In "real-time" IF, turns advance even while the player sits and does nothing. Compared to the majority of turn-based IF, in which time passes only when the interactor types, real-time IF are rare and unconventional.
Common Uses of Real-Time in IF
The uses of real-time elements in IF are quite varied, and may include:
- amplifying a sense of risk
- creating ambiance
- enabling animation
- supporting multiplayer interaction
Some games use a real-time clock throughout, others go into a real-time mode only during a crucial scene. Still others make real-time interaction an optional real-time mode which may be turned on or off, such as The Battle of Walcot Keep. Most use real-time to advance the IF without user input, but a few also use it to enable pseudo-graphical animated displays such as the fence scenes in Border Zone. The real-time abilities of specifications such as Z-code version 5 have been used by contemporary IF authors to create non-IF "abuses," for example Freefall, an arcade game port of Tetris.
Real-time elements may involve any speed of time passage, so long as it passes without input. For example, Demoniak advances time one turn only after ~40 seconds of inactivity, while Madness and the Minotaur may kill the inactive player within the first 15 seconds of play.
MUD-based IF can easily allow multiple players to interact with the same IF work due to the default support of MUDs for real-time interaction. The MUD can serve as either a chatroom wrapper which interfaces with a normal turn-based IF or, alternately, an environment in which IF is modeled for multiplayer real-time interaction. In addition to instantaneous actions and timed events, may MUDs also support a turn period or 'heartbeat' which advances every x seconds.
Hybrid command line / graphic adventure games such as the early King's Quest and Hero's Quest games by Sierra also sometimes involved typing commands in order to intervene in real-time processes.
Common Problems with Real-Time IF
Real-time IF disrupts the convention of IF interaction as contemplative reading, often with the goal of creating a sense of increased ambience or of urgent pacing. This introduces new challenges for the player, particularly with typos and disambiguation. The player is rushed, and thus much more likely to make errors while typing quickly. At the same time, the player must be even more careful to avoid typos than in turn-based IF, as real-time IF continues to advance whether a command is understood or not.
A related technical problem is that it is often difficult for real-time IF systems to support the UNDO command. Lack of undo further heightens both the risks of real-time interaction and the frustration when interaction fails due to typos.
Developing Real-Time IF
Contemporary development systems such as Inform 7 and TADS 3 all support real-time, although by default they create turn-based works. TADS 3 in particular has extensive built-in (but optional) support for real-time.
History of Real-Time IF
Examples of real-time IF go back at least as far as 1981 with Madness and the Minotaur, perhaps further. Real-time IF were the standard house-style of certain 1980s commercial IF publishers, including Melbourne House and Synapse Software. Other major publishers experimented with real-time only occasionally, e.g. Infocom and its 1987 release of Border Zone. While real-time IF have always been the exception, they have grown even more rare in recent years.
Examples of IF Using Real-Time
- And the Waves Choke the Wind (Gunther Schmidl; 2000).
- Border Zone (Marc Blank; publisher: Infocom; 1987).
- Brainscape (Lynne Ostergren and W. Jeffrey Wilson; 1985).
- Breakers (author: Rod Smith, programmers: Joe Vierra and William Mataga; publisher: Synapse Software; 1986).
- Brimstone: The Dream of Gawain (author: James Paul, programmers: David Bunch, William Mataga, Bill Darrah; publisher: Synapse Software; 1985).
- Demoniak (Publisher: Palace Software; 1990).
- Drool (Jeff Breidenbach; 1994).
- Dungeons of Daggorath (Douglas Morgan; 1982).
- Essex (author: Bill Darrah, programmers: Bill Darrah and William Mataga; publisher: Synapse Software; 1985).
- Eureka! (Ian Livingstone; publisher: Domark; 1984).
- Getting Back to Sleep (Patrick Evans; 2004).
- Hex (Geoff Larsen; publisher: Larsoft).
- The Hobbit (Philip Mitchell and Veronika Megler; publisher: Melbourne House; 1982).
- Lord of the Rings 3: Crack of Doom (Publisher: Melbourne House; 1989).
- Madness and the Minotaur (Spectral Associates; 1981).
- Mindwheel (author: Robert Pinsky, programmers: Steve Hales and William Mataga; publisher: Synapse Software; 1984).
- Mr. Remote Mom (Lenny Pitts; 2000).
- Rat In Control (Michael J. Roberts; 2003; TADS 3).
- Sadim Castle (MP Software for the Acorn Electron; 1984).
- Shadows of Mordor (Philip Mitchell; publisher: Melbourne House; 1987)
- Sherlock (by Mitchell) (Philip Mitchell; publisher: Melbourne House; 1985)
- Sylenius Mysterium (C.E. Forman; 1997).
- Time and Dwarves (Graham Nelson; Inform demo; 1997).