--BRUSH Scene: Mandelbrot fractal v0.5
--
--Draws a Mandelbrot fractal in the current 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
colors = 64
x0 = -1.7
x1 = 0.7
ym = 0
iter = 64
ok, x0, x1, ym, iter = inputbox("Fractal data",
"X0", x0, -2, 2,4,
"X1", x1, -2, 2,4,
"midY", ym, -2, 2,4,
"Iter", iter, 1, 2048,0
);
-- -0.831116819,-0.831116815,0.2292112435,192
function mandel(x,y,l,r,o,i) -- pos. as fraction of 1, left coord, right coord, y coord, iterations
local w,s,a,p,q,n,v,w
s=math.abs(r-l);
a = l + s*x;
p = a;
b = o - s*(y-0.5);
q = b;
n = 1;
v = 0;
w = 0;
while (v+w<4 and n<i) do n=n+1; v=p*p; w=q*q; q=2*p*q+b; p=v-w+a; end;
return n
end
w, h = getbrushsize()
for x = 0, w - 1, 1 do
for y = 0, h - 1, 1 do
q = mandel(x/w,y/h,x0,x1,ym,iter) % colors;
putbrushpixel(x, y, q);
end
end