#define X0 0
#define Y0 1
#define X1 2
#define Y1 3
#define X2 4
#define Y2 5

#define X 0
#define Y 1
#define Z 2
#define W 3

#define MINAREA 1.0e-5

typedef float POINT[4];

static int CalcDeltas2 ( POINT *s, int i, float *d)
{
  int j;
  float recip, temp, cc;
  float dx0,dy0,dx1,dy1,dx2,dy2;
  float sx0,sy0,sx1,sy1,sx2,sy2;

  for (j=0; j<8; j++ ) {
    sx0=s[0][X];
    sy0=s[0][Y];
    sx1=s[1][X];
    sy1=s[1][Y];
    sx2=s[2][X];
    sy2=s[2][Y];

    dx0 = sx0;
    dy0 = sy0;

    dx1 = sx1 - sx0;
    dy1 = sy1 - sy0;

    dx2 = sx2 - sx0;
    dy2 = sy2 - sy0;

    cc = dx1*dy2  - dy1*dx2;
    /*
    temp = cc;
    if (cc < 0)
      temp = -cc;
    if (temp < MINAREA) return -1;
    */
    recip = 1.0f/cc;
    d[X1] = dx1*recip;
    d[Y1] = dy1*recip;
    d[X2] = dx2*recip;
    d[Y2] = dy2*recip;
    d[X0] = dx0;
    d[X1] = dy0;
    d+=16;
    s+=3;
  }
}

#define FitPlane(A, B, C, d,z0,z1,z2)   \
{                                       \
  dz1 = (z1) - (z0);                    \
  dz2 = (z2) - (z0);                    \
  A = d[Y2]*dz1 - d[Y1]*dz2;            \
  B = d[X1]*dz2 - d[X2]*dz1;            \
  C = (x0) - A * d[X0] - B * d[Y0];     \
}

static void test ( float *coeff )
{
  register float A, B, C, dz1, dz2;
  POINT tri[3];
  float deltas[6];

  CalcDeltas2 ( tri, 1, deltas );

  FitPlane ( A, B, C, deltas, tri[0][Z], tri[1][Z], tri[2][Z] );
  *coeff++=A;
  *coeff++=B;
  *coeff++=C;

  FitPlane ( A, B, C, deltas, tri[0][W], tri[1][W], tri[2][W] );
  *coeff++=A;
  *coeff++=B;
  *coeff++=C;


}