Organisation eines Z-Puffer-Etikettenspeichers

摘要

A method and system are provided for clearing portions of a Z-buffer in a computer controlled imaging system having an array of pixels, a graphics controller, a frame buffer and a Z-buffer. Invalidity bits (Z-tags) are established for each Z-buffer element in the Z-buffer and determine a valid or invalid state for the corresponding Z-buffer element. The invalidity bits are provided in the Z-buffer and are organized so that each invalidity bit is located on the same page as the corresponding Z-buffer element. Binary information is written into the invalidity bits so as to invalidate portions of the Z-buffer to be cleared. Additionally, accessing of the invalidity bits may be selectively discontinued so as to limit memory use when desired.