Merge branch 'split/cosmetics-sprites' into split/cosmetics-names

Co-Authored-By: Claude Opus 5.5 <[email protected]>

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

@@ -20,14 +20,17 @@ use horizon_cosmetics::follow::Follow;
 use horizon_cosmetics::prefs::{self, Others};
 use horizon_cosmetics::trail::{Budget, Emitter};
 use horizon_cosmetics::{Item, Slot};
-use horizon_hooks::players::{Frame, Kind, PlayerModel, PlayerModels};
+use horizon_hooks::players::{
+    Badge, CameraOverride, CameraView, Frame, Gear, Kind, Mark, NameDecoration, PlayerModel,
+    PlayerModels, SpriteStore, Sprites,
+};
 use std::cell::{Cell, RefCell};
 use std::sync::mpsc::{Receiver, channel};
 use std::sync::{Arc, Mutex, PoisonError};
 use std::time::{Duration, Instant};
 
 /// Horizon's mark before a Horizon player's name, over their name tag and in the player list.
-pub(super) const MARK: horizon_client::tab_list::NameMark = &horizon_cosmetics::mark::MARK;
+const MARK: Mark = &horizon_cosmetics::mark::MARK;
 
 /// An item as the renderer takes it.
 struct Baked {
@@ -397,17 +400,13 @@ fn slot_image(item: &Item) -> Vec<u8> {
 
 /// Which slots an avatar's gear covers: a helmet or head item hides a hat, an elytra or a cape
 /// what is worn on the back. A name tag style is never drawn on the body.
-fn covered(m: &Mob, slot: Slot) -> bool {
+fn covered(gear: Gear, slot: Slot) -> bool {
     match slot {
-        Slot::Head => m.extra.head.is_some(),
-        Slot::Back => m.cape.is_some() || m.extra.chest.as_deref() == Some("minecraft:elytra"),
+        Slot::Head => gear.head,
+        Slot::Back => gear.back,
         Slot::Shoulder => false,
         // A chestplate, not an elytra.
-        Slot::Torso => m
-            .extra
-            .chest
-            .as_deref()
-            .is_some_and(|c| c != "minecraft:elytra"),
+        Slot::Torso => gear.chest,
         Slot::NameTag | Slot::Emote => true,
         // On no bone: drawn by a pass of their own, never on the body.
         Slot::Companion | Slot::Trail | Slot::Aura => true,
@@ -419,12 +418,12 @@ fn covered(m: &Mob, slot: Slot) -> bool {
 /// (`worn` is None), another player's at "name tags only" or hidden, or every item `covered` (a
 /// helmet over a hat). One max over at most five items, read when the item was parsed.
 fn body_top(
-    extras: &horizon_client::extras::Extras,
+    others: Others,
     own: bool,
     worn: Option<&horizon_cosmetics::Worn>,
     covered: impl Fn(Slot) -> bool,
 ) -> Option<f32> {
-    if !own && extras.effective_others() != Others::Shown {
+    if !own && others != Others::Shown {
         return None;
     }
     worn?
@@ -462,6 +461,14 @@ struct Seat {
     said: Said,
     /// Kept between ticks so a tick allocates nothing: the player models in view.
     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>)>,
+    last_sprite: u64,
+    /// Sprites drawing missed, put in the atlas next frame.
+    wanted: Vec<u64>,
 }
 
 /// What the game tells the hooks before each call, until the settings move here (spec #14091
@@ -472,6 +479,14 @@ struct Said {
     listed: bool,
     /// Other players' cosmetics are shown (not "name tags only", not hidden).
     others_shown: bool,
+    /// Other players' cosmetics are hidden (not even name tag styles).
+    others_hidden: bool,
+    /// Horizon's mark by Horizon players' names.
+    marks: bool,
+    /// Cosmetics in single player: the signed-in account's on the player's own model.
+    solo: bool,
+    /// My emote pulled the camera back: when it started (the own model's age).
+    pull: Option<f32>,
     /// My emote while it plays: its id and whether it loops.
     playing: Option<(String, bool)>,
     /// A folder's first emote, which mannequins play.
@@ -496,13 +511,39 @@ pub(super) struct Hooks;
 pub(super) static HOOKS: Hooks = Hooks;
 
 impl horizon_hooks::Hooks for Hooks {
-    fn frame(&self, _frame: &Frame) {
-        service(Seat::frame);
+    fn frame(&self, frame: &Frame, sprites: &mut dyn SpriteStore) {
+        service(|s| {
+            s.solo = frame.solo;
+            s.frame();
+            s.put_sprites(sprites);
+        });
     }
 
