"Tim Cook" <z99### [at] bellsouthnet> schrieb im Newsbeitrag 
news:42351d76$1@news.povray.org...
> Is there any particular reason the maximum for this is 1600?

I think the reason for this limit is, that at the moment the
sample-directions for radiosity calculations are hardcoded into
the sourcecode, therefore it's not possible to use a higher
count than 1600. Basically, if you set 'count N' then POV-Ray
will take the first N Samples from the internal sample-set to
scan the hemisphere.


> ...  Therefore, I see no reason to prevent a user from setting
> radiosity count to as high a number as they feel is necessary and have 
> patience and/or memory to accomodate.

MegaPOV 1.1 has the feature, that you can define a custom
sample-set. So you have perfect control over the sample-directions
and also the maximum number of samples isn't bounded anymore.
I've written some code to generate a fairly good distributed
sample-set with arbitrary count. It can be found at:
http://www.8ung.at/halcyon/povray/custom-radiosity.html
(in the case that the website isn't working, i've attached the
relevant code)

> Tim Cook
Thies Heidecke



usage:
SunflowerRadiosity(600, 0.0, seed(23))

'sunflower.inc':
-----------------------------------------------------------------
#version unofficial MegaPOV 1.10;

#include "rand.inc"

#macro SunflowerRadiosity(RadiositySamples, RadJitter, RandomStream)
  samples {
    RadiositySamples, // number of directions given
    #declare gsa= 2*pi*((sqrt(5)-1)/2);  // golden section angle
    #declare N  = RadiositySamples; // Number of Samples
    #declare M  = 1;
    #declare phi= gsa;
    #declare pr = sqrt(M/N);

    #while(M<N)
      //<pr*sin(phi),pr*cos(phi),sqrt(1-pr*pr)>,
      #local pos = 2*x;
      #while(vlength(pos)>=1)
        #local pos = pr*<sin(phi),cos(phi),0> + 
Rand_Gauss(0,RadJitter/3,RandomStream)*vrotate(y,360*rand(RandomStream)*z)/sqrt(N);
        //#local pos = pr*<sin(phi),cos(phi),0> + 
RadJitter*vrotate(y,360*rand(RandomStream)*z)/sqrt(N);
      #end
      <pos.x,pos.y,sqrt(1-(pow(pos.x,2)+pow(pos.y,2)))>,
      #declare M=M+1;
      #declare pr=sqrt(M/N);
      #declare phi=phi+gsa;
    #end
    #if(RadiositySamples>1)
      <0,1/sqrt(N),sqrt(1-1/N)>
    #else
      <0,0,1>
    #end
  }
  count RadiositySamples
#end

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