Split baked animation modules (#38)

Fixes #19

Splits the baked animation implementation into focused fixed-transform, runtime, visual-binding, and asset-baking modules behind the existing public facade. Preserves public APIs, serialized field order, TypePath, plugin registration, schedules, and runtime behavior.

Reviewed-on: #38
Co-authored-by: Álex Román Núñez <eirexe@eirteam.moe>

src/fighter/baked_animation/runtime.rs

@@ -0,0 +1,244 @@
+use std::collections::HashMap;
+
+use bevy::prelude::*;
+use serde::{Deserialize, Serialize};
+
+use super::{BAKED_ANIMATION_FPS};
+
+use crate::{
+    fighter::{
+        Fighter,
+        animation::{AnimKind, FighterAnimationFrame},
+        manifest::FighterManifest,
+        visual::FighterAnimations,
+    },
+    math::int::FGi32,
+    math::fixed_transform::FixedMat4
+};
+
+#[derive(Clone, Debug, Serialize, Deserialize)]
+pub struct BakedAnimationClip {
+    pub frames: Vec<Vec<FixedMat4>>,
+}
+
+#[derive(Asset, bevy::reflect::TypePath, Clone, Debug, Serialize, Deserialize)]
+#[type_path = "shinespark::fighter::baked_animation"]
+pub struct BakedFighterAnimations {
+    pub frame_rate: u32,
+    pub bone_names: Vec<String>,
+    pub parents: Vec<Option<usize>>,
+    pub(super) clips: Vec<BakedAnimationClip>,
+    pub(super) clip_indices: HashMap<AnimKind, usize>,
+}
+
+impl BakedFighterAnimations {
+    pub fn contains_bone(&self, bone: &str) -> bool {
+        self.bone_names.iter().any(|name| name == bone)
+    }
+    pub fn has_unique_bone_names(&self) -> bool {
+        let mut names = std::collections::HashSet::with_capacity(self.bone_names.len());
+        self.bone_names.iter().all(|name| names.insert(name))
+    }
+    pub fn sample_pose(&self, frame: &FighterAnimationFrame) -> Option<&[FixedMat4]> {
+        let frames = &self.clip(frame.kind)?.frames;
+        let frame_index = if frame.repeat {
+            let loop_frame_count = frames.len().saturating_sub(1).max(1) as u32;
+            frame.frame % loop_frame_count
+        } else {
+            frame.frame
+        };
+        frames
+            .get(frame_index as usize)
+            .or_else(|| frames.last())
+            .map(Vec::as_slice)
+    }
+    pub fn frame_count(&self, kind: AnimKind) -> Option<u32> {
+        self.clip(kind).map(|clip| clip.frames.len() as u32)
+    }
+    pub(super) fn clip(&self, kind: AnimKind) -> Option<&BakedAnimationClip> {
+        self.clip_indices
+            .get(&kind)
+            .and_then(|index| self.clips.get(*index))
+    }
+}
+
+#[derive(Component, Clone, Debug, Default)]
+pub struct FighterBoneMatrices {
+    bone_names: Vec<String>,
+    parents: Vec<Option<usize>>,
+    matrices: Vec<FixedMat4>,
+    previous_frame_matrices: Vec<FixedMat4>,
+    local_matrices: Vec<FixedMat4>,
+    previous_local_matrices: Vec<FixedMat4>,
+}
+
+#[derive(Component, Clone, Debug, Default)]
+pub struct FighterBoneIndexMap(pub HashMap<String, usize>);
+
+impl FighterBoneMatrices {
+    pub fn get(&self, bone: &str) -> Option<(FixedMat4, FixedMat4)> {
+        let index = self.bone_names.iter().position(|name| name == bone)?;
+        Some((
+            *self.previous_frame_matrices.get(index)?,
+            *self.matrices.get(index)?,
+        ))
+    }
+    pub fn get_current(&self, bone: &str) -> Option<FixedMat4> {
+        let index = self.bone_names.iter().position(|name| name == bone)?;
+        self.matrices.get(index).copied()
+    }
+    pub fn get_index(&self, index: usize) -> Option<(FixedMat4, FixedMat4)> {
+        Some((
+            *self.previous_frame_matrices.get(index)?,
+            *self.matrices.get(index)?,
+        ))
+    }
+    pub fn get_current_index(&self, index: usize) -> Option<FixedMat4> {
+        self.matrices.get(index).copied()
+    }
+    pub fn iter(&self) -> impl Iterator<Item = (&str, FixedMat4)> {
+        self.bone_names
+            .iter()
+            .map(String::as_str)
+            .zip(self.matrices.iter().copied())
+    }
+    pub fn local(&self, index: usize) -> Option<FixedMat4> {
+        self.local_matrices.get(index).copied()
+    }
+    pub(super) fn presentation_local(
+        &self,
+        index: usize,
+        overstep_fraction: f32,
+    ) -> Option<Transform> {
+        let current = self.local_matrices.get(index).copied()?;
+        let previous = self
+            .previous_local_matrices
+            .get(index)
+            .copied()
+            .unwrap_or(current);
+        Some(interpolate_transform(previous, current, overstep_fraction))
