Merge remote-tracking branch 'origin/main' into layers/packs-entity

# Conflicts:
#	crates/horizon-client/src/client_lib.rs

AGENTS.md

@@ -75,6 +75,7 @@ Game workspace (root `Cargo.toml`); `launcher/` and `crates/horizon-telemetry-se
 | `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-polytone` | Polytone-format pack files (`assets/*/polytone/`), read clean-room from the public wiki: targets, biome and dimension modifiers and their environment attribute layers (#11486) |
+| `horizon-pack-options` | A resource pack's own options as the game lists and keeps them (entries, controls, values, presets), whatever pack format declares them; engine, no dependencies |
 | `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

@@ -1590,6 +1590,7 @@ dependencies = [
  "horizon-items",
  "horizon-narrator",
  "horizon-optifine",
+ "horizon-pack-options",
  "horizon-polytone",
  "horizon-protocol",
  "horizon-shader-api",
@@ -1650,6 +1651,15 @@ dependencies = [
  "ureq",
 ]
 
+[[package]]
+name = "horizon-discord"
+version = "0.1.0"
+dependencies = [
+ "horizon-platform",
+ "log",
+ "serde_json",
+]
+
 [[package]]
 name = "horizon-dualsense"
 version = "0.1.0"
@@ -1793,6 +1803,7 @@ dependencies = [
 name = "horizon-official"
 version = "0.1.0"
 dependencies = [
+ "horizon-discord",
  "horizon-friends",
  "horizon-game",
  "horizon-heartbeat",
@@ -1821,6 +1832,10 @@ dependencies = [
  "regex",
 ]
 
+[[package]]
+name = "horizon-pack-options"
+version = "0.1.0"
+
 [[package]]
 name = "horizon-platform"
 version = "0.1.0"
@@ -1838,6 +1853,7 @@ dependencies = [
 name = "horizon-polytone"
 version = "0.1.0"
 dependencies = [
+ "horizon-pack-options",
  "log",
  "regex",
  "serde_json",

Cargo.toml

@@ -34,6 +34,7 @@ members = [
     "crates/horizon-game",
     "crates/horizon-official",
     "crates/horizon-heartbeat",
+    "crates/horizon-discord",
     "crates/horizon-official-servers",
     "crates/horizon-bench",
     "crates/horizon-friends",
@@ -46,6 +47,7 @@ members = [
     "crates/horizon-shaders",
     "crates/horizon-optifine",
     "crates/horizon-polytone",
+    "crates/horizon-pack-options",
     "crates/horizon-shader-api",
     "crates/horizon-release-sign",
     "crates/horizon-mod-deps",

crates/horizon-client-input/Cargo.toml

@@ -9,11 +9,13 @@ description = "The client's input layer: key bindings and their names, mouse, co
 [dependencies]
 horizon-client-core = { path = "../horizon-client-core" }
 winit = "0.30.13"
-# The window icon.
-horizon-theme = { path = "../horizon-theme" }
 png = "0.18"
 arboard = { version = "3.6.1", default-features = false, features = ["wayland-data-control"] }
 
+[dev-dependencies]
+# The window icon test decodes Horizon's icon.
+horizon-theme = { path = "../horizon-theme" }
+
 [features]
 controllers = []
 

crates/horizon-client-input/src/window.rs

@@ -638,10 +638,30 @@ pub fn fullscreen_request(
     }
 }
 
-/// Horizon's icon for the window's title bar and the task bar (X11 and Windows; Wayland takes
-/// it from the `horizon.desktop` entry, macOS from the app bundle). `None` if it can't be read.
+/// The PNG the windows show as their icon, given once at startup by the layer that brands the
+/// game (the engine has none of its own).
+static ICON_PNG: std::sync::OnceLock<&'static [u8]> = std::sync::OnceLock::new();
+
+/// Give the windows their icon, a PNG: call it before the first window opens. A second call
+/// keeps the first icon.
+pub fn set_icon_png(png: &'static [u8]) {
+    let _ = ICON_PNG.set(png);
+}
+
+/// The icon given to [`set_icon_png`], if any.
+pub fn icon_png() -> Option<&'static [u8]> {
+    ICON_PNG.get().copied()
+}
+
+/// The icon for the window's title bar and the task bar (X11 and Windows; Wayland takes it from
+/// the `.desktop` entry, macOS from the app bundle). `None` with no icon given, or one that
+/// can't be read.
 pub fn icon() -> Option<winit::window::Icon> {
-    let mut decoder = png::Decoder::new(std::io::Cursor::new(horizon_theme::ICON_PNG));
+    decode_icon(icon_png()?)
+}
+
+fn decode_icon(png: &[u8]) -> Option<winit::window::Icon> {
+    let mut decoder = png::Decoder::new(std::io::Cursor::new(png));
     decoder.ignore_checksums(true);
     decoder.set_transformations(png::Transformations::EXPAND | png::Transformations::STRIP_16);
     let mut reader = decoder.read_info().ok()?;
@@ -654,14 +674,15 @@ pub fn icon() -> Option<winit::window::Icon> {
     winit::window::Icon::from_rgba(bytes, info.width, info.height).ok()
 }
 
-/// Apply Horizon's icon to every window. Windows has a separate taskbar icon slot from the small
-/// window icon; requiring the decoded icon there prevents a generic taskbar icon from appearing.
-pub fn with_horizon_icon(
-    attributes: winit::window::WindowAttributes,
-) -> winit::window::WindowAttributes {
+/// Apply the icon given to [`set_icon_png`] to a window. Windows has a separate taskbar icon slot
+/// from the small window icon; requiring a given icon to decode there prevents a generic taskbar
+/// icon from appearing.
+pub fn with_icon(attributes: winit::window::WindowAttributes) -> winit::window::WindowAttributes {
+    #[cfg(not(target_os = "windows"))]
     let icon = icon();
     #[cfg(target_os = "windows")]
-    let icon = Some(icon.expect("Horizon's icon must be available on Windows"));
+    let icon =
+        icon_png().map(|png| decode_icon(png).expect("the window icon must decode on Windows"));
 
     let attributes = attributes.with_window_icon(icon.clone());
     #[cfg(target_os = "windows")]
@@ -739,7 +760,8 @@ mod tests {
     }
     #[test]
     fn the_window_icon_decodes() {
-        assert!(icon().is_some());
+        assert!(decode_icon(horizon_theme::ICON_PNG).is_some());
+        assert!(decode_icon(b"not a png").is_none());
     }
 
     #[test]

crates/horizon-client-lib/Cargo.toml

@@ -70,7 +70,6 @@ flate2 = { version = "1.1.10", default-features = false, features = ["zlib-rs",
 mio = { version = "1.2.4", features = ["os-poll", "net"] }
 # Shared chunk frames are found by one keyed 128-bit hash of their body (lan/conn.rs SharedFrames).
 xxhash-rust = { version = "0.8.19", features = ["xxh3"] }
-horizon-theme = { path = "../horizon-theme" }
 # Opt-in data collection: the game keeps, the launcher sends (docs/telemetry.md).
 horizon-telemetry = { path = "../horizon-telemetry", default-features = false }
 horizon-bench = { path = "../horizon-bench" }
@@ -109,16 +108,12 @@ objc2-foundation = { version = "0.3", default-features = false, features = ["std
 wgpu = { version = "30.0.1", default-features = false, features = ["gles"] }
 
 [features]
-default = ["audio", "controllers", "horizon-extras"]
+default = ["audio", "controllers"]
 # Sound output. Without it (and `controllers`) the program links neither libasound nor libudev on
 # Linux: the server build (`--no-default-features`, released as horizon-engine; docs/server.md).
 audio = ["horizon-client-render/audio"]
 # Controllers: gilrs, and the DualSense's own output. Without it only `horizon-ctl pad`'s virtual pad.
 controllers = ["dep:gilrs", "horizon-client-input/controllers"]
-# Horizon's own parts still in this crate (docs/forking.md, docs/layers.md): the features below.
-horizon-extras = ["discord"]
-# "Playing Horizon" on the player's Discord profile (`discord_presence`).
-discord = []
 # Records the call sites of mob random draws (`mob_ai_probe` traces).
 rng-trace = ["horizon-core/rng-trace"]
 # Compatibility with earlier experiment commands: main already uses mimalloc.
@@ -130,6 +125,8 @@ windows-segment-heap = []
 workspace = true
 
 [dev-dependencies]
+# ui_theme's unit tests draw text in the design system's fonts.
+horizon-theme = { path = "../horizon-theme" }
 horizon-client-render = { path = "../horizon-client-render", features = ["test-support"] }
 horizon-items = { path = "../horizon-items", features = ["test-support"] }
 # Every WGSL shader translated as wgpu's DirectX 12 backend does (gfx.rs tests).

crates/horizon-client-render/Cargo.toml

@@ -24,12 +24,12 @@ 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-pack-options = { path = "../horizon-pack-options" }
 horizon-polytone = { path = "../horizon-polytone" }
 horizon-protocol = { path = "../horizon-protocol" }
 horizon-shader-api = { path = "../horizon-shader-api" }
 horizon-shaders = { path = "../horizon-shaders" }
 horizon-system = { path = "../horizon-system" }
-horizon-theme = { path = "../horizon-theme" }
 horizon-threads = { path = "../horizon-threads" }
 horizon-world = { path = "../horizon-world" }
 ab_glyph = "0.2.32"
@@ -85,5 +85,7 @@ horizon-extras = []
 workspace = true
 
 [dev-dependencies]
+# Tests: a TrueType font to load, and the design system the menus' motion curves match.
+horizon-theme = { path = "../horizon-theme" }
 horizon-items = { path = "../horizon-items", features = ["test-support"] }
 naga = { version = "30.0.1", features = ["wgsl-in", "hlsl-out", "glsl-out", "msl-out", "spv-out"] }

crates/horizon-client-render/examples/pack_load_bench.rs

@@ -288,6 +288,8 @@ fn zip_pack(id: &str, path: PathBuf) -> Pack {
 }
 
 fn main() {
+    // The pack formats the game installs at startup, so their loading is measured too.
+    horizon_client_render::pack_formats::install();
     let args: Vec<String> = std::env::args().collect();
     let scale = args
         .iter()

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

@@ -99,10 +99,8 @@ 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,
-    /// Fusion connected textures (empty without Fusion's connecting textures and models).
-    pub fusion: crate::fusion::FusionTextures,
+    /// The packs' connected textures (OptiFine's, Fusion's), when they have some.
+    pub connected: Option<crate::connected::Connected>,
     /// Counts up each time resources load, from 1: a native mod asks again where blocks'
     /// sprites are when it changes (`native_block_sprites_version`).
     pub generation: u64,
@@ -345,40 +343,27 @@ impl RenderAssets {
             sprites.insert(root, &format!("minecraft:block/destroy_stage_{stage}"))?;
             sprites.insert(root, &format!("minecraft:block/destroy_oit_stage_{stage}"))?;
         }
-        let fusion = if draws {
-            let _step = crate::spans::startup::step("core.fusion");
-            crate::fusion::FusionTextures::load(root, registry, &mut sprites, &mut models.catalog)
-        } else {
-            Default::default()
-        };
         let mut emissive = Vec::new();
         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(
+            // Native mods' emissive textures go where the pack format puts them (after its
+            // models' tiles, before its rules' tiles), else after both.
+            let mut native_loaded = false;
+            let mut native = |sprites: &mut crate::sprites::Sprites| {
+                if !std::mem::replace(&mut native_loaded, true) {
+                    crate::native_emissive::load(root, sprites);
+                }
+            };
+            let connected = crate::pack_hooks::formats().connected_textures(
                 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)
-                },
-            )
+                &mut models.catalog,
+                &mut native,
+            );
+            native(&mut sprites);
+            connected
         } else {
-            Default::default()
+            None
         };
         // After the connected tiles: a tile identical to a block shares its layer, and the
         // overlays skip shared layers.
@@ -411,7 +396,6 @@ impl RenderAssets {
             pbr_specular: sprites.specular,
             pbr_size: sprites.pbr_size,
             connected,
-            fusion,
             generation: GENERATION.fetch_add(1, std::sync::atomic::Ordering::Relaxed) + 1,
         })
     }

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

@@ -960,7 +960,7 @@ pub struct Scene<'a> {
     pub world: &'a World,
     pub sprites: &'a HashMap<String, Rect>,
     /// The packs' OptiFine emissive overlays of the sprites.
-    pub emissive: &'a horizon_optifine::emissive::Emissive,
+    pub emissive: &'a crate::entity_textures::Emissive,
     /// Atlas sprites that contain a texel with fractional alpha. Static
     /// geometry stays on the cutout pipeline; these models keep the blended
     /// entity path so resource packs retain their alpha behavior.
@@ -1039,7 +1039,7 @@ impl CacheOptions {
     }
 }
 /// The block-entity models and what is baked from them: vanilla's, or the packs' custom entity
-/// models over them ([`crate::block_entity_cem`]).
+/// models over them ([`crate::pack_hooks::PackFormats::block_entity_models`]).
 #[derive(Default)]
 pub struct BlockEntityShapes {
     models: HashMap<&'static str, ModelPart>,
@@ -1555,7 +1555,7 @@ impl BlockEntityRenderer {
     /// The models the packs under `root` give, their `.jem` files over vanilla's, for
     /// [`Self::set_shapes`] (a pack reload): vanilla's own, shared, without any.
     pub fn shapes_for(&self, root: &Path) -> Arc<BlockEntityShapes> {
-        match crate::block_entity_cem::reshape(root, &self.vanilla.models) {
+        match crate::pack_hooks::formats().block_entity_models(root, &self.vanilla.models) {
             Some((models, textures)) => Arc::new(BlockEntityShapes::new(models, textures)),
             None => self.vanilla.clone(),
         }
@@ -4768,7 +4768,8 @@ mod tests {
 
     #[test]
     fn a_chest_jem_reshapes_the_closed_chest_and_paints_its_texture() {
-        use crate::block_entity_cem::tests::{BOX, chest, pack};
+        use crate::pack_formats::block_entity_cem::tests::{BOX, chest, pack};
+        crate::pack_formats::install();
         let vanilla = Arc::new(BlockEntityShapes::new(
             HashMap::from([("chest", chest())]),
             HashMap::new(),
@@ -4864,8 +4865,8 @@ mod tests {
         };
         // The chest's three faces become the bottom's, the lock's and the custom lid's six, in
         // the `.jem`'s texture. Ender and copper chests have no file of their own: vanilla's
-        // three faces in their own textures. (Trapped chests: `block_entity_cem`'s tests; their
-        // texture turns festive in late December.)
+        // three faces in their own textures. (Trapped chests: `block_entity_cem`'s tests in
+        // `pack_formats`; their texture turns festive in late December.)
         for (block, texture, u0, faces) in [
             ("chest", "entity/chest/normal", 0.4, 8),
             ("ender_chest", "entity/chest/ender", 0.2, 3),

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

@@ -1,116 +1,157 @@
-//! 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.
+//! Custom item textures: rules a pack format vanilla doesn't read (OptiFine's and CIT Resewn's
+//! `cit/` folders) gives, which change a stack's texture, model, worn armour layers or
+//! enchantment glint. The platform's pack formats read and match them ([`crate::pack_hooks`]);
+//! the engine draws what the matching rule says ([`Rule`]).
 
-pub use horizon_optifine::cit::{Hand, Kind, Rule};
-
-use crate::cit_glint::{Global, StackGlint};
-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::{Arc, Mutex};
+use std::sync::Arc;
 
-/// 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| {
-            let props = read_properties(&root.join(&path))?;
-            let rule = Rule::parse(&path, &props, |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
+use horizon_items::items::ItemStack;
+
+use crate::cit_glint::StackGlint;
+
+/// What a rule changes.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum Kind {
+    Item,
+    Armor,
+    Elytra,
+    Enchantment,
 }
 
-/// A `.properties` file as CIT Resewn reads them (`Properties::parse_equals_first`): UTF-8,
-/// else Latin-1 as Java reads them, so a pack saved that way still loads. `None` when it can't
-/// be read.
-pub fn read_properties(path: &Path) -> Option<Properties> {
-    let bytes = fs::read(path).ok()?;
-    let text = String::from_utf8(bytes)
-        .unwrap_or_else(|e| e.into_bytes().iter().map(|&b| char::from(b)).collect());
-    Some(Properties::parse_equals_first(&text))
+/// The hand a stack is drawn in; GUI items count as the main hand. `Any` is a rule's "either".
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum Hand {
+    Any,
+    Main,
+    Off,
 }
 
-/// The rules with an index by item and a cache of what each stack matched.
-#[derive(Debug, Default)]
+/// An OpenGL blend factor (`GL_ONE`, `GL_SRC_ALPHA`...), as `glBlendFuncSeparate` takes them.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum Factor {
+    Zero,
+    One,
+    SrcColor,
+    OneMinusSrcColor,
+    SrcAlpha,
+    OneMinusSrcAlpha,
+    DstAlpha,
+    OneMinusDstAlpha,
+    DstColor,
+    OneMinusDstColor,
+    SrcAlphaSaturate,
+}
+
+/// A glint layer's blend factors for colour and alpha.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub struct Blend {
+    pub src: Factor,
+    pub dst: Factor,
+    pub src_alpha: Factor,
+    pub dst_alpha: Factor,
+}
+
+/// An enchantment rule's glint layer.
+#[derive(Clone, Debug, PartialEq)]
+pub struct Glint {
+    pub layer: i32,
+    /// `None` draws without blending (replace).
+    pub blend: Option<Blend>,
+    /// Scroll speed: the texture runs through vanilla's glint periods at `speed` times the
+    /// clock in milliseconds.
+    pub speed: f32,
+    /// Degrees the texture turns by.
+    pub rotation: f32,
+    /// Seconds on this layer when the layers take turns.
+    pub duration: f32,
+    /// Multipliers of the texture's colour, never negative.
+    pub rgba: [f32; 4],
+    /// Whether the default glint still draws under this layer.
+    pub use_glint: bool,
+    /// Linear filtering, else nearest.
+    pub blur: bool,
+}
+
+/// A rule as the engine draws it.
+#[derive(Clone, Debug, PartialEq)]
+pub struct Rule {
+    /// The rule's file, as a resource path.
+    pub path: String,
+    pub kind: Kind,
+    /// Its texture, as a resource path to a `.png`.
+    pub texture: Option<String>,
+    /// Its named textures: (name, resource path).
+    pub textures: Vec<(String, String)>,
+    /// Its model, as a resource path to a `.json`.
+    pub model: Option<String>,
+    /// Its named models.
+    pub models: Vec<(String, String)>,
+    /// What an Enchantment rule draws.
+    pub glint: Glint,
+}
+
+/// Which rules a stack matches: the pack format's own conditions.
+pub trait Matcher: Send + Sync {
+    /// The winning rule of `kind` (Item, Armor or Elytra) for this stack, as an index into
+    /// [`CitRules::rules`].
+    fn select(&self, kind: Kind, stack: &ItemStack, hand: Hand, max_damage: u32) -> Option<usize>;
+    /// Every matching Enchantment rule for the stack drawn in `hand`, in priority order.
+    fn enchantments(&self, stack: &ItemStack, hand: Hand, max_damage: u32) -> Vec<usize>;
+    /// The glint layers this stack draws in `hand`; `None` when the pack changes no glint.
+    /// `foil` is whether the stack draws a glint at all.
+    fn glint(
+        &self,
+        stack: &ItemStack,
+        hand: Hand,
+        max_damage: u32,
+        foil: bool,
+    ) -> Option<Arc<StackGlint>>;
+    /// Leave out the Enchantment rules `keep` refuses: they match no stack.
+    fn keep_glints(&mut self, keep: &dyn Fn(usize) -> bool);
+}
+
+/// The packs' custom item texture rules, the winner first, and their matcher.
 pub struct CitRules {
     pub rules: Vec<Rule>,
-    /// The pack's `cit.properties`.
-    pub global: Global,
-    /// 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>>>,
-    glints: Mutex<HashMap<u64, Arc<StackGlint>>>,
+    /// Whether the default glint draws on items no enchantment rule matches.
+    pub use_glint: bool,
+    matcher: Option<Box<dyn Matcher>>,
 }
 
-#[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 {
+impl Default for CitRules {
+    fn default() -> Self {
         Self {
-            global: crate::cit_glint::load_global(root),
-            ..Self::new(load_rules(root))
+            rules: Vec::new(),
+            use_glint: true,
+            matcher: None,
         }
     }
+}
 
-    /// `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();
+impl std::fmt::Debug for CitRules {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("CitRules")
+            .field("rules", &self.rules)
+            .field("use_glint", &self.use_glint)
+            .finish_non_exhaustive()
+    }
+}
+
+impl CitRules {
+    /// The rules of the overlay at `root`, from the installed pack formats.
+    pub fn load(root: &Path) -> Self {
+        crate::pack_hooks::formats()
+            .item_textures(root)
+            .unwrap_or_default()
+    }
+
+    /// `rules`, in priority order, matched by `matcher`.
+    pub fn new(rules: Vec<Rule>, use_glint: bool, matcher: Box<dyn Matcher>) -> Self {
         Self {
             rules,
-            by_item,
-            any_item,
-            literals,
-            ..Default::default()
+            use_glint,
+            matcher: Some(matcher),
         }
     }
 
@@ -121,17 +162,12 @@ impl CitRules {
     /// Leave out the Enchantment rules `keep` refuses (those without a drawable texture): they
     /// match no stack, so vanilla's glint and the other rules of their layer stay.
     pub fn keep_glints(&mut self, keep: impl Fn(usize) -> bool) {
-        self.any_item.retain(|&i| keep(i as usize));
-        let named = &mut self.by_item[Kind::Enchantment as usize];
-        for list in named.values_mut() {
-            list.retain(|&i| keep(i as usize));
+        if let Some(matcher) = &mut self.matcher {
+            matcher.keep_glints(&keep);
         }
-        named.retain(|_, list| !list.is_empty());
-        lock(&self.enchanted).clear();
-        lock(&self.glints).clear();
     }
 
-    /// The winning rule of `kind` (Item, Armor or Elytra) for this stack, as an index into `rules`.
+    /// [`Matcher::select`].
     pub fn select(
         &self,
         kind: Kind,
@@ -139,51 +175,17 @@ impl CitRules {
         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, hand, max_damage, comps.as_ref()));
-        remember(&self.selected, key, found);
-        found.map(|i| i as usize)
+        self.matcher.as_ref()?.select(kind, stack, hand, max_damage)
     }
 
-    /// Every matching Enchantment rule for the stack drawn in `hand` (`Hand::Main` for one in a
-    /// GUI), in priority order.
+    /// [`Matcher::enchantments`].
     pub fn enchantments(&self, stack: &ItemStack, hand: Hand, 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),
-            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, hand, max_damage, comps.as_ref()));
-            remember(&self.enchanted, key, all.clone());
-            all
-        });
-        found.into_iter().map(|i| i as usize).collect()
+        self.matcher
+            .as_ref()
+            .map_or_else(Vec::new, |m| m.enchantments(stack, hand, max_damage))
     }
 
-    /// The glint layers this stack draws in `hand` (`Hand::Main` in a GUI) and whether
-    /// vanilla's still does (`StackGlint`), worked out once per stack and hand; `None` when the
-    /// pack changes no glint. `foil` is whether the stack draws a glint at all
-    /// (`ItemStack::has_foil`): one that doesn't gets no layers.
+    /// [`Matcher::glint`].
     pub fn glint(
         &self,
         stack: &ItemStack,
@@ -191,659 +193,6 @@ impl CitRules {
         max_damage: u32,
         foil: bool,
     ) -> Option<Arc<StackGlint>> {
-        let no_rules =
-            self.any_item.is_empty() && self.by_item[Kind::Enchantment as usize].is_empty();
-        // Before the cache, which `foil` is not part of.
-        if !foil || (no_rules && self.global.use_glint) {
-            return None;
-        }
-        let comps = encode_components(stack);
-        let key = cache_key(
-            (2, Kind::Enchantment, hand),
-            stack,
-            max_damage,
-            comps.as_ref(),
-        );
-        if let Some(hit) = lock(&self.glints).get(&key) {
-            return Some(hit.clone());
-        }
-        let matched = self.enchantments(stack, hand, max_damage);
-        let glint = Arc::new(StackGlint::new(
-            &self.rules,
-            &matched,
-            stack.crafting_enchantments(),
-            &self.global,
-        ));
-        remember(&self.glints, key, glint.clone());
-        Some(glint)
-    }
-
-    /// Whether rule `i` matches the stack drawn in `hand`.
-    fn matches(
-        &self,
-        i: u32,
-        stack: &ItemStack,
-        hand: Hand,
-        max_damage: u32,
-        comps: Option<&Tag>,
-    ) -> bool {
-        let rule = &self.rules[i as usize];
-        if rule.hand != Hand::Any && rule.hand != hand {
-            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`, `enchantments` and `glint` apart.
-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, Hand::Main, 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);
-    }
-
-    /// `CitRules::glint` in the main hand, with the stack's own `has_foil` as callers pass it.
-    fn glint(cit: &CitRules, stack: &ItemStack, item_glint: bool) -> Option<Arc<StackGlint>> {
-        cit.glint(stack, Hand::Main, 0, stack.has_foil(item_glint))
-    }
-
-    /// `stack` with its `enchantment_glint_override` set to `on`.
-    fn overridden(mut stack: ItemStack, on: bool) -> ItemStack {
-        let flag = (
-            "minecraft:enchantment_glint_override".to_owned(),
-            Tag::Byte(on.into()),
-        );
-        stack.data_mut().other.push(flag);
-        stack
-    }
-
-    #[test]
-    fn a_stack_glint_reads_the_book_and_the_pack_file() {
-        let mut cit = rules(&[
-            ("sharp", "type=enchantment\nenchantments=sharpness"),
-            (
-                "keep",
-                "type=enchantment\nlayer=1\nuseGlint=true\nenchantments=mending",
-            ),
-        ]);
-        // An enchanted book's glint follows its stored enchantments.
-        let mut book = new("enchanted_book");
-        book.data_mut().stored_enchantments = vec![
-            (Arc::from("minecraft:sharpness"), 3),
-            (Arc::from("minecraft:mending"), 1),
-        ];
-        let book = glint(&cit, &book, true).unwrap();
-        let weights: Vec<_> = book.layers.iter().map(|l| l.weight).collect();
-        assert_eq!(weights, [0.75, 0.25]);
-        assert!(book.vanilla);
-        let plain = glint(&cit, &enchanted("stick", &[("sharpness", 1)]), false).unwrap();
-        assert_eq!(plain.layers.len(), 1);
-        assert!(!plain.vanilla);
-        // No enchantment rules: nothing changes, unless the pack turns vanilla's glint off.
-        let mut bare = rules(&[("stick", "items=stick")]);
-        assert!(glint(&bare, &overridden(new("stick"), true), false).is_none());
-        bare.global.use_glint = false;
-        assert!(
-            !glint(&bare, &overridden(new("stick"), true), false)
-                .unwrap()
-                .vanilla
-        );
-        cit.global.use_glint = false;
-        assert!(
-            glint(&cit, &overridden(new("stick"), true), false)
-                .unwrap()
-                .is_empty()
-        );
-    }
-
-    #[test]
-    fn only_a_stack_with_a_glint_gets_layers() {
-        let cit = rules(&[("any", "type=enchantment")]);
-        assert!(glint(&cit, &new("stick"), false).is_none());
-        // The override turns an enchanted stack's glint off, and an unenchanted one's on.
-        let off = overridden(enchanted("stick", &[("sharpness", 1)]), false);
-        assert!(glint(&cit, &off, false).is_none());
-        let on = glint(&cit, &overridden(new("stick"), true), false).unwrap();
-        let weights: Vec<_> = on.layers.iter().map(|l| l.weight).collect();
-        assert_eq!(
-            weights,
-            [1.0],
-            "nothing to share: the rule at full strength"
-        );
-        // The same stack, asked again without its glint, is not answered from the cache.
-        assert!(
-            cit.glint(&overridden(new("stick"), true), Hand::Main, 0, false)
-                .is_none()
-        );
-    }
-
-    #[test]
-    fn a_rule_left_out_of_the_glints_matches_nothing() {
-        let mut cit = rules(&[
-            ("broken", "type=enchantment\nitems=diamond_sword\nweight=1"),
-            ("shown", "type=enchantment"),
-        ]);
-        let sword = enchanted("diamond_sword", &[("sharpness", 1)]);
-        let layers = |cit: &CitRules| -> Vec<String> {
-            let glint = glint(cit, &sword, false).unwrap();
-            let stems = glint
-                .layers
-                .iter()
-                .map(|l| stem(cit, Some(l.rule)).unwrap());
-            stems.map(str::to_owned).collect()
-        };
-        // The heavier rule wins the layer, until its texture is missing.
-        assert_eq!(layers(&cit), ["broken"]);
-        let broken = (0..cit.rules.len())
-            .find(|&i| stem(&cit, Some(i)) == Some("broken"))
-            .unwrap();
-        cit.keep_glints(|i| i != broken);
-        assert_eq!(layers(&cit), ["shown"]);
-        assert_eq!(cit.enchantments(&sword, Hand::Main, 0).len(), 1);
-        // None left: vanilla's glint stays.
-        cit.keep_glints(|_| false);
-        assert!(glint(&cit, &sword, false).is_none());
-    }
-
-    #[test]
-    fn an_off_hand_layer_draws_only_in_the_off_hand() {
-        let cit = rules(&[
-            ("left", "type=enchantment\nlayer=1\nhand=off"),
-            ("both", "type=enchantment"),
-        ]);
-        let sword = enchanted("diamond_sword", &[("sharpness", 1)]);
-        let layers = |hand| -> Vec<&str> {
-            let glint = cit.glint(&sword, hand, 0, true).unwrap();
-            glint
-                .layers
-                .iter()
-                .map(|l| stem(&cit, Some(l.rule)).unwrap())
-                .collect()
-        };
-        assert_eq!(layers(Hand::Off), ["both", "left"]);
-        // Asked in this order, a cache keyed without the hand would answer as for the off hand.
-        assert_eq!(layers(Hand::Main), ["both"]);
+        self.matcher.as_ref()?.glint(stack, hand, max_damage, foil)
     }
 }

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

@@ -6,8 +6,8 @@
 //! chestplate, boots) and `entity/equipment/humanoid_leggings/diamond` (layer 2), so the layers
 //! are mapped back to the old names here. An elytra rule's `texture` replaces the wings'.
 
+use crate::cit::{Kind, Rule};
 use crate::cit_assets::{rule_sprites, sprite_id};
-use horizon_optifine::cit::{Kind, Rule};
 use std::collections::BTreeSet;
 
 /// The pre-1.21.2 armour texture name of an equipment asset's layer: `asset` (`minecraft:gold`
@@ -114,10 +114,9 @@ pub fn armor_sprites(rules: &[Rule]) -> BTreeSet<String> {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use horizon_optifine::Properties;
 
     fn rule(path: &str, text: &str) -> Rule {
-        Rule::parse(path, &Properties::parse_equals_first(text), |_| true).unwrap()
+        crate::pack_formats::cit::parse_rule(path, text).unwrap()
     }
 
     #[test]

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

@@ -5,8 +5,8 @@
 //! `horizon_cit:minecraft/optifine/cit/swords/flame`). A file already under `textures/` (or
 //! `models/`) keeps its vanilla id, so it is not packed twice.
 
+use crate::cit::{Kind, Rule};
 use horizon_assets::model::{CuboidModel, TextureSlot};
-use horizon_optifine::cit::{Kind, Rule};
 use std::collections::{BTreeMap, BTreeSet};
 use std::fs;
 use std::path::Path;
@@ -55,7 +55,7 @@ pub fn model_id(resource: &str) -> Option<String> {
 /// and for one that would leave the resource root (a pack model may write any id).
 pub fn resource(id: &str, ext: &str) -> Option<String> {
     let rest = id.strip_prefix(NAMESPACE)?.strip_prefix(':')?;
-    horizon_optifine::paths::valid(rest).then(|| format!("assets/{rest}.{ext}"))
+    stays_in_root(rest).then(|| format!("assets/{rest}.{ext}"))
 }
 
 /// Sprite ids the rules whose kind passes `keep` draw: their `texture` and `texture.<name>`
@@ -102,7 +102,14 @@ fn relative(file: &str, value: &str, ext: &str) -> Option<String> {
         .and_then(|r| r.strip_suffix('.'))
         .unwrap_or(rest);
     let path = format!("{dir}/{rest}.{ext}");
-    horizon_optifine::paths::valid(&path).then_some(path)
+    stays_in_root(&path).then_some(path)
+}
+
+/// Whether a resource path stays in the root: no `.`, `..` or empty segment, and no `\` (a
+/// separator on Windows, where `..\..` would climb).
+fn stays_in_root(path: &str) -> bool {
+    path.split('/')
+        .all(|segment| !matches!(segment, "" | "." | "..") && !segment.contains('\\'))
 }
 
 /// The id a relative value of the model at `file` names, as `CuboidModel::from_json` read it
@@ -294,11 +301,11 @@ mod tests {
             "base.json",
             r#"{"parent":"item/handheld","textures":{"layer2":"./glow.png"}}"#,
         );
-        let props =
-            horizon_optifine::Properties::parse_equals_first("items=stick\nmodel=./swords/flame");
-        let rule = Rule::parse("assets/minecraft/optifine/cit/a.properties", &props, |p| {
-            root.join(p).is_file()
-        })
+        let rule = crate::pack_formats::cit::parse_rule_in(
+            &root,
+            "assets/minecraft/optifine/cit/a.properties",
+            "items=stick\nmodel=./swords/flame",
+        )
         .unwrap();
         let models = load_models(&root, &[rule]);
         let _ = fs::remove_dir_all(&root);

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

@@ -1,26 +1,6 @@
-//! Custom Item Textures' enchantment glints (`type=enchantment`): which of a stack's matching
-//! rules draw, in which order and how strongly, and whether vanilla's glint still draws under
-//! them. The pack's `cit.properties` (`Global`) says how layers share an item.
-//!
-//! Written from OptiFine's `cit.properties` doc and CIT Resewn's (MIT) `TypeEnchantment` of
-//! before its 1.21.11 port, which implemented `method`, `cap` and `fade`: the sums and the
-//! cycle's fading follow it, except where noted.
-
-pub use horizon_optifine::cit::{Global, Method};
-
-use crate::cit::read_properties;
-use horizon_optifine::cit::Rule;
-use std::path::Path;
-
-/// The pack's global `cit.properties` under the overlay resource root: the first of
-/// `Global::PATHS` that exists, else the defaults.
-pub fn load_global(root: &Path) -> Global {
-    Global::PATHS
-        .iter()
-        .find_map(|path| read_properties(&root.join(path)))
-        .map(|props| Global::parse(&props))
-        .unwrap_or_default()
-}
+//! Custom item textures' enchantment glints: the layers a stack draws over (or instead of)
+//! vanilla's glint, and how strongly each draws over time. Which layers a stack gets is the pack
+//! format's ([`crate::cit::Matcher::glint`]); a layer's look is its rule's [`crate::cit::Glint`].
 
 /// One glint layer a stack draws.
 #[derive(Clone, Copy, Debug, PartialEq)]
@@ -33,6 +13,17 @@ pub struct GlintLayer {
     duration: f32,
 }
 
+impl GlintLayer {
+    /// Rule `rule`'s layer at `weight`, on for `duration` seconds when the layers take turns.
+    pub fn new(rule: usize, weight: f32, duration: f32) -> Self {
+        Self {
+            rule,
+            weight,
+            duration,
+        }
+    }
+}
+
 /// What a stack's glint is made of, worked out when the stack changes.
 #[derive(Clone, Debug, Default, PartialEq)]
 pub struct StackGlint {
@@ -45,84 +36,14 @@ pub struct StackGlint {
 }
 
 impl StackGlint {
-    /// The layers among `matched` (the stack's matching enchantment rules, in priority order,
-    /// as `CitRules::enchantments` gives them) that draw, for a stack with `enchantments`
-    /// (`ItemStack::crafting_enchantments`).
-    pub fn new(
-        rules: &[Rule],
-        matched: &[usize],
-        enchantments: &[(impl AsRef<str>, u32)],
-        global: &Global,
-    ) -> Self {
-        // The highest priority rule of each layer.
-        let mut layers: Vec<usize> = Vec::new();
-        for &i in matched {
-            let layer = rules[i].glint.layer;
-            if !layers.iter().any(|&j| rules[j].glint.layer == layer) {
-                layers.push(i);
-            }
-        }
-        layers.sort_by_key(|&i| rules[i].glint.layer);
-        let cycle = global.method == Method::Cycle;
-        // OptiFine's doc: `cap` is for `average` and `layered`, and keeps the topmost layers.
-        // `none`, which OptiFine lacks, is capped too, as CIT Resewn caps every method (it keeps
-        // the bottom layers, though, and caps cycles as well).
-        if let Some(cap) = global.cap.filter(|_| !cycle) {
-            let cap = usize::try_from(cap).unwrap_or(usize::MAX);
-            layers = layers.split_off(layers.len().saturating_sub(cap));
-        }
-        // CIT Resewn: any layer left asking for vanilla's glint keeps it, and the global
-        // `useGlint=false` removes it everywhere, as OptiFine's doc says too. `cap=0` leaves no
-        // custom layer, and vanilla's glint only if the pack's `useGlint` allows it.
-        let vanilla = global.use_glint
-            && (layers.is_empty() || layers.iter().any(|&i| rules[i].glint.use_glint));
-        // CIT Resewn: shares are against every enchantment of the stack, not only those the
-        // layers name.
-        let levels = enchantments.iter().map(|(_, level)| *level as f32);
-        let total = match global.method {
-            Method::Average => levels.sum::<f32>(),
-            Method::Layered => levels.fold(0.0, f32::max),
-            Method::None | Method::Cycle => 0.0,
-        };
-        let shared = matches!(global.method, Method::Average | Method::Layered);
-        let layers = layers
-            .into_iter()
-            .map(|i| {
-                let rule = &rules[i];
-                let named = &rule.enchantments;
-                let weight = if !shared || named.is_empty() {
-                    1.0
-                } else {
-                    // The highest level among the enchantments the rule names whose level also
-                    // passes its `enchantmentLevels` (CIT Resewn takes the first named one the
-                    // stack has, whatever its level).
-                    let in_range = |level: u32| {
-                        let level = i32::try_from(level).unwrap_or(i32::MAX);
-                        rule.enchantment_levels
-                            .as_ref()
-                            .is_none_or(|r| r.contains(level))
-                    };
-                    let level = enchantments
-                        .iter()
-                        .filter(|(id, level)| {
-                            let id: &str = id.as_ref();
-                            named.iter().any(|n| n == id) && in_range(*level)
-                        })
-                        .map(|(_, level)| *level as f32)
-                        .fold(0.0, f32::max);
-                    if total > 0.0 { level / total } else { 0.0 }
-                };
-                GlintLayer {
-                    rule: i,
-                    weight,
-                    duration: rule.glint.duration,
-                }
-            })
-            .collect();
+    /// `layers`, bottom first; `vanilla` whether vanilla's glint draws under them; `cycle_fade`
+    /// the seconds each layer fades into the next when they take turns, else `None` (each
+    /// draws at its weight).
+    pub fn from_parts(layers: Vec<GlintLayer>, vanilla: bool, cycle_fade: Option<f32>) -> Self {
         Self {
             layers,
             vanilla,
-            cycle_fade: cycle.then_some(global.fade),
+            cycle_fade,
         }
     }
 
