GPUDevice: createRenderBundleEncoder() method - Web APIs

GPUDevice: createRenderBundleEncoder() method - Web APIs | MDN

Syntax

createRenderBundleEncoder(descriptor)

Parameters

descriptor

An object containing the following properties:

colorFormats: An array of enumerated values specifying the expected color formats for render targets. For possible values, see the GPUTextureFormat definition in the spec.
depthReadOnly Optional: A boolean. If true, specifies that executing any GPURenderBundle created by the GPURenderBundleEncoder will not modify the depth component of the depthStencilFormat when executed. If omitted, depthReadOnly will default to false.
depthStencilFormat Optional: An enumerated value that specifies the expected depth-or-stencil format for render targets. For possible values, see the Depth-stencil formats section of the spec.
label Optional: A string providing a label that can be used to identify the object, for example in GPUError messages or console warnings.
sampleCount Optional: A number representing the expected sample count for render targets.
stencilReadOnly Optional: A boolean. If true, specifies that executing any GPURenderBundle created by the GPURenderBundleEncoder will not modify the stencil component of the depthStencilFormat when executed. If omitted, stencilReadOnly will default to false.

Return value

A GPURenderBundleEncoder object instance.

Examples

In the WebGPU Samples Animometer example, numerous similar operations are done on many different objects simultaneously. A bundle of commands is encoded using the following function:

function recordRenderPass(
  passEncoder: GPURenderBundleEncoder | GPURenderPassEncoder
) {
  if (settings.dynamicOffsets) {
    passEncoder.setPipeline(dynamicPipeline);
  } else {
    passEncoder.setPipeline(pipeline);
  }
  passEncoder.setVertexBuffer(0, vertexBuffer);
  passEncoder.setBindGroup(0, timeBindGroup);
  const dynamicOffsets = [0];
  for (let i = 0; i < numTriangles; ++i) {
    if (settings.dynamicOffsets) {
      dynamicOffsets[0] = i * alignedUniformBytes;
      passEncoder.setBindGroup(1, dynamicBindGroup, dynamicOffsets);
    } else {
      passEncoder.setBindGroup(1, bindGroups[i]);
    }
    passEncoder.draw(3, 1, 0, 0);
  }
}

Later on, a GPURenderBundleEncoder is created using createRenderBundleEncoder(), the function is invoked, and the command bundle is recorded into a GPURenderBundle using GPURenderBundleEncoder.finish():

const renderBundleEncoder = device.createRenderBundleEncoder({
  colorFormats: [presentationFormat],
});
recordRenderPass(renderBundleEncoder);
const renderBundle = renderBundleEncoder.finish();

GPURenderPassEncoder.executeBundles() is then used to reuse the work across multiple render passes to improve performance. Study the example code listing for the full context.

// …

return function doDraw(timestamp) {
  if (startTime === undefined) {
    startTime = timestamp;
  }
  uniformTime[0] = (timestamp - startTime) / 1000;
  device.queue.writeBuffer(uniformBuffer, timeOffset, uniformTime.buffer);

  renderPassDescriptor.colorAttachments[0].view = context
    .getCurrentTexture()
    .createView();

  const commandEncoder = device.createCommandEncoder();
  const passEncoder = commandEncoder.beginRenderPass(renderPassDescriptor);

  if (settings.renderBundles) {
    passEncoder.executeBundles([renderBundle]);
  } else {
    recordRenderPass(passEncoder);
  }

  passEncoder.end();
  device.queue.submit([commandEncoder.finish()]);
};

// …