goud_engine/ecs/components/skeleton2d/
mesh.rs

1//! Skeletal mesh types for bone-driven vertex deformation.
2//!
3//! A [`SkeletalMesh2D`] holds vertices with bone weight assignments.
4//! The skeletal animation system uses these weights to deform vertex
5//! positions each frame, storing results in `deformed_positions`.
6
7use crate::core::math::Vec2;
8use crate::ecs::Component;
9
10/// Influence of a single bone on a vertex.
11#[repr(C)]
12#[derive(Debug, Clone, Copy)]
13pub struct BoneWeight {
14    /// Index into [`Skeleton2D::bones`](super::Skeleton2D).
15    pub bone_id: u32,
16    /// Blend weight in `[0.0, 1.0]`. Weights for one vertex should sum to 1.
17    pub weight: f32,
18}
19
20/// A vertex in a skeletal mesh with bone weight assignments.
21#[derive(Debug, Clone)]
22pub struct SkeletalVertex {
23    /// Rest-pose (bind-pose) position.
24    pub position: Vec2,
25    /// Texture coordinates.
26    pub uv: Vec2,
27    /// Bone influences (typically up to 4).
28    pub weights: Vec<BoneWeight>,
29}
30
31/// Deformable 2D mesh driven by a [`Skeleton2D`](super::Skeleton2D).
32///
33/// The mesh stores rest-pose vertices and a parallel `deformed_positions`
34/// buffer that the [`deform_skeletal_meshes`](crate::ecs::systems::skeletal_animation)
35/// system fills each frame.
36#[derive(Debug, Clone)]
37pub struct SkeletalMesh2D {
38    /// Rest-pose vertices with bone weights.
39    pub vertices: Vec<SkeletalVertex>,
40    /// Triangle indices into `vertices`.
41    pub indices: Vec<u16>,
42    /// Output buffer: deformed vertex positions (same length as `vertices`).
43    pub deformed_positions: Vec<Vec2>,
44}
45
46impl Component for SkeletalMesh2D {}
47
48impl SkeletalMesh2D {
49    /// Creates a new skeletal mesh, initialising deformed positions from rest pose.
50    pub fn new(vertices: Vec<SkeletalVertex>, indices: Vec<u16>) -> Self {
51        let deformed_positions = vertices.iter().map(|v| v.position).collect();
52        Self {
53            vertices,
54            indices,
55            deformed_positions,
56        }
57    }
58}
goud_engine/ecs/components/skeleton2d/mesh.rs

goud_engine/ecs/components/skeleton2d/
mesh.rs
