"Indra's" Fractal Volumetric Shader

[tree3d]

Hi all,

Here’s a version of a fractal variation that i’ve found at shadertoy and adapted to Blender OSL:

Shadertoy

All is due to the shoulders of the giants we are standing on.

shader IndrasF(
    float ITER = 12,
    float SCALE = -2.25,
    float Fact = 2.0,
    vector CSize = vector(1.3, 1.7, 1.3),
    output closure color CL = holdout()
) {
    float m r= 0.25, mxr = 1.2;
    
    float pFractal(point P) {
        float scale = 1.0;
        
        vector p = vector(P[0], P[2], P[1]);
        p*=SCALE/clamp(dot(p,p),mr,mxr);
        
        
        for(int i = 0; i < ITER; i++) {
            p = 2.0*clamp(p, -CSize, CSize) - p;
            float r2 = dot(p,p);
            float k = max((2.)/(r2), .027);
            p     *= k;
            scale *= k;
        }
        
        float l = length(p) - 3.5;
        float rxy = l - 2.0;
        float n = l * p[2];
        rxy = max(rxy, -(n) / 2.);
        return (rxy) / abs(scale);
    }   
     
    float fractal = pFractal(I * Fact);
    float fractal_glow = pFractal(P*Fact);
    float fractal_cross = pFractal(cross(I,P)*Fact);
     
    CL =  emission() * color(clamp(fractal, .0,1), .0, .0)*20+emission()*color(.0, clamp(pow(fractal*2, 2.), .0, .02), .0);
    return;
}

One of the results may be:

But there’s alot to be discovered with this one.

Cheers!

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