Occlusion Culing extension with ATI driver and FEDORA 2

Hi,

I’m writing an occlusion culling program and there’s a weird problem with my ATI driver under Fedora 2. I have a Dell Inspiron 8600 with an ATI Radeon mobility 9600 card on it.

I installed the newest ATI driver (3.14.6) on my system - it works correct, well but not the best performance, only 1500fps in glxgears…but when I try to enable the occlusion culling extensions in my code, the program crashes. If I compile the same code at windows XP OS, everything works fine.

please contact me if you know more about this problem - I believe it’s a driver bug, but i’m not sure.

thanks

anselm grundhoefer

I haven’t heard any problems with occlusion culling in ATI’s drivers, but that doesn’t mean that there aren’t any. Which occlusion test extension are you using? There are three . :wink:

Can you be more specific about how the program crashes? Is it in your code? Is it in driver code? Can you provide a back trace? If you have a small glut or SDL based program that exhibits the problem, that would also help.

Finally, what does the app do with Mesa’s software rendering (other than run slowly :slight_smile: )?

thhank you for your reply.
you’re right - there are three. I use the ARB_OCCLUSION_QUERY extension.
I’m using the extenson in a QT software, but there is one small (GLUT) programm from Brian Paul I tried before and it didn’t work either.

I can’t say exactly where the program crashes, but I can send the queries, but when I wait for the result (glGetQueryObjectivARB(OccQuery, GL_QUERY_RESULT_AVAILABLE_ARB, &ready) :wink: I can wait until I die…

I don’t have any problems with the code when I’m using NVidia cards or Windows OS.

I will try it with the MESA gl and inform you.

thanks
a.grundhoefer

As far as I can remember the occlusion query demo in the nvidia sdk didn’t work correctly either with the ati drivers (but it did not crash).
A few driver versions seemed to return just a random count for the number of rendered fragments. I think the 3.14.6 (can’t test right now) always returns -1.

Actually it just hangs on my machine and the function will eventually never return.

It is working fine on all nvidia cards, plus I tested all 3 occlusion test extensions.

I’ve already filed a bug report to ATI, maybe they fix this issue for the next driver release (or maybe not…)

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