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AGI (Adventure Game Interpreter) was the first major interpreter used
by Sierra. With the release of King's Quest 1 in the early 80's, it
introduced the gaming world to the concept of a 3D graphical adventure
game, where the player could move a character around the screen,
behind, in front of and over objects. Other commands could be typed
in, just like a text adventure. This concept, in various forms, has
been used many many times since, by Sierra and other companies such as
Lucas Arts. It has proved
very successful and continues to be used today in games such as Larry 7.
The latest version of this document can be found at
SGML, HTML, GNU info, Postscript and ASCII formats.
If you have any questions about the individual sections in this
document, email the author of that section.
If you have documented an aspect of the interpreter, or have updated
your documentation which is already included this document, please
send it to the current maintainer (
Claudio Matsuoka) so that it can be
added in future versions. Preferred format is Linuxdoc-SGML or plain
AGI specs is intended for people writing AGI programs such as
editors, viewers and interpreters. It is not supposed to be a
beginners' introduction to AGI, or a LOGIC programming guide for
those who just want to create games (although it can serve as a
reference for more advanced LOGIC programmers). If you want to
learn the LOGIC programming language, we suggest you read the
logic section of the AGI Studio help file, and the various other
bits of documentation and tutorials available on-line.
The programming info contained in this document is mostly from the
AGDS package and uses different syntax and
terminology for the language and can be confusing if you are using
AGI Studio for your programming.
- Keyboard key names are given in fixed with font (e.g.
- Metasyntatic variables are given in italics (e.g. n).
- File names are case sensitive and given in fixed width font
- AGI resource names are given in all caps (e.g. LOGIC, VIEW).
- AGI command names are given in fixed width font (e.g.
- AGI variable n is noted as
vn or Var(n)
- AGI flag n is noted as
fn or Flag(n)
Although this document has many details about the AGI specs, a few
pieces of information are still missing:
- Savegame file format
- Some chunks of the memory organization
- Unknown view table entries
- Unknown fields in the IIgs sound header
- The release date of many AGI games
- The purpose of commands 171, 172 and 174
- The meaning of bit 0 in the argument byte
- The meaning of bytes 0--1 in the VIEW resource header
- Canonical names of commands 170--181
- Canonical variable and flag names
- More information about differences of AGI in other platforms
(Amiga, Apple II, CoCo, etc)
- Any information about Donald Duck's Playground
Version 3.0 (22 May 1999)
- Documentation converted to SGML, to allow easy conversion to
other formats such as HTML, LaTeX, GNU info or plain text.
- Typos fixed.
- Removed redundant pieces of information.
- Re-organized and re-ordered sections; added credits, audience and
- Adopted uniform notation (all code examples and function names
in fixed width font, hexadecimal numbers, characters and strings in
C format, case sensitive file names)
- ``Version control'' section renamed ``AGI interpreter versions''.
- Removed sort-by-date and interpreter version cross-reference
from ``AGI interpreter versions''.
- Added cross-references in the LOGIC commands description.
unknown181 command descriptions
- Added IIgs SOUND resource format
- Added some bits of information to
Version 2.0 (11 July 1998)
- Date corrected in section ``Game IDs''.
- Added a note on the main page explaining what AGI specs
is for. Hopefully this will reduce the confusion that
some people have been having when using this to learn the
logic programming language.
3 March 1998
- Updated section ``Game IDs'' with
some more info about game IDs and interpreter encryption.
- Corrected put and put.v commands in section Command list
(the second argument of put and the first argument of
supposed to be a vars).
27 January 1998
- Removed sections 4.2 (logic structure), 3.4 (dir/vol file
format), 6.2 (view format), 8.2 (OBJECT format) and 8.3
WORDS.TOK format). These were sections from the AGDS
documentation which contained basically the same
information as other more recent documentation in AGI
specs. Section numbers above those removed have been
- Added sections ``LOGIC syntax'' and
``Command list and argument types''.
- Replaced sections ``How the interpreter works'' and ``PICTURE
resource format'' with a better translations.
- Added more info about the AGDS package in section
``The AGDS package''.
- Updated section ``Websites and people''
- Corrected the title of section ``Version 3 resource storage''.
- Updated the URL for the windows help version of AGI specs
in section ``Introduction''.
- Fixed up a small formatting error in section ``Version differences''
(the header for one of the tables was repeated so it was removed).
5 December 1997
- Info about windows help version added to section 1.1.
- Corrections made to info on brush patterns in picture
documentation (section 5.1).
- Fixed up some small formatting errors in sections 3.4,
3.5, 4.3 and 8.4.
5 October 1997
- Section 2.7 (version control) updated.
- Section 6.1 (View format) updated.
16 September 1997
- I forgot to add the version differences section when I
converted all the documentation to HTML. It's there now.
- Fixed some problems in the index in section 3.x.
31 August 1997
- AGI specs is now available!
- A not about the dates on documents: almost all of the
original ASCII text versions of these documents did not
have a date on them, so I have put the ``last updated''
date to be 31 August 1997, which is when they first
appeared in the HTML version of AGI Specs.
The following people (and probably more) have contributed to this document.
Please contact the document maintainer to add more names to this list.
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