    state.store(
+                        if result.is_ok() { MAPPED } else { FREE },
+                        Ordering::Release,
+                    );
+                });
+        })
     }
 
     fn make_group(

crates/horizon-client-render/src/gfx/entity_batch.rs

@@ -20,6 +20,8 @@ const MATERIALS: usize = 10;
 /// (`RenderTypes.entityTranslucent`, `entityTranslucentEmissive`, `eyes`,
 /// `breezeWind`). Only the improved transparency path reads it.
 pub const OIT_ENTITY: u32 = 1 << 24;
+/// `RenderPipelines.DRAGON_RAYS`: untextured colour, additive with depth writes.
+pub const DRAGON_RAYS_OVERLAY: u32 = 37;
 /// Tags quads as drawn by a render type vanilla gives an `OitPipelineSet`
 /// (`OIT_ENTITY`): improved transparency draws them in its stages.
 pub fn mark_oit(quads: &mut [Vertex]) {

crates/horizon-client-render/src/gfx/entity_outline.rs

@@ -258,13 +258,20 @@ impl EntityOutline {
         frame: &wgpu::TextureView,
         entity_group: &wgpu::BindGroup,
         indices: &wgpu::Buffer,
+        mut timing: Option<&mut super::pack_timing::PassTiming>,
     ) {
         let Some(t) = self.targets.as_ref().filter(|_| self.quads > 0) else {
             return;
         };
         let clear = wgpu::LoadOp::Clear(wgpu::Color::TRANSPARENT);
         {
-            let mut pass = begin(encoder, "Entity outline", &t.outline, clear);
+            let mut pass = begin(
+                encoder,
+                "Entity outline",
+                &t.outline,
+                clear,
+                timing.as_deref_mut(),
+            );
             pass.set_pipeline(&self.silhouette);
             pass.set_bind_group(0, entity_group, &[]);
             pass.set_index_buffer(indices.slice(..), wgpu::IndexFormat::Uint32);
@@ -280,7 +287,7 @@ impl EntityOutline {
             ("Entity outline blit", frame, wgpu::LoadOp::Load),
         ];
         for (i, (label, view, load)) in steps.into_iter().enumerate() {
-            let mut pass = begin(encoder, label, view, load);
+            let mut pass = begin(encoder, label, view, load, timing.as_deref_mut());
             pass.set_pipeline(&self.passes[i]);
             pass.set_bind_group(0, &t.groups[i], &[]);
             pass.draw(0..3, 0..1);
@@ -293,6 +300,7 @@ fn begin<'e>(
     label: &str,
     view: &wgpu::TextureView,
     load: wgpu::LoadOp<wgpu::Color>,
+    timing: Option<&mut super::pack_timing::PassTiming>,
 ) -> wgpu::RenderPass<'e> {
     let attachments = [Some(wgpu::RenderPassColorAttachment {
         view,
@@ -305,6 +313,7 @@ fn begin<'e>(
     })];
     encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
         label: Some(label),
+        timestamp_writes: timing.and_then(|t| t.writes(label)),
         color_attachments: &attachments,
         ..Default::default()
     })

crates/horizon-client-render/src/gfx/flat.rs

@@ -62,7 +62,13 @@ pub struct Call {
 }
 
 pub struct Flat {
+    /// The solid draws in one pass (`fs_solid`), where the GPU doesn't hide pixels
+    /// by tiles (`split_solid` in `Renderer::draw_frame`: elsewhere than Metal).
     pub solid: wgpu::RenderPipeline,
+    /// The solid draws in two passes over the same draws (terrain.wgsl's `opaque_quad`):
+    /// the quads with no cutout first, through a shader that never discards, then the rest.
+    pub solid_opaque: wgpu::RenderPipeline,
+    pub solid_cutout: wgpu::RenderPipeline,
     /// The solid draws as the water mirror's camera draws them (`fs_solid_mirror`).
     pub solid_mirror: wgpu::RenderPipeline,
     pub translucent: wgpu::RenderPipeline,
@@ -286,7 +292,7 @@ fn plan(
 }
 
 impl Flat {
-    /// `pipeline(layout, label, fragment entry, blend, cull)` builds a
+    /// `pipeline(layout, label, vertex entry, fragment entry, blend, cull)` builds a
     /// terrain pipeline as the per-section ones, without the origin buffer.
     pub fn new(
         device: &wgpu::Device,
@@ -297,6 +303,7 @@ impl Flat {
             &wgpu::PipelineLayout,
             &str,
             &str,
+            &str,
             Option<wgpu::BlendState>,
             Option<wgpu::Face>,
         ) -> wgpu::RenderPipeline,
@@ -354,11 +361,35 @@ impl Flat {
         let storage_usage = wgpu::BufferUsages::STORAGE;
         let back = Some(wgpu::Face::Back);
         Self {
-            solid: pipeline(&layout, "Terrain solid (flat)", "fs_solid", None, back),
+            solid: pipeline(
+                &layout,
+                "Terrain solid (flat)",
+                "vs_terrain_flat",
+                "fs_solid",
+                None,
+                back,
+            ),
+            solid_opaque: pipeline(
+                &layout,
+                "Terrain solid opaque (flat)",
+                "vs_terrain_flat_opaque",
+                "fs_opaque",
+                None,
+                back,
+            ),
+            solid_cutout: pipeline(
+                &layout,
+                "Terrain solid cutout (flat)",
+                "vs_terrain_flat_cutout",
+                "fs_solid",
+                None,
+                back,
+            ),
             // The mirror flips the winding: its solid terrain culls the front.
             solid_mirror: pipeline(
                 &layout,
                 "Terrain solid mirrored (flat)",
+                "vs_terrain_flat",
                 "fs_solid_mirror",
                 None,
                 Some(wgpu::Face::Front),
@@ -366,6 +397,7 @@ impl Flat {
             translucent: pipeline(
                 &layout,
                 "Terrain translucent (flat)",
+                "vs_terrain_flat",
                 "fs_translucent",
                 Some(wgpu::BlendState::ALPHA_BLENDING),
                 back,
@@ -490,6 +522,7 @@ impl Flat {
         phase2: Option<&wgpu::Buffer>,
         origins: impl Iterator<Item = (u32, [f32; 4])>,
         sorted_page: impl Fn(u32) -> wgpu::Buffer,
+        timing: Option<&mut super::pack_timing::PassTiming>,
     ) -> bool {
         self.phase2_group = None;
         let phase1_draws = if phase2.is_some() {
@@ -668,7 +701,7 @@ impl Flat {
             .collect();
         let mut pass = encoder.begin_compute_pass(&wgpu::ComputePassDescriptor {
             label: Some("Flatten section draws"),
-            timestamp_writes: None,
+            timestamp_writes: timing.and_then(|t| t.compute_writes("Flatten")),
         });
         pass.set_pipeline(&self.flatten);
         for (group, count) in &groups {
@@ -700,13 +733,17 @@ impl Flat {
         true
     }
     /// After occlusion culling's test: copies the phase 2 draws it saw.
-    pub fn flatten_phase2(&self, encoder: &mut wgpu::CommandEncoder) {
+    pub fn flatten_phase2(
+        &self,
+        encoder: &mut wgpu::CommandEncoder,
+        timing: Option<&mut super::pack_timing::PassTiming>,
+    ) {
         let Some((group, count)) = &self.phase2_group else {
             return;
         };
         let mut pass = encoder.begin_compute_pass(&wgpu::ComputePassDescriptor {
             label: Some("Flatten phase 2 section draws"),
-            timestamp_writes: None,
+            timestamp_writes: timing.and_then(|t| t.compute_writes("Flatten phase 2")),
         });
         pass.set_pipeline(&self.flatten_seen);
         pass.set_bind_group(0, group, &[]);

crates/horizon-client-render/src/gfx/frame_gen.rs

@@ -1,9 +1,11 @@
 //! Frame generation: FSR 3.1's frame interpolation will show a frame halfway between each
-//! two real ones. So far this holds its optical flow and interpolation; the setting that
-//! runs them comes next.
+//! two real ones. So far this holds its optical flow, its interpolation and the motion
+//! vectors of what moves on its own; the setting that runs them comes next.
 
 // Unused until the renderer runs them.
 #[allow(dead_code)]
 mod interpolation;
 #[allow(dead_code)]
+mod motion;
+#[allow(dead_code)]
 mod optical_flow;

crates/horizon-client-render/src/gfx/frame_gen/interpolation.rs

@@ -10,8 +10,8 @@
 //! priorities and vectors) and fill the game field's holes from a pyramid; mask what each
 //! frame can't see; blend the two frames along both fields; fill what is left from a
 //! pyramid of the result. What differs from AMD's, all forced by WGSL or by Horizon:
-//! the game's motion vectors are computed from the depth and `Inputs::reproject` (the
-//! camera's, so what moves on its own relies on the optical flow); textures AMD updates
+//! the game's motion vectors are the camera's, from the depth and `Inputs::reproject`,
+//! except where `Inputs::object_motion` has an entity's own; textures AMD updates
 //! with image atomics are storage buffers; SPD's single-pass pyramids are a pass per
 //! level; and there is no HUD-less pass, as Horizon draws its HUD over the made frame.
 
@@ -33,6 +33,9 @@ pub struct Inputs<'a> {
     /// `world_post::reprojection`): the motion vectors are the camera's, from this and
     /// the depth.
     pub reproject: Mat4,
+    /// What moved on its own: `motion::FORMAT` at `render_size`, xy its motion vector
+    /// (FSR's convention, in UV) where z is 1, used over the camera's.
+    pub object_motion: &'a wgpu::TextureView,
     pub near: f32,
     pub far: f32,
     /// Vertical field of view, radians.
@@ -442,6 +445,7 @@ impl Interpolation {
             &[
                 (0, params()),
                 (2, view(inputs.depth)),
+                (34, view(inputs.object_motion)),
                 (5, view(&r.dilated_depth)),
                 (6, view(&r.dilated_mv)),
                 (9, whole(&r.rec_prev_depth)),
@@ -644,10 +648,12 @@ mod tests {
     /// Runs `frames` (pattern shifts) through the optical flow and the interpolation with
     /// a camera that moves by `reproject` each frame, and returns the mean error of the
     /// last made frame's interior against `expected`, and the last two real frames'.
+    /// `object`: every pixel's own motion vector (UV), as if all of it moved on its own.
     fn interpolate(
         seed: u32,
         shifts: &[[i32; 2]],
         reproject: Mat4,
+        object: Option<[f32; 2]>,
         expected: [i32; 2],
     ) -> Option<[f32; 3]> {
         let (device, queue) = of::device()?;
@@ -682,6 +688,35 @@ mod tests {
             ..Default::default()
         });
         queue.submit([encoder.finish()]);
+        let object_motion = device.create_texture(&wgpu::TextureDescriptor {
+            label: None,
+            size: wgpu::Extent3d {
+                width: size[0],
+                height: size[1],
+                depth_or_array_layers: 1,
+            },
+            mip_level_count: 1,
+            sample_count: 1,
+            dimension: wgpu::TextureDimension::D2,
+            format: super::super::motion::FORMAT,
+            usage: wgpu::TextureUsages::TEXTURE_BINDING | wgpu::TextureUsages::COPY_DST,
+            view_formats: &[],
+        });
+        if let Some(mv) = object {
+            let texel = [mv[0], mv[1], 1.0, 0.0].map(|v| half::f16::from_f32(v).to_bits());
+            let texels: Vec<u16> = (0..size[0] * size[1]).flat_map(|_| texel).collect();
+            queue.write_texture(
+                object_motion.as_image_copy(),
+                bytemuck::cast_slice(&texels),
+                wgpu::TexelCopyBufferLayout {
+                    offset: 0,
+                    bytes_per_row: Some(size[0] * 8),
+                    rows_per_image: None,
+                },
+                object_motion.size(),
+            );
+        }
+        let object_motion = object_motion.create_view(&Default::default());
         let mut flow = OpticalFlow::new(&device, size);
         let mut interpolation = Interpolation::new(&device, size);
         let frames: Vec<_> = shifts
@@ -731,6 +766,7 @@ mod tests {
                     render_size: size,
                     jitter: [0.0; 2],
                     reproject: if i == 0 { Mat4::IDENTITY } else { reproject },
+                    object_motion: &object_motion,
                     near: 0.05,
                     far: 512.0,
                     fov_y: 1.2,
@@ -776,7 +812,8 @@ mod tests {
     fn moves_what_the_optical_flow_follows_halfway() {
         let mut shifts = vec![[0, 0]; 20];
         shifts.push([16, 8]);
-        let Some([made, previous, current]) = interpolate(100, &shifts, Mat4::IDENTITY, [8, 4])
+        let Some([made, previous, current]) =
+            interpolate(100, &shifts, Mat4::IDENTITY, None, [8, 4])
         else {
             return;
         };
@@ -795,7 +832,26 @@ mod tests {
         // What is at a pixel now was 16 pixels to its right last frame.
         let reproject = Mat4::from_translation(glam::Vec3::new(32.0 / size[0], 0.0, 0.0));
         let shifts = [[0, 0], [-16, 0], [-32, 0], [-48, 0]];
-        let Some([made, previous, current]) = interpolate(1, &shifts, reproject, [-40, 0]) else {
+        let Some([made, previous, current]) = interpolate(1, &shifts, reproject, None, [-40, 0])
+        else {
+            return;
+        };
+        assert!(
+            made * 4.0 < previous.min(current),
+            "{made} against {previous} and {current}"
+        );
+    }
+
+    /// Something moving on its own with its own motion vectors (the camera still): the
+    /// made frame is halfway, as with the camera's.
+    #[test]
+    fn moves_what_has_its_own_motion_vectors_halfway() {
+        let size = [512.0, 288.0];
+        let shifts = [[0, 0], [16, 8], [32, 16], [48, 24]];
+        let mv = [-16.0 / size[0], -8.0 / size[1]];
+        let Some([made, previous, current]) =
+            interpolate(1, &shifts, Mat4::IDENTITY, Some(mv), [40, 20])
+        else {
             return;
         };
         assert!(

crates/horizon-client-render/src/gfx/frame_gen/interpolation.wgsl

@@ -24,7 +24,8 @@
 // for Horizon, for an SDR back buffer, inverted finite depth, the whole screen as the
 // interpolation rect and no distortion field. What differs from AMD's (interpolation.rs
 // lists why):
-// - the motion vectors come from the depth and the camera (`prepare`), already unjittered;
+// - the motion vectors are the camera's, from the depth (`prepare`), already unjittered,
+//   or an entity's own where `object_motion` has one;
 // - the vector fields and reconstructed depths are storage buffers of atomics;
 // - both inpainting pyramids are a pass per level, and textures of their own;
 // - the interpolation writes one texture and the inpainting another (rgba16float can't
@@ -85,6 +86,8 @@ struct Params {
 @group(0) @binding(31) var interpolated_out: texture_storage_2d<rgba16float, write>;
 @group(0) @binding(32) var interpolated: texture_2d<f32>;
 @group(0) @binding(33) var output: texture_storage_2d<rgba16float, write>;
+// What moved on its own (motion.wgsl): xy its motion vector where z is 1.
+@group(0) @binding(34) var object_motion: texture_2d<f32>;
 
 const EPSILON: f32 = 1e-03;
 const RECONSTRUCTED_DEPTH_WEIGHT_THRESHOLD: f32 = EPSILON;
@@ -355,7 +358,11 @@ fn prepare_pass(@builtin(global_invocation_id) gid: vec3<u32>) {
             }
         }
     }
-    let mv = camera_motion_vector(nearest_coord, load_input_depth(nearest_coord));
+    let object = textureLoad(object_motion, nearest_coord, 0);
+    var mv = camera_motion_vector(nearest_coord, load_input_depth(nearest_coord));
+    if object.z > 0.5 {
+        mv = object.xy;
+    }
     textureStore(dilated_depth_out, p, vec4(nearest, 0.0, 0.0, 0.0));
     textureStore(dilated_mv_out, p, vec4(mv, 0.0, 0.0));
     // ReconstructPrevDepth

crates/horizon-client-render/src/gfx/frame_gen/motion.rs

@@ -0,0 +1,306 @@
+//! Motion vectors for what moves on its own, for frame generation: the camera's motion
+//! vectors (from the depth) see mobs and dropped items as still. The game tags each
+//! entity's vertices with its id (`Frame::entity_motion`); an entity whose vertices have
+//! the same shape as last frame's (the same count, UVs and layers) gets each vertex's
+//! own motion, limbs and spin included, drawn into a texture at the render size
+//! (`motion.wgsl`) that the interpolation reads before the camera's.
+
+use crate::mesher::Vertex;
+use glam::{DVec3, Mat4, Vec3};
+use std::collections::HashMap;
+
+/// `motion.wgsl`'s `Params`.
+#[repr(C)]
+#[derive(Clone, Copy, bytemuck::Pod, bytemuck::Zeroable)]
+struct Params {
+    jittered: [[f32; 4]; 4],
+    current: [[f32; 4]; 4],
+    previous: [[f32; 4]; 4],
+}
+
+/// A vertex this frame and where it was last frame, both relative to this frame's camera.
+#[repr(C)]
+#[derive(Clone, Copy, bytemuck::Pod, bytemuck::Zeroable)]
+struct MotionVertex {
+    position: [f32; 3],
+    previous: [f32; 3],
+    uv: [f32; 2],
+    /// 1 for a translucent item, whose texture says where it shows.
+    translucent: u32,
+}
+
+pub struct ObjectMotion {
+    pipeline: wgpu::RenderPipeline,
+    atlas: wgpu::TextureView,
+    sampler: wgpu::Sampler,
+    params: wgpu::Buffer,
+    vertices: wgpu::Buffer,
+    /// Triangles of the entities matched this frame.
+    staged: Vec<MotionVertex>,
+    /// Last frame's vertices by entity, and its camera.
+    tracked: HashMap<u64, Vec<Vertex>>,
+    camera: DVec3,
+    target: Option<([u32; 2], wgpu::TextureView)>,
+}
+
+pub const FORMAT: wgpu::TextureFormat = wgpu::TextureFormat::Rgba16Float;
+
+impl ObjectMotion {
+    /// `atlas`: the entities' texture atlas.
+    pub fn new(device: &wgpu::Device, atlas: wgpu::TextureView) -> Self {
+        let module = device.create_shader_module(wgpu::ShaderModuleDescriptor {
+            label: Some("Frame generation motion"),
+            source: wgpu::ShaderSource::Wgsl(include_str!("motion.wgsl").into()),
+        });
+        let attributes =
+            wgpu::vertex_attr_array![0 => Float32x3, 1 => Float32x3, 2 => Float32x2, 3 => Uint32];
+        let pipeline = device.create_render_pipeline(&wgpu::RenderPipelineDescriptor {
+            label: Some("Frame generation motion"),
+            layout: None,
+            vertex: wgpu::VertexState {
+                module: &module,
+                entry_point: Some("vs_motion"),
+                compilation_options: Default::default(),
+                buffers: &[Some(wgpu::VertexBufferLayout {
+                    array_stride: std::mem::size_of::<MotionVertex>() as u64,
+                    step_mode: wgpu::VertexStepMode::Vertex,
+                    attributes: &attributes,
+                })],
+            },
+            primitive: Default::default(),
+            depth_stencil: None,
+            multisample: Default::default(),
+            fragment: Some(wgpu::FragmentState {
+                module: &module,
+                entry_point: Some("fs_motion"),
+                compilation_options: Default::default(),
+                targets: &[Some(FORMAT.into())],
+            }),
+            multiview_mask: None,
+            cache: None,
+        });
+        Self {
+            pipeline,
+            atlas,
+            sampler: device.create_sampler(&Default::default()),
+            params: device.create_buffer(&wgpu::BufferDescriptor {
+                label: Some("Frame generation motion"),
+                size: std::mem::size_of::<Params>() as u64,
+                usage: wgpu::BufferUsages::UNIFORM | wgpu::BufferUsages::COPY_DST,
+                mapped_at_creation: false,
+            }),
+            vertices: vertex_buffer(device, 1 << 12),
+            staged: Vec::new(),
+            tracked: HashMap::new(),
+            camera: DVec3::ZERO,
+            target: None,
+        }
+    }
+
+    /// Forget last frame's entities: the next frame has no motion of its own.
+    pub fn reset(&mut self) {
+        self.tracked.clear();
+    }
+
+    /// Match this frame's `entities` (relative to `camera`) to last frame's by the ids
+    /// `spans` gives their vertices (start, id; 0 for none, each up to the next start), and
+    /// keep them for the next frame.
+    pub fn track(&mut self, entities: &[Vertex], spans: &[(u32, u64)], camera: DVec3) {
+        self.staged.clear();
+        let shift = (self.camera - camera).as_vec3();
+        let mut tracked = HashMap::with_capacity(self.tracked.len());
+        for (i, &(start, id)) in spans.iter().enumerate() {
+            let end = spans.get(i + 1).map_or(entities.len(), |s| s.0 as usize);
+            let Some(now) = entities
+                .get(start as usize..end)
+                .filter(|v| id != 0 && !v.is_empty())
+            else {
+                continue;
+            };
+            if let Some(then) = self.tracked.remove(&id)
+                && then.len() == now.len()
+                && then
+                    .iter()
+                    .zip(now)
+                    .all(|(a, b)| a.uv == b.uv && a.layer == b.layer)
+            {
+                let pair = |i: usize| MotionVertex {
+                    position: now[i].pos,
+                    previous: (Vec3::from(then[i].pos) + shift).into(),
+                    uv: now[i].uv,
+                    translucent: u32::from(matches!(
+                        now[i].layer,
+                        super::super::entity_batch::TRANSLUCENT_ITEM_OVERLAY
+                            | super::super::entity_batch::TRANSLUCENT_GLINT_ITEM_OVERLAY
+                    )),
+                };
+                for q in (0..now.len() / 4).map(|q| q * 4) {
+                    self.staged
+                        .extend([q, q + 1, q + 2, q, q + 2, q + 3].map(pair));
+                }
+            }
+            tracked.insert(id, now.to_vec());
+        }
+        self.tracked = tracked;
+        self.camera = camera;
+    }
+
+    /// Draw the matched entities' motion vectors at `size` (the world's render size),
+    /// where `depth` (the world's) shows them; the rest of the texture is 0.
+    #[allow(clippy::too_many_arguments)]
+    pub fn draw(
+        &mut self,
+        device: &wgpu::Device,
+        queue: &wgpu::Queue,
+        encoder: &mut wgpu::CommandEncoder,
+        depth: &wgpu::TextureView,
+        size: [u32; 2],
+        jittered: Mat4,
+        current: Mat4,
+        previous: Mat4,
+    ) -> wgpu::TextureView {
+        if self.target.as_ref().is_none_or(|t| t.0 != size) {
+            let texture = device.create_texture(&wgpu::TextureDescriptor {
+                label: Some("Frame generation motion"),
+                size: wgpu::Extent3d {
+                    width: size[0],
+                    height: size[1],
+                    depth_or_array_layers: 1,
+                },
+                mip_level_count: 1,
+                sample_count: 1,
+                dimension: wgpu::TextureDimension::D2,
+                format: FORMAT,
+                usage: wgpu::TextureUsages::RENDER_ATTACHMENT
+                    | wgpu::TextureUsages::TEXTURE_BINDING
+                    | wgpu::TextureUsages::COPY_SRC,
+                view_formats: &[],
+            });
+            self.target = Some((size, texture.create_view(&Default::default())));
+        }
+        let target = self.target.as_ref().expect("made above").1.clone();
+        let bytes: &[u8] = bytemuck::cast_slice(&self.staged);
+        if bytes.len() as u64 > self.vertices.size() {
+            self.vertices = vertex_buffer(device, (bytes.len() as u64).next_power_of_two());
+        }
+        if !bytes.is_empty() {
+            queue.write_buffer(&self.vertices, 0, bytes);
+        }
+        let params = Params {
+            jittered: jittered.to_cols_array_2d(),
+            current: current.to_cols_array_2d(),
+            previous: previous.to_cols_array_2d(),
+        };
+        queue.write_buffer(&self.params, 0, bytemuck::bytes_of(&params));
+        let group = device.create_bind_group(&wgpu::BindGroupDescriptor {
+            label: Some("Frame generation motion"),
+            layout: &self.pipeline.get_bind_group_layout(0),
+            entries: &[
+                wgpu::BindGroupEntry {
+                    binding: 0,
+                    resource: self.params.as_entire_binding(),
+                },
+                wgpu::BindGroupEntry {
+                    binding: 1,
+                    resource: wgpu::BindingResource::TextureView(depth),
+                },
+                wgpu::BindGroupEntry {
+                    binding: 2,
+                    resource: wgpu::BindingResource::TextureView(&self.atlas),
+                },
+                wgpu::BindGroupEntry {
+                    binding: 3,
+                    resource: wgpu::BindingResource::Sampler(&self.sampler),
+                },
+            ],
+        });
+        let attachments = [Some(wgpu::RenderPassColorAttachment {
+            view: &target,
+            resolve_target: None,
+            depth_slice: None,
+            ops: wgpu::Operations {
+                load: wgpu::LoadOp::Clear(wgpu::Color::TRANSPARENT),
+                store: wgpu::StoreOp::Store,
+            },
+        })];
+        let mut pass = encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
+            label: Some("Frame generation motion"),
+            color_attachments: &attachments,
+            ..Default::default()
+        });
+        if !self.staged.is_empty() {
+            pass.set_pipeline(&self.pipeline);
+            pass.set_bind_group(0, &group, &[]);
+            pass.set_vertex_buffer(0, self.vertices.slice(..bytes.len() as u64));
+            pass.draw(0..self.staged.len() as u32, 0..1);
+        }
+        drop(pass);
+        target
+    }
+}
+
+fn vertex_buffer(device: &wgpu::Device, size: u64) -> wgpu::Buffer {
+    device.create_buffer(&wgpu::BufferDescriptor {
+        label: Some("Frame generation motion vertices"),
+        size,
+        usage: wgpu::BufferUsages::VERTEX | wgpu::BufferUsages::COPY_DST,
+        mapped_at_creation: false,
+    })
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn shader_validates() {
+        let module = naga::front::wgsl::parse_str(include_str!("motion.wgsl")).unwrap();
+        naga::valid::Validator::new(
+            naga::valid::ValidationFlags::all(),
+            naga::valid::Capabilities::empty(),
+        )
+        .validate(&module)
+        .unwrap();
+    }
+
+    fn quad(x: f32, uv: f32) -> Vec<Vertex> {
+        (0..4)
+            .map(|i| Vertex {
+                pos: [x + i as f32, 0.0, -5.0],
+                uv: [uv, 0.0],
+                ..bytemuck::Zeroable::zeroed()
+            })
+            .collect()
+    }
+
+    /// An entity seen last frame gets its vertices' own motion, in this frame's camera
+    /// space; a new one, one whose shape changed and untagged geometry get none.
+    #[test]
+    fn tracks_each_entity_by_id() {
+        let Some((device, queue)) = super::super::optical_flow::tests::device() else {
+            return;
+        };
+        let atlas = super::super::optical_flow::tests::upload(&device, &queue, [1, 1], &[0; 4]);
+        let mut motion = ObjectMotion::new(&device, atlas);
+        let mut entities = quad(0.0, 0.0);
+        entities.extend(quad(10.0, 0.5));
+        motion.track(&entities, &[(0, 7), (4, 8)], DVec3::ZERO);
+        assert!(motion.staged.is_empty());
+        // Entity 7 moved 1 block right, the camera 2 blocks right; entity 8 became
+        // another item; 9 is new; then untagged geometry.
+        let mut entities = quad(-1.0, 0.0);
+        entities.extend(quad(10.0, 0.25));
+        entities.extend(quad(20.0, 0.0));
+        entities.extend(quad(30.0, 0.0));
+        motion.track(
+            &entities,
+            &[(0, 7), (4, 8), (8, 9), (12, 0)],
+            DVec3::new(2.0, 0.0, 0.0),
+        );
+        assert_eq!(motion.staged.len(), 6);
+        let v = motion.staged[0];
+        assert_eq!(v.position, [-1.0, 0.0, -5.0]);
+        assert_eq!(v.previous, [-2.0, 0.0, -5.0]);
+        assert_eq!(motion.tracked.len(), 3);
+    }
+}

crates/horizon-client-render/src/gfx/frame_gen/motion.wgsl

@@ -0,0 +1,58 @@
+// Frame generation's motion vectors for what moves on its own (mobs, dropped items): each
+// vertex drawn where the world pass drew it, with where it was last frame; only the pixels
+// the world shows it at keep its vector: where the depth is its own, or, for translucent
+// items (which don't write depth), where its texture shows and nothing is in front.
+
+struct Params {
+    // The world's projection this frame (TAA's jitter in it), the same without the jitter,
+    // and last frame's projection from this frame's camera.
+    jittered: mat4x4<f32>,
+    current: mat4x4<f32>,
+    previous: mat4x4<f32>,
+};
+
+@group(0) @binding(0) var<uniform> params: Params;
+@group(0) @binding(1) var depth: texture_depth_2d;
+@group(0) @binding(2) var atlas: texture_2d<f32>;
+@group(0) @binding(3) var atlas_sampler: sampler;
+
+struct Out {
+    @builtin(position) clip: vec4<f32>,
+    @location(0) current: vec4<f32>,
+    @location(1) previous: vec4<f32>,
+    @location(2) uv: vec2<f32>,
+    // 1: a translucent item.
+    @location(3) @interpolate(flat) translucent: u32,
+};
+
+@vertex fn vs_motion(@location(0) position: vec3<f32>, @location(1) previous: vec3<f32>,
+    @location(2) uv: vec2<f32>, @location(3) translucent: u32) -> Out {
+    var out: Out;
+    out.uv = uv;
+    out.translucent = translucent;
+    out.clip = params.jittered * vec4(position, 1.0);
+    out.current = params.current * vec4(position, 1.0);
+    out.previous = params.previous * vec4(previous, 1.0);
+    return out;
+}
+
+// xy: the motion vector in UV (to where the pixel was last frame, FSR's convention), z: 1.
+@fragment fn fs_motion(in: Out) -> @location(0) vec4<f32> {
+    let stored = textureLoad(depth, vec2<i32>(in.clip.xy), 0);
+    let tolerance = stored * 1e-3 + 1e-7;
+    // Not what the world shows here: a transparent texel, or behind something.
+    if in.translucent != 0u {
+        let alpha = textureSampleLevel(atlas, atlas_sampler, in.uv, 0.0).a;
+        if alpha < 0.1 || in.clip.z < stored - tolerance {
+            discard;
+        }
+    } else if abs(in.clip.z - stored) > tolerance {
+        discard;
+    }
+    if in.previous.w <= 0.0 {
+        discard;
+    }
+    let now = in.current.xy / in.current.w;
+    let then = in.previous.xy / in.previous.w;
+    return vec4((then - now) * vec2(0.5, -0.5), 1.0, 0.0);
+}

crates/horizon-client-render/src/gfx/hdr.rs

@@ -366,7 +366,11 @@ impl Hdr {
     /// Keeps the world as drawn so far, before the hand and HUD cover it, then zeroes the
     /// frame's alpha: the world's marks live on in the copy, and whatever draws from here
     /// on raises the alpha where it covers the world.
-    pub fn keep_world(&self, encoder: &mut wgpu::CommandEncoder) {
+    pub fn keep_world(
+        &self,
+        encoder: &mut wgpu::CommandEncoder,
+        timing: Option<&mut super::pack_timing::PassTiming>,
+    ) {
         let Some(t) = &self.targets else {
             return;
         };
@@ -387,6 +391,7 @@ impl Hdr {
         })];
         let mut pass = encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
             label: Some("Horizon HDR UI mask"),
+            timestamp_writes: timing.and_then(|t| t.writes("HDR UI mask")),
             color_attachments: &attachments,
             ..Default::default()
         });
@@ -397,7 +402,11 @@ impl Hdr {
     /// After the hand: its pixels' alpha goes down to 1/255, below anything the HUD and
     /// menus leave, so HDR output tells the hand (the world's brightness, never lifted)
     /// from the UI (UI Brightness).
-    pub fn mark_hand(&self, encoder: &mut wgpu::CommandEncoder) {
+    pub fn mark_hand(
+        &self,
+        encoder: &mut wgpu::CommandEncoder,
+        timing: Option<&mut super::pack_timing::PassTiming>,
+    ) {
         let Some(t) = &self.targets else {
             return;
         };
@@ -413,6 +422,7 @@ impl Hdr {
         })];
         let mut pass = encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
             label: Some("Horizon HDR hand mark"),
+            timestamp_writes: timing.and_then(|t| t.writes("HDR hand mark")),
             color_attachments: &attachments,
             ..Default::default()
         });
@@ -434,6 +444,7 @@ impl Hdr {
         encoder: &mut wgpu::CommandEncoder,
         target: &wgpu::Texture,
         world: bool,
+        timing: Option<&mut super::pack_timing::PassTiming>,
     ) {
         let Some(t) = &self.targets else {
             return;
@@ -443,7 +454,7 @@ impl Hdr {
             0,
             bytemuck::cast_slice(&self.params(world, self.output == Output::Pq)),
         );
-        Self::draw(encoder, &self.pipeline, &t.group, target);
+        Self::draw(encoder, &self.pipeline, &t.group, target, timing);
     }
 
     /// The frame `present` writes, as HDR10 (BT.2020, PQ, 10 bits a channel) whatever
@@ -494,7 +505,7 @@ impl Hdr {
             0,
             bytemuck::cast_slice(&self.params(world, true)),
         );
-        Self::draw(encoder, &self.capture_pipeline, &group, &texture);
+        Self::draw(encoder, &self.capture_pipeline, &group, &texture, None);
         Some(texture)
     }
 
