public static Vertex Intersect(HalfEdge he0, HalfEdge he1)
{
var edge0 = he0.Edge;
var edge1 = he1.Edge;
if (edge0 == null || edge1 == null) return null;
if (edge0.RightSite == edge1.RightSite) return null;
var determinant = edge0.A*edge1.B - edge0.B*edge1.A;
if (-1.0e-10 < determinant && determinant < 1.0e-10) {
return null;
}
var intersectionX = (edge0.C*edge1.B - edge1.C*edge0.B)/determinant;
var intersectionY = (edge1.C*edge0.A - edge0.C * edge1.A)/determinant;
HalfEdge halfEdge;
Edge edge;
if (Voronoi.CompareByYThenX(edge0.RightSite, edge1.RightSite) < 0) {
halfEdge = he0;
edge = edge0;
} else {
halfEdge = he1;
edge = edge1;
}
var rightOfSite = intersectionX >= edge.RightSite.X;
if ((rightOfSite && halfEdge.LeftRight == LR.Left) || (!rightOfSite && halfEdge.LeftRight == LR.Right)) {
return null;
}
return Create(intersectionX, intersectionY);
}
public void Remove(HalfEdge halfEdge)
{
var removalBucket = Bucket(halfEdge);
if (halfEdge.Vertex != null) {
var previous = _hash[removalBucket];
while (previous.NextInPriorityQueue != halfEdge) {
previous = previous.NextInPriorityQueue;
}
previous.NextInPriorityQueue = halfEdge.NextInPriorityQueue;
_count--;
}
}
public void Insert(HalfEdge halfEdge)
{
var insertionBucket = Bucket(halfEdge);
if (insertionBucket < _minBucket) {
_minBucket = insertionBucket;
}
var previous = _hash[insertionBucket];
HalfEdge next;
while ((next = previous.NextInPriorityQueue) != null && (halfEdge.YStar > next.YStar && halfEdge.Vertex.X > next.Vertex.X)) {
previous = next;
}
halfEdge.NextInPriorityQueue = previous.NextInPriorityQueue;
previous.NextInPriorityQueue = halfEdge;
++_count;
}
public EdgeList(float xmin, float deltax, int sqrtNSites)
{
_xmin = xmin;
_deltaX = deltax;
_hashSize = 2 * sqrtNSites;
_hash = new List<HalfEdge>(new HalfEdge[_hashSize]);
LeftEnd = new HalfEdge();
RightEnd = new HalfEdge();
LeftEnd.EdgeListLeftNeighbor = null;
LeftEnd.EdgeListRightNeighbor = RightEnd;
RightEnd.EdgeListLeftNeighbor = LeftEnd;
RightEnd.EdgeListRightNeighbor = null;
_hash[0] = LeftEnd;
_hash[_hashSize - 1] = RightEnd;
}
private static Site RightRegion(HalfEdge he)
{
var edge = he.Edge;
return edge == null ? null : edge.Site(LR.Other(he.LeftRight));
}
private void FortunesAlgorithm()
{
var dataBounds = _sites.GetSiteBounds();
var sqrtNSites = (int)Math.Sqrt(_sites.Length + 4);
var heap = new HalfEdgePriorityQueue(dataBounds.Top, dataBounds.Height, sqrtNSites);
var edgeList = new EdgeList(dataBounds.Left, dataBounds.Width, sqrtNSites);
var halfEdges = new List<HalfEdge>();
var vertices = new List<Vertex>();
var bottomMostSite = _sites.Next();
var newSite = _sites.Next();
var newIntStar = new Vector2();
for (; ; ) {
if (!heap.Empty) {
newIntStar = heap.Min();
}
if (newSite != null && (heap.Empty || CompareByYThenX(newSite, newIntStar) < 0)) {
Console.WriteLine("smallest: new site " + newSite);
var lbnd = edgeList.EdgeListLeftNeighbor(newSite.Coord);
Console.WriteLine("lbnd: " + lbnd);
var rbnd = lbnd.EdgeListRightNeighbor;
Console.WriteLine("rbnd: " + rbnd);
var bottomSite = RightRegion(lbnd) ?? bottomMostSite;
Console.WriteLine("new site is in region of existing site: " + bottomSite);
var edge = Edge.CreateBisectingEdge(bottomSite, newSite);
Console.WriteLine("new edge: " + edge);
Edges.Add(edge);
