Here is a quick guide:
- you need the 2.6.30 or later kernel (or else Occlusion Query will be disabled).
Ubuntu 9.04 users: download (just the linux-image-* for your architecture), install (with sudo dpkg -i) and boot the latest 2.6.30.x kernel from: http://kernel.ubuntu.com/~kernel-ppa/mainline/?C=M;O=D
- make sure you have the development environment to build mesa. Ubuntu 9.04 users:Code:sudo apt-get build-dep mesa; sudo apt-get install git-core
Code:cd ~ git clone git://anongit.freedesktop.org/mesa/mesa cd mesa ./autogen.sh --disable-gallium --with-dri-drivers="swrast,r300" make export LIBGL_DRIVERS_DIR=~/mesa/lib
Test on a RV530 (313MHz GPU - 300 MHz memory) with an Intel Core Duo T2600 @ 2.16Ghz:
- arbocclude demo from mesa-osiris/progs/demos works fine;
- sauerbraten also works fine but it's slower (with OQ disabled ~85fps, with OQ enabled ~79fps).
As discussed on IRC performance improvement is related to CPU and GPU clock ratio. Downclocking my CPU to 1GHz with sauerbraten gives the OQ version better performance (~65 fps) than without OQ (~47fps), at least with sauerbraten and when not using KMS. OQ improves performance only with a "fast" GPU and a "slow" CPU.
Occlusion query support was merged in mesa master in 2009-08-15 and will be included in mesa 7.6.