@@ -528,6 +539,7 @@ impl Hdr {
         pipeline: &wgpu::RenderPipeline,
         group: &wgpu::BindGroup,
         target: &wgpu::Texture,
+        timing: Option<&mut super::pack_timing::PassTiming>,
     ) {
         let view = target.create_view(&Default::default());
         let attachments = [Some(wgpu::RenderPassColorAttachment {
@@ -541,6 +553,7 @@ impl Hdr {
         })];
         let mut pass = encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
             label: Some("Horizon HDR"),
+            timestamp_writes: timing.and_then(|t| t.writes("HDR output")),
             color_attachments: &attachments,
             ..Default::default()
         });

crates/horizon-client-render/src/gfx/lod.rs

@@ -1,4 +1,4 @@
-//! Far meshes share the terrain arena and passes, with their actual bounds
+//! Far meshes share the terrain arenas and passes, with their actual bounds
 //! rather than the 16³ boxes used by the near-section residency walk.
 use super::{Frustum, Renderer, SectionGpu};
 use crate::{

crates/horizon-client-render/src/gfx/native_material.rs

@@ -102,32 +102,69 @@ fn horizon_block_pbr(uv: vec2<f32>, layer: u32, lod: f32, map: u32) -> vec4<f32>
         return select(vec4<f32>(0.5, 0.5, 1.0, 1.0), vec4<f32>(0.0), map == 1u);
     }
     let s = horizon_terrain_sprite_sampler;
+    // The maps may be smaller than the colour: the same footprint is fewer of their texels.
+    let scale = f32(textureDimensions(horizon_terrain_sprites).x)
+        / f32(textureDimensions(horizon_pbr_normals).x);
+    let l = max(lod - log2(scale), 0.0);
     if map == 0u {
-        return textureSampleLevel(horizon_pbr_normals, s, uv, i32(layer), lod);
+        return textureSampleLevel(horizon_pbr_normals, s, uv, i32(layer), l);
+    }
+    return textureSampleLevel(horizon_pbr_specular, s, uv, i32(layer), l);
+}
+// The prelude's `block_texture`: a sprite of the terrain's arrays at a mip level.
+fn horizon_block_size() -> vec2<f32> {
+    return vec2<f32>(textureDimensions(horizon_terrain_sprites).xy);
+}
+fn horizon_block_sample(uv: vec2<f32>, layer: u32, lod: f32) -> vec4<f32> {
+    let s = horizon_terrain_sprite_sampler;
+    let l = i32(layer % horizon_terrain_SPRITE_SPLIT);
+    switch layer / horizon_terrain_SPRITE_SPLIT {
+        case 0u: { return textureSampleLevel(horizon_terrain_sprites, s, uv, l, lod); }
+        case 1u: { return textureSampleLevel(horizon_terrain_sprites_1, s, uv, l, lod); }
+        case 2u: { return textureSampleLevel(horizon_terrain_sprites_2, s, uv, l, lod); }
+        case 3u: { return textureSampleLevel(horizon_terrain_sprites_3, s, uv, l, lod); }
+        case 4u: { return textureSampleLevel(horizon_terrain_sprites_4, s, uv, l, lod); }
+        case 5u: { return textureSampleLevel(horizon_terrain_sprites_5, s, uv, l, lod); }
+        case 6u: { return textureSampleLevel(horizon_terrain_sprites_6, s, uv, l, lod); }
+        default: { return textureSampleLevel(horizon_terrain_sprites_7, s, uv, l, lod); }
     }
-    return textureSampleLevel(horizon_pbr_specular, s, uv, i32(layer), lod);
 }
 fn horizon_material_color(in: HorizonMaterialOut, translucent: bool) -> vec4<f32> {
     let albedo = horizon_terrain_sprite(in.uv, in.layer & 0x7fffu);
     horizon_block_layer = in.layer & 0x7fffu;
-    // The mip level of this point in the maps: their own texels, as the sampler would pick.
-    let texels = in.uv * horizon_block_pbr_size();
+    // The mip level of this point in the texture: its texels, as the sampler would pick.
+    let texels = in.uv * horizon_block_size();
     let footprint = max(dot(dpdx(texels), dpdx(texels)), dot(dpdy(texels), dpdy(texels)));
     horizon_block_lod = max(0.5 * log2(max(footprint, 1e-8)), 0.0);
     // Water draws translucent and lava solid, so the pass resolves the fluid kind.
     let fluid = select(0u, select(2u, 1u, translucent), in.fluid_quad != 0u);
     let normal = horizon_material_normal(in.position);
+    horizon_material_face_normal = normal;
+    horizon_surface = vec4<f32>(0.0);
     let tangent = horizon_material_tangent(in.position, in.uv, normal);
     return material(MaterialInput(albedo, in.tint, in.light, in.lightmap, in.position, in.uv,
         translucent, horizon_sprite_tags(in.layer & 0x7fffu),
         horizon_sprite_material(in.layer & 0x7fffu), in.clip.xy / frame.resolution,
         in.face, fluid, in.emission, normal, tangent)).color;
 }
-@fragment fn horizon_material_fs_solid(in: HorizonMaterialOut) -> @location(0) vec4<f32> {
+var<private> horizon_material_face_normal: vec3<f32>;
+struct HorizonMaterialSolid {
+    @location(0) color: vec4<f32>,
+    // The surface target's data: `set_surface`'s, then the fragment's depth, which the post
+    // stage's `surface_at` compares with the final depth.
+    @location(1) surface: vec4<f32>,
+}
+@fragment fn horizon_material_fs_solid(in: HorizonMaterialOut) -> HorizonMaterialSolid {
     let color = horizon_material_color(in, false);
     // Bit 15 of the layer marks opaque leaves (forceOpaque): no alpha cutout.
     if color.a < 0.5 && (in.layer & 0x8000u) == 0u { discard; }
-    return horizon_material_fogged(vec4(color.rgb, 1.0), in.spherical, in.cylindrical);
+    if horizon_surface.w == 0.0 {
+        set_surface(horizon_material_face_normal, 0.0, 0.0);
+    }
+    var out: HorizonMaterialSolid;
+    out.color = horizon_material_fogged(vec4(color.rgb, 1.0), in.spherical, in.cylindrical);
+    out.surface = vec4(horizon_surface.xyz, in.clip.z);
+    return out;
 }
 @fragment fn horizon_material_fs_translucent(in: HorizonMaterialOut) -> @location(0) vec4<f32> {
     let color = horizon_material_color(in, true);
@@ -167,6 +204,8 @@ pub struct NativeMaterial {
     pub solid: wgpu::RenderPipeline,
     pub translucent: wgpu::RenderPipeline,
     pub flat: Option<(wgpu::RenderPipeline, wgpu::RenderPipeline)>,
+    /// The stage calls `set_surface`: its solid pipelines also write the surface target.
+    pub writes_surface: bool,
 }
 
 /// terrain.wgsl's terrain section (its globals, bindings, sampling, lighting and fog), with
@@ -198,6 +237,10 @@ fn layer_table(name: &str, table: &[(u32, u32)]) -> String {
 
 /// The terrain shader for the pack's material stage `source`, with its sprite `tags` and
 /// `materials`.
+/// The surface target (the post stage's `scene_surface`): x the normal (two snorm16 in its
+/// bits), y smoothness, z the pack's data, w the fragment's depth.
+pub const SURFACE_FORMAT: wgpu::TextureFormat = wgpu::TextureFormat::Rgba32Float;
+
 fn shader_source(source: &str, tags: &[(u32, u32)], materials: &[(u32, u32)]) -> String {
     format!(
         "{source}\n// Horizon's terrain (terrain.wgsl)\n{}{}{}{ENTRIES}",
@@ -228,6 +271,7 @@ impl NativeMaterial {
         constants: &[(String, f64)],
         fog: bool,
     ) -> Result<Self, String> {
+        let writes_surface = horizon_shader_api::stages::calls_set_surface(&stage.source);
         let module = module(stage, shape.sprite_tags, shape.sprite_materials)?;
         let mut constants = present_constants(&module, constants);
         let sprite_names = [
@@ -274,6 +318,18 @@ impl NativeMaterial {
                 constants: &constants,
                 ..Default::default()
             };
+            let solid_targets = [
+                Some(wgpu::ColorTargetState {
+                    format: shape.format,
+                    blend,
+                    write_mask: wgpu::ColorWrites::ALL,
+                }),
+                Some(wgpu::ColorTargetState {
+                    format: SURFACE_FORMAT,
+                    blend: None,
+                    write_mask: wgpu::ColorWrites::ALL,
+                }),
+            ];
             device.create_render_pipeline(&wgpu::RenderPipelineDescriptor {
                 label: Some(&stage.label),
                 layout: Some(layout),
@@ -299,11 +355,11 @@ impl NativeMaterial {
                     module: &module,
                     entry_point: Some(fragment),
                     compilation_options: options,
-                    targets: &[Some(wgpu::ColorTargetState {
-                        format: shape.format,
-                        blend,
-                        write_mask: wgpu::ColorWrites::ALL,
-                    })],
+                    targets: if fragment == "horizon_material_fs_solid" && writes_surface {
+                        &solid_targets
+                    } else {
+                        &solid_targets[..1]
+                    },
                 }),
                 multiview_mask: None,
                 cache: None,
@@ -348,6 +404,7 @@ impl NativeMaterial {
             solid,
             translucent,
             flat,
+            writes_surface,
         })
     }
 }

crates/horizon-client-render/src/gfx/native_post.rs

@@ -14,7 +14,7 @@ use super::Frame;
 const INTERMEDIATE: wgpu::TextureFormat = wgpu::TextureFormat::Rgba16Float;
 
 /// The world's colour and depth views a set of bind groups was made for.
-type WorldViews = (wgpu::TextureView, wgpu::TextureView);
+type WorldViews = (wgpu::TextureView, wgpu::TextureView, wgpu::TextureView);
 
 /// Where a post pass draws.
 #[derive(Clone, Copy, PartialEq)]
@@ -103,6 +103,9 @@ pub struct NativePost {
 /// The `frame` every stage of a pack reads (group 3, binding 0), written once a frame, and
 /// what the material stage reads besides.
 pub struct NativeFrame {
+    /// The solid terrain's second target, the post stage's `scene_surface`.
+    surface: wgpu::Texture,
+    pub surface_view: wgpu::TextureView,
     pub(super) buffer: wgpu::Buffer,
     /// Group 3 of the sky and material stages.
     pub layout: wgpu::BindGroupLayout,
@@ -270,6 +273,8 @@ impl NativeFrame {
             label: Some("Native shader pack frame"),
             entries: &entries,
         });
+        let surface = surface_target(device, [1, 1]);
+        let surface_view = surface.create_view(&Default::default());
         let opaque_depth = depth_copy(device, [1, 1]);
         let opaque_color = color_copy(device, [1, 1], wgpu::TextureFormat::Rgba8Unorm);
         let blank = copy_target(
@@ -332,6 +337,8 @@ impl NativeFrame {
             buffer,
             layout,
             group,
+            surface,
+            surface_view,
             opaque_depth,
             opaque_color,
             reflection: blank.clone(),
@@ -468,6 +475,14 @@ impl NativeFrame {
         self.regroup(device);
     }
 
+    /// Sizes the surface target: the world's while a material stage writes it, else a blank.
+    pub fn fit_surface(&mut self, device: &wgpu::Device, size: [u32; 2]) {
+        if [self.surface.width(), self.surface.height()] != size {
+            self.surface = surface_target(device, size);
+            self.surface_view = self.surface.create_view(&Default::default());
+        }
+    }
+
     /// Binds `view` as this frame's `reflection` (`None`: the blank). The mirror is drawn
     /// before the stages read it.
     pub fn set_reflection(&mut self, device: &wgpu::Device, view: Option<&wgpu::TextureView>) {
@@ -573,6 +588,24 @@ pub fn present_constants<'a>(
         .collect()
 }
 
+/// The solid terrain's surface target of `size`, drawn and read.
+fn surface_target(device: &wgpu::Device, size: [u32; 2]) -> wgpu::Texture {
+    device.create_texture(&wgpu::TextureDescriptor {
+        label: Some("Native shader pack surface"),
+        size: wgpu::Extent3d {
+            width: size[0],
+            height: size[1],
+            depth_or_array_layers: 1,
+        },
+        mip_level_count: 1,
+        sample_count: 1,
+        dimension: wgpu::TextureDimension::D2,
+        format: super::native_material::SURFACE_FORMAT,
+        usage: wgpu::TextureUsages::RENDER_ATTACHMENT | wgpu::TextureUsages::TEXTURE_BINDING,
+        view_formats: &[],
+    })
+}
+
 fn texture_entry(binding: u32, sample_type: wgpu::TextureSampleType) -> wgpu::BindGroupLayoutEntry {
     wgpu::BindGroupLayoutEntry {
         binding,
@@ -652,6 +685,7 @@ impl NativePost {
             texture_entry(8, float),
             texture_entry(9, wgpu::TextureSampleType::Depth),
             texture_entry(10, float),
+            texture_entry(11, wgpu::TextureSampleType::Float { filterable: false }),
         ];
         entries.extend(pack_texture_entries(frame.textures.len()));
         entries
@@ -757,7 +791,7 @@ impl NativePost {
     fn prepare(
         &mut self,
         device: &wgpu::Device,
-        world: (&wgpu::TextureView, &wgpu::TextureView),
+        world: (&wgpu::TextureView, &wgpu::TextureView, &wgpu::TextureView),
         size: [u32; 2],
         history_reset: bool,
     ) {
@@ -830,8 +864,11 @@ impl NativePost {
         if self
             .groups
             .as_ref()
-            .is_some_and(|((color, depth), blank, _)| {
-                color == world.0 && depth == world.1 && *blank == blank_history
+            .is_some_and(|((color, depth, surface), blank, _)| {
+                color == world.0
+                    && depth == world.1
+                    && surface == world.2
+                    && *blank == blank_history
             })
         {
             return;
@@ -893,6 +930,10 @@ impl NativePost {
                         binding: 9,
                         resource: wgpu::BindingResource::TextureView(&self.shadow.2),
                     },
+                    wgpu::BindGroupEntry {
+                        binding: 11,
+                        resource: wgpu::BindingResource::TextureView(world.2),
+                    },
                     wgpu::BindGroupEntry {
                         binding: 10,
                         resource: wgpu::BindingResource::TextureView(&self.shadow.3),
@@ -920,7 +961,11 @@ impl NativePost {
                 })
             })
             .collect();
-        self.groups = Some(((world.0.clone(), world.1.clone()), blank_history, groups));
+        self.groups = Some((
+            (world.0.clone(), world.1.clone(), world.2.clone()),
+            blank_history,
+            groups,
+        ));
     }
 
     /// Runs the passes over the world target `world` (colour, depth) of `size`, the last onto
@@ -929,7 +974,7 @@ impl NativePost {
         &mut self,
         device: &wgpu::Device,
         encoder: &mut wgpu::CommandEncoder,
-        world: (&wgpu::TextureView, &wgpu::TextureView),
+        world: (&wgpu::TextureView, &wgpu::TextureView, &wgpu::TextureView),
         screen: &wgpu::TextureView,
         size: [u32; 2],
         history_reset: bool,
@@ -1349,7 +1394,7 @@ mod tests {
         post.run(
             &device,
             &mut encoder,
-            (&color, &depth),
+            (&color, &depth, &frame.surface_view),
             &view,
             [4, 4],
             true,
@@ -1456,7 +1501,7 @@ file = \"b.wgsl\"
             post.run(
                 &device,
                 &mut encoder,
-                (&color, &depth),
+                (&color, &depth, &frame.surface_view),
                 &view,
                 [4, 4],
                 history_reset,

crates/horizon-client-render/src/gfx/native_render.rs

@@ -6,6 +6,19 @@
 use super::Vertex;
 use super::pack_draw::EntitySpan;
 use glam::{DVec3, Mat4};
+use std::sync::atomic::{AtomicBool, Ordering};
+
+static MODS_BUILT_IN: AtomicBool = AtomicBool::new(false);
+
+/// The game was built with native mods (the game sets it at start): one of them may draw in
+/// [`native_world_drawn`], so the first-person hand keeps its own pass after it.
+pub fn set_mods_built_in(on: bool) {
+    MODS_BUILT_IN.store(on, Ordering::Relaxed);
+}
+/// Whether [`native_world_drawn`] may draw ([`set_mods_built_in`]).
+pub fn world_drawn_hooked() -> bool {
+    MODS_BUILT_IN.load(Ordering::Relaxed)
+}
 
 /// What a mod can draw with once the world is drawn: after the sky, terrain, entities,
 /// particles, weather and the world post pass, before the first-person hand, the HUD and the

crates/horizon-client-render/src/gfx/native_shadow.rs

@@ -225,8 +225,9 @@ impl ShadowMap {
         &self,
         encoder: &'e mut wgpu::CommandEncoder,
         label: &str,
+        timing: Option<&mut super::pack_timing::PassTiming>,
     ) -> wgpu::RenderPass<'e> {
-        self.depth_pass(encoder, label, wgpu::LoadOp::Clear(1.0))
+        self.depth_pass(encoder, label, wgpu::LoadOp::Clear(1.0), timing)
     }
 
     /// A depth pass that adds to the map. Entities draw here, after the translucent map was
@@ -236,7 +237,7 @@ impl ShadowMap {
         encoder: &'e mut wgpu::CommandEncoder,
         label: &str,
     ) -> wgpu::RenderPass<'e> {
-        self.depth_pass(encoder, label, wgpu::LoadOp::Load)
+        self.depth_pass(encoder, label, wgpu::LoadOp::Load, None)
     }
 
     fn depth_pass<'e>(
@@ -244,9 +245,11 @@ impl ShadowMap {
         encoder: &'e mut wgpu::CommandEncoder,
         label: &str,
         load: wgpu::LoadOp<f32>,
+        timing: Option<&mut super::pack_timing::PassTiming>,
     ) -> wgpu::RenderPass<'e> {
         encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
             label: Some(label),
+            timestamp_writes: timing.and_then(|t| t.writes(label)),
             color_attachments: &[],
             depth_stencil_attachment: Some(wgpu::RenderPassDepthStencilAttachment {
                 view: &self.view,
@@ -266,6 +269,7 @@ impl ShadowMap {
         &self,
         encoder: &'e mut wgpu::CommandEncoder,
         label: &str,
+        timing: Option<&mut super::pack_timing::PassTiming>,
     ) -> wgpu::RenderPass<'e> {
         encoder.copy_texture_to_texture(
             self.depth.as_image_copy(),
@@ -274,6 +278,7 @@ impl ShadowMap {
         );
         encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
             label: Some(label),
+            timestamp_writes: timing.and_then(|t| t.writes(label)),
             color_attachments: &[Some(wgpu::RenderPassColorAttachment {
                 view: &self.color_view,
                 resolve_target: None,
@@ -298,8 +303,8 @@ impl ShadowMap {
     /// Clears the 1×1 map of a pack without `[shadow]` once.
     pub fn clear_blank(&mut self, encoder: &mut wgpu::CommandEncoder) {
         if std::mem::take(&mut self.blank_uncleared) {
-            drop(self.begin(encoder, "Native shader pack shadow map clear"));
-            drop(self.begin_translucent(encoder, "Native shader pack shadow colour clear"));
+            drop(self.begin(encoder, "Native shader pack shadow map clear", None));
+            drop(self.begin_translucent(encoder, "Native shader pack shadow colour clear", None));
         }
     }
 }

crates/horizon-client-render/src/gfx/oit.rs

@@ -620,6 +620,7 @@ impl Oit {
         depth: &wgpu::TextureView,
         draw: &dyn Fn(&mut wgpu::RenderPass<'_>, Stage),
         extras: &Extras<'_>,
+        mut timing: Option<&mut super::pack_timing::PassTiming>,
     ) {
         let Some(t) = &self.targets else { return };
         let attachment = |view, load| {
@@ -645,7 +646,7 @@ impl Oit {
         let water_mask = extras.water_mask.zip(t.terrain_depth.as_ref());
         let cloud_depth = extras.clouds.zip(t.cloud_depth.as_ref());
         if let Some((mask, _)) = water_mask {
-            self.execute_water_mask(encoder, t, color, depth, mask);
+            self.execute_water_mask(encoder, t, color, depth, mask, timing.as_deref_mut());
         }
         let terrain_depth = water_mask.map_or(depth, |(_, d)| &d.view);
         let [c0, c1] = &t.views.coefficients;
@@ -680,6 +681,7 @@ impl Oit {
             {
                 let mut pass = encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
                     label: Some(label),
+                    timestamp_writes: timing.as_deref_mut().and_then(|t| t.writes(label)),
                     color_attachments: &first,
                     depth_stencil_attachment: read_only(terrain_depth),
                     ..Default::default()
@@ -692,6 +694,7 @@ impl Oit {
                 // the terrain's: the masks only hide water.
                 let mut pass = encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
                     label: Some(label),
+                    timestamp_writes: timing.as_deref_mut().and_then(|t| t.writes("OIT features")),
                     color_attachments: &[attachment(
                         match stage {
                             Stage::DepthBounds => &t.views.bounds,
@@ -710,7 +713,7 @@ impl Oit {
                 features(&mut pass, stage);
             }
             if stage == Stage::DepthBounds {
-                self.execute_depth_bounds_cull(encoder, t, depth);
+                self.execute_depth_bounds_cull(encoder, t, depth, timing.as_deref_mut());
             }
             if let Some((clouds, cloud_depth)) = cloud_depth {
                 self.render_clouds(
@@ -720,16 +723,18 @@ impl Oit {
                     depth,
                     (label, group, &then),
                     (clouds, cloud_depth),
+                    timing.as_deref_mut(),
                 );
             }
             if stage == Stage::DepthBounds
                 && let Some((mask, _)) = water_mask
             {
-                self.execute_water_mask(encoder, t, color, depth, mask);
+                self.execute_water_mask(encoder, t, color, depth, mask, timing.as_deref_mut());
             }
         }
         let mut pass = encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
             label: Some("OIT composite"),
+            timestamp_writes: timing.and_then(|t| t.writes("OIT composite")),
             color_attachments: &[attachment(color, wgpu::LoadOp::Load)],
             depth_stencil_attachment: Some(wgpu::RenderPassDepthStencilAttachment {
                 view: depth,
@@ -749,6 +754,7 @@ impl Oit {
     /// `CloudRenderer.renderOit` for one stage. The bounds stage first copies
     /// the world's depth (after the cull) and draws into it, so the later
     /// stages, which only read it, keep each pixel's nearest cloud face.
+    #[allow(clippy::too_many_arguments)]
     fn render_clouds(
         &self,
         encoder: &mut wgpu::CommandEncoder,
@@ -764,6 +770,7 @@ impl Oit {
             &dyn Fn(&mut wgpu::RenderPass<'_>, &wgpu::RenderPipeline),
             &Depth,
         ),
+        timing: Option<&mut super::pack_timing::PassTiming>,
     ) {
         if stage == Stage::DepthBounds {
             encoder.copy_texture_to_texture(
@@ -774,6 +781,7 @@ impl Oit {
         }
         let mut pass = encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
             label: Some(label),
+            timestamp_writes: timing.and_then(|t| t.writes("OIT clouds")),
             color_attachments: targets,
             depth_stencil_attachment: Some(wgpu::RenderPassDepthStencilAttachment {
                 view: &cloud_depth.view,
@@ -798,6 +806,7 @@ impl Oit {
         color: &wgpu::TextureView,
         depth: &wgpu::TextureView,
         mask: &dyn Fn(&mut wgpu::RenderPass<'_>),
+        timing: Option<&mut super::pack_timing::PassTiming>,
     ) {
         let Some(terrain) = &t.terrain_depth else {
             return;
@@ -810,6 +819,7 @@ impl Oit {
         // The mask pipeline writes depth only but has a colour target.
         let mut pass = encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
             label: Some("OIT water mask"),
+            timestamp_writes: timing.and_then(|t| t.writes("OIT water mask")),
             color_attachments: &[Some(wgpu::RenderPassColorAttachment {
                 view: color,
                 resolve_target: None,
@@ -840,6 +850,7 @@ impl Oit {
         encoder: &mut wgpu::CommandEncoder,
         t: &Targets,
         depth: &wgpu::TextureView,
+        timing: Option<&mut super::pack_timing::PassTiming>,
     ) {
         encoder.copy_texture_to_texture(
             t.bounds.as_image_copy(),
@@ -852,6 +863,7 @@ impl Oit {
         );
         let mut pass = encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
             label: Some("OIT cull depth bounds"),
+            timestamp_writes: timing.and_then(|t| t.writes("OIT cull depth bounds")),
             color_attachments: &[Some(wgpu::RenderPassColorAttachment {
                 view: &t.views.culled,
                 resolve_target: None,

crates/horizon-client-render/src/gfx/oit_features.rs

@@ -217,7 +217,12 @@ impl Features {
                 &entity_module,
                 entities,
                 &entity_buffers,
-                kind("additive entities", "lightning", None, PLAIN),
+                kind(
+                    "additive entities",
+                    "lightning",
+                    Some(wgpu::Face::Back),
+                    PLAIN,
+                ),
             ),
             weather: set(
                 &entity_module,

crates/horizon-client-render/src/gfx/pack_post.rs

@@ -3117,8 +3117,7 @@ impl PackPost {
 
     /// What the shadow camera draws of the terrain this frame, when the pack draws it.
     pub fn shadow_view(&self, frame: &super::Frame) -> Option<ShadowView> {
-        self.shadow_targets.as_ref()?;
-        if self.shadow_terrain.is_none() && self.shadow_water.is_none() {
+        if !self.has_shadow() {
             return None;
         }
         let shadow = &self.uniforms.shadow;
@@ -3139,6 +3138,12 @@ impl PackPost {
         self.terrain.is_some()
     }
 
+    /// Whether the pack's shadow pass draws terrain (`shadow_view`).
+    pub fn has_shadow(&self) -> bool {
+        self.shadow_targets.is_some()
+            && (self.shadow_terrain.is_some() || self.shadow_water.is_some())
+    }
+
     /// Whether the pack draws the sky (disc, sunset, stars, void) itself.
     /// What the world's background is when the pack draws the sky: colortex0's clear colour
     /// (`None`: the fog colour, its default).

crates/horizon-client-render/src/gfx/pack_timing.rs

@@ -1,5 +1,6 @@
-//! GPU time of each pass of a shader pack, of either kind: shown in the F3 overlay while it is
-//! open, and logged every `REPORT` timed frames with `HORIZON_SHADER_PACK_TIMING=1`. One frame
+//! GPU time of each pass of a shader pack, of either kind, and of Horizon's own passes: shown in
+//! the F3 overlay while it is open, and logged every `REPORT` timed frames with
+//! `HORIZON_SHADER_PACK_TIMING=1`. One frame
 //! at a time is timed, and the CPU never waits for it: its timestamps are resolved in a later
 //! frame, once the GPU has finished it (Metal resolves them without waiting for the passes that
 //! write them), then read back when mapped. The next frame after that is timed again.
@@ -139,6 +140,12 @@ impl PassTiming {
         Some(stamps(&self.queries, i))
     }
 
+    /// Timestamp writes for the compute pass `name`, in a timed frame.
+    pub fn compute_writes(&mut self, name: &str) -> Option<wgpu::ComputePassTimestampWrites<'_>> {
+        let i = self.push(name)?;
+        Some(compute_stamps(&self.queries, i))
+    }
+
     /// The index of the timed frame's next pass, `name`.
     fn push(&mut self, name: &str) -> Option<u32> {
         let i = self.names.len() as u32;
@@ -274,6 +281,15 @@ fn stamps(queries: &wgpu::QuerySet, i: u32) -> wgpu::RenderPassTimestampWrites<'
     }
 }
 
+/// The compute pass's twin of `stamps`.
+fn compute_stamps(queries: &wgpu::QuerySet, i: u32) -> wgpu::ComputePassTimestampWrites<'_> {
+    wgpu::ComputePassTimestampWrites {
+        query_set: queries,
+        beginning_of_pass_write_index: Some(2 * i),
+        end_of_pass_write_index: Some(2 * i + 1),
+    }
+}
+
 /// Each pass's time in milliseconds from its (beginning, end) timestamps, `None` for a pass
 /// the GPU left unstamped. Passes overlap on tiled GPUs (a pass begins before the one before it
 /// ends): a pass costs the time from the later of its beginning and the previous pass's end.

crates/horizon-client-render/src/gfx/pack_uniforms.rs

@@ -35,10 +35,35 @@ pub struct PackInputs {
     /// `heldItemId`, `heldItemId2` (item.properties, 5.3) and `heldBlockLightValue(2)`.
     pub held_items: [i32; 2],
     pub held_light: [i32; 2],
+    /// `isRightHanded` (the Main Hand option) and `is_on_ground`.
+    pub right_handed: bool,
+    pub on_ground: bool,
+    /// The dimension type's lowest block (`bedrockLevel`), build height (`heightLimit`),
+    /// logical height, sky light and ceiling.
+    pub min_y: i32,
+    pub height: i32,
+    pub logical_height: i32,
+    pub has_skylight: bool,
+    pub has_ceiling: bool,
+    /// `isElytraFlying`: the player is fall flying.
+    pub elytra_flying: bool,
+    /// `cloudHeight`, see [`cloud_height`].
+    pub cloud_height: f32,
     /// The values native mods hand their packs (`frame.mods`, `native_shader_params`).
     pub mod_params: [[f32; 4]; 8],
 }
 
+/// The `cloudHeight` uniform. Vanilla reads `visual/cloud_height` only while the cloud color
+/// has alpha (`LevelExtractor`); a dimension without clouds has no height, which the uniform
+/// reports as NaN. NaN is not vanilla's own value: packs map it to "no clouds".
+pub fn cloud_height(cloud_color_alpha: f32, height: f32) -> f32 {
+    if crate::clouds::has_color(cloud_color_alpha) {
+        height
+    } else {
+        f32::NAN
+    }
+}
+
 /// One uniform's value: up to 16 floats or 3 integers.
 #[derive(Clone, Copy, Debug)]
 pub enum Value {
@@ -173,6 +198,15 @@ pub const NAMES: &[&str] = &[
     "playerLookVector",
     "playerBodyVector",
     "firstPersonCamera",
+    "isRightHanded",
+    "is_on_ground",
+    "bedrockLevel",
+    "heightLimit",
+    "logicalHeightLimit",
+    "hasSkylight",
+    "hasCeiling",
+    "isElytraFlying",
+    "cloudHeight",
 ];
 
 /// Values carried from frame to frame.
@@ -380,6 +414,13 @@ impl FrameUniforms {
                 "relativeEyePosition" => v3((frame.camera - frame.eye).as_vec3()),
                 "playerLookVector" | "playerBodyVector" => v3(look),
                 "firstPersonCamera" => Value::i(&[i32::from(frame.first_person)]),
+                "isRightHanded" => Value::i(&[i32::from(inputs.right_handed)]),
+                "is_on_ground" => Value::i(&[i32::from(inputs.on_ground)]),
+                "bedrockLevel" => Value::i(&[inputs.min_y]),
+                "heightLimit" => Value::i(&[inputs.height]),
+                "logicalHeightLimit" => Value::i(&[inputs.logical_height]),
+                "hasSkylight" => Value::i(&[i32::from(inputs.has_skylight)]),
+                "hasCeiling" => Value::i(&[i32::from(inputs.has_ceiling)]),
                 "eyeAltitude" => Value::f(&[frame.camera.y as f32]),
                 "upPosition" => v3(to_view(Vec3::new(0.0, 100.0, 0.0))),
                 "sunPosition" => v3(sun),
@@ -439,6 +480,8 @@ impl FrameUniforms {
                 "heldItemId2" => Value::i(&[inputs.held_items[1]]),
                 "heldBlockLightValue" => Value::i(&[inputs.held_light[0]]),
                 "heldBlockLightValue2" => Value::i(&[inputs.held_light[1]]),
+                "isElytraFlying" => Value::i(&[inputs.elytra_flying as i32]),
+                "cloudHeight" => Value::f(&[inputs.cloud_height]),
                 // renderStage is NONE outside gbuffers draws.
                 _ => Value::i(&[0]),
             }
@@ -533,6 +576,25 @@ mod tests {
         assert_eq!(out[60..64], [0; 4], "a value past the block is dropped");
     }
 
