Adventure Game Interpreter

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AGI (Adventure Game Interpreter) was the development tool used by Sierra Online to create their early adventure games.

The first King's Quest game originally used a language named Game Assembly Language, or *.gal, by its designer, Arthur Abraham. When its main designer left, Sierra was unable to complete the game, which had been intended to showcase the technology of the IBM PCjr. IBM "donated" its product, AGI, to Sierra to allow development of King's Quest to continue.

When it debuted in the mid-1980s, AGI was innovative and made impressive use of the technology available at the time. Later versions were adapted to use 16-color EGA graphics.

By the end of the 80s, however, AGI's 160×200 resolution began to show its age and could not compete with newer engines such as Lucasfilm Games' SCUMM, which featured mouse support. In 1990, Sierra abandoned AGI and started using the SCI (Sierra's Creative Interpreter) engine for their adventure games.

The AGI system was originally designed for the IBM PCjr and clones. In the 80s it was also ported to other platforms, and some games were released commercially on the Apple II, Apple IIGS, Apple Macintosh, Amiga and Atari ST. Although there is a Sega Master System version of King's Quest and an NES version of King's Quest V, it's highly unlikely that they use the AGI software system.

[edit] List of AGI games

This is a list of Sierra games made in AGI (roughly chronological order). Note that there have been fan companies and other individuals who have produced usually shareware or 'unofficial' AGI games.

King's Quest I: Quest for the Crown (1984)
King's Quest II: Romancing the Throne (1985)
The Black Cauldron (1986)
Donald Duck's Playground (1986)
King's Quest III: To Heir Is Human (1986)
Space Quest I: The Sarien Encounter (1986)
Leisure Suit Larry in the Land of the Lounge Lizards (1987)
Mixed-Up Mother Goose (1987)
Police Quest: In Pursuit of the Death Angel (1987)
Space Quest II: Vohaul's Revenge (1987)
Gold Rush! (1988)
Manhunter: New York (1988)
King's Quest IV: The Perils of Rosella (1988) *
Manhunter 2: San Francisco (1989)

* King's Quest IV was simultaneously produced and published in both the AGI and SCI formats. The main advantages of SCI are a higher resolution (320x200 rather than 160x200 in AGI), sound card support, mouse support, and a more versatile scripting system. Sierra supposed that contemporary low-end systems would be unable to run the SCI version, thus requiring a 'lighter' version of the game. However, sales figures proved them wrong, and the AGI version was quickly discontinued. Because of its rarity, the AGI version could be considered a collector's item.

[edit] Related software

Sarien (Sierra AGI Resource Interpreter Engine) is an open source game engine recreation that can run AGI games. Sarien works on Linux/Unix, Microsoft Windows, Sega Dreamcast, and GP32. It has merged with ScummVM, now being one of the several engines supported by it.

NAGI is an open source AGI game engine recreation for Linux and Windows that is mostly complete and has additional features such as mouse support.

MEKA was the first AGI game engine recreation available to the public. The name is an acronym combining the last names of the authors (Joakim Möller, Lance Ewing, and Peter Kelly), and the word Adventure. It is open source and is only available for DOS.

DAGII is an AGI game engine recreation by David Symonds. It can only play games that are built into its database, and the compatibility isn't high. It is still under development, and runs well under Linux/Unix and Mac OS X.

JAGI is an open source AGI game engine recreation by Jens Christian for Linux. It isn't very advanced, but it is very portable.

AGI Studio is an open source program that lets users create games that are based on the AGI engine. AGI Studio is designed for Windows. There is a version for Linux called QT AGI Studio (formerly Linux AGI Studio).

WinAGI Game Development System is a new development system that allows you to create AGI based games. It includes many significant tools and features that can't be found in AGI Studio. AGI game creation is made significantly easier with WinAGI.

GBAGI is an AGI game interpreter for Game Boy Advance.

ScummVM recently gained support for AGI games by merging the Sarien code. ScummVM works on a wide variety of platforms including Linux/Unix (BSD and several others), Microsoft Windows, Mac OS X, Sega Dreamcast, AmigaOS, MorphOS, PlayStation 2, PlayStation Portable, Nintendo DS, GP32, Palm OS, Windows Mobile/CE and GP2X.