Difference between revisions of "Scripting Oolite with JavaScript"

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(Changed properties/instance variables to consistently start with lowercase, which is more consistent with normal JS usage, PList script usage and ObjC usage. Also changed initialise to initialize.)
m (changed world-scripts.plist to a link)
 
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== JavaScript file format ==
+
[[Oolite]] 1.68 and later supports scripts written in [http://en.wikipedia.org/wiki/ECMAScript ECMAScript] (more commonly known as [http://en.wikipedia.org/wiki/JavaScript JavaScript]) in addition to its traditional model based on [[property lists]]. This page provides an overview of how JavaScript is used in Oolite. The page [[Oolite JavaScript Reference: object model]] provides reference for Oolite-specific objects and methods. The page [[Oolite JavaScript Reference: World script event handlers]] provides reference for the event handlers Oolite supports. The language standards and some tutorials can be found through the Wiki links provided above.
  
To use JavaScript for an OXP, place a file script.js in the OXP's Config directory. Do not also include a script.plist or script.oos file.
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== Using JavaScript ==
  
OXP scripts written in JavaScript are "event driven" - different functions of the script are called in response to state changes in the game, or when other events of interest happen.
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Currently, JavaScript is supported for “worldScripts”, that is, as a replacement for scripts in ''script.plist'' and shipScripts, that acts as expansion for the ships AI. While a ''script.plist'' file may contain any number of separate scripts, a single JavaScript file may contain only one script.
  
Sometimes the event function will be called periodically, such as <tt>STATUS_DOCKED</tt> and <tt>STATUS_IN_FLIGHT</tt>. These functions will be called about every 10 seconds as long as the game is in that state.
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If your OXP only uses one script, place a JavaScript file named ''script.js'' (or ''script.es'') in the OXP’s ''Config'' directory. If you wish to use multiple scripts, you may instead create file named ''world-scripts.plist'' in the ''Config'' directory. This [[property list]] file should consist of an array of worldScript names; the named scripts should exist in a directory named ''Scripts'' inside your OXP. As with most “atomic” files (files which cannot be merged), such script files must have a unique name to avoid conflicts with other OXPs. Using the [[world-scripts.plist]] method, you can combine JavaScript, plist and OOS scripts however you wish.
  
Other event functions will only be called when that state becomes true, like <tt>KeyPressed</tt> and <tt>STATUS_EXITING_WITCHSPACE</tt>.
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Whereas plist scripts are based on polling – all scripts are run at semi-regular intervals, whether they need to be or not – scripts written in JavaScript are “event driven” – different functions, or ''event handlers'', in the script are called in response to state changes in the game, or when other events of interest happen. For instance, <code>willExitWitchSpace</code> is called just before player exits witchspace, and <code>alertConditionChanged</code> is called whenever the alert condition changes. See the [[Oolite JavaScript event handler reference|event handler reference]] for a full list of handlers and when Oolite will call them.
  
  
 
=== script.js File Template ===
 
=== script.js File Template ===
  
Copy and paste this template into a file called script.js in the OXP Config directory. Ensure you change at least the Name value.
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Copy and paste this template into a file called script.js in the OXP Config directory. Ensure you change at least the Name value. '''Every script must have a unique name.''' If multiple scripts with the same name are encountered, Oolite will arbitrarily select one and discard the others.
  
<pre>
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<pre>this.name          = "My OXP Script";
this.name = "OXPName"
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this.author        = "Your Name Here";
this.description = "A description of what the OXP does."
+
this.copyright      = "(C) 2013 Me.";
this.version = "1.0"
+
this.licence        = "CC-NC-by-SA 2.0";
 +
this.description   = "This OXP doesn't do very much yet.";
 +
this.version       = "1.0 alpha 1";
  
// You can copy and paste this function and just change the "initialize"
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"use strict";
// to another event name to handle other OXP events (eg "STATUS_DOCKED",
+
 
// "alertConditionChanged", etc).
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/You can copy and paste this function and just change the "startUp"
//
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    to another event name to handle other OXP events (eg "shipDockedWithStation",
this. initialize = function () {
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    "alertConditionChanged", etc).
     Log("Initialising OXP " +name)
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*/
 +
this.startUp = function()
 +
{
 +
     log(this.name, "Initialising OXP " + this.name);
 
}
 
}
 
</pre>
 
</pre>
  
=== Scripting Events ===
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== See Also ==
 
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* [https://developer.mozilla.org/en/JavaScript/Reference Mozilla JavaScript reference pages]
The following events are available to OXP scripts written in JavaScript.
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* [[Oolite JavaScript event handler reference]]
 
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* [[Oolite JavaScript object model]]
==== initialize ====
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<!-- * [[JavaScript test OXP]] -->
 
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* [[Variables in Oolite JavaScripts]]
The <tt>initialize</tt> event is called after all OXPs have been loaded. It can be used to do once-off initialisation such as registering to listen for certain keystrokes etc.
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* [[Javascript Operators]]
 
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* [[Handling OXP Dependencies with JavaScript]]
this.initialize = function () {
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* [[Optimization tips]]
}
 
 
 
 
 
==== keyPressed ====
 
 
 
''' Broken due to merge from trunk '''
 
 
 
The <tt>keyPressed</tt> event is called when a key the OXP is listening for has been pressed. It will be called once for each time the key is pressed, and will not be called again until the key is released and then pressed again.
 
