Interactive fiction (IF) issoftware simulating environments in which players use textcommands to controlcharacters and influence the environment. Works in this form can be understood asliterarynarratives, either in the form ofInteractive narratives orInteractive narrations. These works can also be understood as a form ofvideo game,[1] either in the form of anadventure game orrole-playing game. In common usage, the term refers totext adventures, a type ofadventure game where the entire interface can be "text-only",[2] however, graphical text adventure games, where the text is accompanied by graphics (still images, animations or video) still fall under the text adventure category if the main way to interact with the game is by typing text. Some users of the term distinguish between interactive fiction, known as "Puzzle-free", that focuses on narrative, and "text adventures" that focus onpuzzles.
Due to their text-only nature, they sidestepped the problem of writing for widely divergent graphics architectures. This feature meant that interactive fiction games were easily ported across all the popular platforms at the time, includingCP/M (not known for gaming or strong graphics capabilities). The number of interactive fiction works is increasing steadily as new ones are produced by an online community, using freely available development systems[citation needed].
The term can also be used to refer to literary works that are not read in a linear fashion, known asgamebooks, where the reader is instead given choices at different points in the text; these decisions determine the flow and outcome of the story. The most famous example of this form of printed fiction is theChoose Your Own Adventure book series, and the collaborative "addventure" format has also been described as a form of interactive fiction.[3] The term "interactive fiction" is sometimes used also to refer tovisual novels, a type ofinteractive narrative software popular in Japan.
Text adventures are one of the oldest types ofcomputer games and form a subset of theadventure genre. The player uses text input to control the game, and the game state is relayed to the player via text output. Interactive fiction usually relies onreading from a screen and ontyping input, although text-to-speech synthesizers allow blind and visually impaired users to play interactive fiction titles asaudio games.[2]
Input is usually provided by the player in the form of simplesentences such as "get key" or "go east", which are interpreted by atext parser. Parsers may vary in sophistication; the first text adventure parsers could only handle two-word sentences in the form of verb-noun pairs. Later parsers, such as those built on ZIL (Zork Implementation Language), could understand complete sentences.[4] Later parsers could handle increasing levels of complexity parsing sentences such as "open the red box with the green key then go north". This level of complexity is the standard for works of interactive fiction today.
Despite their lack of graphics, text adventures include a physical dimension where players move between rooms. Many text adventure games boasted their total number of rooms to indicate how much gameplay they offered.[2] These games are unique in that they may create anillogical space, where going north from area A takes you to area B, but going south from area B did not take you back to area A. This can create mazes that do not behave as players expect, and thus players must maintain their own map. These illogical spaces are much more rare in today's era of3D gaming,[2] and the Interactive Fiction community in general decries the use of mazes entirely, claiming that mazes have become arbitrary 'puzzles for the sake of puzzles' and that they can, in the hands of inexperienced designers, become immensely frustrating for players to navigate.
Interactive fiction shares much in common withMulti-User Dungeons ('MUDs'). MUDs, which became popular in the mid-1980s, rely on a textual exchange and accept similar commands from players as do works of IF; however, since interactive fiction is single player, and MUDs, by definition, have multiple players, they differ enormously in gameplay styles. MUDs often focus gameplay on activities that involve communities of players, simulated political systems, in-game trading, and other gameplay mechanics that are not possible in a single player environment.
Interactive fiction features two distinct modes of writing: the player input and the game output. As described above, player input is expected to be in simple command form (imperative sentences).[5] A typical command may be:
> PULL Lever
The responses from the game are usually written from asecond-personpoint of view, inpresent tense. This is because, unlike in most works of fiction, the main character is closely associated with the player, and the events are seen to be happening as the player plays. While older text adventures often identified the protagonist with the player directly, newer games tend to have specific, well-defined protagonists with separate identities from the player. The classic essay "Crimes Against Mimesis"[6] discusses, among other IF issues, the nature of "You" in interactive fiction. A typical response might look something like this, the response to "look in tea chest" at the start ofCurses:
"That was the first place you tried, hours and hours ago now, and there's nothing there but that boring old book. You pick it up anyway, bored as you are."[7]
Many text adventures, particularly those designed for humour (such asZork,The Hitchhiker's Guide to the Galaxy, andLeather Goddesses of Phobos), address the player with an informal tone, sometimes including sarcastic remarks (see the transcript fromCurses, above, for an example). The late Douglas Adams, in designing the IF version of his 'Hitchhiker's Guide to the Galaxy', created a unique solution to the final puzzle of the game: the game requires the one solitary item that the playerdidn't choose at the outset of play.
