in many ways, 3D games are "lazy" where the rendering takes place in real time, with the code only hinting to what has to be rendered and how, but it is possible to reduce any 3D game to a "planar" one that achieves the same depth-effect; the computer screen is very much 2D and there is no "depth" that can be displayed, only an illusion thereof is created when shadows and texturing are correctly used,