Function computeRedCentroidFromTexture

e2e/webgpu-render.spec.ts:502–594

(
        texture: BrowserGpuTexture
      )

      });

      const computeRedCentroidFromTexture = async (
        texture: BrowserGpuTexture
      ): Promise<BrowserTextureCentroid> => {
        const pixelCount = width * height;
        const compareWorkgroupCount = Math.ceil(pixelCount / centroidWorkgroupSize);
        const partialByteLength = compareWorkgroupCount * 4 * Uint32Array.BYTES_PER_ELEMENT;
        const partialA = device!.createBuffer({
          size: partialByteLength,
          usage: bufferUsageStorage | bufferUsageCopySrc,
        });
        const partialB = device!.createBuffer({
          size: partialByteLength,
          usage: bufferUsageStorage | bufferUsageCopySrc,
        });
        const readbackBuffer = device!.createBuffer({
          size: 4 * Uint32Array.BYTES_PER_ELEMENT,
          usage: bufferUsageMapRead | bufferUsageCopyDst,
        });
        const paramsBuffers: BrowserGpuBuffer[] = [];

        try {
          const commandEncoder = device!.createCommandEncoder();
          const compareParams = createAndWriteUniformBuffer(new Uint32Array([width, height, 0, 0]));
          paramsBuffers.push(compareParams);
          const compareBindGroup = device!.createBindGroup({
            layout: centroidComparePipeline.getBindGroupLayout(0),
            entries: [
              { binding: 0, resource: texture.createView() },
              { binding: 1, resource: { buffer: partialA } },
              { binding: 2, resource: { buffer: compareParams } },
            ],
          });

          const comparePass = commandEncoder.beginComputePass();
          comparePass.setPipeline(centroidComparePipeline);
          comparePass.setBindGroup(0, compareBindGroup);
          comparePass.dispatchWorkgroups(compareWorkgroupCount);
          comparePass.end();

          let inputBuffer = partialA;
          let outputBuffer = partialB;
          let inputCount = compareWorkgroupCount;
          while (inputCount > 1) {
            const outputCount = Math.ceil(inputCount / centroidWorkgroupSize);
            const reduceParams = createAndWriteUniformBuffer(new Uint32Array([inputCount, 0, 0, 0]));
            paramsBuffers.push(reduceParams);
            const reduceBindGroup = device!.createBindGroup({
              layout: centroidReducePipeline.getBindGroupLayout(0),
              entries: [
                { binding: 0, resource: { buffer: inputBuffer } },
                { binding: 1, resource: { buffer: outputBuffer } },
                { binding: 2, resource: { buffer: reduceParams } },
              ],
            });
            const reducePass = commandEncoder.beginComputePass();
            reducePass.setPipeline(centroidReducePipeline);
            reducePass.setBindGroup(0, reduceBindGroup);
            reducePass.dispatchWorkgroups(outputCount);