@@ -179,208 +100,3 @@ fn cycle_intensity(layers: &[GlintLayer], fade: f32, index: usize, seconds: f64)
     // Not reached, as the last layer returns above; no layer rather than a panic.
     0.0
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use horizon_optifine::Properties;
-
-    const DIR: &str = "assets/minecraft/optifine/cit";
-
-    /// An enchantment rule named `name` with `text` after `type` and `texture`.
-    fn rule(name: &str, text: &str) -> Rule {
-        let text = format!("type=enchantment\ntexture=glint\n{text}");
-        let path = format!("{DIR}/{name}.properties");
-        Rule::parse(&path, &Properties::parse_equals_first(&text), |_| true).unwrap()
-    }
-
-    fn global(text: &str) -> Global {
-        Global::parse(&Properties::parse_equals_first(text))
-    }
-
-    fn rules_of(layers: &StackGlint) -> Vec<usize> {
-        layers.layers.iter().map(|l| l.rule).collect()
-    }
-
-    const SWORD: [(&str, u32); 2] = [("minecraft:sharpness", 3), ("minecraft:unbreaking", 1)];
-
-    #[test]
-    fn one_rule_per_layer_bottom_first() {
-        let rules = [
-            rule("a", "layer=2"),
-            rule("b", "layer=0"),
-            rule("c", "layer=2"),
-            rule("d", "layer=-1"),
-        ];
-        // Priority order a, b, c, d: c loses layer 2 to a.
-        let g = StackGlint::new(&rules, &[0, 1, 2, 3], &SWORD, &Global::default());
-        assert_eq!(rules_of(&g), [3, 1, 0]);
-        let g = StackGlint::new(&rules, &[2, 0], &SWORD, &Global::default());
-        assert_eq!(rules_of(&g), [2]);
-    }
-
-    #[test]
-    fn average_and_layered_shares() {
-        let rules = [
-            rule("sharp", "enchantments=sharpness smite"),
-            rule("unb", "layer=1\nenchantments=unbreaking"),
-            rule("any", "layer=2"),
-            rule("fire", "layer=3\nenchantments=fire_aspect"),
-        ];
-        let weights = |method: &str| {
-            let g = StackGlint::new(&rules, &[0, 1, 2, 3], &SWORD, &global(method));
-            g.layers.iter().map(|l| l.weight).collect::<Vec<_>>()
-        };
-        // Sharpness III and Unbreaking I: 3 / 4 and 1 / 4; against the highest, 3 / 3 and 1 / 3.
-        // A rule naming no enchantment is at full strength, one the stack lacks at none.
-        assert_eq!(weights("method=average"), [0.75, 0.25, 1.0, 0.0]);
-        assert_eq!(weights("method=layered"), [1.0, 1.0 / 3.0, 1.0, 0.0]);
-        assert_eq!(weights("method=cycle"), [1.0; 4]);
-        assert_eq!(weights("method=none"), [1.0; 4]);
-    }
-
-    #[test]
-    fn the_level_is_one_the_rules_levels_allow() {
-        let rules = [rule(
-            "holy",
-            "enchantments=sharpness smite\nenchantmentLevels=1-2",
-        )];
-        // Sharpness V is out of range, so Smite I sets the share: 1 / 5 of the highest level.
-        let stack = [("minecraft:sharpness", 5), ("minecraft:smite", 1)];
-        let g = StackGlint::new(&rules, &[0], &stack, &global("method=layered"));
-        assert_eq!(g.layers[0].weight, 1.0 / 5.0);
-    }
-
-    #[test]
-    fn cap_keeps_the_topmost_layers() {
-        let rules = [
-            rule("a", "layer=0"),
-            rule("b", "layer=1"),
-            rule("c", "layer=2"),
-        ];
-        let g = StackGlint::new(&rules, &[0, 1, 2], &SWORD, &global("cap=2"));
-        assert_eq!(rules_of(&g), [1, 2]);
-        let g = StackGlint::new(&rules, &[0, 1, 2], &SWORD, &global("cap=0"));
-        assert!(g.is_empty());
-        let g = StackGlint::new(&rules, &[0, 1, 2], &SWORD, &global("cap=1\nmethod=none"));
-        assert_eq!(rules_of(&g), [2]);
-        // Cycles show every layer in turn.
-        let g = StackGlint::new(&rules, &[0, 1, 2], &SWORD, &global("cap=1\nmethod=cycle"));
-        assert_eq!(rules_of(&g), [0, 1, 2]);
-    }
-
-    #[test]
-    fn vanilla_glint() {
-        let plain = rule("plain", "");
-        let keep = rule("keep", "layer=1\nuseGlint=true");
-        let rules = [plain, keep];
-        let vanilla = |matched: &[usize], text: &str| {
-            StackGlint::new(&rules, matched, &SWORD, &global(text)).vanilla
-        };
-        assert!(vanilla(&[], ""), "no rule: vanilla's glint");
-        assert!(!vanilla(&[0], ""), "a rule replaces it");
-        assert!(vanilla(&[0, 1], ""), "unless one keeps it");
-        assert!(!vanilla(&[], "useGlint=false"));
-        assert!(!vanilla(&[1], "useGlint=false"), "the pack's word is final");
-        // Only the layers `cap` keeps count.
-        let rules = [rule("keep", "useGlint=true"), rule("top", "layer=1")];
-        let g = StackGlint::new(&rules, &[0, 1], &SWORD, &global("cap=1"));
-        assert!(!g.vanilla);
-        let g = StackGlint::new(&rules, &[0, 1], &SWORD, &global("cap=0"));
-        assert!(g.is_empty() && g.vanilla);
-        let g = StackGlint::new(&rules, &[0, 1], &SWORD, &global("cap=0\nuseGlint=false"));
-        assert!(!g.vanilla);
-    }
-
-    #[test]
-    fn cycles_take_turns_and_fade() {
-        let rules = [
-            rule("a", "duration=2"),
-            rule("b", "layer=1\nduration=1"),
-            rule("c", "layer=2\nduration=1"),
-        ];
-        let g = StackGlint::new(
-            &rules,
-            &[0, 1, 2],
-            &SWORD,
-            &global("method=cycle\nfade=0.5"),
-        );
-        // a 0-2, a→b 2-2.5, b 2.5-3.5, b→c 3.5-4, c 4-5, c→a 5-5.5, then again.
-        let at = |t: f64| [0, 1, 2].map(|i| g.intensity(i, t));
-        assert_eq!(at(1.0), [1.0, 0.0, 0.0]);
-        assert_eq!(at(2.125), [0.75, 0.25, 0.0]);
-        assert_eq!(at(3.0), [0.0, 1.0, 0.0]);
-        assert_eq!(at(3.75), [0.0, 0.5, 0.5]);
-        assert_eq!(at(4.5), [0.0, 0.0, 1.0]);
-        assert_eq!(at(5.25), [0.5, 0.0, 0.5]);
-        assert_eq!(at(5.5 + 3.0), [0.0, 1.0, 0.0]);
-        // One layer always shows.
-        let one = StackGlint::new(&rules, &[1], &SWORD, &global("method=cycle"));
-        assert_eq!(one.intensity(0, 0.7), 1.0);
-    }
-
-    #[test]
-    fn a_cycle_always_shows_a_whole_layer() {
-        let rules = [
-            rule("a", "duration=0.1"),
-            rule("b", "layer=1\nduration=0.7"),
-            rule("c", "layer=2\nduration=0.2"),
-        ];
-        let g = StackGlint::new(
-            &rules,
-            &[0, 1, 2],
-            &SWORD,
-            &global("method=cycle\nfade=0.3"),
-        );
-        // Every millisecond of the first two seconds, and just under a period, the last fade's
-        // end. (Rounding has not been seen to leave time past it; the last fade's clamp is
-        // defensive.)
-        let period: f64 = [0.1f32, 0.7, 0.2]
-            .map(|d| f64::from(d) + f64::from(0.3f32))
-            .iter()
-            .sum();
-        let last = f64::from_bits(period.to_bits() - 1);
-        for t in (0..2000_i32)
-            .map(|i| f64::from(i) * 0.001)
-            .chain([last, period + last])
-        {
-            let sum: f32 = (0..3).map(|i| g.intensity(i, t)).sum();
-            assert!((sum - 1.0).abs() < 1e-5, "{sum} at {t}");
-        }
-        // No time at all: the bottom layer alone, never NaN.
-        let still = [rule("a", "duration=0"), rule("b", "layer=1\nduration=0")];
-        let g = StackGlint::new(&still, &[0, 1], &SWORD, &global("method=cycle\nfade=0"));
-        for t in [0.0, 0.5, 7.25] {
-            assert_eq!([0, 1].map(|i| g.intensity(i, t)), [1.0, 0.0]);
-        }
-    }
-
-    #[test]
-    fn the_first_global_file_wins() {
-        let root = std::env::temp_dir().join(format!("horizon-cit-glint-{}", std::process::id()));
-        let _ = std::fs::remove_dir_all(&root);
-        assert_eq!(load_global(&root), Global::default());
-        let write = |path: &str, text: &[u8]| {
-            let file = root.join(path);
-            std::fs::create_dir_all(file.parent().unwrap()).unwrap();
-            std::fs::write(file, text).unwrap();
-        };
-        // Saved as Latin-1 (`é` is not UTF-8 alone), in the OptiFine doc's `cit/` folder.
-        write(
-            "assets/minecraft/optifine/cit/cit.properties",
-            b"# caf\xE9\nmethod=cycle",
-        );
-        assert_eq!(load_global(&root).method, Method::Cycle);
-        write("assets/minecraft/mcpatcher/cit.properties", b"method=none");
-        assert_eq!(load_global(&root).method, Method::Cycle);
-        write(
-            "assets/minecraft/optifine/cit.properties",
-            b"method=layered",
-        );
-        assert_eq!(load_global(&root).method, Method::Layered);
-        write("assets/minecraft/citresewn/cit.properties", b"cap=1");
-        let g = load_global(&root);
-        let _ = std::fs::remove_dir_all(&root);
-        assert_eq!((g.method, g.cap), (Method::Average, Some(1)));
-    }
-}

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

@@ -0,0 +1,271 @@
+//! Entity textures a pack format vanilla doesn't read changes (OptiFine's random entities, ETF's
+//! blinking and emissive textures): the variants of each texture and how an entity picks one,
+//! the blink frames a texture shows now and then, and the overlays that glow over a texture.
+//! The platform's pack formats fill them once per pack load ([`crate::pack_hooks`]); drawing
+//! only looks them up in these tables.
+//!
+//! Textures have the names the entity atlas gives them (`entity/zombie/zombie`,
+//! `<ns>:<path>`); files outside `textures/` are listed with the name they take
+//! ([`RandomTextures::files`], [`Blinks::files`], [`Emissive::files`]) for the atlas to pack.
+
+use std::collections::{BTreeMap, HashMap};
+use std::path::Path;
+
+/// A pack's entity texture changes: variants, blinks and emissive overlays.
+#[derive(Debug, Default)]
+pub struct EntityTextures {
+    pub random: RandomTextures,
+    pub blinks: Blinks,
+    pub emissive: Emissive,
+}
+
+impl EntityTextures {
+    /// The changes of the overlay at `root`, from the installed pack formats.
+    pub fn load(root: &Path) -> Self {
+        crate::pack_hooks::formats()
+            .entity_textures(root)
+            .unwrap_or_default()
+    }
+}
+
+/// What a variant rule can ask about an entity. `None` is a fact the entity doesn't have (a
+/// creeper's profession): a rule asking for it doesn't match.
+#[derive(Clone, Debug, Default)]
+pub struct Facts<'a> {
+    /// Where the entity was first seen: its biome (`minecraft:plains`) and block height.
+    pub biome: Option<&'a str>,
+    pub y: Option<i32>,
+    /// The block it stood on and the block it stood in when first seen; empty when unknown.
+    pub blocks: &'a [Block<'a>],
+    /// Its custom name, with `§` formatting codes where the name has them.
+    pub name: Option<&'a str>,
+    /// Villager profession (`minecraft:farmer`) and level.
+    pub profession: Option<(&'a str, i32)>,
+    /// Collar, wool, carpet or shell colour, as a dye name (`light_blue`).
+    pub color: Option<&'a str>,
+    pub baby: Option<bool>,
+    /// Health and max health.
+    pub health: Option<(f32, f32)>,
+    /// When first seen: moon phase (0-7), time of day (0-23999) and weather.
+    pub moon_phase: Option<i32>,
+    pub day_time: Option<i32>,
+    pub weather: Option<Weather>,
+    /// Slime, magma cube or phantom size: 0 small, 1 medium, 3 big.
+    pub size: Option<i32>,
+}
+
+/// A block and the values of its state properties.
+#[derive(Clone, Copy, Debug)]
+pub struct Block<'a> {
+    pub id: &'a str,
+    pub states: &'a [(&'a str, &'a str)],
+}
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum Weather {
+    Clear,
+    Rain,
+    Thunder,
+}
+
+/// How a pack format's rule files choose a variant.
+pub trait VariantRules: Send + Sync {
+    /// The variant rule file `rules` ([`Entry::rules`]) gives an entity with these facts and
+    /// seed, `None` when no rule matches.
+    fn matching(&self, rules: usize, facts: &Facts, seed: i32) -> Option<u32>;
+}
+
+/// Every texture a pack varies, by its atlas name.
+#[derive(Default)]
+pub struct RandomTextures {
+    entries: HashMap<String, Entry>,
+    /// Every variant's file (from the resource root) and atlas name.
+    files: Vec<(String, String)>,
+    rules: Option<Box<dyn VariantRules>>,
+    generation: u64,
+}
+
+impl std::fmt::Debug for RandomTextures {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("RandomTextures")
+            .field("entries", &self.entries)
+            .field("generation", &self.generation)
+            .finish_non_exhaustive()
+    }
+}
+
+/// One texture's variants.
+#[derive(Clone, Debug, Default, PartialEq)]
+pub struct Entry {
+    /// The rule file that chooses this texture's variant ([`RandomTextures::matching`]).
+    pub rules: Option<usize>,
+    /// The atlas name of each variant, by its number.
+    pub variants: BTreeMap<u32, String>,
+}
+
+impl RandomTextures {
+    /// `entries` by atlas name, their variants' `files` (file, atlas name), the rule files
+    /// `rules` that choose, and `generation`: different for every load (never 0), so choices
+    /// made from another load's rules are known to be stale.
+    pub fn new(
+        entries: HashMap<String, Entry>,
+        files: Vec<(String, String)>,
+        rules: Box<dyn VariantRules>,
+        generation: u64,
+    ) -> Self {
+        Self {
+            entries,
+            files,
+            rules: Some(rules),
+            generation,
+        }
+    }
+
+    /// This load's number; 0 for the empty set.
+    pub fn generation(&self) -> u64 {
+        self.generation
+    }
+
+    pub fn is_empty(&self) -> bool {
+        self.entries.is_empty()
+    }
+
+    /// The variants of the texture with this atlas name.
+    pub fn get(&self, texture: &str) -> Option<&Entry> {
+        self.entries.get(texture)
+    }
+
+    /// [`VariantRules::matching`].
+    pub fn matching(&self, rules: usize, facts: &Facts, seed: i32) -> Option<u32> {
+        self.rules.as_ref()?.matching(rules, facts, seed)
+    }
+
+    /// Every variant's file (its path from the resource root) and atlas name, for the entity
+    /// atlas to pack.
+    pub fn files(&self) -> impl Iterator<Item = (&str, &str)> {
+        self.files.iter().map(|(f, n)| (f.as_str(), n.as_str()))
+    }
+}
+
+impl Entry {
+    /// The atlas name of variant `index`, or `None` for the texture itself.
+    pub fn texture(&self, index: u32) -> Option<&str> {
+        self.variants.get(&index).map(String::as_str)
+    }
+
+    /// The even choice of an entity with this seed when no rules apply: the texture and its
+    /// variants 2, 3... up to the first missing one.
+    pub fn even(&self, seed: i32) -> u32 {
+        let mut count = 1;
+        while self.variants.contains_key(&(count + 1)) {
+            count += 1;
+        }
+        seed.unsigned_abs() % count + 1
+    }
+}
+
+/// An entity's seed from its UUID (most then least significant 64 bits): Java's
+/// `UUID.hashCode`, so it is fixed for the entity's whole life, on every client.
+pub fn seed(most: i64, least: i64) -> i32 {
+    let x = most ^ least;
+    ((x >> 32) ^ x) as i32
+}
+
+/// The pack's blinking textures, by the atlas name of the texture they replace.
+#[derive(Debug, Default)]
+pub struct Blinks {
+    blinks: HashMap<String, Blink>,
+    /// The blink frames outside `textures/`: file and atlas name.
+    files: Vec<(String, String)>,
+}
+
+/// A texture's blink.
+#[derive(Clone, Debug, PartialEq)]
+pub struct Blink {
+    /// The atlas names of the shut and half-shut frames.
+    pub shut: String,
+    pub half: Option<String>,
+    /// Ticks a blink lasts (at least 1) and ticks from one blink to the next (more).
+    pub length: u32,
+    pub frequency: u32,
+}
+
+impl Blinks {
+    /// `blinks` by the atlas name of the texture they replace, and the frames outside
+    /// `textures/` (file, atlas name).
+    pub fn new(blinks: HashMap<String, Blink>, files: Vec<(String, String)>) -> Self {
+        Self { blinks, files }
+    }
+
+    pub fn is_empty(&self) -> bool {
+        self.blinks.is_empty()
+    }
+
+    pub fn get(&self, texture: &str) -> Option<&Blink> {
+        self.blinks.get(texture)
+    }
+
+    /// The frames outside `textures/`: file and atlas name, for the entity atlas to pack (it
+    /// walks `textures/` itself).
+    pub fn files(&self) -> impl Iterator<Item = (&str, &str)> {
+        self.files.iter().map(|(f, n)| (f.as_str(), n.as_str()))
+    }
+}
+
+impl Blink {
+    /// The frame an entity shows `tick` ticks into its life: `None` with its eyes open. `phase`
+    /// spreads entities' blinks apart. With a half-shut frame, the first and last ticks of a
+    /// blink of 3 or more show it.
+    pub fn frame(&self, tick: u32, phase: u32) -> Option<&str> {
+        let t = (u64::from(tick) + u64::from(phase)) % u64::from(self.frequency);
+        let t = t as u32;
+        if t >= self.length {
+            return None;
+        }
+        match &self.half {
+            Some(half) if self.length >= 3 && (t == 0 || t == self.length - 1) => Some(half),
+            _ => Some(&self.shut),
+        }
+    }
+}
+
+/// The pack's emissive overlays, by the atlas name of the texture they glow over.
+#[derive(Debug, Default)]
+pub struct Emissive {
+    /// The name ending of the pack's emissive textures (`_e`).
+    pub suffix: String,
+    overlays: HashMap<String, String>,
+    /// Overlays outside `textures/`: file and atlas name.
+    files: Vec<(String, String)>,
+}
+
+impl Emissive {
+    /// `overlays` (texture → overlay, atlas names) with name ending `suffix`, and those outside
+    /// `textures/` (file, atlas name).
+    pub fn new(
+        suffix: String,
+        overlays: HashMap<String, String>,
+        files: Vec<(String, String)>,
+    ) -> Self {
+        Self {
+            suffix,
+            overlays,
+            files,
+        }
+    }
+
+    pub fn is_empty(&self) -> bool {
+        self.overlays.is_empty()
+    }
+
+    /// The atlas name of the overlay that glows over `texture`.
+    pub fn overlay(&self, texture: &str) -> Option<&str> {
+        self.overlays.get(texture).map(String::as_str)
+    }
+
+    /// The overlays outside `textures/`: file (from the resource root) and atlas name, for the
+    /// entity atlas to pack (it walks `textures/` itself).
+    pub fn files(&self) -> impl Iterator<Item = (&str, &str)> {
+        self.files.iter().map(|(f, n)| (f.as_str(), n.as_str()))
+    }
+}

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

@@ -265,7 +265,7 @@ impl horizon_polytone::expr::Host for FrameHost<'_> {
             ("config", [horizon_polytone::expr::Value::Str(id)]) => self
                 .configs
                 .get(id)
-                .map(horizon_polytone::pack::ConfigValue::to_value)
+                .map(horizon_polytone::pack::config_value)
                 .ok_or_else(|| format!("no config {id}")),
             _ => Err(format!(
                 "{name} is not available in an attribute expression"
@@ -1103,6 +1103,7 @@ mod tests {
         for (path, text) in pack {
             write(&format!("pack/{path}"), text);
         }
+        crate::pack_formats::install();
         let modifiers = PackModifiers::read(&dir.join("pack")).with_configs(
             crate::packs::polytone_configs(&crate::packs::Source::Dir(dir.join("pack"))),
         );

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

@@ -1001,12 +1001,14 @@ impl Hdr {
     }
 }
 
-/// Horizon's icon (horizon-theme) as a 1-bit mask: its white strokes, one colour with hard
-/// edges, are the logo; everything else is not.
+/// The windows' icon (`window::set_icon_png`: Horizon's in the official game) as a 1-bit mask:
+/// its white strokes, one colour with hard edges, are the logo; everything else is not. No icon
+/// given: an empty mask.
 fn logo_mask(device: &wgpu::Device, queue: &wgpu::Queue) -> wgpu::TextureView {
     use wgpu::util::DeviceExt;
-    let (w, h, rgba) =
-        crate::hud::decode_bytes(horizon_theme::ICON_PNG).unwrap_or((1, 1, vec![0; 4]));
+    let (w, h, rgba) = horizon_client_input::window::icon_png()
+        .and_then(|png| crate::hud::decode_bytes(png).ok())
+        .unwrap_or((1, 1, vec![0; 4]));
     let mask: Vec<u8> = rgba
         .as_chunks::<4>()
         .0

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

@@ -2,16 +2,21 @@
 //! colours and the controls it draws with. The screen (`graphics_ui`) only
 //! lays out rows and handles input; a menu theme replaces this module.
 //!
-//! It takes the design system's Blocks palette (`horizon_theme::BLOCKS_DARK`,
-//! `docs/design-system.md`) in a lighter form: square panels of dark glass
-//! with a thin edge, so the world shows through, flat controls, and the violet
-//! face on the one main button, in vanilla's font.
+//! Its colours come from `menu_style`, given at startup (in the official game the design
+//! system's Blocks palette, `docs/design-system.md`), in a lighter form: square panels of
+//! dark glass with a thin edge, so the world shows through, flat controls, and the face on
+//! the one main button, in vanilla's font.
+use crate::menu_style::{self, SettingsColours};
 use crate::{
     hud::{HudAtlas, HudBatch},
     text::Text,
     ui,
 };
-use horizon_theme::BLOCKS_DARK as B;
+
+/// The settings pages' colours (`menu_style`, given at startup).
+fn b() -> &'static SettingsColours {
+    &menu_style::get().settings
+}
 
 /// What a setting costs in frame time, shown with its description.
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
@@ -36,54 +41,91 @@ impl Cost {
     /// `0xRRGGBB`: the palette's success, warn and danger.
     pub fn rgb(self) -> u32 {
         match self {
-            Cost::None => B.ink_soft,
-            Cost::Low | Cost::Saves => B.success,
-            Cost::Medium => B.warn,
-            Cost::High => B.danger,
+            Cost::None => b().ink_soft,
+            Cost::Low | Cost::Saves => b().success,
+            Cost::Medium => b().warn,
+            Cost::High => b().danger,
         }
     }
 }
 
-/// `0xRRGGBB` and an alpha in the HUD's colour encoding.
-const fn hex(c: u32, a: u8) -> u32 {
-    (a as u32) << 24 | (c & 0xff) << 16 | (c >> 8 & 0xff) << 8 | (c >> 16 & 0xff)
-}
+use menu_style::hud_colour as hex;
 /// The plate and the strip: the page's dark, see-through, so the world shows behind them.
-const GLASS: u32 = hex(B.page, 118);
+fn glass() -> u32 {
+    hex(b().page, 118)
+}
 /// Their 1 px edge.
-const EDGE: u32 = hex(B.ink, 26);
+pub fn edge() -> u32 {
+    hex(b().ink, 26)
+}
 /// A group's panel, a little lighter than the plate it sits on.
-const GROUP: u32 = hex(B.ink, 11);
+fn group_fill() -> u32 {
+    hex(b().ink, 11)
+}
 /// A hovered or focused row, lit on its group's panel.
-pub const HOVER: u32 = hex(B.ink, 18);
+pub fn hover() -> u32 {
+    hex(b().ink, 18)
+}
 /// The open page in the page list.
-pub const OPEN: u32 = hex(B.ink, 26);
+pub fn open() -> u32 {
+    hex(b().ink, 26)
+}
 /// The rule under the plate's heading, and between two rows of a group.
-pub const HEAD_RULE: u32 = hex(B.ink, 31);
-pub const ROW_RULE: u32 = hex(B.ink, 15);
+pub fn head_rule() -> u32 {
+    hex(b().ink, 31)
+}
+pub fn row_rule() -> u32 {
+    hex(b().ink, 15)
+}
 /// Fields, boxes and the value stepper: sunk, see-through.
-const WELL: u32 = hex(B.outline, 102);
+fn well_fill() -> u32 {
+    hex(b().outline, 102)
+}
 /// A button, a slider's track, the scroller's thumb.
-const BUTTON: u32 = hex(B.ink, 20);
-const BUTTON_HOVER: u32 = hex(B.ink, 41);
-const TRACK: u32 = hex(B.ink, 64);
-const HANDLE: u32 = hex(B.ink, 255);
+fn button_fill() -> u32 {
+    hex(b().ink, 20)
+}
+fn button_hover() -> u32 {
+    hex(b().ink, 41)
+}
+fn track_fill() -> u32 {
+    hex(b().ink, 64)
+}
+fn handle_fill() -> u32 {
+    hex(b().ink, 255)
+}
 /// The one main button.
-const FACE: u32 = hex(B.face, 255);
-const FACE_HOVER: u32 = hex(0x6a50e6, 255);
+pub fn face() -> u32 {
+    hex(b().face, 255)
+}
+fn face_hover() -> u32 {
+    hex(b().face_hover, 255)
+}
 /// A tick box's edge when off.
-const BOX_EDGE: u32 = hex(B.ink_soft, 89);
-const OUTLINE: u32 = hex(B.outline, 255);
-pub const ACCENT: u32 = hex(B.accent, 255);
+fn box_edge() -> u32 {
+    hex(b().ink_soft, 89)
+}
+fn outline() -> u32 {
+    hex(b().outline, 255)
+}
+pub fn accent() -> u32 {
+    hex(b().accent, 255)
+}
 /// Vanilla's white text, and its grey for what can't be used now.
 pub const WHITE: u32 = u32::MAX;
-pub const MUTED: u32 = hex(B.muted, 255);
+pub fn muted() -> u32 {
+    hex(b().muted, 255)
+}
 /// A page that isn't open, a value at rest.
-pub const SOFT: u32 = hex(B.ink_soft, 255);
+pub fn soft() -> u32 {
+    hex(b().ink_soft, 255)
+}
 /// Vanilla's grey for a tooltip's lines under its first (`ChatFormatting.GRAY`).
 pub const GREY: u32 = hex(0xaaaaaa, 255);
 /// A light veil over the backdrop, under the panels.
-pub const VEIL: u32 = hex(B.page, 77);
+pub fn veil() -> u32 {
+    hex(b().page, 77)
+}
 
 /// Sizes in GUI pixels.
 /// Shorter screens than this (a 720p window at scale 3) keep a narrower margin on top.
@@ -120,21 +162,21 @@ pub fn ring(batch: &mut HudBatch, atlas: &HudAtlas, [x, y, w, h]: [f32; 4], colo
 }
 /// The screen's plate, and the strip under it: dark glass with a thin edge.
 pub fn panel(batch: &mut HudBatch, atlas: &HudAtlas, rect: [f32; 4]) {
-    fill(batch, atlas, rect, GLASS);
-    ring(batch, atlas, rect, EDGE);
+    fill(batch, atlas, rect, glass());
+    ring(batch, atlas, rect, edge());
 }
 /// A group's panel on the plate, its rows on it.
 pub fn group(batch: &mut HudBatch, atlas: &HudAtlas, rect: [f32; 4]) {
-    fill(batch, atlas, rect, GROUP);
+    fill(batch, atlas, rect, group_fill());
 }
 /// A sunk well: the search field, the value stepper.
 pub fn well(batch: &mut HudBatch, atlas: &HudAtlas, rect: [f32; 4]) {
-    fill(batch, atlas, rect, WELL);
+    fill(batch, atlas, rect, well_fill());
 }
 /// The scroller: a faint track and its thumb.
 pub fn scroller(batch: &mut HudBatch, atlas: &HudAtlas, track: [f32; 4], thumb: [f32; 4]) {
-    fill(batch, atlas, track, ROW_RULE);
-    fill(batch, atlas, thumb, TRACK);
+    fill(batch, atlas, track, row_rule());
+    fill(batch, atlas, thumb, track_fill());
 }
 /// `text` cut to `width` with an ellipsis, as a long name gives way to its control: the HUD
 /// kit's `fit::ellipsize`.
@@ -142,11 +184,11 @@ pub use crate::hud_kit::fit::ellipsize as fit;
 /// A 12 px tick box ending at `right`, centred in the row at `y`: its edge in the accent when on.
 pub fn checkbox(batch: &mut HudBatch, atlas: &HudAtlas, right: f32, y: f32, on: bool, live: bool) {
     let rect = [right - 12.0, y + 4.0, 12.0, 12.0];
-    fill(batch, atlas, rect, WELL);
+    fill(batch, atlas, rect, well_fill());
     let edge = match (on, live) {
-        (true, true) => ACCENT,
-        (true, false) => MUTED,
-        (false, _) => BOX_EDGE,
+        (true, true) => accent(),
+        (true, false) => muted(),
+        (false, _) => box_edge(),
     };
     ring(batch, atlas, rect, edge);
     if on {
@@ -169,7 +211,7 @@ fn tick(batch: &mut HudBatch, atlas: &HudAtlas, x: f32, y: f32, color: u32) {
         for (i, c) in row.chars().enumerate() {
             if c == '#' {
                 let (px, py) = (x + i as f32, y + j as f32);
-                fill(batch, atlas, [px + 1.0, py + 1.0, 1.0, 1.0], OUTLINE);
+                fill(batch, atlas, [px + 1.0, py + 1.0, 1.0, 1.0], outline());
                 fill(batch, atlas, [px, py, 1.0, 1.0], color);
             }
         }
@@ -198,17 +240,17 @@ pub fn button_with_room(
 ) {
     let [x, y, w, h] = rect;
     let face = match (live, primary, hover) {
-        (false, _, _) => WELL,
-        (true, true, false) => FACE,
-        (true, true, true) => FACE_HOVER,
-        (true, false, false) => BUTTON,
-        (true, false, true) => BUTTON_HOVER,
+        (false, _, _) => well_fill(),
+        (true, true, false) => face(),
+        (true, true, true) => face_hover(),
+        (true, false, false) => button_fill(),
+        (true, false, true) => button_hover(),
     };
     fill(batch, atlas, rect, face);
     if hover && live {
         ring(batch, atlas, rect, WHITE);
     }
-    let color = if live { WHITE } else { MUTED };
+    let color = if live { WHITE } else { muted() };
     let ty = y + ((h - 8.0) / 2.0).floor();
     let left = x + 2.0 + room;
     scrolling_label(
@@ -252,7 +294,7 @@ pub fn slider(
     (hover, live): (bool, bool),
 ) {
     let [x, y, w, h] = rect;
-    let color = if live { WHITE } else { MUTED };
+    let color = if live { WHITE } else { muted() };
     scrolling_label(
         batch,
         atlas,
@@ -263,17 +305,22 @@ pub fn slider(
     );
     let line = y + h - 3.0;
     let at = x + (position.clamp(0.0, 1.0) * (w - 4.0)).round();
-    fill(batch, atlas, [x, line, w, 2.0], TRACK);
+    fill(batch, atlas, [x, line, w, 2.0], track_fill());
     fill(
         batch,
         atlas,
         [x, line, at - x, 2.0],
-        if live { ACCENT } else { MUTED },
+        if live { accent() } else { muted() },
     );
     let handle = [at, line - 3.0, 4.0, 8.0];
-    fill(batch, atlas, handle, if live { HANDLE } else { MUTED });
+    fill(
+        batch,
+        atlas,
+        handle,
+        if live { handle_fill() } else { muted() },
+    );
     if hover && live {
-        ring(batch, atlas, [at - 1.0, line - 4.0, 6.0, 10.0], ACCENT);
+        ring(batch, atlas, [at - 1.0, line - 4.0, 6.0, 10.0], accent());
     }
 }
 /// A value that a press steps through: in a well, between the arrows that say so.
@@ -290,13 +337,13 @@ pub fn cycler(
         ring(batch, atlas, rect, WHITE);
     }
     let ty = y + ((h - 8.0) / 2.0).floor();
-    let arrows = if hover && live { WHITE } else { MUTED };
+    let arrows = if hover && live { WHITE } else { muted() };
     batch.text_styled(atlas, &Text::literal("<"), x + 3.0, ty, arrows, true);
     batch.text_styled(atlas, &Text::literal(">"), x + w - 8.0, ty, arrows, true);
     let color = match (live, hover) {
-        (false, _) => MUTED,
+        (false, _) => muted(),
         (true, true) => WHITE,
-        (true, false) => SOFT,
+        (true, false) => soft(),
     };
     scrolling_label(batch, atlas, value, [x + 9.0, ty, w - 18.0], (y, h), color);
 }

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

@@ -111,11 +111,11 @@ pub struct HudAtlas {
     /// The packs' Polytone screen sprite modifiers.
     pub sprite_modifiers: std::sync::Arc<sprite_modifiers::SpriteModifiers>,
     /// The packs' OptiFine random entity textures, whose variants this atlas packs.
-    pub random_textures: horizon_optifine::random_textures::RandomTextures,
+    pub random_textures: crate::entity_textures::RandomTextures,
     /// Their emissive overlays (`_e`), packed here too.
-    pub emissive: std::sync::Arc<horizon_optifine::emissive::Emissive>,
+    pub emissive: std::sync::Arc<crate::entity_textures::Emissive>,
     /// ETF's blinking frames (`_blink`), packed here too.
-    pub blinks: horizon_optifine::blink::Blinks,
+    pub blinks: crate::entity_textures::Blinks,
     /// Of the shared atlas's textures, their LabPBR normal and specular maps as paged maps
     /// (`paged_maps.rs`), read while loading for shader packs (`sprites::labpbr_maps`).
     pub material_maps: std::sync::Arc<[Option<crate::paged_maps::PagedMap>; 2]>,
@@ -433,7 +433,7 @@ fn cit_sprites(
     packed: &[PackedImage],
 ) -> Vec<(PackedImage, Option<TextureFlags>, bool)> {
     let have: HashSet<&str> = packed.iter().map(|i| i.0.as_str()).collect();
-    let rules = crate::cit::load_rules(root);
+    let rules = crate::cit::CitRules::load(root).rules;
     let mut ids = crate::cit_assets::item_sprites(&rules);
     if !rules.is_empty() {
         let models = crate::cit_assets::load_models(root, &rules);
@@ -1204,25 +1204,18 @@ impl HudAtlas {
             let s = p.to_string_lossy().replace('\\', "/");
             !s.contains("title/background") && !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)
+        // Random entity variants, under the names their scan gives them (those outside
+        // `textures/` are `<ns>:optifine/random/...`), blink frames and emissive overlays.
+        let crate::entity_textures::EntityTextures {
+            random: random_textures,
+            blinks,
+            emissive,
+        } = if folders.contains(&"entity") {
+            crate::entity_textures::EntityTextures::load(root)
         } else {
             Default::default()
         };
-        let blinks = if folders.contains(&"entity") {
-            horizon_optifine::blink::Blinks::scan(root, &random_textures)
-        } else {
-            Default::default()
-        };
-        let emissive = std::sync::Arc::new(if folders.contains(&"entity") {
-            let mut e = horizon_optifine::emissive::Emissive::scan(root, &random_textures);
-            e.pair_beside(root, blinks.files());
-            e
-        } else {
-            Default::default()
-        });
+        let emissive = std::sync::Arc::new(emissive);
         let mut named: HashMap<PathBuf, String> = HashMap::new();
         let extra = random_textures
             .files()
@@ -3474,6 +3467,7 @@ mod tests {
     /// `RandomTextures` gives them; one beside its texture packs once, under its own.
     #[test]
     fn random_entity_variants_pack_under_their_scan_names() {
+        crate::pack_formats::install();
         let root =
             std::env::temp_dir().join(format!("horizon-atlas-random-{}", std::process::id()));
         let _ = fs::remove_dir_all(&root);
@@ -3496,6 +3490,7 @@ mod tests {
     /// A random variant's emissive overlay packs beside the variant, under its name.
     #[test]
     fn variant_overlays_pack_under_their_names() {
+        crate::pack_formats::install();
         let root =
             std::env::temp_dir().join(format!("horizon-atlas-overlay-{}", std::process::id()));
         let _ = fs::remove_dir_all(&root);
@@ -3810,6 +3805,7 @@ mod tests {
     }
     /// A resource root with one plain item texture and these CIT files (relative path, contents).
     fn cit_root(name: &str, files: &[(&str, &str)]) -> PathBuf {
+        crate::pack_formats::install();
         let root =
             std::env::temp_dir().join(format!("horizon-atlas-cit-{name}-{}", std::process::id()));
         let _ = fs::remove_dir_all(&root);
@@ -3899,7 +3895,7 @@ mod tests {
         );
         let cit = root.join("assets/minecraft/optifine/cit");
         write_strip(&cit.join("a.png"), 64, 32, &[[1, 2, 3, 255]], None);
-        let rules = crate::cit::load_rules(&root);
+        let rules = crate::cit::CitRules::load(&root).rules;
         assert_eq!(rules.len(), 1);
         let atlas = HudAtlas::build(&root).unwrap();
         let _ = fs::remove_dir_all(&root);

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

@@ -1,12 +1,12 @@
-//! OptiFine CIT enchantment glints on GUI items (`type=enchantment`, see `crate::cit_glint` for
+//! Custom item texture enchantment glints on GUI items (`Kind::Enchantment`, see `crate::cit_glint` for
 //! which layers a stack draws): every rule's texture in one texture array, each layer an extra
 //! pass over the item's quads with its rule's blend. A layer's vertices carry its texture slot
 //! (red) and its intensity (alpha) in their colour; its scrolled UV is worked out on the CPU, as
 //! vanilla's glint's is. Without enchantment rules nothing here is made.
 
 use super::HudVertex;
+use crate::cit::{Blend, Factor, Kind, Rule};
 use crate::gfx::hud_coverage::Pipeline;
-use horizon_optifine::cit::{Blend, Factor, Kind, Rule};
 use std::path::Path;
 
 /// Slots the shader's table holds; rules past it draw no layer (and match no stack).
@@ -438,13 +438,11 @@ impl CitGlintPass {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use horizon_optifine::Properties;
-    use horizon_optifine::cit::parse_blend;
+    use crate::pack_formats::cit::{parse_blend, parse_rule};
 
     fn rule(name: &str, text: &str) -> Rule {
         let path = format!("assets/minecraft/optifine/cit/{name}.properties");
-        let text = format!("texture=glint\n{text}");
-        Rule::parse(&path, &Properties::parse_equals_first(&text), |_| true).unwrap()
+        parse_rule(&path, &format!("texture=glint\n{text}")).unwrap()
     }
 
     #[test]

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

@@ -338,7 +338,7 @@ fn coverage_preserves_each_cit_blend_and_its_destination_alpha() {
     let Some(mut gpu) = Gpu::new() else {
         return;
     };
-    use horizon_optifine::cit::parse_blend;
+    use crate::pack_formats::cit::parse_blend;
     for (name, expected) in [
         ("alpha", 128),
         ("add", 0),

crates/horizon-client-render/src/hud_kit/motion.rs

@@ -3,8 +3,9 @@
 //! where a tween is at the frame's [`Clock`]; nothing here holds state or runs on its own, and
 //! no motion ever decides what input does.
 //!
-//! The curves are the design system's (`horizon_theme::QUICK`, `MOVE`): a [`Tween`] takes one
-//! of them, at the theme's duration or a shorter one of its own.
+//! A [`Tween`] takes a duration and a CSS `cubic-bezier` curve: Horizon's overlays use the design
+//! system's (`horizon_theme::QUICK`, `MOVE`), at the theme's duration or a shorter one of their
+//! own.
 //!
 //! The game builds the clock once a frame (`Clock::new(now, still)`). A still clock (the game is
 //! paused, frame-stepped by `HORIZON_STILL` or a screenshot sequence, or a repro recording or
@@ -16,7 +17,7 @@
 //! use std::time::{Duration, Instant};
 //!
 //! let opened = Instant::now();
-//! let open = Tween::new(Duration::from_millis(90), horizon_theme::QUICK);
+//! let open = Tween::new(Duration::from_millis(90), [0.4, 0.0, 0.2, 1.0]);
 //! // Half way through: partly faded in, partly grown from 94%.
 //! let clock = Clock::new(opened + Duration::from_millis(45), false);
 //! let alpha = motion::fade(open, clock, opened);
@@ -26,7 +27,6 @@
 //! let still = Clock::new(opened, true);
 //! assert_eq!(motion::fade(open, still, opened), 1.0);
 //! ```
-use horizon_theme::Motion;
 use std::time::{Duration, Instant};
 
 /// The time a frame shows, built once a frame by the game.
@@ -50,28 +50,20 @@ impl Clock {
     }
 }
 
-/// A duration and one of the design system's easing curves.
+/// A duration and an easing curve.
 #[derive(Clone, Copy, Debug, PartialEq)]
 pub struct Tween {
     /// How long it runs.
     pub duration: Duration,
-    /// The CSS `cubic-bezier` control points of its curve (a `horizon_theme::Motion`'s).
+    /// The CSS `cubic-bezier` control points of its curve.
     pub curve: [f32; 4],
 }
 
 impl Tween {
-    /// `motion`'s curve over `duration`: the dial's motions are shorter than the launcher's, on
-    /// the same curves.
-    pub const fn new(duration: Duration, motion: Motion) -> Self {
-        Self {
-            duration,
-            curve: motion.curve,
-        }
-    }
-
-    /// A theme motion as it is: its own duration and curve.
-    pub const fn of(motion: Motion) -> Self {
-        Self::new(motion.duration(), motion)
+    /// `curve` over `duration`: the dial's motions are shorter than the launcher's, on the same
+    /// curves.
+    pub const fn new(duration: Duration, curve: [f32; 4]) -> Self {
+        Self { duration, curve }
     }
 
     /// The linear progress, 0 to 1, `since` a start at this clock; 1 on a still clock.
@@ -84,7 +76,7 @@ impl Tween {
 
     /// The eased progress, 0 to 1, on the tween's curve.
     pub fn progress(self, clock: Clock, since: Instant) -> f32 {
-        horizon_theme::bezier(self.curve, self.linear(clock, since))
+        bezier(self.curve, self.linear(clock, since))
     }
 
     /// Whether it has finished (always, on a still clock).
@@ -98,6 +90,29 @@ impl Tween {
     }
 }
 
+/// A CSS `cubic-bezier(x1, y1, x2, y2)` at `t` in 0..1: solves x for the curve parameter,
+/// returns y.
+pub fn bezier([x1, y1, x2, y2]: [f32; 4], t: f32) -> f32 {
+    let t = t.clamp(0.0, 1.0);
+    if t == 0.0 || t == 1.0 {
+        return t;
+    }
+    let at = |a: f32, b: f32, s: f32| {
+        let u = 1.0 - s;
+        3.0 * u * u * s * a + 3.0 * u * s * s * b + s * s * s
+    };
+    let (mut lo, mut hi) = (0f32, 1f32);
+    for _ in 0..24 {
+        let mid = (lo + hi) / 2.0;
+        if at(x1, x2, mid) < t {
+            lo = mid;
+        } else {
+            hi = mid;
+        }
+    }
+    at(y1, y2, (lo + hi) / 2.0)
+}
+
 /// An alpha from 0 to 1 as something fades in.
 pub fn fade(tween: Tween, clock: Clock, since: Instant) -> f32 {
     tween.progress(clock, since)
@@ -145,7 +160,7 @@ mod tests {
     #[test]
     fn a_tween_runs_from_its_start_to_its_end_and_holds() {
         let t0 = Instant::now();
-        let tween = Tween::new(MS(80), horizon_theme::MOVE);
+        let tween = Tween::new(MS(80), horizon_theme::MOVE.curve);
         assert_eq!(tween.progress(at(t0, 0), t0), 0.0);
         assert_eq!(tween.progress(at(t0, 80), t0), 1.0);
         assert_eq!(tween.progress(at(t0, 500), t0), 1.0);
@@ -160,8 +175,7 @@ mod tests {
     fn a_still_clock_shows_every_motion_settled() {
         let t0 = Instant::now();
         let still = Clock::new(t0, true);
-        let tween = Tween::of(horizon_theme::QUICK);
-        assert_eq!(tween.duration, horizon_theme::QUICK.duration());
+        let tween = Tween::new(horizon_theme::QUICK.duration(), horizon_theme::QUICK.curve);
         assert_eq!(fade(tween, still, t0), 1.0);
         assert_eq!(fade_out(tween, still, t0), 0.0);
         assert_eq!(scale_in(tween, still, t0, 0.94), 1.0);
@@ -173,7 +187,7 @@ mod tests {
     #[test]
     fn the_helpers_start_where_they_say() {
         let t0 = Instant::now();
-        let tween = Tween::new(MS(100), horizon_theme::QUICK);
+        let tween = Tween::new(MS(100), horizon_theme::QUICK.curve);
         let c = at(t0, 0);
         assert_eq!(fade(tween, c, t0), 0.0);
         assert_eq!(fade_out(tween, c, t0), 1.0);
@@ -184,10 +198,25 @@ mod tests {
         assert!((flash(tween, at(t0, 25), t0) - 0.75).abs() < 1e-6);
     }
 
+    #[test]
+    fn the_curve_is_the_design_systems() {
+        for motion in horizon_theme::MOTION {
+            for i in 0..=20 {
+                let t = i as f32 / 20.0;
+                assert_eq!(
+                    bezier(motion.curve, t),
+                    motion.ease(t),
+                    "{} at {t}",
+                    motion.name
+                );
+            }
+        }
+    }
+
     #[test]
     fn a_turn_takes_the_short_way_round() {
         let t0 = Instant::now();
-        let tween = Tween::new(MS(80), horizon_theme::MOVE);
+        let tween = Tween::new(MS(80), horizon_theme::MOVE.curve);
         // From up-left (7/8 of a turn) to up-right: through up, not round the bottom.
         let from = 7.0 * FRAC_PI_4;
         let half = turn(tween, at(t0, 1), t0, from, FRAC_PI_4);

crates/horizon-client-render/src/hud_kit/tabs.rs

@@ -38,6 +38,12 @@
 //! ```
 use crate::hud::{HudAtlas, HudBatch};
 use crate::hud_kit::{colour, fit};
+use crate::menu_style::{self, OverlayColours};
+
+/// The overlays' colours (`menu_style`, given at startup).
+fn overlay() -> &'static OverlayColours {
+    &menu_style::get().overlay
+}
 
 /// A pip under the strip: its size and the step from one to the next, in GUI px.
 pub const PIP: [f32; 2] = [3.0, 2.0];
@@ -45,8 +51,12 @@ pub const PIP_STEP: f32 = 5.0;
 /// How far, in GUI px, the arrows sit from the name.
 pub const ARROW_GAP: f32 = 4.0;
 /// An arrow with a page that way, and one at an end, with none.
-pub const ARROW: u32 = colour(horizon_theme::BACKDROP_MUTED, 255);
-pub const ARROW_OFF: u32 = colour(horizon_theme::BACKDROP_MUTED, 77);
+pub fn arrow_colour() -> u32 {
+    colour(overlay().backdrop_muted, 255)
+}
+pub fn arrow_off_colour() -> u32 {
+    colour(overlay().backdrop_muted, 77)
+}
 /// The pips (the selected one is white).
 pub const PIP_OFF: u32 = colour(0xFFFFFF, 89);
 pub const PIP_ON: u32 = colour(0xFFFFFF, 255);
@@ -65,9 +75,15 @@ pub const EDGE_FADE: f32 = 12.0;
 pub const FADE: [f32; 5] = [1.0, 0.7, 0.35, 0.15, 0.1];
 /// The selected tab's fill and text, and the others'.
 pub const SELECTED_FILL: u32 = colour(0xFFFFFF, 242);
-pub const SELECTED_TEXT: u32 = colour(horizon_theme::DARK.page, 255);
-pub const TAB_FILL: u32 = colour(horizon_theme::DARK.page, 191);
-pub const TAB_TEXT: u32 = colour(horizon_theme::BACKDROP_MUTED, 255);
+pub fn selected_text() -> u32 {
+    colour(overlay().page, 255)
+}
+pub fn tab_fill() -> u32 {
+    colour(overlay().page, 191)
+}
+pub fn tab_text() -> u32 {
+    colour(overlay().backdrop_muted, 255)
+}
 /// The line of text's height in GUI px (vanilla's font, without its shadow).
 const LINE: f32 = 8.0;
 
