Sprite (computer graphics) explained

In computer graphics, a sprite is a two-dimensional bitmap that is integrated into a larger scene, most often in a 2D video game. Originally, the term sprite referred to fixed-sized objects composited together, by hardware, with a background. Use of the term has since become more general.

Systems with hardware sprites include arcade video games of the 1970s and 1980s; game consoles including as the Atari VCS (1977), ColecoVision (1982), Famicom (1983), Genesis/Mega Drive (1988); and home computers such as the TI-99/4 (1979), Atari 8-bit computers (1979), Commodore 64 (1982), MSX (1983), Amiga (1985), and X68000 (1987). Hardware varies in the number of sprites supported, the size and colors of each sprite, and special effects such as scaling or reporting pixel-precise overlap.

Hardware composition of sprites occurs as each scan line is prepared for the video output device, such as a cathode-ray tube, without involvement of the main CPU and without the need for a full-screen frame buffer. Sprites can be positioned or altered by setting attributes used during the hardware composition process. The number of sprites which can be displayed per scan line is often lower than the total number of sprites a system supports. For example, the Texas Instruments TMS9918 chip supports 32 sprites, but only four can appear on the same scan line.

The CPUs in modern computers, video game consoles, and mobile devices are fast enough that bitmaps can be drawn into a frame buffer without special hardware assistance. Beyond that, GPUs can render vast numbers of scaled, rotated, antialiased, partially translucent, very high resolution images in parallel with the CPU.

Etymology

According to Karl Guttag, one of two engineers for the 1979 Texas Instruments TMS9918 video display processor, this use of the word sprite came from David Ackley, a manager at TI.[1] It was also used by Danny Hillis at Texas Instruments in the late 1970s.[2] The term was derived from the fact that sprites "float" on top of the background image without overwriting it, much like a ghost or mythological sprite.

Some hardware manufacturers used different terms, especially before sprite became common:

Player/Missile Graphics was a term used by Atari, Inc. for hardware sprites in the Atari 8-bit computers (1979) and Atari 5200 console (1982).[3] The term reflects the use for both characters ("players") and smaller associated objects ("missiles") that share the same color. The earlier Atari Video Computer System and some Atari arcade games used player, missile, and ball.

Stamp was used in some arcade hardware in the early 1980s, including Ms. Pac-Man.

Movable Object Block, or MOB, was used in MOS Technology's graphics chip literature. Commodore, the main user of MOS chips and the owner of MOS for most of the chip maker's lifetime, instead used the term sprite for the Commodore 64.

OBJs (short for objects) is used in the developer manuals for the NES, Super NES, and Game Boy. The region of video RAM used to store sprite attributes and coordinates is called OAM (Object Attribute Memory). This also applies to the Game Boy Advance and Nintendo DS.

History

Arcade video games

The use of sprites originated with arcade video games. Nolan Bushnell came up with the original concept when he developed the first arcade video game, Computer Space (1971). Technical limitations made it difficult to adapt the early mainframe game Spacewar! (1962), which performed an entire screen refresh for every little movement, so he came up with a solution to the problem: controlling each individual game element with a dedicated transistor. The rockets were essentially hardwired bitmaps that moved around the screen independently of the background, an important innovation for producing screen images more efficiently and providing the basis for sprite graphics.[4]

The earliest video games to represent player characters as human player sprites were arcade sports video games, beginning with Taito's TV Basketball,[5] [6] [7] released in April 1974 and licensed to Midway Manufacturing for release in North America.[8] Designed by Tomohiro Nishikado, he wanted to move beyond simple Pong-style rectangles to character graphics, by rearranging the rectangle shapes into objects that look like basketball players and basketball hoops.[9] [10] Ramtek released another sports video game in October 1974, Baseball,[8] which similarly displayed human-like characters.[11]

The Namco Galaxian arcade system board, for the 1979 arcade game Galaxian, displays animated, multi-colored sprites over a scrolling background.[12] It became the basis for Nintendo's Radar Scope and Donkey Kong arcade hardware and home consoles such as the Nintendo Entertainment System.[13] According to Steve Golson from General Computer Corporation, the term "stamp" was used instead of "sprite" at the time.[14]

Home systems

Signetics devised the first chips capable of generating sprite graphics (referred to as objects by Signetics) for home systems. The Signetics 2636 video processors were first used in the 1978 1292 Advanced Programmable Video System and later in the 1979 Elektor TV Games Computer.

