GLPOLYGONOFFSET(3G) OpenGL Manual GLPOLYGONOFFSET(3G)
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 x DZ + r x 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 (C) 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
opengl.org 06/10/2014 GLPOLYGONOFFSET(3G)
