https://bugs.freedesktop.org/show_bug.cgi?id=83510
--- Comment #13 from Michel Dänzer michel@daenzer.net --- (In reply to Clément Guérin from comment #12)
Low lighting glitch is still here. "can be seen in the Realistic Rendering demo or the Shooter Game demo with the Sanctuary map"
Make sure you use the current versions of the demos. I was seeing the darkness in the first version of the Realistic Rendering demo, but it's fixed with the current version, and Shooter Game looks fine as well.