If you were to write directly to the screen when drawing a bouncing circle, you would run into some problems. Because you don’t do any buffering, your user might end up with a quarter circle drawn for a frame. This can be solved through Double Buffering, which means you draw the circle on to a backbuffer, then “flip” (or copy) the completed image on to the screen. This means you will only ever send a completely drawn scene to the monitor, but you will still have tearing issues.
