Hi guys, This is a vague bug report at best - hence mentioned here in case it means anything to anyone. I've not really got enough to file anything useful in Bugzilla yet!
I've been working on GL code for a PCB design app. It uses various bits in the stencil buffer for sub-compositing. To avoid expensive clear operations, it uses each of the bits on the stencil buffer independently (in turn), only clearing the buffer when it runs out of pre-cleared bits. I'm using two drawing windows (and two GL contexts), set up with GtkGlExt. With the latest mesa code (sorry - no idea when it regressed), calling glClear (GL_STENCIL_BUFFER_BIT); on my second drawing context seems to corrupt the main drawing context, preventing its colour buffer being properly cleared when it is next used. Since I'd expect the two contexts to be separate, and not affect each other - I can only assume that the driver is somehow muddling them up with regards to the stencil buffer. Removing the glClear (GL_STENCIL_BUFFER_BIT); on my second context, both windows render "properly". (The second context doesn't _really_ need the sub-compositing, so I can get away with that for now). I'm using mesa from the Ubuntu Xorg-edgers PPA: 7.7.0~git20090928.d492e7b0-0ubuntu0 Along with the intel driver: 2:2.8.99.902~git20090923.a92bbcc9-0ubuntu0tormod Forcing software rendering fixes the issue - and I know this same code has worked properly with older mesa versions (with HW acceleration). Any ideas? Unfortunately I've not got a lot of time at the moment to distil a succinct test-case. Regards, -- Peter Clifton Electrical Engineering Division, Engineering Department, University of Cambridge, 9, JJ Thomson Avenue, Cambridge CB3 0FA Tel: +44 (0)7729 980173 - (No signal in the lab!) ------------------------------------------------------------------------------ Come build with us! The BlackBerry® Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9-12, 2009. Register now! http://p.sf.net/sfu/devconf _______________________________________________ Mesa3d-dev mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/mesa3d-dev
