In this form of texture mapping, three sizes of each texture map are made, a large, a medium and a small version. In essence, it replaces the appearance of an object with a more detailed image as you move closer to the object in the game. The system loads the texture maps for the object. Based on the size, it decides which two texture maps to use. For our example, it might choose the medium and small texture maps.
Environment mapping is no less amazing.
Simple in concept, it means that reflections of objects are rendered and mapped onto the reflecting surface. The sheer amount of calculating that is done by the graphics processor to determine the angle and transparency for each reflected object, and then render it in real time, is extraordinary. An incredible number of calculations have to happen for every single polygon in a game. The games come on proprietary ROMs housed in plastic cartridges. You interact with the game via the controller .