/// <summary>
/// Creates a new Voronoi Graph given a set of Points
/// </summary>
/// <param name="Datapoints">Data points to base the Voronoi Graph around</param>
/// <returns></returns>
public static VoronoiGraph GenerateGraph(IEnumerable Datapoints)
{
BinaryPriorityQueue PQ = new BinaryPriorityQueue();
Hashtable CurrentCircles = new Hashtable();
VoronoiGraph Graph = new VoronoiGraph();
VNode RootNode = null;
foreach (Vector2 V in Datapoints)
{
PQ.Push(new VDataEvent(V));
}
while (PQ.Count > 0)
{
VEvent VE = PQ.Pop() as VEvent;
VDataNode[] CircleCheckList;
if (VE is VDataEvent)
{
RootNode = VNode.ProcessDataEvent(VE as VDataEvent, RootNode, Graph, VE.Y, out CircleCheckList);
}
else if (VE is VCircleEvent)
{
CurrentCircles.Remove(((VCircleEvent)VE).NodeN);
if (!((VCircleEvent)VE).Valid)
continue;
RootNode = VNode.ProcessCircleEvent(VE as VCircleEvent, RootNode, Graph, VE.Y, out CircleCheckList);
}
else throw new Exception("Got event of type " + VE.GetType().ToString() + "!");
foreach (VDataNode VD in CircleCheckList)
{
if (CurrentCircles.ContainsKey(VD))
{
((VCircleEvent)CurrentCircles[VD]).Valid = false;
CurrentCircles.Remove(VD);
}
VCircleEvent VCE = VNode.CircleCheckDataNode(VD, VE.Y);
if (VCE != null)
{
PQ.Push(VCE);
CurrentCircles[VD] = VCE;
}
}
if (VE is VDataEvent)
{
Vector2 DP = ((VDataEvent)VE).DataPoint;
foreach (VCircleEvent VCE in CurrentCircles.Values)
{
if (Vector2.Distance(DP, VCE.Center) < VCE.Y - VCE.Center.y && Math.Abs(Vector2.Distance(DP, VCE.Center) - (VCE.Y - VCE.Center.y)) > 1e-10)
VCE.Valid = false;
}
}
}
return Graph;
}
/// <summary>
/// Will return the new root (unchanged except in start-up)
/// </summary>
public static VNode ProcessDataEvent(VDataEvent e, VNode Root, VoronoiGraph VG, float ys, out VDataNode[] CircleCheckList)
{
if (Root == null)
{
Root = new VDataNode(e.DataPoint);
CircleCheckList = new VDataNode[] { (VDataNode)Root };
return Root;
}
//1. Find the node to be replaced
VNode C = VNode.FindDataNode(Root, ys, e.DataPoint.x);
//2. Create the subtree (ONE Edge, but two VEdgeNodes)
VoronoiEdge VE = new VoronoiEdge();
VE.Left = ((VDataNode)C).DataPoint;
VE.Right = e.DataPoint;
VE.VVertexA = Fortune.VVUnkown;
VE.VVertexB = Fortune.VVUnkown;
VG.Edges.Add(VE);
VNode SubRoot;
if (Math.Abs(VE.Left.y - VE.Right.y) < 1e-10)
{
if (VE.Left.x < VE.Right.x)
{
SubRoot = new VEdgeNode(VE, false);
SubRoot.Left = new VDataNode(VE.Left);
SubRoot.Right = new VDataNode(VE.Right);
}
else
{
SubRoot = new VEdgeNode(VE, true);
SubRoot.Left = new VDataNode(VE.Right);
SubRoot.Right = new VDataNode(VE.Left);
}
CircleCheckList = new VDataNode[] { (VDataNode)SubRoot.Left, (VDataNode)SubRoot.Right };
}
else
{
SubRoot = new VEdgeNode(VE, false);
SubRoot.Left = new VDataNode(VE.Left);
SubRoot.Right = new VEdgeNode(VE, true);
SubRoot.Right.Left = new VDataNode(VE.Right);
SubRoot.Right.Right = new VDataNode(VE.Left);
CircleCheckList = new VDataNode[] { (VDataNode)SubRoot.Left, (VDataNode)SubRoot.Right.Left, (VDataNode)SubRoot.Right.Right };
}
//3. Apply subtree
if (C.Parent == null)
return SubRoot;
C.Parent.Replace(C, SubRoot);
return Root;
}
public static VNode ProcessCircleEvent(VCircleEvent e, VNode Root, VoronoiGraph VG, float ys, out VDataNode[] CircleCheckList)
{
VDataNode a, b, c;
VEdgeNode eu, eo;
b = e.NodeN;
a = VNode.LeftDataNode(b);
c = VNode.RightDataNode(b);
if (a == null || b.Parent == null || c == null || !a.DataPoint.Equals(e.NodeL.DataPoint) || !c.DataPoint.Equals(e.NodeR.DataPoint))
{
CircleCheckList = new VDataNode[] { };
return Root; // Abbruch da sich der Graph verändert hat
}
eu = (VEdgeNode)b.Parent;
CircleCheckList = new VDataNode[] { a, c };
//1. Create the new Vertex
Vector2 VNew = new Vector2(e.Center.x, e.Center.y);
// VNew[0] = Fortune.ParabolicCut(a.DataPoint[0],a.DataPoint[1],c.DataPoint[0],c.DataPoint[1],ys);
// VNew[1] = (ys + a.DataPoint[1])/2 - 1/(2*(ys-a.DataPoint[1]))*(VNew[0]-a.DataPoint[0])*(VNew[0]-a.DataPoint[0]);
VG.Vertices.Add(VNew);
//2. Find out if a or c are in a distand part of the tree (the other is then b's sibling) and assign the new vertex
if (eu.Left == b) // c is sibling
{
eo = VNode.EdgeToRightDataNode(a);
// replace eu by eu's Right
eu.Parent.Replace(eu, eu.Right);
}
else // a is sibling
{
eo = VNode.EdgeToRightDataNode(b);
// replace eu by eu's Left
eu.Parent.Replace(eu, eu.Left);
}
eu.Edge.AddVertex(VNew);
// ///////////////////// uncertain
// if(eo==eu)
// return Root;
// /////////////////////
eo.Edge.AddVertex(VNew);
//2. Replace eo by new Edge
VoronoiEdge VE = new VoronoiEdge();
VE.Left = a.DataPoint;
VE.Right = c.DataPoint;
VE.AddVertex(VNew);
VG.Edges.Add(VE);
VEdgeNode VEN = new VEdgeNode(VE, false);
VEN.Left = eo.Left;
VEN.Right = eo.Right;
if (eo.Parent == null)
return VEN;
eo.Parent.Replace(eo, VEN);
return Root;
}