87 lines
2.3 KiB
C#
87 lines
2.3 KiB
C#
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using UnityEngine;
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using System.Collections;
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using System.Collections.Generic;
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namespace TGS.Geom {
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class SweepEventSet {
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public List<SweepEvent>eventSet;
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public SweepEventSet () {
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eventSet = new List<SweepEvent> (1000);
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}
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public void Remove (SweepEvent key) {
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int keyIndex = eventSet.IndexOf (key);
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if (keyIndex == -1)
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return;
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eventSet.RemoveAt (keyIndex);
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}
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public int Insert (SweepEvent item) {
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int count = eventSet.Count;
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if (count == 0) {
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eventSet.Add (item);
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return 0;
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}
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eventSet.Add (null); // Expand the Vector by one.
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int i = count - 1;
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while (i >= 0 && SegmentCompare(item, eventSet[i])) {
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eventSet [i + 1] = eventSet [i];
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i--;
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}
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eventSet [i + 1] = item;
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return i + 1;
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}
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double signedArea (Point p0, Point p1, Point p2) {
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return (p0.x - p2.x) * (p1.y - p2.y) - (p1.x - p2.x) * (p0.y - p2.y);
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}
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private bool SegmentCompare (SweepEvent e1, SweepEvent e2) {
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if (e1.Equals(e2))
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return false;
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if (signedArea (e1.p, e1.otherSE.p, e2.p) != 0 || signedArea (e1.p, e1.otherSE.p, e2.otherSE.p) != 0) {
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// Segments are not collinear
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// If they share their left endpoint use the right endpoint to sort
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if (Point.EqualsBoth(e1.p, e2.p))
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return e1.isBelow (e2.otherSE.p);
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if (CompareSweepEvent (e1, e2))
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return e2.isAbove (e1.p);
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return e1.isBelow (e2.p);
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}
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if (Point.EqualsBoth(e1.p, e2.p)) // Segments colinear
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return false;
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return CompareSweepEvent (e1, e2);
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}
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// Should only be called by segmentCompare
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private bool CompareSweepEvent (SweepEvent e1, SweepEvent e2) {
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if (e1.p.x > e2.p.x) // Different x coordinate
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return true;
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if (e2.p.x > e1.p.x) // Different x coordinate
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return false;
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if (e1.p != e2.p) // Different points, but same x coordinate. The event with lower y coordinate is processed first
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return e1.p.y > e2.p.y;
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if (e1.isLeft != e2.isLeft) // Same point, but one is a left endpoint and the other a right endpoint. The right endpoint is processed first
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return e1.isLeft;
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// Same point, both events are left endpoints or both are right endpoints. The event associate to the bottom segment is processed first
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return e1.isAbove (e2.otherSE.p);
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}
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}
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}
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