Age of Mythology

1
Age of Mythology

• Scripting Guide

2
Outline

• Game overview
• Adding your agent to the game
• Renaming your agent
• AI vs. AI were almost there
• AI vs. AI setup
• Setting up the AI debugger
• Scripting overview
• AI library reference
• Sample code from default AI
• Explanation of sample code
• Link to AoM scripting website

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Game overview

• Age of Mythology is a real-time-strategy game
  where players start by choosing one of three
  civilizations the Greek, the Egyptian, or the
  Norse. Players choose the gods they wish to
  worship, and each god provides different
  strengths for the player's civilization. Players
  then wage war against other armies and must lead
  their civilization to victory by managing their
  civilizations military and economy.
• In addition, the game allows you to create AI
  scripts that control the computer players which
  you play against in the game. This guide shows
  how to set up Age of Mythology for AI scripting,
  how to play AI vs. AI games, and provides a brief
  description of AoM scripting.

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Adding your agent to the game

• The code for your agent is saved as a .xs file
  (e.g. admiral.xs).
• Your agent appears in the player-select drop down
  menu when you add the .xml file.
• To add your agent to the game simply
• Add your xs file to AoM's AI folder.
• Add your xml file to AoM's AI folder.
• If you want to rename your agent, youll need to
  edit the xml file as shown in the next slide.

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Renaming your agent

• To rename your agent you need to edit your xml
  file, it should look something like this
• ltAIgt
• ltscriptgtthe name of your xs file without the
  file extensionlt/scriptgt
• ltnamegt the name of your agentlt/namegt
• ltplayerNamesgt
• ltnamegtthe name of your agentlt/namegt
• lt/playerNamesgt
• lt/AIgt
• For example, if our agent is admiral.xs, then we
  need an xml file to go with it. We can name it
  admiral.xml and it should look like this
• ltAIgt
• ltscriptgtadmirallt/scriptgt
• ltnamegtAdmiral AIlt/namegt
• ltplayerNamesgt
• ltnamegtAdmiral AIlt/namegt
• lt/playerNamesgt
• lt/AIgt

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AI vs. AI were almost there

• After adding your agent to the AI folder, its
  name should appear in the list of computer player
  opponents, and you can play against your agent.
• However, if you want to play AI vs. AI random map
  games then we have more work to do because AoM
  doesnt have a graphical interface for assigning
  an AI script to player 1.
• The next slide shows how to set up AI vs. AI
  matches by using a text editor such as WordPad to
  edit a .prf file, which tells the game that
  player 1 will be controlled by an AI script.

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AI vs. AI setup

• To run AI vs. AI battles you'll need to take
  these steps
• Create a new profile in the options screen, named
  AIvsAI (or anything else)
• Using that profile, start a 1v1 random map game
  (you vs. AI)
• Quit a few seconds in and exit AoM
• Open AIvsAI.prf in the users folder and scroll
  down to playerid 0 data (shown below)
• Set aiscript to your xml file
• Set type to 1
• Save AIvsAI.prf. Your playerdata section for
  playerid 0 would look like this
• ltsingleplayerrandommapdatagt
• ltplayerdatagt
• ltplayeridgt0lt/playeridgt
• ltaiscriptgtname of your xml file without
  the file extensionlt/aiscriptgt
• lttypegt1lt/typegt
• ltcivilizationgt9lt/civilizationgt
• lt/playerdatagt
• When you want to set up AI vs. AI battles select
  the AIvsAI profile.

