Re: Shadow bug
Angus Dorbie (dorbie++at++sgi.com)
Wed, 13 May 1998 13:49:03 -0700
Kenneth B Russell wrote:
>
> > The self shadow theory seems unlikely, particularly since only parts
> > seem to be occulted and you tried different offsets.
> >
> > Maybe there is some interaction with pfLayers (stencil or polygon
> > offset)
> > or other state information and the shadow rendering?
> >
> > One thing to try is to disable antialiasing and see if the problem
> > persists, this might point an accusatory finger ad zbuffer compression
> > on iR.
>
> We don't do anything fancy in our application yet; no stencil
> planes, no antialiasing, and no manual use of the polygon offset
> extension.
>
> The problem is concisely shown in this example from the Performer
> 2.2 MR.
>
> If you compile /usr/share/Performer/shadows.c from
> /usr/share/Performer/src/pguide/libpf/C with the following
> command line:
>
> cc -o shadows shadows.c -lpf -lpfdu -lpfutil -lGL -lGLU -lX11 -limage
>
> (we're using the 7.1 compilers patched up to #2072, on an Onyx2
> iR running Irix 6.4), and then run the executable by
>
> shadows stool.flt
>
> (where stool.flt is in /usr/share/Performer/data), then there
> will be two "blips" as the shadowed light does its orbit; the
> shadow suddenly turns into a big black box for a moment. Those
> blips look exactly like what I'm seeing in my application.
>
> We have a support contract; should I be reporting this problem in
> some other venue than here?
Yes. For call tracking etc you should log a call with your local
customer support.
Cheers,Angus.
--
"Only the mediocre are always at their best." -- Jean Giraudoux
For advanced 3D graphics Performer + OpenGL based examples and tutors:
http://www.dorbie.com/
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on Mon Aug 10 1998 - 17:57:24 PDT