https://bugs.freedesktop.org/show_bug.cgi?id=34206
--- Comment #6 from Pavel Ondračka pavel.ondracka@email.cz 2011-02-12 11:26:59 PST --- The distorted glow is present since "r300/compiler: use peephole and constant folding for vertex shaders too", there was no glow at all before. So I suppose this explains why there is no glow with noopt.