// Worley noise: example of worley noise with euclidean distance function by Rocchini

#include <stdio.h>
#include <stdlib.h> // rand
#include <time.h>
#include <math.h>

int main() {
	const int S = 1024;		// image Size
	const int N  = 128;		// Number of points
	const int K  = 2;		// color value sKale
	int x[N],y[N];		// points positions
	int i,j,k;
	
	
	srand(time(NULL));   // Initialization, should only be called once.
	for(i=0;i<N;++i){ x[i] = rand()%S; y[i] = rand()%S; }

	FILE * fo = fopen("worley.pnm","wb");
	fprintf(fo,"P5\n %d %d\n255\n",S,S);

	for(j=0;j<S;++j) 
		for(i=0;i<S;++i){		// for each pixel...
			int mind = S;
			for(k=0;k<N;++k) {					// compute min distance
				int dx = i-x[k];
				int dy = j-y[k];
				int d = (int)sqrt((double)(dx*dx+dy*dy));
				if(mind>d) mind = d;
			}
		
		mind *= K;							// scale and clip
		unsigned char b = mind<255 ? mind : 255;
		fwrite(&b,1,1,fo);
	}
	fclose(fo);
	
	return 0;
}