DEVICE FOR QUICK ERASING OF THE DISPLAY SCREEN OF A COMPUTER, PARTICULARLY FOR CREATING MOVIE IMAGES

摘要

To reduce the time interval between frames in a computer animation system the display memory is not cleared between frames. The display system has a first full screen bitmapped display memory 13, 14 and a second memory 17, 18. The second memory 17, 18 holds, for each pixel in 13, 14, the number of the frame that that particular pixel appears in. Thus only those pixels relating to frame O are read out during frame O, etc., and rather than clearing the display memory data can be overwritten because the frame numbers in the second memory 17, 18 will prevent the production of spacious images. A similar system (Fig 2) is used in a windowing system. IMAGE