On the iPhone Simulator if I use a lowp variable to accumulate a colour result, in something like a “god ray” or blur shader I get a saturated result, ultimately. No matter how many reasonable iterations I carry out.
On iOS devices, however, I get a ‘0’ result, which I can only assume is because of some kind of overflow situation. Replacing the lowp with a medium solves the problem.
I don’t mind which happens, and can see reasons for either.
I am just curious as to what the “expected” result is from Imagination’s perspective…scratt2011-02-16 09:20:44