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Turbo_Pascal
02-20-2002, 07:42 AM
Hi,

I have writen severals Opengl programs, and all they work ultra fast and with not any problem in software opengl videocards.

But i always get reported that any of my opengl program run well on ATIs videocards.

Finally i was able to get a ATI radeo card, and yes, it' true, my opengl programs (and few from others autors) are not working mostly nothing is rendering in the screen.

I did some test in my code source and i found that dissabling the gl_depth_test flag make finally able to render the scene (but the perfomance is bad), of course I NEED THE Z TEST working!, but then the ATI will not works.

Searching on internet i found that the ATIs include a new technology called HIPER Z, which consist in a optomized Z depth test!! (so i guess that this is the problem) but i did not found any info anywhere telling about this incompatibility problem.

I can;t beleave that this is not happening to anyone else (???!!!) , how can make my opengl programs compatibles with hiperz using pure Opengl APIs?, i found some ATI opengl source codes but all them are writem using GLU and this is not good for me.

thank you,

tp.

nexusone
02-20-2002, 07:53 AM
I have a ATI Radeon card and have had good luck running openGL stuff on it.

You have a link to your demo? I could download it and give it a try on my system.


Originally posted by Turbo_Pascal:

Hi,

I have writen severals Opengl programs, and all they work ultra fast and with not any problem in software opengl videocards.

But i always get reported that any of my opengl program run well on ATIs videocards.

Finally i was able to get a ATI radeo card, and yes, it' true, my opengl programs (and few from others autors) are not working mostly nothing is rendering in the screen.

I did some test in my code source and i found that dissabling the gl_depth_test flag make finally able to render the scene (but the perfomance is bad), of course I NEED THE Z TEST working!, but then the ATI will not works.

Searching on internet i found that the ATIs include a new technology called HIPER Z, which consist in a optomized Z depth test!! (so i guess that this is the problem) but i did not found any info anywhere telling about this incompatibility problem.

I can;t beleave that this is not happening to anyone else (???!!!) , how can make my opengl programs compatibles with hiperz using pure Opengl APIs?, i found some ATI opengl source codes but all them are writem using GLU and this is not good for me.

thank you,

tp.

Furrage
02-20-2002, 11:01 AM
Have you tried changing options with glDepthFunc(...)? This might make a difference.

Majik
02-20-2002, 01:02 PM
I run an ATI Mobility 4 on my laptop, and I've found hardware OpenGL performance pretty good.

Turbo_Pascal
02-20-2002, 03:00 PM
Originally posted by Furrage:
Have you tried changing options with glDepthFunc(...)? This might make a difference.

yeap, i did,

if i enable the gl_depth_test with and the gldepthfunc with value Gl_greater or gl_always then the model is render, but the z test is not working well, the polygons that are behind other polygons are render as if the front polygons are transparent.

Seems that this is a bug in the so called HIPPER Z feature included in ATIs, where supost mean this is a optimized and faster z depth test. arrrrggg..

tp.

baloneyman
02-20-2002, 03:05 PM
Small world. Never noticed you've been
here before.

Yeah, probs with ATI cards, (ouch).

I cannot give you a definite answer but:

Some Mac programmer said don't set the
near Z closer than 1.0 (I usually use 0.1)
and don't set the far Z greater than 10,000.

I was under the impression that ATI's
'fast Z clear' was the problem but never
could confirm it (no user of TRitem wanted
to help, you know how that goes!) But I'm
pretty sure ATI would handle something like
that in their driver.

Am also emailing you a bit of info on
some Registry settings that can disable
a lot of ATI's special Z enhancements.
Perhaps you can test it out.

You da' man, Turbo

Roy...

iNsaNEiVaN
02-20-2002, 06:41 PM
I have been using a voodoo3 for 2 years and it has been working fine on all the progs ive been writing. A couple days ago I went out and bought a cheap radeon. For some reason it performed terribly on all my opengl progs. More than two times slower than my voodoo3. Strange.