#include oct_encoding.wgsl
#include skin.wgsl

struct SkinningUniform {
  transform: mat4x4<f32>,
  src_offset: u32,
  dst_offset: u32,
  count: u32,
};

@group(0) @binding(0)
var<storage,read> skinning_ubo: SkinningUniform;

@group(0) @binding(1)
var<storage,write> dst_vertices: SkinnedVertexArray;

@group(0) @binding(2)
var<storage,read> src_vertices: SkinnedVertexArray;

@compute
@workgroup_size(64)
fn cs_main(
  @builtin(global_invocation_id) global_invocation_id: vec3<u32>,
) {
  let vertex_index = global_invocation_id.x;
  if (vertex_index >= skinning_ubo.count) {
    return;
  }

  let src_index = skinning_ubo.src_offset + vertex_index;
  let dst_index = skinning_ubo.dst_offset + vertex_index;

  let ptf = src_vertices.data[src_index].ptf;
  let position = ptf.xyz;
  let tan_frame = bitcast<u32>(ptf.w);

  let transform = skinning_ubo.transform;
  let position = transform * vec4<f32>(position, 1.0);
  let tan_frame = tan_frame_transform(tan_frame, transform);

  let dst_ptf = vec4<f32>(position.xyz, bitcast<f32>(tan_frame));
  dst_vertices.data[dst_index].ptf = dst_ptf;
}