示例#1
0
文件: Voronoi.cs 项目: Slazanger/SMT
        private void FortunesAlgorithm()
        {
            Site     newSite, bottomSite, topSite, tempSite;
            Vertex   v, vertex;
            Vector2f newIntStar = Vector2f.zero;
            LR       leftRight;
            Halfedge lbnd, rbnd, llbnd, rrbnd, bisector;
            Edge     edge;

            Rectf dataBounds = sites.GetSitesBounds();

            int sqrtSitesNb            = (int)Math.Sqrt(sites.Count() + 4);
            HalfedgePriorityQueue heap = new HalfedgePriorityQueue(dataBounds.y, dataBounds.height, sqrtSitesNb);
            EdgeList        edgeList   = new EdgeList(dataBounds.x, dataBounds.width, sqrtSitesNb);
            List <Halfedge> halfEdges  = new List <Halfedge>();
            List <Vertex>   vertices   = new List <Vertex>();

            Site bottomMostSite = sites.Next();

            newSite = sites.Next();

            while (true)
            {
                if (!heap.Empty())
                {
                    newIntStar = heap.Min();
                }

                if (newSite != null &&
                    (heap.Empty() || CompareByYThenX(newSite, newIntStar) < 0))
                {
                    // New site is smallest
                    //Debug.Log("smallest: new site " + newSite);

                    // Step 8:
                    lbnd = edgeList.EdgeListLeftNeighbor(newSite.Coord); // The halfedge just to the left of newSite
                                                                         //UnityEngine.Debug.Log("lbnd: " + lbnd);
                    rbnd = lbnd.edgeListRightNeighbor;                   // The halfedge just to the right
                                                                         //UnityEngine.Debug.Log("rbnd: " + rbnd);
                    bottomSite = RightRegion(lbnd, bottomMostSite);      // This is the same as leftRegion(rbnd)
                                                                         // This Site determines the region containing the new site
                                                                         //UnityEngine.Debug.Log("new Site is in region of existing site: " + bottomSite);

                    // Step 9
                    edge = Edge.CreateBisectingEdge(bottomSite, newSite);
                    //UnityEngine.Debug.Log("new edge: " + edge);
                    edges.Add(edge);

                    bisector = Halfedge.Create(edge, LR.LEFT);
                    halfEdges.Add(bisector);
                    // Inserting two halfedges into edgelist constitutes Step 10:
                    // Insert bisector to the right of lbnd:
                    edgeList.Insert(lbnd, bisector);

                    // First half of Step 11:
                    if ((vertex = Vertex.Intersect(lbnd, bisector)) != null)
                    {
                        vertices.Add(vertex);
                        heap.Remove(lbnd);
                        lbnd.vertex = vertex;
                        lbnd.ystar  = vertex.y + newSite.Dist(vertex);
                        heap.Insert(lbnd);
                    }

                    lbnd     = bisector;
                    bisector = Halfedge.Create(edge, LR.RIGHT);
                    halfEdges.Add(bisector);
                    // Second halfedge for Step 10::
                    // Insert bisector to the right of lbnd:
                    edgeList.Insert(lbnd, bisector);

                    // Second half of Step 11:
                    if ((vertex = Vertex.Intersect(bisector, rbnd)) != null)
                    {
                        vertices.Add(vertex);
                        bisector.vertex = vertex;
                        bisector.ystar  = vertex.y + newSite.Dist(vertex);
                        heap.Insert(bisector);
                    }

                    newSite = sites.Next();
                }
                else if (!heap.Empty())
                {
                    // Intersection is smallest
                    lbnd       = heap.ExtractMin();
                    llbnd      = lbnd.edgeListLeftNeighbor;
                    rbnd       = lbnd.edgeListRightNeighbor;
                    rrbnd      = rbnd.edgeListRightNeighbor;
                    bottomSite = LeftRegion(lbnd, bottomMostSite);
                    topSite    = RightRegion(rbnd, bottomMostSite);
                    // These three sites define a Delaunay triangle
                    // (not actually using these for anything...)
                    // triangles.Add(new Triangle(bottomSite, topSite, RightRegion(lbnd, bottomMostSite)));

                    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);
                    leftRight = LR.LEFT;
                    if (bottomSite.y > topSite.y)
                    {
                        tempSite   = bottomSite;
                        bottomSite = topSite;
                        topSite    = tempSite;
                        leftRight  = LR.RIGHT;
                    }
                    edge = Edge.CreateBisectingEdge(bottomSite, topSite);
                    edges.Add(edge);
                    bisector = Halfedge.Create(edge, leftRight);
                    halfEdges.Add(bisector);
                    edgeList.Insert(llbnd, bisector);
                    edge.SetVertex(LR.Other(leftRight), v);
                    if ((vertex = Vertex.Intersect(llbnd, bisector)) != null)
                    {
                        vertices.Add(vertex);
                        heap.Remove(llbnd);
                        llbnd.vertex = vertex;
                        llbnd.ystar  = vertex.y + bottomSite.Dist(vertex);
                        heap.Insert(llbnd);
                    }
                    if ((vertex = Vertex.Intersect(bisector, rrbnd)) != null)
                    {
                        vertices.Add(vertex);
                        bisector.vertex = vertex;
                        bisector.ystar  = vertex.y + bottomSite.Dist(vertex);
                        heap.Insert(bisector);
                    }
                }
                else
                {
                    break;
                }
            }

            // Heap should be empty now
            heap.Dispose();
            edgeList.Dispose();

            foreach (Halfedge halfedge in halfEdges)
            {
                halfedge.ReallyDispose();
            }
            halfEdges.Clear();

            // we need the vertices to clip the edges
            foreach (Edge e in edges)
            {
                e.ClipVertices(plotBounds);
            }
            // But we don't actually ever use them again!
            foreach (Vertex ve in vertices)
            {
                ve.Dispose();
            }
            vertices.Clear();
        }