65 lines
1.2 KiB
Lua
65 lines
1.2 KiB
Lua
-- Picture scene: Amigaball (by Richard Fhager, code adopted from Evalion)
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w = 256
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h = 256
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setpicturesize(w,h)
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-- Set Amiga Palette
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colors = {}
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for c = 0, 63, 1 do
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colors[c+1] = {c*4,0,0}
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end
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for c = 0, 63, 1 do
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colors[c+65] = {255,c*4,c*4}
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end
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for c = 0, 63, 1 do
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colors[c+129] = {255-c*4,255-c*4,255-c*4}
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end
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for c = 1, #colors, 1 do
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setcolor(c-1,colors[c][1],colors[c][2],colors[c][3])
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end
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-- Make Amiga ball
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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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c = matchcolor(r,g,b)
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putpicturepixel(x, y, c);
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end
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end
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