/// <summary>
/// Initialize the event queue with the given items.
/// </summary>
/// <param name="items"></param>
/// <returns></returns>
public IBST <ISweepEvent <T> > InitializeEvents(IEnumerable <ISweepEvent <T> > items)
{
Events.Clear();
foreach (var item in items)
{
Events.Insert(item);
}
return(Events);
}
/// <summary>
/// Initialize the status tree with the given items.
/// </summary>
/// <param name="items"></param>
/// <returns></returns>
public IBST <T> InitializeStatus(IEnumerable <T> items)
{
Status.Clear();
foreach (var item in items)
{
Status.Insert(item);
}
return(Status);
}
/// <summary>
/// Initialize the event queue with the given items.
/// </summary>
/// <param name="items"></param>
/// <returns></returns>
public IBST <E> InitializeEvents(IEnumerable <E> items)
{
Events.Clear();
foreach (var item in items)
{
if (!Events.Insert(item))
{
throw new ArgumentException(string.Format("Failed to insert event {0}", item));
}
}
return(Events);
}
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");
}
}