Web/API/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: 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 1.0The definition of 'polygonOffset' in that specification.	Recommendation	Initial definition.
OpenGL ES 2.0The definition of 'glPolygonOffset' in that specification.	Standard	Man page of the OpenGL API.

Browser compatibility

The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`polygonOffset`	Chrome Full support 9	Edge Full support 12	Firefox Full support 4	IE Full support 11	Opera Full support 12	Safari Full support 5.1	WebView Android Full support Yes	Chrome Android Full support 25	Firefox Android Full support Yes	Opera Android Full support 12	Safari iOS Full support 8	Samsung Internet Android Full support 1.5

Legend

Full support: Full support