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Setting up the AI debugger

• The following changes provide access to AI
  debugging info. Without this, if your script has
  an error the compiler will tell you, but the
  compiler will not tell you on what line it
  detected the error. To find the error type
  Alt-Shift-d. If your agent compiled
  successfully and you want to see what goes on
  behind the scenes, type Alt-q.
• Create a user.cfg file in your AoM startup
  directory, and include these three lines in it
• aiDebug
• showAIEchoes
• developer
• Create a user.con file in the AoM startup
  directory, and add this line
• map ("alt-shift-d", "root","gadgetToggle(\"XSDeb
  ugger\")")

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Scripting overview

• Age of Mythologys AI uses a new language called
  XS (expert system), which combines the simplicity
  of a rule-based system with the power of the C
  language. In XS, most of the time, you are
  sending commands to an AI library and interacting
  with this library.
• As far as syntax is concerned, XS allows you to
  declare variables, write methods, and use
  condition statements. In almost every case with
  AoM scripting you will be using the int, string,
  and float data types methods are declared and
  used in the same way that they are in C and
  there are two types of condition statements in
  the XS language, the if-else approach and the
  switch approach.

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AI library reference

• The AI library reference is a list of AoM
  variables and function calls, located in AoMs
  docs folder under the name aom ai script help
  file.rtf, you should become familiar with this
  library.
• The AI library reference provides descriptions in
  the following manner
• int aiPlanCreate( string planName, int typeName
  )
• Creates a plan of the given name and type.
• The first thing this description tells us is that
  the function aiPlanCreate returns an integer. The
  second thing we know about this function call is
  that we need to give it two parameters, a string
  and an integer. The integer it returns is the
  plans ID, which is always non-negative the
  string parameter is an arbitrary name we give to
  the plan and the integer parameter is an AoM
  constant that identifies the plan type, e.g.
  cPlanAttack or cPlanExplore.
• The next slide has sample code from the games
  default AI. Line 18 makes a call to aiPlanCreate.

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Sample code from default AI

1. //
   
2. // RULE startLandScouting
3. //
4. // grabs the first scout in the scout list and
   starts scouting with it.
5. // this rule runs just once, creates a land
   scouting plan, and disables itself.
6. //
   
7. rule startLandScouting // marks the start of the
   rule
8. minInterval 1 // ensures that this rule will
   not run more frequently than once a second
9. active // indicates that this rule starts
   out active, so it will automatically run very
   early in the game
11. //If no scout, go away.
12. if (gLandScout -1) // tests that
    gLandScout has a valid value, the value was
    assigned elsewhere
14. xsDisableSelf() // turns this rule off,
    so that we dont create a new land scouting rule
    several times a second
15. return // exits the startLandScouting
    rule
17. //Land based Scouting.
18. gLandExplorePlanIDaiPlanCreate("Explore_Land",
    cPlanExplore) // creates an explore plan, gives
    it a name, assigns plan ID to a variable

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Explanation of sample code

• Line 18 gLandExplorePlanIDaiPlanCreate("Expl
  ore_Land", cPlanExplore)
• Creates an explore plan. An explore plan merely
  assigns living units to exploration, which is
  different from creating units for exploration.
  Plans know how to perform specific tasks such as
  exploring, gathering, attacking, defending,
  fishing, and many more. Each plan created
  generates a plan ID number. Line 18 assigns the
  plans ID number to the variable
  gLandExplorePlanID. You will need the plan ID
  later on when you set the plans behavior in
  lines 21 and 22.
• Line 21 aiPlanAddUnitType(gLandExplorePlanID,
  gLandScout, 1, 1, 1)
• Assigns a unit of type gLandScout to the explore
  plan. The unit assigned to the plan is the unit
  that will explore. The arguments 1, 1, 1
  represent the need, want, and max values for the
  assigned unit.
• Line 22 aiPlanSetActive(gLandExplorePlanID)
• Activates the explore plan. At this point a unit
  of type gLandScout is exploring the map.

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Link to AoM scripting website

• A tutorial for AI scripting, written by one of
  the games programmers is available. Download
  AoM tutorial (revision 2) from the following
  website
• http//aom.heavengames.com/downloads/lister.php?ca
  tegoryai
• Another tutorial
• http//aom.heavengames.com/scendesign/advanced/ais
  cript