68 lines
2.3 KiB
Rust
68 lines
2.3 KiB
Rust
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use naga::{Binding, ShaderStage, TypeInner};
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const MESH_SHADER: &str = include_str!("../src/shaders/mesh.wgsl");
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const WEBGL_INTER_STAGE_COMPONENT_LIMIT: u32 = 31;
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fn validate(source: &str) -> naga::Module {
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let module = naga::front::wgsl::parse_str(source).expect("mesh WGSL must parse");
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naga::valid::Validator::new(
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naga::valid::ValidationFlags::all(),
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naga::valid::Capabilities::empty(),
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)
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.validate(&module)
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.expect("mesh WGSL must validate");
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module
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}
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fn location_components(module: &naga::Module, type_name: &str) -> u32 {
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let ty = module
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.types
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.iter()
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.find_map(|(_, ty)| (ty.name.as_deref() == Some(type_name)).then_some(ty))
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.unwrap_or_else(|| panic!("{type_name} missing"));
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let TypeInner::Struct { members, .. } = &ty.inner else {
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panic!("{type_name} must remain a struct");
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};
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members
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.iter()
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.filter(|member| matches!(member.binding, Some(Binding::Location { .. })))
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.map(|member| match module.types[member.ty].inner {
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TypeInner::Scalar(_) => 1,
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TypeInner::Vector { size, .. } => u32::from(size),
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ref other => panic!("unsupported inter-stage type: {other:?}"),
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})
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.sum()
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}
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fn assert_edge_contract(source: &str) {
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let module = validate(source);
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assert!(module
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.entry_points
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.iter()
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.any(|entry| entry.stage == ShaderStage::Vertex && entry.name == "vs_edge"));
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assert!(module
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.entry_points
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.iter()
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.any(|entry| entry.stage == ShaderStage::Fragment && entry.name == "fs_edge"));
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let components = location_components(&module, "EdgeVertexOut");
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assert_eq!(components, 4, "edge output should carry only RGBA color");
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assert!(
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components <= WEBGL_INTER_STAGE_COMPONENT_LIMIT,
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"edge output exceeds WebGL2's inter-stage component budget"
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);
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}
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#[test]
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fn native_mesh_edge_shader_stays_webgl_compatible() {
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assert_edge_contract(MESH_SHADER);
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}
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#[test]
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fn storage_free_mesh_edge_shader_stays_webgl_compatible() {
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let compat = MESH_SHADER.replace(
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"var<storage, read> mesh_instances: array<MeshInstance>;",
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"var<uniform> mesh_instances: array<MeshInstance, 1>;",
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);
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assert_edge_contract(&compat);
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}
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