void HandleLeftEvent(SweepEvent currentEvent)
{
AVLNode <SweepEvent> position = sweepLineEvents.Insert(currentEvent); // the line segment must be inserted into S
currentEvent.positionInS = position;
prev = position.GetPredecessor();
next = position.GetSuccessor();
// Compute the inside and inOut flags
if (prev == null)
{
currentEvent.Inside = false;
currentEvent.InOut = false;
}
else if (prev.Value.Type != EdgeType.NORMAL)
{
if (prev.Value == sweepLineEvents.GetMin()) // currentEvent overlaps with prev // JUST GET! NOT POP!
{
currentEvent.Inside = true; // it is not relevant to set true or false
currentEvent.InOut = false;
}
else // the previous two line segments in S are overlapping line segments
{
prevPrev = prev.GetPredecessor();
if (prev.Value.OwningPolygon == currentEvent.OwningPolygon)
{
currentEvent.InOut = !prev.Value.InOut;
currentEvent.Inside = !prevPrev.Value.InOut;
}
else
{
currentEvent.InOut = !prevPrev.Value.InOut;
currentEvent.Inside = !prev.Value.InOut;
}
}
}
else if (currentEvent.OwningPolygon == prev.Value.OwningPolygon) // edges of same polygon
{
currentEvent.Inside = prev.Value.Inside;
currentEvent.InOut = !prev.Value.InOut;
}
else // edges of different polygons
{
currentEvent.Inside = !prev.Value.InOut;
currentEvent.InOut = prev.Value.Inside;
}
AddDebugEdge(currentEvent);
if (next != null)
{
PossibleIntersection(currentEvent, next.Value);
}
if (prev != null)
{
PossibleIntersection(prev.Value, currentEvent);
}
}
void HandleRightEvent(OperationType ot, SweepEvent currentEvent)
{
// the left end/part of the current SweepEvent must be removed from sweepLineEvents
left = currentEvent.Other.positionInS;
next = left.GetSuccessor();
prev = left.GetPredecessor();
// Check if the line segment belongs to the Boolean operation
switch (currentEvent.Type)
{
case EdgeType.NORMAL:
switch (ot)
{
case OperationType.INTERSECTION: if (currentEvent.Other.Inside)
{
connector.Add(currentEvent.CreateEdge());
}
break;
case OperationType.UNION: if (!currentEvent.Other.Inside)
{
connector.Add(currentEvent.CreateEdge());
}
break;
case OperationType.DIFFERENCE: if ((currentEvent.OwningPolygon == (int)Operand.SUBJECT && !currentEvent.Other.Inside) ||
(currentEvent.OwningPolygon == (int)Operand.CLIPPER && currentEvent.Other.Inside))
{
connector.Add(currentEvent.CreateEdge());
}
break;
case OperationType.XOR: connector.Add(currentEvent.CreateEdge()); break;
}
break;
case EdgeType.SAME_TRANSITION: if (ot == OperationType.INTERSECTION || ot == OperationType.UNION)
{
connector.Add(currentEvent.CreateEdge());
}
break;
case EdgeType.DIFFERENT_TRANSITION: if (ot == OperationType.DIFFERENCE)
{
connector.Add(currentEvent.CreateEdge());
}
break;
}
AddDebugEdge(currentEvent);
sweepLineEvents.RemoveAt(left);
if (next != null && prev != null)
{
PossibleIntersection(prev.Value, next.Value);
}
}
