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Incomputer graphics, asprite is atwo-dimensionalbitmap that is integrated into a larger scene, most often in a 2Dvideo game. Originally, the termsprite referred to fixed-sized objects composited together, by hardware, with a background.[1] Use of the term has since become more general.
Systems with hardware sprites includearcade video games of the 1970s and 1980s;game consoles including as theAtari VCS (1977),ColecoVision (1982),Famicom (1983),Genesis/Mega Drive (1988); andhome computers such as theTI-99/4 (1979),Atari 8-bit computers (1979),Commodore 64 (1982),MSX (1983),Amiga (1985), andX68000 (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 eachscan line is prepared for the video output device, such as acathode-ray tube, without involvement of the mainCPU and without the need for a full-screenframe buffer.[1] 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 InstrumentsTMS9918 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,anti-aliased, partially translucent, very high resolution images in parallel with the CPU.
According to Karl Guttag, one of two engineers for the 1979Texas Instruments TMS9918 video display processor, this use of the wordsprite came from David Ackley, a manager at TI.[2][3] It was also used byDanny Hillis at Texas Instruments in the late 1970s.[4] The term was derived from the fact that sprites "float" on top of the background image without overwriting it, much like a ghost ormythological sprite.
Some hardware manufacturers used different terms, especially beforesprite became common:
Player/Missile Graphics was a term used byAtari, Inc. for hardware sprites in theAtari 8-bit computers (1979) andAtari 5200 console (1982).[5] The term reflects the use for both characters ("players") and smaller associated objects ("missiles") that share the same color. The earlierAtari Video Computer System and some Atari arcade games usedplayer,missile, andball.
Stamp was used in some arcade hardware in the early 1980s, includingMs. Pac-Man.[6]
Movable Object Block, orMOB, was used inMOS 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 termsprite for the Commodore 64.
OBJs (short forobjects) is used in the developer manuals for theNES,Super NES, andGame Boy. The region ofvideo RAM used to store sprite attributes and coordinates is calledOAM (Object Attribute Memory). This also applies to theGame Boy Advance andNintendo DS.
The use of sprites originated witharcade 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 theearly mainframe gameSpacewar! (1962), which performed an entirescreen refresh for every little movement, so he came up with a solution to the problem: controlling each individual game element with a dedicatedtransistor. Therockets were essentially hardwiredbitmaps 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.[7]
The earliest video games to representplayer characters as human player sprites were arcadesports video games, beginning withTaito'sTV Basketball,[8][9][10] released in April 1974 and licensed toMidway Manufacturing for release in North America.[11] Designed byTomohiro Nishikado, he wanted to move beyond simplePong-style rectangles to character graphics, by rearranging the rectangle shapes into objects that look likebasketball players andbasketball hoops.[12][13]Ramtek released another sports video game in October 1974,Baseball,[11] which similarly displayed human-like characters.[14]
TheNamco Galaxianarcade system board, for the 1979 arcade gameGalaxian, displays animated, multi-colored sprites over a scrolling background.[15] It became the basis forNintendo'sRadar Scope andDonkey Kong arcade hardware andhome consoles such as theNintendo Entertainment System.[16] According to Steve Golson fromGeneral Computer Corporation, the term "stamp" was used instead of "sprite" at the time.[6]
Signetics devised the first chips capable of generating sprite graphics (referred to asobjects by Signetics) for home systems. The Signetics 2636 video processors were first used in the 19781292 Advanced Programmable Video System and later in the 1979Elektor TV Games Computer.
TheAtari VCS, released in 1977, has a hardware sprite implementation where five graphical objects can be moved independently of the game playfield. The termsprite was not in use at the time. The VCS's sprites are calledmovable objects in the programming manual, further identified as twoplayers, twomissiles, and oneball.[17] These each consist of a single row of pixels that are displayed on ascan 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 1979Atari 400 and 800 home computers have similar, but more elaborate, circuitry capable of moving eight single-color objects per scan line: four 8-bit wideplayers and four 2-bit widemissiles. 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 calledplayer/missile graphics by Atari.
Texas Instruments developed theTMS9918 chip with sprite support for its 1979 TI-99/4 home computer. An updated version is used in the 1981TI-99/4A.
Sprites remained popular with the rise of2.5D games (those which recreate a 3D game space from a 2D map) in the late 1980s and early 1990s. A technique calledbillboarding allows 2.5D games to keep onscreen sprites rotated toward the player view at all times. Some 2.5D games, such as 1993'sDoom, allow the same entity to be represented by different sprites depending on its rotation relative to the viewer, furthering the illusion of 3D.
Fully 3D games usually present world objects as3D models, but sprites are supported in some 3Dgame engines, such asGoldSrc[18] andUnreal,[19] and may be billboarded or locked to fixed orientations. Sprites remain useful for small details,particle effects, and other applications where the lack of a third dimension is not a major detriment.
