////////////////////////////////////////////////////////////////////////////////////////////////////
/// <summary> Insert a new polygon arising from a site event. </summary>
/// <remarks> Darrellp, 2/19/2011. </remarks>
/// <param name="evt"> Site event causing the new polygon. </param>
/// <param name="evq"> Event queue. </param>
////////////////////////////////////////////////////////////////////////////////////////////////////
internal void PolyInsertNode(SiteEvent evt, EventQueue evq)
{
// If there's no tree yet
if (NdRoot == null)
{
// Create a leaf node and make it the tree root
NdRoot = new LeafNode(evt.Poly);
return;
}
// Get the parabola above this site and the parabolas to its left and right
var lfn = LfnSearchNode(evt.Pt.X, evt.Pt.Y);
var lfnLeft = lfn.LeftAdjacentLeaf;
var lfnRight = lfn.RightAdjacentLeaf;
// Remove the circle event associated with the parabola we intersect
//
// We are inserting ourselves into this parabola which means it's old circle event is defunct
// so toss it.
lfn.DeleteAssociatedCircleEvent(evq);
// Create a new subtree to hold the new leaf node
var innSubRoot = NdCreateInsertionSubtree(lfn, evt);
// If the root node is a leaf
if (NdRoot.IsLeaf)
{
// Replace it with the new inner node we just created
NdRoot = innSubRoot;
}
// TODO: Rebalancing the tree
//Rebalance(innSubRoot);
// For every circle event
//
// Remove any circle events that this generator is inside since it will be closer to the center
// of the circle than any of the three points which lie on the circle
// TODO: Is there a good way to optimize this?
var lln = evq.CircleEvents.First;
while (lln != null)
{
var cevt = lln.Value;
var llnNext = lln.Next;
if (cevt.Contains(evt.Pt))
{
// Delete the circle event
evq.CircleEvents.Remove(lln);
cevt.LinkedListNode = null;
}
lln = llnNext;
}
// Create any circle events which this site causes
CreateCircleEventsFromSiteEvent(lfnLeft, lfnRight, evt.Pt.Y, evq);
}
////////////////////////////////////////////////////////////////////////////////////////////////////
/// <summary> Insert a new LeafNode into the tree. </summary>
/// <remarks> Darrellp, 2/19/2011. </remarks>
/// <param name="lfn"> Place to put the new leaf node. </param>
/// <param name="evt"> The event to insert. </param>
/// <returns> . </returns>
////////////////////////////////////////////////////////////////////////////////////////////////////
private static InternalNode NdCreateInsertionSubtree(LeafNode lfn, SiteEvent evt)
{
// Initialize locals
var innParent = lfn.NdParent;
var lfnNewParabola = new LeafNode(evt.Poly);
var innSubRoot = new InternalNode(evt.Poly, lfn.Poly);
var fLeftChild = true;
// If this isn't on the root node, shuffle things around a bit
if (innParent != null)
{
fLeftChild = lfn.IsLeftChild;
lfn.SnipFromParent();
if (fLeftChild)
{
innParent.LeftChild = innSubRoot;
}
else
{
innParent.RightChild = innSubRoot;
}
}
// Watch for the odd corner case of the top n generators having the same y coordinate. See comments
// on NdInsertAtSameY().
if (Geometry2D.FCloseEnough(evt.Pt.Y, lfn.Poly.VoronoiPoint.Y))
{
NdInsertAtSameY(lfn, lfnNewParabola, innParent, innSubRoot, fLeftChild);
}
else
{
InsertAtDifferentY(lfn, lfnNewParabola, innSubRoot);
}
return(innSubRoot);
}