1// Types needed for GPU mesh uniform building.
2
3#define_import_path bevy_pbr::mesh_preprocess_types
4
5// Per-frame data that the CPU supplies to the GPU.
6struct MeshInput {
7    // The model transform.
8    world_from_local: mat3x4<f32>,
9    // The lightmap UV rect, packed into 64 bits.
10    lightmap_uv_rect: vec2<u32>,
11    // Various flags.
12    flags: u32,
13    previous_input_index: u32,
14    first_vertex_index: u32,
15    first_index_index: u32,
16    index_count: u32,
17    current_skin_index: u32,
18    // Low 16 bits: index of the material inside the bind group data.
19    // High 16 bits: index of the lightmap in the binding array.
20    material_and_lightmap_bind_group_slot: u32,
21    timestamp: u32,
22    // User supplied index to identify the mesh instance
23    tag: u32,
24    // The index of the morph descriptor for this mesh instance in the
25    // `morph_descriptors` table.
26    //
27    // If the mesh has no morph targets, this is `u32::MAX`.
28    morph_descriptor_index: u32,
29}
30
31// The `wgpu` indirect parameters structure. This is a union of two structures.
32// For more information, see the corresponding comment in
33// `gpu_preprocessing.rs`.
34struct IndirectParametersIndexed {
35    // `vertex_count` or `index_count`.
36    index_count: u32,
37    // `instance_count` in both structures.
38    instance_count: u32,
39    // `first_vertex` or `first_index`.
40    first_index: u32,
41    // `base_vertex` or `first_instance`.
42    base_vertex: u32,
43    // A read-only copy of `instance_index`.
44    first_instance: u32,
45}
46
47struct IndirectParametersNonIndexed {
48    vertex_count: u32,
49    instance_count: u32,
50    base_vertex: u32,
51    first_instance: u32,
52}
53
54struct IndirectParametersCpuMetadata {
55    base_output_index: u32,
56    batch_set_index: u32,
57}
58
59struct IndirectParametersGpuMetadata {
60    mesh_index: u32,
61#ifdef WRITE_INDIRECT_PARAMETERS_METADATA
62    early_instance_count: atomic<u32>,
63    late_instance_count: atomic<u32>,
64#else   // WRITE_INDIRECT_PARAMETERS_METADATA
65    early_instance_count: u32,
66    late_instance_count: u32,
67#endif  // WRITE_INDIRECT_PARAMETERS_METADATA
68}
69
70struct IndirectBatchSet {
71    indirect_parameters_count: atomic<u32>,
72    indirect_parameters_base: u32,
73}
74
75// One invocation of this compute shader: i.e. one mesh instance in a view.
76struct PreprocessWorkItem {
77    // The index of the `MeshInput` in the `current_input` buffer that we read
78    // from.
79    input_index: u32,
80    // In direct mode, the index of the `Mesh` in `output` that we write to. In
81    // indirect mode, the index of the `IndirectParameters` in
82    // `indirect_parameters` that we write to.
83    output_or_indirect_parameters_index: u32,
84}