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Old 18th August 2004, 07:17   #6
vanderphunck
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Join Date: Jul 2004
Location: Finland
Posts: 47
for a simple tunnel effect you'd want to do something like this:

x=f(angle relative to center)
y=g(distance from center)


Where f and g are 2 appropriate functions. Below is an example that works:

r=atan2(y,x);
d=sqrt(sqr(x)+sqr(y));
x=abs(r*4/$pi); //could also just be r but this looks better...
y=1/d;


Then to avoid the aliasing noise near the center you might want to set alpha to some function of d.
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