Random and Raster: Display Technologies and the Development of Videogames The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. Citation Montfort, N., and I. Bogost. “Random and Raster: Display Technologies and the Development of Videogames.” Annals of the History of Computing, IEEE 31.3 (2009): 34-43. © 2009 IEEE. As Published http://dx.doi.org/10.1109/MAHC.2009.50 Publisher Institute of Electrical and Electronics Engineers Version Final published version Citable link http://hdl.handle.net/1721.1/60006 Terms of Use Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. Random and Raster: Display Technologies and the Development of Videogames Nick Montfort Massachusetts Institute of Technology Ian Bogost Georgia Institute of Technology Videogame developers have utilized many types of display technology, from oscilloscopes to Teletypes to high-definition LCD displays. Two significant early display technologies, raster scan and random scan CRTs, played a significant part in the history and evolution of videogames. A study of these technologies shows how the choice of one or the other, and the need to port games between the two, influenced game design and prompted developers to innovate. Many forces have shaped the development of programmer writing a game for a PDP-1 videogame displays and influenced the design would have assumed that a text-output video and functionality of games, not just their terminal or Teletype machine would be ready appearance. The videogame display technolo- at hand, and a coin-operated (coin-op) arcade gies that were put to use, and the extent game creator might have some flexibility in to which they were used, had a great deal to choosing a particular type or orientation of do with convenience and the ability to source monitor in the cabinet. No matter the type, dis- display components. Since early videogame play technologies have exerted a strong influ- implementations, resolutions have increased, ence on the evolution of videogames. bulky video picture tubes have given way From the end of the 1970s through the to widescreen flat-panel LCD displays, and 1980s, two fundamentally different display increased computing power has allowed technologies were in use side by side in real-time 3D graphics to replace 80-column arcades. The raster-scan display, which worked text displays. Conventional wisdom might as- similarly to the pre-flat-screen TV (an electron sume that such changes amount to simple beam swept across and down the screen to technological improvements. draw the image), was used in Space Invaders, Looking back over the history of gaming, Berzerk, Pac-Man, Donkey Kong, Robotron: 2084, however, reveals that different display technol- and many other coin-ops. Other systems used ogies have exerted creative force on the devel- random-scan displays (also called vector graph- opment of specific videogames. During the ics, stroke writing, and calligraphic), which ar- last half-century, very different display tech- bitrarily pointed an electron gun. Atari used nologies have provided the ‘‘video’’ in video- this technology, calling it XY graphics, when games. For example, the very early game it developed Tempest, Battlezone, Asteroids,and Tennis for Two used an oscilloscope, and early Lunar Lander. (See the sidebar for more details text adventures played on minicomputers about specific games.) often used a Teletype or other print terminal In this article, we describe some of the in- to print output on paper. Sometimes the dis- teraction between early videogame develop- play technology was imposed by the game ment and display technologies, considering play. For example, videogames played in the the influence of XY graphics in contrast to home typically can’t rely on expensive or un- the more familiar raster-scan system. In the usual displays, so an ordinary television is usu- 1970s, both random and raster displays ally the most sensible display choice. But a were commonly used in many applications, 34 IEEE Annals of the History of Computing Published by the IEEE Computer Society 1058-6180/09/$26.00 c 2009 IEEE Further Reading on Videogame History We have not individually cited each well-known and References well-documented historical fact (such as the release years of popular videogames) because such detail is outside the 1. V. Burnham, Supercade: A Visual History of the scope of this article. For general information on videogame Videogame Age 19711984, MIT Press, 2003. history, we suggest several books.15 There are also helpful 2. R. DeMaria and J. Wilson, High Score!: The resources easily found online, such as the longstanding Illustrated History of Electronic Games, Osborne/ Killer List of Videogames (http://www.klov.com) and the McGraw-Hill, 2002. project MobyGames (http://www.mobygames.com). 