comp geo class to have some useful functions

main/CompGeo.pde

@@ -0,0 +1,16 @@
+public static class CompGeo {
+
+  public int CCW(Vertex a, Vertex b, Vertex 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(Vertex parent, Vertex child, Vertex v1, Vertex v2) {
+    if (CCW(parent, child, v1) > CCW(parent, child, v2)) { return 1; }
+    return CCW(parent, v1, v2);
+  }
+
+}