 
 
The <tt>keycode</tt> argument gives the keycode of the key that was pressed. This can be used to determine which key was pressed if the OXP is listening for more than one key.
 
 
 
this.keyPressed = function (keycode) {
 
}
 
 
 
==== alertConditionChanged ====
 
 
 
The <tt>alertConditionChanged</tt> event is called when the alert condition changes. The current alert condition can be read from <tt>Player.AlertCondition</tt> and the current alert flags can be read from <tt>Player.AlertFlags</tt>.
 
 
 
this.alertConditionChanged = function (keycode) {
 
}
 
 
 
 
 
==== STATUS_DOCKED ====
 
 
 
The <tt>STATUS_DOCKED</tt> event is called periodically while the player is docked at a station or other entity with a docking port.
 
 
 
this.STATUS_DOCKED = function () {
 
}
 
 
 
 
 
==== STATUS_IN_FLIGHT ====
 
 
 
The <tt>STATUS_IN_FLIGHT</tt> event is called periodically while the player is flying in normal space or interstellar space (due to a misjump).
 
 
 
this.STATUS_IN_FLIGHT = function () {
 
}
 
 
 
 
 
==== STATUS_LAUNCHING ====
 
 
 
The <tt>STATUS_LAUNCHING</tt> event is called once when the player has launched from a dock.
 
 
 
this.STATUS_LAUNCHING = function () {
 
}
 
 
 
 
 
==== STATUS_EXITING_WITCHSPACE ====
 
 
 
The <tt>STATUS_EXITING_WITCHSPACE</tt> event is called once when the player arrives in a new system.
 
  
this.STATUS_EXITING_WITCHSPACE = function () {
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[[Category:Oolite]]
}
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[[Category:Oolite scripting]]

Latest revision as of 20:49, 20 June 2020

Oolite 1.68 and later supports scripts written in ECMAScript (more commonly known as JavaScript) in addition to its traditional model based on property lists. This page provides an overview of how JavaScript is used in Oolite. The page Oolite JavaScript Reference: object model provides reference for Oolite-specific objects and methods. The page Oolite JavaScript Reference: World script event handlers provides reference for the event handlers Oolite supports. The language standards and some tutorials can be found through the Wiki links provided above.

Using JavaScript

Currently, JavaScript is supported for “worldScripts”, that is, as a replacement for scripts in script.plist and shipScripts, that acts as expansion for the ships AI. While a script.plist file may contain any number of separate scripts, a single JavaScript file may contain only one script.

If your OXP only uses one script, place a JavaScript file named script.js (or script.es) in the OXP’s Config directory. If you wish to use multiple scripts, you may instead create file named world-scripts.plist in the Config directory. This property list file should consist of an array of worldScript names; the named scripts should exist in a directory named Scripts inside your OXP. As with most “atomic” files (files which cannot be merged), such script files must have a unique name to avoid conflicts with other OXPs. Using the world-scripts.plist method, you can combine JavaScript, plist and OOS scripts however you wish.

Whereas plist scripts are based on polling – all scripts are run at semi-regular intervals, whether they need to be or not – scripts written in JavaScript are “event driven” – different functions, or event handlers, in the script are called in response to state changes in the game, or when other events of interest happen. For instance, willExitWitchSpace is called just before player exits witchspace, and alertConditionChanged is called whenever the alert condition changes. See the event handler reference for a full list of handlers and when Oolite will call them.


script.js File Template

Copy and paste this template into a file called script.js in the OXP Config directory. Ensure you change at least the Name value. Every script must have a unique name. If multiple scripts with the same name are encountered, Oolite will arbitrarily select one and discard the others.

this.name           = "My OXP Script";
this.author         = "Your Name Here";
this.copyright      = "(C) 2013 Me.";
this.licence        = "CC-NC-by-SA 2.0";
this.description    = "This OXP doesn't do very much yet.";
this.version        = "1.0 alpha 1";

"use strict";

/*  You can copy and paste this function and just change the "startUp"
    to another event name to handle other OXP events (eg "shipDockedWithStation",
    "alertConditionChanged", etc).
*/
this.startUp = function()
{
    log(this.name, "Initialising OXP " + this.name);
}

See Also