internal void InvalidateNeighbors(AvlNode <Point> pointPrevious, AvlNode <Point> pointNew, AvlNode <Point> pointNext)
{
bool invalidPoint;
if (pointPrevious != null)
{
AvlNode <Point> previousPrevious = pointPrevious.GetPreviousNode();
for (; ;)
{
if (previousPrevious == null)
{
break;
}
invalidPoint = !IsPointToTheRightOfOthers(previousPrevious.Item, pointNew.Item, pointPrevious.Item);
if (!invalidPoint)
{
break;
}
Point ptPrevPrev = previousPrevious.Item;
RemoveNode(pointPrevious);
pointPrevious = this.GetNode(ptPrevPrev);
previousPrevious = pointPrevious.GetPreviousNode();
}
}
// Invalidate next(s)
if (pointNext != null)
{
AvlNode <Point> nextNext = pointNext.GetNextNode();
for (; ;)
{
if (nextNext == null)
{
break;
}
invalidPoint = !IsPointToTheRightOfOthers(pointNew.Item, nextNext.Item, pointNext.Item);
if (!invalidPoint)
{
break;
}
Point ptNextNext = nextNext.Item;
RemoveNode(pointNext);
pointNext = GetNode(ptNextNext);
nextNext = pointNext.GetNextNode();
}
}
}
internal override EnumConvexHullPoint ProcessPoint(ref PolygonPoint point)
{
CurrentNode = Root;
AvlNode <PolygonPoint> currentPrevious = null;
AvlNode <PolygonPoint> currentNext = null;
while (CurrentNode != null)
{
if (CanQuickReject(ref point, ref CurrentNode.Item))
{
return(EnumConvexHullPoint.NotConvexHullPoint);
}
var insertionSide = Side.Unknown;
if (point.Pos.X > CurrentNode.Item.Pos.X)
{
if (CurrentNode.Right != null)
{
CurrentNode = CurrentNode.Right;
continue;
}
currentNext = CurrentNode.GetNextNode();
if (CanQuickReject(ref point, ref currentNext.Item))
{
return(EnumConvexHullPoint.NotConvexHullPoint);
}
if (!IsPointToTheRightOfOthers(CurrentNode.Item, currentNext.Item, point))
{
return(EnumConvexHullPoint.NotConvexHullPoint);
}
insertionSide = Side.Right;
}
else if (point.Pos.X < CurrentNode.Item.Pos.X)
{
if (CurrentNode.Left != null)
{
CurrentNode = CurrentNode.Left;
continue;
}
currentPrevious = CurrentNode.GetPreviousNode();
if (CanQuickReject(ref point, ref currentPrevious.Item))
{
return(EnumConvexHullPoint.NotConvexHullPoint);
}
if (!IsPointToTheRightOfOthers(currentPrevious.Item, CurrentNode.Item, point))
{
return(EnumConvexHullPoint.NotConvexHullPoint);
}
insertionSide = Side.Left;
}
else
{
if (point.Pos.Y >= CurrentNode.Item.Pos.Y)
{
if (point.Pos.Y == CurrentNode.Item.Pos.Y)
{
return(EnumConvexHullPoint.AlreadyExists);
}
return(EnumConvexHullPoint.NotConvexHullPoint); // invalid point
}
// Replace CurrentNode point with point
CurrentNode.Item = point;
InvalidateNeighbors(CurrentNode.GetPreviousNode(), CurrentNode, CurrentNode.GetNextNode());
return(EnumConvexHullPoint.ConvexHullPoint);
}
//We should insert the point
// Try to optimize and verify if can replace a node instead insertion to minimize tree balancing
if (insertionSide == Side.Right)
{
currentPrevious = CurrentNode.GetPreviousNode();
if (currentPrevious != null && !IsPointToTheRightOfOthers(currentPrevious.Item, point, CurrentNode.Item))
{
CurrentNode.Item = point;
InvalidateNeighbors(currentPrevious, CurrentNode, currentNext);
return(EnumConvexHullPoint.ConvexHullPoint);
}
var nextNext = currentNext.GetNextNode();
if (nextNext != null && !IsPointToTheRightOfOthers(point, nextNext.Item, currentNext.Item))
{
currentNext.Item = point;
InvalidateNeighbors(null, currentNext, nextNext);
return(EnumConvexHullPoint.ConvexHullPoint);
}
}
else // Left
{
currentNext = CurrentNode.GetNextNode();
if (currentNext != null && !IsPointToTheRightOfOthers(point, currentNext.Item, CurrentNode.Item))
{
CurrentNode.Item = point;
InvalidateNeighbors(currentPrevious, CurrentNode, currentNext);
return(EnumConvexHullPoint.ConvexHullPoint);
}
var previousPrevious = currentPrevious.GetPreviousNode();
if (previousPrevious != null && !IsPointToTheRightOfOthers(previousPrevious.Item, point, currentPrevious.Item))
{
currentPrevious.Item = point;
InvalidateNeighbors(previousPrevious, currentPrevious, null);
return(EnumConvexHullPoint.ConvexHullPoint);
}
}
// Should insert but no invalidation is required. (That's why we need to insert... can't replace an adjacent neightbor)
AvlNode <PolygonPoint> newNode = new AvlNode <PolygonPoint>();
if (insertionSide == Side.Right)
{
newNode.Parent = CurrentNode;
newNode.Item = point;
CurrentNode.Right = newNode;
this.AddBalance(newNode.Parent, -1);
}
else // Left
{
newNode.Parent = CurrentNode;
newNode.Item = point;
CurrentNode.Left = newNode;
this.AddBalance(newNode.Parent, 1);
}
return(EnumConvexHullPoint.ConvexHullPoint);
}
return(EnumConvexHullPoint.NotConvexHullPoint);
}
// ******************************************************************
/// <summary>
/// Iterate over each points to see if we can add it has a ConvexHull point.
