1991-2006 Silicon Graphics, Inc. glPolygonOffset 3G glPolygonOffset set the scale and units used to calculate depth values void glPolygonOffset GLfloat factor GLfloat units 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. 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 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. glIsEnabled with argument GL_POLYGON_OFFSET_FILL, GL_POLYGON_OFFSET_LINE, or GL_POLYGON_OFFSET_POINT. glGet with argument GL_POLYGON_OFFSET_FACTOR or GL_POLYGON_OFFSET_UNITS. glDepthFunc, glEnable, glGet, glIsEnabled Copyright 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see http://oss.sgi.com/projects/FreeB/.