Sprite multiplexing
Encyclopedia
Sprite multiplexing is a computer graphics technique. It is mainly applicable to older video graphics hardware and computer systems.
Some video graphics hardware is capable of displaying sprites
. Depending on the hardware, there is a finite limit on the number of sprites that may be displayed by the hardware per frame, or per scanline. Sprites are most commonly utilised to output the display of video games, but there are also other applications.
The sprite multiplexing technique is based on the idea that before the video hardware displays the next frame, the computer program will program the hardware to display those sprites that are first to be displayed. After those sprites have been displayed, the program then reprograms the hardware to display the remaining sprites. That way, the number of sprites that appear on the screen may be doubled, or increased even more.
The programmer must carefully consider the layout of the screen. If the video graphics hardware is not reprogrammed in time for the extra sprites to be displayed, they will not appear.
The technique relies on the program being able to identify what part of the screen is being drawn at the moment, or being triggered by the video hardware to run a subroutine at the crucial moment.
Computers that allowed the programmer to employ the sprite multiplexing technique include:
Modern video graphics hardware typically does not use hardware sprites, since modern computer systems do not have the kind of memory bandwidth limitations that sprite hardware is designed to circumvent.
Some video graphics hardware is capable of displaying sprites
Sprite (computer graphics)
In computer graphics, a sprite is a two-dimensional image or animation that is integrated into a larger scene...
. Depending on the hardware, there is a finite limit on the number of sprites that may be displayed by the hardware per frame, or per scanline. Sprites are most commonly utilised to output the display of video games, but there are also other applications.
The sprite multiplexing technique is based on the idea that before the video hardware displays the next frame, the computer program will program the hardware to display those sprites that are first to be displayed. After those sprites have been displayed, the program then reprograms the hardware to display the remaining sprites. That way, the number of sprites that appear on the screen may be doubled, or increased even more.
The programmer must carefully consider the layout of the screen. If the video graphics hardware is not reprogrammed in time for the extra sprites to be displayed, they will not appear.
The technique relies on the program being able to identify what part of the screen is being drawn at the moment, or being triggered by the video hardware to run a subroutine at the crucial moment.
Computers that allowed the programmer to employ the sprite multiplexing technique include:
- Commodore Amiga
- Commodore 64Commodore 64The Commodore 64 is an 8-bit home computer introduced by Commodore International in January 1982.Volume production started in the spring of 1982, with machines being released on to the market in August at a price of US$595...
- MSXMSXMSX was the name of a standardized home computer architecture in the 1980s conceived by Kazuhiko Nishi, then Vice-president at Microsoft Japan and Director at ASCII Corporation...
Modern video graphics hardware typically does not use hardware sprites, since modern computer systems do not have the kind of memory bandwidth limitations that sprite hardware is designed to circumvent.