Method GL.glPolygonOffset()

Method glPolygonOffset

void glPolygonOffset(float factor, float units)

Description

When GL_POLYGON_OFFSET 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 "factor" ~*~ DZ ~~+~~ r ~*~ "units", where DZ~ is a measurement of the change in depth relative to the screen area of the polygon, and 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.

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

Parameter factor

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

Parameter units

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

Throws

GL_INVALID_OPERATION is generated if glPolygonOffset is executed between the execution of glBegin and the corresponding execution of glEnd.