Sprite (computer graphics)

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Sprite is a computer graphics term for a two-dimensional bitmap that is integrated into a larger scene, most often in a 2D video game.

Computer graphics graphics created using computers

Computer graphics are pictures and films created using computers. Usually, the term refers to computer-generated image data created with the help of specialized graphical hardware and software. It is a vast and recently developed area of computer science. The phrase was coined in 1960, by computer graphics researchers Verne Hudson and William Fetter of Boeing. It is often abbreviated as CG, though sometimes erroneously referred to as computer-generated imagery (CGI).

Two-dimensional space Geometric model of the planar projection of the physical universe

Two-dimensional space is a geometric setting in which two values are required to determine the position of an element. In mathematics, it is commonly represented by the symbol 2. For a generalization of the concept, see dimension.

In computing, a bitmap is a mapping from some domain to bits. It is also called a bit array or bitmap index.

Contents

Originally sprites referred to independent objects that are composited together, by hardware, with other elements such as a background. [1] The composition occurs as each scan line is prepared for the video output device, such as a CRT, without involvement of the main CPU and without the need for a full-screen frame buffer. [1] Sprites can be positioned or altered by setting attributes used during the hardware composition process. Examples of systems with hardware sprites include the Texas Instruments TI-99/4A, Atari 8-bit family, Commodore 64, Amiga, Nintendo Entertainment System, Sega Genesis, and many coin-operated arcade machines of the 1980s. Sprite hardware varies in how many sprites are supported, how many can be displayed on a single scan line (which is often a lower number), the dimensions and colors of each sprite, and special effects such as scaling or reporting pixel-precise overlap.

Scan line

A scan line is one line, or row, in a raster scanning pattern, such as a line of video on a cathode ray tube (CRT) display of a television set or computer monitor.

Cathode-ray tube vacuum tube that can show moving pictures, vector graphics, or lines

The cathode-ray tube (CRT) is a vacuum tube that contains one or more electron guns and a phosphorescent screen, and is used to display images. It modulates, accelerates, and deflects electron beam(s) onto the screen to create the images. The images may represent electrical waveforms (oscilloscope), pictures, radar targets, or other phenomena. CRTs have also been used as memory devices, in which case the visible light emitted from the fluorescent material is not intended to have significant meaning to a visual observer.

Central processing unit electronic circuitry within a computer that carries out the instructions of a computer program by performing the basic arithmetic, logical, control and input/output (I/O) operations specified by the instructions

A central processing unit (CPU), also called a central processor or main processor, is the electronic circuitry within a computer that carries out the instructions of a computer program by performing the basic arithmetic, logic, controlling, and input/output (I/O) operations specified by the instructions. The computer industry has used the term "central processing unit" at least since the early 1960s. Traditionally, the term "CPU" refers to a processor, more specifically to its processing unit and control unit (CU), distinguishing these core elements of a computer from external components such as main memory and I/O circuitry.

Use of the term sprite has expanded to refer to any two-dimensional bitmap used as part of a graphics display, even if drawn into a frame buffer (by either software or a GPU) instead of being composited on-the-fly at display time.

The act of manually creating sprites, as opposed to pre-rendering them or using digitized images, is a form of pixel art. It is sometimes referred to as spriting, especially in the hobbyist community.

Pixel art form of digital art, created through the use of raster graphics software, where images are edited on the pixel level

Pixel art is a form of digital art, created through the use of software, where images are edited on the pixel level. The aesthetic for this kind of graphics comes from 8-bit and 16-bit computers and video game consoles, in addition to other limited systems such as graphing calculators. In most pixel art, the color palette used is extremely limited in size, with some pixel art using only two colors.