+    #[test]
+    fn cloud_height_needs_a_cloud_color() {
+        assert_eq!(cloud_height(0.8, 192.33), 192.33);
+        assert_eq!(cloud_height(0.8, 120.0), 120.0);
+        assert!(cloud_height(0.0, 192.33).is_nan());
+    }
+
+    #[test]
+    fn elytra_and_cloud_height_uniforms_are_written() {
+        assert!(NAMES.ends_with(&["isElytraFlying", "cloudHeight"]));
+        let mut out = vec![0u8; 16];
+        Value::i(&[1]).write("bool", &mut out, 0);
+        assert_eq!(i32::from_ne_bytes(out[0..4].try_into().unwrap()), 1);
+        Value::f(&[192.33]).write("float", &mut out, 4);
+        assert_eq!(f32::from_ne_bytes(out[4..8].try_into().unwrap()), 192.33);
+        Value::f(&[f32::NAN]).write("float", &mut out, 8);
+        assert!(f32::from_ne_bytes(out[8..12].try_into().unwrap()).is_nan());
+    }
+
     #[test]
     fn noon_is_straight_up_and_the_sun_sets_in_the_west() {
         assert!(body(0.0, 0.0).abs_diff_eq(Vec3::new(0.0, 100.0, 0.0), 1e-3));

crates/horizon-client-render/src/gfx/submit.rs

@@ -0,0 +1,228 @@
+//! The frame's commands finished, submitted and presented on a thread of their own.
+//!
+//! wgpu records a pass's commands lazily: `CommandEncoder::finish` validates and
+//! encodes the whole frame (about 0.1 ms with the submit), work the window's thread
+//! would otherwise wait for before building the next frame. The renderer hands the
+//! frame's encoder to [`Queue::submit_later`] and goes on; every use of the queue
+//! ([`Deref`]) first waits for that frame to be submitted, so writes, copies and
+//! submissions keep the order they had on one thread.
+use std::ops::Deref;
+use std::sync::atomic::{AtomicBool, Ordering};
+use std::sync::{Mutex, mpsc};
+
+/// Whether frames go to the submit thread, unless `HORIZON_SUBMIT_THREAD` says (`0` off, `1` on):
+/// on Linux, where it was measured faster (+32% FPS in a CPU-bound view on Vulkan, #5779). On
+/// macOS's Metal it stalled: offscreen at render distance 12, a tenth to a half of the frame rate
+/// with 20-180 ms p99 frames, against the same binary without it. Windows is not measured yet.
+pub fn wanted() -> bool {
+    match std::env::var("HORIZON_SUBMIT_THREAD").as_deref() {
+        Ok("0") => false,
+        Ok("1") => true,
+        _ => cfg!(target_os = "linux"),
+    }
+}
+
+/// Work to start right after a frame's submission (a readback's `map_async`).
+pub type AfterSubmit = Box<dyn FnOnce() + Send>;
+
+/// A frame for the submit thread: its commands and, in a window, the surface to present.
+pub struct Job {
+    pub encoder: wgpu::CommandEncoder,
+    pub surface: Option<wgpu::SurfaceTexture>,
+    pub after: Option<AfterSubmit>,
+}
+
+struct Thread {
+    jobs: Option<mpsc::Sender<Job>>,
+    handle: Option<std::thread::JoinHandle<()>>,
+}
+
+/// What the submit thread sent back, once it is taken in by [`Queue::wait`].
+struct Landing {
+    done: mpsc::Receiver<wgpu::SubmissionIndex>,
+    landed: Option<wgpu::SubmissionIndex>,
+}
+
+/// The device's queue, with frames submitted on the submit thread when it runs.
+pub struct Queue {
+    queue: wgpu::Queue,
+    thread: Option<Thread>,
+    /// A frame went to the submit thread and has not been waited for.
+    pending: AtomicBool,
+    landing: Mutex<Option<Landing>>,
+}
+
+impl Queue {
+    /// `threaded`: frames may go to a submit thread (the renderer asks [`wanted`]).
+    pub fn new(queue: wgpu::Queue, threaded: bool) -> Self {
+        let mut this = Self {
+            queue,
+            thread: None,
+            pending: AtomicBool::new(false),
+            landing: Mutex::new(None),
+        };
+        if !threaded {
+            return this;
+        }
+        let (jobs, job_rx) = mpsc::channel::<Job>();
+        let (done_tx, done) = mpsc::channel();
+        let queue = this.queue.clone();
+        let spawned = std::thread::Builder::new()
+            .name("Render submit".into())
+            .spawn(move || {
+                for job in job_rx {
+                    let commands = job.encoder.finish();
+                    let submission = queue.submit([commands]);
+                    if let Some(after) = job.after {
+                        after();
+                    }
+                    if let Some(surface) = job.surface {
+                        queue.present(surface);
+                    }
+                    if done_tx.send(submission).is_err() {
+                        break;
+                    }
+                }
+            });
+        match spawned {
+            Ok(handle) => {
+                this.thread = Some(Thread {
+                    jobs: Some(jobs),
+                    handle: Some(handle),
+                });
+                *this.lock() = Some(Landing { done, landed: None });
+            }
+            Err(e) => log::warn!("Horizon renderer: no submit thread ({e}); submitting in place"),
+        }
+        this
+    }
+    fn lock(&self) -> std::sync::MutexGuard<'_, Option<Landing>> {
+        self.landing
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner)
+    }
+    /// Whether frames can go to the submit thread.
+    pub fn threaded(&self) -> bool {
+        self.thread.is_some()
+    }
+    /// Finish, submit and present the frame on the submit thread, then run its `after`;
+    /// given back, with nothing done, when there is none.
+    pub fn submit_later(&self, job: Job) -> Result<(), Box<Job>> {
+        let Some(jobs) = self.thread.as_ref().and_then(|t| t.jobs.as_ref()) else {
+            return Err(Box::new(job));
+        };
+        self.wait();
+        match jobs.send(job) {
+            Ok(()) => {
+                self.pending.store(true, Ordering::Release);
+                Ok(())
+            }
+            Err(mpsc::SendError(job)) => Err(Box::new(job)),
+        }
+    }
+    /// Wait until the frame on the submit thread is submitted and presented.
+    pub fn wait(&self) {
+        if !self.pending.load(Ordering::Acquire) {
+            return;
+        }
+        let mut landing = self.lock();
+        if !self.pending.load(Ordering::Acquire) {
+            return;
+        }
+        if let Some(l) = landing.as_mut() {
+            // A thread that died (a wgpu panic on it) panics here, as it would have in place.
+            let submission = l
+                .done
+                .recv()
+                .expect("Horizon renderer: the submit thread stopped");
+            l.landed = Some(submission);
+        }
+        self.pending.store(false, Ordering::Release);
+    }
+    /// The submission of the frame [`submit_later`](Self::submit_later) took, once it is
+    /// made; `None` if it was taken already.
+    pub fn landed(&self) -> Option<wgpu::SubmissionIndex> {
+        self.wait();
+        self.lock().as_mut().and_then(|l| l.landed.take())
+    }
+}
+
+impl Deref for Queue {
+    type Target = wgpu::Queue;
+    fn deref(&self) -> &wgpu::Queue {
+        self.wait();
+        &self.queue
+    }
+}
+
+impl Drop for Queue {
+    fn drop(&mut self) {
+        self.wait();
+        if let Some(thread) = &mut self.thread {
+            thread.jobs.take();
+            if let Some(handle) = thread.handle.take() {
+                let _ = handle.join();
+            }
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn device() -> Option<(wgpu::Device, wgpu::Queue)> {
+        let instance = wgpu::Instance::new(wgpu::InstanceDescriptor::new_without_display_handle());
+        let adapter = pollster::block_on(instance.request_adapter(&Default::default())).ok()?;
+        pollster::block_on(adapter.request_device(&Default::default())).ok()
+    }
+
+    fn buffer(device: &wgpu::Device, usage: wgpu::BufferUsages) -> wgpu::Buffer {
+        device.create_buffer(&wgpu::BufferDescriptor {
+            label: None,
+            size: 4,
+            usage,
+            mapped_at_creation: false,
+        })
+    }
+
+    #[test]
+    fn writes_after_a_frame_on_the_thread_land_after_it() {
+        let Some((device, queue)) = device() else {
+            return;
+        };
+        let queue = Queue::new(queue, true);
+        assert!(queue.threaded());
+        use wgpu::BufferUsages as U;
+        let source = buffer(&device, U::COPY_SRC | U::COPY_DST);
+        let copy = buffer(&device, U::COPY_SRC | U::COPY_DST);
+        let read = buffer(&device, U::MAP_READ | U::COPY_DST);
+        queue.write_buffer(&source, 0, &[1, 2, 3, 4]);
+        for frame in 0..3u8 {
+            // The frame copies `source`; the next frame's write must not reach that copy.
+            let mut encoder = device.create_command_encoder(&Default::default());
+            encoder.copy_buffer_to_buffer(&source, 0, &copy, 0, 4);
+            let job = Job {
+                encoder,
+                surface: None,
+                after: None,
+            };
+            assert!(queue.submit_later(job).is_ok());
+            queue.write_buffer(&source, 0, &[frame + 10; 4]);
+            assert!(queue.landed().is_some(), "frame {frame} submitted");
+            let mut encoder = device.create_command_encoder(&Default::default());
+            encoder.copy_buffer_to_buffer(&copy, 0, &read, 0, 4);
+            queue.submit([encoder.finish()]);
+            read.slice(..)
+                .map_async(wgpu::MapMode::Read, |r| r.unwrap());
+            device.poll(wgpu::PollType::wait_indefinitely()).unwrap();
+            let expected = if frame == 0 {
+                [1, 2, 3, 4]
+            } else {
+                [frame + 9; 4]
+            };
+            assert_eq!(*read.slice(..).get_mapped_range().unwrap(), expected);
+            read.unmap();
+        }
+    }
+}

crates/horizon-client-render/src/gfx/world_post.rs

@@ -437,14 +437,15 @@ impl Post {
         queue: &wgpu::Queue,
         encoder: &mut wgpu::CommandEncoder,
         screen: &wgpu::TextureView,
+        mut timing: Option<&mut super::pack_timing::PassTiming>,
     ) {
         let Some(target) = &self.target else { return };
         let Some(taa) = target.taa.as_ref().filter(|_| self.taa_previous.is_some()) else {
-            self.finish_with(encoder, screen, &target.group);
+            self.finish_with(encoder, screen, &target.group, timing.as_deref_mut());
             return;
         };
         let Some(res) = &self.taa_resources else {
-            self.finish_with(encoder, screen, &target.group);
+            self.finish_with(encoder, screen, &target.group, timing.as_deref_mut());
             return;
         };
         let i = (self.taa_frame % 2) as usize;
@@ -460,6 +461,7 @@ impl Post {
         })];
         let mut pass = encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
             label: Some("Horizon TAA"),
+            timestamp_writes: timing.as_deref_mut().and_then(|t| t.writes("TAA")),
             color_attachments: &attachments,
             ..Default::default()
         });
@@ -467,7 +469,7 @@ impl Post {
         pass.set_bind_group(0, &taa.resolve[i], &[]);
         pass.draw(0..3, 0..1);
         drop(pass);
-        self.finish_with(encoder, screen, &taa.show[i]);
+        self.finish_with(encoder, screen, &taa.show[i], timing);
     }
 
     /// Draw what `group` binds (`bind`) onto `screen`.
@@ -476,6 +478,7 @@ impl Post {
         encoder: &mut wgpu::CommandEncoder,
         screen: &wgpu::TextureView,
         group: &wgpu::BindGroup,
+        timing: Option<&mut super::pack_timing::PassTiming>,
     ) {
         let attachments = [Some(wgpu::RenderPassColorAttachment {
             view: screen,
@@ -488,6 +491,7 @@ impl Post {
         })];
         let mut pass = encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
             label: Some("Horizon post"),
+            timestamp_writes: timing.and_then(|t| t.writes("Post")),
             color_attachments: &attachments,
             ..Default::default()
         });

crates/horizon-client-render/src/graphics.rs

@@ -79,6 +79,47 @@ impl Preset {
     }
 }
 
+/// Entity occlusion strategy. The synchronous mode preserves the original
+/// same-frame CPU test; asynchronous results only hide a mesh when their
+/// camera, bounds and occluder evidence still match.
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Default)]
+pub enum EntityCullingMode {
+    #[default]
+    Off,
+    Synchronous,
+    Asynchronous,
+}
+impl EntityCullingMode {
+    pub const ALL: [EntityCullingMode; 3] = [
+        EntityCullingMode::Off,
+        EntityCullingMode::Synchronous,
+        EntityCullingMode::Asynchronous,
+    ];
+    pub fn name(self) -> &'static str {
+        match self {
+            Self::Off => "off",
+            Self::Synchronous => "sync",
+            Self::Asynchronous => "async",
+        }
+    }
+    pub fn label(self) -> &'static str {
+        match self {
+            Self::Off => "Off",
+            Self::Synchronous => "Synchronous",
+            Self::Asynchronous => "Asynchronous",
+        }
+    }
+    fn parse(s: &str) -> Self {
+        match s {
+            // Keep graphics files written before the mode selector readable.
+            "true" | "synchronous" | "sync" => Self::Synchronous,
+            "false" | "off" => Self::Off,
+            "asynchronous" | "async" => Self::Asynchronous,
+            _ => Self::default(),
+        }
+    }
+}
+
 /// How the swapchain presents frames.
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Default)]
 pub enum PresentMode {
@@ -246,6 +287,61 @@ impl FarDetail {
     }
 }
 
+/// What the section mesher does with leaf faces inside a canopy. Terrain
+/// geometry only: entities, particles and block entities are untouched.
+#[derive(Clone, Copy, Debug, Default, PartialEq, Eq)]
+pub enum LeafCullingMode {
+    /// Every leaf face, as vanilla's fancy leaves draw them.
+    #[default]
+    Off,
+    /// Leaves surrounded on all six sides by leaves or full opaque cubes draw
+    /// in the opaque layer, so their cutouts no longer show the layers behind.
+    Solid,
+    /// Like `Solid`, but a leaf with one open side draws opaque too: the
+    /// exposed shell thins by a layer and the canopy looks chunkier.
+    SolidAggressive,
+    /// Drops the faces two leaves share. Faces toward air, cavities, partial
+    /// models, unknown neighbours and section boundaries stay.
+    Hollow,
+}
+impl LeafCullingMode {
+    pub const ALL: [LeafCullingMode; 4] = [
+        LeafCullingMode::Off,
+        LeafCullingMode::Solid,
+        LeafCullingMode::SolidAggressive,
+        LeafCullingMode::Hollow,
+    ];
+    pub fn name(self) -> &'static str {
+        match self {
+            LeafCullingMode::Off => "off",
+            LeafCullingMode::Solid => "solid",
+            LeafCullingMode::SolidAggressive => "solid_aggressive",
+            LeafCullingMode::Hollow => "hollow",
+        }
+    }
+    pub fn label(self) -> &'static str {
+        match self {
+            LeafCullingMode::Off => "Off",
+            LeafCullingMode::Solid => "Solid",
+            LeafCullingMode::SolidAggressive => "Solid Aggressive",
+            LeafCullingMode::Hollow => "Hollow",
+        }
+    }
+    /// Whether this mode draws interior leaf faces in the solid layer.
+    pub fn is_interior(self) -> bool {
+        matches!(
+            self,
+            LeafCullingMode::Solid | LeafCullingMode::SolidAggressive
+        )
+    }
+    fn parse(s: &str) -> Self {
+        Self::ALL
+            .into_iter()
+            .find(|mode| mode.name() == s)
+            .unwrap_or_default()
+    }
+}
+
 /// TAA upscaling: the world renders this much smaller than the resolution scale's size,
 /// and TAA builds the full-size picture from the jittered frames (FSR's and DLSS's ratios).
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Default)]
@@ -325,6 +421,19 @@ pub fn hdr_offered() -> bool {
     HDR_OFFERED.load(std::sync::atomic::Ordering::Relaxed)
 }
 
+static TRANSLUCENT_BATCHING_OFFERED: std::sync::atomic::AtomicBool =
+    std::sync::atomic::AtomicBool::new(false);
+/// Whether the device can batch translucent quads (`Graphics::translucent_batching`): set when
+/// the renderer starts; not without indirect multi-draw or on OpenGL, which loops over a
+/// multi-draw's entries on the CPU, nor where vanilla frames draw flat (they read the section
+/// arena's translucent quads).
+pub fn offer_translucent_batching(on: bool) {
+    TRANSLUCENT_BATCHING_OFFERED.store(on, std::sync::atomic::Ordering::Relaxed);
+}
+pub fn translucent_batching_offered() -> bool {
+    TRANSLUCENT_BATCHING_OFFERED.load(std::sync::atomic::Ordering::Relaxed)
+}
+
 /// The farthest LOD Distance, in chunks, on integrated GPUs other than
 /// Apple's: they share the CPU's memory bandwidth, and past it far terrain
 /// costs them more frame time than it is worth.
@@ -348,6 +457,46 @@ impl Graphics {
     pub fn lod_distance_on(&self, info: &wgpu::AdapterInfo) -> u32 {
         lod_distance_capped(self.lod_distance, info)
     }
+    /// Whether the selected packs leave vanilla's block models in place.
+    /// Horizon's occlusion assumptions (entity and leaf culling) hold only
+    /// for those: a pack can replace an opaque cube's model or a leaf's.
+    pub fn vanilla_models(&self, resource_packs: &[String]) -> bool {
+        resource_packs.iter().all(|id| id == "vanilla")
+    }
+    /// The same check including packs overlaid by the connected server.
+    /// Their ids are namespaced as `server/...`, so an active server pack
+    /// disables model-dependent occlusion assumptions.
+    pub fn vanilla_models_with_server_packs<'a>(
+        &self,
+        resource_packs: impl IntoIterator<Item = &'a str>,
+        server_packs: impl IntoIterator<Item = &'a str>,
+    ) -> bool {
+        resource_packs
+            .into_iter()
+            .chain(server_packs)
+            .all(|id| id == "vanilla")
+    }
+    /// The leaf culling the mesher may apply. A pack that can replace leaf
+    /// models falls back to `Off`, which draws exactly vanilla's leaves.
+    pub fn leaf_culling_effective(&self, resource_packs: &[String]) -> LeafCullingMode {
+        if self.vanilla_models(resource_packs) {
+            self.leaf_culling
+        } else {
+            LeafCullingMode::Off
+        }
+    }
+    /// The effective mode when local and server resource packs are active.
+    pub fn leaf_culling_effective_with_server_packs<'a>(
+        &self,
+        resource_packs: impl IntoIterator<Item = &'a str>,
+        server_packs: impl IntoIterator<Item = &'a str>,
+    ) -> LeafCullingMode {
+        if self.vanilla_models_with_server_packs(resource_packs, server_packs) {
+            self.leaf_culling
+        } else {
+            LeafCullingMode::Off
+        }
+    }
 }
 #[derive(Clone, Debug, PartialEq)]
 pub struct Graphics {
@@ -358,8 +507,12 @@ pub struct Graphics {
     pub far_detail: FarDetail,
     /// Skip sections hidden behind closed ones (vanilla's occlusion graph).
     pub cave_culling: bool,
-    /// Skip drawing entities hidden behind opaque terrain.
-    pub entity_culling: bool,
+    /// Skip drawing entities hidden behind opaque terrain, synchronously or asynchronously.
+    pub entity_culling: EntityCullingMode,
+    /// Terrain leaf faces inside a canopy (see [`LeafCullingMode`]); `Off` draws
+    /// vanilla's fancy leaves. Ignored with a resource pack that may replace
+    /// the vanilla leaf models ([`Graphics::leaf_culling_effective`]).
+    pub leaf_culling: LeafCullingMode,
     /// Meshed sections uploaded per frame; 0 uploads all that are ready.
     pub chunk_updates: u32,
     /// Section mesh bytes uploaded per frame, in KiB; 0 is unlimited.
@@ -415,6 +568,11 @@ pub struct Graphics {
     pub shadow_cache: bool,
     /// The graphics API (Windows only; see `GraphicsApi`).
     pub api: GraphicsApi,
+    /// Translucent quads in vertex buffers of their own (`gfx`'s translucent arena), so their
+    /// back-to-front draws go out in a few calls, for a little more video memory. Off by
+    /// default for now; read when a renderer is made (start, resource-pack reload), where it is
+    /// offered (`translucent_batching_offered`).
+    pub translucent_batching: bool,
     /// The shader pack picked in `shaderpacks/` (`shader_pack_list`); empty: none. Its key is
     /// not `shaderPack`, which versions before the clean-room rewrite saved and which stays
     /// ignored.
@@ -427,7 +585,8 @@ impl Default for Graphics {
             lod_distance: 0,
             far_detail: FarDetail::Full,
             cave_culling: true,
-            entity_culling: false,
+            entity_culling: EntityCullingMode::Off,
+            leaf_culling: LeafCullingMode::Off,
             chunk_updates: 0,
             upload_budget_kib: 0,
             texture_budget_mib: 0,
@@ -454,6 +613,7 @@ impl Default for Graphics {
             battery: false,
             shadow_cache: false,
             api: GraphicsApi::Auto,
+            translucent_batching: false,
             shader_pack: String::new(),
         }
     }
@@ -495,7 +655,8 @@ impl Graphics {
                 }
                 "farDetail" => g.far_detail = FarDetail::parse(value),
                 "caveCulling" => g.cave_culling = flag(g.cave_culling),
-                "entityCulling" => g.entity_culling = flag(g.entity_culling),
+                "entityCulling" => g.entity_culling = EntityCullingMode::parse(value),
+                "leafCulling" => g.leaf_culling = LeafCullingMode::parse(value),
                 "chunkUpdates" => g.chunk_updates = number(g.chunk_updates).min(512),
                 "uploadBudgetKiB" => g.upload_budget_kib = number(g.upload_budget_kib).min(65536),
                 "textureBudgetMiB" => {
@@ -544,6 +705,7 @@ impl Graphics {
                 "hdrKey" if value.starts_with("key.") => g.hdr_key = value.to_owned(),
                 "batteryMode" => g.battery = flag(g.battery),
                 "shadowCache" => g.shadow_cache = flag(g.shadow_cache),
+                "translucentBatching" => g.translucent_batching = flag(g.translucent_batching),
                 "graphicsApi" => g.api = GraphicsApi::from_name(value).unwrap_or_default(),
                 "pickedShaderPack" => g.shader_pack = value.to_owned(),
                 "overlay" => {
@@ -560,12 +722,13 @@ impl Graphics {
     }
     pub fn serialize(&self) -> String {
         format!(
-            "preset:{}\nlodDistance:{}\nfarDetail:{}\ncaveCulling:{}\nentityCulling:{}\nchunkUpdates:{}\nuploadBudgetKiB:{}\ntextureBudgetMiB:{}\nsky:{}\nfog:{}\nweather:{}\nanimatedTextures:{}\nditherCutoutMips:{}\npresentMode:{}\nframePacing:{}\nworkers:{}\noverlay:{}\nresolutionScale:{}\nfxaa:{}\ntaa:{}\nupscaling:{}\nscreenshotQuality:{}\nhdr:{}\nhdrPaperWhite:{}\nhdrPeak:{}\nhdrBlackLevel:{}\nhdrUiBrightness:{}\nhdrKey:{}\nbatteryMode:{}\nshadowCache:{}\ngraphicsApi:{}\npickedShaderPack:{}\n",
+            "preset:{}\nlodDistance:{}\nfarDetail:{}\ncaveCulling:{}\nentityCulling:{}\nleafCulling:{}\nchunkUpdates:{}\nuploadBudgetKiB:{}\ntextureBudgetMiB:{}\nsky:{}\nfog:{}\nweather:{}\nanimatedTextures:{}\nditherCutoutMips:{}\npresentMode:{}\nframePacing:{}\nworkers:{}\noverlay:{}\nresolutionScale:{}\nfxaa:{}\ntaa:{}\nupscaling:{}\nscreenshotQuality:{}\nhdr:{}\nhdrPaperWhite:{}\nhdrPeak:{}\nhdrBlackLevel:{}\nhdrUiBrightness:{}\nhdrKey:{}\nbatteryMode:{}\nshadowCache:{}\ngraphicsApi:{}\npickedShaderPack:{}\ntranslucentBatching:{}\n",
             self.preset.name(),
             self.lod_distance,
             self.far_detail.name(),
             bool_text(self.cave_culling),
-            bool_text(self.entity_culling),
+            self.entity_culling.name(),
+            self.leaf_culling.name(),
             self.chunk_updates,
             self.upload_budget_kib,
             self.texture_budget_mib,
@@ -600,6 +763,7 @@ impl Graphics {
             bool_text(self.shadow_cache),
             self.api.name(),
             self.shader_pack,
+            bool_text(self.translucent_batching),
         )
     }
     /// Binds Horizon's graphics key `name` (`HDR_KEY`); false for another name.
@@ -720,7 +884,8 @@ mod tests {
             lod_distance: 256,
             far_detail: FarDetail::Reduced,
             cave_culling: false,
-            entity_culling: true,
+            entity_culling: EntityCullingMode::Synchronous,
+            leaf_culling: LeafCullingMode::SolidAggressive,
             chunk_updates: 12,
             upload_budget_kib: 4096,
             texture_budget_mib: 1536,
@@ -747,10 +912,28 @@ mod tests {
             battery: true,
             shadow_cache: true,
             api: GraphicsApi::Dx12,
+            translucent_batching: true,
             shader_pack: "Golden Hour".into(),
         };
         assert_eq!(Graphics::parse(&g.serialize()), g);
+        for mode in EntityCullingMode::ALL {
+            let graphics = Graphics {
+                entity_culling: mode,
+                ..Graphics::default()
+            };
+            assert_eq!(Graphics::parse(&graphics.serialize()), graphics);
+        }
+        assert_eq!(
+            Graphics::parse("entityCulling:true\n").entity_culling,
+            EntityCullingMode::Synchronous
+        );
+        assert_eq!(
+            Graphics::parse("entityCulling:false\n").entity_culling,
+            EntityCullingMode::Off
+        );
         assert_eq!(Graphics::parse(""), Graphics::default());
+        // Translucent Batching is opt-in for now: only the file turns it on.
+        assert!(!Graphics::default().translucent_batching);
         // 0 is Auto; anything else is a peak the slider reaches.
         assert_eq!(Graphics::parse("hdrPeak:0\n").hdr_peak, 0);
         assert_eq!(Graphics::parse("hdrPeak:50\n").hdr_peak, 200);
@@ -777,11 +960,96 @@ mod tests {
             Graphics::default()
         );
         assert_eq!(
-            Graphics::parse("workers:abc\nsky:maybe\ncullLeaves:true\nentityCulling:maybe\n"),
+            Graphics::parse(
+                "workers:abc\nsky:maybe\ncullLeaves:true\nentityCulling:maybe\nleafCulling:maybe\n"
+            ),
             Graphics::default()
         );
     }
 
+    #[test]
+    fn leaf_culling_round_trips_its_stable_names() {
+        assert_eq!(Graphics::default().leaf_culling, LeafCullingMode::Off);
+        for mode in LeafCullingMode::ALL {
+            let g = Graphics {
+                leaf_culling: mode,
+                ..Graphics::default()
+            };
+            assert_eq!(Graphics::parse(&g.serialize()), g, "{mode:?}");
+            assert_eq!(
+                Graphics::parse(&format!("leafCulling:{}\n", mode.name())).leaf_culling,
+                mode
+            );
+        }
+        for text in [
+            "leafCulling:other\n",
+            "leafCulling:\n",
+            "leafCulling:SOLID\n",
+        ] {
+            assert_eq!(
+                Graphics::parse(text).leaf_culling,
+                LeafCullingMode::Off,
+                "{text:?}"
+            );
+        }
+    }
+
+    #[test]
+    fn presets_keep_the_leaf_culling_choice() {
+        for mode in LeafCullingMode::ALL {
+            for preset in Preset::ALL {
+                let mut s = crate::settings::Settings::default();
+                s.horizon.leaf_culling = mode;
+                apply_preset(preset, &mut s);
+                assert_eq!(s.horizon.leaf_culling, mode, "{preset:?}");
+                assert_eq!(Graphics::parse(&s.horizon.serialize()), s.horizon);
+            }
+        }
+    }
+
+    #[test]
+    fn custom_packs_turn_leaf_culling_off() {
+        let g = Graphics {
+            leaf_culling: LeafCullingMode::Hollow,
+            ..Graphics::default()
+        };
+        assert!(g.vanilla_models(&["vanilla".into()]));
+        assert_eq!(
+            g.leaf_culling_effective(&["vanilla".into()]),
+            LeafCullingMode::Hollow
+        );
+        assert!(!g.vanilla_models(&["vanilla".into(), "My Pack".into()]));
+        assert_eq!(
+            g.leaf_culling_effective(&["vanilla".into(), "My Pack".into()]),
+            LeafCullingMode::Off
+        );
+        assert_eq!(g.leaf_culling_effective(&[]), LeafCullingMode::Hollow);
+    }
+
+    #[test]
+    fn server_pack_apply_disables_leaf_culling_and_removal_restores_it() {
+        let g = Graphics {
+            leaf_culling: LeafCullingMode::Solid,
+            ..Graphics::default()
+        };
+        let selected = ["vanilla"];
+        let applied_server_pack = ["server/0123456789abcdef/model-pack.zip"];
+
+        assert_eq!(
+            g.leaf_culling_effective_with_server_packs(selected, applied_server_pack),
+            LeafCullingMode::Off,
+            "an applied server pack can replace block models"
+        );
+        assert!(!g.vanilla_models_with_server_packs(selected, applied_server_pack));
+
+        assert_eq!(
+            g.leaf_culling_effective_with_server_packs(selected, []),
+            LeafCullingMode::Solid,
+            "removing the server pack restores the selected local mode"
+        );
+        assert!(g.vanilla_models_with_server_packs(selected, []));
+    }
+
     #[test]
     fn integrated_gpus_other_than_apple_cap_the_lod_distance() {
         let adapter = |name: &str, device_type| wgpu::AdapterInfo {

crates/horizon-client-render/src/graphics_ui.rs

@@ -2,7 +2,10 @@
 //! they show, in what groups, with what description and cost, and their
 //! input. How they look comes from `graphics_style`.
 use crate::{
-    graphics::{FarDetail, GraphicsApi, Overlay, Pacing, PresentMode, Preset, Upscaling},
+    graphics::{
+        EntityCullingMode, FarDetail, GraphicsApi, LeafCullingMode, Overlay, Pacing, PresentMode,
+        Preset, Upscaling,
+    },
     graphics_style::{Cost, STYLE},
     hud::{HudAtlas, HudBatch},
     lang,
@@ -27,6 +30,7 @@ pub enum H {
     FarDetail,
     CaveCulling,
     EntityCulling,
+    LeafCulling,
     ChunkUpdates,
     UploadBudget,
     Sky,
@@ -187,6 +191,12 @@ pub fn rows(level: Level) -> Vec<Row> {
                 Medium,
                 "How far away mobs and items are drawn, as a share of normal.",
             ),
+            h(
+                H::ChunkUpdates,
+                Low,
+                "Meshed sections uploaded per frame. Lower is smoother while loading.",
+            ),
+            Row::Header("Culling"),
             h(
                 H::CaveCulling,
                 Saves,
@@ -195,12 +205,12 @@ pub fn rows(level: Level) -> Vec<Row> {
             h(
                 H::EntityCulling,
                 None,
-                "Hides models behind opaque blocks. Entities update. Off with custom packs.",
+                "Hides models behind opaque blocks. Async checks off-thread; entities tick.",
             ),
             h(
-                H::ChunkUpdates,
-                Low,
-                "Meshed sections uploaded per frame. Lower is smoother while loading.",
+                H::LeafCulling,
+                Saves,
+                "Draws or drops leaf faces inside canopies. Off keeps vanilla's fancy leaves.",
             ),
             Row::Header("Quality"),
             v(
@@ -446,6 +456,16 @@ fn description(item: Item, s: &Settings, text: &'static str) -> &'static str {
         (Item::Horizon(H::HdrPeak | H::HdrPaperWhite), Setup::Automatic | Setup::Changed) => {
             "Set up for your display. Leave on Auto unless it looks wrong."
         }
+        (Item::Horizon(H::LeafCulling), _) => match s.horizon.leaf_culling {
+            LeafCullingMode::Off => "Every leaf face. Vanilla's fancy leaves.",
+            LeafCullingMode::Solid => {
+                "Leaves fully inside a canopy draw solid: fewer see-through layers."
+            }
+            LeafCullingMode::SolidAggressive => {
+                "Leaves with one open side draw solid too: faster, chunkier edges."
+            }
+            LeafCullingMode::Hollow => "Drops faces between leaves: faster, but gaps look through.",
+        },
         _ => text,
     }
 }
@@ -515,7 +535,8 @@ impl H {
             },
             H::FarDetail => labelled("Far Detail", g.far_detail.label()),
             H::CaveCulling => labelled("Cave Culling", on_off(g.cave_culling)),
-            H::EntityCulling => labelled("Entity Culling", on_off(g.entity_culling)),
+            H::EntityCulling => labelled("Entity Culling", g.entity_culling.label()),
+            H::LeafCulling => labelled("Leaf Culling", g.leaf_culling.label()),
             H::ChunkUpdates => match g.chunk_updates {
                 0 => labelled("Chunk Updates", "Unlimited"),
                 n => labelled("Chunk Updates", lang::tr("%s per frame", &[&n])),
@@ -648,7 +669,12 @@ impl H {
                 g.far_detail = step(&[FarDetail::Full, FarDetail::Reduced], g.far_detail, back)
             }
             H::CaveCulling => g.cave_culling = !g.cave_culling,
-            H::EntityCulling => g.entity_culling = !g.entity_culling,
+            H::EntityCulling => {
+                g.entity_culling = step(&EntityCullingMode::ALL, g.entity_culling, back)
+            }
+            H::LeafCulling => {
+                g.leaf_culling = step(&LeafCullingMode::ALL, g.leaf_culling, back);
+            }
             H::Sky => g.sky = !g.sky,
             H::Fog => g.fog = !g.fog,
             H::Weather => g.weather = !g.weather,
@@ -736,7 +762,6 @@ impl Item {
         let g = &s.horizon;
         Some(match self {
             Item::Horizon(H::CaveCulling) => g.cave_culling,
-            Item::Horizon(H::EntityCulling) => g.entity_culling,
             Item::Horizon(H::Sky) => g.sky,
             Item::Horizon(H::Fog) => g.fog,
             Item::Horizon(H::Weather) => g.weather,
@@ -1826,16 +1851,92 @@ mod tests {
     }
 
