MEMORY MANAGEMENT FOR SYSTEMS FOR GENERATING 3-DIMENSIONAL COMPUTER IMAGES

Memory management system and method for use with systems for generating 3-dimensional computer generated images are provided. The system includes a) a device for subdividing the image into rectangular areas, b) a memory for storing object data for each rectangular area and depth data derived from the object data, c) a device for storing the object data in the memory, d) a device for deriving the depth data for each rectangular area from the object data, e) a device for storing the depth data for each rectangular area in the memory, f) a device for loading further object data into the memory to replace part of the existing contents, g) a device for retrieving the stored depth data, h) a device for deriving updated depth data for each picture element of each rectangular area from the new object and stored depth data, and storing the updated depth data to replace the previously stored depth data, i) a device for causing features e), f), g) and h) to repeatedly perform the functions until there is no further object data to load to the 1 memory, and j) a device for deriving image data and shading data from the depth data for display.