From 25b90203f0fb99c2ef80671b4e15e4880ee948cf Mon Sep 17 00:00:00 2001
From: JimmyBoivie <jimmy@JimmyBoivies-MacBook-Pro.local>
Date: Sat, 5 Dec 2015 20:42:51 -0500
Subject: [PATCH] signed area function

---
 main/CompGeo.pde  | 17 +++++++++++++++++
 main/FaceList.pde |  4 ++--
 main/HalfEdge.pde | 11 +++++++++++
 3 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/main/CompGeo.pde b/main/CompGeo.pde
index cc8bcf5..bb7bef0 100644
--- a/main/CompGeo.pde
+++ b/main/CompGeo.pde
@@ -50,4 +50,21 @@ public static class CompGeo {
     if ((nis % 2) == 0) { return false; }
     else { return true; }
   }
+  
+  public static float signedArea(HalfEdge h) {
+    return signedArea(h.getPointsNext()); 
+  }
+  
+  public static float signedArea(ArrayList<Point> points) {
+    int num = points.size();
+    Point p = null;
+    Point q = null;
+    float sum = 0;
+    for (int i = 0; i < num; i++) {
+      p = points.get(i);
+      q = points.get((i+1)%num);
+      sum += (p.getX()*q.getY() - q.getX()*p.getY());
+    }
+    return sum;
+  }
 }
\ No newline at end of file
diff --git a/main/FaceList.pde b/main/FaceList.pde
index e49033e..fe30fc9 100644
--- a/main/FaceList.pde
+++ b/main/FaceList.pde
@@ -4,8 +4,8 @@ public class FaceList {
   private Face unboundFace;
   
   public FaceList() {
-    faces = new ArrayList<Face>();
-    unboundFace = new Face();
+    //faces = new ArrayList<Face>();
+    //unboundFace = new Face();
   }
   
   public ArrayList<Face> getFaces() {
diff --git a/main/HalfEdge.pde b/main/HalfEdge.pde
index 6ec6181..55982c7 100644
--- a/main/HalfEdge.pde
+++ b/main/HalfEdge.pde
@@ -278,6 +278,17 @@ 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());
+    HalfEdge temp = this.getnext();
+    while (temp != this) {
+      points.add(temp.getOrigin());
+      temp = temp.getnext();
+    }
+    return points;
+  }
+  
   public HalfEdge gettwin() {
     return twin;
   }