bevy/crates/bevy_pbr/src/meshlet/meshlet_bindings.wgsl
JMS55 e1a0da0fa6
Meshlet LOD-compatible two-pass occlusion culling (#12898)
Keeping track of explicit visibility per cluster between frames does not
work with LODs, and leads to worse culling (using the final depth buffer
from the previous frame is more accurate).

Instead, we need to generate a second depth pyramid after the second
raster pass, and then use that in the first culling pass in the next
frame to test if a cluster would have been visible last frame or not.

As part of these changes, the write_index_buffer pass has been folded
into the culling pass for a large performance gain, and to avoid
tracking a lot of extra state that would be needed between passes.

Prepass previous model/view stuff was adapted to work with meshlets as
well.

Also fixed a bug with materials, and other misc improvements.

---------

Co-authored-by: François <mockersf@gmail.com>
Co-authored-by: atlas dostal <rodol@rivalrebels.com>
Co-authored-by: vero <email@atlasdostal.com>
Co-authored-by: Patrick Walton <pcwalton@mimiga.net>
Co-authored-by: Robert Swain <robert.swain@gmail.com>
2024-04-28 05:30:20 +00:00

115 lines
5.4 KiB
WebGPU Shading Language

#define_import_path bevy_pbr::meshlet_bindings
#import bevy_pbr::mesh_types::Mesh
#import bevy_render::view::View
#import bevy_pbr::prepass_bindings::PreviousViewUniforms
struct PackedMeshletVertex {
a: vec4<f32>,
b: vec4<f32>,
tangent: vec4<f32>,
}
// TODO: Octahedral encode normal, remove tangent and derive from UV derivatives
struct MeshletVertex {
position: vec3<f32>,
normal: vec3<f32>,
uv: vec2<f32>,
tangent: vec4<f32>,
}
fn unpack_meshlet_vertex(packed: PackedMeshletVertex) -> MeshletVertex {
var vertex: MeshletVertex;
vertex.position = packed.a.xyz;
vertex.normal = vec3(packed.a.w, packed.b.xy);
vertex.uv = packed.b.zw;
vertex.tangent = packed.tangent;
return vertex;
}
struct Meshlet {
start_vertex_id: u32,
start_index_id: u32,
triangle_count: u32,
}
struct MeshletBoundingSpheres {
self_culling: MeshletBoundingSphere,
self_lod: MeshletBoundingSphere,
parent_lod: MeshletBoundingSphere,
}
struct MeshletBoundingSphere {
center: vec3<f32>,
radius: f32,
}
struct DrawIndirectArgs {
vertex_count: atomic<u32>,
instance_count: u32,
first_vertex: u32,
first_instance: u32,
}
#ifdef MESHLET_CULLING_PASS
@group(0) @binding(0) var<storage, read> meshlet_thread_meshlet_ids: array<u32>; // Per cluster (instance of a meshlet)
@group(0) @binding(1) var<storage, read> meshlet_bounding_spheres: array<MeshletBoundingSpheres>; // Per asset meshlet
@group(0) @binding(2) var<storage, read> meshlet_thread_instance_ids: array<u32>; // Per cluster (instance of a meshlet)
@group(0) @binding(3) var<storage, read> meshlet_instance_uniforms: array<Mesh>; // Per entity instance
@group(0) @binding(4) var<storage, read> meshlet_view_instance_visibility: array<u32>; // 1 bit per entity instance, packed as a bitmask
@group(0) @binding(5) var<storage, read_write> meshlet_second_pass_candidates: array<atomic<u32>>; // 1 bit per cluster (instance of a meshlet), packed as a bitmask
@group(0) @binding(6) var<storage, read> meshlets: array<Meshlet>; // Per asset meshlet
@group(0) @binding(7) var<storage, read_write> draw_indirect_args: DrawIndirectArgs; // Single object shared between all workgroups/meshlets/triangles
@group(0) @binding(8) var<storage, read_write> draw_triangle_buffer: array<u32>; // Single object shared between all workgroups/meshlets/triangles
@group(0) @binding(9) var depth_pyramid: texture_2d<f32>; // From the end of the last frame for the first culling pass, and from the first raster pass for the second culling pass
@group(0) @binding(10) var<uniform> view: View;
@group(0) @binding(11) var<uniform> previous_view: PreviousViewUniforms;
fn should_cull_instance(instance_id: u32) -> bool {
let bit_offset = instance_id % 32u;
let packed_visibility = meshlet_view_instance_visibility[instance_id / 32u];
return bool(extractBits(packed_visibility, bit_offset, 1u));
}
fn meshlet_is_second_pass_candidate(cluster_id: u32) -> bool {
let packed_candidates = meshlet_second_pass_candidates[cluster_id / 32u];
let bit_offset = cluster_id % 32u;
return bool(extractBits(packed_candidates, bit_offset, 1u));
}
#endif
#ifdef MESHLET_VISIBILITY_BUFFER_RASTER_PASS
@group(0) @binding(0) var<storage, read> meshlet_thread_meshlet_ids: array<u32>; // Per cluster (instance of a meshlet)
@group(0) @binding(1) var<storage, read> meshlets: array<Meshlet>; // Per asset meshlet
@group(0) @binding(2) var<storage, read> meshlet_indices: array<u32>; // Many per asset meshlet
@group(0) @binding(3) var<storage, read> meshlet_vertex_ids: array<u32>; // Many per asset meshlet
@group(0) @binding(4) var<storage, read> meshlet_vertex_data: array<PackedMeshletVertex>; // Many per asset meshlet
@group(0) @binding(5) var<storage, read> meshlet_thread_instance_ids: array<u32>; // Per cluster (instance of a meshlet)
@group(0) @binding(6) var<storage, read> meshlet_instance_uniforms: array<Mesh>; // Per entity instance
@group(0) @binding(7) var<storage, read> meshlet_instance_material_ids: array<u32>; // Per entity instance
@group(0) @binding(8) var<storage, read> draw_triangle_buffer: array<u32>; // Single object shared between all workgroups/meshlets/triangles
@group(0) @binding(9) var<uniform> view: View;
fn get_meshlet_index(index_id: u32) -> u32 {
let packed_index = meshlet_indices[index_id / 4u];
let bit_offset = (index_id % 4u) * 8u;
return extractBits(packed_index, bit_offset, 8u);
}
#endif
#ifdef MESHLET_MESH_MATERIAL_PASS
@group(1) @binding(0) var meshlet_visibility_buffer: texture_2d<u32>; // Generated from the meshlet raster passes
@group(1) @binding(1) var<storage, read> meshlet_thread_meshlet_ids: array<u32>; // Per cluster (instance of a meshlet)
@group(1) @binding(2) var<storage, read> meshlets: array<Meshlet>; // Per asset meshlet
@group(1) @binding(3) var<storage, read> meshlet_indices: array<u32>; // Many per asset meshlet
@group(1) @binding(4) var<storage, read> meshlet_vertex_ids: array<u32>; // Many per asset meshlet
@group(1) @binding(5) var<storage, read> meshlet_vertex_data: array<PackedMeshletVertex>; // Many per asset meshlet
@group(1) @binding(6) var<storage, read> meshlet_thread_instance_ids: array<u32>; // Per cluster (instance of a meshlet)
@group(1) @binding(7) var<storage, read> meshlet_instance_uniforms: array<Mesh>; // Per entity instance
fn get_meshlet_index(index_id: u32) -> u32 {
let packed_index = meshlet_indices[index_id / 4u];
let bit_offset = (index_id % 4u) * 8u;
return extractBits(packed_index, bit_offset, 8u);
}
#endif