The Atari VCS, released in 1977, has a hardware sprite implementation where five graphical objects can be moved independently of the game playfield. The term sprite was not in use at the time. The VCS's sprites are called movable objects in the programming manual, further identified as two players, two missiles, and one ball.[15] These each consist of a single row of pixels that are displayed on a scan line. To produce a two-dimensional shape, the sprite's single-row bitmap is altered by software from one scan line to the next.

The 1979 Atari 400 and 800 home computers have similar, but more elaborate, circuitry capable of moving eight single-color objects per scan line: four 8-bit wide players and four 2-bit wide missiles. Each is the full height of the display - a long, thin strip. DMA from a table in memory automatically sets the graphics pattern registers for each scan line. Hardware registers control the horizontal position of each player and missile. Vertical motion is achieved by moving the bitmap data within a player or missile's strip. The feature was called player/missile graphics by Atari.

Texas Instruments developed the TMS9918 chip with sprite support for its 1979 TI-99/4 home computer. An updated version is used in the 1981 TI-99/4A.

Systems with hardware sprites

These are base hardware specs and do not include additional programming techniques, such as using raster interrupts to repurpose sprites mid-frame.

! System !! Sprite hardware !! Introduced!! Sprites on screen !! Sprites per scan line !! Max. texels on line !! Texture width !! Texture height !! Colors !! Zoom !! Rotation !! Collision detection !! Transparency !! Source
1990 16 16 ? 16 16 15 [16]
1977 5 5 19 1, 8 262 1 Color key [17]
1979 8 8 40 2, 8 128, 256 1 Color key [18]
1982 8 8 96, 192 12, 24 21 1, 3 Color key [19]
1985 8, can be reused horizontally per 4 pixel increments Arbitrary, 8 unique Arbitrary 16 Arbitrary 3, 15 list Color key [20]
1992 8, can be reused horizontally per 2 pixel increments Arbitrary, 8 unique Arbitrary 16, 32, 64 Arbitrary 3, 15 Color key
TMS9918A1983324648, 168, 161Color key
TMS99181979324648, 168, 161Color key
Gameduino 2011 256 96 1,536 16 16 255 Color key [21]
STIC AY-3-8900 1979 8 8 64 8 8,16 1 Color key [22]
TMS9918A1983324648, 168, 161Color key [23]
1986 32 8 128 8, 16 8,16 1, 3, 7, 15 per line Color key
1988 32 8 128 8,16 8,16 1, 3, 7, 15 per line Color key
Namco Pac-Man
(arcade) 		TTL 1980 6 6 96 16 16 3 Color key [24]
HuC6270A 1987 64 16 256 16, 32 16, 32, 64 15 Color key [25]
Namco Galaxian
(arcade) 		TTL1979 7 7 112 16 16 3 Color key [26] [27] [28]
Nintendo Donkey Kong, Radar Scope
(arcade) 		1979 128 16 256 16 16 3 Color key [29]
Integrated PPU 2004 128 128 1,210 8, 16, 32, 64 8, 16, 32, 64 65,536 Color key, blending [30]
1983 64 8 64 8 8, 16 3 Color key [31]
Integrated PPU 1989 40 10 80 8 8, 16 3 Color key [32]
Integrated PPU 2001 128 128 1210 8, 16, 32, 64 8, 16, 32, 64 15, 255Color key, blending [33]
YM2602B VDP
(TMS9918-derived) 		1985 64 8 128 8, 16 8, 16 15 Color key [34] [35]
YM7101 VDP
(SMS VDP-derived) 		1988 80 20 320 8, 16, 24, 32 8, 16, 24, 32 15 Color key [36] [37]
Sega OutRun (arcade) 1986 128 128 1600 8 to 512 8 to 256 15 Alpha [38] [39] [40] [41] [42] [43] [44]
Cynthia jr. (original), Cynthia (later models) 1987 128 32 512 16 16 15 Color key [45] [46] [47]
LSPC2-A2 1990 384 96 1536 16 16 to 512 15 Color key [48] [49] [50]
S-PPU1, S-PPU2 1990 128 34 2568, 16, 32, 64 8, 16, 32, 64 15 Color key, averaging [51]
System Sprite hardware Introduced Sprites on screen Sprites on line Max. texels on line Texture width Texture height Colors Hardware zoom Transparency Source

