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https://git.do.srb2.org/STJr/UltimateZoneBuilder.git
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706 lines
22 KiB
C#
706 lines
22 KiB
C#
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#region ================== Copyright (c) 2007 Pascal vd Heiden
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/*
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* Copyright (c) 2007 Pascal vd Heiden, www.codeimp.com
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* This program is released under GNU General Public License
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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*/
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#endregion
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#region ================== Namespaces
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using System;
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using System.Collections;
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using System.Collections.Generic;
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using System.Globalization;
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using System.Text;
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using CodeImp.DoomBuilder.Geometry;
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using CodeImp.DoomBuilder.Rendering;
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using SlimDX.Direct3D9;
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using System.Drawing;
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using CodeImp.DoomBuilder.Map;
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using System.Collections.ObjectModel;
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#endregion
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namespace CodeImp.DoomBuilder.Geometry
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{
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/// <summary>
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/// Responsible for creating sector polygons.
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/// Performs triangulation of sectors by using ear clipping.
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/// </summary>
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public sealed class Triangulation
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{
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#region ================== Delegates
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// For debugging purpose only!
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// These are not called in a release build
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public delegate void ShowLine(Vector2D v1, Vector2D v2, PixelColor c);
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public delegate void ShowPolygon(EarClipPolygon p, PixelColor c);
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public delegate void ShowPoint(Vector2D v, int c);
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public delegate void ShowEarClip(EarClipVertex[] found, LinkedList<EarClipVertex> remaining);
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// For debugging purpose only!
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// These are not called in a release build
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public ShowLine OnShowLine;
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public ShowPolygon OnShowPolygon;
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public ShowPoint OnShowPoint;
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public ShowEarClip OnShowEarClip;
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#endregion
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#region ================== Constants
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#endregion
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#region ================== Variables
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// Number of vertices per island
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private ReadOnlyCollection<int> islandvertices;
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// Vertices that result from the triangulation, 3 per triangle.
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private ReadOnlyCollection<Vector2D> vertices;
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// These sidedefs match with the vertices. If a vertex is not the start
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// along a sidedef, this list contains a null entry for that vertex.
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private ReadOnlyCollection<Sidedef> sidedefs;
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#endregion
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#region ================== Properties
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public ReadOnlyCollection<int> IslandVertices { get { return islandvertices; } }
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public ReadOnlyCollection<Vector2D> Vertices { get { return vertices; } }
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public ReadOnlyCollection<Sidedef> Sidedefs { get { return sidedefs; } }
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#endregion
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#region ================== Constructor / Disposer
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// I don't like using constructors that do more than simple initialization work
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public static Triangulation Create(Sector sector)
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{
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return new Triangulation(sector);
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}
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// Constructor
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private Triangulation(Sector s)
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{
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// Initialize
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List<EarClipPolygon> polys;
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List<int> islandslist = new List<int>();
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List<Vector2D> verticeslist = new List<Vector2D>();
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List<Sidedef> sidedefslist = new List<Sidedef>();
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// We have no destructor
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GC.SuppressFinalize(this);
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/*
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* This process is divided into several steps:
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*
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* 1) Tracing the sector lines to find clockwise outer polygons
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* and counter-clockwise inner polygons. These are arranged in a
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* polygon tree for the next step.
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*
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* 2) Cutting the inner polygons to make a flat list of only
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* outer polygons.
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*
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* 3) Ear-clipping the polygons to create triangles.