     fn tick(&self, models: &mut dyn PlayerModels) {
         service(|s| s.tick(models));
     }
+
+    fn name_decoration(
+        &self,
+        model: &PlayerModel,
+        sprites: &dyn Sprites,
+    ) -> Option<NameDecoration> {
+        service(|s| s.name_decoration(model, sprites))
+    }
+
+    fn player_mark(&self, uuid: u128) -> Option<Mark> {
+        service(|s| {
+            let client = s.client.as_ref().filter(|_| s.said.marks)?;
+            client.frame().horizon(uuid).then_some(MARK)
+        })
+    }
+
+    /// An emote pulls the camera back: it eases out over the emote's first quarter second.
+    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);
+        Some(CameraOverride::new(0.35 + 0.65 * t * t * (3.0 - 2.0 * t)))
+    }
 }
 
 impl Seat {
@@ -609,6 +650,81 @@ impl Seat {
         }
     }
 
+    /// What goes by `m`'s name: Horizon's mark if they play Horizon (and the mark is on), the
+    /// name tag style they wear if cosmetics are shown for them (name tags only counts), and how
+    /// high what is drawn on their body gets (`body_top`). One look in the cache for all three.
+    fn name_decoration(
+        &mut self,
+        m: &PlayerModel,
+        sprites: &dyn Sprites,
+    ) -> Option<NameDecoration> {
+        let said = &self.said;
+        let own = m.kind == Kind::Own;
+        let styles = if own { said.mine } else { !said.others_hidden };
+        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 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 };
+        drop(frame);
+        let others = if said.others_shown {
+            Others::Shown
+        } else {
+            Others::NameTags
+        };
+        let top = body_top(others, own, worn.as_ref(), |slot| covered(m.gear, slot))
+            .filter(|_| !m.invisible);
+        let badge = worn.and_then(|w| self.badge(&w, sprites));
+        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;
+        let next = self.last_sprite + 1;
+        let (id, _) = *self
+            .sprites
+            .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 {
+            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]),
+        ))
+    }
+
+    /// Puts the sprites drawing missed in the atlas; forgets those of 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));
+            }
+        }
+        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
     /// they play on their models; one that moved ends theirs here at once. Others' emotes show
     /// with "Other players' cosmetics" on Shown only; otherwise nothing is asked.
@@ -705,11 +821,16 @@ impl Game<'_> {
         };
         let extras = &self.settings.extras;
         let playing = self.cosmetics.emotes.sending();
+        let pull = self.cosmetics.emotes.pull();
         service(|s| {
             let said = &mut s.said;
             said.mine = extras.cosmetics_mine;
             said.listed = extras.horizon_listed;
             said.others_shown = extras.effective_others() == Others::Shown;
+            said.others_hidden = extras.effective_others() == Others::Hidden;
+            said.marks = extras.horizon_marks;
+            said.solo = extras.cosmetics_solo;
+            said.pull = pull;
             if said.playing.as_ref().map(|(id, l)| (id.as_str(), *l)) != playing {
                 said.playing = playing.map(|(id, l)| (id.to_owned(), l));
             }
@@ -775,81 +896,6 @@ impl Game<'_> {
             .ok();
     }
 
