I’ve been using GL_CLAMP_TO_BORDER recently. On some of the PCs I’ve been working on, using GL_CLAMP_TO_BORDER is much slower than GL_CLAMP_TO_EDGE. I have thought that this might be due to a lack of hardware support. Is there any source that I can look to for finding out which of the available (and soon to be available) graphics cards support GL_CLAMP_TO_BORDER?
GeForce2 doesn’t support borders at all in hardware, except possibly for the case of a single border color. Thus, it would stand to reason that CLAMP_TO_BORDER isn’t accelerated. By the way: unless you turn on specific conformant behavior, GL_CLAMP means CLAMP_TO_EDGE for GF2 cards.