     #[test]
-    fn entity_culling_is_opt_in_and_toggles_from_advanced_graphics() {
+    fn leaf_culling_cycles_modes_in_the_advanced_culling_group() {
+        let mut s = Settings::default();
+        let item = Item::Horizon(H::LeafCulling);
+        assert_eq!(item.switch(&s), None);
+        assert_eq!(item.label(&s).plain(), "Leaf Culling: Off");
+        for label in ["Solid", "Solid Aggressive", "Hollow", "Off"] {
+            item.cycle(&mut s, false, [854, 480]);
+            assert_eq!(item.label(&s).plain(), format!("Leaf Culling: {label}"));
+            assert_eq!(
+                crate::graphics::Graphics::parse(&s.horizon.serialize()).leaf_culling,
+                s.horizon.leaf_culling
+            );
+        }
+        item.cycle(&mut s, true, [854, 480]);
+        assert_eq!(s.horizon.leaf_culling, LeafCullingMode::Hollow);
+
+        // The three culling settings share one group, below Rendering's chunk
+        // updates and above Quality.
+        let rows = rows(Level::Advanced);
+        let culling = rows
+            .iter()
+            .position(|row| matches!(row, Row::Header("Culling")))
+            .unwrap();
+        assert!(matches!(
+            rows.get(culling + 1),
+            Some(Row::Setting(setting)) if setting.item == Item::Horizon(H::CaveCulling)
+        ));
+        assert!(matches!(
+            rows.get(culling + 2),
+            Some(Row::Setting(setting)) if setting.item == Item::Horizon(H::EntityCulling)
+        ));
+        assert!(matches!(
+            rows.get(culling + 3),
+            Some(Row::Setting(setting)) if setting.item == item
+        ));
+        assert!(matches!(
+            rows.get(culling + 4),
+            Some(Row::Header("Quality"))
+        ));
+
+        // The description names what the picked mode does.
+        for mode in LeafCullingMode::ALL {
+            s.horizon.leaf_culling = mode;
+            let text = description(item, &s, "fallback");
+            assert_ne!(text, "fallback", "{mode:?}");
+            assert!(text.len() < 80, "{mode:?}: {text}");
+        }
+
+        // A click cycles it and leaves the preset, as the other quality
+        // settings do.
+        let mut ui = GraphicsUi::default();
+        let size = (480.0, 4000.0);
+        let (widgets, _, _) = ui.layout(Level::Advanced, &s, size.0, size.1);
+        let control = widgets
+            .iter()
+            .find(|w| matches!(w.target, Target::Item(i) if i == item))
+            .unwrap();
+        s.horizon.preset = Preset::Balanced;
+        s.horizon.leaf_culling = LeafCullingMode::Off;
+        assert_eq!(
+            ui.click(
+                Level::Advanced,
+                &mut s,
+                (control.x + 1.0, control.y + 1.0),
+                size,
+                [854, 480],
+                false,
+                false
+            ),
+            vec![Action::ButtonClick, Action::Changed]
+        );
+        assert_eq!(s.horizon.leaf_culling, LeafCullingMode::Solid);
+        assert_eq!(s.horizon.preset, Preset::Custom);
+    }
+
+    #[test]
+    fn entity_culling_modes_are_opt_in_and_cycle_from_advanced_graphics() {
         let mut s = Settings::default();
         let item = Item::Horizon(H::EntityCulling);
-        assert_eq!(item.switch(&s), Some(false));
+        assert_eq!(s.horizon.entity_culling, EntityCullingMode::Off);
         assert_eq!(item.label(&s).plain(), "Entity Culling: Off");
-        for enabled in [false, true] {
-            s.horizon.entity_culling = enabled;
+        for mode in EntityCullingMode::ALL {
+            s.horizon.entity_culling = mode;
             for preset in Preset::ALL {
                 crate::graphics::apply_preset(preset, &mut s);
-                assert_eq!(s.horizon.entity_culling, enabled);
+                assert_eq!(s.horizon.entity_culling, mode);
             }
         }
 
@@ -1847,7 +1948,11 @@ mod tests {
             .find(|w| matches!(w.target, Target::Item(i) if i == item))
             .unwrap();
         let point = (switch.x + 1.0, switch.y + 1.0);
-        for enabled in [false, true] {
+        for mode in [
+            EntityCullingMode::Off,
+            EntityCullingMode::Synchronous,
+            EntityCullingMode::Asynchronous,
+        ] {
             s.horizon.preset = Preset::Balanced;
             assert_eq!(
                 ui.click(
@@ -1861,10 +1966,10 @@ mod tests {
                 ),
                 vec![Action::ButtonClick, Action::Changed]
             );
-            assert_eq!(item.switch(&s), Some(enabled));
+            assert_eq!(s.horizon.entity_culling, mode);
             assert_eq!(s.horizon.preset, Preset::Custom);
         }
-        assert_eq!(item.label(&s).plain(), "Entity Culling: On");
+        assert_eq!(item.label(&s).plain(), "Entity Culling: Asynchronous");
     }
 
     #[test]

crates/horizon-client-render/src/hud.rs

@@ -83,6 +83,8 @@ pub struct HudAtlas {
     /// A resource pack's own `core/text` shader for the GUI's text, translated;
     /// none draws the text natively.
     pub text_shader: Option<std::sync::Arc<horizon_shaders::CoreProgram>>,
+    /// The packs' OptiFine random entity textures, whose variants this atlas packs.
+    pub random_textures: horizon_optifine::random_textures::RandomTextures,
     white: Rect,
 }
 /// Atlas rows reserved for glyphs rasterized at run time.
@@ -479,6 +481,7 @@ impl HudAtlas {
             glint_armor: (vec![0; 4], 1, 1),
             white,
             text_shader: None,
+            random_textures: Default::default(),
         }
     }
     /// Shelf placements of `images` (tallest first) in the narrowest atlas
@@ -567,15 +570,41 @@ impl HudAtlas {
             let s = p.to_string_lossy();
             !s.contains("title/background") && !s.contains("realms") && !s.contains("presets")
         });
+        // OptiFine random entity variants, under the names their scan gives them (those
+        // outside `textures/` are `<ns>:optifine/random/...`).
+        let random_textures = if folders.contains(&"entity") {
+            horizon_optifine::random_textures::RandomTextures::scan(root)
+        } else {
+            Default::default()
+        };
+        let mut named: HashMap<PathBuf, String> = HashMap::new();
+        for (file, name) in random_textures.files() {
+            named.insert(root.join(file), name.to_owned());
+        }
+        if !named.is_empty() {
+            // Those beside their texture are walked already.
+            let walked: HashSet<&PathBuf> = files.iter().collect();
+            let mut extra: Vec<PathBuf> = named
+                .keys()
+                .filter(|p| !walked.contains(p))
+                .cloned()
+                .collect();
+            extra.sort();
+            files.extend(extra);
+        }
         type Decoded = (PackedImage, Option<TextureFlags>, Option<(u32, u32)>, bool);
         let decode_one = |path: &PathBuf| -> Option<Decoded> {
-            let name = match path.strip_prefix(&textures) {
-                Ok(rel) => rel.with_extension("").to_string_lossy().replace('\\', "/"),
-                Err(_) => {
-                    let rel = path.strip_prefix(&assets).ok()?.with_extension("");
-                    let rel = rel.to_string_lossy().replace('\\', "/");
-                    let (namespace, rest) = rel.split_once("/textures/")?;
-                    format!("{namespace}:{rest}")
+            let name = if let Some(name) = named.get(path) {
+                name.clone()
+            } else {
+                match path.strip_prefix(&textures) {
+                    Ok(rel) => rel.with_extension("").to_string_lossy().replace('\\', "/"),
+                    Err(_) => {
+                        let rel = path.strip_prefix(&assets).ok()?.with_extension("");
+                        let rel = rel.to_string_lossy().replace('\\', "/");
+                        let (namespace, rest) = rel.split_once("/textures/")?;
+                        format!("{namespace}:{rest}")
+                    }
                 }
             };
             // LabPBR's maps beside a texture are the world's (sprites.rs), not images to draw.
@@ -777,6 +806,7 @@ impl HudAtlas {
             glint,
             glint_armor,
             text_shader: None,
+            random_textures,
             font,
             white,
         })
@@ -2017,9 +2047,11 @@ impl HudRenderer {
             batch,
             size,
             0..batch.vertices.len() as u32,
+            None,
         );
     }
     /// Draw part of the prepared batch, preserving its blend/depth runs.
+    #[allow(clippy::too_many_arguments)]
     pub fn draw_range(
         &self,
         encoder: &mut wgpu::CommandEncoder,
@@ -2028,6 +2060,7 @@ impl HudRenderer {
         batch: &HudBatch,
         size: [u32; 2],
         vertices: std::ops::Range<u32>,
+        mut timing: Option<&mut crate::gfx::pack_timing::PassTiming>,
     ) {
         if vertices.is_empty() || size.contains(&0) {
             return;
@@ -2058,6 +2091,7 @@ impl HudRenderer {
             };
             let mut pass = encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
                 label: Some("HUD"),
+                timestamp_writes: timing.as_deref_mut().and_then(|t| t.writes("HUD")),
                 color_attachments: &attachments,
                 depth_stencil_attachment: clip.map(|_| wgpu::RenderPassDepthStencilAttachment {
                     view: depth,

crates/horizon-client-render/src/lib.rs

@@ -18,9 +18,11 @@ pub mod camera;
 pub mod chat;
 pub mod chunk;
 pub mod chunk_map;
+pub mod cit;
 pub mod clouds;
 pub mod collisions;
 pub mod command_block;
+pub mod connected;
 pub mod containers;
 pub mod crash;
 pub mod datapack;

crates/horizon-client-render/src/lod.rs

@@ -47,6 +47,9 @@ fn meshing_threads(cores: usize) -> usize {
 /// terrain starts one sample job at most this often and no detail: it would
 /// otherwise take the cores the near chunks and the frame need.
 const HELD_SAMPLE_STEP: std::time::Duration = std::time::Duration::from_millis(500);
+/// How long a tile whose sampling failed (`LodSampler::grid` gave no
+/// columns: a server refused or lost it) waits before it is asked again.
+const RETRY: std::time::Duration = std::time::Duration::from_secs(2);
 /// The coarsest tile level: `Plan` roots cover at most `MAX_CHUNKS` chunks
 /// around (a level-22 tile is 67 million blocks wide: the whole world).
 pub(crate) const MAX_LEVEL: u8 = 22;
@@ -494,7 +497,20 @@ struct Plan {
     /// selection is rebuilt, without sorting the whole set.
     by_level: [Vec<TileKey>; MAX_LEVEL as usize + 1],
     elevation: i32,
+    camera: [i32; 2],
+    /// The squared distance within which no coarser tile stands in for
+    /// missing detail (`stands_in`): the seam with the near chunks waits
+    /// for its own tiles instead of showing broad boxes beside them.
+    near: i64,
+    /// The squared distance within which planned tiles load before the
+    /// coarse backdrop (`wanted_tiles`).
+    first: i64,
 }
+/// Chunks past the render distance where only planned tiles are drawn (two
+/// past the last near chunk, `streaming::in_view_distance`), and where they
+/// load first.
+const SEAM_CHUNKS: i32 = 3;
+const FIRST_CHUNKS: i32 = 4;
 impl Plan {
     #[cfg(test)]
     fn new(camera: [i32; 2], detail: i32, distance: u32) -> Self {
@@ -518,6 +534,9 @@ impl Plan {
         let size = 16 << level;
         let mut result = Self {
             elevation,
+            camera,
+            near: i64::from((detail + SEAM_CHUNKS) * 16).pow(2),
+            first: i64::from((detail + FIRST_CHUNKS) * 16).pow(2),
             ..Self::default()
         };
         for z in (camera[1] - range).div_euclid(size)..=(camera[1] + range).div_euclid(size) {
@@ -589,7 +608,7 @@ impl Plan {
             if complete {
                 return true;
             }
-            if ready.contains_key(&key) {
+            if ready.contains_key(&key) && self.stands_in(key) {
                 // Its mesh is clipped around every selected finer tile.
                 out.push(key);
                 return true;
@@ -602,6 +621,26 @@ impl Plan {
             false
         }
     }
+    /// Whether a split tile may draw for its missing children: only away
+    /// from the near chunks, where its cells are small on screen.
+    fn stands_in(&self, key: TileKey) -> bool {
+        key.reach(self.camera) >= self.near
+    }
+    /// The coarse tile sampled to cover `leaf` while it loads: two levels
+    /// up (16 times fewer tiles, each as cheap as a leaf to sample), one
+    /// where that would reach the seam, none beside it.
+    fn backdrop(&self, leaf: TileKey) -> Option<TileKey> {
+        let mut backdrop = None;
+        let mut key = leaf;
+        for _ in 0..2 {
+            key = key.parent();
+            if !self.nodes.contains(&key) || !self.stands_in(key) {
+                break;
+            }
+            backdrop = Some(key);
+        }
+        backdrop
+    }
     /// Whether chunk column (x, z) is drawn by the tile planned there (ready;
     /// at level 0, also `filled`) rather than by a coarser ancestor standing
     /// in for it, or is past the far terrain.
@@ -625,6 +664,47 @@ impl Plan {
         self.split.contains(&key) || (ready.contains_key(&key) && (key.level > 0 || filled(key)))
     }
 }
+/// The tiles to sample, `Wanted`'s order best first. First the planned
+/// tiles at the seam with the near chunks, nearest first: coarse tiles
+/// there cost a far tile's work for broad boxes that fine tiles replace
+/// moments later. Then a coarse backdrop (`Plan::backdrop`) out to the
+/// horizon, then every other planned tile nearest first, each replacing its
+/// part of the backdrop: the horizon fills in early and sharpens from the
+/// player outward, whichever way they look.
+fn wanted_tiles(
+    plan: &Plan,
+    ready: &FxHashMap<TileKey, impl Sized>,
+    camera: [i32; 2],
+) -> impl Iterator<Item = Wanted> {
+    let wanted = |class, key: TileKey| Wanted {
+        class,
+        distance: i64::from(key.distance(camera)),
+        x: key.x,
+        z: key.z,
+        level: key.level,
+    };
+    let mut backdrop = FxHashSet::default();
+    let mut tiles: Vec<_> = plan
+        .nodes
+        .iter()
+        .filter(|key| !plan.split.contains(key) && !ready.contains_key(key))
+        .map(|&key| {
+            if let Some(coarse) = plan.backdrop(key)
+                && !ready.contains_key(&coarse)
+            {
+                backdrop.insert(coarse);
+            }
+            let first = key.reach(camera) < plan.first;
+            wanted(if first { SEAM } else { REST }, key)
+        })
+        .collect();
+    tiles.extend(backdrop.into_iter().map(|key| wanted(BACKDROP, key)));
+    tiles.into_iter()
+}
+/// `Wanted::class`es, best first.
+const SEAM: u8 = 0;
+const BACKDROP: u8 = 1;
+const REST: u8 = 2;
 /// Visited chunks' summaries (`Lod::saved`) and their reductions.
 type Saved = FxHashMap<(i32, i32), Arc<[Column; 256]>>;
 type Reduced = FxHashMap<(i32, i32), Arc<ReducedColumns>>;
@@ -791,9 +871,11 @@ impl Ord for MeshQueued {
             .then(other.order.cmp(&self.order))
     }
 }
-/// A tile the sampler should produce next, nearest first.
-#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
+/// A tile the sampler should produce next: by `class`
+/// (`wanted_tiles`), then nearest first.
+#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord)]
 struct Wanted {
+    class: u8,
     distance: i64,
     x: i32,
     z: i32,
@@ -843,6 +925,8 @@ pub struct Lod {
     near_loading: bool,
     /// When `request_samples` last started a job while held.
     held_sample_at: std::time::Instant,
+    /// Tiles whose sampling failed, and when they may be asked again.
+    retry: FxHashMap<TileKey, std::time::Instant>,
     /// Each tile's samples, shared with mesh jobs in flight.
     ready: FxHashMap<TileKey, Arc<Vec<Column>>>,
     /// Fully covered subtrees, by tile.
@@ -1179,6 +1263,7 @@ impl Lod {
             sample_jobs: SAMPLE_JOBS.max(sampling_threads(cores) + 1),
             near_loading: false,
             held_sample_at: std::time::Instant::now(),
+            retry: FxHashMap::default(),
             ready: FxHashMap::default(),
             complete: FxHashMap::default(),
             active: FxHashSet::default(),
@@ -1411,14 +1496,15 @@ impl Lod {
         let present = self.ready.contains_key(&key);
         // Covered level-0 stand-ins complete their parent but are never drawn.
         let ready = present && !(key.level == 0 && self.covered.contains(&(key.x, key.z)));
-        // Mirrors `Plan::select`: a ready split tile is a complete
-        // stand-in even while its children are still incomplete, so no
-        // second fallback is drawn above it.
+        // Mirrors `Plan::select`: a ready split tile away from the seam is a
+        // complete stand-in even while its children are still incomplete,
+        // so no second fallback is drawn above it.
         let (complete, active) = if self.plan.split.contains(&key) {
             let children = key.children().into_iter().all(|child| {
                 !self.plan.nodes.contains(&child)
                     || self.complete.get(&child).copied().unwrap_or(false)
             });
+            let ready = ready && self.plan.stands_in(key);
             (children || ready, ready && !children)
         } else {
             (present, ready)
@@ -1609,7 +1695,16 @@ impl Lod {
     }
     fn finish_sample(&mut self, key: TileKey, samples: Vec<Column>) {
         self.pending.remove(&key);
-        if self.plan.nodes.contains(&key) && samples.len() == CELLS * CELLS {
+        if samples.len() != CELLS * CELLS {
+            let now = std::time::Instant::now();
+            if self.retry.len() > 4096 {
+                self.retry.retain(|_, at| *at > now);
+            }
+            self.retry.insert(key, now + RETRY);
+            return;
+        }
+        self.retry.remove(&key);
+        if self.plan.nodes.contains(&key) {
             let mut samples = samples;
             if let (Some(old), Some(mask)) = (self.ready.get(&key), self.detail_masks.get(&key)) {
                 for i in 0..256 {
@@ -2161,8 +2256,16 @@ impl Lod {
         if free == 0 {
             return;
         }
+        let now = std::time::Instant::now();
         if self.held() {
-            self.held_sample_at = std::time::Instant::now();
+            self.held_sample_at = now;
+        }
+        // A tile whose sampling failed waits out `RETRY`; once it has, the
+        // queue is rebuilt so the tile is asked again.
+        let retrying = self.retry.len();
+        self.retry.retain(|_, at| *at > now);
+        if self.retry.len() != retrying {
+            self.wanted_stale = true;
         }
         // The queue is rebuilt when the view moves a chunk, not scanned and
         // sorted on every frame.
@@ -2183,12 +2286,12 @@ impl Lod {
                 z: wanted.z,
                 level: wanted.level,
             };
-            // Final tiles only: a coarse tile under the near area is work
-            // that finer tiles replace moments later.
+            // Final tiles and the backdrop only (`wanted_tiles`).
             if self.pending.contains(&key)
                 || self.ready.contains_key(&key)
-                || self.plan.split.contains(&key)
+                || (self.plan.split.contains(&key) && wanted.class != BACKDROP)
                 || !self.plan.nodes.contains(&key)
+                || self.retry.contains_key(&key)
             {
                 continue;
             }
@@ -2203,17 +2306,19 @@ impl Lod {
     }
     fn rebuild_wanted(&mut self, camera: [i32; 2]) {
         self.wanted.clear();
-        for &key in &self.plan.nodes {
-            if self.plan.split.contains(&key) || self.ready.contains_key(&key) {
-                continue;
-            }
-            self.wanted.push(std::cmp::Reverse(Wanted {
-                distance: i64::from(key.distance(camera)),
-                x: key.x,
-                z: key.z,
-                level: key.level,
-            }));
-        }
+        // A failed tile waits out its retry delay (`retry`) before it is asked again.
+        let retry = &self.retry;
+        self.wanted.extend(
+            wanted_tiles(&self.plan, &self.ready, camera)
+                .filter(|w| {
+                    !retry.contains_key(&TileKey {
+                        x: w.x,
+                        z: w.z,
+                        level: w.level,
+                    })
+                })
+                .map(std::cmp::Reverse),
+        );
     }
 
     #[cfg(test)]
@@ -2607,14 +2712,14 @@ mod tests {
             (ox..ox + key.size()).contains(&(x * 16)) && (oz..oz + key.size()).contains(&(z * 16))
         };
         // 24 chunks out, now past the render distance: its planned tile was
-        // split before, so never sampled, and a root stands in for it.
+        // split before, so never sampled. The ready root reaches the seam, so
+        // it stands in for nothing: the column stays until its tile is in.
         let column = (24, 0);
         let mut selected = Vec::new();
         for &root in &after.roots {
             after.select(root, &ready, &mut selected);
         }
-        let drawn = selected.iter().filter(|key| contains(key, column));
-        assert_eq!(drawn.map(|key| key.level).min(), Some(6));
+        assert!(!selected.iter().any(|key| contains(key, column)));
         assert!(!after.replaces(column, &ready, |_| true));
         let planned = TileKey {
             x: 12,
@@ -3258,6 +3363,153 @@ mod tests {
         Ok(())
     }
 
+    #[test]
+    fn far_cells_past_render_distance_12_start_one_block_wide() {
+        // Leaves' cells: 1 block to 256 blocks out, 2 to 512 (Full); Reduced
+        // keeps 1 to the near terrain's edge and 2 to 256.
+        for (reduced, [one, two]) in [(false, [256, 512]), (true, [208, 256])] {
+            let plan = Plan::with_previous([8, 8], 12, 128, &Plan::default(), 0, reduced);
+            for key in plan.nodes.iter().filter(|key| !plan.split.contains(key)) {
+                let distance = key.distance([8, 8]);
+                if distance < one {
+                    assert_eq!(key.size() / 16, 1, "{key:?} reduced {reduced}");
+                } else if distance < two {
+                    assert!(key.size() / 16 <= 2, "{key:?} reduced {reduced}");
+                }
+            }
+        }
+    }
+    /// Loads a render distance 12 view one sample job at a time, in
+    /// `wanted_tiles`' order. Counts the jobs, and their density lattice
+    /// points (each job's cost), before every far column within two chunks
+    /// of the near terrain is drawn as finely as the plan wants it (one
+    /// block wide in Full): until then nothing is drawn there. And before
+    /// every far column is drawn, by its tile or a coarse stand-in: until
+    /// then the far terrain ends short of the horizon. Checks that no coarse
+    /// tile is ever drawn at the seam.
+    fn jobs_until_fine_seam(camera: [i32; 2], reduced: bool) -> ([(usize, i32); 2], usize) {
+        let (detail, distance) = (12, 128);
+        let center = (camera[0].div_euclid(16), camera[1].div_euclid(16));
+        let mut covered = FxHashSet::default();
+        for z in center.1 - detail..=center.1 + detail {
+            for x in center.0 - detail..=center.0 + detail {
+                if crate::streaming::in_view_distance(center, detail, x, z) {
+                    covered.insert((x, z));
+                }
+            }
+        }
+        let plan = Plan::with_previous(camera, detail, distance, &Plan::default(), 0, reduced);
+        let leaf = |x: i32, z: i32| {
+            (0..=MAX_LEVEL)
+                .map(|level| TileKey {
+                    x: x.div_euclid(16 << level),
+                    z: z.div_euclid(16 << level),
+                    level,
+                })
+                .find(|key| plan.nodes.contains(key) && !plan.split.contains(key))
+        };
+        let mut seam = Vec::new();
+        for z in (camera[1] - 256..camera[1] + 256).step_by(2) {
+            for x in (camera[0] - 256..camera[0] + 256).step_by(2) {
+                let chunk = (x.div_euclid(16), z.div_euclid(16));
+                let near = (-2..=2)
+                    .any(|dz| (-2..=2).any(|dx| covered.contains(&(chunk.0 + dx, chunk.1 + dz))));
+                if !covered.contains(&chunk) && near {
+                    seam.push((x, z, leaf(x, z).unwrap()));
+                }
+            }
+        }
+        let mut horizon = Vec::new();
+        for z in (camera[1] - 2048..camera[1] + 2048).step_by(64) {
+            for x in (camera[0] - 2048..camera[0] + 2048).step_by(64) {
+                if !covered.contains(&(x.div_euclid(16), z.div_euclid(16))) && leaf(x, z).is_some()
+                {
+                    horizon.push((x, z));
+                }
+            }
+        }
+        let mut ready: FxHashMap<TileKey, ()> = FxHashMap::default();
+        for key in &plan.nodes {
+            if key.level == 0 && covered.contains(&(key.x, key.z)) {
+                ready.insert(*key, ());
+            }
+        }
+        let leaves = plan
+            .nodes
+            .iter()
+            .filter(|k| !plan.split.contains(k))
+            .count();
+        let (mut cost, mut fine, mut reached) = (0, None, None);
+        for jobs in 0.. {
+            let mut selected = Vec::new();
+            for &root in &plan.roots {
+                plan.select(root, &ready, &mut selected);
+            }
+            let active: FxHashSet<_> = selected.into_iter().collect();
+            let drawn = |x: i32, z: i32, levels: u8| {
+                (0..=levels).any(|level| {
+                    active.contains(&TileKey {
+                        x: x.div_euclid(16 << level),
+                        z: z.div_euclid(16 << level),
+                        level,
+                    })
+                })
+            };
+            for &(x, z, leaf) in &seam {
+                assert!(drawn(x, z, leaf.level) || !drawn(x, z, MAX_LEVEL));
+            }
+            if fine.is_none() && seam.iter().all(|&(x, z, leaf)| drawn(x, z, leaf.level)) {
+                fine = Some((jobs, cost));
+            }
+            if reached.is_none() && horizon.iter().all(|&(x, z)| drawn(x, z, MAX_LEVEL)) {
+                reached = Some((jobs, cost));
+            }
+            if let (Some(fine), Some(reached)) = (fine, reached) {
+                return ([fine, reached], leaves);
+            }
+            let next = wanted_tiles(&plan, &ready, camera).min().unwrap();
+            let next = TileKey {
+                x: next.x,
+                z: next.z,
+                level: next.level,
+            };
+            // `lod_grid`'s density lattice: one point per max(stride, 4) blocks.
+            let stride = next.size() / 16;
+            let lattice = 16 * stride / stride.max(4) + 1;
+            cost += lattice * lattice;
+            ready.insert(next, ());
+        }
+        unreachable!()
+    }
+    #[test]
+    fn the_far_terrain_next_to_the_near_chunks_loads_first() {
+        // Measured: 270 to 301 jobs, all of them fine tiles (7500 to 8500
+        // lattice points). A coarse tile first costs up to 289 points; the
+        // order that filled a ring ahead first and refined broad tiles every
+        // other job took 54000 to 119000 for the seam in view alone.
+        for camera in [[8, 8], [40, -9], [-300, 517]] {
+            for reduced in [false, true] {
+                let ([(jobs, cost), _], _) = jobs_until_fine_seam(camera, reduced);
+                assert!(jobs < 320, "{jobs} jobs");
+                assert!(cost < 9000, "{cost} lattice points");
+            }
+        }
+    }
+    #[test]
+    fn a_coarse_backdrop_reaches_the_horizon_early() {
+        // Sampling only planned tiles, nearest first, reached the horizon
+        // with the last of ~3000 jobs in Full (500000 lattice points), ~1050
+        // in Reduced (200000): for minutes on a slow machine the far terrain
+        // ended in a hard edge. The backdrop adds ~230 coarse tiles (~80 in
+        // Reduced), about a tenth more work in all.
+        for camera in [[8, 8], [40, -9], [-300, 517]] {
+            for reduced in [false, true] {
+                let ([_, (jobs, cost)], leaves) = jobs_until_fine_seam(camera, reduced);
+                assert!(jobs < 1000 && jobs < leaves, "{jobs} jobs of {leaves}");
+                assert!(cost < 100_000, "{cost} lattice points");
+            }
+        }
+    }
     #[test]
     fn extra_sampling_threads_only_on_large_machines() {
         assert_eq!([1, 2, 4, 8, 11].map(sampling_threads), [1, 1, 1, 4, 5]);

crates/horizon-client-render/src/lod/mesh.rs

@@ -160,7 +160,14 @@ impl Mesher {
                 for slot in &mut faces {
                     let Some(face) = matching.next() else { break };
                     *slot = Some(Style {
-                        layer: face.layer as u16 | if leaves { OPAQUE_LAYER } else { 0 },
+                        // As the mesher marks them: opaque leaves and faces over opaque
+                        // texels skip the cutout and draw in the opaque pass.
+                        layer: face.layer as u16
+                            | if leaves || face.opaque {
+                                OPAQUE_LAYER
+                            } else {
+                                0
+                            },
                         tint: if face.quad.tint_index >= 0 {
                             tint
                         } else {

crates/horizon-client-render/src/logging.rs

@@ -59,6 +59,55 @@ pub fn set_game_home(home: PathBuf) {
     let _ = HOME.set(home);
 }
 
+/// `--player-dir DIR` (#4952), set once at start: one player's own files, when several games
+/// play in one game folder at the same time (the launcher's `play --account`).
+static PLAYER: std::sync::OnceLock<PathBuf> = std::sync::OnceLock::new();
+
+/// Makes [`player_dir`] return `dir` for the rest of the run (`--player-dir`), creating it.
+/// What is a player's own goes there: `options.txt` and the settings files beside it,
+/// `logs/`, `crash-reports/`, `horizon-player.txt`, `servers.dat`, `hotbar.nbt` and
+/// `screenshots/`. What the game folder's players share stays in it: saves, resource and
+/// shader packs, mods and their config, caches.
+pub fn set_player_dir(dir: PathBuf) {
+    let _ = fs::create_dir_all(&dir);
+    let _ = PLAYER.set(dir);
+}
+
+/// The folder of this player's own files: `--player-dir`, else the game folder (the working
+/// directory, where the launcher runs the game).
+pub fn player_dir() -> PathBuf {
+    PLAYER
+        .get()
+        .cloned()
+        .unwrap_or_else(|| std::env::current_dir().unwrap_or_default())
+}
+
+/// `--player-dir`, if given.
+pub fn player_dir_override() -> Option<&'static Path> {
+    PLAYER.get().map(PathBuf::as_path)
+}
+
+/// Where the files all players share live, for settings kept beside `options.txt` in
+/// `options_dir` (the enabled mods): that folder, unless `--player-dir` moved `options.txt`
+/// out of the game folder.
+pub fn shared_dir(options_dir: &Path) -> PathBuf {
+    shared_dir_of(PLAYER.get().map(PathBuf::as_path), options_dir, || {
+        std::env::current_dir().unwrap_or_default()
+    })
+}
+
+/// [`shared_dir`] for a given `--player-dir` and game folder.
+fn shared_dir_of(
+    player: Option<&Path>,
+    options_dir: &Path,
+    game_dir: impl FnOnce() -> PathBuf,
+) -> PathBuf {
+    match player {
+        Some(player) if player == options_dir => game_dir(),
+        _ => options_dir.to_path_buf(),
+    }
+}
+
 /// Where the launcher runs the game and keeps its saves: `--home`, else `HORIZON_HOME`, else
 /// `horizon` in the platform data folder (launcher/src/backend.rs `game_home`).
 pub fn game_home() -> PathBuf {
@@ -567,6 +616,20 @@ pub fn newest_crash_report(home: &Path) -> Option<PathBuf> {
 mod tests {
     use super::*;
 
