public static void swapEdge(QuadEdge e) {
QuadEdge a = e.oprev();
QuadEdge b = e.sym().oprev();
splice(e, a);
splice(e.sym(), b);
splice(e, a.lnext());
splice(e.sym(), b.lnext());
e.orig = a.dest();
e.sym().orig = b.dest();
}
/**
* Test if the Point p is at the right of the QuadEdge q.
*
* @param QuadEdge reference
* @param p Point to test
* @return true/false
*/
public static boolean isAtRightOf(QuadEdge q, Point p) {
return isCounterClockwise(p, q.dest(), q.orig());
}
/**
* Test if the Point p is on the line porting the edge
*
* @param e QuadEdge
* @param p Point to test
* @return true/false
*/
public static boolean isOnLine(QuadEdge e, Point p) {
// test if the vector product is zero
if ((p.x - e.orig().x) * (p.y - e.dest().y) == (p.y - e.orig().y) * (p.x - e.dest().x))
return true;
return false;
}
/**
* Create a new QuadEdge by connecting 2 QuadEdges
*
* @param e1,e2 the 2 QuadEdges to connect
* @return the new QuadEdge
*/
public static QuadEdge connect(QuadEdge e1, QuadEdge e2) {
QuadEdge q = makeEdge(e1.dest(), e2.orig());
splice(q, e1.lnext());
splice(q.sym(), e2);
return q;
}