@@ -144,7 +160,11 @@ pub fn draw(batch: &mut HudBatch, atlas: &HudAtlas, strip: &Strip) {
             arrow,
             ax,
             ay,
-            if on { ARROW } else { ARROW_OFF },
+            if on {
+                arrow_colour()
+            } else {
+                arrow_off_colour()
+            },
             true,
         );
     }
@@ -282,9 +302,9 @@ pub fn draw_tabs(batch: &mut HudBatch, atlas: &HudAtlas, strip: &TabStrip, alpha
     for tab in &row.tabs {
         let [tx, ty, tw, th] = tab.area;
         let (fill, text) = if tab.selected {
-            (SELECTED_FILL, SELECTED_TEXT)
+            (SELECTED_FILL, selected_text())
         } else {
-            (TAB_FILL, TAB_TEXT)
+            (tab_fill(), tab_text())
         };
         let tab_start = batch.vertices.len();
         // Cut where the edges' fades start, so each fade runs over its own piece.
@@ -380,15 +400,16 @@ mod tests {
             let [ax, _] = strip.arrows[i];
             (batch.vertices.iter())
                 .filter(|v| {
-                    (v.pos[0] - ax).abs() < 4.0 && v.color & 0x00FF_FFFF == ARROW & 0x00FF_FFFF
+                    (v.pos[0] - ax).abs() < 4.0
+                        && v.color & 0x00FF_FFFF == arrow_colour() & 0x00FF_FFFF
                 })
                 .map(|v| v.color >> 24)
                 .max()
                 .unwrap_or(0)
         };
         let first = collapsed(&atlas, &pages, 0, AREA);
-        assert_eq!(alpha(&first, 0), ARROW_OFF >> 24);
-        assert_eq!(alpha(&first, 1), ARROW >> 24);
+        assert_eq!(alpha(&first, 0), arrow_off_colour() >> 24);
+        assert_eq!(alpha(&first, 1), arrow_colour() >> 24);
     }
 
     #[test]

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

@@ -14,7 +14,6 @@ pub mod biome;
 pub mod block_edit;
 pub mod block_entities;
 pub mod block_entity_anim;
-pub mod block_entity_cem;
 pub mod block_entity_render;
 pub mod block_sprites;
 pub mod block_states;
@@ -44,6 +43,7 @@ pub mod custom_sky;
 pub mod datapack;
 pub mod dynamic_light;
 pub mod effects;
+pub mod entity_textures;
 pub mod environment;
 pub mod extras;
 pub(crate) mod extras_ui;
@@ -51,7 +51,6 @@ pub mod fast_hash;
 pub mod fluid_render;
 pub mod fog;
 pub mod font;
-pub mod fusion;
 pub mod gfx;
 pub mod graphics;
 pub mod graphics_style;
@@ -74,6 +73,7 @@ pub mod light;
 pub mod lod;
 pub mod logging;
 pub mod menu_blur;
+pub mod menu_style;
 pub mod mesher;
 pub mod minimap;
 pub mod mipmap;

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

@@ -0,0 +1,145 @@
+//! The look of the screens vanilla doesn't have that the engine still draws: the settings pages
+//! (`graphics_style`), the HUD kit's tab strip, and the overlays drawn with `ui_theme` (the
+//! on-screen keyboard, the boot screen, the missing-resources window). Vanilla's screens never
+//! read it.
+//!
+//! The layer above gives it once at startup ([`install`]), before the first frame; the
+//! official game gives Horizon's design system (`docs/design-system.md`). With none given, the
+//! screens draw in [`NEUTRAL`]: vanilla's greys and chat colours, and no text where they would
+//! use their own fonts. A read is one atomic load, and only those screens make it.
+use std::sync::OnceLock;
+
+/// Colours as `0xRRGGBB`, sizes in dp (the launcher's logical pixels).
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub struct MenuStyle {
+    pub settings: SettingsColours,
+    pub overlay: OverlayColours,
+    pub sizes: Sizes,
+    /// The overlays' TrueType faces; none: they draw no text.
+    pub fonts: Option<Fonts>,
+}
+
+/// The settings pages: square panels of dark glass over the world, flat controls, one face.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub struct SettingsColours {
+    /// The plate behind everything, drawn see-through.
+    pub page: u32,
+    /// Text, and the light the panels, rules, hovers and controls are drawn in.
+    pub ink: u32,
+    /// Secondary text and values.
+    pub ink_soft: u32,
+    /// Labels, descriptions, what can't be used.
+    pub muted: u32,
+    /// Wells and the dark edge of small marks.
+    pub outline: u32,
+    /// Focus, a checked box, a slider's fill.
+    pub accent: u32,
+    /// The one main button, and while hovered.
+    pub face: u32,
+    pub face_hover: u32,
+    pub success: u32,
+    pub warn: u32,
+    pub danger: u32,
+}
+
+/// Overlays drawn over the game (the HUD kit's tab strip, `ui_theme`'s overlays).
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub struct OverlayColours {
+    /// The dark page under text and tabs.
+    pub page: u32,
+    /// Muted text over a veiled backdrop.
+    pub backdrop_muted: u32,
+    /// Text and the light hover and pressed plates are drawn in.
+    pub ink: u32,
+    /// Secondary text and values.
+    pub ink_soft: u32,
+    /// One-pixel rules between rows.
+    pub rule: u32,
+    /// The main action, and its text.
+    pub accent: u32,
+    pub on_accent: u32,
+}
+
+/// `ui_theme`'s type scale and shapes, in dp.
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub struct Sizes {
+    pub caption: f32,
+    pub label: f32,
+    pub ui: f32,
+    pub body: f32,
+    pub title: f32,
+    /// The boot screen's wordmark at its smallest, and its console lines.
+    pub display: f32,
+    pub micro: f32,
+    /// Fields; plates (hover rows, selection); a large control's height.
+    pub radius: f32,
+    pub radius_plate: f32,
+    pub control_large: f32,
+}
+
+/// TrueType faces (`ui_theme::Face`).
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub struct Fonts {
+    pub regular: &'static [u8],
+    pub medium: &'static [u8],
+    pub semibold: &'static [u8],
+    pub mono: &'static [u8],
+}
+
+/// The look with nothing given: vanilla's greys and chat colours.
+pub const NEUTRAL: MenuStyle = MenuStyle {
+    settings: SettingsColours {
+        page: 0x101010,
+        ink: 0xffffff,
+        ink_soft: 0xe0e0e0,
+        muted: 0xa0a0a0,
+        outline: 0x000000,
+        accent: 0xffffff,
+        face: 0x555555,
+        face_hover: 0x6f6f6f,
+        success: 0x55ff55,
+        warn: 0xffff55,
+        danger: 0xff5555,
+    },
+    overlay: OverlayColours {
+        page: 0x101010,
+        backdrop_muted: 0xa0a0a0,
+        ink: 0xffffff,
+        ink_soft: 0xe0e0e0,
+        rule: 0x303030,
+        accent: 0xffffff,
+        on_accent: 0x000000,
+    },
+    sizes: Sizes {
+        caption: 12.0,
+        label: 13.0,
+        ui: 14.0,
+        body: 15.0,
+        title: 28.0,
+        display: 44.0,
+        micro: 11.0,
+        radius: 0.0,
+        radius_plate: 0.0,
+        control_large: 40.0,
+    },
+    fonts: None,
+};
+
+static STYLE: OnceLock<MenuStyle> = OnceLock::new();
+
+/// Give the menus their look: call it once at startup. A second call keeps the first look and
+/// returns false.
+pub fn install(style: MenuStyle) -> bool {
+    STYLE.set(style).is_ok()
+}
+
+/// The look given to [`install`], or [`NEUTRAL`].
+#[inline]
+pub fn get() -> &'static MenuStyle {
+    STYLE.get().unwrap_or(&NEUTRAL)
+}
+
+/// `0xRRGGBB` and an alpha in the HUD's colour encoding (`0xAABBGGRR`).
+pub const fn hud_colour(rgb: u32, alpha: u8) -> u32 {
+    (alpha as u32) << 24 | (rgb & 0xff) << 16 | (rgb >> 8 & 0xff) << 8 | (rgb >> 16 & 0xff)
+}

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

@@ -11,7 +11,7 @@ mod sides;
 #[cfg(test)]
 #[path = "mesher/source_tests.rs"]
 mod source_tests;
-use crate::connected::{Pick, TileLayer};
+use crate::connected::{ConnectedTextures, NoConnected, Pick, TileLayer};
 use crate::{
     assets::{Assets, RenderAssets},
     biome::{Biomes, GrassModifier},
@@ -24,7 +24,6 @@ use horizon_assets::model::Direction as ModelDirection;
 use horizon_core::{
     biome::BiomeZoom, geometry::Direction, position::BlockPos, random::position_seed,
 };
-use horizon_optifine::ctm::connect::{Axes as CtmAxes, Face as CtmFace};
 use horizon_world::{
     block_render::FaceVisibility,
     fluid::{FluidKind, FluidState},
@@ -1872,11 +1871,27 @@ impl Mesher<'_> {
         )
     }
     /// The meshing workers' path: `out`'s buffers and `scratch` are reused
-    /// rather than allocated per section.
+    /// rather than allocated per section. A pack's connected textures mesh through their
+    /// format's entry point ([`crate::connected::Connected::mesh`]).
     pub fn mesh_reusing(
         &mut self,
         region: &[[Option<&Chunk>; 3]; 3],
         sy: i32,
+        out: SectionMesh,
+        scratch: &mut MeshScratch,
+    ) -> SectionMesh {
+        let render = self.render;
+        match &render.connected {
+            Some(connected) => (connected.mesh)(self, &*connected.rules, region, sy, out, scratch),
+            None => self.mesh_with(&NoConnected, region, sy, out, scratch),
+        }
+    }
+    /// [`Self::mesh_reusing`] with the connected textures `connected`.
+    pub fn mesh_with<C: ConnectedTextures>(
+        &mut self,
+        connected: &C,
+        region: &[[Option<&Chunk>; 3]; 3],
+        sy: i32,
         mut out: SectionMesh,
         scratch: &mut MeshScratch,
     ) -> SectionMesh {
@@ -2021,7 +2036,6 @@ impl Mesher<'_> {
                                 )
                                 .unwrap_or(true);
                     }
-                    let connected = &self.render.connected;
                     let start = [out.solid.len(), out.translucent.len()];
                     for model in &models {
                         for face in &model.faces {
@@ -2052,6 +2066,7 @@ impl Mesher<'_> {
                                 }
                             }
                             self.face(
+                                connected,
                                 pad,
                                 &mut tints,
                                 &mut out,
@@ -2102,8 +2117,9 @@ impl Mesher<'_> {
         })
     }
     #[allow(clippy::too_many_arguments)]
-    fn face(
+    fn face<C: ConnectedTextures>(
         &self,
+        connected: &C,
         pad: &Padded,
         tints: &mut Tints,
         out: &mut SectionMesh,
@@ -2163,55 +2179,40 @@ impl Mesher<'_> {
             }
             None => tint,
         };
-        // Fusion's and then OptiFine's connected textures: another sprite, or one per quarter,
-        // and the overlays drawn over it (a few per face at most; more are dropped).
-        let (fusion, connected) = (&self.render.fusion, &self.render.connected);
+        // Connected textures: another sprite, or one per quarter, and the overlays drawn over it
+        // (a few per face at most; more are dropped).
         let mut overlays = [None; 8];
         let mut count = 0;
-        let mut push = |overlay| {
-            if let Some(slot) = overlays.get_mut(count) {
-                *slot = Some(overlay);
-                count += 1;
-            }
-        };
-        let neighbour = |n: [i32; 3]| pad.blocks[(cell as isize + step_index(n)) as usize];
-        let fused = face.fusion.and_then(|rule| {
-            fusion.pick(
-                rule,
-                id,
-                CtmFace::ALL[q.facing as usize],
-                q.tint_index,
-                neighbour,
+        let pick = if connected.is_empty() {
+            Pick::Keep
+        } else {
+            let mut push = |overlay| {
+                if let Some(slot) = overlays.get_mut(count) {
+                    *slot = Some(overlay);
+                    count += 1;
+                }
+            };
+            let tints = &*tints;
+            connected.pick(
+                &crate::connected::Face {
+                    state: id,
+                    layer: face.layer as u16,
+                    facing: q.facing as u8,
+                    pos: [world.x, world.y, world.z],
+                    positions: &q.positions,
+                    uv: &q.uv,
+                    pane: state.pane,
+                    tint_index: q.tint_index,
+                    rule: face.fusion,
+                },
+                |n: [i32; 3]| pad.blocks[(cell as isize + step_index(n)) as usize],
                 |s| {
                     self.tables
                         .info
                         .get(s as usize)
                         .is_some_and(|i| i.opaque_cube)
                 },
-                &mut push,
-            )
-        });
-        let pick = if let Some(pick) = fused {
-            pick
-        } else if connected.is_empty() {
-            Pick::Keep
-        } else {
-            let tints = &*tints;
-            connected.pick(
-                id,
-                face.layer as u16,
-                CtmFace::ALL[q.facing as usize],
-                [world.x, world.y, world.z],
-                neighbour,
                 || Some(tints.biome(pos[0], pos[1], pos[2])),
-                // A pane's tiles are drawn with the cube's UVs (below), so that is its texture.
-                || {
-                    if state.pane {
-                        Some(CtmAxes::cube(CtmFace::ALL[q.facing as usize]))
-                    } else {
-                        CtmAxes::texture(&q.positions, &q.uv)
-                    }
-                },
                 &mut push,
             )
         };

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

@@ -100,8 +100,7 @@ fn fixture() -> (Scratch, Assets, RenderAssets, MeshTables, Biomes) {
         pbr_normals: vec![],
         pbr_specular: vec![],
         pbr_size: 1,
-        connected: Default::default(),
-        fusion: Default::default(),
+        connected: None,
         generation: 1,
     };
     let assets = Assets {

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

@@ -1501,7 +1501,7 @@ pub enum Event {
     /// ones that differ from their defaults (the others went back to theirs).
     PackOptions {
         entries: Vec<String>,
-        chosen: std::collections::BTreeMap<String, horizon_polytone::pack::ConfigValue>,
+        chosen: std::collections::BTreeMap<String, horizon_pack_options::ConfigValue>,
     },
     /// An accepted button press or the release of a slider.
     ButtonClick,
@@ -1688,7 +1688,7 @@ pub struct OptionsUi {
     /// The Pack Options page, and the packs' Polytone config entries by pack id (the game
     /// fills them beside `pack_infos`).
     pub pack_options: crate::pack_options_ui::PackOptionsUi,
-    pub pack_configs: std::collections::BTreeMap<String, horizon_polytone::pack::Configs>,
+    pub pack_configs: std::collections::BTreeMap<String, horizon_pack_options::Configs>,
     pub split_profiles: crate::split_profiles::SplitProfiles,
     /// HDR calibration while its page is open.
     pub calibration: Option<crate::hdr_calibration::Calibration>,
@@ -4018,7 +4018,7 @@ impl OptionsUi {
                     events.push(Event::DownloadPack(i));
                 }
                 crate::pack_screen::Action::Options(id) => {
-                    let mut configs = horizon_polytone::pack::Configs::default();
+                    let mut configs = horizon_pack_options::Configs::default();
                     if let Some(own) = self.pack_configs.get(&id) {
                         configs.merge(own);
                     }

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

@@ -171,7 +171,7 @@ impl OptionsUi {
                 added::Row::Text { text, .. } => {
                     out.extend(wrap(&text, 64).into_iter().map(Row::Note))
                 }
-                added::Row::Space(_) | added::Row::Field { .. } => continue,
+                added::Row::Space(_) => continue,
                 added::Row::Button {
                     label,
                     active,

crates/horizon-client-render/src/pack_formats/block_entity_cem.rs

@@ -12,6 +12,7 @@
 //! block models here, so their files are not read; copper golem statues have no CEM name.
 
 use crate::block_entity_render::ModelPart;
+use crate::pack_hooks::Reshaped;
 use horizon_optifine::cem::{
     files::{atlas_name, jem_files, load_jem},
     model::{Bone, EntityModel},
@@ -140,12 +141,6 @@ const TARGETS: &[Target] = &[
     model("decorated_pot_sides", &["decorated_pot"], POT_SIDES),
 ];
 
-/// Every model, reshaped or vanilla's, and the atlas names of the `.jem` textures by model.
-pub type Reshaped = (
-    HashMap<&'static str, ModelPart>,
-    HashMap<&'static str, String>,
-);
-
 /// The models the packs under `root` reshape, over `vanilla`'s; None when no block entity has
 /// a `.jem` there.
 pub fn reshape(root: &Path, vanilla: &HashMap<&'static str, ModelPart>) -> Option<Reshaped> {

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

@@ -0,0 +1,969 @@
+//! OptiFine's Custom Item Textures (and CIT Resewn's): the rules of the enabled packs'
+//! `optifine/cit/**/*.properties`, read from the overlay resource root, and which of them a stack
+//! matches ([`crate::cit::Matcher`]). The rules themselves are `horizon_optifine::cit`'s; the
+//! engine gets them as [`crate::cit::Rule`]s.
+
+use super::cit_glint::{load_global, stack_glint};
+use crate::cit::{self as engine, CitRules};
+use crate::cit_glint::StackGlint;
+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::{
+    Blend, ComponentTest, Factor, Glint, Global, Hand, Kind, Rule, 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::{Arc, 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| {
+            let props = read_properties(&root.join(&path))?;
+            let rule = Rule::parse(&path, &props, |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
+}
+
+/// A `.properties` file as CIT Resewn reads them (`Properties::parse_equals_first`): UTF-8,
+/// else Latin-1 as Java reads them, so a pack saved that way still loads. `None` when it can't
+/// be read.
+pub fn read_properties(path: &Path) -> Option<Properties> {
+    let bytes = fs::read(path).ok()?;
+    let text = String::from_utf8(bytes)
+        .unwrap_or_else(|e| e.into_bytes().iter().map(|&b| char::from(b)).collect());
+    Some(Properties::parse_equals_first(&text))
+}
+
+/// The rules at `root` with the pack's `cit.properties`, as the engine draws and matches them.
+pub fn load(root: &Path) -> CitRules {
+    cit_rules(load_rules(root), load_global(root))
+}
+
+/// `rules` (in priority order, the winner first) under `global`, for the engine.
+pub fn cit_rules(rules: Vec<Rule>, global: Global) -> CitRules {
+    let drawn = rules.iter().map(rule).collect();
+    let use_glint = global.use_glint;
+    CitRules::new(drawn, use_glint, Box::new(Matcher::new(rules, global)))
+}
+
+/// A rule's file as the engine draws it: `text` read as the `.properties` file at `path`, every
+/// file it names taken to exist. For tests and tools.
+pub fn parse_rule(path: &str, text: &str) -> Option<engine::Rule> {
+    Rule::parse(path, &Properties::parse_equals_first(text), |_| true).map(|r| rule(&r))
+}
+
+/// [`parse_rule`] for a rule in the pack at `root`, whose files it looks for there.
+pub fn parse_rule_in(root: &Path, path: &str, text: &str) -> Option<engine::Rule> {
+    let props = Properties::parse_equals_first(text);
+    Rule::parse(path, &props, |p| root.join(p).is_file()).map(|r| rule(&r))
+}
+
+/// Rules from (path, `.properties` text) under the global `cit.properties` text `global`, in
+/// priority order, every file they name taken to exist. For tests and tools.
+pub fn parse_rules(files: &[(&str, &str)], global: &str) -> CitRules {
+    let mut rules: Vec<Rule> = files
+        .iter()
+        .filter_map(|(path, text)| {
+            Rule::parse(path, &Properties::parse_equals_first(text), |_| true)
+        })
+        .collect();
+    rules.sort_by(Rule::priority);
+    cit_rules(
+        rules,
+        Global::parse(&Properties::parse_equals_first(global)),
+    )
+}
+
+/// A `blend=` value as the engine draws it ([`horizon_optifine::cit::parse_blend`]). For tests
+/// and tools.
+pub fn parse_blend(value: &str) -> Option<Option<engine::Blend>> {
+    horizon_optifine::cit::parse_blend(value).map(|b| b.map(blend))
+}
+
+fn rule(r: &Rule) -> engine::Rule {
+    engine::Rule {
+        path: r.path.clone(),
+        kind: kind(r.kind),
+        texture: r.texture.clone(),
+        textures: r.textures.clone(),
+        model: r.model.clone(),
+        models: r.models.clone(),
+        glint: glint(&r.glint),
+    }
+}
+
+fn kind(k: Kind) -> engine::Kind {
+    match k {
+        Kind::Item => engine::Kind::Item,
+        Kind::Armor => engine::Kind::Armor,
+        Kind::Elytra => engine::Kind::Elytra,
+        Kind::Enchantment => engine::Kind::Enchantment,
+    }
+}
+
+fn of_kind(k: engine::Kind) -> Kind {
+    match k {
+        engine::Kind::Item => Kind::Item,
+        engine::Kind::Armor => Kind::Armor,
+        engine::Kind::Elytra => Kind::Elytra,
+        engine::Kind::Enchantment => Kind::Enchantment,
+    }
+}
+
+fn of_hand(h: engine::Hand) -> Hand {
+    match h {
+        engine::Hand::Any => Hand::Any,
+        engine::Hand::Main => Hand::Main,
+        engine::Hand::Off => Hand::Off,
+    }
+}
+
+fn glint(g: &Glint) -> engine::Glint {
+    engine::Glint {
+        layer: g.layer,
+        blend: g.blend.map(blend),
+        speed: g.speed,
+        rotation: g.rotation,
+        duration: g.duration,
+        rgba: g.rgba,
+        use_glint: g.use_glint,
+        blur: g.blur,
+    }
+}
+
+fn blend(b: Blend) -> engine::Blend {
+    engine::Blend {
+        src: factor(b.src),
+        dst: factor(b.dst),
+        src_alpha: factor(b.src_alpha),
+        dst_alpha: factor(b.dst_alpha),
+    }
+}
+
+fn factor(f: Factor) -> engine::Factor {
+    use engine::Factor as F;
+    match f {
+        Factor::Zero => F::Zero,
+        Factor::One => F::One,
+        Factor::SrcColor => F::SrcColor,
+        Factor::OneMinusSrcColor => F::OneMinusSrcColor,
+        Factor::SrcAlpha => F::SrcAlpha,
+        Factor::OneMinusSrcAlpha => F::OneMinusSrcAlpha,
+        Factor::DstAlpha => F::DstAlpha,
+        Factor::OneMinusDstAlpha => F::OneMinusDstAlpha,
+        Factor::DstColor => F::DstColor,
+        Factor::OneMinusDstColor => F::OneMinusDstColor,
+        Factor::SrcAlphaSaturate => F::SrcAlphaSaturate,
+    }
+}
+
+/// The rules with an index by item and a cache of what each stack matched.
+#[derive(Debug, Default)]
+struct Matcher {
+    rules: Vec<Rule>,
+    /// The pack's `cit.properties`.
+    global: Global,
+    /// 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>>>,
+    glints: Mutex<HashMap<u64, Arc<StackGlint>>>,
+}
+
+#[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 Matcher {
+    /// `rules` in priority order, the winner first.
+    fn new(rules: Vec<Rule>, global: Global) -> 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,
+            global,
+            by_item,
+            any_item,
+            literals,
+            ..Default::default()
+        }
+    }
+
+    /// Whether rule `i` matches the stack drawn in `hand`.
+    fn matches(
+        &self,
+        i: u32,
+        stack: &ItemStack,
+        hand: Hand,
+        max_damage: u32,
+        comps: Option<&Tag>,
+    ) -> bool {
+        let rule = &self.rules[i as usize];
+        if rule.hand != Hand::Any && rule.hand != hand {
+            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)
+    }
+}
+
+impl engine::Matcher for Matcher {
+    fn keep_glints(&mut self, keep: &dyn Fn(usize) -> bool) {
+        self.any_item.retain(|&i| keep(i as usize));
+        let named = &mut self.by_item[Kind::Enchantment as usize];
+        for list in named.values_mut() {
+            list.retain(|&i| keep(i as usize));
+        }
+        named.retain(|_, list| !list.is_empty());
+        lock(&self.enchanted).clear();
+        lock(&self.glints).clear();
+    }
+
+    fn select(
+        &self,
+        kind: engine::Kind,
+        stack: &ItemStack,
+        hand: engine::Hand,
+        max_damage: u32,
+    ) -> Option<usize> {
+        let (kind, hand) = (of_kind(kind), of_hand(hand));
+        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, hand, max_damage, comps.as_ref()));
+        remember(&self.selected, key, found);
+        found.map(|i| i as usize)
+    }
+
+    fn enchantments(&self, stack: &ItemStack, hand: engine::Hand, max_damage: u32) -> Vec<usize> {
+        let hand = of_hand(hand);
+        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),
+            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, hand, max_damage, comps.as_ref()));
+            remember(&self.enchanted, key, all.clone());
+            all
+        });
+        found.into_iter().map(|i| i as usize).collect()
+    }
+
+    /// Worked out once per stack and hand.
+    fn glint(
+        &self,
+        stack: &ItemStack,
+        hand: engine::Hand,
+        max_damage: u32,
+        foil: bool,
+    ) -> Option<Arc<StackGlint>> {
+        let no_rules =
+            self.any_item.is_empty() && self.by_item[Kind::Enchantment as usize].is_empty();
+        // Before the cache, which `foil` is not part of.
+        if !foil || (no_rules && self.global.use_glint) {
+            return None;
+        }
+        let comps = encode_components(stack);
+        let key = cache_key(
+            (2, Kind::Enchantment, of_hand(hand)),
+            stack,
+            max_damage,
+            comps.as_ref(),
+        );
+        if let Some(hit) = lock(&self.glints).get(&key) {
+            return Some(hit.clone());
+        }
+        let matched = self.enchantments(stack, hand, max_damage);
+        let glint = Arc::new(stack_glint(
+            &self.rules,
+            &matched,
+            stack.crafting_enchantments(),
+            &self.global,
+        ));
+        remember(&self.glints, key, glint.clone());
+        Some(glint)
+    }
+}
+
+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`, `enchantments` and `glint` apart.
+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 crate::cit::{Hand, Kind};
+    use std::sync::Arc;
+
+    /// Rules from (file stem, properties), sorted as `load_rules` sorts them, under the global
+    /// `cit.properties` text `global`.
+    fn rules_under(files: &[(&str, &str)], global: &str) -> CitRules {
+        let files: Vec<(String, String)> = files
+            .iter()
+            .map(|(stem, text)| {
+                let path = format!("assets/minecraft/optifine/cit/{stem}.properties");
+                (path, format!("texture=x\n{text}"))
+            })
+            .collect();
+        let files: Vec<(&str, &str)> = files.iter().map(|(p, t)| (&**p, &**t)).collect();
+        let cit = parse_rules(&files, global);
+        assert_eq!(cit.rules.len(), files.len(), "every rule parses");
+        cit
+    }
+
+    fn rules(files: &[(&str, &str)]) -> CitRules {
+        rules_under(files, "")
+    }
+
+    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, Hand::Main, 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);
+    }
+
+    /// `CitRules::glint` in the main hand, with the stack's own `has_foil` as callers pass it.
+    fn glint(cit: &CitRules, stack: &ItemStack, item_glint: bool) -> Option<Arc<StackGlint>> {
+        cit.glint(stack, Hand::Main, 0, stack.has_foil(item_glint))
+    }
+
+    /// `stack` with its `enchantment_glint_override` set to `on`.
+    fn overridden(mut stack: ItemStack, on: bool) -> ItemStack {
+        let flag = (
+            "minecraft:enchantment_glint_override".to_owned(),
+            Tag::Byte(on.into()),
+        );
+        stack.data_mut().other.push(flag);
+        stack
+    }
+
+    #[test]
+    fn a_stack_glint_reads_the_book_and_the_pack_file() {
+        let files = [
+            ("sharp", "type=enchantment\nenchantments=sharpness"),
+            (
+                "keep",
+                "type=enchantment\nlayer=1\nuseGlint=true\nenchantments=mending",
+            ),
+        ];
+        let cit = rules(&files);
+        // An enchanted book's glint follows its stored enchantments.
+        let mut book = new("enchanted_book");
+        book.data_mut().stored_enchantments = vec![
+            (Arc::from("minecraft:sharpness"), 3),
+            (Arc::from("minecraft:mending"), 1),
+        ];
+        let book = glint(&cit, &book, true).unwrap();
+        let weights: Vec<_> = book.layers.iter().map(|l| l.weight).collect();
+        assert_eq!(weights, [0.75, 0.25]);
+        assert!(book.vanilla);
+        let plain = glint(&cit, &enchanted("stick", &[("sharpness", 1)]), false).unwrap();
+        assert_eq!(plain.layers.len(), 1);
+        assert!(!plain.vanilla);
+        // No enchantment rules: nothing changes, unless the pack turns vanilla's glint off.
+        let bare = rules(&[("stick", "items=stick")]);
+        assert!(glint(&bare, &overridden(new("stick"), true), false).is_none());
+        let bare = rules_under(&[("stick", "items=stick")], "useGlint=false");
+        assert!(!bare.use_glint);
+        assert!(
+            !glint(&bare, &overridden(new("stick"), true), false)
+                .unwrap()
+                .vanilla
+        );
+        let cit = rules_under(&files, "useGlint=false");
+        assert!(
+            glint(&cit, &overridden(new("stick"), true), false)
+                .unwrap()
+                .is_empty()
+        );
+    }
+
+    #[test]
+    fn only_a_stack_with_a_glint_gets_layers() {
+        let cit = rules(&[("any", "type=enchantment")]);
+        assert!(glint(&cit, &new("stick"), false).is_none());
+        // The override turns an enchanted stack's glint off, and an unenchanted one's on.
+        let off = overridden(enchanted("stick", &[("sharpness", 1)]), false);
+        assert!(glint(&cit, &off, false).is_none());
+        let on = glint(&cit, &overridden(new("stick"), true), false).unwrap();
+        let weights: Vec<_> = on.layers.iter().map(|l| l.weight).collect();
+        assert_eq!(
+            weights,
+            [1.0],
+            "nothing to share: the rule at full strength"
+        );
+        // The same stack, asked again without its glint, is not answered from the cache.
+        assert!(
+            cit.glint(&overridden(new("stick"), true), Hand::Main, 0, false)
+                .is_none()
+        );
+    }
+
+    #[test]
+    fn a_rule_left_out_of_the_glints_matches_nothing() {
+        let mut cit = rules(&[
+            ("broken", "type=enchantment\nitems=diamond_sword\nweight=1"),
+            ("shown", "type=enchantment"),
+        ]);
+        let sword = enchanted("diamond_sword", &[("sharpness", 1)]);
+        let layers = |cit: &CitRules| -> Vec<String> {
+            let glint = glint(cit, &sword, false).unwrap();
+            let stems = glint
+                .layers
+                .iter()
+                .map(|l| stem(cit, Some(l.rule)).unwrap());
+            stems.map(str::to_owned).collect()
+        };
+        // The heavier rule wins the layer, until its texture is missing.
+        assert_eq!(layers(&cit), ["broken"]);
+        let broken = (0..cit.rules.len())
+            .find(|&i| stem(&cit, Some(i)) == Some("broken"))
+            .unwrap();
+        cit.keep_glints(|i| i != broken);
+        assert_eq!(layers(&cit), ["shown"]);
+        assert_eq!(cit.enchantments(&sword, Hand::Main, 0).len(), 1);
+        // None left: vanilla's glint stays.
+        cit.keep_glints(|_| false);
+        assert!(glint(&cit, &sword, false).is_none());
+    }
+
+    #[test]
+    fn an_off_hand_layer_draws_only_in_the_off_hand() {
+        let cit = rules(&[
+            ("left", "type=enchantment\nlayer=1\nhand=off"),
+            ("both", "type=enchantment"),
+        ]);
+        let sword = enchanted("diamond_sword", &[("sharpness", 1)]);
+        let layers = |hand| -> Vec<&str> {
+            let glint = cit.glint(&sword, hand, 0, true).unwrap();
+            glint
+                .layers
+                .iter()
+                .map(|l| stem(&cit, Some(l.rule)).unwrap())
+                .collect()
+        };
+        assert_eq!(layers(Hand::Off), ["both", "left"]);
+        // Asked in this order, a cache keyed without the hand would answer as for the off hand.
+        assert_eq!(layers(Hand::Main), ["both"]);
+    }
+}

crates/horizon-client-render/src/pack_formats/cit_glint.rs

@@ -0,0 +1,301 @@
+//! OptiFine's Custom Item Textures' enchantment glints (`type=enchantment`): which of a stack's
+//! matching rules draw, in which order and how strongly, and whether vanilla's glint still draws
+//! under them ([`crate::cit_glint::StackGlint`]). The pack's `cit.properties` (`Global`) says how
+//! layers share an item.
+//!
+//! Written from OptiFine's `cit.properties` doc and CIT Resewn's (MIT) `TypeEnchantment` of
+//! before its 1.21.11 port, which implemented `method`, `cap` and `fade`: the sums and the
+//! cycle's fading follow it, except where noted.
+
+use super::cit::read_properties;
+use crate::cit_glint::{GlintLayer, StackGlint};
+use horizon_optifine::cit::{Global, Method, Rule};
+use std::path::Path;
+
+/// The pack's global `cit.properties` under the overlay resource root: the first of
+/// `Global::PATHS` that exists, else the defaults.
+pub fn load_global(root: &Path) -> Global {
+    Global::PATHS
+        .iter()
+        .find_map(|path| read_properties(&root.join(path)))
+        .map(|props| Global::parse(&props))
+        .unwrap_or_default()
+}
+
+/// A stack's glint: the layers among `matched` (its matching enchantment rules, in priority
+/// order, as `CitRules::enchantments` gives them) that draw, for a stack with `enchantments`
+/// (`ItemStack::crafting_enchantments`).
+pub fn stack_glint(
+    rules: &[Rule],
+    matched: &[usize],
+    enchantments: &[(impl AsRef<str>, u32)],
+    global: &Global,
+) -> StackGlint {
+    // The highest priority rule of each layer.
+    let mut layers: Vec<usize> = Vec::new();
+    for &i in matched {
+        let layer = rules[i].glint.layer;
+        if !layers.iter().any(|&j| rules[j].glint.layer == layer) {
+            layers.push(i);
+        }
+    }
+    layers.sort_by_key(|&i| rules[i].glint.layer);
+    let cycle = global.method == Method::Cycle;
+    // OptiFine's doc: `cap` is for `average` and `layered`, and keeps the topmost layers.
+    // `none`, which OptiFine lacks, is capped too, as CIT Resewn caps every method (it keeps
+    // the bottom layers, though, and caps cycles as well).
+    if let Some(cap) = global.cap.filter(|_| !cycle) {
+        let cap = usize::try_from(cap).unwrap_or(usize::MAX);
+        layers = layers.split_off(layers.len().saturating_sub(cap));
+    }
+    // CIT Resewn: any layer left asking for vanilla's glint keeps it, and the global
+    // `useGlint=false` removes it everywhere, as OptiFine's doc says too. `cap=0` leaves no
+    // custom layer, and vanilla's glint only if the pack's `useGlint` allows it.
+    let vanilla =
+        global.use_glint && (layers.is_empty() || layers.iter().any(|&i| rules[i].glint.use_glint));
+    // CIT Resewn: shares are against every enchantment of the stack, not only those the
+    // layers name.
+    let levels = enchantments.iter().map(|(_, level)| *level as f32);
+    let total = match global.method {
+        Method::Average => levels.sum::<f32>(),
+        Method::Layered => levels.fold(0.0, f32::max),
+        Method::None | Method::Cycle => 0.0,
+    };
+    let shared = matches!(global.method, Method::Average | Method::Layered);
+    let layers = layers
+        .into_iter()
+        .map(|i| {
+            let rule = &rules[i];
+            let named = &rule.enchantments;
+            let weight = if !shared || named.is_empty() {
+                1.0
+            } else {
+                // The highest level among the enchantments the rule names whose level also
+                // passes its `enchantmentLevels` (CIT Resewn takes the first named one the
+                // stack has, whatever its level).
+                let in_range = |level: u32| {
+                    let level = i32::try_from(level).unwrap_or(i32::MAX);
+                    rule.enchantment_levels
+                        .as_ref()
+                        .is_none_or(|r| r.contains(level))
+                };
+                let level = enchantments
+                    .iter()
+                    .filter(|(id, level)| {
+                        let id: &str = id.as_ref();
+                        named.iter().any(|n| n == id) && in_range(*level)
+                    })
+                    .map(|(_, level)| *level as f32)
+                    .fold(0.0, f32::max);
+                if total > 0.0 { level / total } else { 0.0 }
+            };
+            GlintLayer::new(i, weight, rule.glint.duration)
+        })
+        .collect();
+    StackGlint::from_parts(layers, vanilla, cycle.then_some(global.fade))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use horizon_optifine::Properties;
+
+    const DIR: &str = "assets/minecraft/optifine/cit";
+
+    /// An enchantment rule named `name` with `text` after `type` and `texture`.
+    fn rule(name: &str, text: &str) -> Rule {
+        let text = format!("type=enchantment\ntexture=glint\n{text}");
+        let path = format!("{DIR}/{name}.properties");
+        Rule::parse(&path, &Properties::parse_equals_first(&text), |_| true).unwrap()
+    }
+
+    fn global(text: &str) -> Global {
+        Global::parse(&Properties::parse_equals_first(text))
+    }
+
+    fn rules_of(layers: &StackGlint) -> Vec<usize> {
+        layers.layers.iter().map(|l| l.rule).collect()
+    }
+
+    const SWORD: [(&str, u32); 2] = [("minecraft:sharpness", 3), ("minecraft:unbreaking", 1)];
+
+    #[test]
+    fn one_rule_per_layer_bottom_first() {
+        let rules = [
+            rule("a", "layer=2"),
+            rule("b", "layer=0"),
+            rule("c", "layer=2"),
+            rule("d", "layer=-1"),
+        ];
+        // Priority order a, b, c, d: c loses layer 2 to a.
+        let g = stack_glint(&rules, &[0, 1, 2, 3], &SWORD, &Global::default());
+        assert_eq!(rules_of(&g), [3, 1, 0]);
+        let g = stack_glint(&rules, &[2, 0], &SWORD, &Global::default());
+        assert_eq!(rules_of(&g), [2]);
+    }
+
+    #[test]
+    fn average_and_layered_shares() {
+        let rules = [
+            rule("sharp", "enchantments=sharpness smite"),
+            rule("unb", "layer=1\nenchantments=unbreaking"),
+            rule("any", "layer=2"),
+            rule("fire", "layer=3\nenchantments=fire_aspect"),
+        ];
+        let weights = |method: &str| {
+            let g = stack_glint(&rules, &[0, 1, 2, 3], &SWORD, &global(method));
+            g.layers.iter().map(|l| l.weight).collect::<Vec<_>>()
+        };
+        // Sharpness III and Unbreaking I: 3 / 4 and 1 / 4; against the highest, 3 / 3 and 1 / 3.
+        // A rule naming no enchantment is at full strength, one the stack lacks at none.
+        assert_eq!(weights("method=average"), [0.75, 0.25, 1.0, 0.0]);
+        assert_eq!(weights("method=layered"), [1.0, 1.0 / 3.0, 1.0, 0.0]);
+        assert_eq!(weights("method=cycle"), [1.0; 4]);
+        assert_eq!(weights("method=none"), [1.0; 4]);
+    }
+
+    #[test]
+    fn the_level_is_one_the_rules_levels_allow() {
+        let rules = [rule(
+            "holy",
+            "enchantments=sharpness smite\nenchantmentLevels=1-2",
+        )];
+        // Sharpness V is out of range, so Smite I sets the share: 1 / 5 of the highest level.
+        let stack = [("minecraft:sharpness", 5), ("minecraft:smite", 1)];
+        let g = stack_glint(&rules, &[0], &stack, &global("method=layered"));
+        assert_eq!(g.layers[0].weight, 1.0 / 5.0);
+    }
+
+    #[test]
+    fn cap_keeps_the_topmost_layers() {
+        let rules = [
+            rule("a", "layer=0"),
+            rule("b", "layer=1"),
+            rule("c", "layer=2"),
+        ];
+        let g = stack_glint(&rules, &[0, 1, 2], &SWORD, &global("cap=2"));
+        assert_eq!(rules_of(&g), [1, 2]);
+        let g = stack_glint(&rules, &[0, 1, 2], &SWORD, &global("cap=0"));
+        assert!(g.is_empty());
+        let g = stack_glint(&rules, &[0, 1, 2], &SWORD, &global("cap=1\nmethod=none"));
+        assert_eq!(rules_of(&g), [2]);
+        // Cycles show every layer in turn.
+        let g = stack_glint(&rules, &[0, 1, 2], &SWORD, &global("cap=1\nmethod=cycle"));
+        assert_eq!(rules_of(&g), [0, 1, 2]);
+    }
+
+    #[test]
+    fn vanilla_glint() {
+        let plain = rule("plain", "");
+        let keep = rule("keep", "layer=1\nuseGlint=true");
+        let rules = [plain, keep];
+        let vanilla = |matched: &[usize], text: &str| {
+            stack_glint(&rules, matched, &SWORD, &global(text)).vanilla
+        };
+        assert!(vanilla(&[], ""), "no rule: vanilla's glint");
+        assert!(!vanilla(&[0], ""), "a rule replaces it");
+        assert!(vanilla(&[0, 1], ""), "unless one keeps it");
+        assert!(!vanilla(&[], "useGlint=false"));
+        assert!(!vanilla(&[1], "useGlint=false"), "the pack's word is final");
+        // Only the layers `cap` keeps count.
+        let rules = [rule("keep", "useGlint=true"), rule("top", "layer=1")];
+        let g = stack_glint(&rules, &[0, 1], &SWORD, &global("cap=1"));
+        assert!(!g.vanilla);
+        let g = stack_glint(&rules, &[0, 1], &SWORD, &global("cap=0"));
+        assert!(g.is_empty() && g.vanilla);
+        let g = stack_glint(&rules, &[0, 1], &SWORD, &global("cap=0\nuseGlint=false"));
+        assert!(!g.vanilla);
+    }
+
+    #[test]
+    fn cycles_take_turns_and_fade() {
+        let rules = [
+            rule("a", "duration=2"),
+            rule("b", "layer=1\nduration=1"),
+            rule("c", "layer=2\nduration=1"),
+        ];
+        let g = stack_glint(
+            &rules,
+            &[0, 1, 2],
+            &SWORD,
+            &global("method=cycle\nfade=0.5"),
+        );
+        // a 0-2, a→b 2-2.5, b 2.5-3.5, b→c 3.5-4, c 4-5, c→a 5-5.5, then again.
+        let at = |t: f64| [0, 1, 2].map(|i| g.intensity(i, t));
+        assert_eq!(at(1.0), [1.0, 0.0, 0.0]);
+        assert_eq!(at(2.125), [0.75, 0.25, 0.0]);
+        assert_eq!(at(3.0), [0.0, 1.0, 0.0]);
+        assert_eq!(at(3.75), [0.0, 0.5, 0.5]);
+        assert_eq!(at(4.5), [0.0, 0.0, 1.0]);
+        assert_eq!(at(5.25), [0.5, 0.0, 0.5]);
+        assert_eq!(at(5.5 + 3.0), [0.0, 1.0, 0.0]);
+        // One layer always shows.
+        let one = stack_glint(&rules, &[1], &SWORD, &global("method=cycle"));
+        assert_eq!(one.intensity(0, 0.7), 1.0);
+    }
+
+    #[test]
+    fn a_cycle_always_shows_a_whole_layer() {
+        let rules = [
+            rule("a", "duration=0.1"),
+            rule("b", "layer=1\nduration=0.7"),
+            rule("c", "layer=2\nduration=0.2"),
+        ];
+        let g = stack_glint(
+            &rules,
+            &[0, 1, 2],
+            &SWORD,
+            &global("method=cycle\nfade=0.3"),
+        );
+        // Every millisecond of the first two seconds, and just under a period, the last fade's
+        // end. (Rounding has not been seen to leave time past it; the last fade's clamp is
+        // defensive.)
+        let period: f64 = [0.1f32, 0.7, 0.2]
+            .map(|d| f64::from(d) + f64::from(0.3f32))
+            .iter()
+            .sum();
+        let last = f64::from_bits(period.to_bits() - 1);
+        for t in (0..2000_i32)
+            .map(|i| f64::from(i) * 0.001)
+            .chain([last, period + last])
+        {
+            let sum: f32 = (0..3).map(|i| g.intensity(i, t)).sum();
+            assert!((sum - 1.0).abs() < 1e-5, "{sum} at {t}");
+        }
+        // No time at all: the bottom layer alone, never NaN.
+        let still = [rule("a", "duration=0"), rule("b", "layer=1\nduration=0")];
+        let g = stack_glint(&still, &[0, 1], &SWORD, &global("method=cycle\nfade=0"));
+        for t in [0.0, 0.5, 7.25] {
+            assert_eq!([0, 1].map(|i| g.intensity(i, t)), [1.0, 0.0]);
+        }
+    }
+
+    #[test]
+    fn the_first_global_file_wins() {
+        let root = std::env::temp_dir().join(format!("horizon-cit-glint-{}", std::process::id()));
+        let _ = std::fs::remove_dir_all(&root);
+        assert_eq!(load_global(&root), Global::default());
+        let write = |path: &str, text: &[u8]| {
+            let file = root.join(path);
+            std::fs::create_dir_all(file.parent().unwrap()).unwrap();
+            std::fs::write(file, text).unwrap();
+        };
+        // Saved as Latin-1 (`é` is not UTF-8 alone), in the OptiFine doc's `cit/` folder.
+        write(
+            "assets/minecraft/optifine/cit/cit.properties",
+            b"# caf\xE9\nmethod=cycle",
+        );
+        assert_eq!(load_global(&root).method, Method::Cycle);
+        write("assets/minecraft/mcpatcher/cit.properties", b"method=none");
+        assert_eq!(load_global(&root).method, Method::Cycle);
+        write(
+            "assets/minecraft/optifine/cit.properties",
+            b"method=layered",
+        );
+        assert_eq!(load_global(&root).method, Method::Layered);
+        write("assets/minecraft/citresewn/cit.properties", b"cap=1");
+        let g = load_global(&root);
+        let _ = std::fs::remove_dir_all(&root);
+        assert_eq!((g.method, g.cap), (Method::Average, Some(1)));
+    }
+}