See also

Notes and References

  1. Web site: Guttag . KArl . First, Be Useful (Home computers and Pico Projectors) . KGOnTech . December 6, 2011.
  2. Book: Johnstone . Bob . Never Mind the Laptops: Kids, Computers, and the Transformation of Learning . 2003 . 978-0595288427 . 108 . iUniverse .
  3. Web site: De Re Atari. 1981. 2017-08-10. 2017-07-31. https://web.archive.org/web/20170731041803/http://www.atariarchives.org/dere/chapt04.php. live.
  4. Book: Swalwell . Melanie . Wilson . Jason . The Pleasures of Computer Gaming: Essays on Cultural History, Theory and Aesthetics . 12 May 2015 . . 978-0-7864-5120-3 . 109–10 . 16 May 2021 . 16 May 2021 . https://web.archive.org/web/20210516025657/https://books.google.com/books?id=BbW_DUV-pP4C&pg=PA110 . live .
  5. Book: Colby . Richard . Johnson . Matthew S. S. . Colby . Rebekah Shultz . The Ethics of Playing, Researching, and Teaching Games in the Writing Classroom . 27 January 2021 . . 978-3-030-63311-0 . 130 . 3 May 2021 . 3 May 2021 . https://web.archive.org/web/20210503195104/https://books.google.com/books?id=vZoXEAAAQBAJ&pg=PA130 . live .
  6. http://allincolorforaquarter.blogspot.co.uk/2013/11/video-game-firsts.html Video Game Firsts
  7. http://flyers.arcade-museum.com/?page=wide-flyer&db=videodb&id=4036&image=2 Basketball Flyer
  8. Book: Akagi . Masumi . アーケードTVゲームリスト国内•海外編(1971-2005) . Arcade TV Game List: Domestic • Overseas Edition (1971-2005) . 13 October 2006 . Amusement News Agency . ja . Japan . 978-4990251215 . 40-1, 51, 129 .
  9. Book: Smith . Alexander . They Create Worlds: The Story of the People and Companies That Shaped the Video Game Industry, Vol. I: 1971-1982 . 19 November 2019 . . 978-0-429-75261-2 . 191–95 . 16 May 2021 . 2 May 2021 . https://web.archive.org/web/20210502064515/https://books.google.com/books?id=Cxy_DwAAQBAJ&pg=PT191 . live .
  10. News: スペースインベーダー・今明かす開発秘話――開発者・西角友宏氏、タイトー・和田洋一社長対談 . Space Invader, Development Secret Story Revealed Now―Interview With Developer Tomohiro Nishikado, Taito President Yoichi Wada . 3 May 2021 . . March 21, 2008 . ja . dead . https://web.archive.org/web/20080323064622/http://trendy.nikkeibp.co.jp/article/special/20080318/1008218/ . March 23, 2008.
  11. Thorpe . Nick . The 70s: The Genesis of an Industry . . March 2014 . 127 . 24–7 .
  12. Book: Dillon, Roberto. The Golden Age of Video Games: The Birth of a Multibillion Dollar Industry. 19 April 2016. CRC Press. 9781439873243. Google Books.
  13. https://web.archive.org/web/20120505103737/http://www.glitterberri.com/developer-interviews/how-the-famicom-was-born/making-the-famicom-a-reality/ Making the Famicom a Reality
  14. Steve Golson . 2016 . Classic Game Postmortem: 'Ms. Pac-Man' . Conference . en . 2017-01-26 . 20:30 . . […] 6 moving characters, what you would call today "sprites" we called them "stamps" back then, […]..
  15. Web site: Wright. Steve. Stella Programmer's Guide. December 3, 1979. April 14, 2016. March 27, 2016. https://web.archive.org/web/20160327103553/http://atarihq.com/danb/files/stella.pdf. live.
  16. Web site: Plus - CPCWiki . Cpcwiki.eu . 2009-11-29 . 2011-07-20 . https://web.archive.org/web/20110720154941/http://cpcwiki.eu/index.php/Plus . live .
  17. Web site: Television Interface Adaptor . AtariArchives.com . 2011-02-06 . 2010-08-25 . https://web.archive.org/web/20100825163151/http://www.atariarchives.org/dev/tia/description.php . live .