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*
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*/
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// TRACING
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polys = DoTrace(s);
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// CUTTING
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DoCutting(polys);
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// EAR-CLIPPING
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foreach(EarClipPolygon p in polys)
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islandslist.Add(DoEarClip(p, verticeslist, sidedefslist));
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// Make arrays
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islandvertices = Array.AsReadOnly<int>(islandslist.ToArray());
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vertices = Array.AsReadOnly<Vector2D>(verticeslist.ToArray());
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sidedefs = Array.AsReadOnly<Sidedef>(sidedefslist.ToArray());
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}
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#endregion
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#region ================== Tracing
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// This traces sector lines to create a polygon tree
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private List<EarClipPolygon> DoTrace(Sector s)
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{
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Dictionary<Sidedef, bool> todosides = new Dictionary<Sidedef, bool>(s.Sidedefs.Count);
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Dictionary<Vertex, Vertex> ignores = new Dictionary<Vertex,Vertex>();
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List<EarClipPolygon> root = new List<EarClipPolygon>();
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SidedefsTracePath path;
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EarClipPolygon newpoly;
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Vertex start;
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// Fill the dictionary
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// The bool value is used to indicate lines which has been visited in the trace
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foreach(Sidedef sd in s.Sidedefs) todosides.Add(sd, false);
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// First remove all sides that refer to the same sector on both sides of the line
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RemoveDoubleSidedefReferences(todosides, s.Sidedefs);
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// Continue until all sidedefs have been processed
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while(todosides.Count > 0)
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{
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// Reset all visited indicators
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foreach(Sidedef sd in s.Sidedefs) if(todosides.ContainsKey(sd)) todosides[sd] = false;
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// Find the right-most vertex to start a trace with.
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// This guarantees that we start out with an outer polygon and we just
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// have to check if it is inside a previously found polygon.
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start = FindRightMostVertex(todosides, ignores);
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// No more possible start vertex found?
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// Then leave with what we have up till now.
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if(start == null) break;
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// Trace to find a polygon
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path = DoTracePath(new SidedefsTracePath(), start, null, s, todosides);
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// If tracing is not possible (sector not closed?)
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// then add the start to the ignore list and try again later
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if(path == null)
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{
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// Ignore vertex as start
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ignores.Add(start, start);
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}
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else
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{
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// Remove the sides found in the path
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foreach(Sidedef sd in path) todosides.Remove(sd);
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// Create the polygon
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newpoly = path.MakePolygon();
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#if DEBUG
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if(OnShowPolygon != null) OnShowPolygon(newpoly, General.Colors.Selection);
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#endif
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// Determine where this polygon goes in our tree
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foreach(EarClipPolygon p in root)
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{
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// Insert if it belongs as a child
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if(p.InsertChild(newpoly))
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{
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// Done
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newpoly = null;
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break;
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}
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}
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// Still not inserted in our tree?
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if(newpoly != null)
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{
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// Then add it at root level as outer polygon
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newpoly.Inner = false;
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root.Add(newpoly);
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}
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}
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}
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// Return result
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return root;
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}
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// This recursively traces a path
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// Returns the resulting TracePath when the search is complete
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// or returns null when no path found.
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private SidedefsTracePath DoTracePath(SidedefsTracePath history, Vertex fromhere, Vertex findme, Sector sector, Dictionary<Sidedef, bool> sides)
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{
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SidedefsTracePath nextpath;
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SidedefsTracePath result;
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Vertex nextvertex;
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List<Sidedef> allsides;
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SidedefAngleSorter sorter;
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// Found the vertex we are tracing to?
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if(fromhere == findme) return history;
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// On the first run, findme is null (otherwise the trace would end
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// immeditely when it starts) so set findme here on the first run.
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if(findme == null) findme = fromhere;
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// Make a list of sides referring to the same sector
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allsides = new List<Sidedef>(fromhere.Linedefs.Count * 2);
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foreach(Linedef l in fromhere.Linedefs)
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{
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// Should we go along the front or back side?
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// This is very important for clockwise polygon orientation!
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if(l.Start == fromhere)
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{
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// Front side of line connected to sector?
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if((l.Front != null) && (l.Front.Sector == sector))
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{
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// Visit here when not visited yet
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if(sides.ContainsKey(l.Front) && !sides[l.Front]) allsides.Add(l.Front);
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}
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}
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else
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{
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// Back side of line connected to sector?
