GPURenderBundle

Limited availability

This feature is not Baseline because it does not work in some of the most widely-used browsers.

Secure context: This feature is available only insecure contexts (HTTPS), in some or allsupporting browsers.

Note: This feature is available inWeb Workers.

TheGPURenderBundle interface of theWebGPU API represents a container for pre-recorded bundles of commands.

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

These command bundles can then be reused across multiple render passes by passing theGPURenderBundle objects intoGPURenderPassEncoder.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 inGPUError messages or console warnings.

Examples

In the WebGPU SamplesAnimometer example, a lot of like operations are done on many different objects simultaneously. A render bundle 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, aGPURenderBundleEncoder is created, the function is invoked, and the render bundle is recorded usingGPURenderBundleEncoder.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()]);};// …