History

The use of sprites originated with arcade games. The first video game to represent player characters as human player images was Taito's Basketball , which was licensed in February 1974 to Midway, releasing it as TV Basketball in North America. [2] [3]

Arcade game Coin-operated entertainment machine

An arcade game or coin-op game is a coin-operated entertainment machine typically installed in public businesses such as restaurants, bars and amusement arcades. Most arcade games are video games, pinball machines, electro-mechanical games, redemption games or merchandisers. While exact dates are debated, the golden age of arcade video games is usually defined as a period beginning sometime in the late 1970s and ending sometime in the mid-1980s. Excluding a brief resurgence in the early 1990s, the arcade industry subsequently declined in the Western hemisphere as competing home video game consoles such as the Sony PlayStation and Microsoft Xbox increased in their graphics and game-play capability and decreased in cost. The eastern hemisphere retains a strong arcade industry.

Player character fictional character in a role-playing or video game that can be played or controlled by a real-world person

A player character is a fictional character in a role-playing game or video game whose actions are directly controlled by a player of the game rather than the rules of the game. The characters that are not controlled by a player are called non-player characters (NPCs). The actions of non-player characters are typically handled by the game itself in video games, or according to rules followed by a gamemaster refereeing tabletop role-playing games. The player character functions as a fictional, alternate body for the player controlling the character.

Taito Japanese company

Taito Corporation is a Japanese company that specializes in video games, toys, arcade cabinets and game centers, based out of Shinjuku, Tokyo. The company was founded by Michael Kogan in 1953 as the Taito Trading Company, importing vodka, vending machines and jukeboxes into Japan. They would soon begin production of video games in 1972, renaming the company to simply Taito. In 2005, Taito was purchased by Square Enix, becoming a wholly-owned subsidiary, however they are treated as a separate entity from their parent company.

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.

Signetics integrated circuits manufacturer

Signetics was an American electronics manufacturer specifically established to make integrated circuits. Founded in 1961, they went on to develop a number of early microprocessors and support chips, as well as the widely used 555 timer chip. They were bought by Philips in 1975 and incorporated in Philips Semiconductors.

1292 Advanced Programmable Video System

The 1292 Advanced Programmable Video System is a home video game console released by European company Audiosonic in 1978. It is part of a group of software-compatible consoles which include the Interton VC-4000 and the Voltmace Database. The 1292 Advanced Programmable Video System included its power pack inside the console instead of an exterior power pack.

The Elektor TV Games Computer was a programmable computer system sold by Elektor in kit form from 1979. It used the Signetics 2650 CPU with the Signetics 2636 PVI for graphics and sound. These were the same chips as used in the Interton VC 4000 console family. A 2K monitor ROM written by Philips and a cassette interface were the most important differences between the TVGC and the Interton family. Many VC 4000 games were adapted versions of TV Games Computer games. It is possible to add cartridge slots to the TVGC to enable it to play console games, and the Hobby Module of the Acetronic console effectively transforms it into a basic TVGC.

The Atari VCS, released in 1977, features 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. [4] 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 feature 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 displaya 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.

The Namco Galaxian arcade system board, for the 1979 arcade game Galaxian , featured animated, multi-colored sprites. [5] It pioneered a sprite system that animated pre-loaded sprites over a scrolling background, which became the basis for Nintendo's Radar Scope and Donkey Kong arcade hardware and home consoles such as the Nintendo Entertainment System. [6] According to Steve Golson from General Computer Corporation, the term "stamp" was used instead of "sprite" at the time. [7]

The term sprite was first used in the graphic sense by one of the definers of the Texas Instruments 9918(A) video display processor (VDP). [8] The term was derived from the fact that sprites, rather than being part of the bitmap data in the framebuffer, instead "floated" around on top without affecting the data in the framebuffer below, much like a ghost or "sprite". By this time, sprites had advanced to the point where complete two-dimensional shapes could be moved around the screen horizontally and vertically with minimal software overhead.

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.

