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9b7a965667
This proves a flag in msl::PipelineOptions that attempts to write all Metal vertex entry points to use a vertex pulling technique. It does this by: 1) Forcing the _buffer_sizes structure to be generated for all vertex entry points. The structure has additional buffer_size members that contain the byte sizes of the vertex buffers. 2) Adding new args to vertex entry points for the vertex id and/or the instance id and for the bound buffers. If there is an existing @builtin(vertex_index) or @builtin(instance_index) param, then no duplicate arg is created. 3) Adding code at the beginning of the function for vertex entry points to compare the vertex id or instance id against the lengths of all the bound buffers, and force an early-exit if the bounds are violated. 4) Extracting the raw bytes from the vertex buffer(s) and unpacking those bytes into the bound attributes with the expected types. 5) Replacing the varyings input and instead using the unpacked attributes to fill any structs-as-args that are rebuilt in the entry point. A new naga test is added which exercises this flag and demonstrates the effect of the transform. The msl generated by this test passes validation. Eventually this transformation will be the default, always-on behavior for Metal pipelines, though the flag may remain so that naga translation tests can be run with and without the tranformation.
33 lines
766 B
WebGPU Shading Language
33 lines
766 B
WebGPU Shading Language
struct VertexOutput {
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@builtin(position) position: vec4<f32>,
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@location(0) color: vec4<f32>,
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@location(1) texcoord: vec2<f32>,
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}
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struct VertexInput {
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@location(0) position: vec4<f32>,
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@location(1) normal: vec3<f32>,
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@location(2) texcoord: vec2<f32>,
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}
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@group(0) @binding(0) var<uniform> mvp_matrix: mat4x4<f32>;
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@vertex
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fn render_vertex(
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v_in: VertexInput,
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@builtin(vertex_index) v_existing_id: u32,
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) -> VertexOutput
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{
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var v_out: VertexOutput;
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v_out.position = v_in.position * mvp_matrix;
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v_out.color = do_lighting(v_in.position,
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v_in.normal);
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v_out.texcoord = v_in.texcoord;
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return v_out;
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}
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fn do_lighting(position: vec4<f32>, normal: vec3<f32>) -> vec4<f32> {
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// blah blah blah
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return vec4<f32>(0);
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}
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