(In reply to Marek Olšák from comment #8)
> (In reply to Christoph Haag from comment #7)
> > I think in the new "Lightroom Interior" the blackness glitch is visible in a
> > more interesting way:
> > https://www.youtube.com/watch?v=R9N-srsF_Fg
> 
> I think I've tracked down what's causing the blackness in all Unreal Engine
> demos: Division by zero.
> 
I didn't debug this of course, but it seems suspicious that this would depend
on division be zero returning zero instead of infinity. I don't think any other
driver for current hardware does that with GLSL. Are you sure there's not a
subsequent multiplication by zero that depends on INF * 0 returning 0 instead
of NAN?