added method to check whether a point is inside the boundaries of a c…

…losed face
compgeogroup · Dec 5, 2015 · d0604f5 · d0604f5
1 parent 3e557e1
commit d0604f5
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Showing 2 changed files with 42 additions and 1 deletion.
diff --git a/main/CompGeo.pde b/main/CompGeo.pde
@@ -16,6 +16,41 @@ public static class CompGeo {
     return CCW(parent, v1, v2);
   }
 
+  private static boolean between(Point a, Point b, Point c) {
+    if (a.getX() > c.getX()) { return ((b.getX() > c.getX()) && (b.getX() < a.getX())); }
+    if (a.getX() < c.getX()) { return ((b.getX() < c.getX()) && (b.getX() > a.getX())); }
+    if (a.getY() > c.getY()) { return ((b.getY() > c.getY()) && (b.getY() < a.getY())); }
+    if (a.getY() < c.getY()) { return ((b.getY() < c.getY()) && (b.getY() > a.getY())); }
+    return false;
+  }
+
+  public static int intersect(Point a, Point b, Point c, Point d) {
+    if ((CCW(a,b,c) != CCW(a,b,d)) && ((CCW(c,d,a) != CCW(c,d,b)))) {
+      return 1;
+    }
+    if ((CCW(a,b,c) == 0) & (CCW(a,b,d) == 0)) {
+      if (between(a,c,b) || between(a,d,b) || between(c,a,d) || between(c,b,d)) {
+         return 1; 
+      }
+    }
+    return 0;
+  }
+
+  public static boolean inside(HalfEdge h, Point p, Point q) { 
+    HalfEdge temp = h.getnext();
+    Point e1 = h.getOrigin();
+    Point e2 = h.gettwin().getOrigin();
+    int nis = intersect(e1, e2, p, q);
+    while (temp != h) {
+      e1 = temp.getOrigin();
+      e2 = temp.gettwin().getOrigin();
+      nis += intersect(e1, e2, p, q);
+      temp = temp.getnext();
+    }
+    if ((nis % 2) == 0) { return false; }
+    else { return true; }
+  }
+
   // POINT-INSIDE-FACE METHOD SHOULD GOes here!
 
   // INTERSECTION METHOD

diff --git a/main/main.pde b/main/main.pde
@@ -16,13 +16,19 @@ public void setup() {
   list.addPoint(p4);
   Point p5 = new Point(200, 0);
   list.addPoint(p5);
+  Point p6 = new Point (-20, -40);
+  list.addPoint(p6);
+  Point p7 = new Point (10000,10000);
   DrawHalfEdge draw = new DrawHalfEdge();
   HalfEdge h1 = new HalfEdge(p1, p2);
   HalfEdge h2 = new HalfEdge(p1, p4);
   HalfEdge h3 = new HalfEdge(p3, p1);
   HalfEdge h4 = new HalfEdge(p1, p5);
   HalfEdge h5 = new HalfEdge(p3, p4);
-  h1.printFace();
+  h1.gettwin().printFace();
+  if (CompGeo.inside(h1.gettwin(), p6, p7)) {
+    System.out.println("INSIDE"); 
+  } else { System.out.println("OUTSIDE"); }
   //HalfEdge h5 = new HalfEdge(p5, p2);
   //h5.gettwin().printFace();
   //h5.printFace();