Some IF works dispense with second-person narrative entirely, opting for a first-person perspective ('I') or even placing the player in the position of an observer, rather than a direct participant. In some 'experimental' IF, the concept of self-identification is eliminated, and the player instead takes the role of an inanimate object, a force of nature, or an abstract concept; experimental IF usually pushes the limits of the concept and challenges many assumptions about the medium.
Though neither program was developed as a narrative work, the software programsELIZA (1964–1966) andSHRDLU (1968–1970) can formally be considered early examples of interactive fiction, as both programs usednatural language processing to take input from their user and respond in a virtual and conversational manner. ELIZA simulated a psychotherapist that appeared to provide human-like responses to the user's input, while SHRDLU employed an artificial intelligence that could move virtual objects around an environment and respond to questions asked about the environment's shape. The development of effective natural language processing would become an essential part of interactive fiction development.[8]
Around 1975,Will Crowther, a programmer and an amateur caver, wrote the first text adventure game,Adventure (originally calledADVENT because a filename could only be six characters long in theoperating system he was using, and later namedColossal Cave Adventure).[9] Having just gone through a divorce, he was looking for a way to connect with his two young children. Over the course of a few weekends, he wrote a text based cave exploration game that featured a sort of guide/narrator who spoke in full sentences and who understood simple two word commands that came close to natural English. Adventure was programmed inFortran for thePDP-10. Crowther's original version was an accuratesimulation of part of the real lifeMammoth Cave, but also included fantasy elements (such as axe-wielding dwarves and a magic bridge).
Stanford University graduate studentDon Woods discoveredAdventure while working at theStanford Artificial Intelligence Laboratory, and in 1977 obtained and expanded Crowther's source code (with Crowther's permission). Woods's changes were reminiscent of the writings ofJ. R. R. Tolkien, and included a troll, elves, and a volcano, which some claim is based onMount Doom, but Woods says was not.[10][11]
In early 1977, Adventure spread acrossARPAnet, and has survived on theInternet to this day. The game has since been ported to many otheroperating systems, and was included with the floppy-disk distribution of Microsoft'sMS-DOS 1.0 OS.Adventure is a cornerstone of the online IF community;[citation needed] there currently exist dozens of different independently programmed versions, with additional elements, such as new rooms or puzzles, and various scoring systems.
The popularity ofAdventure led to the wide success of interactive fiction during the late 1970s, when home computers had little, if any, graphics capability. Many elements of the original game have survived into the present, such as the command 'xyzzy', which is now included as anEaster Egg in modern games, such asMicrosoft Minesweeper.
Adventure was also directly responsible for the founding of Sierra Online (laterSierra Entertainment);Ken andRoberta Williams played the game and decided to design one of their own,[9] but with graphics.
Adventure International was founded byScott Adams (not to be confused with the creator ofDilbert). In 1978, Adams wroteAdventureland, which was loosely patterned after the (original)Colossal Cave Adventure. He took out a small ad in a computer magazine in order to promote and sellAdventureland, thus creating the first commercial adventure game. In 1979 he founded Adventure International, the first commercial publisher of interactive fiction. That same year,Dog Star Adventure was published insource code form inSoftSide, spawning legions of similar games inBASIC.
The largest company producing works of interactive fiction wasInfocom,[12] which created theZork series and many other titles, among themTrinity,The Hitchhiker's Guide to the Galaxy andA Mind Forever Voyaging.
In June 1977,Marc Blank, Bruce K. Daniels,Tim Anderson, andDave Lebling began writing the mainframe version ofZork (also known asDungeon), at theMIT Laboratory for Computer Science. The game was programmed in a computer language calledMDL, a variant ofLISP.
The term Implementer was the self-given name of the creators of the text adventure series Zork. It is for this reason that game designers and programmers can be referred to as animplementer, often shortened to "Imp", rather than a writer.
In early 1979, the game was completed. Ten members of theMIT Dynamics Modelling Group went on to joinInfocom when it was incorporated later that year.
In order to make its games as portable as possible, Infocom developed theZ-machine, a customvirtual machine that could be implemented on a large number of platforms, and took standardized "story files" as input.