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

@@ -0,0 +1,136 @@
+//! OptiFine's and Fusion's connected textures as the mesher draws them
+//! ([`crate::connected::ConnectedTextures`]): a Fusion face first, then OptiFine's rules.
+
+use std::path::Path;
+use std::sync::Arc;
+
+use horizon_optifine::ctm::connect::{Axes, Face};
+use horizon_world::registry::{BlockRegistry, BlockStateId};
+
+use super::ctm::ConnectedTextures as Ctm;
+use super::fusion::FusionTextures;
+use crate::chunk::Chunk;
+use crate::connected::{self as engine, Connected, ConnectedTextures, Overlay, Pick};
+use crate::mesher::{MeshScratch, Mesher, SectionMesh};
+use crate::models::StateModels;
+use crate::sprites::Sprites;
+
+/// A pack's Fusion and OptiFine connected textures.
+pub struct Rules {
+    ctm: Ctm,
+    fusion: FusionTextures,
+}
+
+/// The connected textures under `root`: Fusion's models' tiles, native mods' sprites, then
+/// OptiFine's rules' tiles go into `sprites`, in that order. `None` without either format's files.
+pub fn load(
+    root: &Path,
+    registry: &BlockRegistry,
+    sprites: &mut Sprites,
+    models: &mut StateModels,
+    native_mods: &mut dyn FnMut(&mut Sprites),
+) -> Option<Connected> {
+    let fusion = {
+        let _step = crate::spans::startup::step("core.fusion");
+        FusionTextures::load(root, registry, sprites, models)
+    };
+    native_mods(sprites);
+    // A side's sprite, for rules that connect by tile: the first quad facing it.
+    let catalog = &*models;
+    let mut found = Vec::new();
+    let ctm = Ctm::load(
+        root,
+        registry,
+        sprites,
+        |state: BlockStateId, face: 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)
+        },
+    );
+    let rules = Rules { ctm, fusion };
+    (!rules.is_empty()).then(|| Connected {
+        rules: Arc::new(rules),
+        mesh,
+    })
+}
+
+/// The mesher on [`Rules`].
+fn mesh(
+    mesher: &mut Mesher<'_>,
+    rules: &(dyn std::any::Any + Send + Sync),
+    region: &[[Option<&Chunk>; 3]; 3],
+    sy: i32,
+    out: SectionMesh,
+    scratch: &mut MeshScratch,
+) -> SectionMesh {
+    let rules = rules
+        .downcast_ref::<Rules>()
+        .expect("the connected textures this format loaded");
+    mesher.mesh_with(rules, region, sy, out, scratch)
+}
+
+impl ConnectedTextures for Rules {
+    fn is_empty(&self) -> bool {
+        self.ctm.is_empty() && self.fusion.is_empty()
+    }
+
+    fn stacked_pane_hides(&self, state: u32, other: u32, centre: [f32; 2]) -> bool {
+        !self.ctm.is_empty() && self.ctm.stacked_pane_hides(state, other, centre)
+    }
+
+    fn pick<'b>(
+        &self,
+        face: &engine::Face,
+        neighbour: impl Fn([i32; 3]) -> u32,
+        covers: impl Fn(u32) -> bool,
+        biome: impl Fn() -> Option<&'b str>,
+        mut overlay: impl FnMut(Overlay),
+    ) -> Pick {
+        let side = Face::ALL[usize::from(face.facing)];
+        let fused = face.rule.and_then(|rule| {
+            self.fusion.pick(
+                rule,
+                face.state,
+                side,
+                face.tint_index,
+                &neighbour,
+                covers,
+                &mut overlay,
+            )
+        });
+        if let Some(pick) = fused {
+            pick
+        } else if self.ctm.is_empty() {
+            Pick::Keep
+        } else {
+            self.ctm.pick(
+                face.state,
+                face.layer,
+                side,
+                face.pos,
+                &neighbour,
+                biome,
+                // A pane's tiles are drawn with the cube's UVs, so that is its texture.
+                || {
+                    if face.pane {
+                        Some(Axes::cube(side))
+                    } else {
+                        Axes::texture(face.positions, face.uv)
+                    }
+                },
+                &mut overlay,
+            )
+        }
+    }
+}

crates/horizon-client-render/src/pack_formats/entity_textures.rs

@@ -0,0 +1,88 @@
+//! OptiFine's random entity textures and ETF's blinking and emissive textures
+//! (`horizon_optifine::{random_textures, blink, emissive}`) as the engine's
+//! [`crate::entity_textures`] tables.
+
+use crate::entity_textures::{
+    self as engine, Blink, Blinks, Emissive, EntityTextures, Entry, RandomTextures,
+};
+use horizon_optifine::random::{self, Rules};
+use std::path::Path;
+
+/// The pack's variants, blinks and emissive overlays under the overlay resource root.
+pub fn load(root: &Path) -> EntityTextures {
+    let random = horizon_optifine::random_textures::RandomTextures::scan(root);
+    let blinks = horizon_optifine::blink::Blinks::scan(root, &random);
+    let mut emissive = horizon_optifine::emissive::Emissive::scan(root, &random);
+    emissive.pair_beside(root, blinks.files());
+    let files = random
+        .files()
+        .map(|(f, n)| (f.to_owned(), n.to_owned()))
+        .collect();
+    let generation = random.generation();
+    let (entries, rules) = random.into_parts();
+    let entries = entries
+        .into_iter()
+        .map(|(texture, entry)| {
+            let variants = entry
+                .variant_names()
+                .map(|(n, name)| (n, name.to_owned()))
+                .collect();
+            let rules = entry.rules;
+            (texture, Entry { rules, variants })
+        })
+        .collect();
+    let (blinks, blink_files) = blinks.into_parts();
+    let blinks = blinks
+        .into_iter()
+        .map(|(texture, b)| {
+            let blink = Blink {
+                shut: b.shut,
+                half: b.half,
+                length: b.length,
+                frequency: b.frequency,
+            };
+            (texture, blink)
+        })
+        .collect();
+    let (suffix, overlays, overlay_files) = emissive.into_parts();
+    EntityTextures {
+        random: RandomTextures::new(entries, files, Box::new(Variants(rules)), generation),
+        blinks: Blinks::new(blinks, blink_files),
+        emissive: Emissive::new(suffix, overlays, overlay_files),
+    }
+}
+
+/// The rule files of a scan.
+struct Variants(Vec<Rules>);
+
+impl engine::VariantRules for Variants {
+    fn matching(&self, rules: usize, facts: &engine::Facts, seed: i32) -> Option<u32> {
+        let blocks: Vec<random::Block> = facts
+            .blocks
+            .iter()
+            .map(|b| random::Block {
+                id: b.id,
+                states: b.states,
+            })
+            .collect();
+        let facts = random::Facts {
+            biome: facts.biome,
+            y: facts.y,
+            blocks: &blocks,
+            name: facts.name,
+            profession: facts.profession,
+            color: facts.color,
+            baby: facts.baby,
+            health: facts.health,
+            moon_phase: facts.moon_phase,
+            day_time: facts.day_time,
+            weather: facts.weather.map(|w| match w {
+                engine::Weather::Clear => random::Weather::Clear,
+                engine::Weather::Rain => random::Weather::Rain,
+                engine::Weather::Thunder => random::Weather::Thunder,
+            }),
+            size: facts.size,
+        };
+        self.0.get(rules)?.matching(&facts, seed)
+    }
+}

crates/horizon-client-render/src/pack_formats/fusion.rs

@@ -273,6 +273,10 @@ fn sheet(
 }
 
 impl FusionTextures {
+    pub fn is_empty(&self) -> bool {
+        self.rules.is_empty()
+    }
+
     /// The connecting textures under `root`: the tiles of those `fusion:connecting` models
     /// draw are inserted into `sprites` (before it finishes), and each face in `catalog` that
     /// shows one gets its rule.

crates/horizon-client-render/src/pack_formats/mod.rs

@@ -3,9 +3,17 @@
 //! crate until the platform's executable installs it: it uses only the crate's public API, so it
 //! moves to a platform crate unchanged, and nothing else in the crate names it.
 
+pub(crate) mod block_entity_cem;
+pub mod cit;
+mod cit_glint;
 mod colors;
+mod connected;
+mod ctm;
 mod custom_sky;
+mod entity_textures;
+mod fusion;
 mod item_bars;
+mod pack_options;
 
 use std::path::Path;
 use std::sync::Arc;
@@ -20,15 +28,63 @@ impl PackFormats for Formats {
         Some(colors::read(root))
     }
 
+    fn connected_textures(
+        &self,
+        root: &Path,
+        registry: &horizon_world::registry::BlockRegistry,
+        sprites: &mut crate::sprites::Sprites,
+        models: &mut crate::models::StateModels,
+        native_mods: &mut dyn FnMut(&mut crate::sprites::Sprites),
+    ) -> Option<crate::connected::Connected> {
+        connected::load(root, registry, sprites, models, native_mods)
+    }
+
     fn emissive_suffix(&self, root: &Path) -> Option<String> {
         Some(horizon_optifine::emissive::suffix(root))
     }
 
+    fn item_textures(&self, root: &Path) -> Option<crate::cit::CitRules> {
+        Some(cit::load(root))
+    }
+
+    fn entity_textures(&self, root: &Path) -> Option<crate::entity_textures::EntityTextures> {
+        Some(entity_textures::load(root))
+    }
+
+    fn block_entity_models(
+        &self,
+        root: &Path,
+        vanilla: &std::collections::HashMap<&'static str, crate::block_entity_render::ModelPart>,
+    ) -> Option<crate::pack_hooks::Reshaped> {
+        block_entity_cem::reshape(root, vanilla)
+    }
+
     fn custom_sky(&self, root: &Path) -> Option<Arc<dyn crate::custom_sky::SkyLayers>> {
         let sky = custom_sky::CustomSky::load(root);
         (!sky.is_empty()).then(|| Arc::new(sky) as _)
     }
 
+    fn pack_options(&self, source: &crate::packs::Source) -> Option<horizon_pack_options::Configs> {
+        Some(pack_options::read(source))
+    }
+
+    fn overlay_active(
+        &self,
+        entry: &serde_json::Value,
+        options: &horizon_pack_options::Configs,
+        formats_apply: bool,
+    ) -> bool {
+        horizon_polytone::pack::overlay_active(entry, options, formats_apply)
+    }
+
+    fn sounds_without_unmet(
+        &self,
+        text: &[u8],
+        options: &horizon_pack_options::Configs,
+    ) -> Option<Vec<u8>> {
+        horizon_polytone::pack::sounds_without_unmet(text, options)
+    }
+
     fn item_bars(&self, root: &Path) -> Option<Arc<dyn crate::pack_palette::ItemBars>> {
         item_bars::read(root)
     }

crates/horizon-client-render/src/pack_formats/pack_options.rs

@@ -0,0 +1,62 @@
+//! Polytone's pack options (wiki "Polytone Configs") and the `polytone_condition`s that read
+//! them, on pack overlays and on `sounds.json` events.
+
+use crate::packs::Source;
+use crate::zip::Zip;
+use horizon_pack_options::Configs;
+use horizon_polytone::pack::add_entry;
+use std::fs;
+
+/// A pack's Polytone config entries (`assets/<namespace>/polytone/config_entries/<name>.json`,
+/// in the pack's base, not its overlays) at their default values.
+pub fn read(source: &Source) -> Configs {
+    let mut configs = Configs::default();
+    let id_of = |name: &str| -> Option<String> {
+        let rest = name.strip_prefix("assets/")?;
+        let (namespace, rest) = rest.split_once('/')?;
+        let entry = rest
+            .strip_prefix("polytone/config_entries/")?
+            .strip_suffix(".json")?;
+        Some(format!("{namespace}:{entry}"))
+    };
+    match source {
+        Source::Dir(d) => {
+            let Ok(namespaces) = fs::read_dir(d.join("assets")) else {
+                return configs;
+            };
+            for namespace in namespaces.flatten() {
+                let folder = namespace.path().join("polytone/config_entries");
+                for file in fs::read_dir(&folder).into_iter().flatten().flatten() {
+                    let name = format!(
+                        "assets/{}/polytone/config_entries/{}",
+                        namespace.file_name().to_string_lossy(),
+                        file.file_name().to_string_lossy()
+                    );
+                    if let (Some(id), Ok(bytes)) = (id_of(&name), fs::read(file.path()))
+                        && let Ok(json) = serde_json::from_slice(&bytes)
+                    {
+                        add_entry(&mut configs, id, &json);
+                    }
+                }
+            }
+        }
+        Source::Zip(z) => {
+            let Ok(zip) = Zip::open(z) else {
+                return configs;
+            };
+            let names: Vec<String> = zip
+                .names()
+                .filter(|n| id_of(n).is_some())
+                .map(str::to_owned)
+                .collect();
+            for name in names {
+                if let (Some(id), Ok(bytes)) = (id_of(&name), zip.read(&name))
+                    && let Ok(json) = serde_json::from_slice(&bytes)
+                {
+                    add_entry(&mut configs, id, &json);
+                }
+            }
+        }
+    }
+    configs
+}

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

@@ -21,17 +21,87 @@ pub trait PackFormats: Send + Sync {
         None
     }
 
+    /// The overlay's connected textures: their tiles go into `sprites` (before it finishes), and
+    /// baked faces they draw on may get a rule (`crate::models::BakedFace::fusion`).
+    /// `native_mods` loads native mods' own sprites: call it after the tiles that go before them.
+    fn connected_textures(
+        &self,
+        _root: &Path,
+        _registry: &horizon_world::registry::BlockRegistry,
+        _sprites: &mut crate::sprites::Sprites,
+        _models: &mut crate::models::StateModels,
+        _native_mods: &mut dyn FnMut(&mut crate::sprites::Sprites),
+    ) -> Option<crate::connected::Connected> {
+        None
+    }
+
+    /// The overlay's custom item texture rules and their matcher.
+    fn item_textures(&self, _root: &Path) -> Option<crate::cit::CitRules> {
+        None
+    }
+
+    /// The overlay's entity texture variants, blinks and emissive overlays.
+    fn entity_textures(&self, _root: &Path) -> Option<crate::entity_textures::EntityTextures> {
+        None
+    }
+
+    /// The block entity models the overlay reshapes over `vanilla`'s, with their textures;
+    /// `None` when it reshapes none.
+    fn block_entity_models(
+        &self,
+        _root: &Path,
+        _vanilla: &std::collections::HashMap<&'static str, crate::block_entity_render::ModelPart>,
+    ) -> Option<Reshaped> {
+        None
+    }
+
     /// The sky layers the overlay draws over the vanilla sky, if it has any.
     fn custom_sky(&self, _root: &Path) -> Option<Arc<dyn crate::custom_sky::SkyLayers>> {
         None
     }
 
+    /// The options the pack (its base, not its overlays) declares, at their defaults.
+    fn pack_options(
+        &self,
+        _source: &crate::packs::Source,
+    ) -> Option<horizon_pack_options::Configs> {
+        None
+    }
+
+    /// Whether an `overlays.entries[]` item of `pack.mcmeta` is active, given the pack's options;
+    /// `formats_apply` is vanilla's answer from its `formats`.
+    fn overlay_active(
+        &self,
+        _entry: &serde_json::Value,
+        _options: &horizon_pack_options::Configs,
+        formats_apply: bool,
+    ) -> bool {
+        formats_apply
+    }
+
+    /// A pack's `sounds.json` without the events its options turn off; `None` when it keeps
+    /// them all.
+    fn sounds_without_unmet(
+        &self,
+        _text: &[u8],
+        _options: &horizon_pack_options::Configs,
+    ) -> Option<Vec<u8>> {
+        None
+    }
+
     /// The durability bar colours the overlay sets by item, if any.
     fn item_bars(&self, _root: &Path) -> Option<Arc<dyn crate::pack_palette::ItemBars>> {
         None
     }
 }
 
+/// Every block entity model, reshaped by a pack or vanilla's, and the atlas names of the
+/// pack's textures by model ([`PackFormats::block_entity_models`]).
+pub type Reshaped = (
+    std::collections::HashMap<&'static str, crate::block_entity_render::ModelPart>,
+    std::collections::HashMap<&'static str, String>,
+);
+
 /// No format beyond vanilla's.
 struct Vanilla;
 

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

@@ -12,7 +12,7 @@ use crate::{
     text::Text,
     ui,
 };
-use horizon_polytone::pack::{ConfigKind, ConfigValue, Configs};
+use horizon_pack_options::{ConfigKind, ConfigValue, Configs};
 
 /// What a click asks of the options screen.
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
@@ -481,17 +481,36 @@ impl PackOptionsUi {
 mod tests {
     use super::*;
 
+    use horizon_pack_options::ConfigEntry;
+
+    fn slider(default: f64) -> ConfigEntry {
+        let kind = ConfigKind::Number {
+            min: 0.0,
+            max: 1.0,
+            step: 0.1,
+        };
+        ConfigEntry::new(kind, ConfigValue::Number(default))
+    }
+
+    fn in_section(entry: ConfigEntry, section: &str, order: i64) -> ConfigEntry {
+        ConfigEntry {
+            section: Some(section.into()),
+            section_order: Some(order),
+            ..entry
+        }
+    }
+
     fn configs() -> Configs {
         let mut c = Configs::default();
-        c.add_entry(
-            "p:fog".into(),
-            &serde_json::json!({"default_value": 0.5, "section": "sky", "section_order": 2}),
-        );
-        c.add_entry("p:rain".into(), &serde_json::json!({"default_value": "drops", "allowed_values": ["drops", "streaks"], "section": "weather", "section_order": 1}));
-        c.add_entry(
-            "p:birds".into(),
-            &serde_json::json!({"default_value": true}),
+        c.insert("p:fog".into(), in_section(slider(0.5), "sky", 2));
+        let allowed = vec!["drops".into(), "streaks".into()];
+        let rain = ConfigEntry::new(
+            ConfigKind::Text { allowed },
+            ConfigValue::Text("drops".into()),
         );
+        c.insert("p:rain".into(), in_section(rain, "weather", 1));
+        let birds = ConfigEntry::new(ConfigKind::Bool, ConfigValue::Bool(true));
+        c.insert("p:birds".into(), birds);
         c
     }
 
@@ -537,9 +556,16 @@ mod tests {
     #[test]
     fn the_presets_row_cycles_the_pack_wide_presets_and_shows_custom_otherwise() {
         let mut c = Configs::default();
-        let entry = |default: f64, fast: f64, pretty: f64| serde_json::json!({"default_value": default, "presets": {"fast": fast, "pretty": pretty}});
-        c.add_entry("p:fog".into(), &entry(0.5, 0.0, 1.0));
-        c.add_entry("p:dust".into(), &entry(0.5, 0.0, 0.8));
+        let entry = |fast: f64, pretty: f64| ConfigEntry {
+            presets: [
+                ("fast".into(), ConfigValue::Number(fast)),
+                ("pretty".into(), ConfigValue::Number(pretty)),
+            ]
+            .into(),
+            ..slider(0.5)
+        };
+        c.insert("p:fog".into(), entry(0.0, 1.0));
+        c.insert("p:dust".into(), entry(0.0, 0.8));
         let mut ui = PackOptionsUi::open(c);
         // The defaults are no preset.
         assert_eq!(ui.current_preset(), None);

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

@@ -38,7 +38,7 @@ pub struct Pack {
     /// Polytone `polytone_condition` turns on.
     pub overlays: Vec<String>,
     /// The values of the pack's Polytone config entries.
-    pub polytone_configs: horizon_polytone::pack::Configs,
+    pub polytone_configs: Configs,
     /// `filter.block` entries (namespace and path patterns) hiding resources
     /// of the packs below this one.
     pub filter: Vec<Filter>,
@@ -419,12 +419,13 @@ fn overlay_applies(entry: &serde_json::Value) -> bool {
         _ => false,
     }
 }
-fn overlays_of(meta: &serde_json::Value, configs: &horizon_polytone::pack::Configs) -> Vec<String> {
+fn overlays_of(meta: &serde_json::Value, configs: &Configs) -> Vec<String> {
+    let formats = crate::pack_hooks::formats();
     meta["overlays"]["entries"]
         .as_array()
         .into_iter()
         .flatten()
-        .filter(|e| horizon_polytone::pack::overlay_active(e, configs, overlay_applies(e)))
+        .filter(|e| formats.overlay_active(e, configs, overlay_applies(e)))
         .filter_map(|e| e["directory"].as_str().map(str::to_owned))
         // OverlayMetadataSection's DIR_VALIDATOR: one folder of the pack, `[-_a-zA-Z0-9.]+`.
         .filter(|d| {
@@ -471,57 +472,12 @@ pub(crate) fn parse_meta(bytes: &[u8]) -> Option<serde_json::Value> {
         .next()?
         .ok()
 }
-/// A pack's Polytone config entries (`assets/<namespace>/polytone/config_entries/<name>.json`,
-/// in the pack's base, not its overlays) at their default values.
-pub fn polytone_configs(source: &Source) -> horizon_polytone::pack::Configs {
-    let mut configs = horizon_polytone::pack::Configs::default();
-    let id_of = |name: &str| -> Option<String> {
-        let rest = name.strip_prefix("assets/")?;
-        let (namespace, rest) = rest.split_once('/')?;
-        let entry = rest
-            .strip_prefix("polytone/config_entries/")?
-            .strip_suffix(".json")?;
-        Some(format!("{namespace}:{entry}"))
-    };
-    match source {
-        Source::Dir(d) => {
-            let Ok(namespaces) = fs::read_dir(d.join("assets")) else {
-                return configs;
-            };
-            for namespace in namespaces.flatten() {
-                let folder = namespace.path().join("polytone/config_entries");
-                for file in fs::read_dir(&folder).into_iter().flatten().flatten() {
-                    let name = format!(
-                        "assets/{}/polytone/config_entries/{}",
-                        namespace.file_name().to_string_lossy(),
-                        file.file_name().to_string_lossy()
-                    );
-                    if let (Some(id), Ok(bytes)) = (id_of(&name), fs::read(file.path()))
-                        && let Ok(json) = serde_json::from_slice(&bytes)
-                    {
-                        configs.add_entry(id, &json);
-                    }
-                }
-            }
-        }
-        Source::Zip(z) => {
-            let Ok(zip) = Zip::open(z) else {
-                return configs;
-            };
-            let names: Vec<String> = zip
-                .names()
-                .filter(|n| id_of(n).is_some())
-                .map(str::to_owned)
-                .collect();
-            for name in names {
-                if let (Some(id), Ok(bytes)) = (id_of(&name), zip.read(&name))
-                    && let Ok(json) = serde_json::from_slice(&bytes)
-                {
-                    configs.add_entry(id, &json);
-                }
-            }
-        }
-    }
+/// A pack's own options (Polytone's config entries, in the pack's base, not its overlays) at
+/// the values the player chose, else their defaults.
+pub fn polytone_configs(source: &Source) -> Configs {
+    let mut configs = crate::pack_hooks::formats()
+        .pack_options(source)
+        .unwrap_or_default();
     for (id, value) in polytone_choices() {
         if configs.entries().contains_key(&id) {
             configs.set(&id, value);
@@ -530,15 +486,15 @@ pub fn polytone_configs(source: &Source) -> horizon_polytone::pack::Configs {
     configs
 }
 
-/// A pack's Polytone config entries and one's value, for the game's Pack Options.
-pub use horizon_polytone::pack::{ConfigValue, Configs};
+/// A pack's options and one's value, for the game's Pack Options.
+pub use horizon_pack_options::{ConfigValue, Configs};
 
 /// The player's Polytone config choices (#11486): what they changed from the packs' defaults,
 /// by entry id, for every pack. `polytone_configs` lays them over each pack's defaults.
-static POLYTONE_CHOICES: std::sync::RwLock<BTreeMap<String, horizon_polytone::pack::ConfigValue>> =
+static POLYTONE_CHOICES: std::sync::RwLock<BTreeMap<String, ConfigValue>> =
     std::sync::RwLock::new(BTreeMap::new());
 
-pub fn polytone_choices() -> BTreeMap<String, horizon_polytone::pack::ConfigValue> {
+pub fn polytone_choices() -> BTreeMap<String, ConfigValue> {
     POLYTONE_CHOICES
         .read()
         .map(|c| c.clone())
@@ -546,7 +502,7 @@ pub fn polytone_choices() -> BTreeMap<String, horizon_polytone::pack::ConfigValu
 }
 
 /// Replaces the player's Polytone config choices (packs read them when they load again).
-pub fn set_polytone_choices(choices: BTreeMap<String, horizon_polytone::pack::ConfigValue>) {
+pub fn set_polytone_choices(choices: BTreeMap<String, ConfigValue>) {
     if let Ok(mut c) = POLYTONE_CHOICES.write() {
         *c = choices;
     }
@@ -558,8 +514,7 @@ pub fn polytone_choices_file() -> std::path::PathBuf {
 }
 
 /// Reads the choices from `path` (none when it is missing or broken).
-pub fn load_polytone_choices(path: &Path) -> BTreeMap<String, horizon_polytone::pack::ConfigValue> {
-    use horizon_polytone::pack::ConfigValue;
+pub fn load_polytone_choices(path: &Path) -> BTreeMap<String, ConfigValue> {
     let Ok(bytes) = fs::read(path) else {
         return BTreeMap::new();
     };
@@ -583,9 +538,8 @@ pub fn load_polytone_choices(path: &Path) -> BTreeMap<String, horizon_polytone::
 /// Writes the choices to `path`.
 pub fn save_polytone_choices(
     path: &Path,
-    choices: &BTreeMap<String, horizon_polytone::pack::ConfigValue>,
+    choices: &BTreeMap<String, ConfigValue>,
 ) -> std::io::Result<()> {
-    use horizon_polytone::pack::ConfigValue;
     let map: serde_json::Map<String, serde_json::Value> = choices
         .iter()
         .map(|(id, v)| {
@@ -856,7 +810,8 @@ fn build_overlay_uncached(
                     packs
                         .get(*owner)
                         .and_then(|p| {
-                            horizon_polytone::pack::sounds_without_unmet(&b, &p.polytone_configs)
+                            crate::pack_hooks::formats()
+                                .sounds_without_unmet(&b, &p.polytone_configs)
                         })
                         .unwrap_or(b),
                 ),
@@ -1606,6 +1561,7 @@ mod tests {
     }
     #[test]
     fn a_sound_entry_whose_polytone_condition_fails_is_left_out() {
+        crate::pack_formats::install();
         let base =
             std::env::temp_dir().join(format!("horizon-packs-sound-cond-{}", std::process::id()));
         let _ = fs::remove_dir_all(&base);
@@ -2121,6 +2077,7 @@ mod tests {
     }
     #[test]
     fn polytone_conditions_turn_overlays_on_from_the_packs_configs() {
+        crate::pack_formats::install();
         let dir =
             std::env::temp_dir().join(format!("horizon-packs-polytone-{}", std::process::id()));
         let _ = fs::remove_dir_all(&dir);

crates/horizon-client-render/src/particles/polytone.rs

@@ -796,7 +796,7 @@ impl Host for Ctx<'_, '_> {
                 .registry
                 .configs
                 .get(id)
-                .map(horizon_polytone::pack::ConfigValue::to_value)
+                .map(horizon_polytone::pack::config_value)
                 .ok_or_else(|| format!("no config {id}")),
             _ => Err(format!("{name} is not available here")),
         }

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

@@ -7,7 +7,10 @@
 //! sections are immutable behind `Arc` and edited through `Arc::make_mut`, so
 //! a weak reference tells an edited or replaced section from the one the list
 //! was built from (see `random_tick_sections`), without keeping its blocks.
-use crate::{chunk::Section, fast_hash::FxHashMap};
+use crate::{
+    chunk::{Chunk, Section},
+    fast_hash::FxHashMap,
+};
 use std::sync::{Arc, Mutex, Weak};
 
 /// A section's POIs: the block index in the section (`y << 8 | z << 4 | x`)
@@ -18,13 +21,16 @@ struct Cached<T> {
     section: Weak<Section>,
     pois: SectionPois<T>,
 }
-/// Cached POI lists by section, `(chunk x, section index, chunk z)`.
+/// Cached POI lists by chunk column `(chunk x, chunk z)`, each by section
+/// index: a search through a column looks it up once.
 pub struct PoiSections<T> {
     sections: Mutex<Lists<T>>,
 }
 struct Lists<T> {
-    by_section: FxHashMap<(i32, i32, i32), Cached<T>>,
-    /// Size above which lists of sections no longer resident are dropped.
+    by_column: FxHashMap<(i32, i32), Vec<Option<Cached<T>>>>,
+    /// How many section lists are kept, and the count above which the lists
+    /// of sections no longer resident are dropped.
+    len: usize,
     prune_at: usize,
 }
 const MIN_PRUNE: usize = 4096;
@@ -32,27 +38,61 @@ impl<T> Default for PoiSections<T> {
     fn default() -> Self {
         Self {
             sections: Mutex::new(Lists {
-                by_section: FxHashMap::default(),
+                by_column: FxHashMap::default(),
+                len: 0,
                 prune_at: MIN_PRUNE,
             }),
         }
     }
 }
-impl<T: Copy> PoiSections<T> {
-    /// The POIs of `section`, whose block states `kind` classifies. `kind`
-    /// must give the same answer for a state on every call.
-    pub fn get(
-        &self,
-        key: (i32, i32, i32),
-        section: &Arc<Section>,
-        mut kind: impl FnMut(u32) -> Option<T>,
-    ) -> SectionPois<T> {
-        let mut lists = self.sections.lock().unwrap_or_else(|e| e.into_inner());
-        if let Some(cached) = lists.by_section.get(&key)
-            && cached.section.as_ptr() == Arc::as_ptr(section)
-        {
-            return cached.pois.clone();
+impl<T: Copy> Lists<T> {
+    /// The column's lists, for sections up to `last`, after dropping the
+    /// lists of sections no longer resident if there are too many.
+    fn column(
+        &mut self,
+        column: (i32, i32),
+        last: usize,
+    ) -> (&mut [Option<Cached<T>>], &mut usize) {
+        if self.len >= self.prune_at {
+            self.prune();
         }
+        let lists = self.by_column.entry(column).or_default();
+        if lists.len() <= last {
+            lists.resize_with(last + 1, || None);
+        }
+        (lists, &mut self.len)
+    }
+
+    /// Drops the lists of sections no longer resident.
+    fn prune(&mut self) {
+        let mut len = 0;
+        self.by_column.retain(|_, lists| {
+            for c in lists.iter_mut() {
+                if c.as_ref().is_some_and(|c| c.section.strong_count() == 0) {
+                    *c = None;
+                }
+            }
+            let kept = lists.iter().filter(|c| c.is_some()).count();
+            len += kept;
+            kept > 0
+        });
+        self.len = len;
+        self.prune_at = (len * 2).max(MIN_PRUNE);
+    }
+}
+
+/// The POIs of `section` from `slot`, listed again (and kept there) unless
+/// `slot` was listed from this very section; `len` counts the slots filled.
+fn list<'a, T: Copy>(
+    slot: &'a mut Option<Cached<T>>,
+    len: &mut usize,
+    section: &Arc<Section>,
+    kind: &mut impl FnMut(u32) -> Option<T>,
+) -> &'a SectionPois<T> {
+    let fresh = slot
+        .as_ref()
+        .is_some_and(|c| c.section.as_ptr() == Arc::as_ptr(section));
+    if !fresh {
         let pois: SectionPois<T> = if section.blocks.maybe_has(|v| kind(v).is_some()) {
             let mut states = [0u32; 4096];
             section.unpack(&mut states);
@@ -64,18 +104,56 @@ impl<T: Copy> PoiSections<T> {
         } else {
             Arc::from([])
         };
-        if lists.by_section.len() >= lists.prune_at {
-            lists.by_section.retain(|_, c| c.section.strong_count() > 0);
-            lists.prune_at = (lists.by_section.len() * 2).max(MIN_PRUNE);
+        *len += usize::from(slot.is_none());
+        *slot = Some(Cached {
+            section: Arc::downgrade(section),
+            pois,
+        });
+    }
+    &slot.as_ref().expect("just listed").pois
+}
+
+impl<T: Copy> PoiSections<T> {
+    /// The POIs of `section`, the `key.1`-th section of the column
+    /// `(key.0, key.2)`, whose block states `kind` classifies. `kind` must give
+    /// the same answer for a state on every call.
+    pub fn get(
+        &self,
+        key: (i32, i32, i32),
+        section: &Arc<Section>,
+        mut kind: impl FnMut(u32) -> Option<T>,
+    ) -> SectionPois<T> {
+        let mut lists = self.sections.lock().unwrap_or_else(|e| e.into_inner());
+        let s = usize::try_from(key.1).expect("a section index");
+        let (column, len) = lists.column((key.0, key.2), s);
+        list(&mut column[s], len, section, &mut kind).clone()
+    }
+
+    /// The POIs of `chunk` from block Y `y0` to `y1`, its first section at
+    /// `min_y`, as [`Self::get`] gives them: each section that has any, with
+    /// the Y of its lowest blocks, in order, put in `out`. One lookup of the
+    /// column.
+    pub fn column(
+        &self,
+        chunk: &Chunk,
+        min_y: i32,
+        (y0, y1): (i32, i32),
+        mut kind: impl FnMut(u32) -> Option<T>,
+        out: &mut Vec<(i32, SectionPois<T>)>,
+    ) {
+        out.clear();
+        let (first, last) = ((y0 - min_y) >> 4, (y1 - min_y) >> 4);
+        if first > last {
+            return;
+        }
+        let mut lists = self.sections.lock().unwrap_or_else(|e| e.into_inner());
+        let (slots, len) = lists.column((chunk.x, chunk.z), last as usize);
+        for s in first as usize..=last as usize {
+            let pois = list(&mut slots[s], len, &chunk.sections[s], &mut kind);
+            if !pois.is_empty() {
+                out.push((min_y + s as i32 * 16, pois.clone()));
+            }
         }
-        lists.by_section.insert(
-            key,
-            Cached {
-                section: Arc::downgrade(section),
-                pois: pois.clone(),
-            },
-        );
-        pois
     }
 }
 
@@ -143,6 +221,48 @@ mod tests {
         assert!(index.get((0, 0, 0), &chunk.sections[0], kind).is_empty());
     }
 
+    /// A column gives each section's list as `get` does, the sections
+    /// without any left out, and keeps them until a section changes.
+    #[test]
+    fn a_column_gives_what_each_section_gives() {
+        let index = PoiSections::<u8>::default();
+        let kind = |v: u32| (v == 5).then_some(5);
+        let mut chunk = Arc::new(Chunk::empty(2, -3));
+        for (x, y, z) in [(1, MIN_Y + 2, 3), (4, MIN_Y + 40, 0), (0, MIN_Y + 41, 15)] {
+            Arc::make_mut(&mut chunk).set(x, y, z, 5);
+        }
+        let mut out = Vec::new();
+        index.column(&chunk, MIN_Y, (MIN_Y, MIN_Y + 63), kind, &mut out);
+        let bases: Vec<i32> = out.iter().map(|(base, _)| *base).collect();
+        assert_eq!(bases, [MIN_Y, MIN_Y + 32]);
+        for (base, pois) in &out {
+            let s = (base - MIN_Y) / 16;
+            let one = index.get((2, s, -3), &chunk.sections[s as usize], kind);
+            assert!(Arc::ptr_eq(pois, &one));
+        }
+        // Kept: no rescan.
+        index.column(
+            &chunk,
+            MIN_Y,
+            (MIN_Y, MIN_Y + 63),
+            |_| panic!("rescanned"),
+            &mut out,
+        );
+        assert_eq!(out.len(), 2);
+        // An edit lists that section again.
+        Arc::make_mut(&mut chunk).set(4, MIN_Y + 40, 0, 1);
+        let mut rescans = 0;
+        let counted = |v: u32| {
+            rescans += 1;
+            kind(v)
+        };
+        index.column(&chunk, MIN_Y, (MIN_Y + 20, MIN_Y + 63), counted, &mut out);
+        assert!(rescans > 0);
+        assert_eq!(out.len(), 1);
+        assert_eq!(out[0].0, MIN_Y + 32);
+        assert_eq!(&*out[0].1, &[(9 << 8 | 15 << 4, 5)]);
+    }
+
     #[test]
     fn unloaded_sections_are_dropped() {
         let index = PoiSections::<u8>::default();
@@ -153,7 +273,7 @@ mod tests {
             index.get((1, i, 0), &Arc::new(Section::default()), kind);
         }
         let lists = index.sections.lock().unwrap();
-        assert!(lists.by_section.len() <= 2);
-        assert!(lists.by_section.contains_key(&(0, 0, 0)));
+        assert!(lists.len <= 2);
+        assert!(lists.by_column[&(0, 0)][0].is_some());
     }
 }

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

@@ -237,17 +237,17 @@ impl<P: Copy, S: Copy> Lines<P, S> {
 pub(crate) fn backdrop(batch: &mut HudBatch, atlas: &HudAtlas, in_world: bool) {
     let (w, h) = (batch.width, batch.height);
     ui::menu_background(batch, atlas, 0.0, 0.0, w, h, in_world);
-    style::fill(batch, atlas, [0.0, 0.0, w, h], style::VEIL);
+    style::fill(batch, atlas, [0.0, 0.0, w, h], style::veil());
 }
 
 /// The mark and the screen's name over the search field.
 pub(crate) fn mark(batch: &mut HudBatch, atlas: &HudAtlas, cols: &Columns, title: &str) {
     let (x, y) = (cols.side_x, cols.side_y);
-    style::fill(batch, atlas, [x, y + 2.0, 6.0, 6.0], style::ACCENT);
+    style::fill(batch, atlas, [x, y + 2.0, 6.0, 6.0], style::accent());
     let horizon = Text::literal("Horizon");
     batch.text_styled(atlas, &horizon, x + 10.0, y, style::WHITE, true);
     let title = Text::literal(title);
-    batch.text_styled(atlas, &title, x, y + 10.0, style::MUTED, true);
+    batch.text_styled(atlas, &title, x, y + 10.0, style::muted(), true);
 }
 
 /// A page in the page list: the open page on a plate with the accent's bar beside it, the
@@ -273,13 +273,13 @@ pub(crate) fn page_tab(
         crate::widgets::target_as(rect, crate::widgets::Kind::Tab(open));
     }
     if open {
-        style::fill(batch, atlas, rect, style::OPEN);
-        style::fill(batch, atlas, [px, py, 2.0, ph], style::ACCENT);
+        style::fill(batch, atlas, rect, style::open());
+        style::fill(batch, atlas, [px, py, 2.0, ph], style::accent());
     }
     let color = match (open || hover, has) {
         (true, _) => style::WHITE,
-        (false, true) => style::SOFT,
-        (false, false) => style::MUTED,
+        (false, true) => style::soft(),
+        (false, false) => style::muted(),
     };
     let ty = py + ((ph - 8.0) / 2.0).floor();
     let name = Text::literal(style::fit(atlas, name, pw - 12.0));
@@ -312,12 +312,12 @@ pub(crate) fn search_field(
     search.draw(batch, atlas, None);
     if search.value.is_empty() && !focused {
         let hint = Text::literal(search.message.clone());
-        batch.text_styled(atlas, &hint, x + 5.0, search.y, style::MUTED, true);
+        batch.text_styled(atlas, &hint, x + 5.0, search.y, style::muted(), true);
     }
     if !search.value.is_empty() {
         let hover = ui::hovered(cursor, clear[0], clear[1], clear[2], clear[3]);
         crate::widgets::widget_cursor(hover, true);
-        let color = if hover { style::WHITE } else { style::MUTED };
+        let color = if hover { style::WHITE } else { style::muted() };
         let cy = y + ((h - 8.0) / 2.0).floor();
         ui::centered_text(
             batch,
@@ -344,7 +344,7 @@ pub(crate) fn plate(batch: &mut HudBatch, atlas: &HudAtlas, cols: &Columns, head
         batch,
         atlas,
         [px + 8.0, py + 24.0, pw - 16.0, 1.0],
-        style::HEAD_RULE,
+        style::head_rule(),
     );
 }
 
@@ -383,9 +383,9 @@ pub(crate) fn list<P: Copy, S: Copy>(
         }
         let Some(setting) = line.setting else {
             let (name, color, dy) = match line.group {
-                Some(("", _)) => (page_name(line.page), style::MUTED, 3.0),
-                Some((name, _)) => (lang::get(name), style::MUTED, 3.0),
-                None => (page_name(line.page), style::ACCENT, 4.0),
+                Some(("", _)) => (page_name(line.page), style::muted(), 3.0),
+                Some((name, _)) => (lang::get(name), style::muted(), 3.0),
+                None => (page_name(line.page), style::accent(), 4.0),
             };
             let name = Text::literal(name);
             batch.text_styled(atlas, &name, cols.list_x + 2.0, y + dy, color, true);
@@ -393,7 +393,7 @@ pub(crate) fn list<P: Copy, S: Copy>(
         };
         if !after_name {
             let rule = [cols.list_x + 8.0, y, cols.list_w - 16.0, 1.0];
-            style::fill(batch, atlas, rule, style::ROW_RULE);
+            style::fill(batch, atlas, rule, style::row_rule());
         }
         row(batch, setting, y);
     }
@@ -404,7 +404,7 @@ pub(crate) fn list<P: Copy, S: Copy>(
             &none,
             cols.list_x + 2.0,
             cols.top + 4.0,
-            style::MUTED,
+            style::muted(),
             true,
         );
     }
@@ -499,7 +499,7 @@ pub(crate) fn row(batch: &mut HudBatch, atlas: &HudAtlas, cols: &Columns, y: f32
     let active = live && (hover || focused || held);
     if active {
         let lit = [rect[0] + 2.0, y + 1.0, rect[2] - 4.0, style::ROW - 2.0];
-        style::fill(batch, atlas, lit, style::HOVER);
+        style::fill(batch, atlas, lit, style::hover());
     }
     crate::widgets::widget_cursor(hover, live);
     // The control socket's widget tree, the narrator and a controller's focus.
@@ -523,8 +523,8 @@ pub(crate) fn row(batch: &mut HudBatch, atlas: &HudAtlas, cols: &Columns, y: f32
     if live {
         crate::widgets::target_as(rect, kind);
     }
-    let color = if live { style::WHITE } else { style::MUTED };
-    let soft = if live { style::SOFT } else { style::MUTED };
+    let color = if live { style::WHITE } else { style::muted() };
+    let soft = if live { style::soft() } else { style::muted() };
     let ty = y + ((style::ROW - 8.0) / 2.0).floor();
     let lit = live && (hover || held);
     let left = rect[0] + style::INSET;
@@ -611,7 +611,7 @@ fn lit(batch: &mut HudBatch, atlas: &HudAtlas, [x, y, w, _]: [f32; 4]) {
         batch,
         atlas,
         [x + 2.0, y + 1.0, w - 4.0, style::ROW - 2.0],
-        style::HOVER,
+        style::hover(),
     );
 }
 
