/* Poly2Tri * Copyright (c) 2009-2010, Poly2Tri Contributors * http://code.google.com/p/poly2tri/ * * All rights reserved. * * Redistribution and use in source and binary forms, with or without modification, * are permitted provided that the following conditions are met: * * * Redistributions of source code must retain the above copyright notice, * this list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * * Neither the name of Poly2Tri nor the names of its contributors may be * used to endorse or promote products derived from this software without specific * prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ /// Changes from the Java version /// Removed BST code, but not all artifacts of it /// Future possibilities /// Eliminate Add/RemoveNode ? /// Comments comments and more comments! using System.Text; using System; namespace UnityEngine.ProBuilder.Poly2Tri { /** * @author Thomas Åhlen (thahlen@gmail.com) */ class AdvancingFront { public AdvancingFrontNode Head; public AdvancingFrontNode Tail; protected AdvancingFrontNode Search; public AdvancingFront( AdvancingFrontNode head, AdvancingFrontNode tail ) { this.Head = head; this.Tail = tail; this.Search = head; AddNode(head); AddNode(tail); } public void AddNode( AdvancingFrontNode node ) { } public void RemoveNode( AdvancingFrontNode node ) { } public override string ToString() { StringBuilder sb = new StringBuilder(); AdvancingFrontNode node = Head; while (node != Tail) { sb.Append(node.Point.X).Append("->"); node = node.Next; } sb.Append(Tail.Point.X); return sb.ToString(); } /// /// MM: This seems to be used by LocateNode to guess a position in the implicit linked list of AdvancingFrontNodes near x /// Removed an overload that depended on this being exact /// private AdvancingFrontNode FindSearchNode( double x ) { return Search; } /// /// We use a balancing tree to locate a node smaller or equal to given key value (in theory) /// public AdvancingFrontNode LocateNode( TriangulationPoint point ) { return LocateNode(point.X); } private AdvancingFrontNode LocateNode( double x ) { AdvancingFrontNode node = FindSearchNode(x); if (x < node.Value) { while ((node = node.Prev) != null) if (x >= node.Value) { Search = node; return node; } } else { while ((node = node.Next) != null) if (x < node.Value) { Search = node.Prev; return node.Prev; } } return null; } /// /// This implementation will use simple node traversal algorithm to find a point on the front /// public AdvancingFrontNode LocatePoint( TriangulationPoint point ) { double px = point.X; AdvancingFrontNode node = FindSearchNode(px); double nx = node.Point.X; if (px == nx) { if (point != node.Point) { // We might have two nodes with same x value for a short time if (point == node.Prev.Point) { node = node.Prev; } else if (point == node.Next.Point) { node = node.Next; } else { throw new Exception("Failed to find Node for given afront point"); } } } else if (px < nx) { while ((node = node.Prev) != null) if (point == node.Point) break; } else { while ((node = node.Next) != null) if (point == node.Point) break; } Search = node; return node; } } }