WebGL2RenderingContext.beginQuery

The WebGL2RenderingContext.beginQuery() method of the WebGL 2 API starts an asynchronous query. The target parameter indicates which kind of query to begin.

Syntax

void gl.beginQuery(target, query);

Parameters

target

A GLenum specifying the target of the query. Possible values:

• gl.ANY_SAMPLES_PASSED: Specifies an occlusion query: these queries detect whether an object is visible (whether the scoped drawing commands pass the depth test and if so, how many samples pass).
• gl.ANY_SAMPLES_PASSED_CONSERVATIVE: Same as above above, but less accurate and faster version.
• gl.TRANSFORM_FEEDBACK_PRIMITIVES_WRITTEN: Number of primitives that are written to transform feedback buffers.

query

A WebGLQuery object for which to start the querying.

Return value

None.

Examples

var query = gl.createQuery();
gl.beginQuery(gl.ANY_SAMPLES_PASSED, query);

// ...

Specifications

Specification	Status	Comment
WebGL 2.0 The definition of 'beginQuery' in that specification.	Editor's Draft	Initial definition.
OpenGL ES 3.0 The definition of 'glBeginQuery' in that specification.	Standard	Man page of the (similar) OpenGL API.

Browser compatibility

See also

• WebGLQuery