GPUDevice: createQuerySet() method

The createQuerySet() method of the GPUDevice interface creates a GPUQuerySet that can be used to record the results of queries on passes, such as occlusion or timestamp queries.

Syntax

createQuerySet(descriptor)

Parameters

descriptor

An object containing the following properties:

count

A number specifying the number of queries to be managed by the resulting GPUQuerySet.

label Optional

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

type

An enumerated value specifying the type of queries to be managed by the resulting GPUQuerySet. Possible values are:

"occlusion"

Occlusion queries are available on render passes to query the number of fragment samples that pass all the per-fragment tests for a set of drawing commands (including scissor, sample mask, alpha to coverage, stencil, and depth tests). To run an occlusion query, an appropriate GPUQuerySet must be provided as the value of the occlusionQuerySet descriptor property when invoking GPUCommandEncoder.beginRenderPass() to run a render pass.

"timestamp"

Timestamp queries allow applications to write timestamps to a GPUQuerySet. To run a timestamp query, appropriate GPUQuerySets must be provided inside the value of the timestampWrites descriptor property when invoking GPUCommandEncoder.beginRenderPass() to run a render pass, or GPUCommandEncoder.beginComputePass() to run a compute pass. Alternatively, you can run a single timestamp query at any time by invoking GPUCommandEncoder.writeTimeStamp() with an appropriate GPUQuerySet as a parameter.

Note: The timestamp-query feature needs to be enabled to use timestamp queries.

Return value

A GPUQuerySet object instance.

Validation

The following criteria must be met when calling createQuerySet(), otherwise a GPUValidationError is generated and an invalid GPUQuerySet object is returned:

• count is less than or equal to 4096.

Examples

The following snippet creates a GPUQuerySet that holds 32 occlusion query results:

const querySet = device.createQuerySet({
  type: "occlusion",
  count: 32,
});

Specifications

Browser compatibility

See also

• The WebGPU API