58 lines
1.4 KiB
Lua
58 lines
1.4 KiB
Lua
--BRUSH Scene: Amigaball 1.0
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--
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--Draws the famous 'Amiga ball' in the brush.
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--
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--by Richard Fhager
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--http://hem.fyristorg.com/dawnbringer/
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-- Copyright 2010 Richard Fhager
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--
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-- This program is free software; you can redistribute it and/or
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-- modify it under the terms of the GNU General Public License
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-- as published by the Free Software Foundation; version 2
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-- of the License. See <http://www.gnu.org/licenses/>
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-- This script was adopted from Evalion, a Javascript codecrafting/imageprocessing project
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--http://goto.glocalnet.net/richard_fhager/evalion/evalion.html
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w, h = getbrushsize()
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if (w<64 or h<64) then
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setbrushsize(64,64)
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w=64
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h=64
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end
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for y = 0, h - 1, 1 do
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for x = 0, w - 1, 1 do
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-- Fractionalize image dimensions
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ox = x / w;
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oy = y / h;
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-- Ball
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Xr = ox-0.5; Yr = oy-0.5;
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W = (1 - 2*math.sqrt(Xr*Xr + Yr*Yr));
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-- 'FishEye' distortion / Fake 3D
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F = (math.cos((ox-0.5)*math.pi)*math.cos((oy-0.5)*math.pi))*0.65;
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ox = ox - (ox-0.5)*F;
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oy = oy - (oy-0.5)*F;
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-- Checkers
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V = ((math.floor(0.25+ox*10)+math.floor(1+oy*10)) % 2) * 255 * W;
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-- Specularities
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SPEC1 = math.max(0,(1-5*math.sqrt((ox-0.45)*(ox-0.45)+(oy-0.45)*(oy-0.45)))*112);
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SPEC2 = math.max(0,(1-15*math.sqrt((ox-0.49)*(ox-0.49)+(oy-0.48)*(oy-0.48)))*255);
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r = W * 255 + SPEC1 + SPEC2
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g = V + SPEC1 + SPEC2
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b = V + SPEC1 + SPEC2
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putbrushpixel(x, y, matchcolor(r,g,b));
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end
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end
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