--SCENE: Remap pic 2 RGB, 1lineED-dith. (Same line simple error-diffusion dither)
--by Richard Fhager
--http://hem.fyristorg.com/dawnbringer/
-- Copyright 2010 Richard Fhager
--
-- This program is free software; you can redistribute it and/or
-- modify it under the terms of the GNU General Public License
-- as published by the Free Software Foundation; version 2
-- of the License. See <http://www.gnu.org/licenses/>
power = 0.615
c1 = 0.8 -- Error weight (white is green)
c2 = 0.2 -- RGB weight (white is r+g+b)
-- Set Palette (to a predefined one)
colors = {{ 0, 0, 0},
{255, 0, 0},
{ 0,255, 0},
{ 0, 0,255}
}
chm = {1,0,0}
for c = 1, #colors, 1 do
setcolor(c-1,colors[c][1],colors[c][2],colors[c][3])
end
for c = #colors, 255, 1 do
setcolor(c,0,0,0)
end
w, h = getpicturesize()
for y = 0, h - 1, 1 do
re = 0
ge = 0
be = 0
for x = (y%2), w - 1, 1 do
r,g,b = getbackupcolor(getbackuppixel(x,y));
rn = re * c1 + r * chm[1+(y+0+x)%3] * c2
gn = ge * c1 + g * chm[1+(y+1+x)%3] * c2
bn = be * c1 + b * chm[1+(y+2+x)%3] * c2
n = matchcolor(rn,gn,bn);
putpicturepixel(x, y, n);
rn,gn,bn = getcolor(getpicturepixel(x,y));
re = (re + (r - rn)) * power
ge = (ge + (g - gn)) * power
be = (be + (b - bn)) * power
end
end