/// It is specific by Quadrant to improve efficiency.
/// </summary>
protected override void ProcessQuadrantSpecific()
{
// Main Loop to extract ConvexHullPoints
foreach (Point point in ListOfPoint)
{
if (!IsGoodQuadrantForPoint(point))
{
continue;
}
CurrentNode = Root;
AvlNode <Point> currentPrevious = null;
AvlNode <Point> currentNext = null;
// Debug.Assert(FirstPoint == GetFirstItem() && LastPoint == GetLastItem());
while (CurrentNode != null)
{
if (CanQuickReject(point, CurrentNode.Item))
{
break;
}
var insertionSide = Side.Unknown;
if (point.X > CurrentNode.Item.X)
{
if (CurrentNode.Right != null)
{
CurrentNode = CurrentNode.Right;
continue;
}
currentNext = CurrentNode.GetNextNode();
if (CanQuickReject(point, currentNext.Item))
{
break;
}
if (!IsPointToTheRightOfOthers(CurrentNode.Item, currentNext.Item, point))
{
break;
}
if (CurrentNode.Item == point) // Ensure to have no duplicate
{
continue;
}
insertionSide = Side.Right;
}
else if (point.X < CurrentNode.Item.X)
{
if (CurrentNode.Left != null)
{
CurrentNode = CurrentNode.Left;
continue;
}
currentPrevious = CurrentNode.GetPreviousNode();
if (CanQuickReject(point, currentPrevious.Item))
{
break;
}
if (!IsPointToTheRightOfOthers(currentPrevious.Item, CurrentNode.Item, point))
{
break;
}
if (CurrentNode.Item == point) // Ensure to have no duplicate
{
continue;
}
insertionSide = Side.Left;
}
else
{
if (point.Y >= CurrentNode.Item.Y)
{
break; // invalid point
}
// Replace CurrentNode point with point
// Debug.Assert(CurrentNode.Parent == null || !point.Equals(CurrentNode.Parent.Item));
CurrentNode.Item = point;
InvalidateNeighbors(CurrentNode.GetPreviousNode(), CurrentNode, CurrentNode.GetNextNode());
break;
}
//We should insert the point
// Try to optimize and verify if can replace a node instead insertion to minimize tree balancing
if (insertionSide == Side.Right)
{
currentPrevious = CurrentNode.GetPreviousNode();
if (currentPrevious != null && !IsPointToTheRightOfOthers(currentPrevious.Item, point, CurrentNode.Item))
{
// DebugEnsureTreeIsValid();
// Debug.Assert(CurrentNode.Item != FirstPoint && CurrentNode.Item != LastPoint);
// Debug.Assert(CurrentNode.Parent == null || !point.Equals(CurrentNode.Parent.Item));
CurrentNode.Item = point;
InvalidateNeighbors(currentPrevious, CurrentNode, currentNext);
// DebugEnsureTreeIsValid();
break;
}
var nextNext = currentNext.GetNextNode();
if (nextNext != null && !IsPointToTheRightOfOthers(point, nextNext.Item, currentNext.Item))
{
// DebugEnsureTreeIsValid();
// Debug.Assert(currentNext.Item != FirstPoint && currentNext.Item != LastPoint);
// Debug.Assert(CurrentNode.Parent == null || !point.Equals(CurrentNode.Parent.Item));
currentNext.Item = point;
InvalidateNeighbors(null, currentNext, nextNext);
// DebugEnsureTreeIsValid();
break;
}
}
else // Left
{
currentNext = CurrentNode.GetNextNode();
if (currentNext != null && !IsPointToTheRightOfOthers(point, currentNext.Item, CurrentNode.Item))
{
// DebugEnsureTreeIsValid();
// Debug.Assert(CurrentNode.Item != FirstPoint && CurrentNode.Item != LastPoint);
// Debug.Assert(CurrentNode.Parent == null || !point.Equals(CurrentNode.Parent.Item));
CurrentNode.Item = point;
InvalidateNeighbors(currentPrevious, CurrentNode, currentNext);
// DebugEnsureTreeIsValid();
break;
}
var previousPrevious = currentPrevious.GetPreviousNode();
if (previousPrevious != null && !IsPointToTheRightOfOthers(previousPrevious.Item, point, currentPrevious.Item))
{
// DebugEnsureTreeIsValid();
// Debug.Assert(currentPrevious.Item != FirstPoint && currentPrevious.Item != LastPoint);
// Debug.Assert(CurrentNode.Parent == null || !point.Equals(CurrentNode.Parent.Item));
currentPrevious.Item = point;
InvalidateNeighbors(previousPrevious, currentPrevious, null);
// DebugEnsureTreeIsValid();
break;
}
}
// Should insert but no invalidation is required. (That's why we need to insert... can't replace an adjacent neightbor)
AvlNode <Point> newNode = new AvlNode <Point>();
if (insertionSide == Side.Right)
{
newNode.Parent = CurrentNode;
newNode.Item = point;
CurrentNode.Right = newNode;
this.AddBalance(newNode.Parent, -1);
}
else // Left
{
newNode.Parent = CurrentNode;
newNode.Item = point;
CurrentNode.Left = newNode;
this.AddBalance(newNode.Parent, 1);
}
// DebugEnsureTreeIsValid();
break;
}
// Debug.Assert(FirstPoint == GetFirstItem() && LastPoint == GetLastItem());
}
// Dump2("", Name);
}