+    }
+    pub(super) fn set_pose(
+        &mut self,
+        bone_names: &[String],
+        parents: &[Option<usize>],
+        local: &[FixedMat4],
+        model_scale: FGi32,
+    ) {
+        assert_eq!(
+            bone_names.len(),
+            local.len(),
+            "baked animation pose does not match its bone names"
+        );
+        assert_eq!(
+            bone_names.len(),
+            parents.len(),
+            "baked bone parents do not match names"
+        );
+        if self.bone_names.is_empty() {
+            self.bone_names.extend_from_slice(bone_names);
+            self.parents.extend_from_slice(parents);
+        } else {
+            assert_eq!(self.bone_names, bone_names, "baked bone names changed");
+            assert_eq!(self.parents, parents, "baked bone parents changed");
+        }
+        std::mem::swap(&mut self.matrices, &mut self.previous_frame_matrices);
+        std::mem::swap(&mut self.local_matrices, &mut self.previous_local_matrices);
+        self.local_matrices.clear();
+        self.local_matrices.extend_from_slice(local);
+        let mut model = vec![None; local.len()];
+        for index in 0..local.len() {
+            resolve_model_transform(index, parents, local, &mut model)
+                .expect("baked bone hierarchy should be valid");
+        }
+        let model_scale = FixedMat4 {
+            cols: [
+                [model_scale, FGi32::ZERO, FGi32::ZERO, FGi32::ZERO],
+                [FGi32::ZERO, model_scale, FGi32::ZERO, FGi32::ZERO],
+                [FGi32::ZERO, FGi32::ZERO, model_scale, FGi32::ZERO],
+                [FGi32::ZERO, FGi32::ZERO, FGi32::ZERO, FGi32::ONE],
+            ],
+        };
+        self.matrices = model
+            .into_iter()
+            .map(|matrix| model_scale.mul(matrix.expect("baked bone hierarchy should be valid")))
+            .collect();
+    }
+}
+
+pub fn update_fighter_bone_matrices(
+    mut fighters: Query<(
+        &FighterAnimationFrame,
+        &FighterAnimations,
+        &Fighter,
+        &mut FighterBoneMatrices,
+        &mut FighterBoneIndexMap,
+    )>,
+    baked_assets: Res<Assets<BakedFighterAnimations>>,
+    manifests: Res<Assets<FighterManifest>>,
+) {
+    for (frame, animations, fighter, mut matrices, mut bone_indices) in &mut fighters {
+        let baked = baked_assets
+            .get(&animations.baked)
+            .expect("fighter baked animation asset should be loaded before the match starts");
+        assert_eq!(
+            baked.frame_rate, BAKED_ANIMATION_FPS,
+            "fighter baked animation rate does not match the simulation rate"
+        );
+        let pose = baked
+            .sample_pose(frame)
+            .expect("fighter animation frame should select a baked pose");
+        let manifest = manifests
+            .get(&fighter.manifest)
+            .expect("fighter manifest should be loaded before the match starts");
+        matrices.set_pose(
+            &baked.bone_names,
+            &baked.parents,
+            pose,
+            manifest.model_scale,
+        );
+        if bone_indices.0.is_empty() {
+            bone_indices.0.extend(
+                baked
+                    .bone_names
+                    .iter()
+                    .enumerate()
+                    .map(|(index, name)| (name.clone(), index)),
+            );
+        }
+    }
+}
+
+fn resolve_model_transform(
+    index: usize,
+    parents: &[Option<usize>],
+    local: &[FixedMat4],
+    model: &mut [Option<FixedMat4>],
+) -> std::io::Result<FixedMat4> {
+    if let Some(value) = model[index] {
+        return Ok(value);
+    }
+    let value = match parents[index] {
+        Some(parent) => resolve_model_transform(parent, parents, local, model)?.mul(local[index]),
+        None => local[index],
+    };
+    model[index] = Some(value);
+    Ok(value)
+}
+
+pub(super) fn interpolate_transform(
+    previous: FixedMat4,
+    current: FixedMat4,
+    factor: f32,
+) -> Transform {
+    let (previous_scale, previous_rotation, previous_translation) =
+        previous.to_mat4().to_scale_rotation_translation();
+    let (current_scale, current_rotation, current_translation) =
+        current.to_mat4().to_scale_rotation_translation();
+    let factor = factor.clamp(0.0, 1.0);
+    Transform {
+        translation: previous_translation.lerp(current_translation, factor),
+        rotation: previous_rotation.slerp(current_rotation, factor),
+        scale: previous_scale.lerp(current_scale, factor),
+    }
+}