NLDClient-yudde/ProjectNLD/Assets/ThirdParty/TerrainGridSystem/Scripts/Geom/PolygonClipping/PointChain.cs

using UnityEngine;
using System.Collections;
using System.Collections.Generic;

namespace TGS.Geom {
	class PointChain {
		public bool closed;
		public List<Point> pointList;

		public void Init(Segment s) {
			Clear();
			pointList.Add (s.start);
			pointList.Add (s.end);
		}

		public void Clear() {
			closed = false;
            if (pointList == null) {
                pointList = new List<Point>(12);
            } else {
                pointList.Clear();
            }
        }

        // Links a segment to the pointChain
        public bool LinkSegment (Segment s) {
			Point front = pointList [0];
			Point back = pointList [pointList.Count - 1];
			
			if (Point.EqualsBoth (s.start, front)) {
				if (Point.EqualsBoth (s.end, back)) {
					closed = true;
				} else {
					pointList.Insert (0, s.end);
				}
				return true;
			} else if (Point.EqualsBoth (s.end, back)) {
				if (Point.EqualsBoth (s.start, front)) {
					closed = true;
				} else {
					pointList.Add (s.start);
				}
				return true;
			} else if (Point.EqualsBoth (s.end, front)) {
				if (Point.EqualsBoth (s.start, back)) {
					closed = true;
				} else {
					pointList.Insert (0, s.start);
				}
				return true;
			} else if (Point.EqualsBoth (s.start, back)) {
				if (Point.EqualsBoth (s.end, front)) {
					closed = true;
				} else {
					pointList.Add (s.end);
				}

				return true;
			}
			
			return false;
		}
		
		// Links another pointChain onto this point chain.
		static List<Point> temp = new List<Point>(100);
		public bool LinkPointChain (PointChain chain) {
			Point firstPoint = pointList [0];
			Point lastPoint = pointList [pointList.Count - 1];
			
			Point chainFront = chain.pointList [0];
			Point chainBack = chain.pointList [chain.pointList.Count - 1];
			
			if (Point.EqualsBoth (chainFront, lastPoint)) {
				temp.Clear ();
				int chainPointListCount = chain.pointList.Count;
				for (int k = 1; k < chainPointListCount; k++) {
					temp.Add (chain.pointList [k]);
				}
				pointList.AddRange (temp);
				return true;
			}
			
			if (Point.EqualsBoth (chainBack, firstPoint)) {
				temp.Clear();
				temp.AddRange (chain.pointList);
				int pointListCount = pointList.Count;
				for (int k = 1; k < pointListCount; k++) {
					temp.Add (pointList [k]);
				}
				pointList.Clear ();
				pointList.AddRange (temp);
				return true;
			}
			
			if (Point.EqualsBoth (chainFront, firstPoint)) {
//				List<Point> temp = new List<Point> (chain.pointList);
				temp.Clear();
				temp.AddRange (chain.pointList);
				temp.Reverse ();
				int pointListCount = pointList.Count;
//				temp.Capacity += pointListCount;
				for (int k = 1; k < pointListCount; k++) {
					temp.Add (pointList [k]);
				}
				pointList.Clear ();
				pointList.AddRange (temp);
//				pointList = temp;
				return true;
			}
			
			if (Point.EqualsBoth (chainBack, lastPoint)) {
				pointList.RemoveAt (pointList.Count - 1);
				temp.Clear ();
				temp.AddRange (chain.pointList);
//				List<Point> temp = new List<Point> (chain.pointList);
				temp.Reverse ();
				pointList.AddRange (temp);
				return true;
			}
			return false;
		}
		
	}

}