public int edgeIndex(TriangulationPoint p1,TriangulationPoint p2){
  if (points[0] == p1) {
    if (points[1] == p2) {
      return 2;
    }
 else     if (points[2] == p2) {
      return 1;
    }
  }
 else   if (points[1] == p1) {
    if (points[2] == p2) {
      return 0;
    }
 else     if (points[0] == p2) {
      return 2;
    }
  }
 else   if (points[2] == p1) {
    if (points[0] == p2) {
      return 1;
    }
 else     if (points[1] == p2) {
      return 0;
    }
  }
  return -1;
}

public int edgeIndex ( TriangulationPoint p1 , TriangulationPoint p2 ) { if ( points [ 0 ] == p1 ) { if ( points [ 1 ] == p2 ) { return 2 ; } else if ( points [ 2 ] == p2 ) { return 1 ; } } else if ( points [ 1 ] == p1 ) { if ( points [ 2 ] == p2 ) { return 0 ; } else if ( points [ 0 ] == p2 ) { return 2 ; } } else if ( points [ 2 ] == p1 ) { if ( points [ 0 ] == p2 ) { return 1 ; } else if ( points [ 1 ] == p2 ) { return 0 ; } } return - 1 ; }
get the neighbor that share this edge