These are base hardware specs and do not include additional programming techniques, such as usingraster 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 | Ref. |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Amstrad Plus | ASIC | 1990 | 16 | 16 | ? | 16 | 16 | 15 | 2, 4× vertical, 2, 4× horizontal | No | No | Color key | [20] |
Atari 2600 | TIA | 1977 | 5 | 5 | 19 | 1, 8 | 262 | 1 | 2, 4, 8× horizontal | Horizontal mirroring | Yes | Color key | [21] |
Atari 8-bit computers | GTIA/ANTIC | 1979 | 8 | 8 | 40 | 2, 8 | 128, 256 | 1 | 2× vertical, 2, 4× horizontal | No | Yes | Color key | [22] |
Commodore 64 | VIC-II | 1982 | 8 | 8 | 96, 192 | 12, 24 | 21 | 1, 3 | 2× integer | No | Yes | Color key | [23] |
Amiga (OCS) | Denise | 1985 | 8, can be reused horizontally per 4 pixel increments | Arbitrary, 8 unique | Arbitrary | 16 | Arbitrary | 3, 15 | Vertical by display list | No | Yes | Color key | [24] |
Amiga (AGA) | Lisa | 1992 | 8, can be reused horizontally per 2 pixel increments | Arbitrary, 8 unique | Arbitrary | 16, 32, 64 | Arbitrary | 3, 15 | Vertical by display list | No | Yes | Color key | |
ColecoVision | TMS9918A | 1983 | 32 | 4 | 64 | 8, 16 | 8, 16 | 1 | 2× integer | No | Partial | Color key | |
TI-99/4 & 4A | TMS9918 | 1979 | 32 | 4 | 64 | 8, 16 | 8, 16 | 1 | 2× integer | No | Partial | Color key | |
Gameduino | 2011 | 256 | 96 | 1,536 | 16 | 16 | 255 | No | Yes | Yes | Color key | [25] | |
Intellivision | STIC AY-3-8900 | 1979 | 8 | 8 | 64 | 8 | 8,16 | 1 | 2, 4, 8× vertical, 2× horizontal | Horizontal and vertical mirroring | Yes | Color key | [26] |
MSX | TMS9918A | 1983 | 32 | 4 | 64 | 8, 16 | 8, 16 | 1 | 2× integer | No | Partial | Color key | [27] |
MSX2 | Yamaha V9938 | 1986 | 32 | 8 | 128 | 8, 16 | 8,16 | 1, 3, 7, 15 per line | 2× integer | No | Partial | Color key | |
MSX2+ /MSX turbo R | Yamaha V9958 | 1988 | 32 | 8 | 128 | 8,16 | 8,16 | 1, 3, 7, 15 per line | 2× integer | No | Partial | Color key | |
Namco Pac-Man (arcade) | TTL | 1980 | 6 | 6 | 96 | 16 | 16 | 3 | No | Horizontal and vertical mirroring | No | Color key | [28] |
TurboGrafx-16 | HuC6270A | 1987 | 64 | 16 | 256 | 16, 32 | 16, 32, 64 | 15 | No | Horizontal and vertical mirroring | Yes | Color key | [29] |
Namco Galaxian (arcade) | TTL | 1979 | 7 | 7 | 112 | 16 | 16 | 3 | No | Horizontal and vertical mirroring | No | Color key | [30][31][32] |
NintendoDonkey Kong,Radar Scope (arcade) | 1979 | 128 | 16 | 256 | 16 | 16 | 3 | Integer | No | Yes | Color key | [33] | |
Nintendo DS | Integrated PPU | 2004 | 128 | 128 | 1,210 | 8, 16, 32, 64 | 8, 16, 32, 64 | 65,536 | Affine | Affine | No | Color key, blending | [34] |
NES/Famicom | RicohRP2C0x PPU | 1983 | 64 | 8 | 64 | 8 | 8, 16 | 3 | No | Horizontal and vertical mirroring | Partial | Color key | [35] |
Game Boy | Integrated PPU | 1989 | 40 | 10 | 80 | 8 | 8, 16 | 3 | No | Horizontal and vertical mirroring | No | Color key | [36] |
Game Boy Advance | Integrated PPU | 2001 | 128 | 128 | 1210 | 8, 16, 32, 64 | 8, 16, 32, 64 | 15, 255 | Affine | Affine | No | Color key, blending | [37] |
Master System, Game Gear | YM2602B VDP (TMS9918-derived) | 1985 | 64 | 8 | 128 | 8, 16 | 8, 16 | 15 | 2× integer, 2× vertical | Background tile mirroring | Yes | Color key | [38][39] |
Genesis / Mega Drive | YM7101 VDP (SMS VDP-derived) | 1988 | 80 | 20 | 320 | 8, 16, 24, 32 | 8, 16, 24, 32 | 15 | No | Horizontal and vertical mirroring | Yes | Color key | [40][41] |
Sega OutRun (arcade) | 1986 | 128 | 128 | 1600 | 8 to 512 | 8 to 256 | 15 | Anisotropic | Horizontal and vertical mirroring | Yes | Alpha | [42][43][44][45][46][47][48] | |
X68000 | Cynthia jr. (original), Cynthia (later models) | 1987 | 128 | 32 | 512 | 16 | 16 | 15 | 2× integer | Horizontal and vertical mirroring | Partial | Color key | [49][50][51] |
Neo Geo | LSPC2-A2 | 1990 | 384 | 96 | 1536 | 16 | 16 to 512 | 15 | Sprite shrinking | Horizontal and vertical mirroring | Partial | Color key | [52][53][54] |
Super NES / Super Famicom | S-PPU1, S-PPU2 | 1990 | 128 | 34 | 256 | 8, 16, 32, 64 | 8, 16, 32, 64 | 15 | No | Horizontal and vertical mirroring | No | Color key, averaging | [55] |
System | Sprite hardware | Introduced | Sprites on screen | Sprites on line | Max.texels on line | Texture width | Texture height | Colors | Hardware zoom | Rotation | Collision detection | Transparency | Source |
[…] 6 moving characters, what you would call today "sprites" we called them "stamps" back then, […].
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