protected void InvalidateNeighbors(AvlNode <MutablePoint> pointPrevious, AvlNode <MutablePoint> pointNew, AvlNode <MutablePoint> pointNext)
{
bool invalidPoint;
if (pointPrevious != null)
{
AvlNode <MutablePoint> previousPrevious = pointPrevious.GetPreviousNode();
for (; ;)
{
if (previousPrevious == null)
{
break;
}
invalidPoint = !this.IsPointToTheRightOfOthers(previousPrevious.Item, pointNew.Item, pointPrevious.Item);
if (!invalidPoint)
{
break;
}
MutablePoint pointPrevPrev = previousPrevious.Item;
this.RemoveNode(pointPrevious);
pointPrevious = this.GetNode(pointPrevPrev);
previousPrevious = pointPrevious.GetPreviousNode();
}
}
// Invalidate next(s)
if (pointNext != null)
{
AvlNode <MutablePoint> nextNext = pointNext.GetNextNode();
for (; ;)
{
if (nextNext == null)
{
break;
}
invalidPoint = !this.IsPointToTheRightOfOthers(pointNew.Item, nextNext.Item, pointNext.Item);
if (!invalidPoint)
{
break;
}
MutablePoint pointNextNext = nextNext.Item;
this.RemoveNode(pointNext);
pointNext = this.GetNode(pointNextNext);
nextNext = pointNext.GetNextNode();
}
}
}
/// <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>
/// <param name="point">a point</param>
//// [MethodImpl(MethodImplOptions.AggressiveInlining)]
internal override void ProcessPoint(ref MutablePoint point)
{
this.CurrentNode = this.Root;
AvlNode <MutablePoint> currentPrevious = null;
AvlNode <MutablePoint> currentNext = null;
while (this.CurrentNode != null)
{
var insertionSide = Side.Unknown;
if (point.X > this.CurrentNode.Item.X)
{
if (this.CurrentNode.Left != null)
{
this.CurrentNode = this.CurrentNode.Left;
continue;
}
currentPrevious = this.CurrentNode.GetPreviousNode();
if (CanQuickReject(ref point, ref currentPrevious.Item))
{
return;
}
if (!this.IsPointToTheRightOfOthers(currentPrevious.Item, this.CurrentNode.Item, point))
{
return;
}
// Ensure to have no duplicate
if (this.CurrentNode.Item == point)
{
return;
}
insertionSide = Side.Left;
}
else if (point.X < this.CurrentNode.Item.X)
{
if (this.CurrentNode.Right != null)
{
this.CurrentNode = this.CurrentNode.Right;
continue;
}
currentNext = this.CurrentNode.GetNextNode();
if (CanQuickReject(ref point, ref currentNext.Item))
{
return;
}
if (!this.IsPointToTheRightOfOthers(this.CurrentNode.Item, currentNext.Item, point))
{
return;
}
// Ensure to have no duplicate
if (this.CurrentNode.Item == point)
{
continue;
}
insertionSide = Side.Right;
}
else
{
if (point.Y <= this.CurrentNode.Item.Y)
{
return; // invalid point
}
// Replace CurrentNode point with point
this.CurrentNode.Item = point;
this.InvalidateNeighbors(this.CurrentNode.GetPreviousNode(), this.CurrentNode, this.CurrentNode.GetNextNode());
return;
}
// 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 = this.CurrentNode.GetPreviousNode();
if (currentPrevious != null && !this.IsPointToTheRightOfOthers(currentPrevious.Item, point, this.CurrentNode.Item))
{
this.CurrentNode.Item = point;
this.InvalidateNeighbors(currentPrevious, this.CurrentNode, currentNext);
return;
}
var nextNext = currentNext.GetNextNode();
if (nextNext != null && !this.IsPointToTheRightOfOthers(point, nextNext.Item, currentNext.Item))
{
currentNext.Item = point;
this.InvalidateNeighbors(null, currentNext, nextNext);
return;
}
}
else
{
// Left
currentNext = this.CurrentNode.GetNextNode();
if (currentNext != null && !this.IsPointToTheRightOfOthers(point, currentNext.Item, this.CurrentNode.Item))
{
this.CurrentNode.Item = point;
this.InvalidateNeighbors(currentPrevious, this.CurrentNode, currentNext);
return;
}
var previousPrevious = currentPrevious.GetPreviousNode();
if (previousPrevious != null && !this.IsPointToTheRightOfOthers(previousPrevious.Item, point, currentPrevious.Item))
{
currentPrevious.Item = point;
this.InvalidateNeighbors(previousPrevious, currentPrevious, null);
return;
}
}
// Should insert but no invalidation is required. (That's why we need to insert... can't replace an adjacent neighbor)
AvlNode <MutablePoint> newNode = new AvlNode <MutablePoint>();
if (insertionSide == Side.Right)
{
newNode.Parent = this.CurrentNode;
newNode.Item = point;
this.CurrentNode.Right = newNode;
this.AddBalance(newNode.Parent, -1);
}
else
{
// Left
newNode.Parent = this.CurrentNode;
newNode.Item = point;
this.CurrentNode.Left = newNode;
this.AddBalance(newNode.Parent, 1);
}
return;
}
}