Compute the normal of a triangle.

Co-authored-by: sigonasr2 <sigonasr2@gmail.com>

src/sig/SigRenderer.java

@@ -17,8 +17,9 @@ public class SigRenderer implements MouseListener,MouseMotionListener{
     }
 
     SigRenderer(JFrame f) {
-        tri = new Triangle(new Vector3d(),new Vector3d(),new Vector3d());
+        tri = new Triangle(new Vector3d(-1,-1,0),new Vector3d(1,0,0),new Vector3d(0,2,0));
         System.out.println(tri);   
+        System.out.println(tri.getNormal()); 
 
         Panel p = new Panel();
 

src/sig/Triangle.java

@@ -12,4 +12,15 @@ public class Triangle {
     public String toString() {
         return "Triangle [A=" + A + ", B=" + B + ", C=" + C + "]";
     }
+
+    public Vector3d getNormal() {
+        Vector3d AB = (Vector3d)A.clone();
+        AB.sub(B);
+        Vector3d BC = (Vector3d)B.clone();
+        BC.sub(C);
+        Vector3d crossP = new Vector3d();
+        crossP.cross(AB,BC);
+        crossP.normalize();
+        return crossP;
+    }
 }