The WebGLRenderingContext.polygonOffset()
method of the WebGL API specifies the scale factors and units to calculate depth values.
The offset is added before the depth test is performed and before the value is written into the depth buffer.
Syntax
void gl.polygonOffset(factor, units);
Parameters
- factor
- A
GLfloat
which sets the scale factor for the variable depth offset for each polygon. The default value is 0. - units
- A
GLfloat
which sets the multiplier by which an implementation-specific value is multiplied with to create a constant depth offset. The default value is 0.
Return value
None.
Examples
The polygon offset fill is disabled by default. To enable or disable polygon offset fill, use the enable()
and disable()
methods with the argument gl.POLYGON_OFFSET_FILL
.
gl.enable(gl.POLYGON_OFFSET_FILL); gl.polygonOffset(2, 3);
To check the current polygon offset factor or units, query the POLYGON_OFFSET_FACTOR
and POLYGON_OFFSET_UNITS
constants.
gl.getParameter(gl.POLYGON_OFFSET_FACTOR); // 2 gl.getParameter(gl.POLYGON_OFFSET_UNITS); // 3
Specifications
Specification | Status | Comment |
---|---|---|
WebGL 1.0 The definition of 'polygonOffset' in that specification. |
Recommendation | Initial definition. |
OpenGL ES 2.0 The definition of 'glPolygonOffset' 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 |