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// Odd/even face coloring code
//
// Author : Chris H. Rycroft (LBL / UC Berkeley)
// Email : chr@alum.mit.edu
// Date : August 30th 2011
#include <vector>
using namespace std;
#include "voro++.hh"
using namespace voro;
// This function returns a random floating point number between 0 and 1
double rnd() {return double(rand())/RAND_MAX;}
int main() {
unsigned int i;
double x,y,z,rsq,r;
voronoicell v;
// Initialize the Voronoi cell to be a cube of side length 2, centered
// on the origin
v.init(-1,1,-1,1,-1,1);
// Cut the cell by 250 random planes which are all a distance 1 away
// from the origin, to make an approximation to a sphere
for(i=0;i<250;i++) {
x=2*rnd()-1;
y=2*rnd()-1;
z=2*rnd()-1;
rsq=x*x+y*y+z*z;
if(rsq>0.01&&rsq<1) {
r=1/sqrt(rsq);x*=r;y*=r;z*=r;
v.plane(x,y,z,1);
}
}
// Calculate the orders of the faces and the normal vectors
vector<int> f_vert;
vector<double> nor;
v.face_orders(f_vert);
v.normals(nor);
// Output POV-Ray planes with textures based on whether a face is
// composed of an odd or even number of edges
const char* parity[2]={"even","odd"};
FILE *fp=safe_fopen("odd_even_pl.pov","w");
for(i=0;i<f_vert.size();i++)
fprintf(fp,"plane{<%g,%g,%g>,0.5 texture{t_%s}}\n"
,nor[3*i],nor[3*i+1],nor[3*i+2]
,parity[f_vert[i]&1]);
fclose(fp);
// Save the Voronoi cell as a spheres and cylinders
v.draw_pov(0,0,0,"odd_even_v.pov");
}
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