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if((l.Back != null) && (l.Back.Sector == sector))
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{
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// Visit here when not visited yet
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if(sides.ContainsKey(l.Back) && !sides[l.Back]) allsides.Add(l.Back);
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}
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}
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}
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// Previous line available?
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if(history.Count > 0)
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{
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// This is done to ensure the tracing works along vertices that are shared by
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// more than 2 lines/sides of the same sector. We must continue tracing along
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// the first next smallest delta angle! This sorts the smallest delta angle to
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// the top of the list.
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sorter = new SidedefAngleSorter(history[history.Count - 1], fromhere);
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allsides.Sort(sorter);
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}
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// Go for all lines connected to this vertex
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foreach(Sidedef s in allsides)
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{
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// Mark sidedef as visited and move to next vertex
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sides[s] = true;
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nextpath = new SidedefsTracePath(history, s);
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if(s.Line.Start == fromhere) nextvertex = s.Line.End; else nextvertex = s.Line.Start;
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// TEST
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#if DEBUG
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if(s.IsFront)
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{
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if(OnShowLine != null) OnShowLine(s.Line.Start.Position, s.Line.End.Position, PixelColor.FromColor(Color.Chartreuse));
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}
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else
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{
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if(OnShowLine != null) OnShowLine(s.Line.Start.Position, s.Line.End.Position, PixelColor.FromColor(Color.DeepSkyBlue));
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}
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#endif
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result = DoTracePath(nextpath, nextvertex, findme, sector, sides);
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if(result != null) return result;
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}
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// Nothing found
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return null;
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}
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// This removes all sidedefs which has a sidedefs on the other side
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// of the same line that refers to the same sector. These are removed
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// because they are useless and make the triangulation inefficient.
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private static void RemoveDoubleSidedefReferences(Dictionary<Sidedef, bool> todosides, ICollection<Sidedef> sides)
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{
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// Go for all sides
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foreach(Sidedef sd in sides)
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{
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// Double sided?
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if(sd.Other != null)
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{
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// Referring to the same sector on both sides?
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if(sd.Sector == sd.Other.Sector)
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{
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// Remove this one
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todosides.Remove(sd);
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}
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}
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}
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}
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// This finds the right-most vertex to start tracing with
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private static Vertex FindRightMostVertex(Dictionary<Sidedef, bool> sides, Dictionary<Vertex, Vertex> ignores)
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{
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Vertex found = null;
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// Go for all sides to find the right-most side
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foreach(KeyValuePair<Sidedef, bool> sd in sides)
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{
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// First found?
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if((found == null) && !ignores.ContainsKey(sd.Key.Line.Start)) found = sd.Key.Line.Start;
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if((found == null) && !ignores.ContainsKey(sd.Key.Line.End)) found = sd.Key.Line.End;
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// Compare?
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if(found != null)
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{
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// Check if more to the right than the previous found
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if((sd.Key.Line.Start.Position.x > found.Position.x) && !ignores.ContainsKey(sd.Key.Line.Start)) found = sd.Key.Line.Start;
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if((sd.Key.Line.End.Position.x > found.Position.x) && !ignores.ContainsKey(sd.Key.Line.End)) found = sd.Key.Line.End;
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}
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}
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// Return result
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return found;
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}
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#endregion
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#region ================== Cutting
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// This cuts into outer polygons to solve inner polygons and make the polygon tree flat
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private void DoCutting(List<EarClipPolygon> polys)
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{
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Queue<EarClipPolygon> todo = new Queue<EarClipPolygon>(polys);
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// Begin processing outer polygons
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while(todo.Count > 0)
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{
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// Get outer polygon to process
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EarClipPolygon p = todo.Dequeue();
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// Any inner polygons to work with?