+    #[test]
+    fn a_player_dir_keeps_the_shared_files_in_the_game_folder() {
+        let (game, player) = (Path::new("/games/shared"), Path::new("/games/players/alex"));
+        // options.txt moved to the player's folder: the enabled mods stay the game folder's.
+        assert_eq!(shared_dir_of(Some(player), player, || game.into()), game);
+        // No --player-dir, or a splitscreen profile's own folder: beside options.txt as before.
+        assert_eq!(shared_dir_of(None, game, || unreachable!()), game);
+        let profile = Path::new("/games/shared/splitscreen/profiles/P2");
+        assert_eq!(
+            shared_dir_of(Some(player), profile, || unreachable!()),
+            profile
+        );
+    }
+
     #[test]
     fn a_warning_repeated_every_packet_is_counted_past_a_hundred_a_minute() {
         let (mut floods, start) = (Floods::default(), Instant::now());

crates/horizon-client-render/src/menu_blur.rs

@@ -172,6 +172,7 @@ impl MenuBlur {
         target: &wgpu::TextureView,
         size: [u32; 2],
         radius: f32,
+        mut timing: Option<&mut crate::gfx::pack_timing::PassTiming>,
     ) {
         self.ensure(device, size);
         encoder.copy_texture_to_texture(
@@ -224,6 +225,7 @@ impl MenuBlur {
             })];
             let mut pass = encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
                 label: Some("Menu blur pass"),
+                timestamp_writes: timing.as_deref_mut().and_then(|t| t.writes("Menu blur")),
                 color_attachments: &attachments,
                 ..Default::default()
             });

crates/horizon-client-render/src/mesher.rs

@@ -4,6 +4,7 @@
 //! cardinal shading, tint sources, block offsets; see `lighting`). Fluids
 //! follow `FluidRenderer` (see `fluid`).
 mod fluid;
+mod leaf_culling;
 mod lighting;
 mod sides;
 use crate::{
@@ -11,6 +12,7 @@ use crate::{
     biome::Biomes,
     blocks::{BlockFacts, RenderShape},
     chunk::{Chunk, MIN_Y},
+    graphics::LeafCullingMode,
     models::catalog::BakedFace,
 };
 use horizon_core::{
@@ -282,6 +284,7 @@ impl SectionMesh {
         self.solid.clear();
         self.translucent.clear();
         self.block_entities.clear();
+        self.lights.clear();
         self.sprite_layers.clear();
         self.sides = Sides::default();
         self.visibility = ALL_VISIBLE;
@@ -292,6 +295,7 @@ impl SectionMesh {
         self.solid.capacity() * std::mem::size_of::<TerrainVertex>()
             + self.translucent.capacity() * std::mem::size_of::<TerrainVertex>()
             + self.block_entities.capacity() * std::mem::size_of::<([i32; 3], u32)>()
+            + self.lights.capacity() * std::mem::size_of::<([i32; 3], u32)>()
             + self.sprite_layers.capacity() * std::mem::size_of::<u16>()
     }
     /// Sorts the solid quads by the side they face, for the renderer to
@@ -468,6 +472,9 @@ struct Info {
     overlay: bool,
     /// `LeavesBlock`: with opaque leaves the faces between two leaf blocks are skipped.
     leaves: bool,
+    /// A full opaque cube: `RenderShape::Model`, `can_occlude`, `solid_render`
+    /// and a full collision shape. The only block leaf culling treats as solid.
+    opaque_cube: bool,
     blocks_flow: bool,
     ice: bool,
     sturdy: u8,
@@ -645,6 +652,12 @@ impl MeshTables {
                 legacy_solid: s.legacy_solid,
                 overlay: s.has_class("HalfTransparentBlock") || s.has_class("LeavesBlock"),
                 leaves: s.has_class("LeavesBlock"),
+                opaque_cube: leaf_culling::opaque_cube(
+                    s.render_shape,
+                    s.can_occlude,
+                    s.solid_render,
+                    s.full_collision,
+                ),
                 blocks_flow: assets.blocks_fluid_flow.contains(&*s.name),
                 ice: s.has_class("IceBlock"),
                 sturdy: s.sturdy_full,
@@ -684,6 +697,14 @@ impl MeshTables {
             tint_sources: i.tint_count,
         })
     }
+    /// Whether `state` is a full opaque cube: the only block leaf culling
+    /// treats as a solid neighbour. Glass, fluids, slabs, stairs and models
+    /// that only partly fill their block are not.
+    pub fn opaque_cube(&self, state: BlockStateId) -> bool {
+        self.info
+            .get(state.0 as usize)
+            .is_some_and(|i| i.opaque_cube)
+    }
     /// `BlockTintSource.color(state)`: block-model colour without a level.
     /// `grass` is `GrassColor.getDefaultColor()` from the active pack's colormap.
     /// Untinted faces, blank sources and invalid tint indices return `None`.
@@ -858,14 +879,18 @@ impl Padded {
     }
 }
 /// Per-worker temporary arrays. They never hold resource-pack references or
-/// geometry still owned by the renderer, and total about 88 KiB per worker.
+/// geometry still owned by the renderer, and total about 150 KiB per worker
+/// (the leaf mask adds 8,000 cells, depths and a queue).
 #[derive(Default)]
 pub(crate) struct MeshScratch {
     padded: Padded,
     own: Option<Box<[u32; 4096]>>,
     visibility: Vec<usize>,
+    leaf: leaf_culling::LeafMask,
 }
 #[cfg(test)]
+mod leaf_culling_tests;
+#[cfg(test)]
 mod reuse_tests;
 /// Set on a terrain vertex's sprite layer when its texture alpha must be ignored.
 pub const OPAQUE_LAYER: u16 = 1 << 15;
@@ -1077,6 +1102,8 @@ pub struct Mesher<'a> {
     pub smooth_lighting: bool,
     /// The `cutoutLeaves` option (fancy graphics); off makes leaves opaque.
     pub cutout_leaves: bool,
+    /// What the worker does with leaf faces inside a canopy.
+    pub leaf_culling: LeafCullingMode,
 }
 impl Mesher<'_> {
     /// `region[dz][dx]` are the chunks around the meshed column (centre 1,1).
@@ -1106,6 +1133,11 @@ impl Mesher<'_> {
         let pad = &scratch.padded;
         out.visibility = visibility_reusing(pad, &self.tables.info, &mut scratch.visibility);
         let base_y = center.min_y() + sy * 16;
+        if self.leaf_culling.is_interior() {
+            scratch
+                .leaf
+                .prepare(self.leaf_culling, pad, &self.tables.info, region, base_y);
+        }
         let mut tints = Tints::new(
             region,
             self.biomes,
@@ -1170,13 +1202,21 @@ impl Mesher<'_> {
                         None => [x as f32, y as f32, z as f32],
                     };
                     let mut visible = [false; 6];
+                    let interior_leaf = state.leaves
+                        && self.leaf_culling.is_interior()
+                        && scratch.leaf.interior(self.leaf_culling, x, y, z);
                     for d in Direction::ALL {
                         let [dx, dy, dz] = d.normal();
                         let neighbor = pad.blocks[pi(x + dx, y + dy, z + dz)];
                         let other = &info[neighbor as usize];
                         // LeavesBlock.skipRendering with opaque leaves.
                         let opaque_leaves = !self.cutout_leaves && state.leaves && other.leaves;
+                        let hollow_leaf = self.leaf_culling == LeafCullingMode::Hollow
+                            && state.leaves
+                            && other.leaves
+                            && leaf_culling::in_section(x + dx, y + dy, z + dz);
                         visible[d as usize] = !opaque_leaves
+                            && !hollow_leaf
                             && self
                                 .visibility
                                 .should_render_face(
@@ -1201,6 +1241,7 @@ impl Mesher<'_> {
                                 face,
                                 ao,
                                 state,
+                                interior_leaf,
                             );
                         }
                     }
@@ -1239,6 +1280,7 @@ impl Mesher<'_> {
         face: &BakedFace,
         ao: bool,
         state: &Info,
+        interior_leaf: bool,
     ) {
         let q = &face.quad;
         // A quad's own light (a model's glowing part) may raise the tier; whether it
@@ -1273,6 +1315,17 @@ impl Mesher<'_> {
         } else {
             &mut out.solid
         };
+        // Opaque leaves (forceOpaque), quads over opaque texels and leaves a
+        // leaf-culling mode proved internal draw in the solid layer: no alpha
+        // cutout. All four vertices of the quad share the layer.
+        let layer = if face.opaque && !face.translucent
+            || !self.cutout_leaves && state.leaves
+            || interior_leaf
+        {
+            face.layer as u16 | OPAQUE_LAYER
+        } else {
+            face.layer as u16
+        };
         for i in 0..4 {
             let g = gray[i] as u32;
             let rgb = match tint {
@@ -1283,13 +1336,7 @@ impl Mesher<'_> {
             target.push(TerrainVertex::new(
                 [p[0] + origin[0], p[1] + origin[1], p[2] + origin[2]],
                 q.uv[i],
-                // Opaque leaves (forceOpaque) and quads over opaque texels draw in the
-                // solid layer: no alpha cutout (a dirt path's side skips its clear top row).
-                if face.opaque && !face.translucent || !self.cutout_leaves && state.leaves {
-                    face.layer as u16 | OPAQUE_LAYER
-                } else {
-                    face.layer as u16
-                },
+                layer,
                 emitting(pack_rgb(rgb), tier),
                 pack_coords(lighting::with_emission(coords[i], q.light_emission)),
             ));

crates/horizon-client-render/src/mesher/leaf_culling.rs

@@ -0,0 +1,656 @@
+//! Leaf culling: decides which leaf faces a section may draw solid or drop.
+//!
+//! The mask is built on the mesh worker from the same padded block snapshot the
+//! rest of the mesher reads, so a decision never needs a chunk lookup on the
+//! render thread. It classifies each padded cell as a leaf, a full opaque cube,
+//! open (air, fluids, partial models, anything else) or unknown (a missing
+//! chunk, a Y outside the column, or the mask's outer shell). Only leaves can
+//! hide or solidify anything; unknown and open cells always expose a face.
+//!
+//! `Solid` performs an immediate 6-neighbour occlusion check, solidifying fully
+//! enclosed leaves into the opaque layer without cutout testing. `Solid
+//! Aggressive` runs a multi-source breadth-first search from leaves touching
+//! openings, solidifying leaves with a single open face to thin the canopy shell
+//! by one layer. `Hollow` directly drops faces shared between two leaves within
+//! the section, preserving boundaries and cavity faces.
+
+use super::{B, Info, P, Padded, pi};
+use crate::{blocks::RenderShape, chunk::Chunk, graphics::LeafCullingMode};
+
+/// A cell of the padded snapshot, as far as leaf culling cares.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub(super) enum Cell {
+    /// Air, a fluid, a partial model, glass or any other non-occluding block.
+    Open,
+    /// `LeavesBlock`.
+    Leaf,
+    /// A full opaque cube (see [`opaque_cube`]).
+    Opaque,
+    /// Missing chunk, missing section or the mask's outer shell.
+    Unknown,
+}
+
+/// Whether a state is a full opaque cube: `RenderShape::Model`, `can_occlude`,
+/// `solid_render` and a full collision shape. Glass, fluids, slabs, stairs,
+/// chests and models that only partly fill their block are not.
+pub(super) fn opaque_cube(
+    shape: RenderShape,
+    can_occlude: bool,
+    solid_render: bool,
+    full_collision: bool,
+) -> bool {
+    shape == RenderShape::Model && can_occlude && solid_render && full_collision
+}
+
+const UNVISITED: u8 = u8::MAX;
+
+const STRIDE_X: isize = 1;
+const STRIDE_Z: isize = P as isize;
+const STRIDE_Y: isize = (P * P) as isize;
+
+const ADJACENT_STRIDES: [isize; 6] = [
+    STRIDE_X, -STRIDE_X, STRIDE_Z, -STRIDE_Z, STRIDE_Y, -STRIDE_Y,
+];
+
+/// Per-worker leaf mask and BFS scratch. The vectors keep their capacity
+/// between sections and modes; `Off` does no work at all.
+#[derive(Default)]
+pub(super) struct LeafMask {
+    cells: Vec<Cell>,
+    depth: Vec<u8>,
+    queue: Vec<u16>,
+    active: bool,
+}
+
+impl LeafMask {
+    /// Classify the padded snapshot and, for the interior modes, measure how
+    /// deep each leaf sits below the canopy surface.
+    pub(super) fn prepare(
+        &mut self,
+        mode: LeafCullingMode,
+        pad: &Padded,
+        info: &[Info],
+        region: &[[Option<&Chunk>; 3]; 3],
+        base_y: i32,
+    ) {
+        self.active = mode != LeafCullingMode::Off;
+        if !self.active {
+            return;
+        }
+        // Most sections hold no leaves at all; do not classify 8,000 cells to
+        // learn that. The centre is the only part this mesh can change.
+        let mut leaves = false;
+        'scan: for y in 0..16 {
+            for z in 0..16 {
+                for x in 0..16 {
+                    if info
+                        .get(pad.blocks[pi(x, y, z)] as usize)
+                        .is_some_and(|state| state.leaves)
+                    {
+                        leaves = true;
+                        break 'scan;
+                    }
+                }
+            }
+        }
+        if !leaves {
+            self.active = false;
+            return;
+        }
+        if self.cells.len() != P * P * P {
+            self.cells.resize(P * P * P, Cell::Open);
+        }
+        for y in -B..16 + B {
+            for z in -B..16 + B {
+                for x in -B..16 + B {
+                    let i = pi(x, y, z);
+                    self.cells[i] = if !known(region, base_y, x, y, z) {
+                        Cell::Unknown
+                    } else {
+                        match info.get(pad.blocks[i] as usize) {
+                            None => Cell::Unknown,
+                            Some(state) if state.leaves => Cell::Leaf,
+                            Some(state) if state.opaque_cube => Cell::Opaque,
+                            Some(_) => Cell::Open,
+                        }
+                    };
+                }
+            }
+        }
+        // Solid is a purely local six-neighbour test. Reserve the breadth-first
+        // search for Solid Aggressive, whose one-open-side rule needs to know
+        // whether a leaf is connected to the canopy surface through other
+        // leaves.
+        if mode == LeafCullingMode::SolidAggressive {
+            self.depths();
+        }
+    }
+
+    /// Multi-source BFS from leaves that touch an opening. Opaque neighbours do
+    /// not expose a leaf: a leaf fully enclosed by stone is interior too.
+    fn depths(&mut self) {
+        if self.depth.len() != self.cells.len() {
+            self.depth.resize(self.cells.len(), UNVISITED);
+        } else {
+            self.depth.fill(UNVISITED);
+        }
+        self.queue.clear();
+        for y in -B..16 + B {
+            for z in -B..16 + B {
+                for x in -B..16 + B {
+                    let i = pi(x, y, z);
+                    if self.cells[i] != Cell::Leaf {
+                        continue;
+                    }
+                    let touches_open = ADJACENT_STRIDES.iter().any(|&stride| {
+                        let j = (i as isize + stride) as usize;
+                        matches!(self.cells[j], Cell::Open | Cell::Unknown)
+                    });
+                    if touches_open {
+                        self.depth[i] = 0;
+                        self.queue.push(i as u16);
+                    }
+                }
+            }
+        }
+        let mut head = 0;
+        while head < self.queue.len() {
+            let i = self.queue[head] as usize;
+            head += 1;
+            let next_depth = self.depth[i].saturating_add(1);
+            for stride in ADJACENT_STRIDES {
+                let j = (i as isize + stride) as usize;
+                if self.cells[j] == Cell::Leaf && self.depth[j] == UNVISITED {
+                    self.depth[j] = next_depth;
+                    self.queue.push(j as u16);
+                }
+            }
+        }
+    }
+
+    /// Whether the leaf at `(x, y, z)` may draw in the opaque layer.
+    ///
+    /// `Solid` wants a leaf with no open neighbour, which is exactly depth 1 or
+    /// more. `Solid Aggressive` also takes the next layer of the shell: a leaf
+    /// with a single open side joins the opaque core, so the cutout shell is
+    /// one layer thinner. Unknown neighbours never qualify, however many sides
+    /// they leave open. A leaf the search never reached sits inside a closed
+    /// volume: interior for both.
+    pub(super) fn interior(&self, mode: LeafCullingMode, x: i32, y: i32, z: i32) -> bool {
+        if !self.active {
+            return false;
+        }
+        let aggressive = match mode {
+            LeafCullingMode::Solid => false,
+            LeafCullingMode::SolidAggressive => true,
+            _ => return false,
+        };
+        // A section boundary is not proof of a closed volume: the neighbouring
+        // section may not be drawn yet, and its data is not ours to assume.
+        if !(1..15).contains(&x) || !(1..15).contains(&y) || !(1..15).contains(&z) {
+            return false;
+        }
+        let i = pi(x, y, z);
+        if self.cells.get(i) != Some(&Cell::Leaf) {
+            return false;
+        }
+        if !aggressive {
+            return ADJACENT_STRIDES.iter().all(|&stride| {
+                let j = (i as isize + stride) as usize;
+                matches!(self.cells[j], Cell::Leaf | Cell::Opaque)
+            });
+        }
+        let depth = self.depth[i];
+        if depth == UNVISITED || depth >= 1 {
+            return true;
+        }
+        let mut open = 0;
+        for stride in ADJACENT_STRIDES {
+            let j = (i as isize + stride) as usize;
+            match self.cells[j] {
+                Cell::Unknown => return false,
+                Cell::Open => {
+                    open += 1;
+                    if open > 1 {
+                        return false;
+                    }
+                }
+                Cell::Leaf | Cell::Opaque => {}
+            }
+        }
+        open == 1
+    }
+}
+
+/// The cells this section's mesh owns. A face on this boundary belongs to the
+/// neighbouring section as much as to this one; leaf culling leaves it alone.
+#[inline]
+pub(super) fn in_section(x: i32, y: i32, z: i32) -> bool {
+    (0..16).contains(&x) && (0..16).contains(&y) && (0..16).contains(&z)
+}
+
+/// Whether the padded cell `(x, y, z)` has real block data. A missing chunk
+/// does not count: `Padded::fill` copies the centre's edge column into it, which
+/// would make a canopy look enclosed. A Y outside the column counts as unknown
+/// for the same reason. The mask's outer shell is unknown too, so nothing is
+/// inferred past the data the worker snapshotted.
+fn known(region: &[[Option<&Chunk>; 3]; 3], base_y: i32, x: i32, y: i32, z: i32) -> bool {
+    if x <= -B || x >= 16 + B - 1 || y <= -B || y >= 16 + B - 1 || z <= -B || z >= 16 + B - 1 {
+        return false;
+    }
+    let chunk = region[((z + 16) >> 4) as usize][((x + 16) >> 4) as usize];
+    chunk.is_some_and(|chunk| chunk.section_index(base_y + y).is_some())
+}
+
+#[cfg(test)]
+impl LeafMask {
+    /// Whether `Hollow` drops the face of the leaf at `(x, y, z)` toward `d`.
+    /// Only a known leaf on the other side counts: open cells, partial models,
+    /// missing neighbours and the mask's edge stay visible.
+    pub(super) fn hides_face(
+        &self,
+        mode: LeafCullingMode,
+        x: i32,
+        y: i32,
+        z: i32,
+        d: horizon_core::geometry::Direction,
+    ) -> bool {
+        if !self.active || mode != LeafCullingMode::Hollow {
+            return false;
+        }
+        let [dx, dy, dz] = d.normal();
+        let (nx, ny, nz) = (x + dx, y + dy, z + dz);
+        if !in_section(x, y, z) || !in_section(nx, ny, nz) {
+            return false;
+        }
+        let i = pi(x, y, z);
+        let ni = pi(nx, ny, nz);
+        self.cells.get(i) == Some(&Cell::Leaf) && self.cells.get(ni) == Some(&Cell::Leaf)
+    }
+
+    #[inline]
+    fn cell(&self, x: i32, y: i32, z: i32) -> Cell {
+        checked(x, y, z)
+            .and_then(|i| self.cells.get(i))
+            .copied()
+            .unwrap_or(Cell::Unknown)
+    }
+}
+
+#[cfg(test)]
+#[inline]
+fn checked(x: i32, y: i32, z: i32) -> Option<usize> {
+    if (-B..16 + B).contains(&x) && (-B..16 + B).contains(&y) && (-B..16 + B).contains(&z) {
+        Some(pi(x, y, z))
+    } else {
+        None
+    }
+}
+
+#[cfg(test)]
+#[inline]
+fn unpi(i: usize) -> (i32, i32, i32) {
+    let x = (i % P) as i32 - B;
+    let z = (i / P % P) as i32 - B;
+    let y = (i / (P * P)) as i32 - B;
+    (x, y, z)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::{blocks::RenderShape, graphics::LeafCullingMode};
+    use horizon_core::geometry::Direction;
+    use horizon_world::fluid::FluidState;
+    use std::time::Instant;
+
+    fn info(leaves: bool, opaque: bool) -> Info {
+        Info {
+            solid: opaque,
+            full: opaque,
+            permeable: false,
+            shade: 1.0,
+            emission: 0,
+            tier: 0,
+            emissive: false,
+            fluid: FluidState::EMPTY,
+            model: true,
+            block_entity: false,
+            tints: [super::super::Tint::None; 2],
+            tint_count: 0,
+            offset: None,
+            legacy_solid: false,
+            overlay: leaves,
+            leaves,
+            opaque_cube: opaque,
+            blocks_flow: false,
+            ice: false,
+            sturdy: 0,
+            face: [0; 6],
+            cover: [0.0; 6],
+        }
+    }
+
+    /// State 0 is air, 1 leaves, 2 a full opaque cube, 3 a partial model.
+    fn states() -> Vec<Info> {
+        vec![
+            info(false, false),
+            info(true, false),
+            info(false, true),
+            info(false, false),
+        ]
+    }
+
+    fn padded(fill: impl Fn(i32, i32, i32) -> u32) -> Padded {
+        Padded {
+            blocks: (0..P * P * P)
+                .map(|i| {
+                    let (x, y, z) = unpi(i);
+                    fill(x, y, z)
+                })
+                .collect(),
+            light: vec![0; P * P * P],
+        }
+    }
+
+    fn cube(pad: &mut Padded, min: i32, max: i32, state: u32) {
+        for y in min..=max {
+            for z in min..=max {
+                for x in min..=max {
+                    pad.blocks[pi(x, y, z)] = state;
+                }
+            }
+        }
+    }
+
+    fn loaded() -> Chunk {
+        Chunk::empty(0, 0)
+    }
+
+    fn region(chunk: &Chunk) -> [[Option<&Chunk>; 3]; 3] {
+        [[Some(chunk); 3]; 3]
+    }
+
+    fn built(mode: LeafCullingMode, pad: &Padded, states: &[Info], chunk: &Chunk) -> LeafMask {
+        let mut mask = LeafMask::default();
+        mask.prepare(mode, pad, states, &region(chunk), 0);
+        mask
+    }
+
+    #[test]
+    fn only_a_full_model_cube_is_opaque() {
+        let combinations = [
+            (RenderShape::Model, true, true, true),
+            (RenderShape::Model, true, true, false),
+            (RenderShape::Model, true, false, true),
+            (RenderShape::Model, false, true, true),
+            (RenderShape::Model, false, false, false),
+            (RenderShape::Invisible, true, true, true),
+            (RenderShape::Animated, true, true, true),
+        ];
+        let (shape, can_occlude, solid_render, full_collision) = combinations[0];
+        assert!(opaque_cube(
+            shape,
+            can_occlude,
+            solid_render,
+            full_collision
+        ));
+        for &(shape, can_occlude, solid_render, full_collision) in &combinations[1..] {
+            assert!(
+                !opaque_cube(shape, can_occlude, solid_render, full_collision),
+                "{shape:?} {can_occlude} {solid_render} {full_collision}"
+            );
+        }
+    }
+
+    #[test]
+    fn solid_marks_the_cell_inside_a_three_cube() {
+        let states = states();
+        let mut pad = padded(|_, _, _| 0);
+        cube(&mut pad, 7, 9, 1);
+        let chunk = loaded();
+        let solid = built(LeafCullingMode::Solid, &pad, &states, &chunk);
+        assert!(!solid.interior(LeafCullingMode::Solid, 7, 8, 8));
+        assert!(solid.interior(LeafCullingMode::Solid, 8, 8, 8));
+        assert!(!solid.interior(LeafCullingMode::Solid, 8, 9, 8));
+        // Aggressive also takes the six face-centre leaves, whose only open
+        // side faces out of the cube. Corners and edges keep their cutout.
+        let aggressive = built(LeafCullingMode::SolidAggressive, &pad, &states, &chunk);
+        assert!(aggressive.interior(LeafCullingMode::SolidAggressive, 8, 8, 8));
+        assert!(aggressive.interior(LeafCullingMode::SolidAggressive, 7, 8, 8));
+        assert!(aggressive.interior(LeafCullingMode::SolidAggressive, 8, 8, 9));
+        assert!(!aggressive.interior(LeafCullingMode::SolidAggressive, 7, 7, 8));
+        assert!(!aggressive.interior(LeafCullingMode::SolidAggressive, 7, 7, 7));
+    }
+
+    #[test]
+    fn aggressive_takes_the_next_shell_layer() {
+        let states = states();
+        let mut pad = padded(|_, _, _| 0);
+        cube(&mut pad, 6, 10, 1);
+        let chunk = loaded();
+        let solid = built(LeafCullingMode::Solid, &pad, &states, &chunk);
+        let aggressive = built(LeafCullingMode::SolidAggressive, &pad, &states, &chunk);
+        let surface = |v: i32| v == 6 || v == 10;
+        for [x, y, z] in [
+            [6, 8, 8],
+            [10, 8, 8],
+            [6, 6, 8],
+            [6, 6, 6],
+            [7, 8, 8],
+            [8, 8, 8],
+            [7, 7, 7],
+            [8, 8, 7],
+        ] {
+            let expected = !surface(x) && !surface(y) && !surface(z);
+            assert_eq!(
+                solid.interior(LeafCullingMode::Solid, x, y, z),
+                expected,
+                "solid {x} {y} {z}"
+            );
+            let open = [x, y, z].iter().filter(|v| surface(**v)).count();
+            let expected = open <= 1;
+            assert_eq!(
+                aggressive.interior(LeafCullingMode::SolidAggressive, x, y, z),
+                expected,
+                "aggressive {x} {y} {z}"
+            );
+        }
+    }
+
+    #[test]
+    fn hollow_hides_only_leaf_to_leaf_faces() {
+        let states = states();
+        let mut pad = padded(|_, _, _| 0);
+        cube(&mut pad, 7, 9, 1);
+        // Glass (3, a partial model), water and a slab are open: their leaves
+        // must keep the face.
+        pad.blocks[pi(10, 8, 8)] = 3;
+        let chunk = loaded();
+        let hollow = built(LeafCullingMode::Hollow, &pad, &states, &chunk);
+        for d in Direction::ALL {
+            assert!(
+                hollow.hides_face(LeafCullingMode::Hollow, 8, 8, 8, d),
+                "{d:?}"
+            );
+        }
+        assert!(!hollow.hides_face(LeafCullingMode::Hollow, 9, 8, 8, Direction::East));
+        assert!(!hollow.hides_face(LeafCullingMode::Hollow, 7, 8, 8, Direction::West));
+        // The other modes never hide a quad.
+        for mode in [
+            LeafCullingMode::Off,
+            LeafCullingMode::Solid,
+            LeafCullingMode::SolidAggressive,
+        ] {
+            let mask = built(mode, &pad, &states, &chunk);
+            assert!(!mask.hides_face(mode, 8, 8, 8, Direction::Up));
+        }
+    }
+
+    #[test]
+    fn a_cavity_keeps_its_faces_and_its_rim_visible() {
+        let states = states();
+        let mut pad = padded(|_, _, _| 0);
+        cube(&mut pad, 6, 10, 1);
+        pad.blocks[pi(8, 8, 8)] = 0;
+        let chunk = loaded();
+        let hollow = built(LeafCullingMode::Hollow, &pad, &states, &chunk);
+        assert!(!hollow.hides_face(LeafCullingMode::Hollow, 7, 8, 8, Direction::East));
+        assert!(!hollow.hides_face(LeafCullingMode::Hollow, 8, 8, 7, Direction::South));
+        let solid = built(LeafCullingMode::Solid, &pad, &states, &chunk);
+        assert!(!solid.interior(LeafCullingMode::Solid, 7, 8, 8));
+        assert!(!solid.interior(LeafCullingMode::Solid, 6, 8, 8));
+        // The corner away from the cavity is still two layers in.
+        assert!(solid.interior(LeafCullingMode::Solid, 9, 9, 9));
+    }
+
+    #[test]
+    fn an_opaque_neighbour_does_not_expose_a_leaf() {
+        let states = states();
+        let mut pad = padded(|_, _, _| 0);
+        for (dx, dy, dz) in [
+            (1, 0, 0),
+            (-1, 0, 0),
+            (0, 1, 0),
+            (0, -1, 0),
+            (0, 0, 1),
+            (0, 0, -1),
+        ] {
+            pad.blocks[pi(8 + dx, 8 + dy, 8 + dz)] = 2;
+        }
+        pad.blocks[pi(8, 8, 8)] = 1;
+        let chunk = loaded();
+        for mode in [LeafCullingMode::Solid, LeafCullingMode::SolidAggressive] {
+            let mask = built(mode, &pad, &states, &chunk);
+            assert!(mask.interior(mode, 8, 8, 8), "{mode:?}");
+        }
+        let hollow = built(LeafCullingMode::Hollow, &pad, &states, &chunk);
+        for d in Direction::ALL {
+            assert!(
+                !hollow.hides_face(LeafCullingMode::Hollow, 8, 8, 8, d),
+                "{d:?}"
+            );
+        }
+    }
+
+    #[test]
+    fn a_leaf_inside_a_closed_volume_is_interior() {
+        let states = states();
+        // A leaf cube inside opaque rock: the search has no opening to start
+        // from, so every leaf stays unvisited and counts as interior.
+        let mut pad = padded(|_, _, _| 2);
+        cube(&mut pad, 7, 9, 1);
+        let chunk = loaded();
+        for mode in [LeafCullingMode::Solid, LeafCullingMode::SolidAggressive] {
+            let mask = built(mode, &pad, &states, &chunk);
+            if mode == LeafCullingMode::SolidAggressive {
+                assert_eq!(mask.depth[pi(8, 8, 8)], UNVISITED);
+            }
+            assert!(mask.interior(mode, 8, 8, 8), "{mode:?}");
+        }
+    }
+
+    #[test]
+    fn missing_chunks_and_sections_are_unknown() {
+        let states = states();
+        let pad = padded(|_, _, _| 1);
+        let chunk = loaded();
+        let mut around = [[Some(&chunk); 3]; 3];
+        around[1][2] = None; // east chunk
+        let mut mask = LeafMask::default();
+        mask.prepare(LeafCullingMode::Hollow, &pad, &states, &around, 0);
+        // The leaf at the edge keeps its face toward the missing chunk, even
+        // though `Padded::fill` copied the centre's edge leaf there.
+        assert!(!mask.hides_face(LeafCullingMode::Hollow, 15, 8, 8, Direction::East));
+        // A leaf one block inside is still between two known leaves.
+        assert!(mask.hides_face(LeafCullingMode::Hollow, 14, 8, 8, Direction::East));
+
+        // A section above the column is unknown too: the same leaf one
+        // section up has no data, so it can never be interior.
+        let short = Chunk::with_layout(0, 0, crate::chunk::ColumnLayout::new(0, 16).unwrap());
+        let mut mask = LeafMask::default();
+        mask.prepare(LeafCullingMode::Solid, &pad, &states, &region(&short), 16);
+        assert!(!mask.interior(LeafCullingMode::Solid, 8, 8, 8));
+
+        // The outer shell has no data beyond it.
+        let mut mask = LeafMask::default();
+        mask.prepare(LeafCullingMode::Hollow, &pad, &states, &region(&chunk), 0);
+        assert_eq!(mask.cell(-B, 0, 0), Cell::Unknown);
+        assert_eq!(mask.cell(16 + B - 1, 0, 0), Cell::Unknown);
+        assert_eq!(mask.cell(0, 0, 0), Cell::Leaf);
+
+        // A section boundary is never enclosed, even with every chunk loaded:
+        // the neighbouring section may not have been meshed yet.
+        let mut mask = LeafMask::default();
+        mask.prepare(LeafCullingMode::Solid, &pad, &states, &region(&chunk), 0);
+        assert!(!mask.interior(LeafCullingMode::Solid, 15, 8, 8));
+        assert!(mask.interior(LeafCullingMode::Solid, 14, 8, 8));
+    }
+
+    #[test]
+    fn off_does_no_work_and_hides_nothing() {
+        let states = states();
+        let mut pad = padded(|_, _, _| 0);
+        cube(&mut pad, 7, 9, 1);
+        let chunk = loaded();
+        let mut mask = LeafMask::default();
+        mask.prepare(LeafCullingMode::Off, &pad, &states, &region(&chunk), 0);
+        assert!(!mask.active);
+        assert!(mask.cells.is_empty());
+        assert!(!mask.interior(LeafCullingMode::Off, 8, 8, 8));
+        assert!(!mask.hides_face(LeafCullingMode::Off, 8, 8, 8, Direction::Up));
+    }
+
+    #[test]
+    fn a_reused_mask_reclassifies_every_cell() {
+        let states = states();
+        let chunk = loaded();
+        let mut mask = LeafMask::default();
+        let mut leaves = padded(|_, _, _| 0);
+        cube(&mut leaves, 7, 9, 1);
+        mask.prepare(
+            LeafCullingMode::Hollow,
+            &leaves,
+            &states,
+            &region(&chunk),
+            0,
+        );
+        assert_eq!(mask.cell(8, 8, 8), Cell::Leaf);
+        let mut other = padded(|_, _, _| 0);
+        cube(&mut other, 10, 12, 1);
+        mask.prepare(LeafCullingMode::Hollow, &other, &states, &region(&chunk), 0);
+        assert_eq!(mask.cell(8, 8, 8), Cell::Open);
+        assert_eq!(mask.cell(11, 11, 11), Cell::Leaf);
+    }
+
+    #[test]
+    #[ignore = "microbenchmark; run with --ignored --nocapture"]
+    fn mask_build_benchmark() {
+        let states = states();
+        let mut pad = padded(|x, y, z| {
+            // Alternating leaf slabs make the search visit most of the volume.
+            if (x / 2 + y / 2 + z / 2) % 3 == 0 {
+                1
+            } else {
+                0
+            }
+        });
+        cube(&mut pad, 6, 10, 1);
+        let chunk = loaded();
+        let region = region(&chunk);
+        let iterations = 1000;
+        for mode in [LeafCullingMode::Solid, LeafCullingMode::SolidAggressive] {
+            let mut mask = LeafMask::default();
+            let started = Instant::now();
+            for _ in 0..iterations {
+                mask.prepare(mode, &pad, &states, &region, 0);
+            }
+            let per = started.elapsed() / iterations;
+            println!("leaf mask {mode:?}: {per:?} per section ({iterations} iterations)");
+            assert!(mask.active);
+            if mode == LeafCullingMode::SolidAggressive {
+                assert_ne!(mask.depth[pi(8, 8, 8)], UNVISITED);
+            }
+        }
+    }
+}