Computer systemSprite hardwareYearSprites on screenSprites on lineMax. texels on line Texture widthTexture heightColorsHardware zoom Rotation Background Collision detection Transparency Source
Amstrad Plus 19901616?1616151, 2, 4× vertical, 1, 2, 4× horizontalNo1 bitmap layerNoColor key [9]
Atari 2600 TIA 197753171, 826211, 2, 4, 8× horizontalHorizontal mirroring1 bitmap layerYesColor key [10]
Atari 8-bit family GTIA/ANTIC 197988402, 8128, 2561,31, 2× vertical, 1, 2, 4× horizontalNo1 tile or bitmap layerYesColor key [11]
Commodore 64 VIC-II 19828896, 19212, 24211, 31, 2× integerNo1 tile or bitmap layerYesColor key [12]
Amiga (OCS) Denise 1985Arbitrary812816Arbitrary3, 15Vertical by display listNo2 bitmap layersYes Color key [13]
Amiga (AGA) Lisa 1992Arbitrary851216, 32, 64Arbitrary3, 15Vertical by display listNo2 bitmap layersYesColor key
Colecovision Texas Instruments TMS9918 1983324648, 168, 1611, 2× integerNo1 tile layerPartialColor key
Texas Instruments TI-99/4A Texas Instruments TMS9918 1981324648, 168, 1611, 2× integerNo1 tile layerPartialColor key
Gameduino 2011256961,5361616255NoYes1 tile layerYesColor key [14]
Intellivision STIC AY-3-89001979886488,1611, 2, 4, 8× vertical, 1, 2× horizontalHorizontal and vertical mirroring1 tile layerYesColor key [15]
MSX Texas Instruments TMS9918 1983324648, 168, 1611, 2× integerNo1 tile layerPartialColor key [16]
MSX2 Yamaha V9938 19863281288, 168,161, 3, 7, 15 per line1, 2× integerNo1 tile or bitmap layerPartialColor key
MSX2+ / MSX turbo R Yamaha V9958 19883281288,168,161, 3, 7, 15 per line1, 2× integerNo1 tile or bitmap layerPartialColor key
Namco Pac-Man
(arcade)
TTL1980669616163NoHorizontal and vertical mirroring1 tile layerNoColor key [17]
TurboGrafx-16 HuC6270A1987641625616, 3216, 32, 6415NoNo1 tile layerYesColor key
Namco Galaxian
(arcade)
TTL19797711216163NoHorizontal and vertical mirroring1 tile layerNoColor key [18] [19] [20]
Nintendo Donkey Kong, Radar Scope
(arcade)
19791281625616163IntegerNo1 tile layerYesColor key [21]
Nintendo DS Integrated PPU20041281281,2108, 16, 32, 648, 16, 32, 6465,536Yes, affine Yes, affine 4 layers per screen; each layer is independentNoColor key, blending [22]
NES/Famicom Ricoh RP2C0x PPU 19836486488, 163NoHorizontal and vertical mirroring1 tile layerPartialColor key [23]
Game Boy Integrated PPU198940108088, 163NoHorizontal and vertical mirroring1 tile layerNoColor key [24]
Game Boy Advance Integrated PPU200112812812108, 16, 32, 648, 16, 32, 6415, 255Yes, affine Yes, affine 4 layers, 2 layers, and 1 affine layer, 2 affine layersNoColor key, blending [25]
Master System,
Game Gear
VDP
(TMS9918-derived)
19856481288, 168, 16151, 2× integer, 1, 2× verticalBackground tile mirroring1 tile layerYesColor key [26] [27]
Sega Genesis YM7101 VDP
(SMS VDP-derived)
198880203208, 16, 24, 328, 16, 24, 3215NoHorizontal and vertical mirroring2 tile layersYesColor key [28] [29]
Sega OutRun (arcade)198612812816008 to 5128 to 25615Yes, anisotropic Horizontal and vertical mirroring2 tile layers and 1 bitmap layerYesAlpha [30] [31] [32] [33] [34] [35] [36]
Sharp X68000 Cynthia jr. (original), Cynthia (later models)1987128325121616151, 2× integerHorizontal and vertical mirroring1-2 tile layers and 1-4 bitmap layersPartialColor key [37] [38] [39]
Neo Geo LSPC2-A219903849615361616 to 51215Sprite shrinkingHorizontal and vertical mirroring1 tile layerPartialColor key [40] [41] [42]
Super NES/
Super Famicom
S-PPU1, S-PPU21990128342728, 16, 32, 648, 16, 32, 6415Background onlyHorizontal and vertical mirroring3 tile layers or 1 affine mapped tile layerYesColor key, averaging
Computer systemSprite hardwareYearSprites on screenSprites on lineMax. texels on line Texture widthTexture heightColorsHardware zoom Rotation Background Collision detection Transparency Source