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if(p.Children.Count > 0)
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{
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// Go for all the children
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foreach(EarClipPolygon c in p.Children)
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{
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// The children of the children are outer polygons again,
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// so move them to the root and add for processing
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polys.AddRange(c.Children);
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foreach(EarClipPolygon sc in c.Children) todo.Enqueue(sc);
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// Remove from inner polygon
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c.Children.Clear();
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}
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// Now do some cutting on this polygon to merge the inner polygons
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MergeInnerPolys(p);
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}
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}
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}
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// This takes an outer polygon and a set of inner polygons to start cutting on
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private void MergeInnerPolys(EarClipPolygon p)
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{
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LinkedList<EarClipPolygon> todo = new LinkedList<EarClipPolygon>(p.Children);
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LinkedListNode<EarClipVertex> start;
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LinkedListNode<EarClipPolygon> ip;
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LinkedListNode<EarClipPolygon> found;
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LinkedListNode<EarClipVertex> foundstart;
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// Continue until no more inner polygons to process
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while(todo.Count > 0)
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{
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// Find the inner polygon with the highest x vertex
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found = null;
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foundstart = null;
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ip = todo.First;
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while(ip != null)
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{
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start = FindRightMostVertex(ip.Value);
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if((foundstart == null) || (start.Value.Position.x > foundstart.Value.Position.x))
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{
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// Found a better start
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found = ip;
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foundstart = start;
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}
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// Next!
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ip = ip.Next;
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}
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// Remove from todo list
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todo.Remove(found);
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// Get cut start and end
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SplitOuterWithInner(foundstart, p, found.Value);
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}
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// Remove the children, they should be merged in the polygon by now
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p.Children.Clear();
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}
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// This finds the right-most vertex in an inner polygon to use for cut startpoint.
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private static LinkedListNode<EarClipVertex> FindRightMostVertex(EarClipPolygon p)
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{
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LinkedListNode<EarClipVertex> found = p.First;
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LinkedListNode<EarClipVertex> v = found.Next;
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// Go for all vertices to find the on with the biggest x value
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while(v != null)
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{
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if(v.Value.Position.x > found.Value.Position.x) found = v;
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v = v.Next;
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}
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// Return result
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return found;
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}
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// This finds the cut coordinates and splits the other poly with inner vertices
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private static void SplitOuterWithInner(LinkedListNode<EarClipVertex> start, EarClipPolygon p, EarClipPolygon inner)
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{
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Line2D starttoright = new Line2D(start.Value.Position, start.Value.Position + new Vector2D(1000.0f, 0.0f));
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LinkedListNode<EarClipVertex> v1, v2;
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LinkedListNode<EarClipVertex> insertbefore = null;
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float u, ul, foundu = float.MaxValue;
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EarClipVertex split;
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// Go for all lines in the outer polygon
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v1 = p.Last;
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v2 = p.First;
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while(v2 != null)
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{
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// Check if the line is to the right of start
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if((v1.Value.Position.x > start.Value.Position.x) ||
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(v2.Value.Position.x > start.Value.Position.x))
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{
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// Find intersection
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Line2D pl = new Line2D(v1.Value.Position, v2.Value.Position);
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pl.GetIntersection(starttoright, out u, out ul);
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if(float.IsNaN(u))
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{
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// We have found a line that is perfectly horizontal
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// (parallel to the cut scan line) Check if the line
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// is overlapping the cut scan line.
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if(v1.Value.Position.y == start.Value.Position.y)
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{
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// Calculate distance of each vertex in units
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u = starttoright.GetNearestOnLine(v1.Value.Position);
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ul = starttoright.GetNearestOnLine(v2.Value.Position);
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// Rule out vertices before the scan line
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if(u < 0) u = float.MaxValue;
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if(ul < 0) ul = float.MaxValue;
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// Choose closest of both vertices
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if((u < ul) && (u < foundu))
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{
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insertbefore = v2;
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foundu = u;
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}
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else if((u > ul) && (ul < foundu))
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{
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insertbefore = v2;
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foundu = ul;
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}
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}
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}
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// Found a closer match?
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else if((ul >= 0) && (ul <= 1) && (u > 0) && (u < foundu))
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{
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// Found a closer intersection
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insertbefore = v2;
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foundu = u;
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}
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}
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// Next
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v1 = v2;
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v2 = v2.Next;
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}
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// Found anything?
