forestiles/assets/render/skinning.wgsl
2025-07-20 12:00:43 +02:00

96 lines
3.1 KiB
WebGPU Shading Language

#define_import_path bevy_pbr::skinning
#import bevy_pbr::mesh_types::SkinnedMesh
#import bevy_pbr::mesh_bindings::mesh
#ifdef SKINNED
#ifdef SKINS_USE_UNIFORM_BUFFERS
@group(2) @binding(1) var<uniform> joint_matrices: SkinnedMesh;
#else // SKINS_USE_UNIFORM_BUFFERS
@group(2) @binding(1) var<storage> joint_matrices: array<mat4x4<f32>>;
#endif // SKINS_USE_UNIFORM_BUFFERS
// An array of matrices specifying the joint positions from the previous frame.
//
// This is used for motion vector computation.
//
// If this is the first frame, or we're otherwise prevented from using data from
// the previous frame, this is simply the same as `joint_matrices` above.
#ifdef SKINS_USE_UNIFORM_BUFFERS
@group(2) @binding(6) var<uniform> prev_joint_matrices: SkinnedMesh;
#else // SKINS_USE_UNIFORM_BUFFERS
@group(2) @binding(6) var<storage> prev_joint_matrices: array<mat4x4<f32>>;
#endif // SKINS_USE_UNIFORM_BUFFERS
fn skin_model(
indexes: vec4<u32>,
weights: vec4<f32>,
instance_index: u32,
) -> mat4x4<f32> {
#ifdef SKINS_USE_UNIFORM_BUFFERS
return weights.x * joint_matrices.data[indexes.x]
+ weights.y * joint_matrices.data[indexes.y]
+ weights.z * joint_matrices.data[indexes.z]
+ weights.w * joint_matrices.data[indexes.w];
#else // SKINS_USE_UNIFORM_BUFFERS
var skin_index = mesh[instance_index].current_skin_index;
return weights.x * joint_matrices[skin_index + indexes.x]
+ weights.y * joint_matrices[skin_index + indexes.y]
+ weights.z * joint_matrices[skin_index + indexes.z]
+ weights.w * joint_matrices[skin_index + indexes.w];
#endif // SKINS_USE_UNIFORM_BUFFERS
}
// Returns the skinned position of a vertex with the given weights from the
// previous frame.
//
// This is used for motion vector computation.
fn skin_prev_model(
indexes: vec4<u32>,
weights: vec4<f32>,
instance_index: u32,
) -> mat4x4<f32> {
#ifdef SKINS_USE_UNIFORM_BUFFERS
return weights.x * prev_joint_matrices.data[indexes.x]
+ weights.y * prev_joint_matrices.data[indexes.y]
+ weights.z * prev_joint_matrices.data[indexes.z]
+ weights.w * prev_joint_matrices.data[indexes.w];
#else // SKINS_USE_UNIFORM_BUFFERS
let skin_index = mesh[instance_index].current_skin_index;
return weights.x * prev_joint_matrices[skin_index + indexes.x]
+ weights.y * prev_joint_matrices[skin_index + indexes.y]
+ weights.z * prev_joint_matrices[skin_index + indexes.z]
+ weights.w * prev_joint_matrices[skin_index + indexes.w];
#endif // SKINS_USE_UNIFORM_BUFFERS
}
fn inverse_transpose_3x3m(in: mat3x3<f32>) -> mat3x3<f32> {
let x = cross(in[1], in[2]);
let y = cross(in[2], in[0]);
let z = cross(in[0], in[1]);
let det = dot(in[2], z);
return mat3x3<f32>(
x / det,
y / det,
z / det
);
}
fn skin_normals(
world_from_local: mat4x4<f32>,
normal: vec3<f32>,
) -> vec3<f32> {
return normalize(
inverse_transpose_3x3m(
mat3x3<f32>(
world_from_local[0].xyz,
world_from_local[1].xyz,
world_from_local[2].xyz
)
) * normal
);
}
#endif