  18. Web site: Atari 5200 FAQ - Hardware Overview . AtariHQ.com . 2011-02-06 . 2011-05-14 . https://web.archive.org/web/20110514110844/http://www.atarihq.com/5200/5200faq/04_02.html . live .
  19. Web site: The MOS 6567/6569 video controller (VIC-II) and its application in the Commodore 64 . 2006-01-08 . bot: unknown . https://web.archive.org/web/20060830024142/http://www.minet.uni-jena.de/~andreasg/c64/vic_artikel/vic_article_1.htm . August 30, 2006 .
  20. Web site: Amiga Hardware Reference Manual 4: sprite hardware . 1989 . 2017-05-23 . 2017-08-14 . https://web.archive.org/web/20170814170220/http://amigadev.elowar.com/read/ADCD_2.1/Hardware_Manual_guide/node00AE.html . live .
  21. Web site: Gameduino Specifications . excamera.com . 2011-06-13 . 2021-12-13 . https://web.archive.org/web/20211213052910/https://excamera.com/sphinx/gameduino3/ . live .
  22. Web site: STIC - Intellivision Wiki. wiki.intellivision.us. 15 March 2018. 9 July 2018. https://web.archive.org/web/20180709215702/http://wiki.intellivision.us/index.php?title=STIC. live.
  23. Book: TEXAS INSTRUMENTS 9900: TMS9918A/TMS9928AITMS9929A Video Display Processors . 2011-07-05 . 2017-08-14 . https://web.archive.org/web/20170814231446/https://emu-docs.org/VDP%20TMS9918/Datasheets/TMS9918.pdf . dead .
  24. Book: Racing the Beam: The Atari Video Computer System. Nick. Montfort. Ian. Bogost. 9 January 2009. MIT Press. 9780262261524. Google Books.
  25. Web site: Learn Multi platform 6502 Assembly Programming... For Monsters! Platform Specific Series. 2021-12-04. 2021-12-04. https://web.archive.org/web/20211204193150/https://www.chibiakumas.com/6502/platform4.php#LessonP33. live.
  26. Web site: Galaxian-derived video hardware . . . October 23, 2018 . November 30, 2017 . https://web.archive.org/web/20171130235821/https://github.com/mamedev/mame/blob/master/src/mame/video/galaxian.cpp . live .
  27. Web site: Galaxian-derived hardware . . . October 23, 2018 . September 5, 2018 . https://web.archive.org/web/20180905051639/https://github.com/mamedev/mame/blob/master/src/mame/drivers/galaxian.cpp . live .
  28. Web site: Galaxian hardware family . . . October 23, 2018 . February 24, 2021 . https://web.archive.org/web/20210224150309/https://github.com/mamedev/mame/blob/master/src/mame/includes/galaxian.h . live .
  29. Nathan Altice (2015), I Am Error: The Nintendo Family Computer / Entertainment System Platform, pages 53 & 69, MIT Press
  30. Web site: Specifications . Nocash.emubase.de . 2009-11-29 . dead . https://web.archive.org/web/20090621131721/http://nocash.emubase.de/gbatek.htm#dstechnicaldata . 2009-06-21 .
  31. Web site: Microsoft Word - NESDoc.doc . 2009-11-29 . 2011-09-30 . https://web.archive.org/web/20110930163140/http://nesdev.parodius.com/NESDoc.pdf . live .
  32. Web site: GameBoy - Spielkonsolen Online Lexikon . At-mix.de . 2004-06-22 . 2009-11-29 . 2010-05-06 . https://web.archive.org/web/20100506132321/http://www.at-mix.de/gameboy.htm . live .
  33. Web site: Specifications . Nocash.emubase.de . 2009-11-29 . dead . https://web.archive.org/web/20090621131721/http://nocash.emubase.de/gbatek.htm . 2009-06-21 .
  34. Web site: Sega Master System VDP documentation . Charles MacDonald . 2011-07-05 . https://web.archive.org/web/20140318183214/http://cgfm2.emuviews.com/txt/msvdp.txt . 2014-03-18.
  35. Web site: Sega Master System Technical Information . TXT . Smspower.org . 2016-11-28 . 2019-06-24 . https://web.archive.org/web/20190624130810/http://www.smspower.org/uploads/Development/richard.txt . live .
