Line buffer system for displaying multiple images in a video game

A line buffer system for displaying a plurality of foreground objects and background on a monitor raster scan display screen used in a game to display a sequence of video pictures, each picture comprised of a plurality of parallel horizontal lines and each line being digitalized by division into adjacent pixels and each line being displayed on the display screen during active video scan, comprising:

• foreground memory means for storing object information in the form of blocks of digital data as foreground information in a foreground memory, each such block corresponding to a rectangular segment of the monitor screen displayable at a position on the screen that is selectable and changeable during the play of the game;
• background memory means for storing background information in the form of blocks of digital data in a background memory, such blocks corresponding to selectable and changeable rectangular locations on the monitor screen;
• buffer means;
• transfer means for transferring sufficient foreground information to comprise a horizontal line on the monitor screen from said foreground memory means to said buffer means during active video scan of a picture containing said line, but prior to the time active video scan of said line on the screen has begun;
• control means including means capable of controlling the intensity of the raster display in accordance with said data in said foreground memory means and said background memory means;
• and
• foreground output means for outputting said foreground information corresponding to said line from said buffer means in the form of a foreground data stream transmitted to said control means.