#include "stdio.h"
#include "stdlib.h"
#include "math.h"
#include "paulslib.h"

/*
   Example that creates the burning ship fractal
   and saves it as a raw image file.
*/

typedef struct {
   char r,g,b;
} BYTECOLOUR;
#define MAXGRID 100
BYTECOLOUR image[MAXGRID][MAXGRID];

int main(int argc,char **argv)
{
   int i,j,k,kmax=250;
   FILE *fptr;
   double dcx,dcy,dxy;
   double value;
   double cx,cy,xi,yi,xip1,yip1;

   if (argc < 5) {
      fprintf(stderr,"Usage: %s cx cy dxy outfilename\n",argv[0]);
      exit(0);
   }
   dcx = atof(argv[1]);
   dcy = atof(argv[2]);
   dxy = atof(argv[3]);

   for (j=0;j<MAXGRID;j++) {
      cy = dcy + (j - MAXGRID/2) * dxy / (double)MAXGRID;

      for (i=0;i<MAXGRID;i++) {
         cx = dcx + (i - MAXGRID/2) * dxy / (double)MAXGRID;

         xi = 0;
         yi = 0;
         for (k=0;k<kmax;k++) {
            xip1 = xi*xi - yi*yi - cx;
            yip1 = 2 * ABS(xi*yi) - cy;
            xi = xip1;
            yi = yip1;
            if (xi*xi + yi*yi > 200)
               break;
         }
         value = sqrt(k / (double)kmax);
         value *= value;
         image[i][j].r = 255 * value;
         image[i][j].g = image[i][j].r;
         image[i][j].b = image[i][j].r;
      }
   }

   fprintf(stderr,"Writing output image\n");
   if ((fptr = fopen(argv[4],"w")) == NULL) {
      fprintf(stderr,"Error occured writing the image\n");
      exit(0);
   }
   for (j=0;j<MAXGRID;j++) {
      for (i=0;i<MAXGRID;i++) {
         fputc(image[i][MAXGRID-1-j].r,fptr);
/*
         fputc(image[i][j].g,fptr);
         fputc(image[i][j].b,fptr);
*/
      }
   }
   fclose(fptr);
}