WebGLRenderingContext.polygonOffset()

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
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

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidEdge MobileFirefox for AndroidOpera for AndroidiOS SafariSamsung Internet
Basic supportChrome Full support 9Edge Full support 12Firefox Full support 4IE Full support 11Opera Full support 12Safari Full support 5.1WebView Android Full support YesChrome Android Full support 25Edge Mobile Full support YesFirefox Android Full support YesOpera Android Full support 12Safari iOS Full support 8.1Samsung Internet Android Full support Yes

Legend

Full support  
Full support

See also

Document Tags and Contributors

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