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
GLclampfwhich sets a single floating-point coverage value clamped to the range [0,1]. The default value is 1.0. - invert
- A
GLbooleanwhich sets whether or not the coverage masks should be inverted. The default value isfalse.
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 compatibility
| Feature | Chrome | Edge | Firefox (Gecko) | Internet Explorer | Opera | Safari |
|---|---|---|---|---|---|---|
| Basic support | 9 | 12 | 4.0 (2.0) | 11 | 12 | 5.1 |
| Feature | Android | Chrome for Android | Edge | Firefox Mobile (Gecko) | Firefox OS | IE Mobile | Opera Mobile | Safari Mobile |
|---|---|---|---|---|---|---|---|---|
| Basic support | ? | 25 | (Yes) | 4.0 (2.0) | 1.0 | ? | 12 | 8.0 |
See also
HTMLCanvasElement.getContext()–antialiasparameter for the context.