- Method glPolygonOffset
void glPolygonOffset(float factor, float units)
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.