TNT2 does not support the blend equation or constant color features in hardware, whereas GF does. You may have noticed, for example, that we support EXT_blend_color, EXT_blend_minmax, and EXT_blend_subtract on GF, but not on TNT2.
wglGetProcAddress itself has no impact on performance. However, the rendering state that you use does.
Hi! Thanks for that post, I had the same problem with glBlendColor. I tought my TNT2 supported glBlendColor, but it doesnt! Where can I find infos on what extensions are supported by some video card ?!?
There is a document on nvidia’s developer web site (probably under opengl sdk) called nvOpenGLSpecs.pdf. It has a big table of supported extensions on all their cards.
But that table can be a bit misleading if taken purely at face value, as it doesn’t always clearly state if a given extension is supported by hardware or if it is software only. A good example is the imaging ‘extension’ as listed on the table. The TNT is marked as supporting it, but it does not say that it is through software only.