I'm trying to repeat an object just a certain number of times and transform it arbitrarily. I know of a simple way to do it by just repeating it's calculation and using the min function but then I would need to cycle through its loop every time it repeated the object. For example:
float DE(vec3 z)
{
float r;
z += Position;
if (Tile.w == 1) z = abs(-Tile.zyx-mod(z,2.0* -Tile.zyx));
else if (Tile.w == 2) z = abs(2.0*Tile.zyx-mod(z-Tile.zyx,Tile.zyx*4.0))-Tile.zyx;
z = z * fullRotate;
// Iterate to compute the distance estimator.
int n = 0;
while (n < Iterations) {
z *= fracRotation1;
if (z.x+z.y<0.0) z.xy = -z.yx;
if (z.x-z.y<0.0) z.xy = z.yx;
if (z.x-z.z<0.0) z.xz = z.zx;
z = ((z+Julia*.25)*Scale - offset*(Scale-1.0)) * (Fold.xyz * .2 + 1);
z *= fracRotation2;
r = dot(z, z);
if (n< ColorIterations) orbitTrap = min(orbitTrap, abs(vec4(z,r)));
n++;
}
orbitTrap*=ColorScale+ColorOffset;
return length(z) * pow(Scale, -float(n));
}
if I replace the return statement with : return min(length(z),length(z+offset) * pow(Scale, -float(n));
I do not get the desired result (a second pyramid offset from the first), in fact it seems to create a small offset within the iteration. But then I can't find a way to repeat the pyramid before the iteration, all the info I've found on mixing DEs works on the float output not on the position input. As I said earlier I'm sure if I pack the DE into a function and call it more than once then use the min operator it will work but I think this will increase the render time much more than finding a way to repeat its output?
Any suggestions or ideas?
Also if someone has a better method for a Sierpinski pyramid I'd be stoked to hear what you have to say. The above code is just the modified Octahedron code from Fragmentarium and I seem to have a problem with it not cutting holes out of the bottom. I've done some reading on folding on the Syntopia blog but I'm still not 100% there yet.
thanks
Keith
September 05, 2010, 07:06:33 PM
t-repeat
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