NAME

       glPolygonOffset - set the scale and units used to calculate depth values

C SPECIFICATION

       void glPolygonOffset(GLfloat factor, GLfloat units);

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 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.

ASSOCIATED GETS

       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.

SEE ALSO

       glDepthFunc(), glEnable(), glGet(), glIsEnabled()

COPYRIGHT

       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/.

AUTHORS

       opengl.org