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GLPOLYGONOFFSET(3G) [FIXME: 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 × 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.

VERSION SUPPORT

OpenGL Version
Function / Feature Name 2.0 2.1 3.0 3.1 3.2 3.3 4.0 4.1 4.2 4.3 4.4 4.5
glPolygonOffset ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔

SEE ALSO

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

COPYRIGHT

Copyright © 1991-2006 Silicon Graphics, Inc. Copyright © 2010-2014 Khronos Group. This document is licensed under the SGI Free Software B License. For details, see http://oss.sgi.com/projects/FreeB/.

COPYRIGHT

Copyright © 1991-2006 Silicon Graphics, Inc.
Copyright © 2010-2014 Khronos Group

11/18/2024 [FIXME: source]