store right vector on the camera

Cameras/Camera.cs

@@ -10,6 +10,7 @@ namespace Kav
         public Vector3 Position { get; }
         public Vector3 Forward { get; }
         public Vector3 Up { get; }
+        public Vector3 Right { get; }
 
         public float FieldOfView { get; }
         public float AspectRatio { get; }
@@ -28,6 +29,7 @@ namespace Kav
             Position = position;
             Forward = forward;
             Up = up;
+            Right = Vector3.Cross(forward, up);
             View = Matrix.CreateLookAt(Position, Position + Forward, Up);
 
             FieldOfView = fieldOfView;