That’s in a fragment shader, right?
Sounds like the chip on that board doesn’t support gl_FrontFacing.
In that case here’s a trick for a workaround by “abusing” a normally unused color varying.
Sounds like the chip on that board doesn’t support gl_FrontFacing
That is the first thing that crossed my mind but its a pretty new Nvidia card and its a pretty odd error for a call thats not supported… so I thought I would ask.
>>but its a pretty new Nvidia card<<
Not really. According to this document it’s still based on the previous chip generation. http://developer.nvidia.com/object/nv_ogl2_support.html
The workaround is mentioned in there as well.
The built-in fragment shader varying parameter gl_FrontFacing is supported by
GeForce 6 Series and NV4xGL-based Quadro FX GPUs but not GeForce FX and
NV3xGL-based Quadro FX GPUs.
and the 3000 is indeed a NV3xGL-based Quadro card. Thanks.
Why doesn’t it just pick up the two sided lighting model parameter as specified by:-
glLightModeli(GL_LIGHT_MODEL_TWO_SIDE, 1);
???
Why a new state token?
That’s not “new”, it’s six years old. I don’t know why the vertex_program specs haven’t reused the light model state either.
I think it really only enables the back color routing from vertex to fragment shader.