-    /// Items from a folder (`HORIZON_COSMETICS_LOCAL`): mannequins are dressed and marked too.
-    pub(super) fn cosmetics_local(&self) -> bool {
-        self.cosmetics.local
-    }
-
-    /// What goes by `m`'s name: Horizon's mark if they play Horizon (and the mark is on), the
-    /// name tag style they wear if cosmetics are shown for them (name tags only counts), and how
-    /// high what is drawn on their body gets (`body_top`). One look in the cache for all three.
-    pub(super) fn cosmetics_marks(&self, m: &Mob, own: bool) -> super::names::Marks {
-        let mut marks = super::names::Marks::default();
-        let extras = &self.settings.extras;
-        let styles = if own {
-            extras.cosmetics_mine
-        } else {
-            extras.effective_others() != Others::Hidden
-        };
-        if !(styles || extras.horizon_marks) {
-            return marks;
-        }
-        let (Some(client), Some(uuid)) = (&self.cosmetics.client, self.cosmetics_uuid(m, own))
-        else {
-            return marks;
-        };
-        let mut frame = client.frame();
-        marks.horizon = extras.horizon_marks && frame.horizon(uuid);
-        let worn = if styles { frame.worn(uuid) } else { None };
-        drop(frame);
-        if !horizon_client::mobs::trader::is_invisible(m) {
-            marks.top = body_top(extras, own, worn.as_ref(), |slot| covered(m, slot));
-        }
-        marks.style = worn.and_then(|w| self.cosmetics_tag(&w));
-        marks
-    }
-
-    /// Those of `uuids` who play Horizon, with the mark on (the player list): one look each.
-    pub(super) fn horizon_players(
-        &self,
-        uuids: impl Iterator<Item = u128>,
-    ) -> std::collections::HashSet<u128> {
-        match &self.cosmetics.client {
-            Some(c) if self.settings.extras.horizon_marks => {
-                let mut frame = c.frame();
-                uuids.filter(|u| frame.horizon(*u)).collect()
-            }
-            _ => Default::default(),
-        }
-    }
-
-    /// 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.
-    fn cosmetics_tag(&self, worn: &horizon_cosmetics::Worn) -> Option<super::names::TagStyle> {
-        let item = worn.iter().find(|i| i.slot == Slot::NameTag)?;
-        let [r, g, b] = item.tag?.line;
-        let frame = self.cosmetics.frame.get();
-        let mut baked = self.cosmetics.baked.borrow_mut();
-        let entry = baked
-            .entry(Arc::as_ptr(item) as usize)
-            .or_insert_with(|| Baked::new(item, frame));
-        let Some(slot) = self.gui.atlas.sprites.get(&entry.location) else {
-            self.cosmetics.uploads.borrow_mut().push(item.clone());
-            return None;
-        };
-        if entry.marked.replace(frame) != frame {
-            self.skin_downloads.borrow_mut().drawn(&entry.location);
-        }
-        // The mark sits in the slot's top left corner.
-        let mut mark = *slot;
-        mark.u1 = mark.u0 + (slot.u1 - slot.u0) * item.texture.width as f32 / 64.0;
-        mark.v1 = mark.v0 + (slot.v1 - slot.v0) * item.texture.height as f32 / 64.0;
-        Some(super::names::TagStyle {
-            mark,
-            line: u32::from_be_bytes([0, r, g, b]),
-        })
-    }
-
     /// What `m` wears, if cosmetics are shown for it: `own` for the player's own model.
     fn worn(&self, m: &Mob, own: bool) -> Option<horizon_cosmetics::Worn> {
         let client = self.cosmetics.client.as_ref()?;
@@ -941,7 +987,7 @@ impl Game<'_> {
                 }
                 continue;
             }
-            if emoting.is_none() && covered(m, item.slot) {
+            if emoting.is_none() && covered(super::player_hooks::gear(m), item.slot) {
                 continue;
             }
             let Some((models, uv)) = self.cosmetics_baked(item) else {
@@ -1247,13 +1293,18 @@ mod tests {
         let (short, long) = (Duration::from_millis(300), Duration::from_secs(10));
         let top_of = |extras: &Extras, patience| {
             let (worn, _) = other_player_from(Service(Arc::default(), both), extras, patience);
-            body_top(extras, false, worn.as_ref(), |_| false)
+            body_top(extras.effective_others(), false, worn.as_ref(), |_| false)
         };
         // No cosmetics drawn on the body (a name tag style only): vanilla's height exactly.
         let (worn, _) = other_player(&shown, long);
         assert!(worn.is_some());
         assert_eq!(
-            tag(body_top(&shown, false, worn.as_ref(), |_| false)),
+            tag(body_top(
+                shown.effective_others(),
+                false,
+                worn.as_ref(),
+                |_| false
+            )),
             VANILLA
         );
         // A small hat under the tag: vanilla's height too.
@@ -1267,7 +1318,9 @@ mod tests {
         );
         // A helmet over it: vanilla's height.
         let (worn, _) = other_player_from(Service(Arc::default(), both), &shown, long);
-        let helmet = body_top(&shown, false, worn.as_ref(), |slot| slot == Slot::Head);
+        let helmet = body_top(shown.effective_others(), false, worn.as_ref(), |slot| {
+            slot == Slot::Head
+        });
         assert_eq!(tag(helmet), VANILLA);
         // Others' cosmetics on name tags only, or hidden: nothing on the body, vanilla's height.
         for others in [Others::NameTags, Others::Hidden] {

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

@@ -43,6 +43,11 @@ impl Emotes {
         let looping = p.item.emote.as_ref().is_some_and(|e| e.looping);
         Some((&p.item.id, looping))
     }
+
+    /// When the emote that pulled the camera back started (the own model's age), while it plays.
+    pub(in crate::game) fn pull(&self) -> Option<f32> {
+        self.camera_from.and(self.playing.as_ref()).map(|p| p.start)
+    }
 }
 
 /// An emote on a player's model: the engine's pose hook (`Mob::emote`), which names no cosmetics
@@ -277,19 +282,6 @@ impl Game<'_> {
         }
         self.tick_emote();
     }
-
-    /// How far the camera stands back while an emote pulls it (1: the usual distance): it eases
-    /// out over the emote's first quarter second.
-    pub(in crate::game) fn emote_camera_pull(&self, partial: f32) -> f32 {
-        let (Some(p), Some(m)) = (&self.cosmetics.emotes.playing, &self.player_model) else {
-            return 1.0;
-        };
-        if self.cosmetics.emotes.camera_from.is_none() {
-            return 1.0;
-        }
-        let t = ((m.age as f32 + partial - p.start) / 5.0).clamp(0.0, 1.0);
-        0.35 + 0.65 * t * t * (3.0 - 2.0 * t)
-    }
 }
 
 #[cfg(test)]

