Half Edge magic

main/CompGeo.pde

@@ -1,19 +1,21 @@
 public static class CompGeo {
 
-  public int CCW(Point a, Point b, Point c) {
+  public static int CCW(Point a, Point b, Point c) {
      // Return 1 if turn abc is ccw -1 if turn abc is cw 0 if no turn
      float f = (b.getX() - a.getX())*(c.getY() - a.getY()) - (c.getX() - a.getX())*(b.getY()-a.getY());
      if (f < 0) { return -1; } 
      if (f > 0) { return 1; }
      return 0;
   }
 
-  public int immediateCCW(Point parent, Point child, Point v1, Point v2) {
+  public static int immediateCCW(Point parent, Point child, Point v1, Point v2) {
     // returns 1 if v1 is more immediate CCW of parent, child than v2
     // returns -1 if v2 is more immediate CCW of parent, child than v1 
     if (CCW(parent, child, v1) > CCW(parent, child, v2)) { return 1; }
     if (CCW(parent, child, v1) < CCW(parent, child, v2)) { return -1; }
     return CCW(parent, v1, v2);
   }
 
+
+
 }

main/HalfEdge.pde

@@ -10,6 +10,76 @@ public class HalfEdge {
 
   public HalfEdge(){}
 
+  public HalfEdge(Point p, Point q) {
+    // SETS THE TWIN
+    settwin(new HalfEdge());
+    twin.settwin(this);
+    // SETS THE ORIGIN
+    setOrigin(p);
+    twin.setOrigin(q);
+    // SETS THE COUNTED
+    setCounted(false);
+    twin.setCounted(false);
+
+    // MAGIC METHOD
+    connect();
+    twin.connect();
+
+
+
+
+  }
+
+  public int connect() {
+    ArrayList<HalfEdge> others = origin.getEntering();
+    if (others == null) { 
+      this.setprevious(gettwin());
+      gettwin().setnext(this);
+      // update vertex
+      return 0;
+    }
+    if (others.size() == 1) {
+      HalfEdge other = others.get(0);
+      this.setprevious(other.gettwin());
+      gettwin().setnext(other);
+      // no update vertex
+      return 1;
+    }
+    return complex(this, others); 
+  }
+
+
+  public int complex (HalfEdge self, ArrayList<HalfEdge> entering) {
+    Point parent = self.getOrigin();
+    Point child = self.gettwin().getOrigin();
+    Point p1;
+    Point p2;
+    int num = entering.size();
+    int[] chart = new int[num];
+    for (int i = 0; i < num; i++) {
+      p1 = entering.get(i).getOrigin();
+      p2 = entering.get((i+1)%num).getOrigin();
+      if (CompGeo.immediateCCW(parent, child, p1, p2) == 1) { chart[i]++; } 
+      else { chart[(i+1)%num]++; }
+    }
+    int Loser = 0;
+    int Winner = 0;
+    for (int i = 0; i < num; i++) {
+      if (chart[i] == 0) { Loser = i; }
+      if (chart[i] == 2) { Winner = i; }
+    }
+    self.setprevious(entering.get(Winner));
+    entering.get(Winner).setnext(self);
+    self.gettwin().setnext(entering.get(Loser).gettwin());
+    entering.get(Loser).gettwin().setprevious(self.gettwin());
+    return 2;
+  }
+
+
+
+
+
+
   public int count() {
     if (counted == false) {
       counted = true;
@@ -29,29 +99,42 @@ public class HalfEdge {
    }
   }
 
-  public ArrayList<HalfEdge> getHalfEdgesAlsoLeaving() {
-    ArrayList<HalfEdge> result = new ArrayList<HalfEdge>();
-    result.add(this);
+  public ArrayList<Point> getAdjacentPoints() {
+    ArrayList<Point> points = new ArrayList<Point>();
     HalfEdge temp = previous.gettwin();
     while (temp != this) {
-       result.add(temp);
-       temp = (temp.getprevious()).gettwin();
+      points.add(temp.gettwin().getOrigin());
+      temp = temp.getprevious().gettwin();
     }
-    return result;
+    points.add(this.getOrigin());
+    return points;
   }
 
-  public ArrayList<HalfEdge> getFace() {
+  public ArrayList<HalfEdge> getEntering() {
     ArrayList<HalfEdge> result = new ArrayList<HalfEdge>();
-    result.add(this);
-    HalfEdge temp = next;
-    while (temp != this) {
+    HalfEdge temp = twin.getnext().gettwin();
+    while (temp != twin) {
       result.add(temp);
-      temp = temp.getnext();
+      temp = temp.getnext().gettwin();
     }
-    return result; 
+    result.add(twin);
+    return result;
   }
 
-
+  public ArrayList<HalfEdge> getOtherLeaving() {
+    ArrayList<HalfEdge> result = new ArrayList<HalfEdge>();
+    HalfEdge temp = previous.gettwin();
+    while (temp != this) {
+       result.add(temp);
+       temp = (temp.getprevious()).gettwin();
+    }
+    return result;
+  }
+  public ArrayList<HalfEdge> getAllLeaving() {
+    ArrayList<HalfEdge> others = getOtherLeaving();
+    others.add(this);
+    return others;
+  }
 
   // may not want getters, but for now they are here.
   public void setprevious(HalfEdge p) {

main/Point.pde

@@ -28,6 +28,19 @@ public class Point {
     return ((a == x) && (b == y));
   }
 
+  public ArrayList<HalfEdge> getLeaving() {
+    if (ref == null) { return null; }
+    return ref.getAllLeaving();
+  }
+
+  public ArrayList<Point> getAdjacentPoints() {
+    if (ref == null) { return null; }
+    return ref.getAdjacentPoints();
+  }
+
+  public ArrayList<HalfEdge> getEntering() {
+    if (ref == null) { return null; }
+    return ref.getEntering();
+  }
 
-  // NEED METHOD GETTING ALL EDGES LEAVING POINT
 }