In a non-technical sense, Infocom was responsible for developing the interactive style that would be emulated by many later interpreters. The Infocomparser was widely regarded as the best of its era. It accepted complex, complete sentence commands like "put the blue book on the writing desk" at a time when most of its competitors parsers were restricted to simple two word verb-noun combinations such as "put book". The parser was actively upgraded with new features like undo and error correction, and later games would 'understand' multiple sentence input: 'pick up the gem and put it in my bag. take the newspaper clipping out of my bag then burn it with the book of matches'.
Several companies offered optional commercialfeelies (physical props associated with a game). The tradition of 'feelies' (and the term itself) is believed to have originated withDeadline (1982), the third Infocom title afterZork I andII.[13][14] When writing this game, it was not possible to include all of the information in the limited (80KB) disk space, so Infocom created the first feelies for this game; extra items that gave more information than could be included within the digital game itself. These included police interviews, the coroner's findings, letters, crime scene evidence and photos of the murder scene.
These materials were very difficult for others to copy or otherwise reproduce, and many included information that was essential to completing the game. Seeing the potential benefits of both aiding game-play immersion and providing a measure of creative copy-protection, in addition to acting as a deterrent to software piracy, Infocom and later other companies began creating feelies for numerous titles. In 1987, Infocom released a special version of the first threeZork titles together with plot-specific coins and other trinkets.[15][16] This concept would be expanded as time went on, such that later game feelies would contain passwords, coded instructions, page numbers, or other information that would be required to successfully complete the game.
Interactive fiction became a standard product for many software companies. By 1982Softline wrote that "the demands of the market are weighted heavily toward hi-res graphics" in games like Sierra'sThe Wizard and the Princess and its imitators. Suchgraphic adventures became the dominant form of the genre on computers with graphics, like the Apple II.[17] By 1982Adventure International began releasing versions of its games with graphics.[17] The company went bankrupt in 1985.Synapse Software andAcornsoft were also closed in 1985, leaving Infocom as the leading company producing text-only adventure games on the Apple II with sophisticated parsers and writing, and still advertising its lack of graphics as a virtue.[17] The company was bought byActivision in 1986 after the failure ofCornerstone, Infocom's database software program, and stopped producing text adventures a few years later. Soon after, Telaium/Trillium also closed.
Probably the first commercial work of interactive fiction produced outside the U.S. was thedungeon crawl game ofAcheton, produced in Cambridge, England, and first commercially released byAcornsoft (later expanded and reissued byTopologika). Other leading companies in theUK wereMagnetic Scrolls andLevel 9 Computing. Also worthy of mention areDelta 4,Melbourne House, and thehomebrew companyZenobi.
In the early 1980sEdu-Ware also produced interactive fiction for theApple II as designated by the "if" graphic that was displayed on startup. Their titles included thePrisoner andEmpire series (Empire I: World Builders,Empire II: Interstellar Sharks,Empire III: Armageddon).
In 1981,CE Software publishedSwordThrust as a commercial successor to theEamon gaming system for the Apple II. SwordThrust and Eamon were simple two-word parser games with manyrole-playing elements not available in other interactive fiction.[18] While SwordThrust published seven different titles, it was vastly overshadowed by the non-commercial Eamon system which allowed private authors to publish their own titles in the series. By March 1984, there were 48 titles published for the Eamon system (and over270 titles in total as of March 2013).
In Italy, interactive fiction games were mainly published and distributed through various magazines in included tapes. The largest number of games were published in the two magazines Viking and Explorer,[19] with versions for the main 8-bit home computers (ZX Spectrum,Commodore 64, andMSX). The software house producing those games was Brainstorm Enterprise, and the most prolific IF author wasBonaventura Di Bello,[20] who produced 70 games in the Italian language. The wave of interactive fiction in Italy lasted for a couple of years thanks to the various magazines promoting the genre, then faded and remains still today a topic of interest for a small group of fans and less known developers, celebrated on Web sites and in related newsgroups.
In Spain, interactive fiction was considered a minority genre, and was not very successful. The first Spanish interactive fiction commercially released wasYenght in 1983, byDinamic Software, for the ZX Spectrum. Later on, in 1987, the same company produced an interactive fiction aboutDon Quijote. After several other attempts, the companyAventuras AD, emerged from Dinamic, became the main interactive fiction publisher in Spain, including titles like a Spanish adaptation ofColossal Cave Adventure, an adaptation of the Spanish comicEl Jabato, and mainly theCi-U-Than trilogy, composed byLa diosa de Cozumel (1990),Los templos sagrados (1991) andChichen Itzá (1992). During this period, the Club de Aventuras AD (CAAD), the main Spanish speaking community around interactive fiction in the world, was founded, and after the end of Aventuras AD in 1992, the CAAD continued on its own, first with their own magazine, and then with the advent of Internet, with the launch of an active internet community that still produces interactive non commercial fiction nowadays.[21]
Legend Entertainment was founded byBob Bates andMike Verdu in 1989. It started out from the ashes of Infocom. The text adventures produced by Legend Entertainment used (high-resolution) graphics as well as sound. Some of their titles includeEric the Unready, theSpellcasting series andGateway (based onFrederik Pohl's novels).