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if(insertbefore != null)
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{
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Sidedef sd = (insertbefore.Previous == null) ? insertbefore.List.Last.Value.Sidedef : insertbefore.Previous.Value.Sidedef;
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// Find the position where we have to split the outer polygon
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split = new EarClipVertex(starttoright.GetCoordinatesAt(foundu), null);
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// Insert manual split vertices
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p.AddBefore(insertbefore, new EarClipVertex(split, sd));
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// Start inserting from the start (do I make sense this time?)
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v1 = start;
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do
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{
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// Insert inner polygon vertex
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p.AddBefore(insertbefore, new EarClipVertex(v1.Value));
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if(v1.Next != null) v1 = v1.Next; else v1 = v1.List.First;
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}
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while(v1 != start);
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// Insert manual split vertices
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p.AddBefore(insertbefore, new EarClipVertex(start.Value, sd));
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p.AddBefore(insertbefore, new EarClipVertex(split, sd));
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}
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}
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#endregion
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#region ================== Ear Clipping
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// This clips a polygon and returns the triangles
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// The polygon may not have any holes or islands
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/// See: http://www.geometrictools.com/Documentation/TriangulationByEarClipping.pdf
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private int DoEarClip(EarClipPolygon poly, List<Vector2D> verticeslist, List<Sidedef> sidedefslist)
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{
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LinkedList<EarClipVertex> verts = new LinkedList<EarClipVertex>();
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List<EarClipVertex> convexes = new List<EarClipVertex>(poly.Count);
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LinkedList<EarClipVertex> reflexes = new LinkedList<EarClipVertex>();
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LinkedList<EarClipVertex> eartips = new LinkedList<EarClipVertex>();
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EarClipVertex v, v1, v2;
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EarClipVertex[] t, t1, t2;
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int countvertices = 0;
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// Go for all vertices to fill list
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foreach(EarClipVertex vec in poly)
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vec.SetVertsLink(verts.AddLast(vec));
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// Optimization: Vertices which have lines with the
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// same angle are useless. Remove them!
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v = verts.First.Value;
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while(v != null)
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{
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// Get the next vertex
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if(v.MainListNode.Next != null) v1 = v.MainListNode.Next.Value; else v1 = null;
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// Get triangle for v
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t = GetTriangle(v);
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// Check if both lines have the same angle
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Line2D a = new Line2D(t[0].Position, t[1].Position);
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Line2D b = new Line2D(t[1].Position, t[2].Position);
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if(Math.Abs(Angle2D.Difference(a.GetAngle(), b.GetAngle())) < 0.00001f)
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{
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// Same angles, remove vertex
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v.Remove();
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}
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// Next!
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v = v1;
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}
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// Go for all vertices to determine reflex or convex
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foreach(EarClipVertex vv in verts)
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{
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// Add to reflex or convex list
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if(IsReflex(GetTriangle(vv))) vv.AddReflex(reflexes); else convexes.Add(vv);
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}
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// Go for all convex vertices to see if they are ear tips
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foreach(EarClipVertex cv in convexes)
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{
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// Add when this is a valid ear
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t = GetTriangle(cv);
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if(CheckValidEar(t, reflexes)) cv.AddEarTip(eartips);
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}
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// Process ears until done
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while((eartips.Count > 0) && (verts.Count > 2))
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{
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// Get next ear
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v = eartips.First.Value;
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t = GetTriangle(v);
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// Add ear as triangle
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AddTriangleToList(t, verticeslist, sidedefslist, (verts.Count == 3));
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countvertices += 3;
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// Remove this ear from all lists
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v.Remove();
