It is not as old as I was thinking .... http://www.opengl.org/registry/specs/SUN/slice_accum.txt
$Date: 02/03/13 15:15:35 $Revision: 1.3 $ But extension itself talks about accumulation buffer(s)[0], they supported currently in software in mesa, and many old consumer-level cards seems don't have them implemented in hardware, unfortunately including old (pre-nv30) Nvidia cards, as far as i know ..... On nv30 and up accumulation buffer can be emulated, sort of. See [1], or [2] for 12-bit accumulation buffer. There was some interest in implementing accum. buffer in Mesa as metaop (?) or in mesa state tracker for Gallium drivers, but nothing come out, AFAIK. Sorry, can't find links right now [0] http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.91.4497&rep=rep1&type=pdf - "The Accumulation Buffer: Hardware Support for High-Quality Rendering" [1] http://www.petewarden.com/notes/archives/2005/05/fragment_progra.html [2] http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.14.9136&rep=rep1&type=pdf - "Complex Water Effects at Interactive Frame Rates" _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev