WebGLRenderingContext: sampleCoverage() method

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

See full compatibility

Note: This feature is available in Web Workers.

The WebGLRenderingContext.sampleCoverage() method of the WebGL API specifies multi-sample coverage parameters for anti-aliasing effects.

Syntax

sampleCoverage(value, invert)

Parameters

value: A GLclampf which sets a single floating-point coverage value clamped to the range [0,1]. The default value is 1.0.
invert: A GLboolean which sets whether or not the coverage masks should be inverted. The default value is false.

Return value

None (undefined).

Examples

Multi-sampling is disabled by default. To enable or disable multi-sampling, use the enable() and disable() methods with the argument gl.SAMPLE_COVERAGE and gl.SAMPLE_ALPHA_TO_COVERAGE.

gl.enable(gl.SAMPLE_COVERAGE);
gl.sampleCoverage(0.5, false);

To check the sample coverage values, query the SAMPLE_COVERAGE_VALUE and SAMPLE_COVERAGE_INVERT constants.

gl.getParameter(gl.SAMPLE_COVERAGE_VALUE); // 0.5
gl.getParameter(gl.SAMPLE_COVERAGE_INVERT); // false

Specifications

Specification
WebGL Specification # 5.14.3

Browser compatibility

	desktop					mobile
	Chrome	Edge	Firefox	Opera	Safari	Chrome Android	Firefox for Android	Opera Android	Safari on iOS	Samsung Internet	WebView Android	WebView on iOS
`sampleCoverage`	Chrome – Full support Chrome 9 (Release date: 2011-02-03) footnote Full support	Edge – Full support Edge 12 (Release date: 2015-07-29) footnote Full support	Firefox – Full support Firefox 4 (Release date: 2011-03-22) footnote Full support	Opera – Full support Opera 12 (Release date: 2012-06-14) footnote Full support	Safari – Full support Safari 5.1 (Release date: 2011-07-20) footnote Full support	Chrome Android – Full support Chrome Android 25 (Release date: 2013-02-27) footnote Full support	Firefox for Android – Full support Firefox for Android 4 (Release date: 2011-03-29) footnote Full support	Opera Android – Full support Opera Android 12 (Release date: 2012-02-25) footnote Full support	Safari on iOS – Full support Safari on iOS 8 (Release date: 2014-09-17) footnote Full support	Samsung Internet – Full support Samsung Internet 1.5 (Release date: 2013-09-25) footnote Full support	WebView Android – Full support WebView Android 4.4.3 (Release date: 2014-06-02) footnote Full support	WebView on iOS – Full support WebView on iOS 8 (Release date: 2014-09-17) footnote Full support

Tip: you can click/tap on a cell for more information.

Full support: Full support