As far as I can tell, it's as if every GL request to draw a polygon has been shifted by one point: so if it was trying to draw ABCD, it is instead drawing BCDE. This happens for every GL program. Why? How? Who knows. Maybe if I reboot, it will go away. I haven't seen this particular insanity before. I've seen shading randomly stop working on scenes that have a second light source; I've seen the back buffer vanish; I've seen DRI turn itself off; I've seen attack ships on fire... no wait, that wasn't me. It does this kind of thing totally at random. I've even had the video card (a G450) get into failure modes where the only way to un-fuck it has been to power the machine down: rebooting was insufficient. Happy happy joy joy.