Use in 3D rendering

2D images with alpha channels constrained to face the camera may be used in 3D graphics. They are common for rendering vegetation, to approximate distant objects, or for particle effects. These are sometimes called "billboards" or "Z-sprites". If rendered on the fly to cache an approximate view of an underlying 3D model, such sprites are called impostors. [43] Modern GPU hardware can mimic sprites with two texture-mapped triangles or specific primitives such as point sprites.

Synonyms

Some hardware makers used terms other than sprite.

Player/Missile Graphics was a term used by Atari, Inc. for hardware-generated sprites in the company's early coin-op games, the Atari 2600 and 5200 consoles, and the Atari 8-bit computers. [44] The term reflected the usage for both characters ("players") and smaller associated objects ("missiles") that share the same color.

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

The developer manuals for the Nintendo Entertainment System, Super NES, and Game Boy refer to sprites as OBJs (short for "objects"), and the region of RAM used to store sprite attributes and coordinates was known as OAM (Object Attribute Memory). This also applies on the Game Boy Advance and Nintendo DS handheld systems.

See also

Related Research Articles

Atari 2600 Video game console

The Atari 2600, originally branded as the Atari Video Computer System or Atari VCS until November 1982, is a home video game console from Atari, Inc. Released on September 11, 1977, it is credited with popularizing the use of microprocessor-based hardware and games stored on ROM cartridges instead of dedicated hardware with games physically built into the unit. The 2600 was bundled with two joystick controllers, a conjoined pair of paddle controllers, and a game cartridge: initially Combat, and later Pac-Man.

Atari 7800 video game console

The Atari 7800 ProSystem, or simply the Atari 7800, is a home video game console officially released by the Atari Corporation in 1986. It is almost fully backward-compatible with the Atari 2600, the first console to have backward compatibility without the use of additional modules. It was considered affordable at a price of US$140.

Parallax scrolling is a technique in computer graphics where background images move past the camera more slowly than foreground images, creating an illusion of depth in a 2D scene and adding to the sense of immersion in the virtual experience. The technique grew out of the multiplane camera technique used in traditional animation since the 1930s. Parallax scrolling was popularized in 2D computer graphics and video games by the arcade games Moon Patrol and Jungle Hunt, both released in 1982. Some parallax scrolling had earlier been used by the 1981 arcade game Jump Bug.

A blitter is a circuit, sometimes as a coprocessor or a logic block on a microprocessor, dedicated to the rapid movement and modification of data within a computer's memory. A blitter can copy large quantities of data from one memory area to another relatively quickly, and in parallel with the CPU, while freeing up the CPU's more complex capabilities for other operations. A typical use for a blitter is the movement of a bitmap, such as windows and fonts in a graphical user interface or images and backgrounds in a 2D video game. The name comes from the bit blit operation of the 1973 Xerox Alto, which stands for bit-block transfer. A blit operation is more than a memory copy, because it can involve data that's not byte aligned, handling transparent pixels, and various ways of combining the source and destination data.

A sound chip is an integrated circuit designed to produce sound. It might do this through digital, analog or mixed-mode electronics. Sound chips normally contain things like oscillators, envelope controllers, samplers, filters and amplifiers. During the late 20th century, sound chips were widely used in arcade game system boards, video game consoles, home computers, and PC sound cards.

