/* Linear moire pattern generator.

   ./linear_moire_bw <width> <height> > output.pgm

   This is same as linear_moire.c, except output is black and white
   instead of grayscale.
                                                                    */
#include<math.h>
#include<stdio.h>
#include<stdlib.h>
#include<time.h>
#ifdef _WIN32
   #include<fcntl.h>
   #include<io.h>
#endif

#define PI          3.14159265358979323846264338327950288419716939937510
#define LINE_COUNT  3

int main(int argc, char **argv)
{
   int width, height, x, y, i;
   double rx[LINE_COUNT], ry[LINE_COUNT], phase[LINE_COUNT], a, s;

   if( argc != 3 ||
       (width = atoi(argv[1])) <= 0 ||
       (height = atoi(argv[2])) <= 0 )
   {
      return printf("%s <width> <height>\n", *argv);
   }
   if( width >= 0x8000 || height >= 0x8000 )
      return !puts("Output size too large.");

   #ifdef _WIN32
      setmode(STDOUT_FILENO, O_BINARY);
   #endif

   srand(time(NULL));

   for(i = 0; i < LINE_COUNT; i++)
   {
      s = ((double)rand() / RAND_MAX * 40.0 + 12.0) /
          (width < height ? width : height);
      a = (double)rand() / RAND_MAX * PI * 2.0;
      rx[i] = s * cos(a);
      ry[i] = s * sin(a);
      phase[i] = (double)rand() / RAND_MAX * PI * 2.0;
   }

   printf("P5\n%d %d\n255\n", width, height);
   for(y = 0; y < height; y++)
   {
      for(x = 0; x < width; x++)
      {
         a = 0;
         for(i = 0; i < LINE_COUNT; i++)
            a += sin(x * rx[i] + y * ry[i] + phase[i]) + 1.0;
         fputc((double)rand() / RAND_MAX * 2.0 * LINE_COUNT > a ? 0 : 255,
               stdout);
      }
   }
   return 0;
}