/*
  Returns the closest distance between point pnt and the segment
  that goes from point a to b
  Idea by:
  http://local.wasp.uwa.edu.au/~pbourke/geometry/pointline/
 */
double distance_point_to_segment(const point &a,const point &b,
                                 const point &pnt){
  double u =
    ((pnt.x - a.x)*(b.x - a.x) + (pnt.y - a.y)*(b.y - a.y))
    /distsqr(a, b);
  point intersection;
  intersection.x = a.x + u*(b.x - a.x);
  intersection.y = a.y + u*(b.y - a.y);
  if (u < 0.0 || u > 1.0){
    return min(dist(a, pnt), dist(b, pnt));
  }
  return dist(pnt, intersection);
}
Exemplo n.º 2
0
bool graham_cmp(point a, point b) {
	int t = cross(pivot, b, a);
	if(t < 0) return true;
	if(t == 0) return distsqr(pivot, a) < distsqr(pivot, b);
	return false;
}