Am 22.11.2011 09:59, schrieb Jaime Vives Piqueres:
> The animation shows a 3D fractal created with Mandelbulber, which
> looks truly impressive... I've just downloaded it, and I can't stop
> playing with it. It's a shame that I cannot export these things to
> POV-Ray for a better texturing work... because I lack the skills to
> create them from the scratch, as you did.
>
> --
> Jaime

Yeah, Mandelbulber is fun!

Maybe you are able to come up with some more interesting texture work 
than I did as I was mostly interested in the formula itself after having 
played with Mandelbulber.

This is my try on doing it within POV-SDL. It needs some toying around 
with the isosurface parameters (and the iteration limit) for closeup views.

-Ive


========================================================================+

#declare fm_recurse = function(Iteration, IterationBailout, x,y,z, MB_x, 
MB_y, MB_z) {

    select(Iteration > IterationBailout | pow(MB_x,2) + pow(MB_y,2) + 
pow(MB_z,2) > 2, 0,

       fm_recurse(Iteration+1, IterationBailout, x,y,z,

          x + pow(pow(MB_x,2) + pow(MB_y,2) + pow(MB_z,2), 4)
              * sin( atan2(sqrt(pow(MB_x,2) + pow(MB_y,2)), MB_z) * 8)
              * cos( atan2(MB_y, MB_x) * 8),

          y + pow(pow(MB_x,2) + pow(MB_y,2) + pow(MB_z,2), 4)
              * sin( atan2( sqrt(pow(MB_x,2) + pow(MB_y,2)), MB_z) * 8)
              * sin( atan2(MB_y,MB_x) * 8),

          z + pow(pow(MB_x,2) + pow(MB_y,2) + pow(MB_z,2), 4)
              * cos( atan2( sqrt(pow(MB_x,2) + pow(MB_y,2)), MB_z) * 8)

       ),

       1 / (Iteration + log(L2 / log((Iteration > (Iteration-1)) + 
pow(MB_x,2) + pow(MB_y,2) + pow(MB_z,2))) / L8)

    )
};


#declare f_mandelbulb = function(x,y,z, MaxIterations) {
     fm_recurse (1, int(MaxIterations-1), x,y,z, x,y,z)
}


#declare Mandelbulp = isosurface {
   function {f_mandelbulb(x,y,z, 10)}  // MaxIterations = 10
   threshold 0.17
   max_gradient 12
   accuracy 0.001
   contained_by {sphere {0, 1.2} }
/*
   texture {
     pigment {
       function { f_mandelbulb(x,y,z, 5) } sine_wave
       scale 1
       frequency 4
       color_map {
         [0.00 rgb <0.7, 0.4, 0.1> ]
         [1.00 rgb <0.9, 0.2, 0.0> ]
       }
     }
     finish {
       ambient 0  diffuse 0.9  specular 0 roughness 0.02
     }
   }
*/

   texture {
     pigment {
       spherical
       color_map {
         [0.00 rgb <0.0, 0.6, 0.2> ]
         [0.26 rgb <0.7, 0.4, 0.1> ]
         [1.00 rgb <0.5, 0.1, 0.0> ]
       }
       turbulence 0.11
       scale 1.2
     }

     finish {
       ambient 0  diffuse 1
     }
   }
}

========================================================================+

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