displacepolygon(3G) displacepolygon(3G)
NAME
displacepolygon - specifies a displacement for the z values of rendered
polygons
C SPECIFICATION
void displacepolygon(float scalefactor)
DESCRIPTION
displacepolygon offsets the z values of rendered pixels for polygons.
The term scalefactor*max(abs(dz/dx),abs(dz/dy)) is added to the z values
of rendered pixels, where dz/dx and dz/dy are the slopes of the triangle
in window coordinates. scalefactor is a signed float value.
displacepolygon is effectively disabled by setting scalefactor to 0.0,
which is the default.
displacepolygon is recommended when rendering a z buffer that is later
defined (see texdef) as a texture for generating shadows. It can also be
used to offset polygons so that lines drawn around their borders do not
intersect them. This technique can be used to support hidden line
drawing and outlined facets.
NOTES
IRIS-4D G, GT, GTX, VGX, and VGXT models and the Personal Iris do not
support this function.
SEE ALSO
texdef
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