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Re: Sementation fault in OpenGL application


Actually I'm thinking that the problem is not with the video driver. I renamed the driver dll so that the system would use the software renderer instead of the video card driver. The same problem occurred in a call to wglChoosePixelFormat provided by the software render.

I checked the documentation for DrvSetPixelFormat on the Microsoft website. It mentioned that this call should only be made once and calling it multiple times can cause problems with the window manager and the multithreaded applications. I would think that this function has already been called earlier in the program when I actually specify my pixel format while initializing OpenGL with calls to the ChoosePixelFormat and SetPixelFormat API's.

After this initialization, I then try to create a texture, and that is where the problem is occuring. I'm not sure why this DrvSetPixelFormat is being called while making the texture. It seems that this method might be called when it shouldn't be, and that could be related to the problem.

lhall at pop dot ma dot ultranet dot com wrote:

Unless someone here has the same video card, driver (+version), and
can reproduce your problem, I'm not sure you'll get much response here beyond the advice already given. Certainly it is possible that
there is a video driver issue and that would certainly be specific to
the card in question. But it's also possible that your program is causing a problem for the video driver. It's also possible that there's
a bug elsewhere (i.e. gcc) which is contributing to this failure. But
the answer to where the problem actually lies will come from some analysis.
Then again, there might be someone here on the list that has seen exactly
this problem and will pipe up with a solution. It's my impression that if
that was the case, you would've heard from that person already. So I'm
recommending you don't hold your breath waiting for that nice, simple solution to come your way. ;-)


Larry

Original Message:
-----------------
From: Tron Thomas tron dot thomas at verizon dot net
Date: Sun, 23 Mar 2003 16:31:07 -0800
To: cygwin at cygwin dot com
Subject: Sementation fault in OpenGL application


Earlier I had posted a message concerning I segmentation fault I get when I build an OpenGL application using the GCC compiler on Cygwin. I have since discovered that the debugger spits out some information when the segmentation fault occurs. The is what it says:


Program received signal SIGSEGV, Segmentation fault.
0x6966190c in nvoglnt!DrvSetPixelFormat ()

I have a 64 Megabyte nVidia GeForce 3 video card on my system. The debug message implies the error is occuring in the video driver. I do not know what would be causing this, especially when the program runs fine when built with other compilers.

Can anyone offer any help on this matter?



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