Adventure Game Interpreter
Encyclopedia
The Adventure Game Interpreter (AGI) is a game engine
which Sierra On-Line
used through most of the 1980s to create and run animated, color adventure game
s. AGI-based computer games accept typed commands via keyboard
, as well as joystick
input.
In 1983, IBM commissioned Sierra On-Line to develop a game that would showcase the technical capabilities of the IBM PCjr
, a home computer which IBM planned to release the following year. To meet the challenge, game designer Roberta Williams
scripted a game that was to become King's Quest: Quest for the Crown, and lead developer Arthur Abraham developed a custom programming language
called Game Assembly Language. After Sierra dismissed Abraham, IBM contributed to the development of King's Quests game engine in order to help ensure the project's success.
The PCjr proved unpopular in the marketplace, and the May 1984 launch of King's Quest foundered. Nevertheless, later that year Tandy Corporation
released the Tandy 1000
, another IBM PC compatible
that had originally been designed as an enhanced clone of the PCjr and which succeeded where the PCjr failed. King's Quest caused a sensation in the burgeoning market of PC-compatible computers, and Sierra eventually sold more than half a million copies.
Roberta Williams' King's Quest established a new type of interactive adventure game, and Sierra named their new game engine the Adventure Game Interpreter. Following the success of King's Quest, they ported the game (AGI included) to other computing platforms, such as the Apple II
, Apple IIGS
, Apple Macintosh, Amiga
and Atari ST
.
Although the 160x200 display resolution
of AGI-based games was tailored for the PCjr, it persisted as an AGI standard on other platforms as well. However, Sierra adapted the color palette
for other video hardware.
In 1988, with the release of King's Quest IV: The Perils of Rosella
, Sierra debuted a more sophisticated proprietary game engine: Sierra's Creative Interpreter
, or SCI. Since the SCI engine required a more powerful home computer, Sierra released an AGI version of the game at the same time. However, Sierra overestimated consumer demand for the lesser version, and ceased production.
The following year, Sierra published its final AGI-based title, Manhunter 2: San Francisco
, then focused exclusively on SCI for new adventure game development. Among SCI's enhancements were a more versatile scripting system, an object-oriented programming
model, higher-resolution graphics (320x200 rather than 160x200), a point-and-click
interface, and support for additional sound card
hardware.
Game engine
A game engine is a system designed for the creation and development of video games. There are many game engines that are designed to work on video game consoles and personal computers...
which Sierra On-Line
Sierra Entertainment
Sierra Entertainment Inc. was an American video-game developer and publisher founded in 1979 as On-Line Systems by Ken and Roberta Williams...
used through most of the 1980s to create and run animated, color adventure game
Adventure game
An adventure game is a video game in which the player assumes the role of protagonist in an interactive story driven by exploration and puzzle-solving instead of physical challenge. The genre's focus on story allows it to draw heavily from other narrative-based media such as literature and film,...
s. AGI-based computer games accept typed commands via keyboard
Keyboard (computing)
In computing, a keyboard is a typewriter-style keyboard, which uses an arrangement of buttons or keys, to act as mechanical levers or electronic switches...
, as well as joystick
Joystick
A joystick is an input device consisting of a stick that pivots on a base and reports its angle or direction to the device it is controlling. Joysticks, also known as 'control columns', are the principal control in the cockpit of many civilian and military aircraft, either as a center stick or...
input.
In 1983, IBM commissioned Sierra On-Line to develop a game that would showcase the technical capabilities of the IBM PCjr
IBM PCjr
The IBM PCjr was IBM's first attempt to enter the home computer market. The PCjr, IBM model number 4860, retained the IBM PC's 8088 CPU and BIOS interface for compatibility, but various design and implementation decisions led the PCjr to be a commercial failure.- Features :Announced November 1,...
, a home computer which IBM planned to release the following year. To meet the challenge, game designer Roberta Williams
Roberta Williams
Roberta Williams is an American video game designer. She is most famous for her pioneering work in graphical adventure games, particularly the King's Quest series.-Career:...
scripted a game that was to become King's Quest: Quest for the Crown, and lead developer Arthur Abraham developed a custom programming language
Programming language
A programming language is an artificial language designed to communicate instructions to a machine, particularly a computer. Programming languages can be used to create programs that control the behavior of a machine and/or to express algorithms precisely....
called Game Assembly Language. After Sierra dismissed Abraham, IBM contributed to the development of King's Quests game engine in order to help ensure the project's success.