var bisector = new HalfEdge(edge, LR.Left);
halfEdges.Add(bisector);
edgeList.Insert(lbnd, bisector);
Vertex vertex = Vertex.Intersect(lbnd, bisector);
if (vertex != null) {
vertices.Add(vertex);
heap.Remove(lbnd);
lbnd.Vertex = vertex;
lbnd.YStar = vertex.Y + newSite.Distance(vertex);
heap.Insert(lbnd);
}
lbnd = bisector;
bisector = new HalfEdge(edge, LR.Right);
halfEdges.Add(bisector);
edgeList.Insert(lbnd, bisector);
vertex = Vertex.Intersect(bisector, rbnd);
if (vertex != null) {
vertices.Add(vertex);
bisector.Vertex = vertex;
bisector.YStar = vertex.Y + newSite.Distance(vertex);
heap.Insert(bisector);
}
newSite = _sites.Next();
} else if (!heap.Empty) {
var lbnd = heap.ExtractMin();
var llbnd = lbnd.EdgeListLeftNeighbor;
var rbnd = lbnd.EdgeListRightNeighbor;
var rrbnd = rbnd.EdgeListRightNeighbor;
var bottomSite = LeftRegion(lbnd) ?? bottomMostSite;
var topSite = RightRegion(rbnd) ?? bottomMostSite;
var v = lbnd.Vertex;
v.SetIndex();
lbnd.Edge.SetVertex(lbnd.LeftRight, v);
rbnd.Edge.SetVertex(rbnd.LeftRight, v);
edgeList.Remove(lbnd);
heap.Remove(rbnd);
edgeList.Remove(rbnd);
var leftRight = LR.Left;
if (bottomSite.Y > topSite.Y) {
var tempSite = bottomSite;
bottomSite = topSite;
topSite = tempSite;
leftRight = LR.Right;
}
var edge = Edge.CreateBisectingEdge(bottomSite, topSite);
Edges.Add(edge);
var bisector = new HalfEdge(edge, leftRight);
halfEdges.Add(bisector);
edgeList.Insert(llbnd, bisector);
edge.SetVertex(LR.Other(leftRight), v);
Vertex vertex;
if ((vertex = Vertex.Intersect(llbnd, bisector)) != null) {
vertices.Add(vertex);
heap.Remove(llbnd);
llbnd.Vertex = vertex;
llbnd.YStar = vertex.Y + bottomSite.Distance(vertex);
heap.Insert(llbnd);
}
if ((vertex = Vertex.Intersect(bisector, rrbnd)) != null) {
vertices.Add(vertex);
bisector.Vertex = vertex;
bisector.YStar = vertex.Y + bottomSite.Distance(vertex);
heap.Insert(bisector);
}
} else {
break;
}
}
halfEdges.Clear();
var nullVerts = Edges.Where(e => e.RightVertex == null || e.LeftVertex == null).ToList();
foreach (var edge in Edges) {
edge.ClipVertices(PlotBounds);
}
vertices.Clear();
}
private void FortunesAlgorithm()
{
var dataBounds = _sites.GetSiteBounds();
var sqrtNSites = (int)Math.Sqrt(_sites.Length + 4);
var heap = new HalfEdgePriorityQueue(dataBounds.Top, dataBounds.Height, sqrtNSites);
var edgeList = new EdgeList(dataBounds.Left, dataBounds.Width, sqrtNSites);
var halfEdges = new List <HalfEdge>();
var vertices = new List <Vertex>();
var bottomMostSite = _sites.Next();
var newSite = _sites.Next();
var newIntStar = new Vector2();
for (; ;)
{
if (!heap.Empty)
{
newIntStar = heap.Min();
}
if (newSite != null && (heap.Empty || CompareByYThenX(newSite, newIntStar) < 0))
{
Console.WriteLine("smallest: new site " + newSite);
var lbnd = edgeList.EdgeListLeftNeighbor(newSite.Coord);
Console.WriteLine("lbnd: " + lbnd);
var rbnd = lbnd.EdgeListRightNeighbor;
Console.WriteLine("rbnd: " + rbnd);
var bottomSite = RightRegion(lbnd) ?? bottomMostSite;
Console.WriteLine("new site is in region of existing site: " + bottomSite);
var edge = Edge.CreateBisectingEdge(bottomSite, newSite);
Console.WriteLine("new edge: " + edge);
Edges.Add(edge);
var bisector = new HalfEdge(edge, LR.Left);
halfEdges.Add(bisector);
edgeList.Insert(lbnd, bisector);
Vertex vertex = Vertex.Intersect(lbnd, bisector);