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v1 = t[0];
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v2 = t[2];
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// Test first neighbour
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t1 = GetTriangle(v1);
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if(IsReflex(t1))
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{
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// List as reflex if not listed yet
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if(!v1.IsReflex) v1.AddReflex(reflexes);
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v1.RemoveEarTip();
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}
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else
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{
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// Remove from reflexes
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v1.RemoveReflex();
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}
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// Test second neighbour
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t2 = GetTriangle(v2);
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if(IsReflex(t2))
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{
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// List as reflex if not listed yet
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if(!v2.IsReflex) v2.AddReflex(reflexes);
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v2.RemoveEarTip();
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}
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else
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{
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// Remove from reflexes
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v2.RemoveReflex();
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}
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// Check if any neightbour have become a valid or invalid ear
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if(!v1.IsReflex && CheckValidEar(t1, reflexes)) v1.AddEarTip(eartips); else v1.RemoveEarTip();
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if(!v2.IsReflex && CheckValidEar(t2, reflexes)) v2.AddEarTip(eartips); else v2.RemoveEarTip();
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}
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// Dispose remaining vertices
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foreach(EarClipVertex ecv in verts) ecv.Dispose();
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// Return the number of vertices in the result
|
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return countvertices;
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}
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// This checks if a given ear is a valid (no intersections from reflex vertices)
|
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private bool CheckValidEar(EarClipVertex[] t, LinkedList<EarClipVertex> reflexes)
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{
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// Go for all reflex vertices
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foreach(EarClipVertex rv in reflexes)
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{
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// Return false on intersection
|
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if(PointInsideTriangle(t, rv.Position) &&
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(rv != t[0]) && (rv != t[1]) && (rv != t[2])) return false;
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}
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// Valid ear!
|
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return true;
|
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}
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|
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// This returns the 3-vertex array triangle for an ear
|
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private static EarClipVertex[] GetTriangle(EarClipVertex v)
|
|
{
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EarClipVertex[] t = new EarClipVertex[3];
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if(v.MainListNode.Previous == null) t[0] = v.MainListNode.List.Last.Value; else t[0] = v.MainListNode.Previous.Value;
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t[1] = v;
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if(v.MainListNode.Next == null) t[2] = v.MainListNode.List.First.Value; else t[2] = v.MainListNode.Next.Value;
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return t;
|
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}
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|
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// This checks if a vertex is reflex (corner > 180 deg) or convex (corner < 180 deg)
|
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private static bool IsReflex(EarClipVertex[] t)
|
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{
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// Return true when corner is > 180 deg
|
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//return (Line2D.GetSideOfLine(t[0].Position, t[2].Position, t[1].Position) < 0.00001f);
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return (Line2D.GetSideOfLine(t[0].Position, t[2].Position, t[1].Position) < 0);
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}
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|
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// This checks if a point is inside a triangle
|
|
// NOTE: vertices in t must be in clockwise order!
|
|
private static bool PointInsideTriangle(EarClipVertex[] t, Vector2D p)
|
|
{
|
|
return (Line2D.GetSideOfLine(t[0].Position, t[1].Position, p) < 0.00001f) &&
|
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(Line2D.GetSideOfLine(t[1].Position, t[2].Position, p) < 0.00001f) &&
|
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(Line2D.GetSideOfLine(t[2].Position, t[0].Position, p) < 0.00001f);
|
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}
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|
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// This adds an array of vertices
|
|
private void AddTriangleToList(EarClipVertex[] triangle, List<Vector2D> verticeslist, List<Sidedef> sidedefslist, bool last)
|
|
{
|
|
// Create triangle
|
|
verticeslist.Add(triangle[0].Position);
|
|
sidedefslist.Add(triangle[0].Sidedef);
|
|
verticeslist.Add(triangle[1].Position);
|
|
sidedefslist.Add(triangle[1].Sidedef);
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|
verticeslist.Add(triangle[2].Position);
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|
if(!last) sidedefslist.Add(null); else sidedefslist.Add(triangle[2].Sidedef);
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|
|
// Modify the first earclipvertex of this triangle, it no longer lies along a sidedef
|
|
triangle[0].Sidedef = null;
|
|
}
|
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#endregion
|
|
}
|
|
}
|