@@ -644,7 +644,7 @@ fn read_row(
     let room = rect[2] - 2.0 * style::INSET - name_w - 8.0;
     let value = style::fit(atlas, value, room);
     let vx = rect[0] + rect[2] - style::INSET - atlas.font.width(&value);
-    batch.text_styled(atlas, &Text::literal(value), vx, ty, style::SOFT, true);
+    batch.text_styled(atlas, &Text::literal(value), vx, ty, style::soft(), true);
     if focused {
         style::ring(
             batch,
@@ -749,7 +749,7 @@ fn pad_row(batch: &mut HudBatch, atlas: &HudAtlas, cols: &Columns, y: f32, view:
         batch.text_styled(atlas, &yellow(close), right.ceil(), ty, style::WHITE, true);
     }
     let left = rect[0] + style::INSET;
-    let color = if live { style::WHITE } else { style::MUTED };
+    let color = if live { style::WHITE } else { style::muted() };
     let shown = Text::literal(style::fit(atlas, name, chip[0] - 6.0 - left));
     batch.text_styled(atlas, &shown, left, ty, color, true);
     if focused {
@@ -799,7 +799,7 @@ fn side_lines(
         ];
         crate::widgets::record(line, rect, false);
         let shown = Text::literal(style::fit(atlas, line, rect[2]));
-        batch.text_styled(atlas, &shown, rect[0], rect[1], style::MUTED, true);
+        batch.text_styled(atlas, &shown, rect[0], rect[1], style::muted(), true);
     }
 }
 /// A line under the page list: its inset, and its height.
@@ -881,7 +881,7 @@ fn heading(batch: &mut HudBatch, atlas: &HudAtlas, text: &str, [x, y, w, _]: [f3
     let rect = [x + SIDE_INSET, y + HEADING_Y, w - 2.0 * SIDE_INSET, 8.0];
     crate::widgets::record(text, rect, false);
     let shown = Text::literal(style::fit(atlas, text, rect[2]));
-    batch.text_styled(atlas, &shown, rect[0], rect[1], style::MUTED, true);
+    batch.text_styled(atlas, &shown, rect[0], rect[1], style::muted(), true);
 }
 
 /// Vanilla's scroller, inside the panel's right edge, sized as `ui::Scroll` drags it.
@@ -1896,8 +1896,8 @@ impl<S: Screen> Shell<S> {
             // The row's page is open: lit as the list's open page is.
             if list.lit == Some(*shown) {
                 let row @ [x, y, _, h] = strip.area;
-                style::fill(batch, atlas, row, style::OPEN);
-                style::fill(batch, atlas, [x, y, 2.0, h], style::ACCENT);
+                style::fill(batch, atlas, row, style::open());
+                style::fill(batch, atlas, [x, y, 2.0, h], style::accent());
             }
             tabs::draw(batch, atlas, strip);
         }
@@ -2134,7 +2134,14 @@ impl<S: Screen> Shell<S> {
             crate::widgets::narratable(|| crate::widgets::Narratable::text(row.name.clone(), rect));
             let ty = y + ((style::ROW - 8.0) / 2.0).floor();
             let name = Text::literal(style::fit(atlas, &row.name, rect[2] - 2.0 * style::INSET));
-            batch.text_styled(atlas, &name, rect[0] + style::INSET, ty, style::MUTED, true);
+            batch.text_styled(
+                atlas,
+                &name,
+                rect[0] + style::INSET,
+                ty,
+                style::muted(),
+                true,
+            );
             return;
         }
         let over = |[x, y, w, h]: [f32; 4]| pointer.is_some_and(|at| ui::hovered(at, x, y, w, h));
@@ -2240,7 +2247,7 @@ impl<S: Screen> Shell<S> {
         // Labelled for the widget tree: what the strip says is what a test or an agent reads.
         crate::widgets::record(about, cols.dock, false);
         let color = if why.is_some() {
-            style::MUTED
+            style::muted()
         } else {
             style::GREY
         };

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

@@ -304,19 +304,19 @@ impl StudioUi {
 
                 // Card background & highlight
                 if is_selected {
-                    style::fill(batch, atlas, rect, style::OPEN);
+                    style::fill(batch, atlas, rect, style::open());
                 } else if is_hovered {
-                    style::fill(batch, atlas, rect, style::HOVER);
+                    style::fill(batch, atlas, rect, style::hover());
                 } else {
                     style::well(batch, atlas, rect);
                 }
 
                 let border_color = if is_selected {
-                    style::ACCENT
+                    style::accent()
                 } else if is_hovered {
                     style::WHITE
                 } else {
-                    style::ROW_RULE
+                    style::row_rule()
                 };
                 style::ring(batch, atlas, rect, border_color);
 

crates/horizon-client/Cargo.toml

@@ -119,14 +119,11 @@ audio = ["horizon-client-render/audio", "horizon-client-lib/audio"]
 controllers = ["horizon-client-lib/controllers", "dep:gilrs", "dep:horizon-dualsense", "horizon-client-input/controllers"]
 # Horizon's own extras over the vanilla game, for a fork that wants them out (docs/forking.md):
 # cosmetics and emotes, the "Horizon player" presence, the official server added to
-# the server list, the Horizon Settings and Mods pages, Discord and Play with Friends, and ray
-# tracing on request (`HORIZON_RAY_TRACING=1`). Players always get them; there is no switch. `grep -rn horizon-extras crates/` lists
+# the server list, the Horizon Settings and Mods pages and Play with Friends, and ray tracing on
+# request (`HORIZON_RAY_TRACING=1`). Players always get them; there is no switch. `grep -rn horizon-extras crates/` lists
 # every place it gates. Without it (`--no-default-features --features audio,controllers`) the
 # client is best effort: CI builds only the default.
-horizon-extras = ["horizon-client-lib/horizon-extras", "horizon-client-render/horizon-extras", "discord", "friends"]
-# Online extras a server or a port can leave out; the server build has none of them. "Playing Horizon"
-# on Discord (game/discord.rs).
-discord = ["horizon-client-lib/discord"]
+horizon-extras = ["horizon-client-render/horizon-extras", "friends"]
 # Play with Friends: sharing a world behind an invite code (game/friends.rs). Joining one is
 # horizon-friends' `game` side, which horizon-official registers (`horizon_hooks::tunnel`).
 friends = ["dep:horizon-friends"]

crates/horizon-client/examples/model_library_bench.rs

@@ -50,6 +50,8 @@ unsafe impl GlobalAlloc for CountingAllocator {
 static ALLOCATOR: CountingAllocator = CountingAllocator;
 
 fn main() -> horizon_client::Result<()> {
+    // The pack formats the game installs at startup, so their loading is measured too.
+    horizon_client::pack_formats::install();
     let root = std::env::args()
         .nth(1)
         .ok_or("usage: model_library_bench ROOT [--parity]")?;

crates/horizon-client/src/client_lib.rs

@@ -14,19 +14,20 @@ pub use horizon_client_render::{
     block_entities, block_entity_anim, block_entity_render, block_sprites, block_states, bluemap,
     bluemap_detect, border_render, breaking, brewing, camera, chat, chunk, chunk_map, cit,
     cit_armor, cit_assets, cit_glint, client_resources, clouds, collisions, command_block,
-    containers, controller_ui, crash, custom_sky, datapack, dynamic_light, effects, environment,
-    extras, fast_hash, fluid_render, fog, font, gfx, graphics, graphics_style, graphics_ui,
-    hdr_calibration, hud, hud_kit, hud_layout, hud_overlays, inventory_effects, java_text,
-    jigsaw_block, json_folder, level_loading, light, lod, logging, menu_blur, mesher, minimap,
-    mipmap, mod_browser, mod_list, model_library, models, multiline_edit, native_emissive,
-    options_file, options_fixes, options_ui, overlay, pack_browser, pack_formats, pack_hooks,
-    pack_palette, pack_screen, packs, pad_cursor, pad_glyph, par, particles, poi_sections,
-    polytone_creative_tabs, polytone_post, post_chain, potent_sulfur, preedit, providers, pvp,
-    pvp_hud, random_source, screen_draw, screen_effects, sculk, section_mask, server_terrain,
-    settings, shader_options, shader_pack_list, signs, skins, social, sound_engine, sound_events,
-    sound_preview, spans, split_layout, split_map, split_profiles, sprites, streaming,
-    structure_block, tab_list, terrain_model, test_block, test_instance_block, testgen,
-    title_edition, trims, ui, vault, weather, widgets, world, worldborder, zip,
+    containers, controller_ui, crash, custom_sky, datapack, dynamic_light, effects,
+    entity_textures, environment, extras, fast_hash, fluid_render, fog, font, gfx, graphics,
+    graphics_style, graphics_ui, hdr_calibration, hud, hud_kit, hud_layout, hud_overlays,
+    inventory_effects, java_text, jigsaw_block, json_folder, level_loading, light, lod, logging,
+    menu_blur, menu_style, mesher, minimap, mipmap, mod_browser, mod_list, model_library, models,
+    multiline_edit, native_emissive, options_file, options_fixes, options_ui, overlay,
+    pack_browser, pack_formats, pack_hooks, pack_palette, pack_screen, packs, pad_cursor,
+    pad_glyph, par, particles, poi_sections, polytone_creative_tabs, polytone_post, post_chain,
+    potent_sulfur, preedit, providers, pvp, pvp_hud, random_source, screen_draw, screen_effects,
+    sculk, section_mask, server_terrain, settings, shader_options, shader_pack_list, signs, skins,
+    social, sound_engine, sound_events, sound_preview, spans, split_layout, split_map,
+    split_profiles, sprites, streaming, structure_block, tab_list, terrain_model, test_block,
+    test_instance_block, testgen, title_edition, trims, ui, vault, weather, widgets, world,
+    worldborder, zip,
 };
 pub mod attack_strength;
 pub mod attribute_updates;
@@ -58,8 +59,6 @@ pub mod debug_overlay;
 pub mod debugworld;
 pub mod dialog;
 pub mod dialog_screen;
-#[cfg(feature = "discord")]
-pub mod discord_presence;
 pub mod end_crystal;
 pub mod end_gateway;
 pub mod entities;
@@ -91,6 +90,7 @@ pub mod locator_bar;
 pub mod lod_net;
 pub mod menu;
 pub mod merchant;
+pub mod mob_formats;
 pub mod mobs;
 pub mod mod_content;
 pub mod mod_registry;

crates/horizon-client/src/entry.rs

@@ -13,8 +13,10 @@ pub fn main_with(mods: crate::mod_api::Mods) {
         log::warn!("Trait mods already installed; ignoring the second list");
     }
     horizon_threads::configure_allocator();
+    crate::horizon_look::give();
     // OptiFine's and Polytone's pack formats (platform, docs/layers.md), before any pack loads.
     horizon_client::pack_formats::install();
+    horizon_client::mob_formats::install();
     // horizon-extras (docs/forking.md): without the feature, no Horizon Settings or Mods page.
     if !cfg!(feature = "horizon-extras") {
         horizon_client::options_ui::HORIZON_EXTRAS

crates/horizon-client/src/game.rs

@@ -49,6 +49,7 @@ fn pack_files(world_tables: &Option<WorldTables>) -> horizon_world::loot::PackOv
     }
 }
 
+mod activity;
 mod advancements;
 mod advancements_screen;
 mod agent;
@@ -128,8 +129,6 @@ mod decorated_pot;
 mod dedicated;
 mod deflect;
 mod dialogs;
-#[cfg(feature = "discord")]
-mod discord;
 mod dispense_fixture;
 mod dispenser;
 mod dragon;
@@ -1499,7 +1498,7 @@ impl LevelAccess for GameLevel<'_> {
             };
         }
         if let Some(signal) = books::lectern_signal(self.world, pos) {
-            return signal;
+            return signal * i32::from(books::has_book_state(self.registry, state));
         }
         if let Some(signal) =
             machines::shelf_signal(self.world, self.registry, state, pos, direction)
@@ -6717,8 +6716,8 @@ impl Game<'_> {
                 .extend(out.drain(player_start..));
         }
         self.mark_motion(out.len(), 0);
-        // Companions in first person, trails and auras (game/cosmetics/fx.rs).
-        self.cosmetics_fx_geometry(camera, alpha, &mut out);
+        // What crates draw around players: first person, see-through (game/player_hooks.rs).
+        self.players_after_geometry(camera, alpha, &mut out);
         self.mark_entity(out.len(), "minecraft:evoker_fangs");
         self.fangs_geometry(camera, alpha, &mut out);
         self.block_item_display_geometry(camera, alpha, &mut out);
@@ -11253,8 +11252,7 @@ impl Game<'_> {
                     self.heal_hold_latches();
                     // For the hooks above the engine (the "I'm playing" ping): said when it changes.
                     horizon_hooks::engine::published(self.is_published());
-                    #[cfg(feature = "discord")]
-                    self.update_discord_presence();
+                    self.report_activity();
                     let steps = self.clock.advance(elapsed);
                     for _ in 0..steps {
                         let started = Instant::now();
@@ -12529,15 +12527,8 @@ pub fn run_with() -> Result<()> {
     if options.execution_role.is_client() {
         narrator::start(&early_settings);
     }
-    // "Playing Horizon" on Discord: never for a server; an automated run only talks to a test's fake Discord.
-    #[cfg(feature = "discord")]
-    if options.dedicated.is_none() {
-        let automated = options.benchmark.is_some()
-            || options.offscreen
-            || options.frames.is_some()
-            || options.world_frames.is_some();
-        horizon_client::discord_presence::start(early_settings.extras.discord_presence, automated);
-    }
+    // A game window's hooks (Discord's presence): never for a server.
+    activity::client_started(&options, &early_settings);
     // Snapshots of derived tables live in the game folder, never beside the
     // shared resources.
     Behaviours::set_cache_dir(std::env::current_dir()?.join(".horizon-cache"));

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

@@ -0,0 +1,76 @@
+//! What the player is doing, for the hooks above the engine (`Hooks::activity`: the Horizon
+//! layer's Discord presence shows it).
+use super::*;
+use horizon_client::command::args::GameMode;
+use horizon_hooks::{Activity, Client, Dimension, Play};
+
+/// At startup, for a game window (never a dedicated server's): the player's first activity, then
+/// `Hooks::client_started`.
+pub(super) fn client_started(options: &Options, settings: &Settings) {
+    if options.dedicated.is_some() {
+        return;
+    }
+    let automated = options.benchmark.is_some()
+        || options.offscreen
+        || options.frames.is_some()
+        || options.world_frames.is_some();
+    // The Discord switch's state is the first thing the presence hears, so nothing is sent with
+    // it off.
+    horizon_hooks::engine::activity(match settings.extras.discord_presence {
+        true => Activity::Menus,
+        false => Activity::Hidden,
+    });
+    horizon_hooks::engine::client_started(&Client::new(automated));
+}
+
+impl Game<'_> {
+    /// Each frame: only a change reaches the hooks.
+    pub(super) fn report_activity(&self) {
+        // One status per computer: P1's, not a splitscreen player's.
+        if self.options.split_guest {
+            return;
+        }
+        horizon_hooks::engine::activity(self.activity());
+    }
+    fn activity(&self) -> Activity {
+        if !self.settings.extras.discord_presence {
+            return Activity::Hidden;
+        }
+        if self.title.is_some() {
+            return Activity::Menus;
+        }
+        let max = horizon_client::lan::MAX_PLAYERS;
+        let play = if let Some(host) = &self.lan {
+            Play::Hosting {
+                players: 1 + host.hub.guests.len(),
+                max,
+            }
+        } else if let Some(server) = &self.integrated {
+            match (server.published(), &self.remote) {
+                (Some(_), Some(remote)) => Play::Hosting {
+                    players: remote.player_count(),
+                    max,
+                },
+                _ => Play::Singleplayer,
+            }
+        } else if self.remote.is_some() {
+            Play::Multiplayer
+        } else {
+            Play::Singleplayer
+        };
+        Activity::World {
+            play,
+            dimension: match self.dim {
+                Dim::Overworld => Dimension::Overworld,
+                Dim::Nether => Dimension::Nether,
+                Dim::End => Dimension::End,
+            },
+            mode: match self.mode {
+                GameMode::Survival => horizon_hooks::GameMode::Survival,
+                GameMode::Creative => horizon_hooks::GameMode::Creative,
+                GameMode::Adventure => horizon_hooks::GameMode::Adventure,
+                GameMode::Spectator => horizon_hooks::GameMode::Spectator,
+            },
+        }
+    }
+}

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

@@ -1608,6 +1608,16 @@ impl Game<'_> {
         }
     }
 }
+/// `LecternBlock.getAnalogOutputSignal`'s `HAS_BOOK` check.
+pub(super) fn has_book_state(
+    registry: &'static horizon_world::registry::BlockRegistry,
+    state: horizon_world::registry::BlockStateId,
+) -> bool {
+    registry
+        .state(state)
+        .is_some_and(|s| s.properties.get("has_book").is_some_and(|v| v == "true"))
+}
+
 /// `LecternBlockEntity.getRedstoneSignal`.
 pub(super) fn lectern_signal(world: &horizon_client::world::World, pos: BlockPos) -> Option<i32> {
     match world.block_entities.get(&(pos.x, pos.y, pos.z)) {
@@ -1721,6 +1731,7 @@ mod lectern_signal_tests {
         items::ItemStack,
     };
     use horizon_core::position::BlockPos;
+    use horizon_world::level::LevelAccess;
     use horizon_world::registry::BlockStateId;
 
     fn signal(game: &mut super::Game<'_>, book: Option<ItemStack>, page: i32) -> i32 {
@@ -1738,6 +1749,55 @@ mod lectern_signal_tests {
         lectern_signal(&game.world, BlockPos::new(key.0, key.1, key.2)).unwrap()
     }
 
+    /// `LecternBlock.getAnalogOutputSignal` reads the block entity only while
+    /// the state's `HAS_BOOK` is true.
+    #[test]
+    #[ignore = "needs prepared resources in HORIZON_TEST_RESOURCES"]
+    fn a_lectern_without_the_has_book_state_feeds_no_comparator() {
+        let mut game = server_game();
+        let key = (8, 64, 8);
+        let state = game
+            .pack
+            .assets
+            .registry
+            .default_state("minecraft:lectern")
+            .unwrap();
+        game.world.set(key.0, key.1, key.2, state).unwrap();
+        game.world.block_entities.insert(
+            key,
+            BlockEntity::Lectern(Lectern {
+                book: Some(ItemStack::new("minecraft:writable_book", 1)),
+                page: 0,
+            }),
+        );
+        let signal = |game: &mut super::Game<'_>, state| {
+            game.with_level(|_, level, _| {
+                level.block_entity_analog_signal(
+                    BlockPos::new(key.0, key.1, key.2),
+                    state,
+                    horizon_core::geometry::Direction::North,
+                )
+            })
+        };
+        assert_eq!(
+            signal(&mut game, state),
+            0,
+            "the block state says the lectern holds no book"
+        );
+        let registry = game.pack.assets.registry;
+        let mut with_book = registry.state(state).unwrap().clone();
+        with_book
+            .properties
+            .insert("has_book".into(), "true".into());
+        let with_book = registry.id(&with_book).unwrap();
+        game.world.set(key.0, key.1, key.2, with_book).unwrap();
+        assert_eq!(
+            signal(&mut game, with_book),
+            15,
+            "with HAS_BOOK the book's page signal"
+        );
+    }
+
     /// `LecternBlockEntity.getRedstoneSignal`: `floor(page / (pageCount - 1)
     /// * 14) + (hasBook() ? 1 : 0)`. `hasBook()` asks for a book-content
     /// component, so a stack that only sits in the lectern (a non-book item a

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

@@ -21,8 +21,8 @@ use horizon_cosmetics::prefs::{self, Others};
 use horizon_cosmetics::trail::{Budget, Emitter};
 use horizon_cosmetics::{Item, Slot};
 use horizon_hooks::players::{
-    Badge, CameraOverride, CameraView, Frame, Gear, Kind, Mark, NameDecoration, PlayerModel,
-    PlayerModels, SpriteStore, Sprites,
+    Badge, Bone, CameraOverride, CameraView, Frame, Gear, Kind, Look, Mark, Mesh, NameDecoration,
+    PlayerDraw, PlayerModel, PlayerModels, Quad, SpriteStore, Sprites,
 };
 use std::cell::{Cell, RefCell};
 use std::sync::mpsc::{Receiver, channel};
@@ -66,8 +66,8 @@ pub(super) struct Cosmetics {
     /// Items drawn whose texture isn't in the atlas yet.
     uploads: RefCell<Vec<Arc<Item>>>,
     frame: Cell<u32>,
-    /// Kept between players so a frame of avatars allocates none: the wearer's body, an item.
-    poses: RefCell<(Poses, Poses)>,
+    /// Kept between players so a frame of avatars allocates none: a companion or an aura.
+    poses: RefCell<Poses>,
     /// Item files from a folder (`HORIZON_COSMETICS_LOCAL`): mannequins wear them too.
     local: bool,
     /// Companions, trails and auras.
@@ -463,14 +463,45 @@ struct Seat {
     models: Vec<PlayerModel>,
     /// The world is the window's own single-player one (`Frame::solo`).
     solo: bool,
-    /// Name tag badges' sprites, by the item's address: their id (never reused) and the item,
-    /// held so the address isn't reused while it is there.
-    sprites: FxHashMap<usize, (u64, Arc<Item>)>,
+    /// The items the hooks show, by the item's address.
+    items: FxHashMap<usize, Kept>,
     last_sprite: u64,
     /// Sprites drawing missed, put in the atlas next frame.
     wanted: Vec<u64>,
 }
 
+/// An item the hooks show: its sprite's id (never reused) and a mesh per bone it rides, held
+/// with the item so its address isn't reused while it is here.
+struct Kept {
+    sprite: u64,
+    item: Arc<Item>,
+    meshes: Vec<(Bone, Arc<Mesh>)>,
+}
+
+/// The hooks' model of an item's part.
+fn mesh(p: &horizon_cosmetics::Part) -> Mesh {
+    let quads = p.faces.iter().map(|f| Quad::new(f.normal, f.vertices));
+    Mesh::new(
+        p.name.clone(),
+        p.pose,
+        quads.collect(),
+        p.children.iter().map(mesh).collect(),
+    )
+}
+
+/// The hooks' name of a bone.
+fn bone(b: horizon_cosmetics::Bone) -> Bone {
+    use horizon_cosmetics::Bone as B;
+    match b {
+        B::Head => Bone::Head,
+        B::Body => Bone::Body,
+        B::LeftArm => Bone::LeftArm,
+        B::RightArm => Bone::RightArm,
+        B::LeftLeg => Bone::LeftLeg,
+        B::RightLeg => Bone::RightLeg,
+    }
+}
+
 /// What the game tells the hooks before each call, until the settings move here (spec #14091
 /// step 5a) and the player's emote with them (step 4).
 #[derive(Default)]
@@ -539,6 +570,10 @@ impl horizon_hooks::Hooks for Hooks {
     }
 
     /// An emote pulls the camera back: it eases out over the emote's first quarter second.
+    fn player_layers(&self, model: &PlayerModel, draw: &mut dyn PlayerDraw) {
+        service(|s| s.player_layers(model, draw));
+    }
+
     fn camera(&self, own: &CameraView) -> Option<CameraOverride> {
         let start = service(|s| s.said.pull)?;
         let t = ((own.age - start) / 5.0).clamp(0.0, 1.0);
@@ -664,14 +699,7 @@ impl Seat {
         if !(styles || said.marks) {
             return None;
         }
-        let uuid = match m.kind {
-            Kind::Own => own_uuid(m.uuid, self.solo, said.solo, || {
-                horizon_client::auth::current().map(|s| s.uuid)
-            }),
-            Kind::Mannequin if self.local => Some(u128::from(m.id)),
-            Kind::Player => m.uuid,
-            _ => None,
-        }?;
+        let uuid = self.uuid_of(m)?;
         let mut frame = self.client.as_ref()?.frame();
         let mark = (said.marks && frame.horizon(uuid)).then_some(MARK);
         let worn = if styles { frame.worn(uuid) } else { None };
@@ -687,42 +715,135 @@ impl Seat {
         Some(NameDecoration::new(mark, badge, top))
     }
 
-    /// The name tag style in `worn`: its badge's place in the atlas and its line's colour. None
-    /// until the badge is in the atlas (it is put there next frame).
-    fn badge(&mut self, worn: &horizon_cosmetics::Worn, sprites: &dyn Sprites) -> Option<Badge> {
-        let item = worn.iter().find(|i| i.slot == Slot::NameTag)?;
-        let [r, g, b] = item.tag?.line;
+    /// The UUID the service knows `m` by: a player's, or a mannequin's id with local items.
+    fn uuid_of(&self, m: &PlayerModel) -> Option<u128> {
+        match m.kind {
+            Kind::Own => own_uuid(m.uuid, self.solo, self.said.solo, || {
+                horizon_client::auth::current().map(|s| s.uuid)
+            }),
+            Kind::Mannequin if self.local => Some(u128::from(m.id)),
+            Kind::Player => m.uuid,
+            _ => None,
+        }
+    }
+
+    /// `item` as the hooks show it, kept from its first sight.
+    fn kept(&mut self, item: &Arc<Item>) -> &Kept {
         let next = self.last_sprite + 1;
-        let (id, _) = *self
-            .sprites
+        let kept = self
+            .items
             .entry(Arc::as_ptr(item) as usize)
-            .or_insert_with(|| (next, item.clone()));
-        self.last_sprite = self.last_sprite.max(id);
-        let Some([u0, v0, u1, v1]) = sprites.get(id) else {
+            .or_insert_with(|| Kept {
+                sprite: next,
+                item: item.clone(),
+                meshes: item
+                    .roots()
+                    .map(|(b, root)| (bone(b), Arc::new(mesh(root))))
+                    .collect(),
+            });
+        self.last_sprite = self.last_sprite.max(kept.sprite);
+        kept
+    }
+
+    /// Where `item`'s texture is in the atlas (`get` reads the crate's sprites): the top left
+    /// corner of its slot. None until it is there (it is put there next frame).
+    fn uv(&mut self, item: &Arc<Item>, get: impl Fn(u64) -> Option<[f32; 4]>) -> Option<[f32; 4]> {
+        let id = self.kept(item).sprite;
+        let Some([u0, v0, u1, v1]) = get(id) else {
             if !self.wanted.contains(&id) {
                 self.wanted.push(id);
             }
             return None;
         };
-        // The mark sits in the slot's top left corner.
-        let u1 = u0 + (u1 - u0) * item.texture.width as f32 / 64.0;
-        let v1 = v0 + (v1 - v0) * item.texture.height as f32 / 64.0;
-        Some(Badge::new(
-            [u0, v0, u1, v1],
-            u32::from_be_bytes([0, r, g, b]),
-        ))
+        let (w, h) = (
+            item.texture.width as f32 / 64.0,
+            item.texture.height as f32 / 64.0,
+        );
+        Some([u0, v0, u0 + (u1 - u0) * w, v0 + (v1 - v0) * h])
     }
 
-    /// Puts the sprites drawing missed in the atlas; forgets those of items no one wears.
+    /// The name tag style in `worn`: its badge and its line's colour. None until the badge is in
+    /// the atlas.
+    fn badge(&mut self, worn: &horizon_cosmetics::Worn, sprites: &dyn Sprites) -> Option<Badge> {
+        let item = worn.iter().find(|i| i.slot == Slot::NameTag)?;
+        let [r, g, b] = item.tag?.line;
+        let uv = self.uv(item, |id| sprites.get(id))?;
+        Some(Badge::new(uv, u32::from_be_bytes([0, r, g, b])))
+    }
+
+    /// Puts the sprites drawing missed in the atlas; forgets the items no one wears.
     fn put_sprites(&mut self, store: &mut dyn SpriteStore) {
         for id in self.wanted.drain(..) {
-            let item = self.sprites.values().find(|(i, _)| *i == id);
-            if let Some((_, item)) = item.filter(|_| !store.has(id)) {
-                store.put(id, slot_image(item));
+            let kept = self.items.values().find(|k| k.sprite == id);
+            if let Some(kept) = kept.filter(|_| !store.has(id)) {
+                store.put(id, slot_image(&kept.item));
+            }
+        }
+        self.items.retain(|_, k| Arc::strong_count(&k.item) > 1);
+    }
+
+    /// The cosmetics `m` wears, on its bones, and an emote's props (companions, trails and auras
+    /// are still the game's: `cosmetics_geometry`).
+    fn player_layers(&mut self, m: &PlayerModel, draw: &mut dyn PlayerDraw) {
+        if m.invisible {
+            return;
+        }
+        let said = &self.said;
+        let own = m.kind == Kind::Own;
+        let shown = if own { said.mine } else { !said.others_hidden };
+        // "Name tags only": other players' styles beside their names, nothing on their bodies.
+        let bodies = own || said.others_shown;
+        let ticks = draw.ticks();
+        // An emote's props: its time and weight while it plays.
+        let emote = emotes::pose_playing(draw.body_pose()).and_then(|p| {
+            let (t, w) = p.at(ticks)?;
+            (p.item.vertices > 0).then(|| (p.item.clone(), t, w))
+        });
+        let worn = match (&self.client, self.uuid_of(m)) {
+            (Some(client), Some(uuid)) if shown && bodies => client.frame().worn(uuid),
+            _ => None,
+        };
+        // Items on one bone (a back item, a shoulder pet and a shirt ride the body) share its
+        // matrix: the head, the body and the two arms at most.
+        let mut bones: [Option<(Bone, [[f32; 4]; 4])>; 4] = [None; 4];
+        let worn_items = worn.iter().flat_map(|w| w.iter()).map(|i| (i, None));
+        let emote_items = emote.iter().map(|(i, t, w)| (i, Some((*t, *w))));
+        for (item, emoting) in worn_items.chain(emote_items) {
+            // Covered by gear, or drawn by no bone (a name tag style, companions, trails, auras).
+            if emoting.is_none() && covered(m.gear, item.slot) {
+                continue;
+            }
+            let Some(uv) = self.uv(item, |id| draw.sprite(id)) else {
+                continue;
+            };
+            for i in 0..self.kept(item).meshes.len() {
+                let (bone_of, mesh) = self.kept(item).meshes[i].clone();
+                let known = bones.iter().flatten().find(|(b, _)| *b == bone_of);
+                let matrix = match known {
+                    Some(&(_, matrix)) => matrix,
+                    None => {
+                        let Some(matrix) = draw.bone(bone_of) else {
+                            continue;
+                        };
+                        if let Some(free) = bones.iter_mut().find(|b| b.is_none()) {
+                            *free = Some((bone_of, matrix));
+                        }
+                        matrix
+                    }
+                };
+                draw.draw(&mesh, matrix, Look::new(uv), &mut |p| {
+                    item.animate(ticks, |name, pose| *p.pose(name) = pose);
+                    if let (Some((t, w)), Some(e)) = (emoting, &item.emote) {
+                        e.pose_props(t, |n| item.rest(n), |n, pose| *p.pose(n) = pose);
+                        // Props grow in and shrink out with the emote's blend.
+                        let root = p.pose(&mesh.name);
+                        for s in &mut root[6..9] {
+                            *s *= w;
+                        }
+                    }
+                });
             }
         }
-        self.sprites
-            .retain(|_, (_, item)| Arc::strong_count(item) > 1);
     }
 
     /// Once a tick: names the Horizon players in view to the emote feed and plays what it says
@@ -922,104 +1043,47 @@ impl Game<'_> {
         }
     }
 
-    /// The cosmetics `m` wears, on its bones. `gpu`: posed on the GPU (the mob pass's skin
-    /// frame, begun); the bounds of what went there come back, for culling. Else the vertices
-    /// go to `out`. `camera`: where the world view's camera is; None in a picture of the player
-    /// (the inventory), which shows no companion, trail or aura.
+    /// The companion, trail and aura `m` wears, in the world (`camera`: where the view's camera
+    /// is); the items on its bones are the hook's (`Seat::player_layers`). `gpu`: a companion
+    /// goes on the GPU's skin path (the mob pass's skin frame, begun) and the bounds of what went
+    /// there come back, for culling; else its vertices go to `out`.
     #[allow(clippy::too_many_arguments)]
-    pub(super) fn cosmetics_geometry(
+    pub(super) fn cosmetics_fx_of(
         &self,
         m: &Mob,
         own: bool,
         base: glam::Mat4,
-        camera: Option<glam::DVec3>,
+        camera: glam::DVec3,
         alpha: f32,
         light: u32,
         gpu: bool,
         out: &mut Vec<horizon_client::mesher::Vertex>,
     ) -> Option<(glam::Vec3, glam::Vec3)> {
-        use horizon_client::mobs::{anim, render};
-        let worn = self.worn(m, own);
-        // An emote's props: its time and weight while it plays.
-        let ticks = m.age as f32 + alpha;
-        let emote = emotes::playing(m).and_then(|p| {
-            let (t, w) = p.at(ticks)?;
-            (p.item.vertices > 0).then_some((&p.item, t, w))
-        });
-        if worn.is_none() && emote.is_none() || horizon_client::mobs::trader::is_invisible(m) {
+        // "Name tags only": other players' styles beside their names, nothing around them.
+        let bodies = own || self.settings.extras.effective_others() == Others::Shown;
+        // The player's own in first person: only its companion, drawn after the drain of the
+        // first-person model (`cosmetics_fx_geometry`).
+        if !bodies || own && !self.own_body_in_view() {
             return None;
         }
-        // The avatar's body, posed as it is drawn.
-        let (key, _) = render::body(m);
-        let body = m.kind.layer(&key).unwrap_or(&m.kind.model);
-        let mut scratch = self.cosmetics.poses.borrow_mut();
-        let (body_poses, poses) = &mut *scratch;
-        body_poses.reset(body);
-        let data = self.res.mob_data();
-        anim::setup(m, &anim::state(m, alpha), body_poses, &data.animations);
+        let worn = self.worn(m, own)?;
+        if horizon_client::mobs::trader::is_invisible(m) {
+            return None;
+        }
+        let mut poses = self.cosmetics.poses.borrow_mut();
         let mut bounds = None;
-        // Items on one bone (a back item, a shoulder pet and a shirt ride the body) share its
-        // matrix: the head, the body and the two arms at most.
-        let mut bones: [Option<(horizon_cosmetics::Bone, glam::Mat4)>; 4] = [None; 4];
-        // "Name tags only": other players' styles beside their names, nothing on their bodies.
-        let bodies = own || self.settings.extras.effective_others() == Others::Shown;
-        let worn_items = worn.iter().flat_map(|w| w.iter()).map(|i| (i, None));
-        let emote_items = emote.map(|(i, t, w)| (i, Some((t, w))));
-        for (item, emoting) in worn_items.chain(emote_items) {
-            if emoting.is_none() && !bodies {
-                continue;
-            }
-            if let (Some(camera), Slot::Companion | Slot::Trail | Slot::Aura) = (camera, item.slot)
-            {
-                // The player's own in first person: only its companion, drawn after the drain
-                // of the first-person model (`cosmetics_fx_geometry`).
-                if !(own && !self.own_body_in_view()) {
-                    let at = fx::Wearer {
-                        m,
-                        own,
-                        key: if own { OWN } else { m.id },
-                        base,
-                        camera,
-                        alpha,
-                        light,
-                    };
-                    bounds = self.cosmetics_fx(&at, item, gpu, bounds, poses, out);
-                }
-                continue;
-            }
-            if emoting.is_none() && covered(super::player_hooks::gear(m), item.slot) {
-                continue;
-            }
-            let Some((models, uv)) = self.cosmetics_baked(item) else {
-                continue;
-            };
-            for (bone_of, model) in &models {
-                let known = bones.iter().flatten().find(|(b, _)| b == bone_of);
-                let bone = match known {
-                    Some(&(_, matrix)) => matrix,
-                    None => {
-                        let Some(matrix) =
-                            render::part_matrix(body, base, body_poses, bone_of.part(), 0.0)
-                        else {
-                            continue;
-                        };
-                        if let Some(free) = bones.iter_mut().find(|b| b.is_none()) {
-                            *free = Some((*bone_of, matrix));
-                        }
-                        matrix
-                    }
+        for item in worn.iter() {
+            if let Slot::Companion | Slot::Trail | Slot::Aura = item.slot {
+                let at = fx::Wearer {
+                    m,
+                    own,
+                    key: if own { OWN } else { m.id },
+                    base,
+                    camera,
+                    alpha,
+                    light,
                 };
-                poses.reset(model);
-                item.animate(ticks, |name, pose| *poses.get(name) = pose);
-                if let (Some((t, w)), Some(e)) = (emoting, &item.emote) {
-                    e.pose_props(t, |n| item.rest(n), |n, pose| *poses.get(n) = pose);
-                    // Props grow in and shrink out with the emote's blend.
-                    let root = poses.get(&model.name);
-                    for s in &mut root[6..9] {
-                        *s *= w;
-                    }
-                }
-                bounds = self.cosmetics_model(model, bone, poses, uv, light, gpu, bounds, out);
+                bounds = self.cosmetics_fx(&at, item, gpu, bounds, &mut poses, out);
             }
         }
         bounds
@@ -1398,4 +1462,124 @@ mod tests {
         service.tick(&mut view);
         assert!(view.0[3].1.is_none());
     }
+
+    /// A player model as `player_layers` draws on it: one bone, the sprites it is given; logs
+    /// each draw (mesh, matrix, uv, its root's scale once posed).
+    struct Canvas {
+        pose: Option<Arc<dyn BodyPose>>,
+        sprite: Option<[f32; 4]>,
+        drawn: Vec<(String, [[f32; 4]; 4], [f32; 4], [f32; 3])>,
+    }
+
+    const LEFT_ARM: [[f32; 4]; 4] = [[2.0, 0.0, 0.0, 0.0]; 4];
+
+    impl PlayerDraw for Canvas {
+        fn pass(&self) -> horizon_hooks::players::Pass {
+            horizon_hooks::players::Pass::World
+        }
+        fn ticks(&self) -> f32 {
+            102.0
+        }
+        fn base(&self) -> [[f32; 4]; 4] {
+            LEFT_ARM
+        }
+        fn motion(&self) -> horizon_hooks::players::Motion {
+            Default::default()
+        }
+        fn view(&self) -> horizon_hooks::players::View {
+            Default::default()
+        }
+        fn particles(
+            &mut self,
+            _: [f32; 4],
+            _: &[horizon_hooks::players::Particle],
+            _: horizon_hooks::players::Light,
+        ) {
+        }
+        fn bone(&mut self, bone: Bone) -> Option<[[f32; 4]; 4]> {
+            (bone == Bone::LeftArm).then_some(LEFT_ARM)
+        }
+        fn body_pose(&self) -> Option<&Arc<dyn BodyPose>> {
+            self.pose.as_ref()
+        }
+        fn sprite(&self, _: u64) -> Option<[f32; 4]> {
+            self.sprite
+        }
+        fn draw(
+            &mut self,
+            mesh: &Arc<Mesh>,
+            matrix: [[f32; 4]; 4],
+            look: Look,
+            pose: &mut dyn FnMut(&mut dyn horizon_hooks::players::PartPoses),
+        ) {
+            struct Rest(std::collections::HashMap<String, [f32; 9]>);
+            impl horizon_hooks::players::PartPoses for Rest {
+                fn pose(&mut self, name: &str) -> &mut [f32; 9] {
+                    self.0.entry(name.to_owned()).or_insert([0.0; 9])
+                }
+            }
+            let mut rest = Rest([(mesh.name.clone(), mesh.pose)].into());
+            pose(&mut rest);
+            let root = rest.0[&mesh.name];
+            self.drawn.push((
+                mesh.name.clone(),
+                matrix,
+                look.uv,
+                [root[6], root[7], root[8]],
+            ));
+        }
+    }
+
+    #[test]
+    fn an_emotes_prop_goes_on_its_bone_once_its_texture_is_in_scaled_by_the_blend() {
+        let pop = CROWN
+            .replace(
+                r#""slot": "head", "bone": "head""#,
+                r#""slot": "emote", "bone": "left_arm""#,
+            )
+            .replace(
+                r#""uv": [0, 0]}]}]}"#,
+                r#""uv": [0, 0]}]}],
+                "emote": {"length": 40, "blend": 4, "tracks": [
+                  {"part": "right_arm", "keys": [{"t": 0}, {"t": 40}]}]}}"#,
+            );
+        let item = Arc::new(Item::parse(pop.as_bytes()).unwrap());
+        let playing = horizon_cosmetics::Playing {
+            item: item.clone(),
+            start: 100.0,
+            stop: None,
+        };
+        let (_, weight) = playing.at(102.0).unwrap();
+        assert!(weight > 0.0 && weight < 1.0, "{weight}");
+        let player = PlayerModel::new(9, Kind::Player, Some(5), 102, false);
+        let mut view = View(vec![(player, None)]);
+        emotes::set_model_playing(&mut view, 9, Some(playing));
+        let mut canvas = Canvas {
+            pose: view.0[0].1.clone(),
+            sprite: None,
+            drawn: Vec::new(),
+        };
+        // Others' cosmetics hidden, no service: the player's own emote still shows.
+        let mut seat = Seat {
+            said: Said {
+                others_hidden: true,
+                ..Said::default()
+            },
+            ..Seat::default()
+        };
+        // Its texture not in the atlas yet: nothing drawn, the sprite asked for.
+        seat.player_layers(&player, &mut canvas);
+        assert!(canvas.drawn.is_empty());
+        assert_eq!(seat.wanted.len(), 1);
+        canvas.sprite = Some([0.0, 0.0, 0.5, 0.5]);
+        seat.player_layers(&player, &mut canvas);
+        // A 16×16 texture: the slot's top left quarter of it.
+        let quarter = 0.5 * 16.0 / 64.0;
+        assert_eq!(canvas.drawn.len(), 1);
+        let (_, matrix, uv, scale) = &canvas.drawn[0];
+        assert_eq!((matrix, uv), (&LEFT_ARM, &[0.0, 0.0, quarter, quarter]));
+        for s in scale {
+            assert!((s - weight).abs() < 1e-6, "{scale:?} by {weight}");
+        }
+    }
 }

crates/horizon-client/src/game/cosmetics/emotes.rs

@@ -71,11 +71,6 @@ pub(in crate::game) fn pose_playing(pose: Option<&Arc<dyn BodyPose>>) -> Option<
     any.downcast_ref::<EmotePose>().map(|e| &e.0)
 }
 
-/// The emote `m` plays, if any.
-pub(in crate::game) fn playing(m: &Mob) -> Option<&Playing> {
-    pose_playing(m.emote.as_ref())
-}
-
 /// The pose that plays `next` where `now` is laid, unless it plays that already (None: keep
 /// it; a new one allocates).
 fn replaced(

crates/horizon-client/src/game/cosmetics/fx.rs

@@ -314,8 +314,7 @@ impl Game<'_> {
             light = FULL_LIGHT;
         }
         let mut poses = self.cosmetics.poses.borrow_mut();
-        let poses = &mut poses.1;
-        self.pose_companion(item, m, alpha, poses, &model);
-        self.cosmetics_model(&model, matrix, poses, uv, light, false, None, out);
+        self.pose_companion(item, m, alpha, &mut poses, &model);
+        self.cosmetics_model(&model, matrix, &poses, uv, light, false, None, out);
     }
 }