crates/horizon-client-render/src/mesher/leaf_culling_tests.rs

@@ -0,0 +1,293 @@
+//! Leaf culling through the real mesher: face counts, the opaque layer and the
+//! conservative cases (cavities, partial neighbours, missing chunks, column
+//! ends). Needs prepared resources, like the other mesher geometry tests.
+use super::*;
+use crate::{
+    assets::{Assets, RenderAssets},
+    biome::Biomes,
+    blocks::BlockFacts,
+    chunk::{Chunk, ColumnLayout},
+    graphics::LeafCullingMode,
+    models,
+};
+
+struct Fixture {
+    assets: Assets,
+    biomes: Biomes,
+    render: RenderAssets,
+    visibility: horizon_world::block_render::FaceVisibility,
+    tables: MeshTables,
+}
+
+fn fixture() -> Fixture {
+    let root = std::env::var_os("HORIZON_MESH_TEST_RESOURCES")
+        .map(std::path::PathBuf::from)
+        .unwrap_or_else(|| {
+            std::path::Path::new(env!("CARGO_MANIFEST_DIR"))
+                .join("../../.local/horizon-client/26.3")
+        });
+    let assets = Assets::load(&root).unwrap();
+    let facts = BlockFacts::load(&root, assets.registry).unwrap();
+    let biomes = Biomes::load(&root).unwrap();
+    let render = assets.reload(&root).unwrap();
+    let visibility = models::load_visibility(&root, assets.registry).unwrap();
+    let tables = MeshTables::new(&assets, &render, &facts, visibility.clone()).unwrap();
+    Fixture {
+        assets,
+        biomes,
+        render,
+        visibility,
+        tables,
+    }
+}
+
+fn state(f: &Fixture, name: &str) -> u32 {
+    f.assets.registry.default_state(name).unwrap().0
+}
+
+fn leaves_cube(chunk: &mut Chunk, min: i32, max: i32, y: i32, state: u32) {
+    for z in min..=max {
+        for x in min..=max {
+            chunk.set(x, y, z, state);
+        }
+    }
+}
+
+fn leaf_cube(f: &Fixture, min: i32, max: i32, base: i32, name: &str) -> Chunk {
+    let mut chunk = Chunk::empty(0, 0);
+    let state = state(f, name);
+    for y in base..base + (max - min + 1) {
+        leaves_cube(&mut chunk, min, max, y, state);
+    }
+    chunk
+}
+
+fn mesh(
+    f: &Fixture,
+    _chunk: &Chunk,
+    region: [[Option<&Chunk>; 3]; 3],
+    sy: i32,
+    mode: LeafCullingMode,
+) -> SectionMesh {
+    let mut mesher = Mesher {
+        nether_shading: false,
+        shader_pack_lighting: false,
+        assets: &f.assets,
+        render: &f.render,
+        tables: &f.tables,
+        biomes: &f.biomes,
+        visibility: f.visibility.clone(),
+        zoom: BiomeZoom::new(0),
+        blend_radius: 0,
+        smooth_lighting: false,
+        cutout_leaves: true,
+        leaf_culling: mode,
+    };
+    mesher.mesh(&region, sy)
+}
+
+fn around(chunk: &Chunk) -> [[Option<&Chunk>; 3]; 3] {
+    [[Some(chunk); 3]; 3]
+}
+
+/// (opaque, cutout) leaf quads, rejecting a quad whose four vertices disagree.
+fn quads(mesh: &SectionMesh) -> (usize, usize) {
+    let mut opaque = 0;
+    let mut cutout = 0;
+    for quad in mesh.solid.as_chunks::<4>().0 {
+        let flags = quad
+            .iter()
+            .map(|v| v.layer & OPAQUE_LAYER != 0)
+            .collect::<Vec<_>>();
+        assert!(
+            flags.iter().all(|flag| *flag == flags[0]),
+            "a quad mixed opaque and cutout vertices: {flags:?}"
+        );
+        if flags[0] {
+            opaque += 1;
+        } else {
+            cutout += 1;
+        }
+    }
+    assert_eq!(mesh.solid.len() % 4, 0);
+    (opaque, cutout)
+}
+
+const BASE: i32 = MIN_Y + 4;
+
+#[test]
+#[ignore = "requires prepared 26.3 resources (HORIZON_MESH_TEST_RESOURCES or .local/horizon-client/26.3)"]
+fn off_draws_every_fancy_leaf_face() {
+    let f = fixture();
+    let chunk = leaf_cube(&f, 6, 8, BASE, "minecraft:oak_leaves");
+    let mesh = mesh(&f, &chunk, around(&chunk), 0, LeafCullingMode::Off);
+    // 27 blocks, six quads each: vanilla's fancy leaves keep the inside.
+    assert_eq!(quads(&mesh), (0, 162));
+    assert_eq!(mesh.translucent.len(), 0);
+}
+
+#[test]
+#[ignore = "requires prepared 26.3 resources (HORIZON_MESH_TEST_RESOURCES or .local/horizon-client/26.3)"]
+fn solid_draws_the_fully_enclosed_leaf_opaque() {
+    let f = fixture();
+    let chunk = leaf_cube(&f, 6, 8, BASE, "minecraft:oak_leaves");
+    let solid = mesh(&f, &chunk, around(&chunk), 0, LeafCullingMode::Solid);
+    // Only the centre has all six sides covered: its six quads go opaque.
+    assert_eq!(quads(&solid), (6, 156));
+
+    let aggressive = mesh(
+        &f,
+        &chunk,
+        around(&chunk),
+        0,
+        LeafCullingMode::SolidAggressive,
+    );
+    // Aggressive also takes the six face-centre leaves: seven blocks opaque.
+    assert_eq!(quads(&aggressive), (42, 120));
+}
+
+#[test]
+#[ignore = "requires prepared 26.3 resources (HORIZON_MESH_TEST_RESOURCES or .local/horizon-client/26.3)"]
+fn aggressive_solidifies_the_next_shell_layer_of_a_five_cube() {
+    let f = fixture();
+    let chunk = leaf_cube(&f, 5, 9, BASE, "minecraft:oak_leaves");
+    let solid = mesh(&f, &chunk, around(&chunk), 0, LeafCullingMode::Solid);
+    // The 3x3x3 inside the surface: 27 blocks, six quads each.
+    assert_eq!(quads(&solid), (162, 588));
+    let aggressive = mesh(
+        &f,
+        &chunk,
+        around(&chunk),
+        0,
+        LeafCullingMode::SolidAggressive,
+    );
+    // The 3x3x3 inside plus the 3x3 face centre of each of the six sides.
+    assert_eq!(quads(&aggressive), (486, 264));
+}
+
+#[test]
+#[ignore = "requires prepared 26.3 resources (HORIZON_MESH_TEST_RESOURCES or .local/horizon-client/26.3)"]
+fn hollow_drops_only_the_faces_two_leaves_share() {
+    let f = fixture();
+    let chunk = leaf_cube(&f, 6, 8, BASE, "minecraft:oak_leaves");
+    let hollow = mesh(&f, &chunk, around(&chunk), 0, LeafCullingMode::Hollow);
+    // 162 quads minus the 54 shared pairs' 108 faces: the 3x3x3 shell.
+    assert_eq!(quads(&hollow), (0, 54));
+}
+
+#[test]
+#[ignore = "requires prepared 26.3 resources (HORIZON_MESH_TEST_RESOURCES or .local/horizon-client/26.3)"]
+fn mixed_species_count_as_one_leaf_volume() {
+    let f = fixture();
+    let oak = state(&f, "minecraft:oak_leaves");
+    let birch = state(&f, "minecraft:birch_leaves");
+    let mut chunk = Chunk::empty(0, 0);
+    for y in BASE..BASE + 3 {
+        for z in 6..=8 {
+            for x in 6..=8 {
+                chunk.set(x, y, z, if (x + y + z) % 2 == 0 { oak } else { birch });
+            }
+        }
+    }
+    let solid = mesh(&f, &chunk, around(&chunk), 0, LeafCullingMode::Solid);
+    assert_eq!(quads(&solid), (6, 156));
+    let hollow = mesh(&f, &chunk, around(&chunk), 0, LeafCullingMode::Hollow);
+    assert_eq!(quads(&hollow), (0, 54));
+}
+
+#[test]
+#[ignore = "requires prepared 26.3 resources (HORIZON_MESH_TEST_RESOURCES or .local/horizon-client/26.3)"]
+fn a_cavity_keeps_its_six_faces_and_its_rim_stays_cutout() {
+    let f = fixture();
+    let mut chunk = leaf_cube(&f, 5, 9, BASE, "minecraft:oak_leaves");
+    chunk.set(7, BASE + 2, 7, 0);
+    let hollow = mesh(&f, &chunk, around(&chunk), 0, LeafCullingMode::Hollow);
+    // Five-cube shell (150) plus the six faces around the one-block cavity.
+    assert_eq!(quads(&hollow), (0, 156));
+    let solid = mesh(&f, &chunk, around(&chunk), 0, LeafCullingMode::Solid);
+    // The six leaves around the cavity are exposed, so they stay cutout; the
+    // other 20 inner leaves draw solid. The cavity block itself has no quads.
+    assert_eq!(quads(&solid), (120, 624));
+}
+
+#[test]
+#[ignore = "requires prepared 26.3 resources (HORIZON_MESH_TEST_RESOURCES or .local/horizon-client/26.3)"]
+fn section_boundary_faces_stay_with_a_loaded_neighbour() {
+    let f = fixture();
+    let leaf = state(&f, "minecraft:oak_leaves");
+    let chunk = leaf_cube(&f, 12, 15, BASE, "minecraft:oak_leaves");
+    // A loaded east chunk whose x=0 column continues the canopy.
+    let mut east = Chunk::empty(1, 0);
+    for y in BASE..BASE + 4 {
+        for z in 12..=15 {
+            east.set(0, y, z, leaf);
+        }
+    }
+    let mut region = around(&chunk);
+    region[1][2] = Some(&east);
+    let joined = mesh(&f, &chunk, region, 0, LeafCullingMode::Hollow);
+    let mut region = around(&chunk);
+    region[1][2] = None;
+    let missing = mesh(&f, &chunk, region, 0, LeafCullingMode::Hollow);
+    // The east faces of the x=15 leaves are on the section boundary: a loaded
+    // neighbour does not let Hollow drop them, and a missing one does not
+    // change the mesh either.
+    assert_eq!(joined.solid.len(), missing.solid.len());
+    let off = mesh(&f, &chunk, around(&chunk), 0, LeafCullingMode::Off);
+    assert!(joined.solid.len() < off.solid.len());
+}
+
+#[test]
+#[ignore = "requires prepared 26.3 resources (HORIZON_MESH_TEST_RESOURCES or .local/horizon-client/26.3)"]
+fn the_top_of_a_one_section_column_stays_visible() {
+    let f = fixture();
+    let leaf = state(&f, "minecraft:oak_leaves");
+    let layout = ColumnLayout::new(0, 16).unwrap();
+    let mut chunk = Chunk::with_layout(0, 0, layout);
+    for y in 13..16 {
+        leaves_cube(&mut chunk, 5, 7, y, leaf);
+    }
+    let hollow = mesh(&f, &chunk, around(&chunk), 0, LeafCullingMode::Hollow);
+    let solid = mesh(&f, &chunk, around(&chunk), 0, LeafCullingMode::Solid);
+    // y=15 is the column's top: the faces toward y=16 are unknown, so they
+    // stay, and the y=15 leaves are not enclosed.
+    assert!(!hollow.solid.is_empty());
+    assert!(solid.solid.iter().any(|v| v.pos[1] == 16.0));
+    assert!(
+        solid
+            .solid
+            .iter()
+            .filter(|v| v.pos[1] == 16.0)
+            .all(|v| v.layer & OPAQUE_LAYER == 0)
+    );
+}
+
+#[test]
+#[ignore = "requires prepared 26.3 resources (HORIZON_MESH_TEST_RESOURCES or .local/horizon-client/26.3)"]
+fn a_world_without_leaves_meshes_identically_in_every_mode() {
+    let f = fixture();
+    let mut chunk = Chunk::empty(0, 0);
+    for y in BASE..BASE + 3 {
+        leaves_cube(&mut chunk, 6, 8, y, state(&f, "minecraft:stone"));
+    }
+    let off = mesh(&f, &chunk, around(&chunk), 0, LeafCullingMode::Off);
+    for mode in LeafCullingMode::ALL {
+        let other = mesh(&f, &chunk, around(&chunk), 0, mode);
+        assert_eq!(off.solid.len(), other.solid.len(), "{mode:?}");
+        assert_eq!(off.translucent.len(), other.translucent.len(), "{mode:?}");
+        for (a, b) in off.solid.iter().zip(&other.solid) {
+            assert_eq!(
+                (a.pos, a.uv, a.layer, a.light, a.color),
+                (b.pos, b.uv, b.layer, b.light, b.color),
+                "{mode:?}"
+            );
+        }
+        for (a, b) in off.translucent.iter().zip(&other.translucent) {
+            assert_eq!(
+                (a.pos, a.uv, a.layer, a.light, a.color),
+                (b.pos, b.uv, b.layer, b.light, b.color),
+                "{mode:?}"
+            );
+        }
+    }
+}

crates/horizon-client-render/src/mesher/reuse_tests.rs

@@ -81,6 +81,7 @@ fn a_shader_pack_lights_the_faces_itself() {
             blend_radius: 0,
             smooth_lighting: false,
             cutout_leaves: true,
+            leaf_culling: LeafCullingMode::Off,
         };
         let mut colours: Vec<u32> = mesher
             .mesh(&region, 0)
@@ -156,6 +157,7 @@ fn reused_mesh_matches_fresh_geometry_across_sections_and_resource_reload() {
             blend_radius: 2,
             smooth_lighting: reload == 0,
             cutout_leaves: reload == 0,
+            leaf_culling: LeafCullingMode::Off,
         };
         for (case, (center, east)) in [
             (&empty, None),

crates/horizon-client-render/src/mesher/visibility_tests.rs

@@ -88,6 +88,7 @@ fn info(solid: bool) -> Info {
         legacy_solid: false,
         overlay: false,
         leaves: false,
+        opaque_cube: solid,
         blocks_flow: false,
         ice: false,
         sturdy: 0,

crates/horizon-client-render/src/options_ui.rs

@@ -1264,6 +1264,8 @@ pub enum Page {
     Online,
     /// Splitscreen: the profile another player joins as (`split_profiles`).
     SplitProfiles,
+    /// Splitscreen: enable joining on this computer.
+    SplitSetup,
 }
 #[derive(Clone, Debug, PartialEq)]
 enum Act {
@@ -1526,6 +1528,8 @@ pub struct OptionsUi {
     /// The list's rows as last laid out: each row's top and bottom (GUI
     /// pixels), for the narration's row under the mouse.
     row_bands: Vec<[f32; 2]>,
+    /// Other local players are joined: leave before turning splitscreen off.
+    pub split_joined: bool,
 }
 impl Default for OptionsUi {
     fn default() -> Self {
@@ -1571,6 +1575,7 @@ impl Default for OptionsUi {
             framebuffer: [1280, 720],
             split_guest: false,
             row_bands: Vec::new(),
+            split_joined: false,
         }
     }
 }
@@ -1634,6 +1639,7 @@ fn horizon_page_tooltip(page: Page) -> Option<&'static str> {
         Page::SplitProfiles => "horizon.pages.split_profiles.tooltip",
         Page::ShaderPacks => "horizon.pages.shader_packs.tooltip",
         Page::Mods => "horizon.pages.mods.tooltip",
+        Page::SplitSetup => "horizon.pages.split_setup.tooltip",
         _ => return None,
     })
 }
@@ -2166,6 +2172,7 @@ impl OptionsUi {
             Page::Horizon => "horizon.pages.settings",
             Page::Agent => "horizon.pages.agent",
             Page::SplitProfiles => "horizon.pages.split_profiles",
+            Page::SplitSetup => "horizon.pages.split_setup",
         }
     }
     fn scrollbar_x(&self, width: f32) -> f32 {
@@ -2255,6 +2262,14 @@ impl OptionsUi {
 
     fn list_rows(&self, s: &Settings) -> Vec<Row> {
         match self.page() {
+            Page::SplitSetup => vec![Row::Buttons(
+                if self.split_guest || self.split_joined {
+                    inactive(self.extra_button(s, crate::extras::Item::Splitscreen))
+                } else {
+                    self.extra_button(s, crate::extras::Item::Splitscreen)
+                },
+                None,
+            )],
             Page::Extras => {
                 // Each section's switches two to a row, as vanilla's
                 // OptionsList.addSmall lays out an options screen.
@@ -2321,6 +2336,17 @@ impl OptionsUi {
                         open("horizon.pages.open.extras", Page::Extras),
                         Some(open("horizon.pages.open.mods", Page::Mods)),
                     ),
+                    Row::Buttons(
+                        open(
+                            "horizon.pages.open.split_setup",
+                            if self.split_guest {
+                                Page::SplitProfiles
+                            } else {
+                                Page::SplitSetup
+                            },
+                        ),
+                        None,
+                    ),
                     // No AI hides the AI Agent page and everything AI.
                     Row::Buttons(
                         self.extra_button(s, crate::extras::Item::DiscordPresence),
@@ -6788,6 +6814,7 @@ mod tests {
                 Page::Controller,
                 Page::Extras,
                 Page::Mods,
+                Page::SplitSetup,
                 Page::Agent,
             ]
         );

crates/horizon-client-render/src/post_chain.rs

@@ -1024,6 +1024,7 @@ impl PostEffects {
         size: [u32; 2],
         depth: Option<&wgpu::TextureView>,
         req: &Request,
+        mut timing: Option<&mut crate::gfx::pack_timing::PassTiming>,
     ) -> bool {
         self.use_root(req.root);
         let mut applied = Vec::new();
@@ -1099,6 +1100,7 @@ impl PostEffects {
             (&work.1, size),
             0.0,
             format,
+            timing.as_deref_mut(),
         );
         self.staging = Some(staging);
         for id in &applied {
@@ -1113,6 +1115,7 @@ impl PostEffects {
                 depth,
                 req.menu_blur_radius,
                 format,
+                timing.as_deref_mut(),
             );
             self.chains.insert(id.clone(), Some(chain));
         }
@@ -1126,6 +1129,7 @@ impl PostEffects {
             (target, size),
             0.0,
             format,
+            timing,
         );
         self.blit = Some(blit);
         self.work = Some(work);
@@ -1144,6 +1148,7 @@ impl PostEffects {
         main_depth: Option<&wgpu::TextureView>,
         menu_radius: f32,
         format: wgpu::TextureFormat,
+        mut timing: Option<&mut crate::gfx::pack_timing::PassTiming>,
     ) {
         for pass in &mut chain.passes {
             if let Some(translated) = &mut pass.translated {
@@ -1203,6 +1208,7 @@ impl PostEffects {
             {
                 encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
                     label: Some("Post effect depth clear"),
+                    timestamp_writes: timing.as_deref_mut().and_then(|t| t.writes("Post clear")),
                     color_attachments: &[],
                     depth_stencil_attachment: Some(wgpu::RenderPassDepthStencilAttachment {
                         view,
@@ -1221,6 +1227,7 @@ impl PostEffects {
                 let c = t.clear.map(f64::from);
                 encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
                     label: Some("Post effect target clear"),
+                    timestamp_writes: timing.as_deref_mut().and_then(|t| t.writes("Post clear")),
                     color_attachments: &[Some(wgpu::RenderPassColorAttachment {
                         view: &chain.textures[i - 1].1,
                         resolve_target: None,
@@ -1274,6 +1281,7 @@ impl PostEffects {
                     &inputs,
                     (view(pass.output), sizes[pass.output]),
                     format,
+                    timing.as_deref_mut(),
                 );
                 continue;
             }
@@ -1287,6 +1295,7 @@ impl PostEffects {
                 (view(pass.output), sizes[pass.output]),
                 menu_radius,
                 format,
+                timing.as_deref_mut(),
             );
         }
     }
@@ -1303,6 +1312,7 @@ impl PostEffects {
         inputs: &[(&wgpu::TextureView, [u32; 2])],
         output: (&wgpu::TextureView, [u32; 2]),
         format: wgpu::TextureFormat,
+        timing: Option<&mut crate::gfx::pack_timing::PassTiming>,
     ) {
         let Some(pipeline) = translated.pipelines.get(&format) else {
             return;
@@ -1353,6 +1363,7 @@ impl PostEffects {
         });
         let mut rp = encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
             label: Some("Post effect pass"),
+            timestamp_writes: timing.and_then(|t| t.writes("Post effect")),
             color_attachments: &[Some(wgpu::RenderPassColorAttachment {
                 view: output.0,
                 resolve_target: None,
@@ -1381,6 +1392,7 @@ impl PostEffects {
         output: (&wgpu::TextureView, [u32; 2]),
         menu_radius: f32,
         format: wgpu::TextureFormat,
+        timing: Option<&mut crate::gfx::pack_timing::PassTiming>,
     ) {
         // SamplerInfo: OutSize, then each input's size.
         let info = [
@@ -1441,6 +1453,7 @@ impl PostEffects {
         });
         let mut rp = encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
             label: Some("Post effect pass"),
+            timestamp_writes: timing.and_then(|t| t.writes("Post effect")),
             color_attachments: &[Some(wgpu::RenderPassColorAttachment {
                 view: output.0,
                 resolve_target: None,
@@ -1715,6 +1728,7 @@ mod tests {
                 menu_blur_radius: 5.0,
                 globals: Globals::default(),
             },
+            None,
         );
         let buffer = crate::gfx::copy_frame(device, &mut encoder, &frame, [8, 4]);
         queue.submit([encoder.finish()]);
@@ -1845,6 +1859,7 @@ mod tests {
                 menu_blur_radius: 0.0,
                 globals: Globals::default(),
             },
+            None,
         ));
         let buffer = crate::gfx::copy_frame(device, &mut encoder, &frame, [8, 4]);
         queue.submit([encoder.finish()]);

crates/horizon-client-render/src/settings.rs

@@ -341,9 +341,10 @@ impl Settings {
             .parent()
             .map(crate::extras::Extras::load)
             .unwrap_or_default();
+        // The enabled mods are the game folder's, shared by its players (`--player-dir`).
         let mods = path
             .parent()
-            .map(crate::mod_list::ModList::load)
+            .map(|dir| crate::mod_list::ModList::load(&crate::logging::shared_dir(dir)))
             .unwrap_or_default();
         let settings = match fs::read(path) {
             Ok(bytes) => Self {
@@ -650,7 +651,7 @@ impl Settings {
             self.horizon.save(dir);
             self.controller.save(dir);
             self.extras.save(dir);
-            self.mods.save(dir);
+            self.mods.save(&crate::logging::shared_dir(dir));
         }
     }
     /// Volume of a sound source (master excluded).

crates/horizon-client-render/src/sound_engine.rs

@@ -25,6 +25,9 @@ pub const UI: usize = 10;
 /// sources: `clamp((int) sqrt(255), 2, 8)` streaming, the rest static.
 pub const STATIC_CHANNELS: usize = 247;
 pub const STREAMING_CHANNELS: usize = 8;
+/// Static channels only sounds played to the listener (no position) may take
+/// while the `uiSoundReserve` extra is on.
+pub const HEARD_RESERVE: usize = 16;
 
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub enum PlayResult {
@@ -65,6 +68,9 @@ pub enum Ticking {
     /// `RidingEntitySoundInstance` for the player riding a happy ghast
     /// (`underwater_sound` false) or a nautilus (true).
     RidingEntity { entity: u32, underwater_sound: bool },
+    /// A native mod's music layer (`MusicLayers`), whose volume its owner
+    /// sets each tick.
+    MusicLayer,
 }
 /// What a minecart's sound instances read about it.
 #[derive(Clone, Copy, Debug)]
@@ -230,6 +236,25 @@ impl SoundInstance {
             true,
         )
     }
+    /// A native mod's music layer: a looping, unattenuated track on the music
+    /// source that starts silent (`MusicLayers` fades it in).
+    pub fn for_music_layer(id: &str, random: LegacyRandom) -> Self {
+        let mut s = Self::new(
+            id,
+            MUSIC,
+            0.0,
+            1.0,
+            random,
+            true,
+            0,
+            Attenuation::None,
+            [0.0; 3],
+            true,
+        );
+        s.can_start_silent = true;
+        s.ticking = Ticking::MusicLayer;
+        s
+    }
     /// `SimpleSoundInstance.forJukeboxSong`.
     pub fn for_jukebox_song(id: &str, at: [f64; 3], random: LegacyRandom) -> Self {
         Self::new(
@@ -519,7 +544,7 @@ impl SoundInstance {
     /// `TickableSoundInstance.tick`.
     pub fn tick(&mut self, ctx: &TickContext) {
         match &mut self.ticking {
-            Ticking::No => {}
+            Ticking::No | Ticking::MusicLayer => {}
             Ticking::BiomeLoop { fade, direction } => {
                 let stop = *fade < 0;
                 *fade += *direction;
@@ -792,6 +817,9 @@ pub struct SoundEngine {
     pub source_volumes: [f32; 11],
     /// A `SoundEventListener` is registered.
     pub listening: bool,
+    /// Static channels positional sounds leave free for the ones played to the
+    /// listener: 0 as vanilla, `HEARD_RESERVE` with the `uiSoundReserve` extra.
+    pub listener_reserve: usize,
     pub notifications: Vec<Notification>,
 }
 fn handle_channel(h: &Handle) -> Option<ChannelId> {
@@ -819,6 +847,7 @@ impl SoundEngine {
             limits: [STATIC_CHANNELS, STREAMING_CHANNELS],
             source_volumes: [1.0; 11],
             listening: false,
+            listener_reserve: 0,
             notifications: Vec::new(),
         }
     }
@@ -1100,7 +1129,15 @@ impl SoundEngine {
         let looping = instance.looping && instance.delay <= 0;
         let streaming = sound.stream;
         let pool = usize::from(streaming);
-        let channel = if self.used[pool] >= self.limits[pool] {
+        // With the `uiSoundReserve` extra, sounds out in the world leave a few static channels free, so a flood of
+        // them (a crater's worth of blocks breaking) can't stop the ones played to the listener.
+        let positional = !instance.relative && instance.attenuation != Attenuation::None;
+        let reserved = if positional && !streaming {
+            self.listener_reserve
+        } else {
+            0
+        };
+        let channel = if self.used[pool] + reserved >= self.limits[pool] {
             None
         } else {
             backend.create(streaming)
@@ -1549,4 +1586,47 @@ mod tests {
         assert_eq!(s.volume, 0.0);
         assert!(!s.stopped);
     }
+    #[test]
+    fn world_sounds_leave_channels_for_the_listener_only_with_the_extra() {
+        use test_backend::Null;
+        let mut registry = SoundRegistry::default();
+        registry.add_file(
+            "minecraft",
+            br#"{"block.stone.break": {"sounds": ["dig/stone1"]},
+                 "ui.button.click": {"sounds": ["random/click"]}}"#,
+            &|_, _| true,
+        );
+        let random = || LegacyRandom::new(0);
+        let block = |i: usize| {
+            let at = [i as f64, 64.0, 0.0];
+            let source = crate::settings::sound_source("minecraft:block.stone.break");
+            SoundInstance::at(
+                "minecraft:block.stone.break",
+                source,
+                1.0,
+                1.0,
+                random(),
+                at,
+            )
+        };
+        let click = || SoundInstance::for_ui("minecraft:ui.button.click", 1.0, 0.25, random());
+        for reserve in [0, HEARD_RESERVE] {
+            let mut engine = SoundEngine::new(registry.clone());
+            engine.listener_reserve = reserve;
+            let mut backend = Null::default();
+            // Positional sounds take the static channels the reserve leaves; then their plays fail.
+            let started = (0..STATIC_CHANNELS)
+                .filter(|&i| {
+                    engine.play_new(block(i), false, &mut backend).1 == PlayResult::Started
+                })
+                .count();
+            assert_eq!(started, STATIC_CHANNELS - reserve);
+            let heard = engine.play_new(click(), false, &mut backend).1;
+            assert_eq!(
+                heard == PlayResult::Started,
+                reserve > 0,
+                "reserve {reserve}"
+            );
+        }
+    }
 }

crates/horizon-client-render/src/sprites.rs

@@ -349,10 +349,26 @@ impl Sprites {
         };
         self.register(root, name, decoded)
     }
+    /// The layer of a texture outside `textures/` (an OptiFine pack's connected-texture tile),
+    /// named by its resource path and added on first use. Unlike [`Sprites::insert`], a texture
+    /// that does not load is an error: the caller drops what needed it. Such files bypass the
+    /// disk cache, whose fingerprint covers only `textures/`.
+    pub fn insert_file(&mut self, root: &Path, resource: &str) -> Result<u32> {
+        if let Some(layer) = self.layers.get(resource) {
+            return Ok(*layer);
+        }
+        let decoded = Self::decode_file(&root.join(resource), resource)?;
+        self.register(root, resource, decoded)
+    }
     /// Read and decode one texture and its `.mcmeta`.
     fn decode(root: &Path, name: &str) -> Result<crate::sprite_cache::Decoded> {
         let (namespace, path) = name.split_once(':').ok_or("invalid sprite identifier")?;
-        let path = root.join(format!("assets/{namespace}/textures/{path}.png"));
+        Self::decode_file(
+            &root.join(format!("assets/{namespace}/textures/{path}.png")),
+            name,
+        )
+    }
+    fn decode_file(path: &Path, name: &str) -> Result<crate::sprite_cache::Decoded> {
         let metadata = match fs::read_to_string(path.with_extension("png.mcmeta")) {
             Ok(text) => Some(serde_json::from_str::<
                 BTreeMap<String, Box<serde_json::value::RawValue>>,
@@ -368,7 +384,7 @@ impl Sprites {
             .as_deref()
             .map(AnimationMetadata::from_json)
             .transpose()?;
-        let (png_width, png_height, pixels) = read_rgba(&path)?;
+        let (png_width, png_height, pixels) = read_rgba(path)?;
         let (width, height) = if let Some(animation) = &animation {
             let [width, height] =
                 animation.frame_size(i32::try_from(png_width)?, i32::try_from(png_height)?);
@@ -662,6 +678,33 @@ mod tests {
         }
     }
     #[test]
+    fn files_outside_textures_load_by_path() {
+        let root = std::env::temp_dir().join(format!("horizon-sprite-file-{}", std::process::id()));
+        let tile = "assets/minecraft/optifine/ctm/glass/0.png";
+        fs::create_dir_all(root.join(tile).parent().unwrap()).unwrap();
+        let mut encoder = png::Encoder::new(File::create(root.join(tile)).unwrap(), 16, 16);
+        encoder.set_color(png::ColorType::Rgba);
+        encoder.set_depth(png::BitDepth::Eight);
+        let pixels: Vec<u8> = (0..256).flat_map(|i| [i as u8, 0, 0, 128]).collect();
+        encoder
+            .write_header()
+            .unwrap()
+            .write_image_data(&pixels)
+            .unwrap();
+        let mut sprites = Sprites::default();
+        let layer = sprites.insert_file(&root, tile).unwrap();
+        assert_eq!(sprites.insert_file(&root, tile).unwrap(), layer);
+        assert!(sprites.translucent[layer as usize]);
+        // A missing tile is an error, not the missing texture.
+        assert!(
+            sprites
+                .insert_file(&root, "assets/minecraft/optifine/ctm/glass/1.png")
+                .is_err()
+        );
+        assert_eq!(sprites.count(), 1);
+        fs::remove_dir_all(&root).unwrap();
+    }
+    #[test]
     fn identical_still_textures_share_a_layer() {
         let root =
             std::env::temp_dir().join(format!("horizon-sprite-share-{}", std::process::id()));

crates/horizon-client-render/src/streaming.rs

@@ -6,6 +6,7 @@ use crate::fast_hash::{FxHashMap, FxHashSet};
 use crate::section_mask::SectionMask;
 use crate::{
     chunk::Chunk,
+    graphics::LeafCullingMode,
     light::{LightChanges, LightTables, apply_lighting, apply_relighting, light_chunk},
     mesher::{MeshScratch, MeshTables, Mesher, Region, SectionMesh, borrow},
     world::World,
@@ -149,6 +150,8 @@ pub trait LodSampler: Send {
     fn reduced_column(&mut self, x: i32, z: i32, _width: i32) -> crate::lod::Column {
         self.column(x, z)
     }
+    /// `side` x `side` columns from (`x`, `z`), `stride` blocks apart; none
+    /// when sampling failed and should be tried again later.
     fn grid(&mut self, x: i32, z: i32, stride: i32, side: usize) -> Vec<crate::lod::Column> {
         let mut columns = Vec::with_capacity(side * side);
         for dz in 0..side {
@@ -202,6 +205,7 @@ struct MeshSettings {
     blend_radius: i32,
     smooth_lighting: bool,
     cutout_leaves: bool,
+    leaf_culling: LeafCullingMode,
 }
 enum Job {
     Generate(i32, i32),
@@ -436,6 +440,8 @@ pub struct Streaming {
     /// The `ao` and `cutoutLeaves` options.
     pub smooth_lighting: bool,
     pub cutout_leaves: bool,
+    /// What the mesher does with leaf faces inside a canopy (`LeafCullingMode`).
+    pub leaf_culling: LeafCullingMode,
     /// Incremental relighting of block edits on lit chunks (see `light::relight`).
     light_tables: Arc<LightTables>,
     /// Applied edits by sequence, replayed onto light jobs snapshotted before them.
@@ -770,6 +776,7 @@ impl Streaming {
                                         blend_radius: settings.blend_radius,
                                         smooth_lighting: settings.smooth_lighting,
                                         cutout_leaves: settings.cutout_leaves,
+                                        leaf_culling: settings.leaf_culling,
                                         assets: &context.assets,
                                         render: &context.render,
                                         tables: &context.tables,
@@ -851,6 +858,7 @@ impl Streaming {
             biome_blend: 2,
             smooth_lighting: true,
             cutout_leaves: true,
+            leaf_culling: LeafCullingMode::Off,
             light_tables,
             light_log: Vec::new(),
             light_edit_sequence: 0,
@@ -1710,6 +1718,7 @@ impl Streaming {
                             blend_radius: self.biome_blend,
                             smooth_lighting: self.smooth_lighting,
                             cutout_leaves: self.cutout_leaves,
+                            leaf_culling: self.leaf_culling,
                         },
                     ),
                 );
@@ -2371,6 +2380,7 @@ mod tests {
         mesh.solid.resize(64, bytemuck::Zeroable::zeroed());
         mesh.translucent.resize(16, bytemuck::Zeroable::zeroed());
         mesh.block_entities.push(([1, 2, 3], 7));
+        mesh.lights.push(([1, 2, 3], 7));
         mesh.visibility = 0;
         mesh.sides = crate::mesher::Sides::unsorted(16);
         let capacities = mesh.capacity_bytes();
@@ -2387,6 +2397,7 @@ mod tests {
         assert!(reused.solid.is_empty());
         assert!(reused.translucent.is_empty());
         assert!(reused.block_entities.is_empty());
+        assert!(reused.lights.is_empty());
         assert_eq!(reused.visibility, crate::mesher::ALL_VISIBLE);
         assert_eq!(reused.sides, crate::mesher::Sides::default());
         assert_eq!(pool.bytes, 0);

