Thanks guys.
I dont think its an exploit its just the maths of the light, if you know what I mean. I imagine all DX is doing is adding the light value and with it been negative, it just takes light away.
It also holds true if you give your objects a negative color, they get brighter again.
Some more experiments:
The effect only seems to work well with smooth objects but then Mustangs "bug" would come in useful.
I dont think its an exploit its just the maths of the light, if you know what I mean. I imagine all DX is doing is adding the light value and with it been negative, it just takes light away.
It also holds true if you give your objects a negative color, they get brighter again.
Some more experiments:
The effect only seems to work well with smooth objects but then Mustangs "bug" would come in useful.