Re: off axis projection pfMakePerscFrust
John Rohlf (jrohlf++at++tubes)
Thu, 5 Jan 95 14:26:35 PST
>
> I experience some problems with "pfMakePerscFrust". I use "pfMakePersFrust"
> to create off axis projection in my application which is based on SGI demo
> program "perfly". Part of the screen, in the direction toward where
> the line of sight is pointing at , was never refreshed correctly. There were
> two old images being displayed in this area alternately and the correct
> image was overlaid by these two wrong images. The image looked normal
> when symmetric (on axis) projection was used. The "pfMakePerscFrust" was
> called in the function "PreFrame". I tested the pfMakePerscFrust with the
> same arguments in the demo program "simple.c" and it looked just fine.
> Could any body give me a clue what might cause this problem?
My guess is that this is a problem in pfEarthSky
which does not yet properly handle off-axis frusta. Try simply
clearing the screen rather than drawing earthsky polygons.
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on Mon Aug 10 1998 - 17:50:49 PDT