Function createCentroidCompareShader

e2e/webgpu-render.spec.ts:380–436

()

      };

      const createCentroidCompareShader = () => `
struct Params {
  width: u32,
  height: u32,
}

@group(0) @binding(0) var renderedTexture: texture_2d<f32>;
@group(0) @binding(1) var<storage, read_write> partials: array<vec4<u32>>;
@group(0) @binding(2) var<uniform> params: Params;

var<workgroup> partialSums: array<vec4<u32>, ${centroidWorkgroupSize}>;

fn addPartial(a: vec4<u32>, b: vec4<u32>) -> vec4<u32> {
  return vec4<u32>(a.x + b.x, a.y + b.y, a.z + b.z, a.w + b.w);
}

@compute @workgroup_size(${centroidWorkgroupSize})
fn main(
  @builtin(global_invocation_id) globalId: vec3<u32>,
  @builtin(local_invocation_id) localId: vec3<u32>,
  @builtin(workgroup_id) workgroupId: vec3<u32>
) {
  let pixelIndex = globalId.x;
  let pixelCount = params.width * params.height;
  var partial = vec4<u32>(0u, 0u, 0u, 0u);

  if (pixelIndex < pixelCount) {
    let x = pixelIndex % params.width;
    let y = pixelIndex / params.width;
    let color = textureLoad(renderedTexture, vec2<i32>(i32(x), i32(y)), 0);
    let red = u32(round(clamp(color.r, 0.0, 1.0) * 255.0));
    if (red > 0u) {
      partial = vec4<u32>(red, red * x, red * y, 1u);
    }
  }

  partialSums[localId.x] = partial;
  workgroupBarrier();

  var stride = ${centroidWorkgroupSize / 2}u;
  loop {
    if (localId.x < stride) {
      partialSums[localId.x] = addPartial(partialSums[localId.x], partialSums[localId.x + stride]);
    }
    workgroupBarrier();

    if (stride == 1u) {
      break;
    }
    stride = stride / 2u;
  }

  if (localId.x == 0u) {
    partials[workgroupId.x] = partialSums[0];
  }
}
`;