private VornoiEvent CalcEdgeEvents(Parabola parabola)
{
Parabola leftParabola = (Parabola)_linkedList.First((p) => p is Parabola && p != parabola && parabola.Focus.x > (p as Parabola).Focus.x);
Parabola rightParabola = (Parabola)_linkedList.First((p) => p is Parabola && p != parabola && parabola.Focus.x <= (p as Parabola).Focus.x);
var node = _linkedList.Find(parabola);
HalfEdge leftEdge = node.Next.Value as HalfEdge;
HalfEdge rightEdge = node.Previous.Value as HalfEdge;
if ((leftParabola == null) || (rightParabola == null) || (leftParabola.Focus == rightParabola.Focus))
{
return(null);
}
var crosspoint = leftEdge.IntersectionPoint(rightEdge);
if (crosspoint == null)
{
return(null);
}
float distance = Vector2.Distance(crosspoint, parabola.Focus);
if (crosspoint.y + distance > Ypos)
{
return(null);
}
return(new EdgeEvent(parabola)
{
Order = crosspoint.y + distance
});
}