public int CompareTo(IntersectionSweepEvent other)
{
if (Equals(other))
{
return(0);
}
if (Point.x > other.Point.x)
{
return(1);
}
if (Point.x < other.Point.x)
{
return(-1);
}
if (!Point.y.Equals(other.Point.y))
{
return(Point.y > other.Point.y ? 1 : -1);
}
if (IsStart != other.IsStart)
{
return(IsStart ? 1 : -1);
}
if (Segment != other.Segment)
{
return(Below(other.OtherEvent.Point) ? -1 : 1);
}
return(0);
}
public void AddEvents(LineSegment segment, List <IntersectionSweepEvent> events)
{
Vector2 point1 = segment.Point1;
Vector2 point2 = segment.Point2;
var ev1 = new IntersectionSweepEvent(point1, false, false, segment, null as IntersectionSweepEvent);
var ev2 = new IntersectionSweepEvent(point2, false, false, segment, ev1);
ev1.OtherEvent = ev2;
if (point1.Equals(point2))
{
return;
}
if (ev1.CompareTo(ev2) < 1)
{
ev1.IsStart = true;
ev2.IsEnd = true;
}
else
{
ev1.IsEnd = true;
ev2.IsStart = true;
}
events.Add(ev1);
events.Add(ev2);
}
public IntersectionSweepEvent(Vector2 point, bool isStart, bool isEnd, LineSegment segment,
IntersectionSweepEvent otherEvent)
{
Point = new Vector2D(point);
IsStart = isStart;
IsEnd = isEnd;
Segment = segment;
OtherEvent = otherEvent;
}
public int CompareTo(IntersectionStatusItem other)
{
if (Equals(other))
{
return(0);
}
IntersectionSweepEvent ev = SweepEvent;
IntersectionSweepEvent otherEv = other.SweepEvent;
if (ev.Equals(otherEv))
{
return(0);
}
if (MathUtil.SignedArea(ev.Point, ev.OtherEvent.Point, otherEv.Point) != 0 ||
MathUtil.SignedArea(ev.Point, ev.OtherEvent.Point, otherEv.OtherEvent.Point) != 0)
{
if (ev.Point.Equals(otherEv.Point))
{
return(ev.Below(otherEv.OtherEvent.Point) ? -1 : 1);
}
if (ev.Point.x.Equals(otherEv.Point.x))
{
return(ev.Point.y < otherEv.Point.y ? -1 : 1);
}
if (ev.CompareTo(otherEv) == 1)
{
return(!otherEv.Below(ev.Point) ? -1 : 1);
}
return(ev.Below(otherEv.Point) ? -1 : 1);
}
if (ev.Point.Equals(otherEv.Point) && ev.OtherEvent.Point.Equals(otherEv.OtherEvent.Point))
{
return(0);
}
return(ev.CompareTo(otherEv) == 1 ? 1 : -1);
}
public bool Equals(IntersectionSweepEvent other)
{
return(this == other);
}
public void HandleEvent(IBST <IntersectionSweepEvent> events, IBST <IntersectionStatusItem> status,
IntersectionSweepEvent ev)
{
if (ev.IsStart)
{
ev.StatusItem = new IntersectionStatusItem(ev);
status.Insert(ev.StatusItem);
IntersectionStatusItem prev, next;
bool prevFound = status.FindNextSmallest(ev.StatusItem, out prev);
bool nextFound = status.FindNextBiggest(ev.StatusItem, out next);
if (prevFound)
{
LineSegment otherSegment = prev.SweepEvent.Segment;
Vector2? intersection = ev.Segment.IntersectProper(otherSegment);
if (intersection != null)
{
events.Insert(new IntersectionSweepEvent(intersection.Value, false, false,
ev.Segment, otherSegment));
}
}
if (nextFound)
{
LineSegment otherSegment = next.SweepEvent.Segment;
Vector2? intersection = ev.Segment.IntersectProper(otherSegment);
if (intersection != null)
{
events.Insert(new IntersectionSweepEvent(intersection.Value, false, false,
ev.Segment, otherSegment));
}
}
}
else if (ev.IsEnd)
{
ev = ev.OtherEvent;
if (ev.StatusItem == null)
{
return;
}
IntersectionStatusItem prev, next;
bool prevFound = status.FindNextSmallest(ev.StatusItem, out prev);
bool nextFound = status.FindNextBiggest(ev.StatusItem, out next);
status.Delete(ev.StatusItem);
if (nextFound && prevFound)
{
LineSegment segment = prev.SweepEvent.Segment;
LineSegment otherSegment = next.SweepEvent.Segment;
Vector2? intersection = segment.IntersectProper(otherSegment);
if (intersection != null)
{
events.Insert(new IntersectionSweepEvent(intersection.Value, false, false,
segment, otherSegment));
}
}
}
else if (ev.IsIntersection)
{
// stop on first intersection
intersected = new List <Edge>
{
new Edge(new Vertex(ev.Segment.Point1), new Vertex(ev.Segment.Point2)),
new Edge(new Vertex(ev.OtherSegment.Point1), new Vertex(ev.OtherSegment.Point2))
};
events.Clear();
status.Clear();
}
else
{
throw new Exception("Invalid event type");
}
}
public IntersectionStatusItem(IntersectionSweepEvent sweepEvent)
{
SweepEvent = sweepEvent;
}