magic maybe?

main/CompGeo.pde

@@ -68,6 +68,77 @@ public static class CompGeo {
     return sum;
   }
 
+  public static boolean isContained(HalfEdge inner, HalfEdge outer, Point far) {
+    Point inHandle = inner.getOrigin();
+    return inside(outer, inHandle, far);
+  }
+
+
+
+
+  public static ArrayList findFriends(HalfEdge inner, HalfEdge outer, PointList points) {
+    ArrayList<HalfEdge> handles = points.getAllStructures();
+    ArrayList<HalfEdge> friends = new ArrayList<HalfEdge>();
+    int num = handles.size();
+    HalfEdge out = null;
+    for (int i = 0; i < num; i++) {
+      if (inner.canReach(handles.get(i))) { continue; }
+      out = findTightOuterBoundary(handles.get(i), points);
+      if (out == outer) {
+        if (signedArea(handles.get(i)) <= 0) { friends.add(handles.get(i).gettwin()); continue; }
+        else { friends.add(handles.get(i)); continue; }
+      }
+      if ((out != null) && (outer != null)) {
+        if (out.canReach(outer)) {
+           if (signedArea(handles.get(i)) <= 0) { friends.add(handles.get(i).gettwin()); continue; }
+           else { friends.add(handles.get(i)); continue; }
+        }
+      }
+    }
+    return friends;
+  }
+
+
+  public static HalfEdge findTightOuterBoundary(HalfEdge inner, PointList points) {
+    Point far = points.getFar();
+    ArrayList<HalfEdge> handles = points.getAllStructures();
+    int num = handles.size();
+    HalfEdge temp;
+    HalfEdge tightest = null;
+    for (int i = 0; i < num; i++) {
+      temp = handles.get(i);
+      if (inner.canReach(temp)) { continue; } // MAKE SURE DONT CHECK AGAINST ITSELF
+      if (isContained(inner, temp, far)) {
+        if (tightest == null) { 
+          tightest = temp; 
+        } else { 
+          if (isContained(temp, tightest, far)) {
+            tightest = temp;
+          }
+        }
+      }
+    }
+    tightest = findSuperTightBoundary(inner, tightest, far);  
+    tightest.reset();
+    return tightest;
+  }
+
+  public static HalfEdge findSuperTightBoundary(HalfEdge inner, HalfEdge outer, Point far) {
+    if (outer == null) { return null; }
+    if ((isContained(inner, outer, far)) && (signedArea(outer) < 0)) { return outer; }
+    if (outer.getCounted() == false) {
+      outer.setCounted(true);
+      HalfEdge temp = findSuperTightBoundary(inner, outer.getnext(), far);
+      if (temp != null) { return temp; }
+      temp = findSuperTightBoundary(inner, outer.getprevious(), far);
+      if (temp != null) { return temp; }
+      temp = findSuperTightBoundary(inner, outer.gettwin(), far);
+      if (temp != null) { return temp; }
+    }
+    return null;
+  }
+
+
 
 
 }

main/HalfEdge.pde

@@ -293,6 +293,7 @@ public class HalfEdge {
     return "Origin: " + origin.toString() + "\nDestination: " + twin.getOrigin().toString(); 
   }
 
+
   public ArrayList<Point> getPointsNext() {
     ArrayList<Point> points = new ArrayList<Point>();
     points.add(this.getOrigin());

main/Point.pde

@@ -11,10 +11,16 @@ public class Point {
   public float getX() {
      return x; 
   }
+  public void setX(float f) {
+     x = f; 
+  }
 
   public float getY() {
      return y; 
   }
+  public void setY(float f) {
+     y = f; 
+  }
 
   public HalfEdge getRef() {
      return ref;

main/PointList.pde

@@ -1,9 +1,15 @@
 public class PointList {
 
   private ArrayList<Point> points;
+  private Point far;
 
   public PointList() {
-    points = new ArrayList<Point>(); 
+    points = new ArrayList<Point>();
+    far = new Point(0, 10000);
+  }
+
+  public Point getFar() {
+    return far; 
   }
 
   public ArrayList<Point> getPoints() {
@@ -17,7 +23,10 @@ public class PointList {
 
 
   public void addPoint(Point p) {
-    points.add(p);  
+    points.add(p);
+    if (p.getY() > far.getY()) {
+      far.setY(p.getY() + 1); 
+    }
   }
 
   public boolean removePoint(Point p) {

main/main.pde

@@ -8,9 +8,9 @@ public void setup() {
   PointList list = new PointList();
   Point p1 = new Point(0, 0);
   list.addPoint(p1);
-  Point p2 = new Point(100, 200);
+  Point p2 = new Point(100, 50);
   list.addPoint(p2);
-  Point p3 = new Point(-100, -100);
+  Point p3 = new Point(-200, -50);
   list.addPoint(p3);
   Point p4 = new Point(0, 150);
   list.addPoint(p4);
@@ -24,13 +24,14 @@ public void setup() {
   HalfEdge h2 = new HalfEdge(p1, p4);
   HalfEdge h3 = new HalfEdge(p3, p1);
   HalfEdge h4 = new HalfEdge(p1, p5);
-  //HalfEdge h5 = new HalfEdge(p3, p4);
-  float f = CompGeo.signedArea(h2.gettwin());
-  float f2 = CompGeo.signedArea(h2);
+  HalfEdge h5 = new HalfEdge(p3, p4);
+  HalfEdge h6 = new HalfEdge(p2, p4);
+  float f = CompGeo.signedArea(h1.gettwin());
+  float f2 = CompGeo.signedArea(h1);
   System.out.println("Signed Area: " + f);
   System.out.println("Signed Area: " + f2);
   h1.gettwin().printFace();
-  h2.printFace();
+  h1.printFace();
   if (CompGeo.inside(h1.gettwin(), p6, p7)) {
     System.out.println("INSIDE"); 
   } else { System.out.println("OUTSIDE"); }