Graphics processing unit specialized electronic circuit; graphics accelerator

A graphics processing unit (GPU) is a specialized electronic circuit designed to rapidly manipulate and alter memory to accelerate the creation of images in a frame buffer intended for output to a display device. GPUs are used in embedded systems, mobile phones, personal computers, workstations, and game consoles. Modern GPUs are very efficient at manipulating computer graphics and image processing. Their highly parallel structure makes them more efficient than general-purpose central processing units (CPUs) for algorithms that process large blocks of data in parallel. In a personal computer, a GPU can be present on a video card or embedded on the motherboard. In certain CPUs, they are embedded on the CPU die.

1983 has seen many sequels and prequels in video games and several new titles such as Mario Bros., Pole Position II and Spy Hunter.

In the history of computer and video games, the third generation began on July 15, 1983, with the Japanese release of two systems: the Nintendo Family Computer and Sega SG-1000. This generation marked the end of the North American video game crash, and a shift in the dominance of home video games from the United States to Japan. Handheld consoles were not a major part of this generation, although the Game & Watch line from Nintendo had started in 1980 and the Milton Bradley Microvision came out in 1979.

2.5D simulation of the appearance of being three-dimensional

The two-and-a-half-dimensional perspective is either 2D graphical projections and similar techniques used to cause images or scenes to simulate the appearance of being three-dimensional (3D) when in fact they are not, or gameplay in an otherwise three-dimensional video game that is restricted to a two-dimensional plane with a limited access to the third dimension. By contrast, games using 3D computer graphics without such restrictions are said to use true 3D.

<i>Galaxian</i> 1979 video game

Galaxian is a fixed shooter arcade game developed and released by Namco in 1979. It would be licensed out to Midway Games for manufacture and distribution in North America. In the game, the player controls a starship at the bottom of the screen as it must destroy the titular Galaxian aliens. Aliens will appear in a set formation towards the top of the screen and perform a dive-bomb towards whilst firing shots, in an effort to hit the player. Bonus points are awarded for destroying aliens in groups or by taking out enemies in mid-flight.

Television Interface Adaptor computer chip used in Atari 2600 consoles

The Television Interface Adaptor (TIA) is the custom computer chip that is the heart of the Atari 2600 game console, generating the screen display, sound effects, and reading input controllers. Its design was widely affected by an attempt to reduce the amount of RAM needed to operate the display. The resulting design is notoriously difficult to program, which is an ongoing challenge for developers.

Multi Emulator Super System (MESS) is an emulator for various consoles and computer systems, based on the MAME core and now a part of MAME. MESS emulates portable and console gaming systems, computer platforms, and calculators. The project strives for accuracy and portability and therefore is not always the fastest emulator for any one particular system. Its accuracy makes it also useful for homebrew game development.

1985 saw many sequels and prequels in video games and several new titles such as Gradius, Super Mario Bros. and Duck Hunt.

Fueled by the previous year's release of the colorful and appealing Pac-Man, the audience for arcade games in 1981 became much wider. Pac-Man influenced maze games began appearing in arcades and on home systems. Nintendo broke from their mediocre early releases with Donkey Kong which defined the platform genre.

1979 has seen many sequels and prequels in video games and several new titles such as Galaxian, Warrior and Asteroids.

The Namco Galaxian was an 8-bit arcade game system board, which was first used by Namco for Galaxian in 1979; it was the first board from the company to use the Zilog Z80 microprocessor. It used specialized graphics hardware supporting RGB color, multi-colored sprites and tilemap backgrounds. Its introduction of colorful tilemap graphics distinguished it from the Taito 8080 monochrome framebuffer system of Space Invaders. Namco Galaxian also introduced a sprite line buffer system, which was adopted by later systems such as the Namco Pac-Man, Midway's Tron hardware and Sega Z80.

Video display controller type of integrated circuit

A video display controller or VDC is an integrated circuit which is the main component in a video signal generator, a device responsible for the production of a TV video signal in a computing or game system. Some VDCs also generate an audio signal, but that is not their main function.

Sprite multiplexing is a computer graphics technique where additional sprites can be drawn on the screen, beyond the nominal maximum. It is largely historical, applicable principally to older hardware, where limited resources meant only a relatively small number of sprites were supported.

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