Chris Johnson nous apporta ses lumieres ainsi en ce 2004/05/03 15:44... :

>I haven't seen an algorithm for it specifically, though an example was on
>p.binaries.animations a while ago.
>
>Heres some C code - I've typed this straight into the post so there could
>well be typos, but I think the overall idea is right:
>
>typedef struct
>{
>   float x,y,z;
>} point;
>
>int maxPoints=60000;
>point *points;
>====> points=(point *)malloc(maxPoints*sizeof(point));
>float repulseCoeff = 0.1;
>int maxIterations = 50;
>float dd;
>
>// Initially distribute points randomly on sphere
>for (int n=0; n<maxPoints; n++)
>{
>    do
>    {
>        points[n].x = frnd(2)-1;   // frnd(float max) generates random
>number between 0 and max
>        points[n].y = frnd(2)-1;
>        points[n].z = frnd(2)-1;
>    }
>    while (sq(points[n].x)+sq(points[n].y)+sq(points[n].z)>1)
>}
>
>for (int i=0; i<maxIterations; i++) // Iterate this bit a few times
>{
>    for (int n=0; n<maxPoints; n++)
>    {
>        for (int m=n+1; m<maxPoints; m++) // for each pair of points...
>        {
>            // make them repulse each other, without a restriction that they
>stay on the sphere
>
>dd=sq(points[n].x-points[m].x)+sq(points[n].y-points[m].y)+sq(points[n].z-po
>ints[m].z);
>            points[n].x += (points[n].x-points[m].x)*repulseCoeff/dd;
>            points[n].y += (points[n].y-points[m].y)*repulseCoeff/dd;
>            points[n].z += (points[n].z-points[m].z)*repulseCoeff/dd;
>            points[m].x -= (points[n].x-points[m].x)*repulseCoeff/dd;
>            points[m].y -= (points[n].y-points[m].y)*repulseCoeff/dd;
>            points[m].z -= (points[n].z-points[m].z)*repulseCoeff/dd;
>        }
>    }
>
>    for (int n=0; n<maxPoints; n++) // for each point
>    {
>        // stick it back onto the sphere
>        dd = sqrt(sq(points[n].x)+sq(points[n].y)+sq(points[n].z));
>        points[n].x/=dd;
>        points[n].y/=dd;
>        points[n].z/=dd;
>    }
>}
>
>-Chris
>
>
>  
>
There is a bug, using "malloc" and never freeing the allocated memory = 
memory leak.

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