Indigo XS24 Sphere library z-buffering problems

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3 total messages Started by SML108 Mon, 14 Dec 1992 19:16

#41

Author: SML108
Date: Mon, 14 Dec 1992 19:16

13 lines
1054 bytes

Hi, a program I am developing which uses the sphere library runs just
fine on an IRIS 4D/220 VGS, but when I run it on a nearby Indigo XS24,
the SPH_HEMI seems to get set true by default with SPH_ORIENT set to
FALSE (It draws hemispheres which show up as you rotate objects on
the screen).  If I set SPH_HEMI and SPH_ORIENT to TRUE, this problem
goes away, but then z-buffering goes away too and the appearance of
spheres on the screen is as if they all have the same z-coordinate
and appear in the order in which they are drawn...  The Indigo is
running 4.0.5 and zbuffer is most definitely set to TRUE...

Oh, one more thing, this is in a GLX widget that this is happening...

Scott Le Grand

Re: Indigo XS24 Sphere library z-buffering problems

#47

Author: Arthur Evans
Date: Tue, 15 Dec 1992 02:58

27 lines
1763 bytes

In article <92349.141625SML108@psuvm.psu.edu> SML108@psuvm.psu.edu writes:
>Hi, a program I am developing which uses the sphere library runs just
>fine on an IRIS 4D/220 VGS, but when I run it on a nearby Indigo XS24,
>the SPH_HEMI seems to get set true by default with SPH_ORIENT set to
>FALSE (It draws hemispheres which show up as you rotate objects on
>the screen).  If I set SPH_HEMI and SPH_ORIENT to TRUE, this problem
>goes away, but then z-buffering goes away too and the appearance of
>spheres on the screen is as if they all have the same z-coordinate
>and appear in the order in which they are drawn...  The Indigo is
>running 4.0.5 and zbuffer is most definitely set to TRUE...

Are you sure you have zbuffers?  Zbuffer hardware is an extra
cost option with XS24 graphics, and unlike Entry graphics XS24
doesn't do software zbuffering.

If you don't know whether you have zbuffer hardware, try running
/usr/gfx/gfxinfo.  Output on a XS24z (XS with zbuffer hardware)
should look something like this:

	Graphics board 0 is "GR2" graphics.
        	Managed (":0.0") 1280x1024 
        	1 GE, 24 bitplanes, 4 auxplanes, 4 cidplanes, Z-buffer
							      ^^^^^^^^
If you do have the zbuffer hardware, spheres should draw correctly
with SPH_HEMI and SPH_ORIENT set to TRUE.
 
arthur

Re: Indigo XS24 Sphere library z-buffering problems

#49

Author: SML108
Date: Tue, 15 Dec 1992 15:25

15 lines
980 bytes

In article <tk21c0o@zola.esd.sgi.com>, arthur@sgi.com (Arthur Evans) says:
>
>
>Are you sure you have zbuffers?  Zbuffer hardware is an extra
>cost option with XS24 graphics, and unlike Entry graphics XS24
>doesn't do software zbuffering.

That's the problem...  I was going by the graphics programming manual's
statement about software z-buffering...

So given that I do not have z-buffering on this machine, how does it run
programs like flight and battlezone without screwing up the graphics?
Do they just sort objects by depth before they are drawn?

Scott

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