Fast and Simple Occlusion Culling

In many graphics applications, such as building walkthroughs and first-person games, the user moves around the interior of a virtual environment and the computer creates an image for each location of the user. For any given position, the user typically sees only a small fraction of the scene. Thus to speed up the image rendering, an application should avoid drawing the primitives in the environment that the user cannot see. There are several classes of algorithms to determine which primitives should be ignored, or culled. Back-face culling algorithms determine those primitives that face away from the user. View frustum culling determines the primitives that lie outside of the user's field of view. Occlusion culling determines the primitives that are occluded by other primitives.