Method intersect

src/LNLib/Algorithm/Voronoi.cpp:415–462

create a new site where the HalfEdges el1 and el2 intersect - note that the PointVDG in the argument list is not used, don't know why it's there

//create a new site where the HalfEdges el1 and el2 intersect - note that the PointVDG in the argument list is not used, don't know why it's there
struct LNLib::Site* LNLib::VoronoiDiagramGenerator::intersect(struct Halfedge* el1, struct Halfedge* el2, struct PointVDG* p)
{
	struct	Edge* e1, * e2, * e;
	struct  Halfedge* el;
	float d, xint, yint;
	int right_of_site;
	struct Site* v;

	e1 = el1->ELedge;
	e2 = el2->ELedge;
	if (e1 == (struct Edge*)NULL || e2 == (struct Edge*)NULL)
		return ((struct Site*)NULL);

	//if the two edges bisect the same parent, return null
	if (e1->reg[1] == e2->reg[1])
		return ((struct Site*)NULL);

	d = e1->a * e2->b - e1->b * e2->a;
	if (-1.0e-10 < d && d < 1.0e-10)
		return ((struct Site*)NULL);

	xint = (e1->c * e2->b - e2->c * e1->b) / d;
	yint = (e2->c * e1->a - e1->c * e2->a) / d;

	if ((e1->reg[1]->coord.y < e2->reg[1]->coord.y) ||
		(e1->reg[1]->coord.y == e2->reg[1]->coord.y &&
			e1->reg[1]->coord.x < e2->reg[1]->coord.x))
	{
		el = el1;
		e = e1;
	}
	else
	{
		el = el2;
		e = e2;
	};

	right_of_site = xint >= e->reg[1]->coord.x;
	if ((right_of_site && el->ELpm == le) || (!right_of_site && el->ELpm == re))
		return ((struct Site*)NULL);

	//create a new site at the point of intersection - this is a new vector event waiting to happen
	v = (struct Site*)getfree(&sfl);
	v->refcnt = 0;
	v->coord.x = xint;
	v->coord.y = yint;
	return(v);
}

/* returns 1 if p is to right of halfedge e */
int LNLib::VoronoiDiagramGenerator::right_of(struct Halfedge* el, struct PointVDG* p)