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

@@ -300,11 +300,7 @@ impl Game<'_> {
             ) {
                 continue;
             }
-            let marks = if player || self.cosmetics_local() {
-                self.cosmetics_marks(m, Some(m.id) == own)
-            } else {
-                Marks::default()
-            };
+            let marks = self.hooks_name_marks(m, Some(m.id) == own);
             let at = match marks.top {
                 Some(top) => p + glam::DVec3::Y * cosmetic_lift(top, m.model_scale()),
                 None => p,
@@ -770,10 +766,10 @@ impl Game<'_> {
                     if background { BACKGROUND } else { 0 },
                 ),
             };
-            if n == last && marks.horizon {
+            if let Some(mark) = marks.mark.filter(|_| n == last) {
                 let x = -self.gui.atlas.font.width_text(text) / 2.0 - 10.0;
                 // 8 text pixels square, a pixel left of the background.
-                for &(mx, my, w, h, argb) in super::cosmetics::MARK {
+                for &(mx, my, w, h, argb) in mark {
                     let a = text_alpha * (argb >> 24) / 255;
                     batch.fill(
                         &self.gui.atlas,
@@ -937,10 +933,11 @@ struct NameTag {
     marks: Marks,
 }
 
-/// What Horizon draws by a player's name: its mark (they play Horizon) and their name tag style.
+/// What a hook draws by a player's name (`horizon_hooks::players::NameDecoration`): a mark
+/// before it (Horizon's: they play Horizon) and a name tag style.
 #[derive(Clone, Copy, Default)]
 pub(super) struct Marks {
-    pub horizon: bool,
+    pub mark: Option<horizon_hooks::players::Mark>,
     pub style: Option<TagStyle>,
     /// How high the cosmetics drawn on their body get above the neck, in model pixels: the tag
     /// goes up over a tall one (`cosmetic_lift`).

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

@@ -311,8 +311,8 @@ impl Game<'_> {
             }
         };
         let mut view = self.view;
-        // An emote pulls the camera back from the player's face (`game/cosmetics/emotes.rs`).
-        let pull = self.emote_camera_pull(partial);
+        // A hook may pull the camera back (an emote, from the player's face).
+        let pull = self.hooks_camera_distance(partial);
         let kind = match self.camera_type {
             CameraType::FirstPerson => horizon_client::camera::CameraType::FirstPerson,
             CameraType::ThirdPersonBack => horizon_client::camera::CameraType::ThirdPersonBack,

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

@@ -1,14 +1,16 @@
-//! Where the game hands the player models to crates above the engine
-//! (`horizon_hooks::Hooks::frame` and `tick`, spec #14091): only a window's game calls them,
-//! never the integrated server's thread or a dedicated server. With no hook registered nothing is
-//! built.
+//! Where the game hands the player models to crates above the engine (`horizon_hooks::Hooks`'s
+//! `frame`, `tick`, `name_decoration`, `player_mark`, `camera`; spec #14091): only a window's
+//! game calls them, never the integrated server's thread or a dedicated server. With no hook
+//! registered nothing is built.
 
 use super::Game;
 use horizon_client::join_seq::JoinList;
 use horizon_client::mobs::Mob;
 use horizon_client::mobs::anim::BodyPose;
 use horizon_hooks::engine;
-use horizon_hooks::players::{Frame, Kind, PlayerModel, PlayerModels};
+use horizon_hooks::players::{
+    CameraView, Frame, Gear, Kind, PlayerModel, PlayerModels, SpriteStore, Sprites,
+};
 use std::sync::Arc;
 
 /// Registers the hooks of the Horizon parts still in this crate (cosmetics: spec #14091 step 5
@@ -49,9 +51,20 @@ fn kind(m: &Mob) -> Option<Kind> {
     }
 }
 
+/// What `m` wears where a crate may draw: a helmet or head item, a chestplate, a cape or elytra.
+pub(super) fn gear(m: &Mob) -> Gear {
+    let elytra = m.extra.chest.as_deref() == Some("minecraft:elytra");
+    Gear::new(
+        m.extra.head.is_some(),
+        m.extra.chest.is_some() && !elytra,
+        m.cape.is_some() || elytra,
+    )
+}
+
 fn model(m: &Mob, kind: Kind, uuid: Option<u128>) -> PlayerModel {
     let (dx, dz) = (m.position.x - m.previous.x, m.position.z - m.previous.z);
     PlayerModel::new(m.id, kind, uuid, m.age, dx * dx + dz * dz > 1e-4)
+        .looks(gear(m), horizon_client::mobs::trader::is_invisible(m))
 }
 
 impl PlayerModels for Models<'_> {
@@ -61,7 +74,7 @@ impl PlayerModels for Models<'_> {
 
     fn for_each(&self, f: &mut dyn FnMut(PlayerModel)) {
         if let Some(m) = self.own.as_deref() {
-            f(model(m, Kind::Own, None));
+            f(model(m, Kind::Own, Some(self.remote.profile())));
         }
         for m in self.mobs.iter() {
             if let Some(kind) = kind(m) {
@@ -92,6 +105,47 @@ impl PlayerModels for Models<'_> {
     }
 }
 
