I want to know how to determine if there is sufficient texture memory to perform volume rendering using 3D texture (EXT_texture3D with a geForce4 card). The symptom is that when there is insufficient memory the volume is solid white; however, if I resize the volume so that it is smaller then it will display properly. The function glGetError and proxy calls were not helpful (error reporting in general seems incidental, but maybe I am missing something). I also had a problem with my BIOS configuration for AGP memory following my upgrade from geForce3 to geForce4. The geForce4 has 128MB of memory; however, my BIOS was only configured for 64MB (for the geForce3). This problem was traced using a program from nVidia (for which I have no source) that displayed the amount of AGP memory configured and available.

I am interested in a solution that will provide some guidance to users. Furthermore, it is possible for the application/process to have other OpenGL usage requiring memory such as texture, p-buffer, stencil-buffer etc.