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


void gl.sampleCoverage(value, invert);


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

Return value



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.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


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 compatibility

Feature Chrome Edge Firefox Internet Explorer Opera Safari Servo
Basic Support9124.011125.1No support
Feature Android Chrome for Android Edge Mobile Firefox for Android IE Mobile Opera Mobile Safari Mobile
Basic Support(Yes)25(Yes)4.011128.1

See also

Document Tags and Contributors

 Contributors to this page: teoli, fscholz
 Last updated by: teoli,