if (vertex != null)
{
vertices.Add(vertex);
heap.Remove(lbnd);
lbnd.Vertex = vertex;
lbnd.YStar = vertex.Y + newSite.Distance(vertex);
heap.Insert(lbnd);
}
lbnd = bisector;
bisector = new HalfEdge(edge, LR.Right);
halfEdges.Add(bisector);
edgeList.Insert(lbnd, bisector);
vertex = Vertex.Intersect(bisector, rbnd);
if (vertex != null)
{
vertices.Add(vertex);
bisector.Vertex = vertex;
bisector.YStar = vertex.Y + newSite.Distance(vertex);
heap.Insert(bisector);
}
newSite = _sites.Next();
}
else if (!heap.Empty)
{
var lbnd = heap.ExtractMin();
var llbnd = lbnd.EdgeListLeftNeighbor;
var rbnd = lbnd.EdgeListRightNeighbor;
var rrbnd = rbnd.EdgeListRightNeighbor;
var bottomSite = LeftRegion(lbnd) ?? bottomMostSite;
var topSite = RightRegion(rbnd) ?? bottomMostSite;
var v = lbnd.Vertex;
v.SetIndex();
lbnd.Edge.SetVertex(lbnd.LeftRight, v);
rbnd.Edge.SetVertex(rbnd.LeftRight, v);
edgeList.Remove(lbnd);
heap.Remove(rbnd);
edgeList.Remove(rbnd);
var leftRight = LR.Left;
if (bottomSite.Y > topSite.Y)
{
var tempSite = bottomSite;
bottomSite = topSite;
topSite = tempSite;
leftRight = LR.Right;
}
var edge = Edge.CreateBisectingEdge(bottomSite, topSite);
Edges.Add(edge);
var bisector = new HalfEdge(edge, leftRight);
halfEdges.Add(bisector);
edgeList.Insert(llbnd, bisector);
edge.SetVertex(LR.Other(leftRight), v);
Vertex vertex;
if ((vertex = Vertex.Intersect(llbnd, bisector)) != null)
{
vertices.Add(vertex);
heap.Remove(llbnd);
llbnd.Vertex = vertex;
llbnd.YStar = vertex.Y + bottomSite.Distance(vertex);
heap.Insert(llbnd);
}
if ((vertex = Vertex.Intersect(bisector, rrbnd)) != null)
{
vertices.Add(vertex);
bisector.Vertex = vertex;
bisector.YStar = vertex.Y + bottomSite.Distance(vertex);
heap.Insert(bisector);
}
}
else
{
break;
}
}
halfEdges.Clear();
var nullVerts = Edges.Where(e => e.RightVertex == null || e.LeftVertex == null).ToList();
foreach (var edge in Edges)
{
edge.ClipVertices(PlotBounds);
}
vertices.Clear();
}
private static Site RightRegion(HalfEdge he)
{
var edge = he.Edge;
return(edge == null ? null : edge.Site(LR.Other(he.LeftRight)));
}
private void Init(Edge edge, LR lr)
{
Edge = edge;
LeftRight = lr;
NextInPriorityQueue = null;
Vertex = null;
}
private int Bucket(HalfEdge halfEdge)
{
var theBucket = (int)((halfEdge.YStar - _ymin)/_deltaY*_hashSize);
if (theBucket < 0) theBucket = 0;
if (theBucket >= _hashSize) theBucket = _hashSize - 1;
return theBucket;
}
private void Initialize()
{
_count = 0;
_minBucket = 0;
_hash = new List<HalfEdge>(new HalfEdge[_hashSize]);
for (int i = 0; i < _hashSize; i++) {
_hash[i] = new HalfEdge {
NextInPriorityQueue = null
};
}
}
private void Init(Edge edge, LR lr) {
Edge = edge;
LeftRight = lr;
NextInPriorityQueue = null;
Vertex = null;
}
public void Remove(HalfEdge halfEdge)
{
halfEdge.EdgeListLeftNeighbor.EdgeListRightNeighbor = halfEdge.EdgeListRightNeighbor;
halfEdge.EdgeListRightNeighbor.EdgeListLeftNeighbor = halfEdge.EdgeListLeftNeighbor;
halfEdge.Edge = Edge.Deleted;
halfEdge.EdgeListLeftNeighbor = halfEdge.EdgeListRightNeighbor = null;
}
public void Insert(HalfEdge lb, HalfEdge newHalfEdge)
{
newHalfEdge.EdgeListLeftNeighbor = lb;
newHalfEdge.EdgeListRightNeighbor = lb.EdgeListRightNeighbor;
lb.EdgeListRightNeighbor.EdgeListLeftNeighbor = newHalfEdge;
lb.EdgeListRightNeighbor = newHalfEdge;
}