49b725a1b2
Correct math requires the ambient component of the lightgrid to be zero in that case. However, q3 ignores lightgrid cells with all zero ambient value, EVEN if the directed value is nonzero. This change sets the ambient value to #010101 if it'd be pitch black. This should be a minimal change without affecting light hue that fixes lightgrid rendering. In engines like DarkPlaces, almost no map should look different from this. Fixes https://gitlab.com/xonotic/netradiant/-/issues/137