Hansong Zhang (zhangh++at++cs.unc.edu)
Tue, 14 May 1996 11:37:56 -0400 (EDT)
I have several questions about using pfLightSource for projective
textures:
(1) The GL demo program, projtex, uses 4 passes in producing spotlight
effect while pfLightSource uses at most 2. (In pfLightSource man
pages, "extra draw pass(es)" for PROJTEX is 0-1.) So what passes
does performer projective texture omit and why? Does it use
similiar techniques as the GL program?
(2) The pfLightSource man pages say that on RE, "... projected
textures are not clipped or properly computed behind the
pfLightSource...". In the GL projtex demo, TX_SELECT is used to
kill pixels outside the 0 to 1 range of the texture projection,
and it doesn't seem to have difficulty with geometry behind the
projector. (when I point the projector away from one of the
walls, the wall is still rendered O.K.) So why does performer
has this limitation?
Thanks and have a nice day,
Hansong
- -- - -- - -- - -- - -- - -- - -- - -- - -- - -- - -- - -- -
Hansong Zhang zhangh++at++www.cs.unc.edu
Walkthrough Group http://www.cs.unc.edu/~zhangh
Department of Computer Science (919)962-1835 (O)
UNC-Chapel Hill (919)914-3973 (H)
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