I have an OpenGL based 3D viewing program. It's having a rendering problem
related to the
NVIDIA GeoForce video cards. The problem is persistent on different versions
of the display driver.

First, the problem happens only when the light model is set as two sided
with the call:

 glLightModeli(GL_LIGHT_MODEL_TWO_SIDE, 1);

When the 3D object was rendered and rotated, sometimes I got a partial
rendering (only a part
of the object is visible).

Also, the problem happens only the first time the program was started after
the PC was booted up. After
I quit the program and restart the program again, the problem seems to be
gone and rendering is OK.

I suspect NVIDIA might require some initialization or something as the same
program works fine
on other machines with ATI cards.

Any idea about the problem and possible solutions?

Thanks

Ted

"Ted Wu" <ytedwu@gmail.com> wrote in message 
news:d%Dah.10140$d42.10021@trndny07...
>I have an OpenGL based 3D viewing program. It's having a rendering problem
> related to the
> NVIDIA GeoForce video cards. The problem is persistent on different 
> versions
> of the display driver.
>
> First, the problem happens only when the light model is set as two sided
> with the call:
>
> glLightModeli(GL_LIGHT_MODEL_TWO_SIDE, 1);
>
> When the 3D object was rendered and rotated, sometimes I got a partial
> rendering (only a part
> of the object is visible).
>
> Also, the problem happens only the first time the program was started 
> after
> the PC was booted up. After
> I quit the program and restart the program again, the problem seems to be
> gone and rendering is OK.
>
> I suspect NVIDIA might require some initialization or something as the 
> same
> program works fine
> on other machines with ATI cards.
>
> Any idea about the problem and possible solutions?
>
> Thanks
>
> Ted
>
>
>

Sounds like a defective card. Are you checking for errors? Do you have 
backface culling turned on ?
jbw

"jbwest" <jbwest@comcast.net> wrote in message
news:fvOdnbVtxOBj9_HYnZ2dnUVZ_vudnZ2d@comcast.com...
>
>
> Sounds like a defective card. Are you checking for errors? Do you have
> backface culling turned on ?
> jbw
>
>

The problem only happens when the program starts after the system was just
booted up. After using the program
a little bit, I'd get a "Microsoft C++ Runtime Library run time error"
message. The program quits. After that,
the problem will never happen until the system is rebooted and the above
repeat once.

Could not find any errors, no memory leak or anything. Any ideas?