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This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for usage in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the specification changes.
The WebGLQuery interface is part of the WebGL 2 API and provides ways to asynchronously query for information. By default, occlusion queries and primitive queries are available.
Another kind of queries are disjoint timer queries, which allow you to measure performance and profiling of your GPU. Disjoint timer queries are available with the EXT_disjoint_timer_query extension only.
When working with WebGLQuery objects, the following methods of the WebGL2RenderingContext are useful:
WebGL2RenderingContext.createQuery()WebGL2RenderingContext.deleteQuery()WebGL2RenderingContext.isQuery()WebGL2RenderingContext.beginQuery()WebGL2RenderingContext.endQuery()WebGL2RenderingContext.getQuery()WebGL2RenderingContext.getQueryParameter()
Examples
Creating a WebGLQuery object
in this example, gl must be a WebGL2RenderingContext. WebGLQuery objects are not available in WebGL 1.
var query = gl.createQuery();
Specifications
| Specification | Status | Comment |
|---|---|---|
| WebGL 2.0 The definition of 'WebGLQuery' in that specification. |
Editor's Draft | Initial definition. |
Browser compatibility
| Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari |
|---|---|---|---|---|---|
| Basic support | No support [2] | Nightly build [1] | No support | No support | No support |
| Feature | Android | Chrome for Android | Firefox Mobile (Gecko) | IE Mobile | Opera Mobile | Safari Mobile |
|---|---|---|---|---|---|---|
| Basic support | No support | No support | No support | No support | No support | No support |
[1] WebGL 2 is enabled by default in Firefox Nightly. To enable it in a release version of Firefox, set the preference webgl.enable-prototype-webgl2 to true in about:config.
[2] To use an experimental implementation of WebGL 2 in Chrome, you have to start Chrome with the runtime flag --enable-unsafe-es3-apis.