The PCjr proved unpopular in the marketplace, and the May 1984 launch of King's Quest foundered. Nevertheless, later that year Tandy Corporation
Tandy Corporation
Tandy Corporation was a family-owned leather goods company based in Fort Worth, Texas. Tandy was founded in 1919 as a leather supply store, and acquired RadioShack in 1963. The Tandy name was dropped in May 2000, when RadioShack Corporation was made the official name.-History:Tandy began in 1919...
released the Tandy 1000
Tandy 1000
The Tandy 1000 was the first in a line of more-or-less IBM PC compatible home computer systems produced by the Tandy Corporation for sale in its Radio Shack chain of stores.-Overview:...
, another IBM PC compatible
IBM PC compatible
IBM PC compatible computers are those generally similar to the original IBM PC, XT, and AT. Such computers used to be referred to as PC clones, or IBM clones since they almost exactly duplicated all the significant features of the PC architecture, facilitated by various manufacturers' ability to...
that had originally been designed as an enhanced clone of the PCjr and which succeeded where the PCjr failed. King's Quest caused a sensation in the burgeoning market of PC-compatible computers, and Sierra eventually sold more than half a million copies.
Roberta Williams' King's Quest established a new type of interactive adventure game, and Sierra named their new game engine the Adventure Game Interpreter. Following the success of King's Quest, they ported the game (AGI included) to other computing platforms, such as the Apple II
Apple II
The Apple II is an 8-bit home computer, one of the first highly successful mass-produced microcomputer products, designed primarily by Steve Wozniak, manufactured by Apple Computer and introduced in 1977...
, Apple IIGS
Apple IIGS
The Apple , the fifth and most powerful model in the Apple II series of personal computers produced by Apple Computer. The "GS" in the name stands for Graphics and Sound, referring to its enhanced graphics and sound capabilities, both of which greatly surpassed previous models of the line...
, Apple Macintosh, Amiga
Amiga
The Amiga is a family of personal computers that was sold by Commodore in the 1980s and 1990s. The first model was launched in 1985 as a high-end home computer and became popular for its graphical, audio and multi-tasking abilities...
and Atari ST
Atari ST
The Atari ST is a home/personal computer that was released by Atari Corporation in 1985 and commercially available from that summer into the early 1990s. The "ST" officially stands for "Sixteen/Thirty-two", which referred to the Motorola 68000's 16-bit external bus and 32-bit internals...
.
Although the 160x200 display resolution
Display resolution
The display resolution of a digital television or display device is the number of distinct pixels in each dimension that can be displayed. It can be an ambiguous term especially as the displayed resolution is controlled by all different factors in cathode ray tube , flat panel or projection...
of AGI-based games was tailored for the PCjr, it persisted as an AGI standard on other platforms as well. However, Sierra adapted the color palette
Palette (computing)
In computer graphics, a palette is either a given, finite set of colors for the management of digital images , or a small on-screen graphical element for choosing from a limited set of choices, not necessarily colors .Depending on the context In computer graphics, a palette is either a given,...
for other video hardware.
In 1988, with the release of King's Quest IV: The Perils of Rosella
King's Quest IV: The Perils of Rosella
King's Quest IV: The Perils of Rosella, released in 1988, was the first major graphical computer adventure game with a female protagonist. The player takes on the role of Princess Rosella, daughter of King Graham of Daventry and the twin sister of Gwydion/Alexander...
, Sierra debuted a more sophisticated proprietary game engine: Sierra's Creative Interpreter
Sierra's Creative Interpreter
Sierra's Creative Interpreter is the scripting language created by Jeff Stephenson of Sierra On-Line for its adventure games after the older AGI, and the runtime environment for such adventure games....
, or SCI. Since the SCI engine required a more powerful home computer, Sierra released an AGI version of the game at the same time. However, Sierra overestimated consumer demand for the lesser version, and ceased production.
The following year, Sierra published its final AGI-based title, Manhunter 2: San Francisco
Manhunter 2: San Francisco
-External links:* Game Information & Screenshots* *...
, then focused exclusively on SCI for new adventure game development. Among SCI's enhancements were a more versatile scripting system, an object-oriented programming
Object-oriented programming
Object-oriented programming is a programming paradigm using "objects" – data structures consisting of data fields and methods together with their interactions – to design applications and computer programs. Programming techniques may include features such as data abstraction,...
model, higher-resolution graphics (320x200 rather than 160x200), a point-and-click
Point-and-click
Point-and-click is the action of a computer user moving a cursor to a certain location on a screen and then pressing a mouse button, usually the left button , or other pointing device...
interface, and support for additional sound card
Sound card
A sound card is an internal computer expansion card that facilitates the input and output of audio signals to and from a computer under control of computer programs. The term sound card is also applied to external audio interfaces that use software to generate sound, as opposed to using hardware...
hardware.
