WebGLRenderingContext: polygonOffset() method

{{APIRef("WebGL")}}{{AvailableInWorkers}}

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

polygonOffset(factor, units)

Parameters

• factor
  • : A {{domxref("WebGL_API/Types", "GLfloat")}} which sets the scale factor for the variable depth offset for each polygon. The default value is 0.
• units
  • : A {{domxref("WebGL_API/Types", "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 ({{jsxref("undefined")}}).

Examples

The polygon offset fill is disabled by default. To enable or disable polygon offset fill, use the {{domxref("WebGLRenderingContext.enable", "enable()")}} and {{domxref("WebGLRenderingContext.disable", "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

{{Specifications}}

Browser compatibility

{{Compat}}

See also

• {{domxref("WebGLRenderingContext.depthFunc()")}}