crates/horizon-client-render/src/terrain.wgsl

@@ -92,19 +92,29 @@ fn sprite_level(uv: vec2<f32>, layer: u32, lod: f32) -> vec4<f32> {
 }
 // texture_sampling.glsl's sampleNearest: the sprite's texels stay square pixels, blending only
 // across the one screen pixel where two meet, so a linear (and anisotropic) sampler keeps them crisp.
+// `tiled`: a distant tile's face takes its sprite again per block, so its gradients span many
+// sprites while `uv` stays inside one (see `tile_uv` below).
 fn sample_nearest(uv: vec2<f32>, layer: u32, pixel: vec2<f32>, du: vec2<f32>, dv: vec2<f32>,
-                  texel_screen: vec2<f32>) -> vec4<f32> {
+                  texel_screen: vec2<f32>, tiled: bool) -> vec4<f32> {
     let texel_coords = uv / pixel;
     let center = round(texel_coords) - 0.5;
     var offset = texel_coords - center;
     offset = (offset - 0.5) * pixel / max(texel_screen, vec2(1e-12)) + 0.5;
     offset = clamp(offset, vec2(0.0), vec2(1.0));
-    return sprite_grad((center + offset) * pixel, layer, du, dv);
+    let at = (center + offset) * pixel;
+    if tiled {
+        // An anisotropic sampler lays its taps along those gradients, past the sprite's edge,
+        // where the clamped sampler reads that edge texel again: long streaks on the far tiles.
+        // Asking for the level the gradients give takes the one tap an anisotropy of 1 would.
+        let level = max(length(du), length(dv)) / min(pixel.x, pixel.y);
+        return sprite_level(at, layer, max(0.0, log2(level)));
+    }
+    return sprite_grad(at, layer, du, dv);
 }
 // sampleRGSS: four rotated-grid samples of the two nearest mip levels, faded in as the texels
 // shrink below two screen pixels, over sample_nearest.
 fn sample_rgss(uv: vec2<f32>, layer: u32, pixel: vec2<f32>, du: vec2<f32>, dv: vec2<f32>,
-               texel_screen: vec2<f32>) -> vec4<f32> {
+               texel_screen: vec2<f32>, tiled: bool) -> vec4<f32> {
     let max_texel = max(texel_screen.x, texel_screen.y);
     let min_pixel = min(pixel.x, pixel.y);
     let blend = smoothstep(min_pixel, min_pixel * 2.0, max_texel);
@@ -124,7 +134,7 @@ fn sample_rgss(uv: vec2<f32>, layer: u32, pixel: vec2<f32>, du: vec2<f32>, dv: v
         sum_high += sprite_level(p, layer, low + 1.0);
     }
     let rgss = mix(sum_low * 0.25, sum_high * 0.25, mip_blend);
-    return mix(sample_nearest(uv, layer, pixel, du, dv, texel_screen), rgss, blend);
+    return mix(sample_nearest(uv, layer, pixel, du, dv, texel_screen, tiled), rgss, blend);
 }
 // Distant terrain tiles (lod/mesh.rs) count their UVs in blocks past 1: each block takes the
 // sprite again, as separate faces would under the clamped sampler. Sprite UVs in [0, 1] stay.
@@ -137,12 +147,15 @@ fn sprite(tiled: vec2<f32>, layer: u32) -> vec4<f32> {
     let du = dpdx(tiled);
     let dv = dpdy(tiled);
     let uv = tile_uv(tiled);
+    // The wrap shifts a face's UVs by whole blocks, so half of one tells a tile's face from a
+    // block's (whose UVs stay inside its sprite).
+    let tiled_face = any(tiled - uv >= vec2(0.5));
     let pixel = vec2(1.0 / globals.filtering.y);
     let texel_screen = sqrt(du * du + dv * dv);
     if u32(globals.filtering.x) == 1u {
-        return sample_rgss(uv, layer, pixel, du, dv, texel_screen);
+        return sample_rgss(uv, layer, pixel, du, dv, texel_screen, tiled_face);
     }
-    return sample_nearest(uv, layer, pixel, du, dv, texel_screen);
+    return sample_nearest(uv, layer, pixel, du, dv, texel_screen, tiled_face);
 }
 
 struct TerrainOut {
@@ -295,6 +308,56 @@ fn fade_code(w: f32) -> u32 {
     return terrain_vertex(position, terrain_uv(uv, origin.w), layer, color, light, origin.xyz,
         origin.w);
 }
+// Solid terrain draws in two passes from the same draws: first the quads with no
+// cutout that are not fading, through `fs_opaque`, which never discards, so a tiled
+// GPU (Apple's) keeps hiding the pixels behind them; then the rest through
+// `fs_solid`. One discard anywhere in a pipeline's shader turned that hiding off for
+// all the terrain it drew. A quad the pass leaves out is decided before any of the
+// vertex's work and lies outside the clip volume: it makes no pixel.
+fn opaque_quad(layer: u32, w: f32) -> bool {
+    return (layer & 0x8000u) != 0u && fade_code(w) == 0u;
+}
+fn left_out() -> TerrainOut {
+    var out: TerrainOut;
+    out.clip = vec4(2.0, 2.0, 2.0, 1.0);
+    return out;
+}
+@vertex fn vs_terrain_opaque(
+    @location(0) position: vec3<f32>, @location(1) uv: vec2<u32>,
+    @location(2) layer: u32, @location(3) color: vec4<f32>, @location(4) light: vec2<u32>,
+    @location(5) origin: vec4<f32>) -> TerrainOut {
+    if !opaque_quad(layer, origin.w) { return left_out(); }
+    return terrain_vertex(position, terrain_uv(uv, origin.w), layer, color, light, origin.xyz,
+        origin.w);
+}
+@vertex fn vs_terrain_cutout(
+    @location(0) position: vec3<f32>, @location(1) uv: vec2<u32>,
+    @location(2) layer: u32, @location(3) color: vec4<f32>, @location(4) light: vec2<u32>,
+    @location(5) origin: vec4<f32>) -> TerrainOut {
+    if opaque_quad(layer, origin.w) { return left_out(); }
+    return terrain_vertex(position, terrain_uv(uv, origin.w), layer, color, light, origin.xyz,
+        origin.w);
+}
+@vertex fn vs_terrain_flat_opaque(
+    @builtin(vertex_index) vertex: u32,
+    @location(0) position: vec3<f32>, @location(1) uv: vec2<u32>,
+    @location(2) layer: u32, @location(3) color: vec4<f32>, @location(4) light: vec2<u32>
+) -> TerrainOut {
+    let origin = slot_origins[block_slots[vertex >> 8u]];
+    if !opaque_quad(layer, origin.w) { return left_out(); }
+    return terrain_vertex(position, terrain_uv(uv, origin.w), layer, color, light, origin.xyz,
+        origin.w);
+}
+@vertex fn vs_terrain_flat_cutout(
+    @builtin(vertex_index) vertex: u32,
+    @location(0) position: vec3<f32>, @location(1) uv: vec2<u32>,
+    @location(2) layer: u32, @location(3) color: vec4<f32>, @location(4) light: vec2<u32>
+) -> TerrainOut {
+    let origin = slot_origins[block_slots[vertex >> 8u]];
+    if opaque_quad(layer, origin.w) { return left_out(); }
+    return terrain_vertex(position, terrain_uv(uv, origin.w), layer, color, light, origin.xyz,
+        origin.w);
+}
 fn terrain_vertex(position: vec3<f32>, uv: vec2<f32>, layer: u32, color: vec4<f32>,
     light: vec2<u32>, origin: vec3<f32>, w: f32) -> TerrainOut {
     let pos = position + origin;
@@ -344,6 +407,13 @@ fn brightness(c: vec3<f32>) -> f32 {
 @fragment fn fs_solid(in: TerrainOut) -> @location(0) vec4<f32> {
     return solid_color(in);
 }
+// `fs_solid` for the opaque pass (`opaque_quad`): no fade, no cutout, no discard.
+@fragment fn fs_opaque(in: TerrainOut) -> @location(0) vec4<f32> {
+    let texel = sprite(in.uv, in.layer & 0x7fffu);
+    var color = texel * in.color;
+    color = mix(globals.fog_color * vec4(1.0, 1.0, 1.0, color.a), color, in.visibility);
+    return solid_finish(in, texel, color);
+}
 // The water mirror (gfx.rs's reflection pass): what lies below the water plane
 // (`fog_ends.w`, camera-relative) would show above it in the mirror, so it is cut away.
 @fragment fn fs_solid_mirror(in: TerrainOut) -> @location(0) vec4<f32> {
@@ -360,6 +430,10 @@ fn solid_color(in: TerrainOut) -> vec4<f32> {
     // terrain.fsh: the fade-in mixes toward the fog colour.
     color = mix(globals.fog_color * vec4(1.0, 1.0, 1.0, color.a), color, in.visibility);
     if color.a < 0.5 && (in.layer & 0x8000u) == 0u { discard; }
+    return solid_finish(in, texel, color);
+}
+// The rest of a solid pixel's colour once it is kept: emission and fog.
+fn solid_finish(in: TerrainOut, texel: vec4<f32>, color: vec4<f32>) -> vec4<f32> {
     // Below 0.75, alpha tells HDR output (hdr.wgsl) a light source's pixel may
     // shine, and at which tier (mesher::hdr_tier): 0.525 at the lowest, 0 at the
     // brightest. Only pixels as bright as their sprite's threshold may: its
@@ -517,6 +591,11 @@ fn sky_along_ray(d: vec3<f32>) -> vec3<f32> {
 @fragment fn fs_sky(in: SkyOut) -> @location(0) vec4<f32> {
     return vec4(sky_along_ray(view_ray(in.ndc)), 1.0);
 }
+// The first-person hand's depth clear inside the world pass: `vs_sky`'s triangle lies at the
+// far plane, written over the whole depth target with no colour.
+@fragment fn fs_depth_reset(in: SkyOut) -> @location(0) vec4<f32> {
+    return vec4(0.0);
+}
 @fragment fn fs_dark_disc(in: SkyOut) -> @location(0) vec4<f32> {
     let d = view_ray(in.ndc);
     let dist = disc_distance(d, -4.0);

crates/horizon-client/Cargo.toml

@@ -36,6 +36,7 @@ horizon-narrator = { path = "../horizon-narrator" }
 # Horizon mods: sandboxed WebAssembly components, off unless installed and turned on (docs/mods.md).
 # Their runtime is the `mods` feature.
 horizon-mods = { path = "../horizon-mods", default-features = false, features = ["index"] }
+horizon-optifine = { path = "../horizon-optifine" }
 wgpu = { version = "30.0.1", default-features = false, features = ["std", "parking_lot", "vulkan", "metal", "wgsl", "naga-ir"] }
 winit = "0.30.13"
 pollster = "0.4"

crates/horizon-client/assets/horizon/lang/en_us.json

@@ -34,6 +34,8 @@
   "horizon.pages.extras": "Horizon Extras",
   "horizon.pages.settings": "Horizon Settings",
   "horizon.pages.agent": "AI Agent",
+  "horizon.pages.split_settings": "Splitscreen Settings",
+  "horizon.pages.split_setup": "Splitscreen",
   "horizon.pages.split_profiles": "Who's playing?",
   "horizon.pages.settings.tooltip": "Horizon's own settings: graphics, controllers, extras and mods.",
   "horizon.pages.graphics.tooltip": "Graphics, simply: each setting says what it costs.",
@@ -41,6 +43,7 @@
   "horizon.pages.controller.tooltip": "Controllers: their buttons, sticks, vibration and menu navigation.",
   "horizon.pages.extras.tooltip": "Optional additions, all off by default: the game stays vanilla until you turn one on.",
   "horizon.pages.agent.tooltip": "Let your own AI agent play: horizon-ctl and MCP clients on this computer.",
+  "horizon.pages.split_setup.tooltip": "Players on this computer: controllers can join your world.",
   "horizon.pages.split_profiles.tooltip": "Who plays: a profile kept in this game folder.",
   "horizon.pages.shader_packs.tooltip": "Shader packs from the shaderpacks folder: Horizon's own and those in the shaders/ format. One runs at a time.",
   "horizon.pages.mods.tooltip": "Mods made for Horizon, from the horizon-mods folder. Each runs in a sandbox and stays off until you turn it on.",
@@ -48,6 +51,7 @@
   "horizon.pages.open.graphics_advanced": "Advanced Graphics...",
   "horizon.pages.open.shader_packs": "Shader Packs...",
   "horizon.pages.open.controller": "Controller Settings...",
+  "horizon.pages.open.split_setup": "Splitscreen...",
   "horizon.pages.open.extras": "Extras...",
   "horizon.pages.open.mods": "Mods...",
   "horizon.pages.open.agent": "AI Agent...",

crates/horizon-client/assets/horizon/lang/es_es.json

@@ -203,5 +203,11 @@
   "horizon.multiplayer.not_signed_in": "Este servidor está en modo en línea. Inicia sesión con tu cuenta de Microsoft en el launcher de Horizon para unirte.",
   "horizon.multiplayer.invalid_address": "Dirección de servidor no válida: %s",
   "horizon.multiplayer.connected_friend_direct": "Conectado directamente con tu amigo…",
-  "horizon.multiplayer.connected_friend_relay": "Conectado con tu amigo a través del relé…"
+  "horizon.multiplayer.connected_friend_relay": "Conectado con tu amigo a través del relé…",
+  "horizon.pages.shader_options": "Opciones de sombreadores",
+  "horizon.pages.split_profiles": "¿Quién juega?",
+  "horizon.pages.split_profiles.tooltip": "Quién juega: un perfil guardado en esta carpeta del juego.",
+  "horizon.shader_options.open": "Opciones de sombreadores…",
+  "horizon.shader_options.profile": "Perfil",
+  "horizon.shader_options.loading": "Leyendo las opciones del paquete de sombreadores…"
 }

crates/horizon-client/assets/horizon/lang/pl_pl.json

@@ -18,5 +18,11 @@
   "horizon.multiplayer.not_signed_in": "Ten serwer działa w trybie online. Zaloguj się kontem Microsoft w launcherze Horizon, aby dołączyć.",
   "horizon.multiplayer.invalid_address": "Nieprawidłowy adres serwera: %s",
   "horizon.multiplayer.connected_friend_direct": "Połączono bezpośrednio ze znajomym…",
-  "horizon.multiplayer.connected_friend_relay": "Połączono ze znajomym przez przekaźnik…"
+  "horizon.multiplayer.connected_friend_relay": "Połączono ze znajomym przez przekaźnik…",
+  "horizon.pages.shader_options": "Ustawienia shaderów",
+  "horizon.pages.split_profiles": "Kto gra?",
+  "horizon.pages.split_profiles.tooltip": "Kto gra: profil przechowywany w tym folderze gry.",
+  "horizon.shader_options.open": "Ustawienia shaderów…",
+  "horizon.shader_options.profile": "Profil",
+  "horizon.shader_options.loading": "Wczytywanie ustawień paczki shaderów…"
 }

crates/horizon-client/assets/horizon/lang/ru_ru.json

@@ -202,5 +202,11 @@
   "horizon.multiplayer.not_signed_in": "Этот сервер работает в онлайн-режиме. Войдите с помощью аккаунта Microsoft в лаунчере Horizon, чтобы присоединиться.",
   "horizon.multiplayer.invalid_address": "Недействительный адрес сервера: %s",
   "horizon.multiplayer.connected_friend_direct": "Установлено прямое соединение с другом…",
-  "horizon.multiplayer.connected_friend_relay": "Соединение с другом через релей…"
+  "horizon.multiplayer.connected_friend_relay": "Соединение с другом через релей…",
+  "horizon.pages.shader_options": "Настройки шейдеров",
+  "horizon.pages.split_profiles": "Кто играет?",
+  "horizon.pages.split_profiles.tooltip": "Кто играет: профиль, хранимый в этой папке игры.",
+  "horizon.shader_options.open": "Настройки шейдеров…",
+  "horizon.shader_options.profile": "Профиль",
+  "horizon.shader_options.loading": "Чтение настроек набора шейдеров…"
 }

crates/horizon-client/assets/horizon/lang/tr_tr.json

@@ -196,5 +196,11 @@
   "Threads that generate, light and mesh chunks. Next start.": "Parçaları oluşturan, aydınlatan ve ağ verilerini hazırlayan iş parçacıklarının sayısı. Değişiklikler sonraki başlatmada uygulanır.",
   "Vulkan, then DirectX 12 (Windows) or OpenGL (Linux) where it fails. Next start.": "Önce Vulkan kullanılır. Çalışmazsa Windows'ta DirectX 12, Linux'ta OpenGL denenir. Değişiklikler sonraki başlatmada uygulanır.",
   "Mesh data sent to the GPU per frame. Lower is smoother while loading.": "Her karede GPU'ya gönderilen ağ verisi miktarı. Daha düşük değerler yükleme sırasında daha akıcı bir deneyim sağlar.",
-  "Frame rate and frame times over the game, with a graph.": "Oyun ekranında FPS değerini ve kare sürelerini grafikle birlikte gösterir."
+  "Frame rate and frame times over the game, with a graph.": "Oyun ekranında FPS değerini ve kare sürelerini grafikle birlikte gösterir.",
+  "horizon.pages.shader_options": "Gölgelendirici Seçenekleri",
+  "horizon.pages.split_profiles": "Kim oynuyor?",
+  "horizon.pages.split_profiles.tooltip": "Kim oynuyor: bu oyun klasöründe tutulan bir profil.",
+  "horizon.shader_options.open": "Gölgelendirici Seçenekleri…",
+  "horizon.shader_options.profile": "Profil",
+  "horizon.shader_options.loading": "Gölgelendirici paketinin seçenekleri okunuyor…"
 }

crates/horizon-client/assets/horizon/lang/uk_ua.json

@@ -18,5 +18,11 @@
   "horizon.multiplayer.not_signed_in": "Цей сервер працює в онлайн-режимі. Увійдіть за допомогою акаунта Microsoft у лаунчері Horizon, щоб приєднатися.",
   "horizon.multiplayer.invalid_address": "Недійсна адреса сервера: %s",
   "horizon.multiplayer.connected_friend_direct": "Пряме з'єднання з другом встановлено…",
-  "horizon.multiplayer.connected_friend_relay": "З'єднання з другом через ретранслятор…"
+  "horizon.multiplayer.connected_friend_relay": "З'єднання з другом через ретранслятор…",
+  "horizon.pages.shader_options": "Налаштування шейдерів",
+  "horizon.pages.split_profiles": "Хто грає?",
+  "horizon.pages.split_profiles.tooltip": "Хто грає: профіль, що зберігається в цій теці гри.",
+  "horizon.shader_options.open": "Налаштування шейдерів…",
+  "horizon.shader_options.profile": "Профіль",
+  "horizon.shader_options.loading": "Читання налаштувань набору шейдерів…"
 }

crates/horizon-client/assets/horizon/lang/zh_cn.json

@@ -203,5 +203,11 @@
   "horizon.multiplayer.not_signed_in": "该服务器为在线模式服务器。请先在 Horizon 启动器中登录 Microsoft 账户再加入。",
   "horizon.multiplayer.invalid_address": "无效的服务器地址：%s",
   "horizon.multiplayer.connected_friend_direct": "已直连好友的世界…",
-  "horizon.multiplayer.connected_friend_relay": "已通过中继连接好友的世界…"
+  "horizon.multiplayer.connected_friend_relay": "已通过中继连接好友的世界…",
+  "horizon.pages.shader_options": "光影选项",
+  "horizon.pages.split_profiles": "谁在玩？",
+  "horizon.pages.split_profiles.tooltip": "谁在玩：保存在此游戏文件夹中的一份档案。",
+  "horizon.shader_options.open": "光影选项…",
+  "horizon.shader_options.profile": "档案",
+  "horizon.shader_options.loading": "正在读取光影包的选项…"
 }

crates/horizon-client/examples/chunk_load_bench.rs

@@ -17,6 +17,7 @@ use horizon_client::{
     biome::Biomes,
     blocks::BlockFacts,
     chunk::HEIGHT,
+    graphics::LeafCullingMode,
     light::LightTables,
     mesher::{MeshTables, Mesher, Region, borrow},
     models,
@@ -139,6 +140,7 @@ fn main() -> Result<(), Error> {
             blend_radius: 2,
             smooth_lighting: true,
             cutout_leaves: true,
+            leaf_culling: LeafCullingMode::Off,
             assets: &context.assets,
             render: &context.render,
             tables: &context.tables,

crates/horizon-client/examples/mod_port_probe.rs

@@ -133,7 +133,7 @@ fn main() -> Result<()> {
                 .collect();
             let descriptor = BlockState {
                 name: name.clone(),
-                properties,
+                properties: properties.into(),
             };
             let Some(id) = registry.id(&descriptor) else {
                 states.insert(key.clone(), Value::Null);

crates/horizon-client/examples/probe/hud_fixture/kinds.rs

@@ -328,5 +328,5 @@ fn chat(c: &Value, h: i32, atlas: &HudAtlas) -> Vec<GuiDraw> {
     if let Some(n) = c["scroll"].as_i64() {
         chat.scroll_by(n as i32, focused);
     }
-    chat.layout(h, c["now"].as_u64().unwrap_or(0), focused)
+    chat.layout(h, c["now"].as_f64().unwrap_or(0.0) as f32, focused)
 }

crates/horizon-client/examples/probe/mob_ai_probe.rs

@@ -179,7 +179,7 @@ fn state(registry: &BlockRegistry, text: &str) -> BlockStateId {
     registry
         .resolve(&BlockState {
             name: name.to_owned(),
-            properties,
+            properties: properties.into(),
         })
         .unwrap_or_else(|e| panic!("{text}: {e}"))
 }
@@ -1182,6 +1182,7 @@ pub fn main() -> horizon_client::Result<()> {
                     thundering: s.thunder,
                     nether: false,
                     block_tags: &items.block_tags,
+                    landing: &motion.landing,
                     biomes: &biomes,
                     mob_griefing: true,
                     universal_anger: false,

crates/horizon-client/examples/probe/section_mesh_fixture.rs

@@ -7,6 +7,7 @@ use horizon_client::{
     biome::{BiomeInfo, Biomes, GrassModifier},
     blocks::BlockFacts,
     chunk::{Chunk, Light, MIN_Y, index},
+    graphics::LeafCullingMode,
     mesher::{EMISSION_BITS, FLUID_FACE_BITS, MeshTables, Mesher, OPAQUE_LAYER, TerrainVertex},
     models,
 };
@@ -137,6 +138,7 @@ fn scene(
         blend_radius,
         smooth_lighting,
         cutout_leaves,
+        leaf_culling: LeafCullingMode::Off,
     };
     let section_y = int(&row["section_y"])?;
     let started = Instant::now();

crates/horizon-client/examples/probe/spawn_rules_fixture.rs

@@ -119,7 +119,7 @@ fn parse_state(spec: &str) -> BlockState {
         .collect();
     BlockState {
         name: name.to_owned(),
-        properties,
+        properties: properties.into(),
     }
 }
 

crates/horizon-client/src/advancements.rs

@@ -2,6 +2,7 @@
 //! progress (`PlayerAdvancements`) and the predicates criteria test
 //! (`EntityPredicate`, `ItemPredicate`, `LocationPredicate`, the loot
 //! conditions advancements use).
+use horizon_world::lazy_json::LazyJson;
 use serde_json::Value;
 use std::{
     collections::{BTreeMap, BTreeSet, HashMap},
@@ -30,7 +31,9 @@ pub struct Display {
 pub struct Criterion {
     pub name: String,
     pub trigger: String,
-    pub conditions: Value,
+    /// Read on first test: ~1,300 recipe advancements' criteria, most never
+    /// tested in a game, took ~4 MB as `Value`s.
+    pub conditions: LazyJson,
 }
 #[derive(Clone, Debug, Default)]
 pub struct Rewards {
@@ -154,7 +157,8 @@ impl Tree {
             .into_iter()
             .flatten()
         {
-            match self.list[ai].criteria[ci].conditions["recipes"].as_str() {
+            // `read`: the index alone keeps none of the criteria read.
+            match self.list[ai].criteria[ci].conditions.read()["recipes"].as_str() {
                 Some(r) => self
                     .by_recipe
                     .entry(r.to_owned())
@@ -208,7 +212,8 @@ impl InventoryIndex {
             return index;
         };
         for &(ai, ci) in list {
-            let items = &tree.list[ai].criteria[ci].conditions["items"];
+            let conditions = tree.list[ai].criteria[ci].conditions.read();
+            let items = &conditions["items"];
             // `id_matches`: only a string or a list limits the items.
             let limited = items.as_array().and_then(|a| {
                 a.iter()
@@ -266,7 +271,7 @@ fn parse(id: &str, v: &Value) -> Option<Advancement> {
         .map(|(name, c)| Criterion {
             name: name.clone(),
             trigger: c["trigger"].as_str().unwrap_or("").to_owned(),
-            conditions: c["conditions"].clone(),
+            conditions: LazyJson::new(&c["conditions"]),
         })
         .collect();
     let requirements = match v["requirements"].as_array() {
@@ -1606,7 +1611,7 @@ mod tests {
                 criteria: vec![Criterion {
                     name: "c".into(),
                     trigger: "minecraft:inventory_changed".into(),
-                    conditions,
+                    conditions: LazyJson::new(&conditions),
                 }],
                 requirements: vec![vec!["c".into()]],
                 rewards: Rewards::default(),
@@ -1655,7 +1660,7 @@ mod tests {
                 criteria: vec![Criterion {
                     name: "c".into(),
                     trigger: "minecraft:recipe_unlocked".into(),
-                    conditions,
+                    conditions: LazyJson::new(&conditions),
                 }],
                 requirements: vec![vec!["c".into()]],
                 rewards: Rewards::default(),

crates/horizon-client/src/arrows.rs

@@ -478,7 +478,7 @@ pub fn blocks_inside(from: Vec3, to: Vec3) -> Vec<BlockPos> {
     inside
 }
 /// `Projectile.lerpRotation`.
-fn lerp_rotation(mut old: f32, new: f32) -> f32 {
+pub fn lerp_rotation(mut old: f32, new: f32) -> f32 {
     while new - old < -180.0 {
         old -= 360.0;
     }

crates/horizon-client/src/bin/horizon-ctl/commands.rs

@@ -445,6 +445,7 @@ pub const COMMANDS: &[Cmd] = &[
         ["horizon-ctl mcp"], &[], mcp: false, local: true),
     cmd!("bench", Scripting, "bench SECONDS", "reset frame stats, wait, reply with the summary", "", ["horizon-ctl bench 10"], &[p("seconds", Ty::Num, "how long to measure")], mcp: true, local: false),
     cmd!("stats", Scripting, "stats [reset]", "frame-time summary since the last reset", "", ["horizon-ctl stats"], &[opt("reset", Ty::Bool, "start counting again")], mcp: true, local: false),
+    cmd!("gpu-passes", Scripting, "gpu-passes [on|off]", "time Horizon's own render passes on the GPU, shown in F3 and in stats and bench", "", ["horizon-ctl gpu-passes on"], &[opt("mode", Ty::Enum(&["on", "off"]), "on or off; without it, only reports")], mcp: false, local: false),
     cmd!("fly", Scripting, "fly X1 Y1 Z1 X2 Y2 Z2 SECONDS [PITCH [raw]]", "fly the camera along a line, then reply with the frame summary",
         "The reply's tick_ms and tick_ms_max are the world's smoothed tick time over the flight (the server thread's when single player runs on one). With raw, the reply also lists every frame time in milliseconds (frame_ms).",
         ["horizon-ctl fly 0 100 0 500 100 0 20"], &[], mcp: false, local: false),

crates/horizon-client/src/bin/horizon-ctl/mcp.rs

@@ -6,7 +6,19 @@ use crate::{Session, commands};
 use serde_json::{Value, json};
 use std::io::{BufRead, Write};
 
-const PROTOCOL: &str = "2025-06-18";
+/// Revisions this server implements. Older ones are not claimed: only the revision actually
+/// implemented is advertised (no JSON-RPC batches, no other capability than `tools`).
+const SUPPORTED: &[&str] = &["2025-06-18"];
+
+/// MCP lifecycle: answer with the client's version if supported, otherwise one we support.
+fn negotiate_version(params: &Value) -> &'static str {
+    let wanted = params.get("protocolVersion").and_then(Value::as_str);
+    SUPPORTED
+        .iter()
+        .copied()
+        .find(|v| Some(*v) == wanted)
+        .unwrap_or(SUPPORTED[0])
+}
 
 fn tools() -> Vec<Value> {
     commands::COMMANDS
@@ -134,7 +146,7 @@ impl Session {
     fn handle(&mut self, method: &str, params: &Value) -> Result<Value, (i64, String)> {
         match method {
             "initialize" => Ok(json!({
-                "protocolVersion": params.get("protocolVersion").and_then(Value::as_str).unwrap_or(PROTOCOL),
+                "protocolVersion": negotiate_version(params),
                 "capabilities": { "tools": {} },
                 "serverInfo": { "name": "horizon-ctl", "version": horizon_core::release::VERSION },
                 "instructions": "Play Horizon, a Rust reimplementation of Minecraft Java Edition. Start with launch (it finds the game installed by the Horizon launcher and opens or creates a world), then read the world with state, inventory, screen, entities and find_block, and act with goto, look_at_block, break, place, interact, click_slot and click_button. Actions block until they finish and report what happened. Coordinates are block coordinates; yaw 0 faces south (+Z).",
@@ -194,7 +206,17 @@ pub fn serve(session: &mut Session) -> Result<(), String> {
 
 #[cfg(test)]
 mod tests {
+
     use super::*;
+    #[test]
+    fn version_negotiation() {
+        let v = |p: Value| negotiate_version(&p);
+        assert_eq!(v(json!({ "protocolVersion": "2025-06-18" })), "2025-06-18");
+        assert_eq!(v(json!({ "protocolVersion": "2026-07-28" })), "2025-06-18");
+        assert_eq!(v(json!({ "protocolVersion": "1999-01-01" })), "2025-06-18");
+        assert_eq!(v(json!({ "protocolVersion": 7 })), "2025-06-18");
+        assert_eq!(v(json!({})), "2025-06-18");
+    }
 
