A visible element drawn in screen space. Overlays are useful for floating logos, heads up displays, and integrating user interfaces into the 3D window.

Initialize	Initializes the overlay with the specified x position, y position, width, and height, all specified in pixels.
InitializeWithPosAndSize	Initializes the overlay with the specified position and size.

Screen Overlays Overview  | IAgStkGraphicsTextureScreenOverlay