I'm using the OpenGL accumulation buffer to perform antialiasing with arbitrary filters. On an ATI Mobility Radeon X300 (as well as X1000 and HD3000 series) my application doesn't seem to get an accumulation buffer although when I list all available pixelformats there are some which support for the accumulation buffer. I'm using Qt for the GL widget and I'm requesting a double-buffer, depth, rgba and accumulation buffer. I have found a similar thread (http://forums.amd.com/game/messageview.cfm?catid=260&threadid=123808) in the games forums, but unfortunately no answer was given. Are there others that have made the same experience?