info.nut is a file in which you tell NoAI basic things about your AI. It used to be part of main.nut, but it has been separated to make debugging easier (see here if you're interested in details).

See also http://noai.openttd.org/docs/trunk/classAIInfo.html for a better (and complete) description of all functions.

info.nut structure

The internal structure of info.nut is very simple and follows a template presented below.

class MyNewAI extends AIInfo 
{
  function GetAuthor()        { return "Newbie AI Writer"; }
  function GetName()          { return "MyNewAI"; }
  function GetDescription()   { return "An example AI by following the wiki tutorial"; }
  function GetVersion()       { return 1; }
  function MinVersionToLoad() { return 1; }
  function GetDate()          { return "2007-03-17"; }
  function GetShortName()     { return "MYAI"; }
  function CreateInstance()   { return "MyNewAI"; }
  function GetAPIVersion()    { return "1.0"; }
}

/* Tell the core we are an AI */
RegisterAI(MyNewAI());

Where of course you should change the names however you like to call everything. Just don't forget the RegisterAI(), and don't forget to extend AIInfo. If something goes wrong, check if you did: RegisterAI(MyNewAI()). Mind the () after MyNewAI!

Settings

It is possible to allow users to change settings in your AI. The only requirement is that you tell them which settings. You can do this by altering your info.nut in the following way:

class MyNewAI extends AIInfo 
{
  function GetAuthor()      { return "Newbie AI Writer"; }
  function GetName()        { return "MyNewAI"; }
  function GetDescription() { return "An example AI by following the tutorial at http://wiki.openttd.org/"; }
  function GetVersion()     { return 1; }
  function MinVersionToLoad() { return 1; }
  function GetDate()        { return "2007-03-17"; }
  function GetShortName()   { return "MYAI"; }
  function CreateInstance() { return "MyNewAI"; }
  function GetAPIVersion()  { return "1.0"; }
  
  function GetSettings() 
  {
    AddSetting(
      {
      name = "NameOfSetting", 
      description = "Description of setting", 
      min_value = 0, 
      max_value = 10, 
      easy_value = 10, 
      medium_value = 5, 
      hard_value = 0, 
      custom_value = 5, 
      flags = 0
      });
    AddLabels("NameOfSetting", {
      _0 = "It's off now", 
      _10 = "Maximum"
      });
  }
}

/* Tell the core we are an AI */
RegisterAI(MyNewAI());

The new lines of course are those about Settings. In SetSetting it is important to define all properties. If not, an error will be given. Now in the GUI on your AI there will be an option to alter NameOfSetting between the values of 0 and 10, or a preset value if your have a difficulty setting different than 'Custom'. TestAI also shows simple examples of using bool (on/off) settings.

Available parameters for AddSetting:

Flags

It's possible to combine two or more settings together. For example this makes a random boolean: flags = AICONFIG_BOOLEAN | AICONFIG_RANDOM

AddLabels

AddLabels accepts two parameters, first is the name of the setting to define labels for, and second a table with a mapping from values to labels. As identifiers can't start with a digit, the first character is ignored (the underscore in the example). The rest of the identifier should be a number you want to define a label for. In case you don't define a label, the number is shown as number. Those labels are only for the users, in your AI you'll still get the numerical values if you use GetSetting().

Reading setting values

Now inside your AI you can request the value of this setting, by doing:

MyNewAI.GetSetting("NameOfSetting");

There are a few things to remember:

• Settings never change during runtime. You set them before you start a game, and that is final. //Except setting with AICONFIG_INGAME.
• Settings are always integers.
• Changing your info.nut file while OpenTTD is running will cause the program NOT to notice that the values declared in your GetSettings() function have changed. You should restart the program (not just the game) for them to take effect.

Debug info

If your info.nut doesn't load, you won't see the errors unless you enable the debug console from the command line of the game (start game with parameters -d ai=5).