Added set view plane normal

include/Camera.hh

@@ -77,6 +77,8 @@ class vlCamera : public vlObject
   vlBooleanMacro(Switch,int);
 
   float GetTwist();
+  void SetViewPlaneNormal(float a[3]);
+  void SetViewPlaneNormal(float x,float y,float z);
   void CalcViewPlaneNormal();
   void CalcDistance();
   void CalcPerspectiveTransform();