AutoStereogram

#include <algorithm>

// Source
// https://www.nottingham.ac.uk/~etzpc/nz/sirds/creation.html#Subject22

static int round(int X) {
    return (int)((X)+0.5);
}
static const int DPI = 72;
static float E = round(2.5 * DPI);
static float mu = (1/3.0);
static float separation(float Z) {
    return round((1-mu*Z)*E/(2-mu*Z));
}
static float far = separation(0);

//#define maxX 256
//#define maxY 256

static void DrawAutoStereogram(float **Z, int maxX, int maxY, int **out)
{
  int x, y;
  for( y = 0; y < maxY; y++ ) {
    int pix[maxX];
    int same[maxX];
    int s;
    int left, right;

    /* initialise the links */
    for( x = 0; x < maxX; x++ )
      same[x] = x;

    /* calculate the links for the Z[][] object */
    for( x = 0; x < maxX; x++ ) {
      s = separation(Z[x][y]);
      left = x - (s/2);
      right = left + s;
      if( 0 <= left && right < maxX ){
    { int k;
      for(k=same[left]; k!=left && k!=right; k=same[left])
        if( k < right )
          left = k;
        else {
          left = right;
          right = k;
        }
      same[left] = right;
    }
      }
    }

    /* assign the colors */
    for( x = maxX-1; x >= 0; x-- ) {
      if( same[x] == x ) pix[x] = random()&1;
      else pix[x] = pix[same[x]];
        
        out[x][y] = pix[x];
        
//      Set_Pixel(x, y, pix[x]);
    }
  }
}