3. W. Forster, The Encyclopedia of Game Machines, Information about the basic functioning of games can be Gameplan, 2005. easily determined by playing the games themselves. 4. S.L. Kent, The Ultimate History of Video Games, Although certain information on the history of video- Prima, 2001. games, both online and in print, might be less than reli- 5. B. Weiss, Classic Home Video Games, 19721984, able, basic information about which companies and programmers developed popular games is not usually McFarland, 2007. in dispute. and XY graphics systems presented them- The electron beam does not sweep across the selves as viable candidates for adoption in screen from left to right, being turned on coin-op games like Asteroids and Star Castle. and off as it makes its way down and then Often, random-scan types of displays offered returns back to the top 60 times each second. a kind of high-resolution graphics unavail- Instead, the electron gun is pointed at a cer- able in raster displays—for example, by tain location, turned on, and moved from smoothly scaling and rotating graphics in a that (x, y) coordinate to another point in a way that would otherwise have been diffi- straight line, where it is turned off again. An cult, if not impossible. oscilloscope functions similarly; it just deflects Gaming brought both displays to a broad the electron beam using electrostatic force. XY public and into contact with one another, monitors use magnetic force. along with new constraints. Differences be- Just as a storage device that is arbitrarily ac- tween the two systems meant that developers cessible offers random access, random scan porting popular random-scan coin-op titles uses a beam that can be made to move any- were forced to deliberately evaluate game ele- where. Such systems directly draw lines in ments, sometimes devising entirely new an (x, y) coordinate system. Raster-graphics approaches to similar high-level game con- systems, on the other hand, draw a grid of cepts. When games that originally used vec- data representing a pattern of pixels. If the tor displays were ported to raster-based correspondence between bits and pixels is home systems, the practical differences be- one to one, the data is a bitmap; more gener- tween the display technologies were revealed ally, such data is a pixmap (p. 13).1 As a result, in a particularly interesting way—for exam- it is possible to render detailed bitmapped ple, this is the case with the home version images on a raster system, but a vector system of Asteroids, developed for the Atari VCS makes it much easier to scale, shear, and ro- (a.k.a. Atari 2600), and the Atari VCS game tate shapes that have been drawn with the Yars’ Revenge, which was inspired by Star Cas- primitives of that system. tle. By looking at Yars’ Revenge and Asteroids In the 1980s, other differences between in detail, we can see how developers modi- the two types of displays included the acces- fied the games to account for the different sibility of color and black-and-white raster display systems. Similarly, the home and ar- displays, the better brightness and resolution cade versions of Battlezone and Tempest of vector displays, and the limited number of show how entirely new ways of depicting primitives that could be drawn on a vector the world on screen came about. display before it began to flicker. Videogame systems were not the first to explore the uses Random and raster display of either type of display. Both had been technologies employed in computer graphics for a while Although all early arcade games used CRTs, before commercial videogaming came about, those in vector-graphics games are wired and by the mid-1970s, raster graphics had be- differently than the ones in standard TVs. come dominant (p. 12).2 July–September 2009 35 History of Computer Games The building blocks of Star Castle A hit arcade game would have already had a Programmer Howard Scott Warshaw’s first following, one that might have generated en- assignment at Atari was to port the 1980 thusiasm and an initial market. Even in the vector-graphics arcade game Star Castle, pro- early days of videogaming, when the arcade duced by Cinematronics, to the Atari VCS. hits were Pong and Tank rather than Pac- He told an interviewer, ‘‘I soon realized that Man, an arcade game’s fan following was im- a decent version couldn’t be done, so I took portant when it came to the home console what I thought were the top logical and geo- market. Given the differences in platform metric components of Star Castle and reor- and the need to rewrite each game from ganized them in a way that would better scratch, a port to the Atari VCS had plenty suit the machine.’’3 of room to become a fairly involved adapta- Warshaw’s comment reveals how the plat- tion rather than a straightforward re-creation.