| Re: [AD] patches for color.c and graphics.c |
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- To: Coordination of admins/developers of the game programming library Allegro <alleg-developers@xxxxxxxxxx>
- Subject: Re: [AD] patches for color.c and graphics.c
- From: Elias Pschernig <elias@xxxxxxxxxx>
- Date: Fri, 01 Dec 2006 10:18:46 +0100
On Fri, 2006-12-01 at 01:42 -0600, Robert Jr Ohannessian wrote:
> I think we should switch to round(x * 255.0 / 63) (or strictly
> equivalent non-floating point function), to match every other reasonable
> graphics API (and hardware) on the planet.
Yes. In fact, I converted all 256 values to 6-bit and back to 8-bit, and
summed up how much the value would go over the original value, and how
much below. The results:
*255/63: +90 -270 (standard deviation: 1.479)
<<2 + >>4: +160 -160 (standard deviation: 1.581)
Bob's way: +150 -150 (standard deviation: 1.479)
So there's a clear winner, which would explain why everyone uses it.
I'll try to make another patch (although of course, visually, hardly any
difference can be seen again)..
--
Elias Pschernig