How much VRAM for textures/buffers?

[Fenris]

Am I correct assuming that the amount of texture memory available resident on the video board is the VRAM size minus the memory required for video buffers, right?

A GF2MX32MB would probably have about 28 MB left for textures, under a 800x600 double-buffered color-only context, or am I way too optimistic? :)

[Sohta]

Originally posted by Fenris
Am I correct assuming that the amount of texture memory available resident on the video board is the VRAM size minus the memory required for video buffers, right?


The answer would be yes and no.
The short answer is yes. The openGL info window in the openGL driver monitor will confirm that (actually it claims that you have even more texture memory than that, I get about 30 Megs of texture memory on a 1024x768 display) with a 32 Mb card.

The problem is, textures are not the only things that can get cached in the "texture" memory. Some OpenGL implementations (IIRC the Red book) can cache display lists directly on the video card for example. The same thing goes for offscreen buffers, depth buffers stencil buffers etc. I don't really know wich of those get cached on the video card (i'm pretty sure that it's implementation specific though). Also, there are NVidia extensions to write memory directly in that space (to stock vertex arrays for example). So while you do have all that memory available for textures, it could get clogged up by other stuff too.

hope it helps

[Fenris]

Exactly what I wanted to hear. :) Thanks!