public MainPage()
      {
         InitializeComponent();

         totalElapsedTime = TimeSpan.FromSeconds(0.0);
         rotationSpeed = 2.0;

         // Create camera and models
         camera = new Camera((float)ds.Width / (float)ds.Height);
         Earth = new Earth();
         Sun = new Sun { IsVisible = false, Transform = Matrix.CreateTranslation(-4, 0, 0) };

         DataContext = this;
      }
        public MainPage()
        {
            InitializeComponent();

            totalElapsedTime = TimeSpan.FromSeconds(0.0);
            rotationSpeed    = 2.0;

            // Create camera and models
            camera = new Camera((float)ds.Width / (float)ds.Height);
            Earth  = new Earth();
            Sun    = new Sun {
                IsVisible = false, Transform = Matrix.CreateTranslation(-4, 0, 0)
            };

            DataContext = this;
        }