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WebGLRenderingContext.sampleCoverage

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

Syntax

void gl.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.

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	Status	Comment
WebGL 1.0 The definition of 'sampleCoverage' in that specification.	Recommendation	Initial definition.
OpenGL ES 2.0 The definition of 'glSampleCoverage' in that specification.	Standard	Man page of the OpenGL API.

Browser compatibilityUpdate compatibility data on GitHub

	Desktop
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari
Basic support	9	12	4	11	12	5.1

	Mobile
	Android webview	Chrome for Android	Edge Mobile	Firefox for Android	Opera for Android	iOS Safari	Samsung Internet
Basic support	Yes	25	Yes	Yes	12	8.1	Yes