+/// Sprite `id`'s place in the atlas's names (`hooks/<hex>`), written into `buf`: no allocation.
+fn location(id: u64, buf: &mut [u8; 22]) -> &str {
+    use std::io::Write;
+    let mut out = std::io::Cursor::new(&mut buf[..]);
+    let _ = write!(out, "hooks/{id:x}");
+    let len = out.position() as usize;
+    std::str::from_utf8(&buf[..len]).unwrap_or_default()
+}
+
+/// The crates' sprites in the GUI atlas, in the skin slots: read while drawing.
+struct HookSprites<'a, 'g>(&'a Game<'g>);
+
+impl Sprites for HookSprites<'_, '_> {
+    fn get(&self, id: u64) -> Option<[f32; 4]> {
+        let mut buf = [0; 22];
+        let at = location(id, &mut buf);
+        let r = self.0.gui.atlas.sprites.get(at)?;
+        // Kept this frame (`skin_slots.next_frame`).
+        self.0.skin_downloads.borrow_mut().drawn(at);
+        Some([r.u0, r.v0, r.u1, r.v1])
+    }
+}
+
+/// Where a crate's frame hook puts its sprites.
+struct HookStore<'a, 'g>(&'a mut Game<'g>);
+
+impl SpriteStore for HookStore<'_, '_> {
+    fn has(&self, id: u64) -> bool {
+        self.0
+            .gui
+            .atlas
+            .sprites
+            .contains_key(location(id, &mut [0; 22]))
+    }
+
+    fn put(&mut self, id: u64, rgba: Vec<u8>) {
+        let at = location(id, &mut [0; 22]).to_owned();
+        self.0.store_skin(at, rgba);
+    }
+}
+
 impl Game<'_> {
     /// Once a frame, before drawing.
     pub(super) fn client_hooks_frame(&mut self) {
@@ -104,7 +158,8 @@ impl Game<'_> {
         }
         self.cosmetics_say();
         let connection = self.remote.as_ref().map_or(0, |r| r.session.serial());
-        engine::frame(&Frame::new(connection));
+        let frame = Frame::new(connection, self.integrated.is_some());
+        engine::frame(&frame, &mut HookStore(self));
         self.cosmetics_frame();
     }
 
@@ -128,4 +183,68 @@ impl Game<'_> {
             remote,
         });
     }
+
+    /// What goes by `m`'s name (`own`: the window's own player), from the hooks.
+    pub(super) fn hooks_name_marks(&self, m: &Mob, own: bool) -> super::names::Marks {
+        debug_assert!(
+            self.serving.is_none(),
+            "a server thread calls no client hook"
+        );
+        let mut marks = super::names::Marks::default();
+        if !engine::any() {
+            return marks;
+        }
+        let model = match (own, kind(m)) {
+            (true, _) => model(m, Kind::Own, self.remote.as_ref().map(|r| r.profile())),
+            (false, Some(kind)) => model(m, kind, self.remote_player_uuid(m.id)),
+            (false, None) => return marks,
+        };
+        if let Some(d) = engine::name_decoration(&model, &HookSprites(self)) {
+            marks.mark = d.mark;
+            marks.top = d.top;
+            marks.style = d.badge.map(|b| {
+                let [u0, v0, u1, v1] = b.uv;
+                super::names::TagStyle {
+                    mark: horizon_client::hud::Rect {
+                        u0,
+                        v0,
+                        u1,
+                        v1,
+                        w: 8,
+                        h: 8,
+                    },
+                    line: b.line,
+                }
+            });
+        }
+        marks
+    }
+
+    /// How far the third-person camera stands back, as a share of the usual distance: a hook's
+    /// (an emote pulls it back), else 1.
+    pub(super) fn hooks_camera_distance(&self, partial: f32) -> f32 {
+        debug_assert!(
+            self.serving.is_none(),
+            "a server thread calls no client hook"
+        );
+        match &self.player_model {
+            Some(m) if engine::any() => {
+                engine::camera(&CameraView::new(m.age as f32 + partial)).map_or(1.0, |c| c.distance)
+            }
+            _ => 1.0,
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn sprite_locations_fit_the_buffer_and_differ_by_id() {
+        let mut a = [0; 22];
+        let mut b = [0; 22];
+        assert_eq!(location(u64::MAX, &mut a), "hooks/ffffffffffffffff");
+        assert_eq!(location(10, &mut b), "hooks/a");
+    }
 }

