Is it possible from OpenGL to find out how much “high performance memory” (I mean memory for textures) is available and how much is being used just now?

No. It’s impossible.

you can use texture proxys to tell if a certain texture will fit in texture memory at a certain time. you might be able to use this to figure out roughly how much memory is available for storing textures, but it probably wont be very accurate, and it will also be slow, so you probably should only do it durring initialization or debugging, not durring drawing…

Thanks for your reply.

If it is not possible directly from OpenGL, is there ANY way how to find out? (I mean I have heard the DirectX can do that, but is there a way that avoids using DirectX)?

thanks in advance

well, you could try add one byte to the proxy texture and loading it untill it wont fit, then thats how much it will hold

of course, that doesnt take into account having vertex data in the memory, but it should tell you how much memory there is.

anything else is probably os specific, i dont know of any os specific stuff that will tell you this, but if you say what os you are using, someone else might…