The last text adventure created by Legend Entertainment wasGateway II (1992), while the last game ever created by Legend wasUnreal II: The Awakening (2003) – the well-knownfirst-person shooter action game using theUnreal Engine for both impressive graphics and realistic physics. In 2004, Legend Entertainment was acquired byAtari, who publishedUnreal II and released for both Microsoft Windows and Microsoft's Xbox.
Many other companies such as Level 9 Computing, Magnetic Scrolls, Delta 4 and Zenobi had closed by 1992.
In 1991 and 1992,Activision releasedThe Lost Treasures of Infocom in two volumes, a collection containing most of Infocom's games, followed in 1996 byClassic Text Adventure Masterpieces of Infocom.
After the decline of the commercial interactive fiction market in the 1990s, an online community eventually formed around the medium. In 1987, theUsenet newsgrouprec.arts.int-fiction was created, and was soon followed byrec.games.int-fiction. By custom, the topic ofrec.arts.int-fiction is interactive fiction authorship and programming, whilerec.games.int-fiction encompasses topics related to playing interactive fiction games, such as hint requests and game reviews. As of late 2011, discussions between writers have mostly moved fromrec.arts.int-fiction to the Interactive Fiction Community Forum.[22]
One of the most important early developments was the reverse-engineering of Infocom'sZ-Code format andZ-Machinevirtual machine in 1987 by a group of enthusiasts called theInfoTaskForce and the subsequent development of aninterpreter for Z-Code story files. As a result, it became possible to play Infocom's work on modern computers.
For years, amateurs with the IF community produced interactive fiction works of relatively limited scope using theAdventure Game Toolkit and similar tools.
The breakthrough that allowed the interactive fiction community to truly prosper, however, was the creation and distribution of two sophisticated development systems. In 1987, Michael J. Roberts releasedTADS, a programming language designed to produce works of interactive fiction. In 1993,Graham Nelson releasedInform, aprogramming language and set of libraries whichcompiled to a Z-Code story file. Each of these systems allowed anyone with sufficient time and dedication to create a game, and caused a growth boom in the online interactive fiction community.
Despite the lack of commercial support, the availability of high quality tools allowed enthusiasts of the genre to develop new high quality games. Competitions such as the annualInteractive Fiction Competition for short works, theSpring Thing for longer works, and theXYZZY Awards, further helped to improve the quality and complexity of the games. Modern games go much further than the original "Adventure" style, improving upon Infocom games, which relied extensively on puzzle solving, and to a lesser extent on communication with non player characters, to include experimentation with writing and story-telling techniques.
While the majority of modern interactive fiction that is developed is distributed for free, there are some commercial endeavors. In 1998,Michael Berlyn, a former Implementor at Infocom, started a new game company, Cascade Mountain Publishing, whose goals were to publish interactive fiction. Despite the Interactive Fiction community providing social and financial backing, Cascade Mountain Publishing went out of business in 2000. Buster Hudson, developer ofThe Wizard Sniffer (2017), emphasized that parser-based puzzle can be used to control the pacing or develop a character.[23]
Other commercial endeavors include: Peter Nepstad's1893: A World's Fair Mystery, several games by Howard Sherman published asMalinche Entertainment, The General Coffee Company'sFuture Boy!,Cypher, a graphically enhanced cyberpunk game and various titles byTextfyre.[24]Emily Short was commissioned to develop the gameCity of Secrets but the project fell through and she ended up releasing it herself.[25]
The games that won both theInteractive Fiction Competition and theXYZZY Awards areAll Roads (2001),Slouching Towards Bedlam (2003),Vespers (2005),Lost Pig (2007),Violet (2008),Aotearoa (2010),Coloratura (2013), andThe Wizard Sniffer (2017).
The original Interactive fiction Colossal Cave Adventure was programmed inFortran, originally developed byIBM. Adventure's parsers could only handle two-word sentences in the form of verb-noun pairs.
