--BRUSH Scene: Amigaball 1.0
--
--Draws the famous 'Amiga ball' in the brush.
--
--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/>
-- This script was adopted from Evalion, a Javascript codecrafting/imageprocessing project
--http://goto.glocalnet.net/richard_fhager/evalion/evalion.html
w, h = getbrushsize()
if (w<64 or h<64) then
setbrushsize(64,64)
w=64
h=64
end
for y = 0, h - 1, 1 do
for x = 0, w - 1, 1 do
-- Fractionalize image dimensions
ox = x / w;
oy = y / h;
-- Ball
Xr = ox-0.5; Yr = oy-0.5;
W = (1 - 2*math.sqrt(Xr*Xr + Yr*Yr));
-- 'FishEye' distortion / Fake 3D
F = (math.cos((ox-0.5)*math.pi)*math.cos((oy-0.5)*math.pi))*0.65;
ox = ox - (ox-0.5)*F;
oy = oy - (oy-0.5)*F;
-- Checkers
V = ((math.floor(0.25+ox*10)+math.floor(1+oy*10)) % 2) * 255 * W;
-- Specularities
SPEC1 = math.max(0,(1-5*math.sqrt((ox-0.45)*(ox-0.45)+(oy-0.45)*(oy-0.45)))*112);
SPEC2 = math.max(0,(1-15*math.sqrt((ox-0.49)*(ox-0.49)+(oy-0.48)*(oy-0.48)))*255);
r = W * 255 + SPEC1 + SPEC2
g = V + SPEC1 + SPEC2
b = V + SPEC1 + SPEC2
putbrushpixel(x, y, matchcolor(r,g,b));
end
end