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

@@ -1,49 +0,0 @@
-//! What the player is doing, for Discord Rich Presence (`horizon_client::discord_presence`).
-use super::*;
-use horizon_client::discord_presence::{self as presence, Dimension, Play, Status};
-
-impl Game<'_> {
-    /// Each frame: only a change reaches the presence thread.
-    pub(super) fn update_discord_presence(&self) {
-        // One Discord status per computer: P1's, not a splitscreen player's.
-        if self.options.split_guest {
-            return;
-        }
-        presence::set(self.discord_status());
-    }
-    fn discord_status(&self) -> Status {
-        if !self.settings.extras.discord_presence {
-            return Status::Off;
-        }
-        if self.title.is_some() {
-            return Status::Menus;
-        }
-        let play = if let Some(host) = &self.lan {
-            Play::Hosting {
-                players: 1 + host.hub.guests.len(),
-                max: horizon_client::lan::MAX_PLAYERS,
-            }
-        } else if let Some(server) = &self.integrated {
-            match (server.published(), &self.remote) {
-                (Some(_), Some(remote)) => Play::Hosting {
-                    players: remote.player_count(),
-                    max: horizon_client::lan::MAX_PLAYERS,
-                },
-                _ => Play::Singleplayer,
-            }
-        } else if self.remote.is_some() {
-            Play::Multiplayer
-        } else {
-            Play::Singleplayer
-        };
-        Status::World {
-            play,
-            dimension: match self.dim {
-                Dim::Overworld => Dimension::Overworld,
-                Dim::Nether => Dimension::Nether,
-                Dim::End => Dimension::End,
-            },
-            mode: self.mode,
-        }
-    }
-}

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

@@ -367,10 +367,7 @@ impl Game<'_> {
             // only in the GUI, where their own layers draw: held, dropped and framed items keep
             // vanilla's until theirs do. The pack's `useGlint=false` removes it everywhere.
             let gui = display == DisplayContext::Gui;
-            let pack_keeps = renderer
-                .cit
-                .as_ref()
-                .is_none_or(|c| c.rules.global.use_glint);
+            let pack_keeps = renderer.cit.as_ref().is_none_or(|c| c.rules.use_glint);
             if !glint.vanilla && (gui || !pack_keeps) {
                 for layer in &mut state.layers {
                     layer.foil = horizon_assets::item_model::FoilType::None;

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

@@ -34,8 +34,6 @@ pub(super) fn run_event_loop(mut game: Game<'_>) -> Result<()> {
     narrator::stop();
     leave_fullscreen_after(&result, &mut game.settings);
     result?;
-    #[cfg(feature = "discord")]
-    horizon_client::discord_presence::stop();
     write_report(&game)?;
     if let Some(e) = game.error.take() {
         return Err(e);
@@ -98,9 +96,8 @@ impl Loading {
             .map_or([1280, 720], |o| o.window_size)
             .map(f64::from);
         self.fullscreen = horizon_client::window::FullscreenState::new(fullscreen);
-        let attributes = horizon_client::window::with_horizon_icon(
-            Window::default_attributes().with_title("Horizon"),
-        );
+        let attributes =
+            horizon_client::window::with_icon(Window::default_attributes().with_title("Horizon"));
         // Wayland names the window by its app id, which the horizon.desktop entry matches.
         #[cfg(target_os = "linux")]
         let attributes = winit::platform::wayland::WindowAttributesExtWayland::with_name(
@@ -130,22 +127,25 @@ impl Loading {
         // redraw the same design when they start. GDI is unsafe:
         // horizon-threads holds it (this crate forbids unsafe code).
         #[cfg(target_os = "windows")]
-        let boot_paint_stop = hwnd(&window).map(|hwnd| {
-            let stop = std::sync::Arc::new(std::sync::atomic::AtomicBool::new(false));
-            let repaint_stop = stop.clone();
-            std::thread::spawn(move || {
-                while !repaint_stop.load(std::sync::atomic::Ordering::Relaxed) {
-                    horizon_threads::boot_paint::paint(
-                        hwnd,
-                        horizon_theme::fonts::GEIST_SEMIBOLD,
-                        horizon_theme::fonts::GEIST_MONO,
-                        &horizon_client::logging::recent_lines(),
-                    );
-                    std::thread::sleep(std::time::Duration::from_millis(300));
-                }
+        // In the fonts given to `menu_style`; with none, the window stays as it is.
+        let boot_paint_stop = hwnd(&window)
+            .zip(horizon_client::menu_style::get().fonts)
+            .map(|(hwnd, fonts)| {
+                let stop = std::sync::Arc::new(std::sync::atomic::AtomicBool::new(false));
+                let repaint_stop = stop.clone();
+                std::thread::spawn(move || {
+                    while !repaint_stop.load(std::sync::atomic::Ordering::Relaxed) {
+                        horizon_threads::boot_paint::paint(
+                            hwnd,
+                            fonts.semibold,
+                            fonts.mono,
+                            &horizon_client::logging::recent_lines(),
+                        );
+                        std::thread::sleep(std::time::Duration::from_millis(300));
+                    }
+                });
+                stop
             });
-            stop
-        });
         let offscreen = self.options.as_ref().is_some_and(|o| o.offscreen);
         let boot_step = startup::step("renderer.boot");
         match loading_renderer(

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

@@ -93,10 +93,9 @@ impl ApplicationHandler for Missing {
         if self.window.is_some() {
             return;
         }
-        let attributes = horizon_client::window::with_horizon_icon(
-            Window::default_attributes().with_title("Horizon"),
-        )
-        .with_inner_size(winit::dpi::LogicalSize::new(1040.0, 700.0));
+        let attributes =
+            horizon_client::window::with_icon(Window::default_attributes().with_title("Horizon"))
+                .with_inner_size(winit::dpi::LogicalSize::new(1040.0, 700.0));
         let made = event_loop
             .create_window(attributes)
             .map_err(Into::into)

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

@@ -801,19 +801,8 @@ impl Game<'_> {
                 packed,
                 out,
             );
-            if super::cosmetics::enabled() {
-                let base = horizon_client::mobs::render::base_transform(m, alpha as f32, camera);
-                self.cosmetics_geometry(
-                    m,
-                    true,
-                    base,
-                    Some(camera),
-                    alpha as f32,
-                    packed,
-                    false,
-                    out,
-                );
-            }
+            let world = horizon_hooks::players::Pass::World;
+            self.own_layers_geometry(m, world, camera, alpha as f32, packed, out);
             self.player_elytra_geometry(m, chest, camera, alpha as f32, packed, out);
             self.spin_attack_geometry(m, camera, alpha as f32, packed, out);
             self.shoulder_parrots_geometry(m, camera, alpha as f32, packed, out);
@@ -927,10 +916,8 @@ impl Game<'_> {
             240 | 240 << 8,
             &mut verts,
         );
-        if super::cosmetics::enabled() {
-            let base = horizon_client::mobs::render::base_transform(&m, 1.0, camera);
-            self.cosmetics_geometry(&m, true, base, None, 1.0, 240 | 240 << 8, false, &mut verts);
-        }
+        let picture = horizon_hooks::players::Pass::Picture;
+        self.own_layers_geometry(&m, picture, camera, 1.0, 240 | 240 << 8, &mut verts);
         // `WingsLayer` draws through `RenderTypes.armorCutoutNoCull`: the
         // wings' faces show from both sides (the elytra texture is empty on
         // the face that looks at the body).

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

@@ -738,14 +738,11 @@ impl Game<'_> {
         });
         self.set_pushed_on_ground(target, limited, resolved);
 
-        // Entity.move updates ground before its tiny-collision return. This
-        // native slice covers only unoccupied server NoAI horizontal moves.
-        if let Target::Entity(EntityHandle::Mob(i)) = target {
+        // shortcut: unoccupied server mobs only, expand when controller/passenger authority is bound.
+        let mob = if let Target::Entity(EntityHandle::Mob(i)) = target {
             let m = &self.mobs[i];
-            let eligible = !self.options.execution_role.is_client()
+            (!self.options.execution_role.is_client()
                 && self.remote.is_none()
-                && limited.y == 0.0
-                && m.no_ai
                 && !m.extra.passenger
                 && m.extra.mount.is_none()
                 && m.rider.is_none()
@@ -757,16 +754,22 @@ impl Game<'_> {
                         .guests
                         .iter()
                         .any(|g| host.hub.here(g) && g.vehicle == Some(m.id))
-                });
-            if eligible {
-                self.mobs[i].on_ground = limited.y < 0.0 && limited.y != resolved.y;
-            }
+                }))
+            .then_some(i)
+        } else {
+            None
+        };
+        // Entity.move updates ground before its tiny-collision return.
+        if let Some(i) = mob
+            && self.mobs[i].no_ai
+        {
+            self.mobs[i].on_ground = limited.y < 0.0 && limited.y != resolved.y;
+        }
+        let tnt_after_move =
+            tnt.is_some() && !self.options.execution_role.is_client() && self.remote.is_none();
+        if mob.is_none() && !tnt_after_move {
+            self.restitute_piston(target, limited, resolved);
         }
-        // `Entity.move(MoverType.PISTON, …)` restitution, which runs whether or
-        // not the step is applied: so a primed TNT in a chunk that does not tick
-        // entities still loses its velocity into walls and ceilings and
-        // bounces on slime (#12022).
-        self.restitute_piston(target, limited, resolved);
         let moved = resolved.length_squared() > 1.0e-7
             || limited.length_squared() - resolved.length_squared() < 1.0e-7;
         if moved {
@@ -775,6 +778,12 @@ impl Game<'_> {
             // A move the collisions cut to nothing still ends in the check.
             self.release_after_block_move(target);
         }
+        // Restitution reads the new landing block even when the push was blocked.
+        if let Some(i) = mob {
+            self.mobs[i].restitute_movement(&self.world, &self.motion.blocks, limited, resolved);
+        } else if tnt_after_move {
+            self.restitute_piston(target, limited, resolved);
+        }
         if let Some((i, from, ..)) = tnt {
             self.finish_tnt_piston_move(i, from, resolved);
         }
@@ -1053,6 +1062,7 @@ mod tests {
 mod order_tests {
     use crate::game::{Audio, Game, Options, Progress, Settings, load_resources};
     use horizon_client::chunk::Chunk;
+    use horizon_core::geometry::Vec3;
     use horizon_core::{geometry::Direction, position::BlockPos};
     use horizon_world::level::pistons::MovingPiston;
     use std::sync::Arc;
@@ -1151,8 +1161,9 @@ mod order_tests {
         }
         // The near stone's box reaches x 5.5 into a TNT from x 5.01: 0.49 plus
         // PUSH_OFFSET; the far stone's old box stops it at x 6.
+        // Vanilla's TNT width is 0.98F, not the exact decimal 0.98.
         assert!(
-            (moved[0] - 0.5).abs() < 1e-9,
+            (moved[0] - 0.500000009536743).abs() < 1e-9,
             "far stone gone first: {}",
             moved[0]
         );
@@ -1251,7 +1262,7 @@ mod order_tests {
     }
 
     /// A primed TNT pushed down by a piston onto a slime block bounces up,
-    /// matching vanilla's slime restitution (~+0.64) even in a lazy chunk (#12022).
+    /// matching vanilla's restitution even in a lazy chunk (#12022).
     #[test]
     #[ignore = "needs prepared resources in HORIZON_TEST_RESOURCES"]
     fn a_pushed_tnt_bounces_on_slime() {
@@ -1312,32 +1323,36 @@ mod order_tests {
             death_ticks: 0,
             id: 1,
         };
-        game.block_ticks.moving_pistons = vec![(BlockPos::new(5, 200, 5), piston)];
-        game.sync_moving_pistons();
-        game.tnts.clear();
-        assert!(game.run_command("summon tnt 5.5 200.5 5.5 {fuse:80,Motion:[0.0d,-0.4d,0.0d]}"));
-        assert!(
-            (game.tnts[0].velocity.y - (-0.4)).abs() < 1.0e-9,
-            "TNT starts with vy -0.4, got {:?}",
-            game.tnts[0].velocity
-        );
-        // Piston advances from progress 0 to 0.5 and pushes the TNT down.
-        let pushes: Vec<_> = game
-            .block_ticks
-            .moving_pistons
-            .iter()
-            .map(|&(pos, old)| (pos, old, old.progress + 0.5))
-            .collect();
-        for (_, piston) in &mut game.block_ticks.moving_pistons {
-            piston.progress += 0.5;
+        // Pinned 26.3 PistonMovingBlockEntity.moveCollidedEntities, without entity ticks.
+        for (floor, y, vy, final_y, final_vy) in [
+            (slime, 200.5, -0.4, 200.0, 0.3510000138133766_f64),
+            (stone, 200.5, -0.4, 200.0, 0.0),
+            (slime, 200.0, -0.4, 200.0, 0.3200000047683716),
+            (slime, 200.00001, -0.4, 200.00001, 0.32000064476813395),
+            (slime, 200.5, 0.3, 200.0, 0.0),
+        ] {
+            game.world.set(5, 199, 5, floor).unwrap();
+            game.block_ticks.moving_pistons = vec![(BlockPos::new(5, 200, 5), piston)];
+            game.sync_moving_pistons();
+            game.tnts.clear();
+            assert!(game.run_command(&format!(
+                "summon tnt 5.5 {y} 5.5 {{fuse:80,Motion:[0.0d,{vy}d,0.0d]}}"
+            )));
+            assert_eq!(game.tnts[0].velocity.y, vy);
+            let pushes: Vec<_> = game
+                .block_ticks
+                .moving_pistons
+                .iter()
+                .map(|&(pos, old)| (pos, old, old.progress + 0.5))
+                .collect();
+            for (_, piston) in &mut game.block_ticks.moving_pistons {
+                piston.progress += 0.5;
+            }
+            game.push_piston_entities(pushes);
+            assert_eq!(game.tnts[0].position, Vec3::new(5.5, final_y, 5.5));
+            assert_eq!(game.tnts[0].velocity.y.to_bits(), final_vy.to_bits());
+            assert!(game.tnts[0].on_ground);
         }
-        game.push_piston_entities(pushes);
-        // The slime block at y=199 bounces the TNT up; vertical velocity must be positive.
-        assert!(
-            game.tnts[0].velocity.y > 0.0,
-            "TNT should bounce up on slime, got vy {:?}",
-            game.tnts[0].velocity
-        );
     }
 }
 
@@ -1602,6 +1617,54 @@ mod h255_mob_piston_ground_tests {
     }
     #[test]
     #[ignore = "needs prepared resources in HORIZON_TEST_RESOURCES"]
+    fn h255_added_tnt_authority_and_exhausted_budget() {
+        use crate::game::execution_role::ExecutionRole;
+        for role in [
+            ExecutionRole::Client,
+            ExecutionRole::IntegratedServer,
+            ExecutionRole::DedicatedServer,
+        ] {
+            with_role_game(role, |game| {
+                assert!(game.run_command("setblock 5 199 5 slime_block"));
+                assert!(
+                    game.run_command("summon tnt 5.5 200.5 5.5 {fuse:80,Motion:[0d,-0.4d,0d]}")
+                );
+                let mut budget = std::collections::HashMap::new();
+                let push = |game: &mut Game<'_>,
+                            budget: &mut std::collections::HashMap<_, _>,
+                            movement| {
+                    let tnt = &game.tnts[0];
+                    game.move_pushed(
+                        Target::Entity(EntityHandle::Tnt(0)),
+                        tnt.bounds(),
+                        [tnt.position.x, tnt.position.z],
+                        0.0,
+                        tnt.on_ground,
+                        movement,
+                        Direction::Down,
+                        budget,
+                    );
+                };
+                push(game, &mut budget, Vec3::ZERO);
+                assert_eq!(game.tnts[0].position.y, 200.5);
+                assert_eq!(game.tnts[0].velocity.y, -0.4);
+                push(game, &mut budget, Vec3::new(0.0, -0.51, 0.0));
+                let expected = if role.is_client() {
+                    0.0_f64
+                } else {
+                    0.3510000138133766
+                };
+                assert_eq!(game.tnts[0].velocity.y.to_bits(), expected.to_bits());
+                game.tnts[0].position.y = 200.5;
+                game.tnts[0].velocity.y = -0.4;
+                push(game, &mut budget, Vec3::new(0.0, -0.51, 0.0));
+                assert_eq!(game.tnts[0].position.y, 200.5);
+                assert_eq!(game.tnts[0].velocity.y, -0.4);
+            });
+        }
+    }
+    #[test]
+    #[ignore = "needs prepared resources in HORIZON_TEST_RESOURCES"]
     fn h255_added_no_request_and_exhausted_budget_keep_state() {
         with_game(|game| {
             let i = added_mob(game, 20, "horse", true, 8.5);
@@ -1613,6 +1676,16 @@ mod h255_mob_piston_ground_tests {
             added_push(game, i, Vec3::new(0.51, 0.0, 0.0));
             assert!(game.mobs[i].on_ground, "occupied path remains excluded");
             assert_eq!(game.mobs[i].position, Vec3::new(9.01, 202.0, 4.5));
+            assert!(game.run_command("setblock 9 201 4 slime_block"));
+            game.mobs[i].position.y = 202.25;
+            game.mobs[i].velocity = Vec3::new(0.0, -1.0, 0.0);
+            game.mobs[i].sync_position = false;
+            added_push(game, i, Vec3::new(0.0, -0.5, 0.0));
+            assert_eq!(
+                game.mobs[i].velocity.y, 0.0,
+                "occupied restitution stays outside this slice"
+            );
+            assert!(!game.mobs[i].sync_position);
             assert!(game.run_command("ride @s dismount"));
             assert!(game.riding.is_none());
             assert!(game.mobs[i].rider.is_none());
@@ -1655,23 +1728,46 @@ mod h255_mob_piston_ground_tests {
     }
     #[test]
     #[ignore = "needs prepared resources in HORIZON_TEST_RESOURCES"]
-    fn h255_added_client_role_ai_and_vertical_paths_keep_native_state() {
+    fn h255_added_client_role_ai_and_vertical_ground_state() {
         use crate::game::execution_role::ExecutionRole as Role;
-        for (role, no_ai, movement) in [
-            (Role::Client, true, Vec3::new(0.25, 0.0, 0.0)),
-            (Role::IntegratedServer, false, Vec3::new(0.25, 0.0, 0.0)),
-            (Role::IntegratedServer, true, Vec3::new(0.0, 0.25, 0.0)),
+        for (role, no_ai, movement, on_ground) in [
+            (Role::Client, true, Vec3::new(0.25, 0.0, 0.0), true),
+            (
+                Role::IntegratedServer,
+                false,
+                Vec3::new(0.25, 0.0, 0.0),
+                true,
+            ),
+            (
+                Role::IntegratedServer,
+                true,
+                Vec3::new(0.0, 0.25, 0.0),
+                false,
+            ),
         ] {
             with_role_game(role, |game| {
                 let i = added_mob(game, 22, "husk", no_ai, 8.5);
                 let before = game.mobs[i].position;
                 added_push(game, i, movement);
                 assert_eq!(game.mobs[i].position, before.add_vector(movement));
-                assert!(
-                    game.mobs[i].on_ground,
-                    "excluded native path remains unchanged; not Java parity"
-                );
+                assert_eq!(game.mobs[i].on_ground, on_ground);
             });
         }
     }
+
+    #[test]
+    #[ignore = "needs prepared resources in HORIZON_TEST_RESOURCES"]
+    fn h255_added_partial_push_reads_slime_after_the_position_changes() {
+        with_game(|game| {
+            assert!(game.run_command("setblock 8 201 4 slime_block"));
+            let i = added_mob(game, 23, "iron_golem", true, 8.5);
+            game.mobs[i].position.y = 202.25;
+            game.mobs[i].velocity = Vec3::new(0.0, -1.0, 0.0);
+            game.mobs[i].sync_position = false;
+            added_push(game, i, Vec3::new(0.0, -0.5, 0.0));
+            assert_eq!(game.mobs[i].position, Vec3::new(8.5, 202.0, 4.5));
+            assert!(game.mobs[i].velocity.y > 0.9);
+            assert!(game.mobs[i].sync_position);
+        });
+    }
 }

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

@@ -11,8 +11,8 @@ use horizon_client::mobs::anim::{self, BodyPose, PooledPoses, Poses};
 use horizon_client::mobs::{Mob, Part, Polygon, render};
 use horizon_hooks::engine;
 use horizon_hooks::players::{
-    Bone, CameraView, Frame, Gear, Kind, Mesh, PartPoses, Pass, PlayerDraw, PlayerModel,
-    PlayerModels, SpriteStore, Sprites,
+    Bone, CameraView, Frame, Gear, Kind, Light, Look, Mesh, Motion, PartPoses, Particle, Pass,
+    PlayerDraw, PlayerModel, PlayerModels, SpriteStore, Sprites, View,
 };
 use std::sync::Arc;
 
@@ -182,6 +182,14 @@ fn part_of(mesh: &Arc<Mesh>) -> Arc<Part> {
     })
 }
 
+/// Full light, packed as the vertices carry it.
+const FULL: u32 = 240 | 240 << 8;
+
+thread_local! {
+    /// What crates draw see-through this frame, added after every player.
+    static SEE_THROUGH: std::cell::RefCell<Vec<Vertex>> = const { std::cell::RefCell::new(Vec::new()) };
+}
+
 /// Forgets the meshes no crate holds any more (once a frame).
 fn forget_meshes() {
     let _ = MESHES.try_with(|m| {
@@ -199,7 +207,7 @@ impl PartPoses for PosesOf<'_> {
     }
 }
 
-/// A player model drawn in the world pass, as a crate draws on it: posed on the GPU's skin path
+/// A player model drawn, as a crate draws on it: posed on the GPU's skin path
 /// when `gpu` (the mob pass's skin frame, begun; the bounds of what went there grow, for
 /// culling), else its vertices go to `out`.
 struct DrawPlayer<'a, 'g> {
@@ -208,6 +216,7 @@ struct DrawPlayer<'a, 'g> {
     pass: Pass,
     /// The model's matrix (`render::base_transform`).
     base: glam::Mat4,
+    camera: glam::DVec3,
     alpha: f32,
     light: u32,
     gpu: bool,
@@ -223,6 +232,19 @@ impl DrawPlayer<'_, '_> {
         let (key, _) = render::body(self.m);
         self.m.kind.layer(&key).unwrap_or(&self.m.kind.model)
     }
+
+    /// `light` packed; `at`: the place `Light::AtPlace` reads, relative to the camera.
+    fn packed(&self, light: Light, at: glam::Vec3) -> u32 {
+        match light {
+            Light::Full => FULL,
+            Light::AtPlace => {
+                let p = (self.camera + at.as_dvec3()).floor();
+                let l = self.game.world.light(p.x as i32, p.y as i32, p.z as i32);
+                (u32::from(l >> 4) * 16) | ((u32::from(l & 15) * 16) << 8)
+            }
+            _ => self.light,
+        }
+    }
 }
 
 impl PlayerDraw for DrawPlayer<'_, '_> {
@@ -234,7 +256,52 @@ impl PlayerDraw for DrawPlayer<'_, '_> {
         self.m.age as f32 + self.alpha
     }
 
+    fn base(&self) -> [[f32; 4]; 4] {
+        self.base.to_cols_array_2d()
+    }
+
+    fn motion(&self) -> Motion {
+        let (m, a) = (self.m, self.alpha);
+        let t = f64::from(a);
+        let (p, n) = (m.previous, m.position);
+        let feet = [
+            p.x + (n.x - p.x) * t,
+            p.y + (n.y - p.y) * t,
+            p.z + (n.z - p.z) * t,
+        ];
+        let turn = horizon_client::mobs::living::wrap(m.head_yaw - m.previous_head_yaw);
+        let yaw = m.previous_head_yaw + turn * a;
+        let pitch = m.previous_head_pitch + (m.head_pitch - m.previous_head_pitch) * a;
+        let asleep = m.extra.avatar_pose == horizon_client::pose::Pose::Sleeping;
+        let swimming = m.extra.swim.amount(a) > 0.0;
+        Motion::new(feet, yaw, pitch).poses(
+            m.extra.crouching,
+            asleep,
+            m.extra.fall_flying,
+            swimming,
+        )
+    }
+
+    fn view(&self) -> View {
+        let q = self.game.camera_orientation();
+        let (right, up) = (
+            (q * glam::Vec3::X).to_array(),
+            (q * glam::Vec3::Y).to_array(),
+        );
+        let (yaw, pitch) = (self.game.yaw.to_radians(), self.game.pitch.to_radians());
+        let forward = [
+            -yaw.sin() * pitch.cos(),
+            -pitch.sin(),
+            yaw.cos() * pitch.cos(),
+        ];
+        let left = [yaw.cos(), 0.0, yaw.sin()];
+        View::new(self.camera.to_array(), right, up).looking(forward, left)
+    }
+
     fn bone(&mut self, bone: Bone) -> Option<[[f32; 4]; 4]> {
+        if self.pass == Pass::FirstPerson {
+            return None;
+        }
         if self.body.is_none() {
             let mut poses = Poses::pooled();
             poses.reset(self.body());
@@ -260,13 +327,30 @@ impl PlayerDraw for DrawPlayer<'_, '_> {
         &mut self,
         mesh: &Arc<Mesh>,
         matrix: [[f32; 4]; 4],
-        uv: [f32; 4],
+        look: Look,
         pose: &mut dyn FnMut(&mut dyn PartPoses),
     ) {
         let model = part_of(mesh);
         let matrix = glam::Mat4::from_cols_array_2d(&matrix);
+        let (uv, light) = (look.uv, self.packed(look.light, matrix.w_axis.truncate()));
         self.poses.reset(&model);
         pose(&mut PosesOf(&mut self.poses));
+        let poses = &self.poses;
+        if let Some(alpha) = look.see_through {
+            let color = ((alpha.clamp(0.0, 1.0) * 255.0) as u32) << 24 | 0x00FF_FFFF;
+            let pose_of = |p: &Part| poses.pose(p);
+            SEE_THROUGH.with_borrow_mut(|out| {
+                let start = out.len();
+                horizon_client::mobs::render_model(&model, matrix, &pose_of, uv, light, 0, out);
+                for v in &mut out[start..] {
+                    v.color = color;
+                    // Seen through, a face turned away would add to the near one: `entity.wgsl`
+                    // drops back faces, so it is `alpha` at most.
+                    v.normal[3] = horizon_client::mesher::SHADED_CULL_W;
+                }
+            });
+            return;
+        }
         if self.gpu {
             let mut models = self.game.skin_models.borrow_mut();
             let mut frame = self.game.skin_frame.borrow_mut();
@@ -276,24 +360,37 @@ impl PlayerDraw for DrawPlayer<'_, '_> {
                 uv,
                 scroll: 0.0,
                 color: 0xFFFF_FFFF,
-                light: self.light,
+                light,
                 overlay: 0,
             };
-            if skin.draw(&model, matrix, &self.poses, paint) {
+            if skin.draw(&model, matrix, poses, paint) {
                 self.bounds = skin.bounds;
                 return;
             }
         }
-        let poses = &self.poses;
-        horizon_client::mobs::render_model(
-            &model,
-            matrix,
-            &|p: &Part| poses.pose(p),
-            uv,
-            self.light,
-            0,
-            self.out,
-        );
+        let pose_of = |p: &Part| poses.pose(p);
+        horizon_client::mobs::render_model(&model, matrix, &pose_of, uv, light, 0, self.out);
+    }
+
+    fn particles(&mut self, uv: [f32; 4], particles: &[Particle], light: Light) {
+        let light = self.packed(light, glam::Vec3::ZERO);
+        SEE_THROUGH.with_borrow_mut(|out| {
+            for q in particles {
+                let color = ((q.alpha.clamp(0.0, 1.0) * 255.0) as u32) << 24 | 0x00FF_FFFF;
+                for (corner, [u, v]) in q.corners.iter().zip(q.uv) {
+                    out.push(Vertex {
+                        pos: *corner,
+                        uv: [uv[0] + (uv[2] - uv[0]) * u, uv[1] + (uv[3] - uv[1]) * v],
+                        layer: 0,
+                        color,
+                        light,
+                        // Unlit: a particle keeps its colour whichever way it faces.
+                        normal: [0, 0, 0, 0],
+                        glint_uv: [0.0, 0.0],
+                    });
+                }
+            }
+        });
     }
 }
 
@@ -324,6 +421,7 @@ impl Game<'_> {
                 m,
                 pass: Pass::World,
                 base,
+                camera,
                 alpha,
                 light,
                 gpu,
@@ -336,7 +434,7 @@ impl Game<'_> {
             bounds = draw.bounds;
         }
         let worn = super::cosmetics::enabled()
-            .then(|| self.cosmetics_geometry(m, false, base, Some(camera), alpha, light, gpu, out))
+            .then(|| self.cosmetics_fx_of(m, false, base, camera, alpha, light, gpu, out))
             .flatten();
         match (bounds, worn) {
             (Some((l, h)), Some((lo, hi))) => Some((l.min(lo), h.max(hi))),
@@ -344,6 +442,93 @@ impl Game<'_> {
         }
     }
 
+    /// What crates draw on the window's own model `m` (its vertices to `out`): in the world in
+    /// third person (`Pass::World`, then the cosmetics' companion, trail and aura still drawn
+    /// here), or in the inventory's picture of it (`Pass::Picture`). `camera`: the world view's
+    /// camera, or the picture's.
+    pub(super) fn own_layers_geometry(
+        &self,
+        m: &Mob,
+        pass: Pass,
+        camera: glam::DVec3,
+        alpha: f32,
+        light: u32,
+        out: &mut Vec<Vertex>,
+    ) {
+        debug_assert!(
+            self.serving.is_none(),
+            "a server thread calls no client hook"
+        );
+        let fx = pass == Pass::World && super::cosmetics::enabled();
+        if !engine::any() && !fx {
+            return;
+        }
+        let base = render::base_transform(m, alpha, camera);
+        if engine::any() {
+            let model = model(m, Kind::Own, self.remote.as_ref().map(|r| r.profile()));
+            let mut draw = DrawPlayer {
+                game: self,
+                m,
+                pass,
+                base,
+                camera,
+                alpha,
+                light,
+                gpu: false,
+                out: &mut *out,
+                bounds: None,
+                body: None,
+                poses: Poses::pooled(),
+            };
+            engine::player_layers(&model, &mut draw);
+        }
+        if fx {
+            self.cosmetics_fx_of(m, true, base, camera, alpha, light, false, out);
+        }
+    }
+
+    /// After every player (`game.rs`): what crates draw around the window's own model in first
+    /// person, the cosmetics' fx still drawn here, then what was drawn see-through, in one span.
+    pub(super) fn players_after_geometry(
+        &self,
+        camera: glam::DVec3,
+        alpha: f64,
+        out: &mut Vec<Vertex>,
+    ) {
+        if engine::any()
+            && !self.own_body_in_view()
+            && let Some(m) = self.player_model.as_ref()
+        {
+            let own = model(m, Kind::Own, self.remote.as_ref().map(|r| r.profile()));
+            let own = own.looks(own.gear, own.invisible || self.own_invisible());
+            self.mark_entity(out.len(), "minecraft:player");
+            let mut draw = DrawPlayer {
+                game: self,
+                m,
+                pass: Pass::FirstPerson,
+                base: render::base_transform(m, alpha as f32, camera),
+                camera,
+                alpha: alpha as f32,
+                light: FULL,
+                gpu: false,
+                out: &mut *out,
+                bounds: None,
+                body: None,
+                poses: Poses::pooled(),
+            };
+            engine::first_person(&own, &mut draw);
+        }
+        self.cosmetics_fx_geometry(camera, alpha, out);
+        let _ = SEE_THROUGH.try_with(|v| {
+            let mut v = v.borrow_mut();
+            if !v.is_empty() {
+                self.mark_translucent_entity(out.len(), "minecraft:player");
+                out.extend_from_slice(&v);
+                v.clear();
+            }
+        });
+    }
+
     /// Once a frame, before drawing.
     pub(super) fn client_hooks_frame(&mut self) {
         debug_assert!(
@@ -358,6 +543,7 @@ impl Game<'_> {
         let frame = Frame::new(connection, self.integrated.is_some());
         engine::frame(&frame, &mut HookStore(self));
         forget_meshes();
+        let _ = SEE_THROUGH.try_with(|v| v.borrow_mut().clear());
         self.cosmetics_frame();
     }
 

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

@@ -3,9 +3,9 @@
 //! checks (`horizon_client::mobs::random_textures`).
 
 use super::Game;
+use horizon_client::entity_textures::Weather;
 use horizon_client::mobs::random_textures::{Seen, choose, seed};
 use horizon_core::geometry::Vec3;
-use horizon_optifine::random::Weather;
 
 impl Game<'_> {
     pub(super) fn tick_random_textures(&mut self) {

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

@@ -11463,8 +11463,7 @@ impl Remote {
     pub(super) fn listed_player_count(&self) -> usize {
         self.listed.len()
     }
-    /// Players in the server's player list, this one included (for Discord).
-    #[cfg(feature = "discord")]
+    /// Players in the server's player list, this one included (for the activity hooks).
     pub(super) fn player_count(&self) -> usize {
         self.players.len()
     }

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

@@ -306,8 +306,6 @@ pub(super) fn run_loading(
         App::Loading(loading) => leave_fullscreen_after(&result, &mut loading.settings),
     }
     result?;
-    #[cfg(feature = "discord")]
-    horizon_client::discord_presence::stop();
     match app {
         App::Ready(mut split) => {
             write_report(&split.host)?;

crates/horizon-client/src/game/split/windows.rs

@@ -516,10 +516,9 @@ impl<'a> Split<'a> {
                 continue;
             }
             // Opened without the focus: whoever types in the game's window keeps the keyboard.
-            let attributes =
-                horizon_client::window::with_horizon_icon(Window::default_attributes())
-                    .with_active(false)
-                    .with_visible(window_shown(true, self.offscreen));
+            let attributes = horizon_client::window::with_icon(Window::default_attributes())
+                .with_active(false)
+                .with_visible(window_shown(true, self.offscreen));
             // A monitor's window covers it, borderless. On macOS not the system's fullscreen, a
             // Space of its own that hides the other windows as it slides in.
             let placement = self.placement(*key).cloned();

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

@@ -273,9 +273,8 @@ impl ApplicationHandler for Game<'_> {
         let fullscreen = self.settings.fullscreen || self.options.fullscreen;
         let size = self.options.window_size.map(f64::from);
         self.fullscreen = horizon_client::window::FullscreenState::new(fullscreen);
-        let attributes = horizon_client::window::with_horizon_icon(
-            Window::default_attributes().with_title("Horizon"),
-        );
+        let attributes =
+            horizon_client::window::with_icon(Window::default_attributes().with_title("Horizon"));
         // Wayland names the window by its app id, which the horizon.desktop entry matches.
         #[cfg(target_os = "linux")]
         let attributes = winit::platform::wayland::WindowAttributesExtWayland::with_name(

crates/horizon-client/src/horizon_look.rs

@@ -0,0 +1,56 @@
+//! Horizon's look, given to the engine's extension points at startup (docs/layers.md): the
+//! windows' icon and the colours, sizes and fonts of the menus vanilla doesn't have
+//! (`docs/design-system.md`).
+//! Its own module so it can leave the engine crate as a pure file move, for the official
+//! executable to call.
+use horizon_client::menu_style::{Fonts, MenuStyle, OverlayColours, SettingsColours, Sizes};
+use horizon_theme as theme;
+
+/// Give the engine Horizon's look; call it once, before the first window opens.
+pub(crate) fn give() {
+    horizon_client::window::set_icon_png(theme::ICON_PNG);
+    let (blocks, dark) = (theme::BLOCKS_DARK, theme::DARK);
+    horizon_client::menu_style::install(MenuStyle {
+        settings: SettingsColours {
+            page: blocks.page,
+            ink: blocks.ink,
+            ink_soft: blocks.ink_soft,
+            muted: blocks.muted,
+            outline: blocks.outline,
+            accent: blocks.accent,
+            face: blocks.face,
+            // The face's hover, lighter than `face`: the settings screen's own shade.
+            face_hover: 0x6a50e6,
+            success: blocks.success,
+            warn: blocks.warn,
+            danger: blocks.danger,
+        },
+        overlay: OverlayColours {
+            page: dark.page,
+            backdrop_muted: theme::BACKDROP_MUTED,
+            ink: dark.ink,
+            ink_soft: dark.ink_soft,
+            rule: dark.rule,
+            accent: dark.accent,
+            on_accent: dark.on_accent,
+        },
+        sizes: Sizes {
+            caption: theme::CAPTION.px,
+            label: theme::LABEL.px,
+            ui: theme::UI.px,
+            body: theme::BODY.px,
+            title: theme::TITLE.px,
+            display: theme::DISPLAY.px,
+            micro: theme::MICRO.px,
+            radius: theme::RADIUS,
+            radius_plate: theme::RADIUS_PLATE,
+            control_large: theme::CONTROL_LARGE,
+        },
+        fonts: Some(Fonts {
+            regular: theme::fonts::GEIST_REGULAR,
+            medium: theme::fonts::GEIST_MEDIUM,
+            semibold: theme::fonts::GEIST_SEMIBOLD,
+            mono: theme::fonts::GEIST_MONO,
+        }),
+    });
+}

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

@@ -1,4 +1,4 @@
-//! OptiFine Custom Item Textures on item models: the layer of a stack a `type=item` rule matches
+//! Custom item textures on item models: the layer of a stack an item rule (`Kind::Item`) matches
 //! draws the rule's model, or its own model with the rule's textures in some slots. The rules'
 //! JSON models join the model library, their textures the atlas (`cit_assets`).
 
@@ -105,7 +105,7 @@ pub(super) fn load(
 ) -> (Arc<ModelLibrary>, Option<CitModels>) {
     let rules = CitRules::load(root);
     // A `cit.properties` alone can still turn vanilla's glint off.
-    if rules.is_empty() && rules.global.use_glint {
+    if rules.is_empty() && rules.use_glint {
         return (library, None);
     }
     let extra = cit_assets::load_models(root, &rules.rules);
@@ -387,6 +387,7 @@ mod tests {
 
     /// A stick, a bow's frames and a potion; with `cit`, rules over them.
     fn root(name: &str, cit: bool) -> PathBuf {
+        crate::pack_formats::install();
         let root = std::env::temp_dir().join(format!("horizon-cit-{name}-{}", std::process::id()));
         let _ = fs::remove_dir_all(&root);
         let write = |rel: &str, text: &str| {
@@ -719,11 +720,8 @@ mod tests {
     }
 
     fn armor_rules(text: &str) -> CitRules {
-        let props = horizon_optifine::Properties::parse_equals_first(text);
         let path = "assets/minecraft/optifine/cit/worn.properties";
-        CitRules::new(vec![
-            crate::cit::Rule::parse(path, &props, |_| true).unwrap(),
-        ])
+        crate::pack_formats::cit::parse_rules(&[(path, text)], "")
     }
 
     #[test]

crates/horizon-client/src/item_render/gui.rs

@@ -692,23 +692,22 @@ mod tests {
 
     #[test]
     fn cit_layers_draw_once_over_the_whole_item() {
-        use crate::cit_glint::Global;
+        use crate::cit_glint::GlintLayer;
         use crate::hud::Blend;
         use crate::hud::cit_glint::Slot;
-        use horizon_optifine::Properties;
         let rule = |name: &str, text: &str| {
             let path = format!("assets/minecraft/optifine/cit/{name}.properties");
             let text = format!("type=enchantment\ntexture=glint\n{text}");
-            Rule::parse(&path, &Properties::parse_equals_first(&text), |_| true).unwrap()
+            crate::pack_formats::cit::parse_rule(&path, &text).unwrap()
         };
         let rules = [
             rule("shown", ""),
             rule("fire", "layer=1\nenchantments=fire_aspect"),
         ];
-        // Shared by level, and the stack has no Fire Aspect: that layer is at intensity 0.
-        let global = Global::parse(&Properties::parse_equals_first("method=average"));
-        let glint = StackGlint::new(&rules, &[0, 1], &[("minecraft:sharpness", 3)], &global);
-        assert_eq!(glint.layers.len(), 2);
+        // The second layer at intensity 0 (shared by level, and the stack has none of its
+        // enchantment).
+        let layers = vec![GlintLayer::new(0, 1.0, 1.0), GlintLayer::new(1, 0.0, 1.0)];
+        let glint = StackGlint::from_parts(layers, false, None);
         let slot = |blend| Slot {
             rgba: [1.0; 4],
             blur: false,

crates/horizon-client/src/lib.rs

@@ -6,6 +6,7 @@ extern crate self as horizon_client;
 pub use horizon_client_lib::*;
 pub mod entry;
 pub mod game;
+mod horizon_look;
 pub mod mod_api;
 
