GPUDevice: createRenderBundleEncoder() method
=============================================

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

 The **`createRenderBundleEncoder()`** method of the
 `GPUDevice` interface creates a `GPURenderBundleEncoder` that can be used to pre-record bundles of commands. These can be reused in `GPURenderPassEncoder`s via the `executeBundles()` method, as many times as required.

Syntax
------


```js
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:


```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 using `createRenderBundleEncoder()`, the function is invoked, and the command bundle is recorded into a `GPURenderBundle` 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 # dom-gpudevice-createrenderbundleencoder |

Browser compatibility
---------------------

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See also
--------

* The WebGPU API