Re: star z-buffer
Christopher Fouts (fouts++at++exacto.atlanta.sgi.com)
Thu, 13 Oct 1994 10:18:55 -0400
On Sep 29, 3:08pm, John C Vanderburgh wrote:
> Subject:
| Hey all,
| In my Performer application, I'm rendering some stars in a space
environment as point light sources.
| I use actual celestial coordinates converted to Earth-centered
rectangular
| coordinates, so my stars end up as a "celestial sphere" surrounding the
| Earth. This was working well until I discovered that if I move far
| enough in my world, objects that aren't within my "celestial sphere"
(such
| as the Sun or a distant planet, etc) will appear "behind" the stars. For
| various reasons, I don't want to increase the radius of my
| "celestial sphere" (in order to physically enclose all my objects).
| If I could somehow "clamp" the depth of the star pixels (in screen
| space) to the largest z-buffer value, it would
| seem that the stars would always appear "farther"
| than any other objects in my world. I read the man pages on
| "zbuffer", "zfunction", "zdraw", etc., but didn't find exactly what
| I was looking for. So, is there a way to alter the
| values used for z-buffer calculations for my stars? (or, for that
matter,
| any other suggestions on how to solve this dilemma?)
If you draw the stars before any other geometry, you can simply disable
z-buffering when drawing your stars.
--
Chris Fouts Email: fouts++at++atlanta.sgi.com
Systems Engineer Phone: (404)-392-1333
Silicon Graphics Computer Systems Vmail: 5-8714
Atlanta, GA
"I am not close-minded. End of discussion."
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