you can find plenty of code in Roassal3d that I think uses the NBOpenGL library here
NBOpenGL is basically a wrapper for OpenGL with Nativeboost. So if you are familiar with OpenGL , C and Nativeboost you are good to go using Roassal3d as an example to help you figure things out.��
I tried to make a set of tutorial but OpenGL proven very hard to tame. My main problem with my previous iMac was that Apple did not give error reporting for OpenGL which made it close to impossible to figure what went wrong with my OpenGL code. I have not tried to see if the situation improved with my new iMac that I purchased in the beginning of this year.��
Please note that previous iMac was 7 years old and still using Lion.��
Another tool that uses NBOpenGL is codecity. Bare in mind that OpenGL is pure graphics operation for the GPU so it does not provide with file loaders etc but I am sure using the tools I told you about you will fill in the gaps.