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

@@ -900,10 +900,12 @@ impl Game<'_> {
         let board = &self.score.board;
         let objective = board.display_objective(sb::SLOT_LIST);
         let up = |id: u128| upside_down.contains(&id);
-        // Horizon's mark before the names of Horizon players (the cosmetics service's cache).
-        let horizon = self.horizon_players(players.iter().map(|p| p.uuid));
-        let horizon_mark = super::cosmetics::MARK;
-        let marked = |id: u128| horizon.contains(&id).then_some(horizon_mark);
+        // A hook's mark before a name (Horizon's: they play Horizon).
+        debug_assert!(
+            self.serving.is_none(),
+            "a server thread calls no client hook"
+        );
+        let marked = horizon_hooks::engine::player_mark;
         let inputs = TabInputs {
             players: &players,
             board,

crates/horizon-hooks/src/lib.rs

@@ -44,14 +44,36 @@ pub trait Hooks: Sync {
     /// The game is ending normally: its window closed and the world is saved. Not after a crash.
     fn shutdown(&self) {}
 
-    /// Once a frame, before drawing. Only a window's game calls it (each splitscreen player in
-    /// turn, [`seat`]), never the integrated server's thread or a dedicated server.
-    fn frame(&self, _frame: &players::Frame) {}
+    /// Once a frame, before drawing: `sprites` takes the pictures the crate's
+    /// [`players::Sprites`] lacked. Only a window's game calls it (each splitscreen player in
+    /// turn, [`seat`]), never the integrated server's thread or a dedicated server; so are the
+    /// player methods below (not [`Hooks::tunnel`]).
+    fn frame(&self, _frame: &players::Frame, _sprites: &mut dyn players::SpriteStore) {}
 
-    /// Once a client tick while a world is shown: the player models in view. Called as
-    /// [`Hooks::frame`] is.
+    /// Once a client tick while a world is shown: the player models in view.
     fn tick(&self, _models: &mut dyn players::PlayerModels) {}
 
+    /// What goes by a player model's name over its head, each frame its name tag is drawn. The
+    /// first hook that answers is used.
+    fn name_decoration(
+        &self,
+        _model: &players::PlayerModel,
+        _sprites: &dyn players::Sprites,
+    ) -> Option<players::NameDecoration> {
+        None
+    }
+
+    /// The mark before the name of the player `uuid` in the player list, each frame it shows.
+    /// The first hook that answers is used.
+    fn player_mark(&self, _uuid: u128) -> Option<players::Mark> {
+        None
+    }
+
+    /// How the camera stands in third person, each frame. The first hook that answers is used.
+    fn camera(&self, _own: &players::CameraView) -> Option<players::CameraOverride> {
+        None
+    }
+
     /// 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.
@@ -163,12 +185,30 @@ pub mod engine {
     }
 
     /// [`Hooks::frame`].
-    pub fn frame(frame: &players::Frame) {
+    pub fn frame(frame: &players::Frame, sprites: &mut dyn players::SpriteStore) {
         for hooks in all() {
-            hooks.frame(frame);
+            hooks.frame(frame, sprites);
         }
     }
 
+    /// [`Hooks::name_decoration`].
+    pub fn name_decoration(
+        model: &players::PlayerModel,
+        sprites: &dyn players::Sprites,
+    ) -> Option<players::NameDecoration> {
+        all().iter().find_map(|h| h.name_decoration(model, sprites))
+    }
+
+    /// [`Hooks::player_mark`].
+    pub fn player_mark(uuid: u128) -> Option<players::Mark> {
+        all().iter().find_map(|h| h.player_mark(uuid))
+    }
+
+    /// [`Hooks::camera`].
+    pub fn camera(own: &players::CameraView) -> Option<players::CameraOverride> {
+        all().iter().find_map(|h| h.camera(own))
+    }
+
     /// [`Hooks::tick`].
     pub fn tick(models: &mut dyn players::PlayerModels) {
         for hooks in all() {
@@ -202,11 +242,29 @@ mod tests {
         fn published(&self, open: bool) {
             self.0.lock().unwrap().push(format!("published {open}"));
         }
-        fn frame(&self, frame: &players::Frame) {
+        fn frame(&self, frame: &players::Frame, sprites: &mut dyn players::SpriteStore) {
             self.0
                 .lock()
                 .unwrap()
                 .push(format!("frame {}", frame.connection));
+            if !sprites.has(1) {
+                sprites.put(1, vec![0; 64 * 64 * 4]);
+            }
+        }
+        fn name_decoration(
+            &self,
+            model: &players::PlayerModel,
+            sprites: &dyn players::Sprites,
+        ) -> Option<players::NameDecoration> {
+            let badge = sprites.get(1).map(|uv| players::Badge::new(uv, 0xFF0000));
+            (model.kind == players::Kind::Player)
+                .then(|| players::NameDecoration::new(Some(MARK), badge, Some(2.0)))
+        }
+        fn player_mark(&self, uuid: u128) -> Option<players::Mark> {
+            (uuid == 9).then_some(MARK)
+        }
+        fn camera(&self, own: &players::CameraView) -> Option<players::CameraOverride> {
+            Some(players::CameraOverride::new(own.age / 10.0))
         }
         fn tick(&self, models: &mut dyn players::PlayerModels) {
             let mut ids = Vec::new();
@@ -253,6 +311,25 @@ mod tests {
         }
     }
 
