public Game1()
        {
            graphics = new GraphicsDeviceManager(this);
            Content.RootDirectory = "Content";

            billboardGC = new BillboardGC(this);
            Components.Add(billboardGC);
        }
        public Game1()
        {
            graphics = new GraphicsDeviceManager(this);
            Content.RootDirectory = "Content";

            //switch the 2 lines below to change camera mode
            //GameComponent camComponent = new QuakeCameraGC(this);
            GameComponent camComponent = new QuatCamGC(this);

            GameComponent billComponent = new BillboardGC(this);

            camComponent.UpdateOrder  = 0;
            billComponent.UpdateOrder = 1;

            Components.Add(camComponent);
            Components.Add(billComponent);
        }