| Re: [AD] improvements on alpha blending... |
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Vincent Penquerc'h wrote:
> I think the original poster meant whether the new bit (most
> significant bit in a right shift) would get zeroed (as would happen if
> the number was positive (in a 2s complement encoding) or set to 1
> (thus preserving the original number's signedness).
But our numbers are only positive, so this doesn't have any effect.
(Note that this does not mean that the compiler can optimize a division
to a shift: even if _we_ know the numbers are positive because of the
way we designed the algorithm, it does not mean that the compiler can
figure this out at compile time.) Allegro uses shifts all over, so I
think if there would be a problem in colblend.c then it would be so at
many other places as well.
Sven