Infocom's games of 1979–88, such asZork, were written using aLISP-like programming language called ZIL (Zork Implementation Language or Zork Interactive Language; it was referred to as both) that compiled into abyte code able to run on a standardizedvirtual machine called theZ-machine. As the games were text based and used variants of the same Z-machine interpreter, the interpreter only had to be ported to acomputer once, rather than once each game. Each game file included a sophisticatedparser which allowed the user to type complex instructions to the game. Unlike earlier works of interactive fiction which only understood commands of the form 'verb noun', Infocom's parser could understand a wider variety of sentences. For instance one might type "open the large door, then go west", or "go to the hall". With the Z-machine, Infocom was able to release most of their games for most popularhome computers of the time simultaneously, includingApple II,Atari 8-bit computers,IBM PC compatibles,Amstrad CPC/PCW (one disc worked on both machines),Commodore 64,Plus/4,Commodore 128,KayproCP/M,TI-99/4A,Macintosh,Atari ST,Amiga, andTRS-80.
During the 1990s Interactive fiction was mainly written with C-like languages, such asTADS 2 andInform 6. A number of systems for writing interactive fiction now exist. The most popular remainInform,TADS, orADRIFT, but they diverged in their approach to IF-writing during the 2000s, giving today's IF writers an objective choice. By 2006IFComp, most games were written for Inform, with a strong minority of games for TADS and ADRIFT, followed by a small number of games for other systems.[42]
While familiarity with a programming language leads many new authors to attempt to produce their own complete IF application, most established IF authors recommend use of a specialised IF language, arguing that such systems allow authors to avoid the technicalities of producing a full featured parser, while allowing broad community support. The choice ofauthoring system usually depends on the author's desired balance of ease of use versus power, and the portability of the final product.[43]
Other development systems include:
Interpreters are the software used to play the works of interactive fiction created with a development system. Since they need to interact with the player, the "story files" created by development systems are programs in their own right. Rather than running directly on any one computer, they are programs run by Interpreters, or virtual machines, which are designed specially for IF. They may be part of the development system, or can be compiled together with the work of fiction as a standaloneexecutable file.
The Z-machine was designed by the founders ofInfocom, in 1979. They were influenced by the then-new idea of avirtual Pascal computer, but replaced P with Z for Zork, the celebrated adventure game of 1977–79. The Z-machine evolved during the 1980s but over 30 years later, it remains in use essentially unchanged. Glulx was designed by Andrew Plotkin in the late 1990s as a new-generation IF virtual machine. It overcomes the technical constraint on the Z-machine by being a 32-bit rather than 16-bit processor.Frotz is a modern Z-machine interpreter originally written inC (programming language) by Stefan Jokisch in 1995 forMS-DOS. Over time it was ported to other platforms, such as Unix, RISC OS, Mac OS and most recently iOS. Modern Glulx interpreters are based on "Glulxe", by Andrew Plotkin, and "Git", by Iain Merrick. Other interpreters include Zoom for Mac OS X, or for Unix or Linux, maintained by Andrew Hunter, and Spatterlight for Mac OS X, maintained by Tor Andersson.
In addition to commercial distribution venues and individual websites, many works of free interactive fiction are distributed through community websites. These include the Interactive Fiction Database (IFDb), The Interactive Fiction Reviews Organization (IFRO), a game catalog and recommendation engine, and the Interactive Fiction Archive.
Works may be distributed for playing with in a separate interpreter. In which case they are often made available in theBlorbpackage format that many interpreters support. A filename ending .zblorb is a story file intended for a Z-machine in a Blorb wrapper, while a filename ending .gblorb is a story file intended for a Glulx in a Blorb wrapper. It is not common but IF files are sometimes also seen without a Blorb wrapping, though this usually means cover art, help files, and so forth are missing, like a book with the covers torn off. Z-machine story files usually have names ending .z5 or .z8, the number being a version number, and Glulx story files usually end .ulx.
Alternatively, works may be distributed for playing in aweb browser. For example, the 'Parchment' project is for web browser-based IF Interpreter, for both Z-machine and Glulx files.
Some software such asTwine publishes directly toHTML, the standard language used to createweb pages, reducing the requirement for an Interpreter or virtual machine.
{{cite book}}: CS1 maint: publisher location (link)Some special-purpose interactive fiction development systems were used by the ordinary home computer owner of the 1980s. An important early one was Donald Brown's 1980 freeware system Eamon, a system for creating text-based role-playing games... Eamon was used to create more than 240 games.
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