GPURenderBundle

Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

The GPURenderBundle interface of the WebGPU API represents a container for pre-recorded bundles of commands.

The command bundles are encoded using a GPURenderBundleEncoder; once the desired commands have been encoded, they are recorded into a GPURenderBundle object instance using the GPURenderBundleEncoder.finish() method.

These command bundles can then be reused across multiple render passes by passing the GPURenderBundle objects into GPURenderPassEncoder.executeBundles() calls. Reusing pre-recoded commands can significantly improve app performance in situations where JavaScript draw call overhead is a bottleneck. Render bundles are most effective in situations where a batch of objects will be drawn the same way across multiple views or frames, with the only differences being the buffer content being used (such as updated matrix uniforms).

A good example is VR rendering. Recording the rendering as a render bundle and then tweaking the view matrix and replaying it for each eye is a more efficient way to issue draw calls for both renderings of the scene.

Instance properties

label

A string providing a label that can be used to identify the object, for example in GPUError messages or console warnings.

Examples

In the WebGPU Samples Animometer example, a lot of like operations are done on many different objects simultaneously. A render bundle is encoded using the following function:

js

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, the function is invoked, and the render bundle is recorded using GPURenderBundleEncoder.finish():

js

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.

js

// ...

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()]);
};

// ...

Specifications

Specification
WebGPU
# gpurenderbundle

Browser compatibility

BCD tables only load in the browser

See also