GPURenderPassEncoder: beginOcclusionQuery() method

The beginOcclusionQuery() method of the GPURenderPassEncoder interface begins an occlusion query at the specified index of the relevant GPUQuerySet (provided as the value of the occlusionQuerySet descriptor property when invoking GPUCommandEncoder.beginRenderPass() to run the render pass).

Syntax

beginOcclusionQuery(queryIndex)

Parameters

queryIndex

The index in the GPUQuerySet to begin the occlusion query at.

Return value

None (Undefined).

Validation

The following criteria must be met when calling beginOcclusionQuery(), otherwise a GPUValidationError is generated and the GPURenderPassEncoder becomes invalid:

• A GPUQuerySet was specified in the occlusionQuerySet descriptor property when invoking the originating GPUCommandEncoder.beginRenderPass().
• queryIndex is smaller than GPUQuerySet.count.
• The queryIndex has not already been written to in the same render pass.
• An occlusion query is not already active for this render pass (i.e., via a previous beginOcclusionQuery() call).

Examples

// …

// Create a query set to hold the occlusion queries
const querySet = device.createQuerySet({
  type: "occlusion",
  count: 32,
});

// Render pass descriptor object, including the querySet
const renderPassDescriptor = {
  colorAttachments: [
    {
      clearValue: clearColor,
      loadOp: "clear",
      storeOp: "store",
      view: context.getCurrentTexture().createView(),
    },
  ],
  occlusionQuerySet: querySet,
};

// Begin the render pass
const passEncoder = commandEncoder.beginRenderPass(renderPassDescriptor);

// Begin an occlusion query at index 0
passEncoder.beginOcclusionQuery(0);

// Run some rendering commands
passEncoder.setPipeline(renderPipeline);
passEncoder.setVertexBuffer(0, vertexBuffer);
passEncoder.draw(3);

// End the occlusion query
passEncoder.endOcclusionQuery();

// …

Specifications

Browser compatibility

See also

• The WebGPU API