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https://git.do.srb2.org/STJr/UltimateZoneBuilder.git
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183 lines
4.7 KiB
C#
Executable file
183 lines
4.7 KiB
C#
Executable file
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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.Generic;
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using System.Drawing;
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#endregion
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namespace CodeImp.DoomBuilder.Geometry
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{
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[Serializable]
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public sealed class EarClipPolygon : LinkedList<EarClipVertex>
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{
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#region ================== Variables
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// Tree variables
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private List<EarClipPolygon> children;
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private bool inner;
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#endregion
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#region ================== Properties
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public List<EarClipPolygon> Children { get { return children; } }
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public bool Inner { get { return inner; } set { inner = value; } }
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#endregion
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#region ================== Constructors
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// Constructor
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internal EarClipPolygon()
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{
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// Initialize
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children = new List<EarClipPolygon>();
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}
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// Constructor
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internal EarClipPolygon(EarClipPolygon p, EarClipVertex add) : base(p)
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{
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// Initialize
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base.AddLast(add);
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children = new List<EarClipPolygon>();
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}
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#endregion
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#region ================== Methods
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// This merges a polygon into this one
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public void Add(EarClipPolygon p)
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{
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// Initialize
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foreach(EarClipVertex v in p) base.AddLast(v);
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}
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// This calculates the area
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public double CalculateArea()
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{
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double area = 0;
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LinkedListNode<EarClipVertex> v = First;
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do
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{
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EarClipVertex v1 = v.Value;
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EarClipVertex v2 = (v.Next != null) ? v.Next.Value : First.Value;
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area += (v2.Position.x + v1.Position.x) * (v2.Position.y - v1.Position.y);
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v = v.Next;
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}
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while (v != null);
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return Math.Abs(area * 0.5f);
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}
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// This creates a bounding box from the outer polygon
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public RectangleF CreateBBox()
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{
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double left = float.MaxValue;
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double right = float.MinValue;
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double top = float.MaxValue;
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double bottom = float.MinValue;
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foreach(EarClipVertex v in this)
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{
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if(v.Position.x < left) left = v.Position.x;
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if(v.Position.x > right) right = v.Position.x;
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if(v.Position.y < top) top = v.Position.y;
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if(v.Position.y > bottom) bottom = v.Position.y;
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}
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return new RectangleF((float)left, (float)top, (float)(right - left), (float)(bottom - top));
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}
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// Point inside the polygon?
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// See: http://paulbourke.net/geometry/polygonmesh/index.html#insidepoly
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public bool Intersect(Vector2D p)
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{
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Vector2D v1 = base.Last.Value.Position;
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LinkedListNode<EarClipVertex> n = base.First;
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uint c = 0;
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Vector2D v2;
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// Go for all vertices
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while(n != null)
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{
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// Get next vertex
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v2 = n.Value.Position;
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// Check for intersection
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if(v1.y != v2.y //mxd. If line is not horizontal...
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&& p.y > (v1.y < v2.y ? v1.y : v2.y) //mxd. ...And test point y intersects with the line y bounds...
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&& p.y <= (v1.y > v2.y ? v1.y : v2.y) //mxd
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&& (p.x < (v1.x < v2.x ? v1.x : v2.x) || (p.x <= (v1.x > v2.x ? v1.x : v2.x) //mxd. ...And test point x is to the left of the line, or is inside line x bounds and intersects it
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&& (v1.x == v2.x || p.x <= ((p.y - v1.y) * (v2.x - v1.x) / (v2.y - v1.y) + v1.x)))))
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c++; //mxd. ...Count the line as crossed
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// Move to next
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v1 = v2;
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n = n.Next;
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}
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// Inside this polygon when we crossed odd number of polygon lines
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if(c % 2 != 0)
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{
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// Check if not inside the children
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foreach(EarClipPolygon child in children)
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{
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// Inside this child? Then it is not inside this polygon.
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if(child.Intersect(p)) return false;
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}
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// Inside polygon!
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return true;
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}
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// Not inside the polygon
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return false;
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}
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// This inserts a polygon if it is a child of this one
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public bool InsertChild(EarClipPolygon p)
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{
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// Polygon must have at least 1 vertex
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if(p.Count == 0) return false;
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// Check if it can be inserted at a lower level
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foreach(EarClipPolygon child in children)
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{
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if(child.InsertChild(p)) return true;
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}
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// Check if it can be inserted here
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if(this.Intersect(p.First.Value.Position))
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{
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// Make the polygon the inverse of this one
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p.Inner = !inner;
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children.Add(p);
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return true;
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}
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// Can't insert it as a child
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return false;
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}
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#endregion
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}
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}
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