Gl.PolygonOffset (gb.opengl)

Set the scale and units used to calculate depth values.

Parameters

factor

Specifies a scale factor that is used to create a variable depth offset for each polygon. The initial value is 0.

units

Is multiplied by an implementation-specific value to create a constant depth offset. The initial value is 0.

Description

When Gl.POLYGON_OFFSET_FILL, Gl.POLYGON_OFFSET_LINE, or Gl.POLYGON_OFFSET_POINT is enabled, each fragment's depth value will be offset after it is interpolated from the depth values of the appropriate vertices. The value of the offset is $\mathit{factor}\times \mathit{DZ}+\mathit{r}\times \mathit{units}$, where $\mathit{DZ}$ is a measurement of the change in depth relative to the screen area of the polygon, and $\mathit{r}$ is the smallest value that is guaranteed to produce a resolvable offset for a given implementation. The offset is added before the depth test is performed and before the value is written into the depth buffer.

Gl.PolygonOffset is useful for rendering hidden-line images, for applying decals to surfaces, and for rendering solids with highlighted edges.

Associated Gets

Gl.IsEnabled with argument Gl.POLYGON_OFFSET_FILL, Gl.POLYGON_OFFSET_LINE, or Gl.POLYGON_OFFSET_POINT.

Gl.Get with argument Gl.POLYGON_OFFSET_FACTOR or Gl.POLYGON_OFFSET_UNITS.

See also

See original documentation on OpenGL website