AGI-based games published by Sierra On-Line
- King's Quest (1984)
- King's Quest II: Romancing the ThroneKing's Quest II: Romancing the ThroneKing's Quest II: Romancing the Throne is the second installment in the King's Quest series created by Sierra Entertainment...
(1985) - The Black Cauldron (1986)
- Donald Duck's PlaygroundDonald Duck's PlaygroundDonald Duck's Playground is a computer game for the Commodore 64, based on the Walt Disney cartoon and comic book character Donald Duck. It was also ported to the IBM PCjr, Apple II, Atari ST and Amiga...
(1986) - King's Quest III: To Heir Is HumanKing's Quest III: To Heir Is HumanKing's Quest III: To Heir Is Human is the third installment in the King's Quest series of computer games produced by Sierra On-Line. It was the first game in the series not to feature King Graham as the player character....
(1986) - Space Quest: The Sarien Encounter (1986)
- Leisure Suit Larry in the Land of the Lounge LizardsLeisure Suit Larry in the Land of the Lounge LizardsLeisure Suit Larry in the Land of the Lounge Lizards is the alliterative title to an adventure computer game first released in 1987, the first part of the Leisure Suit Larry series. It was a completely graphical adventure game with 16 color EGA graphics. It utilizes the Adventure Game Interpreter ...
(1987) - Mixed-Up Mother GooseMixed-Up Mother GooseRoberta Williams' Mixed-Up Mother Goose is a computer game first released by Sierra On-Line in 1987. It is, in essence, an edutainment title, directed specifically at young gamers, as well as an adventure game.-Plot:...
(1987) - Police Quest: In Pursuit of the Death AngelPolice Quest: In Pursuit of the Death AngelPolice Quest: In Pursuit of the Death Angel is an adventure game produced by Jim Walls for Sierra On-Line, and originally released in 1987 built on their AGI.It was remade in 1992 using 256 color VGA graphics and the SCI engine....
(1987) - Space Quest II: Vohaul's RevengeSpace Quest II: Vohaul's RevengeSpace Quest II: Vohaul's Revenge was released on November 14, 1987 and it was the sequel to Space Quest: The Sarien Encounter; this game once again used Sierra's AGI.-Plot:...
(1987) - Gold Rush!Gold Rush!Gold Rush! is a graphic adventure game released by Sierra Entertainment in 1988. It was designed by Doug and Ken MacNeill. Players move a man from screen to screen, and type in simple commands to control him.-Story:...
(1988) - Manhunter: New YorkManhunter: New YorkManhunter: New York is a post-apocalyptic adventure game designed by Barry Murry, Dave Murry and Dee Dee Murry of Evryware and published in 1988 by Sierra On-Line. A sequel, Manhunter 2: San Francisco was released the next year in 1989-Scenario:...
(1988) - King's Quest IV: The Perils of RosellaKing's Quest IV: The Perils of RosellaKing's Quest IV: The Perils of Rosella, released in 1988, was the first major graphical computer adventure game with a female protagonist. The player takes on the role of Princess Rosella, daughter of King Graham of Daventry and the twin sister of Gwydion/Alexander...
(1988) - Manhunter 2: San FranciscoManhunter 2: San Francisco-External links:* Game Information & Screenshots* *...
(1989)
External links
- AGI Development Site
- AGI Studio
- The AGI Webring
- DAGII, a reimplementation of AGI by David Symonds.
- Chris's AGI Web Site
- GBAGI, a reimplementation of AGI for Game Boy AdvanceGame Boy AdvanceThe is a 32-bit handheld video game console developed, manufactured, and marketed by Nintendo. It is the successor to the Game Boy Color. It was released in Japan on March 21, 2001; in North America on June 11, 2001; in Australia and Europe on June 22, 2001; and in the People's Republic of China...
. - Kelly, Peter. "Making adventure games with AGI." AdventureClassicGaming.com. 21 January 2000.
- The Ultimate AGI & SCI Web Site (via Archive.org)
- WinAGI Game Development System
- The Sarien.net portal to play AGI games in your browser, multiplayer
- AGI/Specifications in ScummVM Wiki
- AGI Fanmade Game Message Board at ScummVM forums
- AGI Fanmade Game Message Board at sciprogramming.com forums
- AGIFANS - The home of PICEDIT and all of Lance Ewing's original AGI tools