I am pleased to offer for discussion, dissection, and debate a set of 
files for rendering the mandelbulb fractal in POV-Ray.  The heart of it 
can be put into a single standalone file, the SDL version of which I 
have reproduced at the bottom of this message.  The rest of the example 
scene files, and a few other goodies including a long README.TXT, are 
zipped up and posted to p.b.scene-files.

http://news.povray.org/povray.binaries.scene-files/thread/%3C4b2c7b3f%40news.povray.org%3E/

In this zip you can also find files to patch beta 34 for about a 6x 
speedup by compiling the function internally, but I have also included 
SDL-only versions like the one below that work just fine with POVRay 
3.6.1 for MS Windows, and in the unpatched 3.7 beta in both MSW and 
Linux.  (These are the only systems I have tested.)  All of these files 
render in minutes (some in seconds) at 320x240 without anti-aliasing.

Ultimately, if the source code patch in the following post to this 
thread can be made acceptable, I would like to post it to p.u.patches 
and hope for its inclusion in an upcoming version of POV-Ray.

I appreciate your comments and critiques.

~David Wagner

//--- Start of file ---

// Persistence of Vision Ray Tracer Scene Description File
// File: mbsdl_standalone.pov
// Vers: 3.6, 3.7
// Desc: Minimal Stand-alone Mandelbulb Scene Example
// Date: 12/18/09
// Auth: David Wagner
// Cite: http://www.skytopia.com/project/fractal/2mandelbulb.html

// WARNING: Declare this function definition first in a scene.
// WARNING: This recursive function is invalid SDL and can crash POV-Ray.

#declare mbsdl_recurse = function( mbsdl_r_p_r, mbsdl_r_p_theta, 
mbsdl_r_p_phi, mbsdl_r_i,mbsdl_r_i_bailout, mbsdl_r_r2_bailout, x,y,z, 
mbsdl_r_x,mbsdl_r_y,mbsdl_r_z) {
    select(mbsdl_r_i > mbsdl_r_i_bailout | pow(mbsdl_r_x,2) + 
pow(mbsdl_r_y,2) + pow(mbsdl_r_z,2) >mbsdl_r_r2_bailout, 0,
       mbsdl_recurse( mbsdl_r_p_r,mbsdl_r_p_theta, mbsdl_r_p_phi, 
mbsdl_r_i+1,mbsdl_r_i_bailout, mbsdl_r_r2_bailout, x,y,z,

          x + pow(pow(mbsdl_r_x,2) + pow(mbsdl_r_y,2) + pow(mbsdl_r_z,2) 
, 0.5*mbsdl_r_p_r)
              * sin( atan2( sqrt(pow(mbsdl_r_x,2) + pow(mbsdl_r_y,2)), 
mbsdl_r_z) * mbsdl_r_p_theta)
              * cos( atan2(mbsdl_r_y,mbsdl_r_x) * mbsdl_r_p_phi),

          y + pow(pow(mbsdl_r_x,2) + pow(mbsdl_r_y,2) + pow(mbsdl_r_z,2) 
, 0.5*mbsdl_r_p_r)
              * sin( atan2( sqrt(pow(mbsdl_r_x,2) + pow(mbsdl_r_y,2)), 
mbsdl_r_z) * mbsdl_r_p_theta)
              * sin( atan2(mbsdl_r_y,mbsdl_r_x) * mbsdl_r_p_phi),

          z + pow(pow(mbsdl_r_x,2) + pow(mbsdl_r_y,2) + pow(mbsdl_r_z,2) 
, 0.5*mbsdl_r_p_r)
              * cos( atan2( sqrt(pow(mbsdl_r_x,2) + pow(mbsdl_r_y,2)), 
mbsdl_r_z) * mbsdl_r_p_theta)
       ),
       1/( mbsdl_r_i+log(log(mbsdl_r_r2_bailout) / 
log((mbsdl_r_i>(mbsdl_r_i_bailout-1))+pow(mbsdl_r_x,2)+pow(mbsdl_r_y,2)+pow(mbsdl_r_z,2)))

/ log(mbsdl_r_p_r) )
    )//end recursion select loop
};

#declare f_mandelbulb = function(x,y,z, mbsdl_f_p_r, mbsdl_f_p_theta, 
mbsdl_f_p_phi,  mbsdl_f_i_bailout, mbsdl_f_r_bailout){
     mbsdl_recurse( mbsdl_f_p_r, mbsdl_f_p_theta, 
mbsdl_f_p_phi,1,int(mbsdl_f_i_bailout-1), pow(mbsdl_f_r_bailout,2), 
x,y,z, x,y,z)
}

isosurface {
    function{f_mandelbulb(x,y,z, 8,8,8, 3, 3)}
    threshold 1/3.1
    max_gradient 20
    accuracy 0.001
    contained_by{sphere{<0,0,0>,1.2}}
    texture{
       pigment{rgb<1,1,1>}
    }
}

light_source {
    <-30, 30, -30>
    color rgb <1, 1, 1>
    translate <-30, 30, -30>
}

camera {
    location  <0.0, 0.5, -4.0>
    direction 1.5*z
    right     x*image_width/image_height
    look_at   <0.0, 0.0,  0.0>
}

//--- End of File ---

Post a reply to this message