+    const MARK: players::Mark = &[(0, 0, 8, 8, 0xFF00_00FF)];
+
+    /// One sprite slot, as the game's atlas has many.
+    #[derive(Default)]
+    struct Atlas(Option<(u64, usize)>);
+    impl players::SpriteStore for Atlas {
+        fn has(&self, id: u64) -> bool {
+            self.0.is_some_and(|(i, _)| i == id)
+        }
+        fn put(&mut self, id: u64, rgba: Vec<u8>) {
+            self.0 = Some((id, rgba.len()));
+        }
+    }
+    impl players::Sprites for Atlas {
+        fn get(&self, id: u64) -> Option<[f32; 4]> {
+            players::SpriteStore::has(self, id).then_some([0.0, 0.0, 0.5, 0.5])
+        }
+    }
+
     /// Implements nothing: the defaults do nothing.
     struct Silent;
     impl Hooks for Silent {}
@@ -270,7 +347,23 @@ mod tests {
         }
         engine::shutdown();
         assert!(engine::any());
-        engine::frame(&players::Frame::new(4));
+        let mut atlas = Atlas::default();
+        let model = |kind| players::PlayerModel::new(5, kind, Some(9), 0, false);
+        // Before the frame put the sprite in: the decoration without its badge.
+        let before = engine::name_decoration(&model(players::Kind::Player), &atlas).unwrap();
+        assert!(before.badge.is_none() && before.top == Some(2.0));
+        engine::frame(&players::Frame::new(4, false), &mut atlas);
+        assert_eq!(atlas.0, Some((1, 64 * 64 * 4)));
+        let after = engine::name_decoration(&model(players::Kind::Player), &atlas).unwrap();
+        assert_eq!(
+            after.badge.map(|b| (b.uv, b.line)),
+            Some(([0.0, 0.0, 0.5, 0.5], 0xFF0000))
+        );
+        assert!(engine::name_decoration(&model(players::Kind::Mannequin), &atlas).is_none());
+        assert_eq!(engine::player_mark(9), Some(MARK));
+        assert_eq!(engine::player_mark(8), None);
+        let camera = engine::camera(&players::CameraView::new(5.0));
+        assert_eq!(camera.map(|c| c.distance), Some(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());

crates/horizon-hooks/src/players.rs

@@ -1,7 +1,7 @@
 //! The players the game shows, as a crate above the engine sees them (Horizon's emotes, spec
-//! #14091): [`PlayerModels`] in [`crate::Hooks::tick`], [`Frame`] in [`crate::Hooks::frame`], and
-//! [`BodyPose`], a pose laid over a player's body after its vanilla animation. Plain types only:
-//! no engine type crosses this line.
+//! #14091): [`PlayerModels`] in [`crate::Hooks::tick`], [`Frame`] in [`crate::Hooks::frame`],
+//! [`BodyPose`], a pose laid over a player's body after its vanilla animation, what goes by their
+//! names, and the crate's [`Sprites`]. Plain types only: no engine type crosses this line.
 use std::sync::Arc;
 
 /// The player model's parts a [`BodyPose`] poses, in its order.
@@ -44,12 +44,17 @@ pub struct PlayerModel {
     /// Its entity id on this connection ([`PlayerModels::connection`]).
     pub id: u32,
     pub kind: Kind,
-    /// The player's UUID as the server gave it; None for the window's own model and mannequins.
+    /// The player's UUID as the server gave it (the window's own: its profile); None for
+    /// mannequins.
     pub uuid: Option<u128>,
     /// Its age in ticks, the clock a [`BodyPose`] is timed on.
     pub age: u32,
     /// It moved sideways since the last tick (more than 0.01 blocks).
     pub moved: bool,
+    /// What it wears that covers a crate's drawing.
+    pub gear: Gear,
+    /// It is drawn invisible (the effect, or a trader's disguise).
+    pub invisible: bool,
 }
 
 impl PlayerModel {
@@ -60,8 +65,37 @@ impl PlayerModel {
             uuid,
             age,
             moved,
+            gear: Gear::default(),
+            invisible: false,
         }
     }
+
+    /// With what it wears and whether it is invisible.
+    pub fn looks(self, gear: Gear, invisible: bool) -> Self {
+        Self {
+            gear,
+            invisible,
+            ..self
+        }
+    }
+}
+
+/// What a player model wears where a crate may draw.
+#[derive(Clone, Copy, Debug, Default, PartialEq, Eq)]
+#[non_exhaustive]
+pub struct Gear {
+    /// A helmet or a head item.
+    pub head: bool,
+    /// A chestplate (an elytra is on the back).
+    pub chest: bool,
+    /// A cape or an elytra.
+    pub back: bool,
+}
+
+impl Gear {
+    pub fn new(head: bool, chest: bool, back: bool) -> Self {
+        Self { head, chest, back }
+    }
 }
 
