displa(3G)

NAME
     displa - specifies a displacement for the z values of rendered polygons

FORTRAN 77 SPECIFICATION
     subroutine displa(scalefactor)
     real*4 scalefactor

DESCRIPTION
     displa 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.  displa is
     effectively disabled by setting scalefactor to 0.0, which is the default.

     displa 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