  36. Web site: Sega Programming FAQ October 18, 1995, Sixth Edition - Final . 2015-12-10 . dead . https://web.archive.org/web/20050122094914/http://fly.hiwaay.net/~jfrohwei/sega/genesis.html . January 22, 2005 .
  37. Web site: Staff . Polygon . How Sega built the Genesis . Polygon . 2015-02-03 . 2016-11-28 . 2015-11-03 . https://web.archive.org/web/20151103090922/http://www.polygon.com/features/2015/2/3/7952705/sega-genesis-masami-ishikawa . live .
  38. Web site: Sega Out Run Hardware (Sega) . System 16 . 2016-03-31 . 2016-11-28 . 2016-11-28 . https://web.archive.org/web/20161128203655/http://system16.com/hardware.php?id=697 . live .
  39. Web site: mame/segaorun.c at master · mamedev/mame · GitHub. https://archive.today/20141121130850/https://github.com/mamedev/mame/blob/master/src/mame/drivers/segaorun.c. dead. 21 November 2014. 21 November 2014. github.com. 15 March 2018.
  40. Web site: Out Run . https://web.archive.org/web/20010227042525/http://emustatus.rainemu.com/games/outrun.htm . dead . 2001-02-27 . 2001-02-27 . 2016-11-28.
  41. Web site: Out Run Hardware (Sega) . System 16 . 2009-11-29 . 2016-11-28 . https://web.archive.org/web/20161128203655/http://system16.com/hardware.php?id=697 . live .
  42. Web site: Version 0.3 - 7th February 1998 . Coinop.org . 2016-11-28 . 2016-05-14 . https://web.archive.org/web/20160514060702/http://www.coinop.org/kb_dl.aspx/KB/faqs/faq-sega%20outrun.html . live .
  43. Web site: Sega 16-bit common hardware . 2016-02-09 . dead . https://web.archive.org/web/20160125144902/http://imame4all.googlecode.com/svn-history/r146/Reloaded/trunk/src/mame/video/segaic16.c . 2016-01-25 .
  44. Web site: Sega "X-Board" hardware notes . https://web.archive.org/web/20140318183606/http://cgfm2.emuviews.com/txt/loftech.txt . dead . 2014-03-18 . TXT . 2016-11-28.
  45. Web site: X68000-Computer Museum . Museum.ipsj.or.jp . 2016-11-28 . 2014-10-02 . https://web.archive.org/web/20141002234300/http://museum.ipsj.or.jp/en/computer/personal/0038.html . live .
  46. Web site: mame/x68k.c at master · mamedev/mame · GitHub. https://archive.today/20141121130816/https://github.com/mamedev/mame/blob/master/src/mess/video/x68k.c. dead. 21 November 2014. 21 November 2014. github.com. 15 March 2018.
  47. Web site: Yoshida. Koichi. 超連射68K 開発後記. Yosshin's web page. 12 September 2001. 2016-11-28. ja. https://web.archive.org/web/20190512090239/http://www2.tky.3web.ne.jp/~yosshin/my_works/postmortem.html. 12 May 2019. live. (Translation by Shmuplations.).
  48. Web site: Neo-Geo MVS Hardware Notes . TXT . Furrtek.free.fr . 2016-11-28 . 2018-09-16 . https://web.archive.org/web/20180916101030/http://furrtek.free.fr/noclass/neogeo/mvstech.txt . live .
  49. Web site: Neo-Geo Programming Manual . Furrtek.free.fr . 2016-11-28 . 2016-12-06 . https://web.archive.org/web/20161206012848/http://furrtek.free.fr/noclass/neogeo/NeoGeoPM.pdf . live .
  50. Web site: Big List of Debug Dipswitches . Neo-Geo . 2014-07-09 . 2016-11-28 . 2016-11-28 . https://web.archive.org/web/20161128134201/http://www.neo-geo.com/wiki/index.php?title=Neo-Geo_Big_List_of_Debug_Dipswitches . live .
  51. Web site: snes sprite engine design guide. 30 March 2021 . https://web.archive.org/web/20211204193150/https://megacatstudios.com/blogs/retro-development/snes-sprite-engine-design-guidelines . 2021-12-04 .

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