View Full Version : gl_ClipVertex nvidia 8600

02-03-2008, 01:46 PM
I've been having problems getting user defined clip planes to work in my shaders. I've tested the same shader code on a macbook pro (intel based) with an ATI card, and windows and various flavors of linux and everything worked as expected. However, on my macbook pro (intel) with and nvidia 8600 card, user clip planes are ignored. Has anyone else seen something like this?

02-04-2008, 02:17 AM
You might want to read this thread which explains gl_ClipVertex implementation differences. That is, if you write to gl_ClipVertex the GeForce 8600 is supposed to work with the enabled user clip planes. If it doesn't that would be bug inside the Apple drivers. (I have no clue how to update graphics drivers on a Mac.)

http://www.opengl.org/discussion_boards/...true#Post232365 (http://www.opengl.org/discussion_boards/ubbthreads.php?ubb=showflat&Board=3&Number=232365&Searchpage=1&Main=46223&Words=clip&topic=0&Search=true#Post232365)

02-04-2008, 05:34 AM
Right. I've seen this and am actually setting gl_ClipVertex as described there in my vertex shader. I'm beginning to believe it is a driver bug. I wanted to test on a windows/linux box with 8 series graphics card before trying to go through the hoops of submitting a bug report to Apple...

02-21-2008, 08:39 AM
Well, I was able to reproduce this bug with one of the apple sample apps so I've submitted a bug...We'll see how long it takes to get a response...

Seth Hoffert
02-21-2008, 03:13 PM
I can confirm that user clip planes work fine with the 8800 cards in Linux, if this helps at all.

03-01-2008, 05:25 PM
I have previously see funny behavior under ATI hw, seemed like the driver was forced into software mode with gl_ClipVertex but that should have been corrected.

Perhaps you can write to the driver department at Apple, might be they could give you some info (they will properly like a simple down cut example of your problem though)

03-02-2008, 08:15 PM
I sent a bug through bugreporter.apple.com...Is that the correct channel to get to the driver dev team of Apple?

03-02-2008, 11:09 PM

Now you get to watch as your bug slides into an apparent black hole, and you're never informed of its progress, until one day, miraculously, it's marked as closed, and you're left to intuit what software version you should be testing against to verify the fix.

Ah, the fun.

03-03-2008, 06:19 AM
AWESOME! I take it I shouldn't hold my breath...