 #[cfg(test)]

crates/horizon-client/src/mob_formats/mod.rs

@@ -0,0 +1,31 @@
+//! The pack formats vanilla doesn't read that shape mobs (OptiFine's and Entity Model Features'
+//! custom entity models) on the engine's extension point ([`crate::mobs::cem::install`]). Platform
+//! code (docs/layers.md) kept in this crate until a platform crate installs it: it uses only the
+//! crate's public API, and nothing else in the crate names it.
+
+pub mod cem;
+mod cem_anim;
+
+use crate::mobs::MobType;
+use crate::mobs::cem::{CemModels, ModelFormats};
+use std::collections::HashMap;
+use std::path::Path;
+use std::sync::Arc;
+
+/// OptiFine's custom entity models.
+pub struct Formats;
+
+impl ModelFormats for Formats {
+    fn entity_models(
+        &self,
+        root: &Path,
+        types: &HashMap<String, Arc<MobType>>,
+    ) -> (CemModels, Vec<String>) {
+        cem::load(root, types)
+    }
+}
+
+/// Installs these formats ([`crate::mobs::cem::install`]); the game does at startup.
+pub fn install() {
+    crate::mobs::cem::install(&Formats);
+}

crates/horizon-client/src/mobs/data.rs

@@ -51,11 +51,11 @@ pub struct MobData {
     /// The packs' custom entity models (OptiFine CEM); replaced when the resource packs change.
     pub cem: std::sync::RwLock<std::sync::Arc<super::cem::CemModels>>,
     /// The packs' random entity textures, replaced with them too.
-    pub random_textures: std::sync::RwLock<horizon_optifine::random_textures::RandomTextures>,
+    pub random_textures: std::sync::RwLock<crate::entity_textures::RandomTextures>,
     /// The packs' emissive overlays of entity textures, replaced with them too.
-    pub emissive: std::sync::RwLock<std::sync::Arc<horizon_optifine::emissive::Emissive>>,
+    pub emissive: std::sync::RwLock<std::sync::Arc<crate::entity_textures::Emissive>>,
     /// ETF's blinking textures, replaced with the packs too.
-    pub blinks: std::sync::RwLock<horizon_optifine::blink::Blinks>,
+    pub blinks: std::sync::RwLock<crate::entity_textures::Blinks>,
     /// Biome tags (spawns_warm_variant_farm_animals, is_ocean...) by tag id.
     pub biome_tags: HashMap<String, std::collections::HashSet<String>>,
     /// Entity type tags (`data/*/tags/entity_type`).
@@ -92,10 +92,11 @@ impl MobData {
             crate::items::load_tags(root, "entity_type", &horizon_world::loot::PackOverlay::NONE)
                 .unwrap_or_default();
         data.villager_hats = std::sync::RwLock::new(super::villager_hats::VillagerHats::load(root));
-        let random = horizon_optifine::random_textures::RandomTextures::scan(root);
-        let blinks = horizon_optifine::blink::Blinks::scan(root, &random);
-        let mut emissive = horizon_optifine::emissive::Emissive::scan(root, &random);
-        emissive.pair_beside(root, blinks.files());
+        let crate::entity_textures::EntityTextures {
+            random,
+            blinks,
+            emissive,
+        } = crate::entity_textures::EntityTextures::load(root);
         data.emissive = std::sync::RwLock::new(std::sync::Arc::new(emissive));
         data.blinks = std::sync::RwLock::new(blinks);
         data.random_textures = std::sync::RwLock::new(random);

crates/horizon-client/src/mobs/living.rs

@@ -849,7 +849,6 @@ impl Mob {
         self.horizontal_collision = x_hit || z_hit;
         // A server's mobs are authoritative (`isLocalInstanceAuthoritative`):
         // the vertical flags update even without vertical movement.
-        let moved_vertically = wanted.y.abs() > 0.0;
         let vertical = wanted.y != moved.y;
         self.vertical_collision_below = vertical && wanted.y < 0.0;
         self.on_ground = self.vertical_collision_below;
@@ -857,42 +856,51 @@ impl Mob {
         // checkFallDamage reads the landing block (getOnPosLegacy).
         self.supporting = self.supporting_block(w, moved);
         self.species_check_fall_damage(w, moved, events);
-        // Entity.restituteMovementAfterCollisions: the colliding components
-        // bounce back by the entity's bounciness or the block's (a slime
-        // block, a bed), whichever is larger. A mob never sneaks, so nothing
-        // suppresses its bounce there.
-        if moved_vertically && vertical || self.horizontal_collision {
-            // Entity.getOnPos(0.2F): the block whose bounce this move sees.
+        self.restitute_movement(w.world, w.movement, wanted, moved);
+        self.movement_emission(w, moved, events);
+        // Entity.move's last step: soul sand, honey and the like slow the
+        // horizontal speed of whatever the mob stands in or on.
+        let factor = self.block_speed_factor(w);
+        self.velocity = horizon_world::entity_move::scale_by_block_speed(self.velocity, factor);
+    }
+    /// `Entity.restituteMovementAfterCollisions`, shared by travel and piston pushes.
+    pub fn restitute_movement(
+        &mut self,
+        world: &crate::world::World,
+        movement: &horizon_world::movement_properties::BoundMovementProperties,
+        wanted: Vec3,
+        moved: Vec3,
+    ) {
+        let differs = |a: f64, b: f64| (b - a).abs() >= f64::from(1.0e-5_f32);
+        let x_hit = differs(wanted.x, moved.x);
+        let z_hit = differs(wanted.z, moved.z);
+        let vertical = wanted.y != moved.y;
+        if wanted.y.abs() > 0.0 && vertical || x_hit || z_hit {
             let on = (
                 self.position.x.floor() as i32,
                 (self.position.y - f64::from(0.2_f32)).floor() as i32,
                 self.position.z.floor() as i32,
             );
             let input = RestitutionInput {
-                block: w.world.block(on.0, on.1, on.2),
+                block: world.block(on.0, on.1, on.2),
                 collided_x: x_hit,
                 collided_z: z_hit,
                 vertical_collision: vertical,
-                collision_below: self.vertical_collision_below,
+                collision_below: vertical && wanted.y < 0.0,
                 living: true,
                 resolved_movement: moved,
                 fall_distance: self.fall_distance,
             };
-            // The port's phases cannot fail for a mob: a block outside the
-            // registry reads as one with no bounce, never as an error.
+            // Unknown block states have no bounce; the provider cannot fail.
             let _ = restitute_movement(
                 &mut MobRestitution {
                     mob: self,
-                    world: w,
+                    world,
+                    movement,
                 },
                 input,
             );
         }
-        self.movement_emission(w, moved, events);
-        // Entity.move's last step: soul sand, honey and the like slow the
-        // horizontal speed of whatever the mob stands in or on.
-        let factor = self.block_speed_factor(w);
-        self.velocity = horizon_world::entity_move::scale_by_block_speed(self.velocity, factor);
     }
     /// `Entity.getBlockSpeedFactor` at the mob's feet.
     fn block_speed_factor(&self, w: &MobWorld) -> f32 {
@@ -2103,20 +2111,21 @@ pub fn client_water_splash(mob: &mut Mob, out: &mut Vec<MobEvent>) {
 /// mob that never sneaks. The phases themselves are
 /// `movement_restitution::restitute_movement`, the same port the player and
 /// dropped items use.
-struct MobRestitution<'a, 'w> {
+struct MobRestitution<'a> {
     mob: &'a mut Mob,
-    world: &'a MobWorld<'w>,
+    world: &'a crate::world::World,
+    movement: &'a horizon_world::movement_properties::BoundMovementProperties,
 }
-impl<'a, 'w> MobRestitution<'a, 'w> {
+impl<'a> MobRestitution<'a> {
     /// The block's movement data: its coefficients and its bounce tag.
     fn movement(
         &self,
         state: BlockStateId,
     ) -> Result<horizon_world::movement_properties::MovementBlock, ()> {
-        self.world.movement.get(state).map_err(|_| ())
+        self.movement.get(state).map_err(|_| ())
     }
 }
-impl RestitutionWorld for MobRestitution<'_, '_> {
+impl RestitutionWorld for MobRestitution<'_> {
     // The block data cannot fail here: a state the registry does not know
     // reads as a block with no bounce, never as an error.
     type Error = ();
@@ -2162,7 +2171,7 @@ impl RestitutionWorld for MobRestitution<'_, '_> {
                 position.z.floor() as i32,
             ));
         };
-        let state = self.world.world.block(support[0], support[1], support[2]);
+        let state = self.world.block(support[0], support[1], support[2]);
         let keeps_column = self
             .movement(state)
             .is_ok_and(|b| b.wall || b.coefficients.fence_gate);

crates/horizon-client/src/mobs/random_textures.rs

@@ -1,5 +1,5 @@
 //! OptiFine random entity textures on mobs: which variant of each of its textures a mob wears
-//! (`horizon_optifine::random_textures` finds them in the packs).
+//! (the pack formats find them in the packs: [`crate::entity_textures`]).
 //!
 //! [`choose`] runs when the client first sees a mob, about once a second after that, and on the
 //! next tick when the mob draws a texture with rules it hasn't chosen for (a wolf just tamed;
@@ -16,8 +16,7 @@
 
 use super::render::{DYE_NAMES, PROFESSIONS};
 use super::{Mob, MobData, Species};
-use horizon_optifine::random::{self, Block, Facts, Weather};
-use horizon_optifine::random_textures::RandomTextures;
+use crate::entity_textures::{self as random, Block, Facts, RandomTextures, Weather};
 use std::sync::atomic::{AtomicBool, Ordering};
 
 /// Where the mob was when the client first saw it.
@@ -41,7 +40,7 @@ pub struct Choice {
     /// The [`RandomTextures::generation`] the picks are from: another (a pack reload) makes
     /// them stale.
     generation: u64,
-    /// The variant each rule file chose, by its index in [`RandomTextures::rules`].
+    /// The variant each rule file chose, by its index ([`RandomTextures::matching`]).
     picks: Vec<(usize, u32)>,
     /// The body texture's variant.
     primary: Option<u32>,
@@ -176,7 +175,7 @@ pub fn choose(
                 Some(&(_, index)) => index,
                 None => {
                     // No rule matching is the texture itself, as is ETF's 0.
-                    let index = textures.rules(id).matching(&facts, seed).unwrap_or(0);
+                    let index = textures.matching(id, &facts, seed).unwrap_or(0);
                     choice.picks.push((id, index));
                     index
                 }
@@ -301,7 +300,8 @@ mod tests {
             std::fs::create_dir_all(path.parent().unwrap()).unwrap();
             std::fs::write(path, text).unwrap();
         }
-        let textures = RandomTextures::scan(&root);
+        crate::pack_formats::install();
+        let textures = crate::entity_textures::EntityTextures::load(&root).random;
         let _ = std::fs::remove_dir_all(&root);
         textures
     }

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

@@ -2351,7 +2351,7 @@ pub fn part_matrix(
         .find_map(|c| part_matrix(c, m, poses, name, x_offset))
 }
 /// The first part named `name`, depth first.
-pub(super) fn find_part<'a>(part: &'a Part, name: &str) -> Option<&'a Part> {
+pub fn find_part<'a>(part: &'a Part, name: &str) -> Option<&'a Part> {
     if part.name == name {
         return Some(part);
     }
@@ -3640,7 +3640,6 @@ mod scroll_tests {
 mod emissive_tests {
     use super::*;
     use crate::mobs::{Polygon, Species};
-    use horizon_optifine::{blink::Blinks, emissive::Emissive, random_textures::RandomTextures};
     use std::sync::{Arc, RwLock};
 
     /// A silverfish (drawn with its type's texture) whose model is one quad.
@@ -3686,10 +3685,12 @@ mod emissive_tests {
             };
             std::fs::write(path, text).unwrap();
         }
-        let random = RandomTextures::scan(&root);
-        let blinks = Blinks::scan(&root, &random);
-        let mut emissive = Emissive::scan(&root, &random);
-        emissive.pair_beside(&root, blinks.files());
+        crate::pack_formats::install();
+        let crate::entity_textures::EntityTextures {
+            random,
+            blinks,
+            emissive,
+        } = crate::entity_textures::EntityTextures::load(&root);
         let _ = std::fs::remove_dir_all(&root);
         MobData {
             states: Vec::new(),
@@ -3869,7 +3870,7 @@ mod emissive_tests {
             blocks: Vec::new(),
             moon_phase: 0,
             day_time: 0,
-            weather: horizon_optifine::random::Weather::Clear,
+            weather: crate::entity_textures::Weather::Clear,
         };
         let props = format!("{RANDOM}/silverfish.properties");
         let variant = format!("{RANDOM}/silverfish2.png");
@@ -3931,7 +3932,6 @@ mod emissive_tests {
 mod random_texture_tests {
     use super::*;
     use crate::mobs::{Polygon, Species};
-    use horizon_optifine::random_textures::RandomTextures;
     use std::sync::{Arc, RwLock};
 
     /// A silverfish (drawn with its type's texture) whose model is one quad.
@@ -3967,7 +3967,8 @@ mod random_texture_tests {
         std::fs::create_dir_all(&dir).unwrap();
         std::fs::write(dir.join("silverfish.properties"), "textures.1=2").unwrap();
         std::fs::write(dir.join("silverfish2.png"), "").unwrap();
-        let random = RandomTextures::scan(&root);
+        crate::pack_formats::install();
+        let random = crate::entity_textures::EntityTextures::load(&root).random;
         let _ = std::fs::remove_dir_all(&root);
         MobData {
             states: Vec::new(),
@@ -4004,7 +4005,7 @@ mod random_texture_tests {
                 blocks: Vec::new(),
                 moon_phase: 0,
                 day_time: 0,
-                weather: horizon_optifine::random::Weather::Clear,
+                weather: crate::entity_textures::Weather::Clear,
             };
             crate::mobs::random_textures::choose(&mut m, &textures, &data, Some(seen), 0);
         }

crates/horizon-client/src/mobs/villager_brain.rs

@@ -928,12 +928,12 @@ fn chunk_pois(
         return;
     };
     let kind = |state: u32| poi_of_state(w, horizon_world::registry::BlockStateId(state));
-    let min = w.world.bottom_y();
-    for s in (y0 - min) >> 4..=(y1 - min) >> 4 {
-        let section = &chunk.sections[s as usize];
-        for &(i, poi) in w.world.pois.get((qx, s, qz), section, kind).iter() {
+    let (min, mut lists) = (w.world.bottom_y(), Vec::new());
+    w.world.pois.column(chunk, min, (y0, y1), kind, &mut lists);
+    for (base, pois) in &lists {
+        for &(i, poi) in pois.iter() {
             let i = i32::from(i);
-            let y = min + s * 16 + (i >> 8);
+            let y = base + (i >> 8);
             if (y0..=y1).contains(&y) {
                 visit(poi, [qx * 16 + (i & 15), y, qz * 16 + (i >> 4 & 15)]);
             }

crates/horizon-client/src/multiplayer.rs

@@ -7,7 +7,6 @@ use crate::lan::discovery::Scanner;
 use crate::text::{DARK_GRAY, GRAY, Text, format_translation};
 use crate::title::confirm_top;
 use horizon_protocol::servers::{self, ServerEntry};
-pub use page::Form;
 use std::{
     collections::HashMap,
     path::{Path, PathBuf},
@@ -139,8 +138,6 @@ pub enum Screen {
         relay: String,
         focus: u8,
     },
-    /// A page a crate registered at the title screen's Friends icon, as a form.
-    Page(Form),
     Disconnected {
         reason: String,
         /// Auto-reconnect's next attempt, until it is cancelled.
@@ -149,21 +146,6 @@ pub enum Screen {
         lines: std::cell::Cell<usize>,
     },
 }
-mod page;
-
-/// What the title screen's Friends icon opens: the page a crate registered there
-/// (`Place::Title`), else Join a Friend when an invite code can be joined. None: it is inactive.
-pub fn title_entry() -> Option<Screen> {
-    match page::title_page() {
-        Some(page) => Some(Screen::Page(Form::open(page))),
-        None => crate::net::joins_friends().then(|| Screen::friend(true)),
-    }
-}
-/// Whether the title screen's Friends icon opens something ([`title_entry`]).
-pub fn has_title_entry() -> bool {
-    page::title_page().is_some() || crate::net::joins_friends()
-}
-
 /// What a click asks the title screen to do.
 pub enum Outcome {
     None,
@@ -194,7 +176,6 @@ impl Screen {
             Self::Direct { .. } => "direct_connect",
             Self::ConfirmDelete { .. } => "server_delete",
             Self::Friend { .. } => "friends_join",
-            Self::Page(form) => form.id(),
             Self::Disconnected { .. } => "disconnected",
         }
     }
@@ -763,7 +744,6 @@ impl Screen {
                     53,
                 ),
             ],
-            Self::Page(form) => form.buttons(w, h),
             Self::Friend { code, .. } => vec![
                 b(
                     half(w) - 100.0,
@@ -884,7 +864,6 @@ impl Screen {
                     ]),
                 )
             }
-            Self::Page(form) => form.narration(),
             Self::Friend { .. } => ScreenInfo::new(
                 "multiplayer/friend",
                 get("horizon.multiplayer.join_friend", "Join a Friend"),
@@ -1339,7 +1318,6 @@ impl Screen {
                     centered(batch, &line.plain(), top + 17.0 + i as f32 * 9.0, u32::MAX);
                 }
             }
-            Self::Page(form) => form.draw(atlas, batch, caret, focused_at),
             Self::Friend {
                 code, relay, focus, ..
             } => {
@@ -1405,7 +1383,6 @@ impl Screen {
     /// selected server or LAN game, as a click on it does.
     pub fn confirm(&self) -> Outcome {
         match self {
-            Self::Page(form) => form.confirm(),
             Self::Direct { address } if servers::parse_address(address).is_some() => {
                 Outcome::Connect {
                     address: direct_address(address),
@@ -1454,9 +1431,6 @@ impl Screen {
         saves: &Path,
     ) -> Outcome {
         let (w, h) = size;
-        if let Self::Page(form) = self {
-            return form.click(id, x, y);
-        }
         match (&mut *self, id) {
             (
                 Self::List {
@@ -1849,7 +1823,6 @@ impl Screen {
             Self::Friend { focus: 0, .. } => 64.0,
             Self::Friend { focus: 1, .. } => 105.0,
             Self::Friend { .. } => return None,
-            Self::Page(form) => return form.focused_box(),
             _ => return None,
         };
         Some([(w / 2.0).floor() - 100.0, y, 200.0, 20.0])
@@ -1878,13 +1851,6 @@ impl Screen {
             _ => None,
         }
     }
-    /// Whether a press off the buttons may land on one of its text fields.
-    pub fn has_fields(&self) -> bool {
-        matches!(
-            self,
-            Self::Edit { .. } | Self::Friend { .. } | Self::Page(_)
-        )
-    }
     /// Join a friend, with the relay the player set before.
     pub fn friend(from_title: bool) -> Self {
         Self::Friend {
@@ -1944,9 +1910,6 @@ impl Screen {
     }
     /// The focused text field, its id and maximum length (copy and paste).
     pub fn focused_text(&mut self) -> Option<(crate::clipboard::FieldId, &mut String, usize)> {
-        if let Self::Page(form) = self {
-            return form.focused_text();
-        }
         let id = match self {
             Self::Edit { focus: 0, .. } => SERVER_NAME,
             Self::Edit { .. } => SERVER_ADDRESS,
@@ -1971,9 +1934,6 @@ impl Screen {
     /// round to the first field. `button` is the focused button, if any; a field
     /// has the focus (`focus` below 2) only while no button does.
     pub fn tab_dir(&mut self, reverse: bool, buttons: &[u8], button: &mut Option<u8>) {
-        if let Self::Page(form) = self {
-            return form.tab_dir(reverse, buttons, button);
-        }
         let (Self::Edit { focus, .. } | Self::Friend { focus, .. }) = self else {
             return;
         };
@@ -2000,7 +1960,6 @@ impl Screen {
     pub fn escape(&mut self, saves: &Path) -> bool {
         match self {
             Self::List { .. }
-            | Self::Page(_)
             | Self::Friend {
                 from_title: true, ..
             } => true,

crates/horizon-client/src/multiplayer/page.rs

@@ -1,467 +0,0 @@
-//! A page a crate registers at `horizon_hooks::pages::Place::Title`, which the title screen's
-//! Friends icon opens: a form drawn as Join a Friend and `ManageServerScreen` are. The title at
-//! the top, then the rows from y 53 (a field's grey label, its 200-wide `EditBox` 11 below, the
-//! next 41 lower; text 10 a line), and the page's buttons in a column under them from a quarter
-//! of the height + 114, 24 apart, the one that leaves it last.
-//!
-//! The engine keeps each field's text while the form is open (the title screen's caret edits
-//! it, as every field of its own) and tells the page each change before anything else reaches
-//! it ([`Act::Edit`]), then Enter in a field ([`Act::Submit`]) and the presses. A page joins a
-//! server with `horizon_hooks::pages::connect`.
-use super::{ButtonSpec, Outcome, centered_x, half, quarter};
-use crate::hud::{HudAtlas, HudBatch, rgba};
-use horizon_hooks::pages::{self, Act, Page, Place, Row};
-use std::cell::RefCell;
-use std::time::Instant;
-
-/// The first button's id; button `k` of the page is `FIRST + k`.
-const FIRST: u8 = 100;
-/// The text a line of the form wraps at.
-const WIDTH: f32 = 300.0;
-
-/// The page the title screen's Friends icon opens: the first registered there.
-pub(super) fn title_page() -> Option<&'static dyn Page> {
-    pages::engine::all()
-        .iter()
-        .copied()
-        .find(|page| page.place() == Place::Title)
-}
-
-/// An open form: the page, and what the engine keeps while it is open.
-#[derive(Clone)]
-pub struct Form {
-    page: &'static dyn Page,
-    /// Each field's text, in the order the rows have them.
-    texts: Vec<String>,
-    /// The text the page last heard of each field.
-    sent: RefCell<Vec<String>>,
-    /// The focused field; `texts.len()` (or more) while a button has the focus.
-    pub(super) focus: usize,
-    /// Each field's box where the last draw put it.
-    boxes: RefCell<Vec<[f32; 4]>>,
-}
-
-impl std::fmt::Debug for Form {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        f.debug_struct("Form")
-            .field("page", &self.page.id())
-            .field("texts", &self.texts)
-            .field("focus", &self.focus)
-            .finish()
-    }
-}
-
-/// A button of the form: its row (None: the one that leaves), label key, and whether it acts.
-struct Button {
-    row: Option<usize>,
-    label: &'static str,
-    active: bool,
-    half: bool,
-}
-
-impl Form {
-    /// The form of `page`, its fields holding the text its rows start with, the first focused.
-    pub fn open(page: &'static dyn Page) -> Self {
-        let mut rows = Vec::new();
-        page.rows(&mut rows);
-        let texts: Vec<String> = rows
-            .iter()
-            .filter_map(|row| match row {
-                Row::Field { text, .. } => Some(text.clone()),
-                _ => None,
-            })
-            .collect();
-        Self {
-            page,
-            sent: RefCell::new(texts.clone()),
-            boxes: RefCell::new(vec![[0.0; 4]; texts.len()]),
-            texts,
-            focus: 0,
-        }
-    }
-
-    pub fn id(&self) -> &'static str {
-        self.page.id()
-    }
-
-    /// The page's rows, after it heard every change to its fields.
-    fn rows(&self) -> Vec<Row> {
-        let mut rows = Vec::new();
-        self.page.rows(&mut rows);
-        let fields = field_rows(&rows);
-        let mut sent = self.sent.borrow_mut();
-        let mut told = false;
-        for ((text, sent), row) in self.texts.iter().zip(sent.iter_mut()).zip(fields) {
-            if text != sent {
-                sent.clone_from(text);
-                self.page.act(row, Act::Edit(text.clone()));
-                told = true;
-            }
-        }
-        if told {
-            rows.clear();
-            self.page.rows(&mut rows);
-        }
-        rows
-    }
-
-    fn buttons_of(rows: &[Row], back: &'static str) -> Vec<Button> {
-        let mut buttons: Vec<Button> = rows
-            .iter()
-            .enumerate()
-            .filter_map(|(r, row)| match row {
-                Row::Button {
-                    label,
-                    active,
-                    half,
-                    ..
-                } => Some(Button {
-                    row: Some(r),
-                    label,
-                    active: *active,
-                    half: *half,
-                }),
-                _ => None,
-            })
-            .collect();
-        buttons.push(Button {
-            row: None,
-            label: back,
-            active: true,
-            half: false,
-        });
-        buttons
-    }
-
-    /// The id of the button that leaves: Cancel's or Done's, for the controller.
-    fn back_id(&self) -> u8 {
-        if self.page.back() == "gui.cancel" {
-            57
-        } else {
-            50
-        }
-    }
-
-    pub fn buttons(&self, w: f32, h: f32) -> Vec<ButtonSpec> {
-        let rows = self.rows();
-        let cx = half(w);
-        let mut y = quarter(h) + 114.0;
-        let mut beside = false;
-        let mut out = Vec::new();
-        for (k, b) in Self::buttons_of(&rows, self.page.back())
-            .into_iter()
-            .enumerate()
-        {
-            let id = match b.row {
-                Some(_) => FIRST + k as u8,
-                None => self.back_id(),
-            };
-            let label = crate::lang::get(b.label);
-            let (x, bw) = match (b.half, beside) {
-                (true, true) => {
-                    y -= 24.0;
-                    beside = false;
-                    (cx + 2.0, 98.0)
-                }
-                (true, false) => {
-                    beside = true;
-                    (cx - 100.0, 98.0)
-                }
-                (false, _) => {
-                    beside = false;
-                    (cx - 100.0, 200.0)
-                }
-            };
-            out.push((x, y, bw, label, b.active, id));
-            y += 24.0;
-        }
-        out
-    }
-
-    pub fn draw(
-        &self,
-        atlas: &HudAtlas,
-        batch: &mut HudBatch,
-        caret: &mut crate::ui::Caret,
-        focused_at: Instant,
-    ) {
-        let w = batch.width;
-        let rows = self.rows();
-        let title = crate::lang::get(self.page.title());
-        let tw = HudBatch::text_width(atlas, &title);
-        batch.text(atlas, &title, centered_x(w, tw), 20.0, u32::MAX, true);
-        let mut y = 53.0;
-        let mut field = 0;
-        let mut boxes = self.boxes.borrow_mut();
-        for (r, row) in rows.iter().enumerate() {
-            let (text, color) = match row {
-                Row::Field { label, max, .. } => {
-                    let Some(value) = self.texts.get(field) else {
-                        break;
-                    };
-                    super::Screen::field(
-                        atlas,
-                        batch,
-                        caret,
-                        focused_at,
-                        &crate::lang::get(label),
-                        value,
-                        ("page.field", r),
-                        *max,
-                        (y, y + 11.0),
-                        self.focus == field,
-                    );
-                    boxes[field] = [half(w) - 100.0, y + 11.0, 200.0, 20.0];
-                    field += 1;
-                    y += 41.0;
-                    continue;
-                }
-                Row::Space(px) => {
-                    y += f32::from(*px);
-                    continue;
-                }
-                Row::Heading(key) => (crate::lang::get(key), u32::MAX),
-                Row::Note(text) => (text.clone(), rgba(160, 160, 160, 255)),
-                Row::Text { text, quiet, .. } => {
-                    let grey = rgba(160, 160, 160, 255);
-                    (text.clone(), if *quiet { grey } else { u32::MAX })
-                }
-                _ => continue,
-            };
-            for line in super::wrap(&text, WIDTH, atlas) {
-                let lw = HudBatch::text_width(atlas, &line);
-                batch.text(atlas, &line, centered_x(w, lw), y, color, true);
-                y += 10.0;
-            }
-        }
-    }
-
-    pub fn narration(&self) -> crate::widgets::ScreenInfo {
-        crate::widgets::ScreenInfo::new(self.page.id(), crate::lang::get(self.page.title()))
-    }
-
-    /// A press on button `id`, or on a field (`id` None).
-    pub fn click(&mut self, id: Option<u8>, x: f32, y: f32) -> Outcome {
-        match id {
-            Some(id) if id == self.back_id() => Outcome::Back,
-            Some(id) if id >= FIRST => {
-                let rows = self.rows();
-                let buttons = Self::buttons_of(&rows, self.page.back());
-                match buttons.get(usize::from(id - FIRST)) {
-                    Some(Button {
-                        row: Some(r),
-                        active: true,
-                        ..
-                    }) => self.act(*r, Act::Press),
-                    _ => Outcome::None,
-                }
-            }
-            Some(_) => Outcome::None,
-            None => {
-                let hit = self
-                    .boxes
-                    .borrow()
-                    .iter()
-                    .position(|&[bx, by, bw, bh]| crate::ui::hovered((x, y), bx, by, bw, bh));
-                if let Some(field) = hit {
-                    self.focus = field;
-                }
-                Outcome::None
-            }
-        }
-    }
-
-    /// Enter: the focused field submits.
-    pub fn confirm(&self) -> Outcome {
-        let rows = self.rows();
-        match field_rows(&rows).nth(self.focus) {
-            Some(r) => self.act(r, Act::Submit),
-            None => Outcome::None,
-        }
-    }
-
-    /// The page acts; a server it asked to join is joined.
-    fn act(&self, row: usize, act: Act) -> Outcome {
-        self.page.act(row, act);
-        match pages::engine::take_connect() {
-            Some(address) => Outcome::Connect {
-                address,
-                lan: false,
-            },
-            None => Outcome::None,
-        }
-    }
-
-    pub fn focused_box(&self) -> Option<[f32; 4]> {
-        self.boxes.borrow().get(self.focus).copied()
-    }
-
-    /// The focused field, its id and maximum length.
-    pub fn focused_text(&mut self) -> Option<(crate::clipboard::FieldId, &mut String, usize)> {
-        let mut rows = Vec::new();
-        self.page.rows(&mut rows);
-        let (r, max) = rows
-            .iter()
-            .enumerate()
-            .filter_map(|(r, row)| match row {
-                Row::Field { max, .. } => Some((r, *max)),
-                _ => None,
-            })
-            .nth(self.focus)?;
-        let text = self.texts.get_mut(self.focus)?;
-        Some((("page.field", r), text, max))
-    }
-
-    /// Tab through the fields, then the enabled `buttons`, then round to the first field.
-    pub fn tab_dir(&mut self, reverse: bool, buttons: &[u8], button: &mut Option<u8>) {
-        let fields = self.texts.len();
-        let stops = fields + buttons.len();
-        if stops == 0 {
-            return;
-        }
-        let at = match *button {
-            Some(id) => buttons.iter().position(|&b| b == id).map(|i| fields + i),
-            None => Some(self.focus.min(fields.saturating_sub(1))),
-        }
-        .unwrap_or(0);
-        let next = if reverse {
-            (at + stops - 1) % stops
-        } else {
-            (at + 1) % stops
-        };
-        if next < fields {
-            self.focus = next;
-            *button = None;
-        } else {
-            self.focus = fields;
-            *button = Some(buttons[next - fields]);
-        }
-    }
-}
-
-/// The rows that are fields, in order.
-fn field_rows(rows: &[Row]) -> impl Iterator<Item = usize> + '_ {
-    rows.iter()
-        .enumerate()
-        .filter(|(_, row)| matches!(row, Row::Field { .. }))
-        .map(|(r, _)| r)
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use std::sync::Mutex;
-
-    /// A join form: a code and a relay, Join while the code has 4 characters or more.
-    struct Join {
-        heard: Mutex<Vec<(usize, Act)>>,
-        code: Mutex<String>,
-    }
-
-    impl Page for Join {
-        fn id(&self) -> &'static str {
-            "test.join"
-        }
-        fn title(&self) -> &'static str {
-            "horizon.multiplayer.join_friend"
-        }
-        fn place(&self) -> Place {
-            Place::Title
-        }
-        fn rows(&self, rows: &mut Vec<Row>) {
-            let code = self.code.lock().unwrap().clone();
-            rows.push(Row::field("horizon.multiplayer.invite_code", code.clone()).max(8));
-            rows.push(Row::field(
-                "horizon.multiplayer.relay",
-                "relay.example:25599",
-            ));
-            rows.push(Row::button("horizon.multiplayer.join").active(code.len() >= 4));
-        }
-        fn act(&self, row: usize, act: Act) {
-            if let (0, Act::Edit(text)) = (row, &act) {
-                text.clone_into(&mut self.code.lock().unwrap());
-            }
-            if matches!((row, &act), (2, Act::Press) | (0, Act::Submit)) {
-                pages::connect(format!("friend:{}", self.code.lock().unwrap()));
-            }
-            self.heard.lock().unwrap().push((row, act));
-        }
-        fn back(&self) -> &'static str {
-            "gui.cancel"
-        }
-    }
-
-    fn join() -> &'static Join {
-        Box::leak(Box::new(Join {
-            heard: Mutex::new(Vec::new()),
-            code: Mutex::new(String::new()),
-        }))
-    }
-
-    #[test]
-    fn a_form_lays_out_as_join_a_friend() {
-        let form = Form::open(join());
-        let buttons = form.buttons(427.0, 240.0);
-        // Join at a quarter of the height + 114, Cancel 24 below, both 200 wide and centred.
-        assert_eq!(
-            buttons
-                .iter()
-                .map(|(x, y, w, _, on, id)| (*x, *y, *w, *on, *id))
-                .collect::<Vec<_>>(),
-            [
-                (113.0, 174.0, 200.0, false, FIRST),
-                (113.0, 198.0, 200.0, true, 57)
-            ]
-        );
-        assert_eq!(form.texts, ["", "relay.example:25599"]);
-    }
-
-    #[test]
-    fn typing_reaches_the_page_before_a_press_and_enter_submits() {
-        let page = join();
-        let mut form = Form::open(page);
-        let (id, text, max) = form.focused_text().unwrap();
-        assert_eq!((id, max), (("page.field", 0), 8));
-        text.push_str("AB");
-        // Join is greyed: the page heard "AB" before the buttons were laid out.
-        assert!(!form.buttons(427.0, 240.0)[0].4);
-        form.focused_text().unwrap().1.push_str("CD");
-        assert!(form.buttons(427.0, 240.0)[0].4);
-        match form.click(Some(FIRST), 0.0, 0.0) {
-            Outcome::Connect { address, lan } => {
-                assert_eq!((address.as_str(), lan), ("friend:ABCD", false))
-            }
-            _ => panic!("Join did not connect"),
-        }
-        match form.confirm() {
-            Outcome::Connect { address, .. } => assert_eq!(address, "friend:ABCD"),
-            _ => panic!("Enter did not submit"),
-        }
-        let heard = page.heard.lock().unwrap();
-        assert_eq!(
-            *heard,
-            [
-                (0, Act::Edit("AB".into())),
-                (0, Act::Edit("ABCD".into())),
-                (2, Act::Press),
-                (0, Act::Submit)
-            ]
-        );
-        assert!(matches!(form.click(Some(57), 0.0, 0.0), Outcome::Back));
-    }
-
-    #[test]
-    fn tab_goes_through_the_fields_then_the_buttons() {
-        let mut form = Form::open(join());
-        let mut button = None;
-        form.tab_dir(false, &[57], &mut button);
-        assert_eq!((form.focus, button), (1, None));
-        form.tab_dir(false, &[57], &mut button);
-        assert_eq!((form.focus, button), (2, Some(57)));
-        form.tab_dir(false, &[57], &mut button);
-        assert_eq!((form.focus, button), (0, None));
-        form.tab_dir(true, &[57], &mut button);
-        assert_eq!(button, Some(57));
-        assert!(form.focused_text().is_none());
-    }
-}

crates/horizon-client/src/net.rs

@@ -523,22 +523,6 @@ pub fn is_invite(code: &str, full: bool) -> bool {
     horizon_hooks::engine::tunnel().is_some_and(|r| r.is_code(code, full))
 }
 
-/// Whether an invite code can be joined: a resolver is registered (horizon-official registers
-/// horizon-friends'). The title screen's Friends icon, which opens Join a Friend, is inactive
-/// without one, as the pause menu's is without a page to share from.
-pub fn joins_friends() -> bool {
-    #[cfg(test)]
-    if JOINS_FRIENDS_IN_TEST.get() {
-        return true;
-    }
-    horizon_hooks::engine::tunnel().is_some()
-}
-#[cfg(test)]
-thread_local! {
-    /// A test's stand-in for a registered resolver: the registry is the process's and sealed.
-    pub(crate) static JOINS_FRIENDS_IN_TEST: std::cell::Cell<bool> = const { std::cell::Cell::new(false) };
-}
-
 /// An address as players and logs see it: a friend's invite code stays
 /// out of it (its secret is in there).
 pub fn shown_address(address: &str) -> String {

crates/horizon-client/src/no_resources.rs

@@ -46,11 +46,11 @@ impl NoResources {
         let x = ((ui.w - width) / 2.0).round();
         let lines: Vec<Vec<String>> = PARAGRAPHS
             .iter()
-            .map(|p| wrap(ui, Face::Regular, BODY, p, width))
+            .map(|p| wrap(ui, Face::Regular, body(), p, width))
             .collect();
         let text_h = lines.iter().map(|l| l.len() as f32 * LINE).sum::<f32>()
             + (lines.len() - 1) as f32 * PARAGRAPH_GAP;
-        let height = TITLE_LINE + 16.0 + text_h + 28.0 + CONTROL + 20.0 + SMALL_LINE;
+        let height = TITLE_LINE + 16.0 + text_h + 28.0 + control() + 20.0 + SMALL_LINE;
         let y = ((ui.h - height) / 2.0).max(24.0).round();
         let buttons_y = y + TITLE_LINE + 16.0 + text_h + 28.0;
         let mut buttons = Vec::new();
@@ -59,7 +59,7 @@ impl NoResources {
             ("Download the launcher", Action::Download),
             ("Quit", Action::Quit),
         ] {
-            let w = (ui.measure(Face::Medium, BUTTON_TEXT, label) + 40.0).round();
+            let w = (ui.measure(Face::Medium, button_text(), label) + 40.0).round();
             buttons.push(Button {
                 label,
                 action,
@@ -80,21 +80,29 @@ impl NoResources {
 
     pub fn draw(&self, ui: &mut Ui) {
         let layout = self.layout(ui);
-        ui.rounded(0.0, 0.0, ui.w, ui.h, 0.0, color::BG);
+        ui.rounded(0.0, 0.0, ui.w, ui.h, 0.0, color::bg());
         let mut y = layout.y;
         ui.text_line(
             Face::Medium,
-            TITLE_SIZE,
+            title_size(),
             TITLE_LINE,
             layout.x,
             y,
-            color::TEXT,
+            color::text(),
             TITLE,
         );
         y += TITLE_LINE + 16.0;
         for paragraph in &layout.lines {
             for line in paragraph {
-                ui.text_line(Face::Regular, BODY, LINE, layout.x, y, color::TEXT, line);
+                ui.text_line(
+                    Face::Regular,
+                    body(),
+                    LINE,
+                    layout.x,
+                    y,
+                    color::text(),
+                    line,
+                );
                 y += LINE;
             }
             y += PARAGRAPH_GAP;
@@ -102,20 +110,20 @@ impl NoResources {
         for button in &layout.buttons {
             let hovered = button.contains(ui.cursor);
             let (plate, ink) = match (button.action, hovered) {
-                (Action::Download, false) => (color::ACCENT, color::ON_ACCENT),
+                (Action::Download, false) => (color::accent(), color::on_accent()),
                 (Action::Download, true) => {
-                    (color::with_alpha(color::ACCENT, 0.85), color::ON_ACCENT)
+                    (color::with_alpha(color::accent(), 0.85), color::on_accent())
                 }
-                (Action::Quit, false) => (color::RAISED, color::TEXT),
-                (Action::Quit, true) => (color::HOVER, color::TEXT),
+                (Action::Quit, false) => (color::raised(), color::text()),
+                (Action::Quit, true) => (color::hover(), color::text()),
             };
-            let h = CONTROL;
+            let h = control();
             ui.rounded(button.x, button.y, button.w, h, h / 2.0, plate);
-            let lw = ui.measure(Face::Medium, BUTTON_TEXT, button.label);
+            let lw = ui.measure(Face::Medium, button_text(), button.label);
             let lx = button.x + ((button.w - lw) / 2.0).round();
             ui.text_line(
                 Face::Medium,
-                BUTTON_TEXT,
+                button_text(),
                 h,
                 lx,
                 button.y,
@@ -123,11 +131,11 @@ impl NoResources {
                 button.label,
             );
         }
-        let small_y = layout.buttons[0].y + CONTROL + 20.0;
+        let small_y = layout.buttons[0].y + control() + 20.0;
         for (i, line) in wrap(
             ui,
             Face::Regular,
-            ui_theme::SMALL,
+            ui_theme::small(),
             &self.looked_in,
             layout.width,
         )
@@ -137,11 +145,11 @@ impl NoResources {
             let line_y = small_y + i as f32 * SMALL_LINE;
             ui.text_line(
                 Face::Regular,
-                ui_theme::SMALL,
+                ui_theme::small(),
                 SMALL_LINE,
                 layout.x,
                 line_y,
-                color::MUTED,
+                color::muted(),
                 line,
             );
         }
@@ -157,14 +165,22 @@ impl NoResources {
     }
 }
 
-const TITLE_SIZE: f32 = horizon_theme::TITLE.px;
+fn title_size() -> f32 {
+    ui_theme::sizes().title
+}
 const TITLE_LINE: f32 = 40.0;
-const BODY: f32 = horizon_theme::BODY.px;
+fn body() -> f32 {
+    ui_theme::sizes().body
+}
 const LINE: f32 = 24.0;
 const PARAGRAPH_GAP: f32 = 10.0;
-const BUTTON_TEXT: f32 = horizon_theme::UI.px;
+fn button_text() -> f32 {
+    ui_theme::sizes().ui
+}
 const SMALL_LINE: f32 = 18.0;
-const CONTROL: f32 = horizon_theme::CONTROL_LARGE;
+fn control() -> f32 {
+    ui_theme::sizes().control_large
+}
 
 struct Layout {
     x: f32,
@@ -184,7 +200,7 @@ struct Button {
 
 impl Button {
     fn contains(&self, (cx, cy): (f32, f32)) -> bool {
-        cx >= self.x && cx < self.x + self.w && cy >= self.y && cy < self.y + CONTROL
+        cx >= self.x && cx < self.x + self.w && cy >= self.y && cy < self.y + control()
     }
 }
 
@@ -232,7 +248,7 @@ mod tests {
         for size in [[1280, 720], [800, 600], [2560, 1440]] {
             let (download, quit, density) = with_ui(size, (0.0, 0.0), |ui| {
                 let layout = screen.layout(ui);
-                let center = |b: &Button| (b.x + b.w / 2.0, b.y + CONTROL / 2.0);
+                let center = |b: &Button| (b.x + b.w / 2.0, b.y + control() / 2.0);
                 (
                     center(&layout.buttons[0]),
                     center(&layout.buttons[1]),
@@ -255,7 +271,7 @@ mod tests {
                 let layout = screen.layout(ui);
                 let last = layout.buttons.last().unwrap();
                 assert!(
-                    last.x + last.w <= ui.w && last.y + CONTROL <= ui.h,
+                    last.x + last.w <= ui.w && last.y + control() <= ui.h,
                     "{size:?}"
                 );
             });
@@ -266,10 +282,10 @@ mod tests {
     fn text_wraps_within_the_column_and_keeps_every_word() {
         with_ui([1280, 720], (0.0, 0.0), |ui| {
             for paragraph in PARAGRAPHS {
-                let lines = wrap(ui, Face::Regular, BODY, paragraph, 300.0);
+                let lines = wrap(ui, Face::Regular, body(), paragraph, 300.0);
                 assert!(lines.len() > 1, "{paragraph}");
                 for line in &lines {
-                    assert!(ui.measure(Face::Regular, BODY, line) <= 300.0, "{line}");
+                    assert!(ui.measure(Face::Regular, body(), line) <= 300.0, "{line}");
                 }
                 assert_eq!(lines.join(" "), paragraph);
             }

crates/horizon-client/src/osk.rs

@@ -293,16 +293,16 @@ impl Keyboard {
             y0 - 12.0,
             width + 24.0,
             height,
-            ui_theme::RADIUS_PLATE,
-            color::with_alpha(color::BG, 0.94),
+            ui_theme::radius_plate(),
+            color::with_alpha(color::bg(), 0.94),
         );
         ui.border(
             x0 - 12.0,
             y0 - 12.0,
             width + 24.0,
             height,
-            ui_theme::RADIUS_PLATE,
-            color::BORDER,
+            ui_theme::radius_plate(),
+            color::border(),
         );
         for (r, row) in self.rows().iter().enumerate() {
             let y = y0 + r as f32 * (KEY_H + GAP);
@@ -314,13 +314,13 @@ impl Keyboard {
                 let lit = matches!(key, Key::Shift) && (self.shift || self.caps)
                     || matches!(key, Key::Layer) && self.symbols;
                 let (plate, ink) = if focused {
-                    (color::ACCENT, color::ON_ACCENT)
+                    (color::accent(), color::on_accent())
                 } else if lit {
-                    (color::HOVER, color::TEXT)
+                    (color::hover(), color::text())
                 } else {
-                    (color::RAISED, color::TEXT)
+                    (color::raised(), color::text())
                 };
-                ui.rounded(x, y, w, KEY_H, ui_theme::RADIUS, plate);
+                ui.rounded(x, y, w, KEY_H, ui_theme::radius(), plate);
                 let label = match key {
                     Key::Char(ch) => self.letter(*ch),
                     Key::Shift if self.caps => "CAPS".into(),
@@ -331,10 +331,10 @@ impl Keyboard {
                     Key::Backspace => tr("horizon.osk.delete", "Delete"),
                     Key::Done => tr("gui.done", "Done"),
                 };
-                let lw = ui.measure(Face::Medium, ui_theme::BODY, &label);
+                let lw = ui.measure(Face::Medium, ui_theme::body(), &label);
                 ui.text_line(
                     Face::Medium,
-                    ui_theme::BODY,
+                    ui_theme::body(),
                     KEY_H,
                     x + ((w - lw) / 2.0).round(),
                     y,
@@ -359,10 +359,10 @@ impl Keyboard {
             .collect();
         ui.text_centered(
             Face::Regular,
-            ui_theme::SMALL,
+            ui_theme::small(),
             x0 + width / 2.0,
             y0 + 5.0 * (KEY_H + GAP) + 2.0,
-            color::MUTED,
+            color::muted(),
             &line.join("   "),
         );
     }

crates/horizon-client/src/studio/timeline_ui.rs

@@ -408,7 +408,7 @@ impl TimelineUi {
             let tx = start_x + sec * px_per_sec;
             if tx <= start_x + w {
                 // Major tick line
-                style::fill(batch, atlas, [tx, y + 8.0, 1.0, 8.0], style::HEAD_RULE);
+                style::fill(batch, atlas, [tx, y + 8.0, 1.0, 8.0], style::head_rule());
                 // Label every 2 or 5 seconds depending on width
                 let is_labeled = if total_secs > 60.0 {
                     (sec as u32).is_multiple_of(10)
@@ -424,7 +424,7 @@ impl TimelineUi {
                         "horizon.studio.timeline.seconds",
                         &[Text::literal(seconds)],
                     );
-                    batch.text_styled(atlas, &label, tx + 2.0, y + 1.0, style::SOFT, true);
+                    batch.text_styled(atlas, &label, tx + 2.0, y + 1.0, style::soft(), true);
                 }
             }
             sec += sec_step;
@@ -459,7 +459,7 @@ impl TimelineUi {
         // Base lane well
         let lane_rect = [start_x, y, track_w, bar_h];
         style::fill(batch, atlas, lane_rect, 0xFF14_171F);
-        style::ring(batch, atlas, lane_rect, style::ROW_RULE);
+        style::ring(batch, atlas, lane_rect, style::row_rule());
 
         let total_dur = self.duration_ms.max(1) as f32;
 
@@ -514,7 +514,7 @@ impl TimelineUi {
                     &scene_title,
                     seg_x + 5.0,
                     y + 5.0,
-                    style::MUTED,
+                    style::muted(),
                     true,
                 );
             }
@@ -577,7 +577,7 @@ impl TimelineUi {
         let px = start_x + norm * track_w;
 
