Multiple render passes causes artefacts on ATI

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11 comments, last by AIRmichael 20 years, 5 months ago
Hey, I have a problem with multiple render passes. I use glDepthFunc(GL_LEQUAL);. It seems that it works fine on NVidia cards, but on ATI cards artefacts can be seen. That means lines/dots nearby the camera that vanishes/popups while looking around. How can that be fixed? Greetings, Michael L. [edited by - AIRmichael on October 24, 2003 1:08:56 PM]
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Woooo dude, I think you have the syntax of the function wrong. glBlendFunc takes 2 paramateres for instance: glBlendFunc(GL_SRC_COLOR, GL_ONE). I''m not sure why yours even compiled. Try looking up the syntax in the MSDN library on microsoft''s site or whichever you use, but hey if one parameter works I''d be suprised.
Author Freeworld3Dhttp://www.freeworld3d.org
Sorry, glDepthFunc(GL_LEQUAL); it is. If it was blendfunc with 1 parameter it wouldnt even compile hehe.

[edited by - AIRmichael on October 24, 2003 1:10:13 PM]
how about depthfunc = GL_EQUAL?..



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This usually happen when your zNear is 0 or lower. you have to use at least a zNear of 0.1

Thx, didnt test it yet but I know what you mean and I think thats the problem as well.
ATI cards are known for their poor precision.

I hate them too :D
Known for their poor precision? I think you are very much mistaken. Both ATi and nVidia run at the same precisions (16/32 bit colour, 16/24 bit depth buffer), ATi has 24bit floating point math in fragment programs whilst nVidia has 16bit and 32bit (and is far slower).

I can do multipass rendering just fine on ATi cards, with better results than my previous nVidia card gave. What are your near and far clipping planes set to?
-----------------------"When I have a problem on an Nvidia, I assume that it is my fault. With anyone else's drivers, I assume it is their fault" - John Carmack
Just try to use the texture matrix and scroll x or y position by a large number.
Any value above 128 or below -128 should do, but try 10000 to be sure

You''ll get weird lines on an ATI, and magnification seems to fail - but no problem on my gf3.
Nope, renders exactly the same.

Whatever youre smoking.. I want some
-----------------------"When I have a problem on an Nvidia, I assume that it is my fault. With anyone else's drivers, I assume it is their fault" - John Carmack

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