 /// The player models of the world this window shows, once a tick ([`crate::Hooks::tick`]).
@@ -83,10 +117,96 @@ pub trait PlayerModels {
 pub struct Frame {
     /// As [`PlayerModels::connection`]; 0 with no world.
     pub connection: u64,
+    /// The world is the window's own single-player one: its server names the player by an
+    /// offline profile.
+    pub solo: bool,
 }
 
 impl Frame {
-    pub fn new(connection: u64) -> Self {
-        Self { connection }
+    pub fn new(connection: u64, solo: bool) -> Self {
+        Self { connection, solo }
+    }
+}
+
+/// Rectangles drawn before a name: x, y, width, height in text pixels from the name line's top
+/// left corner (a pixel left of its background), and `0xAARRGGBB`.
+pub type Mark = &'static [(u8, u8, u8, u8, u32)];
+
+/// What a crate draws by a player's name over their head ([`crate::Hooks::name_decoration`]).
+#[derive(Clone, Copy, Debug, Default)]
+#[non_exhaustive]
+pub struct NameDecoration {
+    /// Before the name.
+    pub mark: Option<Mark>,
+    /// After the name, and a line under it.
+    pub badge: Option<Badge>,
+    /// How high the crate's drawing on the body gets above the neck, in model pixels: the tag
+    /// goes up over it.
+    pub top: Option<f32>,
+}
+
+impl NameDecoration {
+    pub fn new(mark: Option<Mark>, badge: Option<Badge>, top: Option<f32>) -> Self {
+        Self { mark, badge, top }
+    }
+}
+
+/// A badge after a name: 8 text pixels square, a pixel right of the background.
+#[derive(Clone, Copy, Debug)]
+#[non_exhaustive]
+pub struct Badge {
+    /// Its picture: a part of a [`Sprites`] sprite, in atlas coordinates (u0, v0, u1, v1).
+    pub uv: [f32; 4],
+    /// The line under the name, `0xRRGGBB`.
+    pub line: u32,
+}
+
+impl Badge {
+    pub fn new(uv: [f32; 4], line: u32) -> Self {
+        Self { uv, line }
+    }
+}
+
+/// A crate's pictures in the game's atlas, by ids of its own: 64×64 RGBA each, in the slots skins
+/// use (one no frame drew for a while may go). Read while drawing.
+pub trait Sprites {
+    /// Where sprite `id` is (u0, v0, u1, v1), and it is kept this frame. None until
+    /// [`SpriteStore::put`] put it there.
+    fn get(&self, id: u64) -> Option<[f32; 4]>;
+}
+
+/// Where a crate puts its [`Sprites`], in [`crate::Hooks::frame`].
+pub trait SpriteStore {
+    /// Sprite `id` is in the atlas.
+    fn has(&self, id: u64) -> bool;
+    /// Puts sprite `id` in the atlas (64×64 RGBA), if a slot is free.
+    fn put(&mut self, id: u64, rgba: Vec<u8>);
+}
+
+/// The window's own model, as [`crate::Hooks::camera`] sees it.
+#[derive(Clone, Copy, Debug)]
+#[non_exhaustive]
+pub struct CameraView {
+    /// Its age in ticks, with the frame's part of a tick.
+    pub age: f32,
+}
+
+impl CameraView {
+    pub fn new(age: f32) -> Self {
+        Self { age }
+    }
+}
+
+/// How a crate moves the camera in third person.
+#[derive(Clone, Copy, Debug)]
+#[non_exhaustive]
+pub struct CameraOverride {
+    /// How far it stands back, as a share of the usual distance.
+    pub distance: f32,
+}
+
+impl CameraOverride {
+    pub fn new(distance: f32) -> Self {
+        Self { distance }
     }
 }

crates/horizon-platform/src/lib.rs

@@ -47,9 +47,11 @@ pub use horizon_server_files as server_files;
 /// in"). The engine's dispatch side is not part of the API.
 pub mod hooks {
     /// The players the game shows (`horizon_hooks::players`): the views [`Hooks::frame`] and
-    /// [`Hooks::tick`] get, and the pose a crate lays over a player's body.
+    /// [`Hooks::tick`] get, the pose a crate lays over a player's body, what goes by their names,
+    /// the crate's sprites and the camera.
     pub use horizon_hooks::players::{
-        BODY_PARTS, BodyPose, Frame, Kind, PlayerModel, PlayerModels,
+        BODY_PARTS, Badge, BodyPose, CameraOverride, CameraView, Frame, Gear, Kind, Mark,
+        NameDecoration, PlayerModel, PlayerModels, SpriteStore, Sprites,
     };
     pub use horizon_hooks::{Hooks, Started, TooLate, register, seat, tunnel};
 }