Background drawing with parallax sprites.

With the introduction of a background image, I wanted to make it more robust than simply drawing a background sprite. I also wanted the user to be able to define multiple background layers. Why stop at just backgrouds? I wanted to give the user a method of drawing a foreground as well. The answer to this design comes in the form of Parallax Drawing. In a nut shell it means that a sprite moves in relation to the camera or in our case, viewport. 

Instead of giving the game engine an api to make backgrounds or foregrounds, I wanted to let the game engine's base sprite management handle the drawing of these layers like there were just another sprite. The controlling application wouldn't want to use these as collidables as it would create adverse affects and hinder character movement. The parallax sprites move in opposite relationship to the viewport. We must, however, provide a speed. We want foreground images to move faster past our view than the background.

See the video below for a demonstration of both parallax drawing and binding our viewport to the world.

You can see that the foreground moves faster than the background. When link hits the right edge of the world, the viewport stops. Obviously in a real game, the viewport would be locked to link. Usually placing him in the center of the screen or some buffer from the left and right edges. This is simply a test.