     #[test]
     fn base64_matches_rfc_4648() {
@@ -234,9 +256,9 @@ mod tests {
     fn protocol_basics() {
         let mut s = Session::new(std::env::temp_dir().join("horizon-ctl-mcp-test.sock"), None);
         let init = s
-            .handle("initialize", &json!({ "protocolVersion": "2025-03-26" }))
+            .handle("initialize", &json!({ "protocolVersion": "2025-06-18" }))
             .unwrap();
-        assert_eq!(init["protocolVersion"], "2025-03-26");
+        assert_eq!(init["protocolVersion"], "2025-06-18");
         assert!(s.handle("nope", &json!({})).is_err());
         let r = s
             .handle(

crates/horizon-client/src/block_entity_item.rs

@@ -283,6 +283,25 @@ fn custom_only(saved: &Tag) -> Compound {
     }
 }
 
+/// `BlockEntity.collectComponents`: explicit components plus the type's implicit components.
+/// Unlike Ctrl + Pick Block, this does not carry the remaining block entity NBT.
+pub fn collected_components(saved: &Tag) -> Compound {
+    let id = block_entity_nbt::id(saved).unwrap_or_default();
+    let mut collected = match saved.get("components") {
+        Some(Tag::Compound(c)) => c.clone(),
+        _ => Compound::new(),
+    };
+    for part in parts(&id) {
+        if let Some((component, value)) = collect(*part, saved) {
+            match value {
+                Some(v) => collected.insert(component.into(), v),
+                None => collected.remove(&JavaString::from(component)),
+            };
+        }
+    }
+    collected
+}
+
 /// `addBlockDataToItem`: the component patch Ctrl + Pick Block gives the clone
 /// item of the block entity saved as `saved` (a full, canonical compound).
 pub fn pick(saved: &Tag) -> Compound {
@@ -310,19 +329,7 @@ pub fn pick(saved: &Tag) -> Compound {
     // ItemStack.applyComponents(collectComponents()): the block entity's own
     // components, then the implicit ones; a value equal to the item's own is
     // no change.
-    let mut collected = match saved.get("components") {
-        Some(Tag::Compound(c)) => c.clone(),
-        _ => Compound::new(),
-    };
-    for part in parts(&id) {
-        if let Some((component, value)) = collect(*part, saved) {
-            match value {
-                Some(v) => collected.insert(component.into(), v),
-                None => collected.remove(&JavaString::from(component)),
-            };
-        }
-    }
-    for (component, value) in collected {
+    for (component, value) in collected_components(saved) {
         if item_default(&component.to_string_lossy()).as_ref() == Some(&value) {
             patch.remove(&component);
         } else {

crates/horizon-client/src/crafting.rs

@@ -1219,6 +1219,15 @@ pub(crate) fn recipe_files(dir: &Path) -> Result<Vec<(String, PathBuf)>> {
     Ok(named)
 }
 /// The type of a recipe the game doesn't craft itself: one outside `minecraft`.
+/// A recipe's whole id from its name in the tables: vanilla's are kept bare
+/// (`oak_planks`), everyone else's whole (`mymod:crusher/iron`).
+pub fn recipe_id(name: &str) -> String {
+    if name.contains(':') {
+        name.to_owned()
+    } else {
+        format!("minecraft:{name}")
+    }
+}
 fn custom_type(v: &Value) -> Option<&str> {
     v["type"]
         .as_str()
@@ -1309,10 +1318,14 @@ fn matches_all(ingredients: &[Ingredient], stacks: &[&ItemStack]) -> bool {
 }
 impl Recipes {
     pub fn load(root: &Path, items: &Items, overlay: &PackOverlay) -> Result<Self> {
-        let mut crafting = Vec::new();
-        let mut cooking = Vec::new();
-        let mut custom: HashMap<String, Vec<CustomRecipe>> = HashMap::new();
-        let mut meta = HashMap::new();
+        let sources = Self::sources(root, overlay)?;
+        Self::from_sources(root, items, overlay, sources)
+    }
+    /// The recipe files the tables are built from, each id once: vanilla's by
+    /// bare name, then the content mods' as `<ns>:<name>`, the world's packs'
+    /// over them (`overlay`), parsed, and only those whose load conditions
+    /// hold. A server sends some of them to its clients (`recipe_content`).
+    pub fn sources(root: &Path, overlay: &PackOverlay) -> Result<Vec<(String, Value)>> {
         // Vanilla's recipes by bare name, then content mods' as `<ns>:<name>`.
         let mut sources: Vec<(String, Vec<u8>)> = Vec::new();
         // NeoForge's load conditions: `mod_loaded` asks which mods' data is
@@ -1356,10 +1369,12 @@ impl Recipes {
                 None => sources.push((name, bytes)),
             }
         }
+        let filters = horizon_items::recipe_filters::RecipeFilters::load(root, overlay);
+        let mut parsed = Vec::with_capacity(sources.len());
         for (name, bytes) in sources {
             // Vanilla's RecipeManager logs a file that does not parse and
             // goes on ("Couldn't parse data file").
-            let v: Value = match serde_json::from_slice(&bytes) {
+            let mut v: Value = match serde_json::from_slice(&bytes) {
                 Ok(v) => v,
                 Err(e) => {
                     log::warn!("Horizon: recipe {name} not loaded: {e}");
@@ -1373,6 +1388,27 @@ impl Recipes {
             }) {
                 continue;
             }
+            // The data's recipe filters, over the final set.
+            if !filters.apply(&recipe_id(&name), &mut v) {
+                continue;
+            }
+            parsed.push((name, v));
+        }
+        Ok(parsed)
+    }
+    /// The tables from `sources` (`Recipes::sources`' shape); `root` and
+    /// `overlay` give the enchantment tags the tables keep.
+    pub fn from_sources(
+        root: &Path,
+        items: &Items,
+        overlay: &PackOverlay,
+        sources: Vec<(String, Value)>,
+    ) -> Result<Self> {
+        let mut crafting = Vec::new();
+        let mut cooking = Vec::new();
+        let mut custom: HashMap<String, Vec<CustomRecipe>> = HashMap::new();
+        let mut meta = HashMap::new();
+        for (name, v) in sources {
             if let Some(kind) = custom_type(&v) {
                 let id = if name.contains(':') {
                     name
@@ -2163,6 +2199,44 @@ mod tests {
         assert!(ids.iter().any(|r| r.id == "minecraft:pack_yes"));
         let _ = fs::remove_dir_all(&root);
     }
+    /// A pack's recipe filter removes a recipe and swaps a mod recipe's input
+    /// in the loaded tables, after the packs are merged.
+    #[test]
+    fn recipe_filters_remove_and_swap() {
+        let root = std::env::temp_dir().join(format!("horizon-filters-{}", std::process::id()));
+        let _ = fs::remove_dir_all(&root);
+        fs::create_dir_all(root.join("data/minecraft/recipe")).unwrap();
+        let crusher = |input: &str| {
+            format!(
+                r#"{{"type":"mymod:crusher","input":"{input}","result":{{"id":"mymod:dust"}}}}"#
+            )
+            .into_bytes()
+        };
+        fs::write(
+            root.join("data/minecraft/recipe/iron.json"),
+            crusher("minecraft:iron_ingot"),
+        )
+        .unwrap();
+        fs::write(
+            root.join("data/minecraft/recipe/gold.json"),
+            crusher("minecraft:gold_ingot"),
+        )
+        .unwrap();
+        let filter = br##"{"filters":[
+            {"id":"minecraft:gold","remove":true},
+            {"type":"mymod:*","replace_input":{"from":"minecraft:iron_ingot","to":"#c:ingots/iron"}}
+        ]}"##;
+        let packs = [("recipe_filter/pack:f".to_owned(), vec![filter.to_vec()])];
+        let items = Items::for_tests(HashMap::new());
+        let recipes = Recipes::load(&root, &items, &PackOverlay { files: &packs }).unwrap();
+        let crushed = &recipes.custom["mymod:crusher"];
+        assert_eq!(
+            crushed.iter().map(|r| r.id.as_str()).collect::<Vec<_>>(),
+            ["minecraft:iron"]
+        );
+        assert_eq!(crushed[0].json["input"], "#c:ingots/iron");
+        let _ = fs::remove_dir_all(&root);
+    }
     #[test]
     fn cook_finds_the_first_recipe_the_scan_finds() {
         let recipes = cooking_book();

crates/horizon-client/src/debug_overlay.rs

@@ -86,15 +86,17 @@ impl Displayer {
 /// Horizon's own lines: the shader pack's GPU time, then its costliest passes (`passes`: each
 /// pass's median milliseconds, in the order they run).
 pub fn shader_pass_lines(passes: &[(String, f32)]) -> Vec<String> {
+    labelled_pass_lines("Shader pack GPU", passes)
+}
+
+/// `label` and the passes' total, then the costliest passes by GPU time.
+pub fn labelled_pass_lines(label: &str, passes: &[(String, f32)]) -> Vec<String> {
     const SHOWN: usize = 8;
     if passes.is_empty() {
         return Vec::new();
     }
     let total: f32 = passes.iter().map(|p| p.1).sum();
-    let mut lines = vec![format!(
-        "Shader pack GPU: {total:.2} ms in {} passes",
-        passes.len()
-    )];
+    let mut lines = vec![format!("{label}: {total:.2} ms in {} passes", passes.len())];
     let mut costliest: Vec<&(String, f32)> = passes.iter().collect();
     costliest.sort_by(|a, b| b.1.total_cmp(&a.1));
     lines.extend(

crates/horizon-client/src/entities.rs

@@ -201,6 +201,7 @@ impl ItemEntity {
         collision: &BlockCollisionRegistry<'_>,
         no_physics: bool,
         fluids: &crate::motion::FluidResources,
+        entity_boxes: &[Aabb],
     ) -> bool {
         self.ticks += 1;
         self.previous = self.position;
@@ -241,10 +242,20 @@ impl ItemEntity {
             // Entity.move with noPhysics: straight through, the ground as it was.
             let moved = if no_physics {
                 wanted
-            } else {
+            } else if entity_boxes.is_empty() {
                 scene
                     .resolve(self.bounds(), wanted, 0.0, self.on_ground)
                     .unwrap_or(Vec3::ZERO)
+            } else {
+                // `Entity.collide`: the entities that `canBeCollidedWith` the item stop it
+                // too (a boat, a minecart, a shulker, a happy ghast held still).
+                crate::collisions::EntityCollisions {
+                    blocks: scene,
+                    entities: entity_boxes,
+                    border: None,
+                }
+                .resolve(self.bounds(), wanted, 0.0, self.on_ground)
+                .unwrap_or(Vec3::ZERO)
             };
             self.position = Vec3::new(
                 self.position.x + moved.x,
@@ -405,6 +416,71 @@ impl ItemEntity {
         self.pickup_delay != u32::MAX && age < 6000 && self.stack.count < max_stack
     }
 }
+/// The boxes that stop a dropped item (boats, minecarts, shulkers, a held-still happy ghast),
+/// binned by 8-block cell, so an item looks only at the ones near it: a farm with many drops and
+/// many vehicles checks a handful of boxes per item, not every box in the level.
+#[derive(Default)]
+pub struct ObstacleGrid {
+    cells: crate::fast_hash::FxHashMap<(i32, i32, i32), Vec<u32>>,
+    boxes: Vec<Aabb>,
+}
+impl ObstacleGrid {
+    const CELL: f64 = 8.0;
+    pub fn new(boxes: Vec<Aabb>) -> Self {
+        let mut cells: crate::fast_hash::FxHashMap<(i32, i32, i32), Vec<u32>> = Default::default();
+        for (i, b) in boxes.iter().enumerate() {
+            let (lo, hi) = Self::span(*b);
+            for x in lo.0..=hi.0 {
+                for y in lo.1..=hi.1 {
+                    for z in lo.2..=hi.2 {
+                        cells.entry((x, y, z)).or_default().push(i as u32);
+                    }
+                }
+            }
+        }
+        Self { cells, boxes }
+    }
+    fn span(b: Aabb) -> ((i32, i32, i32), (i32, i32, i32)) {
+        let cell = |v: Vec3| {
+            (
+                (v.x / Self::CELL).floor() as i32,
+                (v.y / Self::CELL).floor() as i32,
+                (v.z / Self::CELL).floor() as i32,
+            )
+        };
+        (cell(b.min_position()), cell(b.max_position()))
+    }
+    pub fn is_empty(&self) -> bool {
+        self.boxes.is_empty()
+    }
+    /// The boxes meeting `area` (`getEntityCollisions`'s query box), in the order they were given.
+    pub fn near(&self, area: Aabb, out: &mut Vec<Aabb>) {
+        out.clear();
+        if self.boxes.is_empty() {
+            return;
+        }
+        let (lo, hi) = Self::span(area);
+        let mut found: Vec<u32> = Vec::new();
+        for x in lo.0..=hi.0 {
+            for y in lo.1..=hi.1 {
+                for z in lo.2..=hi.2 {
+                    if let Some(list) = self.cells.get(&(x, y, z)) {
+                        found.extend(list);
+                    }
+                }
+            }
+        }
+        found.sort_unstable();
+        found.dedup();
+        out.extend(
+            found
+                .into_iter()
+                .map(|i| self.boxes[i as usize])
+                .filter(|b| b.intersects(area)),
+        );
+    }
+}
+
 /// Dropped items by block cell, for `ItemEntity.mergeWithNeighbours`'s
 /// search around an item. Holds indexes into the tick's item list.
 #[derive(Default)]
@@ -1081,6 +1157,12 @@ pub struct ArmorStand {
     /// `ArmorStand.disabledSlots`: bit `filterFlag` locks a slot, bit
     /// `filterFlag + 8` takes from it and bit `filterFlag + 16` puts into it.
     pub disabled_slots: i32,
+    /// Server-only `LivingEntity.lastPos` for location-based enchantments.
+    pub enchantment_block: Option<BlockPos>,
+    /// Travel accumulated for `LivingEntity.checkFallDamage`'s landing callback.
+    pub enchantment_fall_distance: f64,
+    /// Last equipment seen by `collectEquipmentChanges`; not saved to NBT.
+    pub enchantment_equipment: [Option<ItemStack>; 6],
 }
 impl ArmorStand {
     pub const SLOTS: [&'static str; 6] = ["mainhand", "offhand", "feet", "legs", "chest", "head"];
@@ -1152,6 +1234,9 @@ impl ArmorStand {
             pose: Self::DEFAULT_POSE,
             vehicle: None,
             disabled_slots: 0,
+            enchantment_block: None,
+            enchantment_fall_distance: 0.0,
+            enchantment_equipment: Default::default(),
         }
     }
     /// `EquipmentSlot.getFilterFlag` of an `equipment` index (main hand, off
@@ -1721,7 +1806,15 @@ mod honey_slide_tests {
         item.id = 1;
         let mut ys = Vec::new();
         for _ in 0..8 {
-            item.tick(&world, assets.registry, &facts, &collision, false, &fluids);
+            item.tick(
+                &world,
+                assets.registry,
+                &facts,
+                &collision,
+                false,
+                &fluids,
+                &[],
+            );
             ys.push(item.velocity.y);
         }
         // Idle ticks keep gravity; the 4th tick's move hits the floor and
@@ -1777,7 +1870,15 @@ mod honey_slide_tests {
         item.id = 1;
         let before = item.position.y;
         for _ in 0..16 {
-            item.tick(&world, assets.registry, &facts, &collision, false, &fluids);
+            item.tick(
+                &world,
+                assets.registry,
+                &facts,
+                &collision,
+                false,
+                &fluids,
+                &[],
+            );
         }
         assert!(
             item.position.y > before + 0.5,
@@ -1787,7 +1888,7 @@ mod honey_slide_tests {
         );
     }
 
-    fn falling_item(x: f64, y: f64, z: f64, vx: f64, vy: f64, vz: f64) -> ItemEntity {
+    pub(super) fn falling_item(x: f64, y: f64, z: f64, vx: f64, vy: f64, vz: f64) -> ItemEntity {
         let at = Vec3::new(x, y, z);
         ItemEntity {
             id: 1,
@@ -1995,7 +2096,15 @@ mod slime_bounce_tests {
         falling.on_ground = false;
         falling.age = 0;
         falling.id = 1;
-        falling.tick(&world, assets.registry, &facts, &collision, false, &fluids);
+        falling.tick(
+            &world,
+            assets.registry,
+            &facts,
+            &collision,
+            false,
+            &fluids,
+            &[],
+        );
         assert_eq!(falling.position.y, 4.0);
         assert!(falling.velocity.y > 0.0);
         assert!(falling.on_ground);
@@ -2005,7 +2114,15 @@ mod slime_bounce_tests {
         // does not set needs_sync.
         falling.velocity = Vec3::ZERO;
         falling.needs_sync = false;
-        falling.tick(&world, assets.registry, &facts, &collision, false, &fluids);
+        falling.tick(
+            &world,
+            assets.registry,
+            &facts,
+            &collision,
+            false,
+            &fluids,
+            &[],
+        );
         assert!(!falling.needs_sync);
     }
 }
@@ -2060,3 +2177,117 @@ mod unstuck_tests {
         assert_eq!(ExperienceOrb::unstuck(at, &BORDER, shapes(&solid)), None);
     }
 }
+
+#[cfg(test)]
+mod entity_collision_tests {
+    use super::honey_slide_tests::falling_item;
+    use super::*;
+
+    /// `Entity.collide` stops an item at the entities that `canBeCollidedWith` it: dropped
+    /// above a boat's box (or a still happy ghast's) it lands on the box's top and rests,
+    /// where with no box it falls to the floor of the scene.
+    #[test]
+    fn an_item_lands_on_an_entity_box_under_it() {
+        let root = std::path::Path::new(env!("CARGO_MANIFEST_DIR"))
+            .join("../../.local/horizon-client")
+            .join(horizon_core::VANILLA_VERSION);
+        if !root.join("movement-properties.nbt").exists() {
+            return;
+        }
+        let assets = crate::assets::Assets::load(&root).unwrap();
+        let render = assets.reload(&root).unwrap();
+        let facts = crate::blocks::BlockFacts::load(&root, assets.registry).unwrap();
+        let fluids = crate::motion::FluidResources::new(&assets, &facts).unwrap();
+        let collision = crate::collisions::load(&root, assets.registry).unwrap();
+        let mut world = World::test_scene(&assets, &render, 3).unwrap();
+        let stone = assets.registry.default_state("minecraft:stone").unwrap();
+        world.set(20, 3, 20, stone).unwrap();
+        let rest = |boxes: &[Aabb]| {
+            let mut item = falling_item(20.5, 12.0, 20.5, 0.0, 0.0, 0.0);
+            item.id = 1;
+            for _ in 0..80 {
+                item.tick(
+                    &world,
+                    assets.registry,
+                    &facts,
+                    &collision,
+                    false,
+                    &fluids,
+                    boxes,
+                );
+            }
+            item.position.y
+        };
+        // The stone's top is at 4.0; a box from 5.0 to 9.0 is in the way.
+        let platform = Aabb::new(Vec3::new(19.0, 5.0, 19.0), Vec3::new(22.0, 9.0, 22.0));
+        assert!((rest(&[]) - 4.0).abs() < 1.0e-6, "on the stone with no box");
+        assert!(
+            (rest(&[platform]) - 9.0).abs() < 1.0e-6,
+            "on top of the box, at its top"
+        );
+    }
+
+    #[test]
+    fn obstacle_grid_returns_only_the_boxes_near_an_item() {
+        // A boat every 100 blocks along a line, 1000 of them.
+        let boat = |x: f64| {
+            Aabb::new(
+                Vec3::new(x, 64.0, 0.0),
+                Vec3::new(x + 1.375, 64.5625, 1.375),
+            )
+        };
+        let grid = ObstacleGrid::new((0..1000).map(|i| boat(f64::from(i) * 100.0)).collect());
+        let mut out = Vec::new();
+        // Around the 7th boat: only it.
+        let area = Aabb::new(Vec3::new(699.0, 63.0, -1.0), Vec3::new(701.0, 66.0, 1.0));
+        grid.near(area, &mut out);
+        assert_eq!(out, vec![boat(700.0)]);
+        // Between two boats: none.
+        let area = Aabb::new(Vec3::new(750.0, 63.0, 0.0), Vec3::new(751.0, 66.0, 1.0));
+        grid.near(area, &mut out);
+        assert!(out.is_empty());
+        // A box spanning cells is found from any of them, once.
+        let wide = Aabb::new(Vec3::new(0.0, 0.0, 0.0), Vec3::new(20.0, 1.0, 1.0));
+        let grid = ObstacleGrid::new(vec![wide]);
+        let area = Aabb::new(Vec3::new(17.0, 0.0, 0.0), Vec3::new(18.0, 1.0, 1.0));
+        grid.near(area, &mut out);
+        assert_eq!(out, vec![wide]);
+    }
+
+    /// A farm: 5000 drops and 1000 separated vehicles. Run with `-- --ignored --nocapture`.
+    #[test]
+    #[ignore = "timing"]
+    fn obstacle_grid_beats_scanning_every_box_for_a_big_farm() {
+        let boat = |i: u32| {
+            let (x, z) = (f64::from(i % 40) * 6.0, f64::from(i / 40) * 6.0);
+            Aabb::new(
+                Vec3::new(x, 64.0, z),
+                Vec3::new(x + 1.375, 64.5625, z + 1.375),
+            )
+        };
+        let boxes: Vec<Aabb> = (0..1000).map(boat).collect();
+        let items: Vec<Aabb> = (0..5000)
+            .map(|i| {
+                let (x, z) = (f64::from(i % 70) * 3.4, f64::from(i / 70) * 3.4);
+                Aabb::new(Vec3::new(x, 64.0, z), Vec3::new(x + 0.25, 64.25, z + 0.25))
+            })
+            .collect();
+        let start = std::time::Instant::now();
+        let mut hits = 0;
+        for item in &items {
+            let area = item.inflate(Vec3::new(1.0, 1.0, 1.0));
+            hits += boxes.iter().filter(|b| b.intersects(area)).count();
+        }
+        let scan = start.elapsed();
+        let grid = ObstacleGrid::new(boxes);
+        let start = std::time::Instant::now();
+        let (mut out, mut found) = (Vec::new(), 0);
+        for item in &items {
+            grid.near(item.inflate(Vec3::new(1.0, 1.0, 1.0)), &mut out);
+            found += out.len();
+        }
+        let binned = start.elapsed();
+        assert_eq!(hits, found);
+        println!("scan {scan:?}, grid {binned:?}");
+    }
+}

crates/horizon-client/src/entities/fluids.rs

@@ -246,17 +246,41 @@ mod tests {
             needs_sync: false,
         };
         let mut still = item.clone();
-        assert!(still.tick(&world, assets.registry, &facts, &collision, false, &fluids));
+        assert!(still.tick(
+            &world,
+            assets.registry,
+            &facts,
+            &collision,
+            false,
+            &fluids,
+            &[]
+        ));
         assert_eq!(still.position.x, at.x);
         assert_eq!(still.velocity.x, 0.0);
         world.set(21, 4, 20, flowing).unwrap();
         let mut carried = item;
-        assert!(carried.tick(&world, assets.registry, &facts, &collision, false, &fluids));
+        assert!(carried.tick(
+            &world,
+            assets.registry,
+            &facts,
+            &collision,
+            false,
+            &fluids,
+            &[]
+        ));
         // First push is damped by buoyancy before motion, second follows drag.
         assert!((carried.position.x - at.x - 0.014 * 0.99).abs() < 1e-12);
         assert!((carried.velocity.x - (0.014 * 0.99 * 0.98 + 0.014)).abs() < 1e-12);
         for _ in 0..20 {
-            carried.tick(&world, assets.registry, &facts, &collision, false, &fluids);
+            carried.tick(
+                &world,
+                assets.registry,
+                &facts,
+                &collision,
+                false,
+                &fluids,
+                &[],
+            );
         }
         assert!(carried.position.x > at.x + 0.5);
     }

crates/horizon-client/src/entity_culling.rs

@@ -40,23 +40,39 @@ impl Culler {
         start: usize,
         opaque: impl FnMut([i32; 3]) -> bool,
     ) -> bool {
-        if start >= vertices.len() || self.remaining.get() == 0 {
+        if self.remaining.get() == 0 {
             return false;
         }
+        let Some((min, max)) = Self::bounds(self.camera, vertices, start) else {
+            return false;
+        };
+        self.occluded(min, max, opaque)
+    }
+
+    /// Camera-relative bounds grown to include floating-point and rasterization
+    /// edges. The asynchronous path sends these small queries to its worker.
+    pub fn bounds(
+        camera: [f64; 3],
+        vertices: &[crate::mesher::Vertex],
+        start: usize,
+    ) -> Option<([f64; 3], [f64; 3])> {
+        if start >= vertices.len() {
+            return None;
+        }
         let mut min = [f64::INFINITY; 3];
         let mut max = [f64::NEG_INFINITY; 3];
         for vertex in &vertices[start..] {
             for a in 0..3 {
-                let value = f64::from(vertex.pos[a]) + self.camera[a];
+                let value = f64::from(vertex.pos[a]) + camera[a];
                 if !value.is_finite() {
-                    return false;
+                    return None;
                 }
                 min[a] = min[a].min(value);
                 max[a] = max[a].max(value);
             }
         }
         // Cover floating-point and rasterization edges as well as the vertices.
-        self.occluded(min.map(|v| v - 0.05), max.map(|v| v + 0.05), opaque)
+        Some((min.map(|v| v - 0.05), max.map(|v| v + 0.05)))
     }
 
     /// Returns true only when a complete opaque block plane covers the bounds.

crates/horizon-client/src/game/advancements.rs

@@ -4,7 +4,7 @@
 use super::{Dim, Game};
 use horizon_client::{
     advancements::{self as adv, EntityView, Frame, ItemView, Progress, Tree},
-    hud::HudBatch,
+    hud::{HudBatch, rgba},
     items::ItemStack,
     text::{self, Style, Text},
     toasts::Slide,
@@ -326,13 +326,19 @@ impl Game<'_> {
             return;
         }
         let data = self.options.resources.join("data");
-        // The world's packs' advancements go over the game's own.
-        let files = super::functions::content_overlay(
-            &self.world_root,
-            &self.options.resources,
-            self.cmds.vanilla_disabled,
-            &self.level.enabled_features,
-        );
+        // The world's packs' advancements go over the game's own, and a
+        // native mod's contributed files are already among them: the tables
+        // were built for this open (`build_world_tables`), so the hook is
+        // asked once, not again here.
+        let files = match &self.world_tables {
+            Some(tables) => tables.files.clone(),
+            None => super::functions::content_overlay(
+                &self.world_root,
+                &self.options.resources,
+                self.cmds.vanilla_disabled,
+                &self.level.enabled_features,
+            ),
+        };
         self.adv.pending_tree = std::thread::Builder::new()
             .name("horizon-advancements".into())
             .spawn(move || Tree::shared(&data, &horizon_world::loot::PackOverlay { files: &files }))
@@ -1821,11 +1827,7 @@ impl Game<'_> {
         }
         let atlas = &self.gui.atlas;
         batch.sprite(atlas, "gui/sprites/toast/advancement", x, y);
-        let (key, color) = match frame {
-            Frame::Task => ("advancements.toast.task", 0xFFFF_FF00),
-            Frame::Goal => ("advancements.toast.goal", 0xFFFF_FF00),
-            Frame::Challenge => ("advancements.toast.challenge", 0xFFFF_88FF),
-        };
+        let (key, color) = toast_label(frame);
         // AdvancementToast.extractRenderState: a title of one line sits under
         // the frame's label; a longer one is wrapped at 125, the label fading
         // out first (to 1.5 s) and the lines fading in after it over 0.3 s.
@@ -1862,6 +1864,15 @@ impl Game<'_> {
         self.draw_item(batch, &ItemStack::new(&icon, 1), x + 8.0, y + 8.0);
     }
 }
+/// The toast's frame label and its colour (`AdvancementToast`: -30465, pink,
+/// for a challenge, else -256, yellow), packed as `hud::rgba` for the batch.
+fn toast_label(frame: Frame) -> (&'static str, u32) {
+    match frame {
+        Frame::Task => ("advancements.toast.task", rgba(255, 255, 0, 255)),
+        Frame::Goal => ("advancements.toast.goal", rgba(255, 255, 0, 255)),
+        Frame::Challenge => ("advancements.toast.challenge", rgba(255, 136, 255, 255)),
+    }
+}
 /// `Advancement.name`: the bracketed title in the frame's colour, with the
 /// description on hover; the id when there is no display.
 pub(super) fn adv_name(a: &adv::Advancement) -> Text {
@@ -1995,7 +2006,7 @@ impl Game<'_> {
                     criteria.push(adv::Criterion {
                         name: name.clone(),
                         trigger: String::new(),
-                        conditions: Value::Null,
+                        conditions: Value::Null.into(),
                     });
                 }
             }
@@ -2059,6 +2070,18 @@ pub(super) fn text_of(v: &Value) -> Text {
 mod tests {
     use super::*;
 
+    #[test]
+    fn toast_labels_are_yellow_or_pink() {
+        // The batch takes colours as `rgba`: 0xFFFF_FF00 there is cyan (#5850).
+        for frame in [Frame::Task, Frame::Goal] {
+            assert_eq!(toast_label(frame).1.to_le_bytes(), [255, 255, 0, 255]);
+        }
+        assert_eq!(
+            toast_label(Frame::Challenge).1.to_le_bytes(),
+            [255, 136, 255, 255]
+        );
+    }
+
     fn recipes(n: usize) -> Toast {
         Toast::recipe(
             (0..n)

crates/horizon-client/src/game/agent.rs

@@ -417,6 +417,7 @@ impl Game<'_> {
             Screen::Advancements => "advancements",
             Screen::WorldOptions => "world-options",
             Screen::Friends => "friends",
+            Screen::Social => "social",
             Screen::ServerLinks => "server-links",
             Screen::ConfirmLink => "confirm-link",
             Screen::DialogWarning => "dialog-warning",
@@ -424,6 +425,7 @@ impl Game<'_> {
             Screen::BlockEditor => "block-editor",
             Screen::Win => "win",
             Screen::DebugOptions => "debug-options",
+            Screen::Mod => "mod",
         }
     }
     pub(super) fn inventory_counts(&self) -> BTreeMap<String, i64> {
@@ -498,7 +500,7 @@ impl Game<'_> {
         json!({
             "dialog": self.dialog_status(),
             "screen": self.screen_label(),
-            "menu": self.title.as_ref().map(|_| self.title_value()),
+            "menu": (self.title.is_some() || self.split_profiles_open()).then(|| self.title_value()),
             "world": (self.title.is_none()).then(|| match &self.integrated {
                 Some(server) => server.world_name.clone(),
                 None => self.level.name.clone(),
@@ -528,8 +530,16 @@ impl Game<'_> {
         })
     }
 
+    /// Splitscreen's profile page, a joining player's (`split_profiles`).
+    fn split_profiles_open(&self) -> bool {
+        self.screen == Screen::Options
+            && self.ui.options.page() == horizon_client::options_ui::Page::SplitProfiles
+    }
     fn title_value(&self) -> Value {
         use horizon_client::title::Mode;
+        if self.split_profiles_open() {
+            return self.ui.options.split_profiles.state();
+        }
         let Some(title) = &self.title else {
             return Value::Null;
         };
@@ -727,7 +737,7 @@ impl Game<'_> {
             v["chat_input"] = json!(chat.input.value);
             v["chat_suggestions"] = json!(chat.suggestions_visible());
         }
-        if self.title.is_some() {
+        if self.title.is_some() || self.split_profiles_open() {
             v["menu"] = self.title_value();
         }
         if self.screen == Screen::Inventory && self.title.is_none() {
@@ -1591,6 +1601,22 @@ impl Game<'_> {
                 self.synth_click(event_loop, x, y, button)?;
                 ok(json!({ "ok": true, "screen": self.screen_label() }))
             }
+            // Splitscreen's profile page, over a joining player's title screen.
+            "type" if self.split_profiles_open() => {
+                let text = line
+                    .trim_start()
+                    .strip_prefix("type")
+                    .unwrap_or("")
+                    .strip_prefix(' ')
+                    .unwrap_or("");
+                let page = &mut self.ui.options.split_profiles;
+                if text == "\\b" {
+                    page.key(winit::keyboard::KeyCode::Backspace, None);
+                } else {
+                    page.type_text(text);
+                }
+                ok(json!({ "ok": true, "menu": self.title_value() }))
+            }
             "type" if self.title.is_some() => {
                 // type [--field name|seed] [--replace] TEXT on the title screens.
                 let mut text = line

crates/horizon-client/src/game/armor_stands.rs

@@ -727,20 +727,20 @@ impl Game<'_> {
         true
     }
     pub(super) fn tick_armor_stands(&mut self) {
-        let mut scene = horizon_client::collisions::SceneCollisions {
-            world: &self.world,
-            binding: self.collision,
-            subject: None,
-        };
         let mut dead = Vec::new();
         // ServerLevel.tick: only entities in entity-ticking chunks tick.
         let ticking = self.entity_ticking_area();
-        for (i, a) in self.armor_stands.iter_mut().enumerate() {
-            a.previous = a.position;
-            a.previous_yaw = a.yaw;
-            if !ticking(a.position.x.floor() as i32, a.position.z.floor() as i32) {
+        for i in 0..self.armor_stands.len() {
+            let at = self.armor_stands[i].position;
+            if !ticking(at.x.floor() as i32, at.z.floor() as i32) {
+                self.armor_stands[i].previous = at;
+                self.armor_stands[i].previous_yaw = self.armor_stands[i].yaw;
                 continue;
             }
+            self.armor_stand_location_effects(i, false);
+            let a = &mut self.armor_stands[i];
+            a.previous = a.position;
+            a.previous_yaw = a.yaw;
             let in_water = a.update_fluids(&self.world, &self.res.motion().fluids);
             let (world, registry, facts, collision) = (
                 &self.world,
@@ -748,14 +748,31 @@ impl Game<'_> {
                 self.res.facts(),
                 self.collision,
             );
+            let mut scene = horizon_client::collisions::SceneCollisions {
+                world,
+                binding: collision,
+                subject: None,
+            };
             a.tick(&mut scene, facts, in_water, &mut |bounds, velocity| {
                 horizon_client::motion::bubble_column_push(
                     world, registry, facts, collision, bounds, velocity,
                 );
             });
+            if in_water {
+                a.enchantment_fall_distance = 0.0;
+            } else {
+                a.enchantment_fall_distance += (a.previous.y - a.position.y).max(0.0);
+            }
+            let landed = a.on_ground && a.enchantment_fall_distance > 0.0;
+            if a.on_ground {
+                a.enchantment_fall_distance = 0.0;
+            }
             if !a.environment_tick(&self.world, self.res.facts(), self.pack.assets.registry) {
                 dead.push(i);
             }
+            if landed {
+                self.armor_stand_location_effects(i, true);
+            }
         }
         for i in dead.into_iter().rev() {
             self.break_armor_stand_by_anything(i);

crates/horizon-client/src/game/block_entity_anims.rs

@@ -303,6 +303,7 @@ impl Game<'_> {
             .get("minecraft:conduit_effect_block")
             .cloned()
             .unwrap_or_default();
+        let mut shulker_pushes = Vec::new();
         for &(pos, ticker) in &positions {
             match ticker {
                 Ticker::Lid => self.be_anims.chests.entry(pos).or_default().tick(),
@@ -315,17 +316,19 @@ impl Game<'_> {
                         .tick(pos, &players, &mut anims.book_random);
                 }
                 Ticker::Shulker { facing } => {
-                    // A window that simulates the world ticks its boxes on the
-                    // server pass (`tick_block_entities`, which also applies
-                    // `moveCollidedEntities`); a server's client only animates
-                    // what it is sent. Either way the collision queries read
-                    // the lids from `World::shulkers` (`sync_shulkers`).
+                    // `ShulkerBoxBlockEntity.tick` runs on both sides: the
+                    // client moves its own player, including with a menu open.
+                    // The server ticks its boxes in `tick_block_entities`.
                     if self.remote.is_some() {
-                        self.be_anims
+                        let tick = self
+                            .be_anims
                             .shulkers
                             .entry(pos)
                             .or_default()
                             .tick(pos, facing);
+                        if let Some(push) = tick.push {
+                            shulker_pushes.push((pos, facing, push));
+                        }
                     }
                 }
                 Ticker::Skull { powered } => {
@@ -432,6 +435,10 @@ impl Game<'_> {
             }
         }
         self.be_anims.present = positions;
+        if self.remote.is_some() {
+            self.sync_shulkers();
+            self.push_shulker_entities(shulker_pushes);
+        }
     }
     /// `ConduitBlockEntity.serverTick` of every conduit in the chunks that
     /// tick blocks, with or without a renderer. The conduits are looked for

crates/horizon-client/src/game/block_items.rs

@@ -152,6 +152,31 @@ impl Game<'_> {
         Some(stack)
     }
 
+    /// `ShulkerBoxBlock.playerWillDestroy`: a Creative player's filled box is
+    /// one item at the block center, with collectComponents and the default pickup delay.
+    /// This direct spawn intentionally does not use the block_drops gamerule.
+    pub(super) fn drop_creative_shulker(&mut self, pos: [i32; 3]) {
+        let key = (pos[0], pos[1], pos[2]);
+        let filled = matches!(self.world.block_entities.get(&key), Some(BlockEntity::Chest(items))
+            if items.iter().flatten().any(|s| s.count > 0));
+        if !filled {
+            return;
+        }
+        let Some(saved) = self.saved_block_entity(key) else {
+            return;
+        };
+        let state = self.world.block(pos[0], pos[1], pos[2]);
+        let mut stack = ItemStack::new(&self.res.facts().get(state).item, 1);
+        let patch = block_entity_item::collected_components(&saved);
+        (stack.damage, stack.extra) = item_data::decode_components(Some(&Tag::Compound(patch)));
+        self.spawn_item(
+            stack,
+            pos.map(|v| f64::from(v) + 0.5),
+            super::dispenser::new_item_motion(),
+            10,
+        );
+    }
+
     /// `BlockItem.updateBlockStateFromTag`: the properties of the item's
     /// `block_state` component (a hive's honey level, a statue's pose) set on
     /// the block just placed at `pos`. Returns the state it has now.

crates/horizon-client/src/game/blockctl.rs

@@ -28,7 +28,10 @@ fn parse_state(text: &str) -> Result<BlockState> {
         let (k, v) = pair.split_once('=').ok_or("properties are key=value")?;
         properties.insert(k.to_owned(), v.to_owned());
     }
-    Ok(BlockState { name, properties })
+    Ok(BlockState {
+        name,
+        properties: properties.into(),
+    })
 }
 
 impl Game<'_> {