         // Scrubber line from ruler through bottom of tracks
-        style::fill(batch, atlas, [px - 1.0, y, 2.0, h], style::ACCENT);
+        style::fill(batch, atlas, [px - 1.0, y, 2.0, h], style::accent());
 
         // Inverted triangle marker at ruler top
         let tri_color = style::WHITE;

crates/horizon-client/src/studio/topbar.rs

@@ -178,7 +178,7 @@ impl TopBarUi {
                 );
             }
             let color = if open {
-                style::ACCENT
+                style::accent()
             } else if hovered {
                 style::WHITE
             } else {
@@ -220,7 +220,7 @@ impl TopBarUi {
             if pause_hovered {
                 style::WHITE
             } else {
-                style::MUTED
+                style::muted()
             },
             true,
         );
@@ -339,7 +339,11 @@ impl TopBarUi {
                 &Text::translate(key, &[]),
                 x + 8.0,
                 y + 6.0,
-                if hovered { style::WHITE } else { style::MUTED },
+                if hovered {
+                    style::WHITE
+                } else {
+                    style::muted()
+                },
                 true,
             );
             if !shortcut.is_empty() {
@@ -350,7 +354,7 @@ impl TopBarUi {
                     &shortcut,
                     x + menu_width - shortcut_width - 8.0,
                     y + 6.0,
-                    style::SOFT,
+                    style::soft(),
                     true,
                 );
             }

crates/horizon-client/src/title.rs

@@ -1940,8 +1940,8 @@ impl Title {
                     )
                     .does(crate::widgets::Action::Exit),
                 ];
-                // CommonButtons' icon buttons: vanilla's Friends button opens a crate's page or
-                // Join a Friend, inactive with neither (`multiplayer::title_entry`).
+                // CommonButtons' icon buttons; Horizon's Join a Friend (an
+                // invite code) sits behind vanilla's Friends button.
                 for (i, (key, plain, id, icon)) in [
                     ("gui.friends.open", "Friends", 5, "friends/friends"),
                     ("options.language", "Language...", 6, "icon/language"),
@@ -1960,7 +1960,7 @@ impl Title {
                         y + 72.0,
                         20.0,
                         &lang::get_or(key, plain),
-                        id != 5 || crate::multiplayer::has_title_entry(),
+                        true,
                         id,
                     );
                     button.icon = Some((icon, 15.0));
@@ -3658,7 +3658,12 @@ Would you like to enable the Narrator or visit the Accessibility Settings?",
             .map(|b| b.id);
         if hit.is_some() {
             self.focused_button = hit;
-        } else if matches!(&self.mode, Mode::Multiplayer(screen) if screen.has_fields()) {
+        } else if matches!(
+            self.mode,
+            Mode::Multiplayer(
+                crate::multiplayer::Screen::Edit { .. } | crate::multiplayer::Screen::Friend { .. }
+            )
+        ) {
             // A press on a text field takes the focus from the button.
             self.focused_button = None;
         }
@@ -3777,7 +3782,7 @@ Would you like to enable the Narrator or visit the Accessibility Settings?",
                 crate::multiplayer::Outcome::None => Action::None,
             },
             (Mode::Main, Some(5)) => {
-                self.mode = crate::multiplayer::title_entry().map_or(Mode::Main, Mode::Multiplayer);
+                self.mode = Mode::Multiplayer(crate::multiplayer::Screen::friend(true));
                 Action::None
             }
             (Mode::Onboarding(_), Some(onboarding::SOUNDS)) => Action::Sounds,
@@ -5301,8 +5306,6 @@ mod classic_tests {
 
     #[test]
     fn classic_main_menu_icons_route_language_and_accessibility() {
-        // Join a Friend needs a resolver (title/tests.rs tests the icon without one).
-        crate::net::JOINS_FRIENDS_IN_TEST.set(true);
         let mut title = Title::new(
             PathBuf::new(),
             Path::new("/nonexistent/horizon-test-resources"),

crates/horizon-client/src/title/tests.rs

@@ -100,61 +100,13 @@ impl Drop for Fixture {
     }
 }
 
-/// Join a Friend needs a resolver; these tests stand one in (`net::JOINS_FRIENDS_IN_TEST`).
-fn with_resolver() -> Fixture {
-    crate::net::JOINS_FRIENDS_IN_TEST.set(true);
-    Fixture::new()
-}
-
-#[test]
-fn without_a_resolver_the_friends_icon_is_inactive_and_opens_nothing() {
-    crate::net::JOINS_FRIENDS_IN_TEST.set(false);
-    let mut f = Fixture::new();
-    let icons: Vec<_> = f
-        .title
-        .buttons(480.0, 262.0)
-        .into_iter()
-        .filter(|b| b.icon.is_some())
-        .map(|b| (b.label.clone(), b.enabled, b.x))
-        .collect();
-    // Same place and look as with one, only greyed; Language and Accessibility stay active.
-    let friends = icons.iter().find(|(label, ..)| label == "Friends").unwrap();
-    assert!(!friends.1);
-    assert!(
-        icons
-            .iter()
-            .filter(|(label, ..)| label != "Friends")
-            .all(|(_, on, _)| *on)
-    );
-    assert_eq!(f.click("Friends"), Action::None);
-    assert!(matches!(f.title.mode, Mode::Main));
-    crate::net::JOINS_FRIENDS_IN_TEST.set(true);
-    let with: Vec<_> = f
-        .title
-        .buttons(480.0, 262.0)
-        .into_iter()
-        .filter(|b| b.icon.is_some())
-        .map(|b| (b.label.clone(), b.x, b.y))
-        .collect();
-    assert_eq!(
-        with.iter()
-            .map(|(l, x, _)| (l.clone(), *x))
-            .collect::<Vec<_>>(),
-        icons
-            .iter()
-            .map(|(l, _, x)| (l.clone(), *x))
-            .collect::<Vec<_>>()
-    );
-    crate::net::JOINS_FRIENDS_IN_TEST.set(false);
-}
-
 mod multiplayer_parent_navigation {
     use super::*;
     use crate::multiplayer::{Outcome, Screen};
 
     #[test]
     fn friend_cancel_returns_to_title() {
-        let mut f = with_resolver();
+        let mut f = Fixture::new();
         f.click("Friends");
         assert!(matches!(
             f.title.mode,
@@ -166,7 +118,7 @@ mod multiplayer_parent_navigation {
 
     #[test]
     fn friend_escape_returns_to_title() {
-        let mut f = with_resolver();
+        let mut f = Fixture::new();
         f.click("Friends");
         assert!(matches!(
             f.title.mode,

crates/horizon-client/src/ui_theme.rs

@@ -1,6 +1,6 @@
-//! The design system's widgets drawn in the game (`crates/horizon-theme`:
-//! palette, type scale, radii, control sizes, motion and the bundled fonts;
-//! `docs/design-system.md`). Every menu is vanilla's (`ui`); what is left
+//! The design system's widgets drawn in the game: palette, type scale, radii,
+//! control sizes and fonts from `menu_style`, given at startup (in the official
+//! game `crates/horizon-theme`, `docs/design-system.md`). Every menu is vanilla's (`ui`); what is left
 //! here draws Horizon's own overlays that vanilla has no screen for: the
 //! on-screen keyboard a controller types with (`osk`), plus the
 //! `horizon.txt` preferences.
@@ -39,44 +39,76 @@ pub(crate) fn set_preference(dir: &Path, key: &str, value: Option<&str>) {
     let _ = std::fs::write(dir.join("horizon.txt"), out);
 }
 
-/// The dark palette (`horizon_theme::DARK`) in the HUD's colour encoding, plus the
+/// The overlays' palette (`menu_style`) in the HUD's colour encoding, plus the
 /// translucent plates the overlays draw over the game.
 pub(crate) mod color {
-    use horizon_theme::DARK as P;
-    pub const fn hex(c: u32, a: u8) -> u32 {
-        (a as u32) << 24 | (c & 0xff) << 16 | (c >> 8 & 0xff) << 8 | (c >> 16 & 0xff)
+    use horizon_client_render::menu_style::{self, OverlayColours};
+    pub use menu_style::hud_colour as hex;
+    fn p() -> &'static OverlayColours {
+        &menu_style::get().overlay
     }
     /// The page, under every veil.
-    pub const BG: u32 = hex(P.page, 255);
+    pub fn bg() -> u32 {
+        hex(p().page, 255)
+    }
     /// Hover plates, secondary buttons, fields, the segmented track: the
     /// dark palette's soft plate, as ink over the veil so the plates read the
     /// same over any backdrop (over the page colour they are `plate_soft`).
-    pub const RAISED: u32 = hex(P.ink, 20);
+    pub fn raised() -> u32 {
+        hex(p().ink, 20)
+    }
     /// Pressed plates and a switch that is off (`plate`, the same way).
-    pub const HOVER: u32 = hex(P.ink, 36);
+    pub fn hover() -> u32 {
+        hex(p().ink, 36)
+    }
     /// One-pixel rules between rows, slider tracks.
-    pub const BORDER: u32 = hex(P.rule, 255);
+    pub fn border() -> u32 {
+        hex(p().rule, 255)
+    }
     /// Text and selection (`ink`).
-    pub const TEXT: u32 = hex(P.ink, 255);
+    pub fn text() -> u32 {
+        hex(p().ink, 255)
+    }
     /// Values and secondary text (`ink_soft`).
-    pub const MUTED: u32 = hex(P.ink_soft, 255);
-    pub const ACCENT: u32 = hex(P.accent, 255);
-    pub const ON_ACCENT: u32 = hex(P.on_accent, 255);
+    pub fn muted() -> u32 {
+        hex(p().ink_soft, 255)
+    }
+    pub fn accent() -> u32 {
+        hex(p().accent, 255)
+    }
+    pub fn on_accent() -> u32 {
+        hex(p().on_accent, 255)
+    }
     pub(crate) fn with_alpha(c: u32, a: f32) -> u32 {
         let base = (c >> 24) as f32;
         (c & 0x00ff_ffff) | ((base * a.clamp(0.0, 1.0)).round() as u32) << 24
     }
 }
 
-/// The launcher's type scale and shapes (`horizon_theme`), in dp.
-pub(crate) const SMALL: f32 = horizon_theme::CAPTION.px;
-pub(crate) const BODY: f32 = horizon_theme::LABEL.px;
-/// The boot screen's wordmark (`DISPLAY`) and console lines (`MICRO`).
-pub(crate) const DISPLAY: f32 = horizon_theme::DISPLAY.px;
-pub(crate) const MICRO: f32 = horizon_theme::MICRO.px;
-/// Fields; plates (hover rows, selection); pills (buttons, segments).
-pub(crate) const RADIUS: f32 = horizon_theme::RADIUS;
-pub(crate) const RADIUS_PLATE: f32 = horizon_theme::RADIUS_PLATE;
+/// The type scale and shapes (`menu_style`), in dp.
+pub(crate) fn sizes() -> &'static horizon_client_render::menu_style::Sizes {
+    &horizon_client_render::menu_style::get().sizes
+}
+pub(crate) fn small() -> f32 {
+    sizes().caption
+}
+pub(crate) fn body() -> f32 {
+    sizes().label
+}
+/// The boot screen's wordmark (`display`) and console lines (`micro`).
+fn display() -> f32 {
+    sizes().display
+}
+fn micro() -> f32 {
+    sizes().micro
+}
+/// Fields; plates (hover rows, selection).
+pub(crate) fn radius() -> f32 {
+    sizes().radius
+}
+pub(crate) fn radius_plate() -> f32 {
+    sizes().radius_plate
+}
 
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
 pub(crate) enum Face {
@@ -87,20 +119,34 @@ pub(crate) enum Face {
     /// Counts, timestamps and the boot screen's console lines.
     Mono,
 }
+#[cfg(not(test))]
+const TEST_FONTS: Option<horizon_client_render::menu_style::Fonts> = None;
+#[cfg(test)]
+const TEST_FONTS: Option<horizon_client_render::menu_style::Fonts> =
+    Some(horizon_client_render::menu_style::Fonts {
+        regular: horizon_theme::fonts::GEIST_REGULAR,
+        medium: horizon_theme::fonts::GEIST_MEDIUM,
+        semibold: horizon_theme::fonts::GEIST_SEMIBOLD,
+        mono: horizon_theme::fonts::GEIST_MONO,
+    });
 struct Fonts {
     faces: [FontRef<'static>; 4],
 }
 impl Fonts {
-    fn load() -> Self {
-        let f = |b: &'static [u8]| FontRef::try_from_slice(b).expect("bundled font");
-        Self {
+    /// The faces given in `menu_style`; none given, none (unit tests take the design system's).
+    fn load() -> Option<Self> {
+        let given = horizon_client_render::menu_style::get()
+            .fonts
+            .or(TEST_FONTS)?;
+        let f = |b: &'static [u8]| FontRef::try_from_slice(b).expect("given font");
+        Some(Self {
             faces: [
-                f(horizon_theme::fonts::GEIST_REGULAR),
-                f(horizon_theme::fonts::GEIST_MEDIUM),
-                f(horizon_theme::fonts::GEIST_SEMIBOLD),
-                f(horizon_theme::fonts::GEIST_MONO),
+                f(given.regular),
+                f(given.medium),
+                f(given.semibold),
+                f(given.mono),
             ],
-        }
+        })
     }
     fn face(&self, f: Face) -> &FontRef<'static> {
         &self.faces[f as usize]
@@ -142,7 +188,8 @@ struct Cached {
 }
 /// Glyphs and corner masks rasterized into the atlas region `horizon/ui-text`.
 struct Cache {
-    fonts: Fonts,
+    /// None: no fonts were given, and text draws nothing.
+    fonts: Option<Fonts>,
     entries: HashMap<Key, Cached>,
     shelf: (u32, u32, u32),
     pending: Vec<crate::font::Patch>,
@@ -230,9 +277,16 @@ impl Cache {
         if let Some(c) = self.entries.get(&key) {
             return *c;
         }
-        let scale = self.fonts.scale(face, f32::from(size) / 4.0);
+        let Some(fonts) = &self.fonts else {
+            return Cached {
+                rect: None,
+                left: 0.0,
+                top: 0.0,
+            };
+        };
+        let scale = fonts.scale(face, f32::from(size) / 4.0);
         let glyph = id.with_scale_and_position(scale, ab_glyph::point(0.0, 0.0));
-        let made = match self.fonts.face(face).outline_glyph(glyph) {
+        let made = match fonts.face(face).outline_glyph(glyph) {
             Some(outline) => {
                 let b = outline.px_bounds();
                 let (w, h) = (b.width() as u32, b.height() as u32);
@@ -459,14 +513,17 @@ impl<'a> Ui<'a> {
         let atlas = self.atlas;
         let gui = self.scale;
         with_cache(atlas, |c| {
-            let scale = c.fonts.scale(face, px);
+            let Some(fonts) = &c.fonts else {
+                return (0.0, 0.0, 0.0, Vec::new());
+            };
+            let scale = fonts.scale(face, px);
             let (ascent, descent) = {
-                let f = c.fonts.face(face).as_scaled(scale);
+                let f = fonts.face(face).as_scaled(scale);
                 (f.ascent(), f.descent())
             };
             let chars: Vec<(char, Option<crate::font::Glyph>)> = unformatted(text)
                 .map(|ch| {
-                    let pack = (!ch.is_whitespace() && c.fonts.face(face).glyph_id(ch).0 == 0)
+                    let pack = (!ch.is_whitespace() && fonts.face(face).glyph_id(ch).0 == 0)
                         .then(|| atlas.font.glyph(ch))
                         // The pack lacks it too (its missing glyph): Geist's box, like vanilla's.
                         .filter(|g| g.rect.is_some() || g.right <= 0.0);
@@ -491,7 +548,10 @@ impl<'a> Ui<'a> {
                     continue;
                 }
                 let (id, advance, kern) = {
-                    let font = c.fonts.face(face);
+                    let Some(fonts) = &c.fonts else {
+                        break;
+                    };
+                    let font = fonts.face(face);
                     let id = font.glyph_id(ch);
                     let f = font.as_scaled(scale);
                     (id, f.h_advance(id), prev.map_or(0.0, |p| f.kern(p, id)))
@@ -606,8 +666,8 @@ pub fn draw_boot(atlas: &HudAtlas, batch: &mut HudBatch, logs: &[String]) {
 /// The wordmark with its tagline, centred.
 fn wordmark(atlas: &HudAtlas, batch: &mut HudBatch) {
     let mut ui = Ui::new(atlas, batch, (0.0, 0.0));
-    let size = (ui.w / 16.0).clamp(DISPLAY, 96.0);
-    let small = (size * 0.25).clamp(MICRO, 18.0);
+    let size = (ui.w / 16.0).clamp(display(), 96.0);
+    let small = (size * 0.25).clamp(micro(), 18.0);
     let block = size * 1.45 + small * 0.6 + small * 1.5;
     let top = (ui.h - block) / 2.0;
     ui.text_centered(Face::SemiBold, size, ui.w / 2.0, top, BOOT_TEXT, "Horizon");
@@ -629,7 +689,7 @@ pub fn draw_boot_log(atlas: &HudAtlas, batch: &mut HudBatch, logs: &[String]) {
         return;
     }
     let mut ui = Ui::new(atlas, batch, (0.0, 0.0));
-    let (size, line, pad) = (MICRO, MICRO * 1.5, 16.0);
+    let (size, line, pad) = (micro(), micro() * 1.5, 16.0);
     let max_w = ui.w / 2.0;
     let max_rows = (((ui.h - pad) / line) as usize).clamp(1, 24);
     let mut y = ui.h - pad - line;
@@ -696,7 +756,12 @@ mod tests {
         let atlas = HudAtlas::build(Path::new("/nonexistent/horizon-test-assets")).unwrap();
         reset_atlas();
         let draw = |cache: &mut Cache| {
-            let glyph = cache.fonts.face(Face::Regular).glyph_id('A');
+            let glyph = cache
+                .fonts
+                .as_ref()
+                .unwrap()
+                .face(Face::Regular)
+                .glyph_id('A');
             assert!(
                 cache
                     .glyph(&atlas, Face::Regular, glyph, 16.0)
@@ -782,7 +847,7 @@ mod tests {
         let lines = wrapping_lines(
             &ui,
             Face::Mono,
-            MICRO,
+            micro(),
             "the quick brown fox jumps over the lazy dog",
             90.0,
         );
@@ -790,7 +855,7 @@ mod tests {
         assert!(
             lines
                 .iter()
-                .all(|l| ui.measure(Face::Mono, MICRO, l) <= 90.0),
+                .all(|l| ui.measure(Face::Mono, micro(), l) <= 90.0),
             "every wrapped line fits"
         );
         assert_eq!(
@@ -812,7 +877,7 @@ mod tests {
     fn drawn(atlas: &HudAtlas, text: &str) -> (f32, Vec<([f32; 2], [f32; 2])>) {
         let mut batch = HudBatch::new([1280, 720]);
         let mut ui = Ui::new(atlas, &mut batch, (0.0, 0.0));
-        let w = ui.text_line(Face::Medium, BODY, 20.0, 10.0, 10.0, color::TEXT, text);
+        let w = ui.text_line(Face::Medium, body(), 20.0, 10.0, 10.0, color::text(), text);
         let quads = batch
             .vertices
             .iter()

crates/horizon-discord/Cargo.toml

@@ -0,0 +1,15 @@
+[package]
+name = "horizon-discord"
+version = "0.1.0"
+edition.workspace = true
+license.workspace = true
+rust-version.workspace = true
+description = "Discord Rich Presence: \"Playing Horizon\" on the player's Discord profile (docs/native-client.md)"
+
+[dependencies]
+horizon-platform = { path = "../horizon-platform" }
+log = "0.4"
+serde_json = "1.0.151"
+
+[lints]
+workspace = true

crates/horizon-discord/src/lib.rs

@@ -1,11 +1,15 @@
 //! Discord Rich Presence: "Playing Horizon" on the player's Discord profile, with what they are
 //! doing (docs/native-client.md). A thread of its own talks to the Discord app on this computer
 //! through its local IPC socket (Discord's RPC docs: `discord-ipc-N`, frames of opcode u32 LE +
-//! length u32 LE + JSON). The game only calls [`set`] each frame: a change wakes the thread,
+//! length u32 LE + JSON). The game says what the player does on each change ([`set`]), which wakes the thread,
 //! which connects when Discord runs, retries every 15 s when it doesn't, keeps under Discord's
 //! update limit and clears the activity on quit. Nothing is sent with the setting off,
-//! or with `HORIZON_NO_DISCORD=1`. It uses nothing else of the game (docs/layers.md: Horizon layer):
-//! `game/discord.rs` says what the player does.
+//! or with `HORIZON_NO_DISCORD=1`.
+//!
+//! A Horizon crate (docs/layers.md): the game tells it what the player does through the
+//! platform's hooks ([`HOOKS`]: `client_started`, `activity`, `shutdown`), which the official
+//! executable (`horizon-official`) registers. horizon-client's own executable has no presence.
+#![forbid(unsafe_code)]
 use std::collections::VecDeque;
 use std::io::{self, Read, Write};
 use std::path::PathBuf;
@@ -15,7 +19,7 @@ use std::time::{Duration, Instant, SystemTime, UNIX_EPOCH};
 
 use serde_json::{Value, json};
 
-use horizon_command::args::GameMode;
+use horizon_platform::hooks::{self, Activity, Dimension, GameMode, Hooks, Play};
 
 /// The "Horizon" application on Discord's developer portal (public: it names the game). Its
 /// Rich Presence assets: `horizon`, the logo.
@@ -40,24 +44,38 @@ const CLOSE: u32 = 2;
 const PING: u32 = 3;
 const PONG: u32 = 4;
 
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
-pub enum Dimension {
-    Overworld,
-    Nether,
-    End,
-}
+/// The presence's hooks, for `horizon_platform::hooks::register`.
+pub static HOOKS: Presence = Presence;
 
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
-pub enum Play {
-    Singleplayer,
-    /// A server or someone else's LAN world. Its address and name are never shown.
-    Multiplayer,
-    /// This world is open to LAN or friends; `players` counts the host, `max` is how many
-    /// may join.
-    Hosting {
-        players: usize,
-        max: usize,
-    },
+pub struct Presence;
+
+impl Hooks for Presence {
+    /// Starts the presence thread with the game's window (never for a dedicated server).
+    fn client_started(&self, client: &hooks::Client) {
+        start(client.automated);
+    }
+
+    fn activity(&self, now: Activity) {
+        set(match now {
+            Activity::Menus => Status::Menus,
+            Activity::World {
+                play,
+                dimension,
+                mode,
+            } => Status::World {
+                play,
+                dimension,
+                mode,
+            },
+            // Hidden, and anything a later game says that this crate doesn't know yet.
+            _ => Status::Off,
+        });
+    }
+
+    /// On quit: the activity is cleared.
+    fn shutdown(&self) {
+        stop();
+    }
 }
 
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
@@ -114,7 +132,8 @@ static THREAD: OnceLock<Thread> = OnceLock::new();
 
 /// Starts the presence thread, once: when the game starts, never for a dedicated server.
 /// `automated` runs (offscreen, benchmarks) only talk to a test's fake Discord.
-pub fn start(enabled: bool, automated: bool) {
+/// The status [`set`] gave before, the switch included, is the first one sent.
+pub fn start(automated: bool) {
     let fake_discord = std::env::var_os(IPC_DIR_ENV).is_some();
     if THREAD.get().is_some()
         || std::env::var_os("HORIZON_NO_DISCORD").is_some_and(|v| v != "0")
@@ -122,9 +141,6 @@ pub fn start(enabled: bool, automated: bool) {
     {
         return;
     }
-    if !enabled {
-        lock().wanted.status = Status::Off;
-    }
     match std::thread::Builder::new()
         .name("Discord presence".into())
         .spawn(run)
@@ -136,12 +152,10 @@ pub fn start(enabled: bool, automated: bool) {
     }
 }
 
-/// What the player does now; only a change wakes the thread. Free without [`start`].
+/// What the player does now; only a change wakes the thread. Kept for [`start`] before it.
 pub fn set(status: Status) {
-    let Some(thread) = THREAD.get() else {
-        return;
-    };
-    if lock().wanted.update(status, unix_now()) {
+    let changed = lock().wanted.update(status, unix_now());
+    if let Some(thread) = THREAD.get().filter(|_| changed) {
         thread.unpark();
     }
 }

crates/horizon-hooks/src/lib.rs

@@ -77,12 +77,82 @@ pub trait Hooks: Sync {
     /// Draws on a player model, after its vanilla layers, each time it is drawn.
     fn player_layers(&self, _model: &players::PlayerModel, _draw: &mut dyn players::PlayerDraw) {}
 
+    /// Draws around the window's own model while its body is out of view (first person), once a
+    /// frame after the first-person model: [`players::Pass::FirstPerson`].
+    fn first_person(&self, _own: &players::PlayerModel, _draw: &mut dyn players::PlayerDraw) {}
+
     /// The resolver of `friend:` addresses this crate offers ([`tunnel`]); the first hook that
     /// offers one is used. Asked on the network thread when joining and on the game thread when
     /// an address is shown, never per frame.
     fn tunnel(&self) -> Option<&dyn tunnel::Resolver> {
         None
     }
+
+    /// A game window opened: once, before the first frame, for every run that has a window,
+    /// automated ones included ([`Client::automated`]); never for a dedicated server.
+    fn client_started(&self, _client: &Client) {}
+
+    /// What the player is doing, for a status shown outside the game (Discord's): called when it
+    /// changes, not every frame. Splitscreen: the first player's only.
+    fn activity(&self, _now: Activity) {}
+}
+
+/// What [`Hooks::client_started`] gets.
+#[non_exhaustive]
+pub struct Client {
+    /// A run nobody plays: offscreen, a benchmark, a run that quits by itself after some frames.
+    pub automated: bool,
+}
+
+impl Client {
+    pub fn new(automated: bool) -> Self {
+        Self { automated }
+    }
+}
+
+/// What the player is doing ([`Hooks::activity`]).
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+#[non_exhaustive]
+pub enum Activity {
+    /// The player keeps it to themselves: the Discord switch in Horizon Settings is off. (The
+    /// switch moves to the Discord crate's own settings with the settings store.)
+    Hidden,
+    /// On the title screen or another menu outside a world.
+    Menus,
+    World {
+        play: Play,
+        dimension: Dimension,
+        mode: GameMode,
+    },
+}
+
+/// How the player is in a world.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum Play {
+    Singleplayer,
+    /// A server or someone else's LAN world.
+    Multiplayer,
+    /// Their world is open to LAN or friends; `players` counts the host, `max` is how many may
+    /// join.
+    Hosting {
+        players: usize,
+        max: usize,
+    },
+}
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum Dimension {
+    Overworld,
+    Nether,
+    End,
+}
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum GameMode {
+    Survival,
+    Creative,
+    Adventure,
+    Spectator,
 }
 
 /// What [`Hooks::started`] gets.
@@ -178,6 +248,32 @@ pub mod engine {
         }
     }
 
+    /// [`Hooks::client_started`].
+    pub fn client_started(client: &Client) {
+        for hooks in all() {
+            hooks.client_started(client);
+        }
+    }
+
+    /// The activity at the last call (`None` before the first).
+    static ACTIVITY: std::sync::Mutex<Option<Activity>> = std::sync::Mutex::new(None);
+
+    /// [`Hooks::activity`], when `now` differs from the last call's. Cheap enough to call every
+    /// frame: with no hook registered it only loads the empty list.
+    pub fn activity(now: Activity) {
+        let hooks = all();
+        if hooks.is_empty() {
+            return;
+        }
+        let mut last = ACTIVITY.lock().unwrap_or_else(|e| e.into_inner());
+        if last.replace(now) != Some(now) {
+            drop(last);
+            for h in hooks {
+                h.activity(now);
+            }
+        }
+    }
+
     /// [`Hooks::shutdown`].
     pub fn shutdown() {
         for hooks in all() {
@@ -217,6 +313,13 @@ pub mod engine {
         }
     }
 
+    /// [`Hooks::first_person`].
+    pub fn first_person(own: &players::PlayerModel, draw: &mut dyn players::PlayerDraw) {
+        for hooks in all() {
+            hooks.first_person(own, draw);
+        }
+    }
+
     /// [`Hooks::camera`].
     pub fn camera(own: &players::CameraView) -> Option<players::CameraOverride> {
         all().iter().find_map(|h| h.camera(own))
@@ -255,6 +358,9 @@ mod tests {
         fn published(&self, open: bool) {
             self.0.lock().unwrap().push(format!("published {open}"));
         }
+        fn activity(&self, now: Activity) {
+            self.0.lock().unwrap().push(format!("{now:?}"));
+        }
         fn frame(&self, frame: &players::Frame, sprites: &mut dyn players::SpriteStore) {
             self.0
                 .lock()
@@ -285,7 +391,14 @@ mod tests {
                 return;
             };
             let turn = draw.ticks() / 100.0;
-            draw.draw(&HAT, head, uv, &mut |p| p.pose("brim")[4] = turn);
+            let look = players::Look::new(uv);
+            draw.draw(&HAT, head, look, &mut |p| p.pose("brim")[4] = turn);
+        }
+        /// A spark at the eyes, as bright as the head turns.
+        fn first_person(&self, _: &players::PlayerModel, draw: &mut dyn players::PlayerDraw) {
+            let alpha = draw.motion().head_yaw / 90.0;
+            let spark = players::Particle::new([[0.0; 3]; 4], [[0.0; 2]; 4], alpha);
+            draw.particles([0.0; 4], &[spark], players::Light::Full);
         }
         fn tick(&self, models: &mut dyn players::PlayerModels) {
             let mut ids = Vec::new();
@@ -362,9 +475,10 @@ mod tests {
             ))
         });
 
-    /// A player drawn at age 50, its head where the camera is; logs each draw.
+    /// A player drawn at age 50, its head where the camera is, turned 45 degrees; logs each draw
+    /// and its particles' alphas.
     #[derive(Default)]
-    struct Canvas(Vec<(String, [[f32; 4]; 4], [f32; 4], f32)>);
+    struct Canvas(Vec<(String, [[f32; 4]; 4], [f32; 4], f32)>, Vec<f32>);
     impl players::PlayerDraw for Canvas {
         fn pass(&self) -> players::Pass {
             players::Pass::World
@@ -372,6 +486,15 @@ mod tests {
         fn ticks(&self) -> f32 {
             50.0
         }
+        fn base(&self) -> [[f32; 4]; 4] {
+            [[1.0, 0.0, 0.0, 0.0]; 4]
+        }
+        fn motion(&self) -> players::Motion {
+            players::Motion::new([0.0; 3], 45.0, 0.0)
+        }
+        fn view(&self) -> players::View {
+            players::View::default()
+        }
         fn bone(&mut self, bone: players::Bone) -> Option<[[f32; 4]; 4]> {
             (bone == players::Bone::Head).then_some([[1.0, 0.0, 0.0, 0.0]; 4])
         }
@@ -385,7 +508,7 @@ mod tests {
             &mut self,
             mesh: &std::sync::Arc<players::Mesh>,
             matrix: [[f32; 4]; 4],
-            uv: [f32; 4],
+            look: players::Look,
             pose: &mut dyn FnMut(&mut dyn players::PartPoses),
         ) {
             struct Rest([f32; 9]);
@@ -396,7 +519,10 @@ mod tests {
             }
             let mut brim = Rest(mesh.children[0].pose);
             pose(&mut brim);
-            self.0.push((mesh.name.clone(), matrix, uv, brim.0[4]));
+            self.0.push((mesh.name.clone(), matrix, look.uv, brim.0[4]));
+        }
+        fn particles(&mut self, _: [f32; 4], particles: &[players::Particle], _: players::Light) {
+            self.1.extend(particles.iter().map(|p| p.alpha));
         }
     }
 
@@ -415,6 +541,14 @@ mod tests {
         for open in [false, true, true, true, false, false] {
             engine::published(open);
         }
+        for now in [
+            Activity::Menus,
+            Activity::Menus,
+            Activity::Hidden,
+            Activity::Hidden,
+        ] {
+            engine::activity(now);
+        }
         engine::shutdown();
         assert!(engine::any());
         let mut atlas = Atlas::default();
@@ -445,6 +579,8 @@ mod tests {
                 0.5
             )]
         );
+        engine::first_person(&model(players::Kind::Own), &mut canvas);
+        assert_eq!(canvas.1, [0.5]);
         let mut models = Two(Default::default());
         engine::tick(&mut models);
         assert!(models.body_pose(3).is_some() && models.body_pose(7).is_some());
@@ -454,6 +590,8 @@ mod tests {
                 "started 0.2.31",
                 "published true",
                 "published false",
+                "Menus",
+                "Hidden",
                 "frame 4"
             ]
         );

crates/horizon-hooks/src/pages.rs

@@ -19,11 +19,6 @@ pub enum Place {
     /// start a group of their own after the page's. A [`Row::Heading`] starts another group. A
     /// [`Row::Key`] shows its key there, without changing it: give a page of its own to a key.
     Extras,
-    /// The title screen's Friends icon slot (vanilla's `CommonButtons.friends`, beside Language
-    /// and Accessibility): with a page registered here the icon opens the first one as a form of
-    /// its own, as Join a Friend is drawn ([`Row::Field`]). It shows heading, note, text, space,
-    /// field and button rows; the others belong in the options shell.
-    Title,
 }
 
 /// One page. Its values live in the crate (statics, often its settings [`crate::settings::Store`]);
@@ -45,11 +40,6 @@ pub trait Page: Sync {
     fn tooltip(&self, _row: usize) -> Option<Label> {
         None
     }
-    /// The label of the button the engine adds to leave a page drawn as its own screen: a
-    /// translation key, `gui.done` by default (`gui.cancel` for a form that does something).
-    fn back(&self) -> &'static str {
-        "gui.done"
-    }
 }
 
 /// A row of a page. Labels are translation keys.
@@ -95,16 +85,6 @@ pub enum Row {
     /// A key binding, as Key Binds shows one: `key` is its key name (`key.keyboard.z`,
     /// `key.mouse.left`). A press waits for the next key or mouse button ([`Act::Bind`]).
     Key { label: &'static str, key: String },
-    /// A text field ([`Row::field`]) on a page drawn as its own screen, as vanilla's `EditBox`:
-    /// its label above it, focus by click or Tab, typing, the caret keys, selection, copy and
-    /// paste, at most `max` characters. `text` is its value when the page opens; the engine then
-    /// keeps it, and sends each change ([`Act::Edit`]) and Enter ([`Act::Submit`]).
-    #[non_exhaustive]
-    Field {
-        label: &'static str,
-        text: String,
-        max: usize,
-    },
 }
 
 impl Row {
@@ -127,23 +107,6 @@ impl Row {
         }
     }
 
-    /// A text field starting with `text`, at most 32 characters (`EditBox`'s default).
-    pub fn field(label: &'static str, text: impl Into<String>) -> Self {
-        Self::Field {
-            label,
-            text: text.into(),
-            max: 32,
-        }
-    }
-
-    /// A text field taking at most `chars` characters.
-    pub fn max(mut self, chars: usize) -> Self {
-        if let Self::Field { max, .. } = &mut self {
-            *max = chars;
-        }
-        self
-    }
-
     /// A button greyed out (`false`): drawn, never pressed.
     pub fn active(mut self, on: bool) -> Self {
         if let Self::Button { active, .. } = &mut self {
@@ -204,19 +167,6 @@ pub enum Act {
     Slide(f32),
     /// A key row got its new key: its key name (`key.keyboard.z`).
     Bind(String),
-    /// A field's text changed: all of it.
-    Edit(String),
-    /// Enter in a field.
-    Submit,
-}
-
-/// The server a page asked to join ([`connect`]).
-static CONNECT: std::sync::Mutex<Option<String>> = std::sync::Mutex::new(None);
-
-/// From a [`Place::Title`] page's [`Page::act`]: join the server at `address` as Direct
-/// Connection does (the engine's addresses, `friend:<code>` among them), once the act returns.
-pub fn connect(address: impl Into<String>) {
-    *CONNECT.lock().unwrap_or_else(|e| e.into_inner()) = Some(address.into());
 }
 
 static PAGES: Registry<dyn Page> = Registry::new();
@@ -235,9 +185,4 @@ pub mod engine {
     pub fn all() -> &'static [&'static dyn Page] {
         PAGES.all()
     }
-
-    /// The server a page asked to join since the last call ([`connect`]).
-    pub fn take_connect() -> Option<String> {
-        CONNECT.lock().unwrap_or_else(|e| e.into_inner()).take()
-    }
 }

crates/horizon-hooks/src/players.rs

@@ -274,8 +274,149 @@ impl Bone {
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 #[non_exhaustive]
 pub enum Pass {
-    /// In the world, seen by the camera.
+    /// In the world, seen by the camera (the window's own model too, in third person).
     World,
+    /// The inventory's picture of the window's own model.
+    Picture,
+    /// The window's own model while its body is out of view (first person): no bone, only what
+    /// floats around it ([`crate::Hooks::first_person`]).
+    FirstPerson,
+}
+
+/// How a player model moves this frame ([`PlayerDraw::motion`]), with the frame's part of a tick.
+#[derive(Clone, Copy, Debug, Default)]
+#[non_exhaustive]
+pub struct Motion {
+    /// Where its feet are, in the world.
+    pub feet: [f64; 3],
+    /// Where its head turns (degrees, the game's yaw and pitch).
+    pub head_yaw: f32,
+    pub head_pitch: f32,
+    pub crouching: bool,
+    /// Lies in a bed.
+    pub asleep: bool,
+    /// Flies with an elytra.
+    pub flying: bool,
+    /// Swims (any part of the swimming pose).
+    pub swimming: bool,
+}
+
+impl Motion {
+    pub fn new(feet: [f64; 3], head_yaw: f32, head_pitch: f32) -> Self {
+        Self {
+            feet,
+            head_yaw,
+            head_pitch,
+            ..Self::default()
+        }
+    }
+
+    /// With its poses: crouching, asleep, flying, swimming.
+    pub fn poses(self, crouching: bool, asleep: bool, flying: bool, swimming: bool) -> Self {
+        Self {
+            crouching,
+            asleep,
+            flying,
+            swimming,
+            ..self
+        }
+    }
+}
+
+/// The camera a player model is drawn for ([`PlayerDraw::view`]).
+#[derive(Clone, Copy, Debug, Default)]
+#[non_exhaustive]
+pub struct View {
+    /// Where it is, in the world: matrices and [`Particle`] corners are relative to it.
+    pub camera: [f64; 3],
+    /// Its right and up, for what faces it.
+    pub right: [f32; 3],
+    pub up: [f32; 3],
+    /// Where the window's player looks, and their level left (first person).
+    pub forward: [f32; 3],
+    pub left: [f32; 3],
+}
+
+impl View {
+    pub fn new(camera: [f64; 3], right: [f32; 3], up: [f32; 3]) -> Self {
+        Self {
+            camera,
+            right,
+            up,
+            ..Self::default()
+        }
+    }
+
+    /// With where the window's player looks and their level left.
+    pub fn looking(self, forward: [f32; 3], left: [f32; 3]) -> Self {
+        Self {
+            forward,
+            left,
+            ..self
+        }
+    }
+}
+
+/// How a mesh or particles are lit.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+#[non_exhaustive]
+pub enum Light {
+    /// As the player model is.
+    Model,
+    /// Fully lit: it glows.
+    Full,
+    /// By the world where the mesh's origin is (as particles: like [`Light::Model`]).
+    AtPlace,
+}
+
+/// How [`PlayerDraw::draw`] draws a mesh.
+#[derive(Clone, Copy, Debug)]
+#[non_exhaustive]
+pub struct Look {
+    /// The sprite part it is textured by (u0, v0, u1, v1).
+    pub uv: [f32; 4],
+    pub light: Light,
+    /// Drawn see-through at this alpha, after every player, its back faces dropped.
+    pub see_through: Option<f32>,
+}
+
+impl Look {
+    /// Opaque, lit as the model.
+    pub fn new(uv: [f32; 4]) -> Self {
+        Self {
+            uv,
+            light: Light::Model,
+            see_through: None,
+        }
+    }
+
+    pub fn lit(self, light: Light) -> Self {
+        Self { light, ..self }
+    }
+
+    pub fn see_through(self, alpha: f32) -> Self {
+        Self {
+            see_through: Some(alpha),
+            ..self
+        }
+    }
+}
+
+/// A quad that faces the camera ([`PlayerDraw::particles`]).
+#[derive(Clone, Copy, Debug)]
+#[non_exhaustive]
+pub struct Particle {
+    /// Its corners, relative to the camera.
+    pub corners: [[f32; 3]; 4],
+    /// Each corner's place across the sprite part (0 to 1).
+    pub uv: [[f32; 2]; 4],
+    pub alpha: f32,
+}
+
+impl Particle {
+    pub fn new(corners: [[f32; 3]; 4], uv: [[f32; 2]; 4], alpha: f32) -> Self {
+        Self { corners, uv, alpha }
+    }
 }
 
 /// The poses of a [`Mesh`]'s parts for one [`PlayerDraw::draw`], each at rest to begin with.
@@ -291,19 +432,25 @@ pub trait PlayerDraw {
     fn pass(&self) -> Pass;
     /// The model's age in ticks, with the frame's part of a tick.
     fn ticks(&self) -> f32;
-    /// Where `bone` is as the body is drawn this frame; None if the model has no such part.
+    /// The model's own matrix, its origin at the neck (y down, 16 units a block).
+    fn base(&self) -> [[f32; 4]; 4];
+    fn motion(&self) -> Motion;
+    fn view(&self) -> View;
+    /// Where `bone` is as the body is drawn this frame; None if the model has no such part (or
+    /// no body is drawn: [`Pass::FirstPerson`]).
     fn bone(&mut self, bone: Bone) -> Option<[[f32; 4]; 4]>;
     /// The pose laid over the model's body ([`PlayerModels::set_body_pose`]), if any.
     fn body_pose(&self) -> Option<&Arc<dyn BodyPose>>;
     /// As [`Sprites::get`].
     fn sprite(&self, id: u64) -> Option<[f32; 4]>;
-    /// Draws `mesh` at `matrix`, textured by the sprite part `uv` (u0, v0, u1, v1) and lit as the
-    /// model is; `pose` poses its parts first.
+    /// Draws `mesh` at `matrix` as `look` says; `pose` poses its parts first.
     fn draw(
         &mut self,
         mesh: &Arc<Mesh>,
         matrix: [[f32; 4]; 4],
-        uv: [f32; 4],
+        look: Look,
         pose: &mut dyn FnMut(&mut dyn PartPoses),
     );
+    /// Draws `particles`, textured by the sprite part `uv`, see-through after every player.
+    fn particles(&mut self, uv: [f32; 4], particles: &[Particle], light: Light);
 }

crates/horizon-official/Cargo.toml

@@ -16,6 +16,7 @@ horizon-platform = { path = "../horizon-platform" }
 horizon-heartbeat = { path = "../horizon-heartbeat" }
 horizon-friends = { path = "../horizon-friends", features = ["game"] }
 horizon-official-servers = { path = "../horizon-official-servers" }
+horizon-discord = { path = "../horizon-discord" }
 log = "0.4"
 
 [build-dependencies]

crates/horizon-official/src/lib.rs

@@ -11,13 +11,15 @@
 use horizon_platform::hooks::{self, Hooks};
 
 /// Every Horizon part in the game, in the order its hooks run.
-const PARTS: [&dyn Hooks; 3] = [
+const PARTS: [&dyn Hooks; 4] = [
     // The anonymous "I'm playing" ping.
     &horizon_heartbeat::HOOKS,
     // Play with Friends: `friend:` addresses join through its tunnel.
     &horizon_friends::game::HOOKS,
     // The official server in the player's server list.
     &horizon_official_servers::HOOKS,
+    // "Playing Horizon" on the player's Discord profile.
+    &horizon_discord::HOOKS,
 ];
 
 /// Registers Horizon's in-game parts with the game. The executable calls it before it runs the

crates/horizon-optifine/src/blink.rs

@@ -81,6 +81,11 @@ impl Blinks {
         self.blinks.is_empty()
     }
 
+    /// The blinks by texture, and [`Self::files`].
+    pub fn into_parts(self) -> (HashMap<String, Blink>, Vec<(String, String)>) {
+        (self.blinks, self.files)
+    }
+
     pub fn get(&self, texture: &str) -> Option<&Blink> {
         self.blinks.get(texture)
     }