Development:Quests

Development

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This page is meant to provide a platform for campaign/mission programmers to merge their ideas and best practices...

Python Scripting

Scripting Basics

VS has a lot of different ways of doing one thing. Just pick the most appropriate one for the job. It supports campaigns, missions, independent fixers, quests, adventures, etc., all of them having their specific ways of hooking them up into the game.

The python code resides in the directory data4.x/modules.

Quests & Adventures

Each script requires at least those 2 elements:

• def __init__ (self): - here you initialize your script variables
• def Execute (self): - this part is executed each simulation frame; this is the place for writing the actions of the adventure.

Quests are run inside of "random_encounters.py". If it returns 1 or True, it will keep going. If it returns 0, False or None (python returns None if you don't say what to return) then the quest will stop Execute()ing and be deleted until you jump into that system again or reload.

Most of the python bindings (to the c++ engine) are listed in data4.x/modules/stub/VS.py and commented in HowTo:Edit_Missions:Python:Bindings:Python.

There are many other useful functions coded in python and distributed through various other classes.

• data4.x/modules/Vector.py contains vector manipulation functions
• data4.x/modules/universe.py has functions related to the current and adjacent systems
• data4.x/modules/unit.py provides some unit properties, methods, and actions
• data4.x/modules/launch.py is useful for spawning units in almost any place
• data4.x/modules/faction_ships.py allows for a fine creation of ship lists by type and faction, e.g. for spawning.

Some of the functions that might be of help when writing quests and adventures will be discussed further down.

Basic Quest Setup

This is how your basic empty quest file should look like (replace questname with an individual quest name):

import quest
class quest_questname (quest.quest):
    def __init__ (self):
        self.player = VS.getPlayer()
    def Execute (self):
        return 1

In order to integrate the quest into the adventure file, you'll need to also include factory class (again, replace questname with an individual quest name):

class quest_questname_factory (quest.quest_factory):
    def __init__ (self):
       quest.quest_factory.__init__ (self,"quest_questname")
    def create (self):
        return quest_questname()

And in the adventure file, add the information required to initiate the quest (replace questname with an individual quest name) to the adventures list including the sector/system names where the quest should be initiated and the call to the your quest factory class:

import quest_questname
adventures = {
   "Crucible/Cephid_17":quest_questname.quest_questname_factory(),
   }

Now, that you have the main classes set up, you are ready to start writing the quest contents.

Getting Objects

FIXME Improve/expand it.

In the script you will require to reference the objects of the universe. Here are some examples to get you started:

• self.player = VS.getPlayer() - that's you
• self.planet = unit.getUnitByName('Atlantis') - get planet Atlantis
• self.station = unit.getUnitByName('MiningBase') - get the mining base
• self.vessel= unit.getUnitByName('Ox') - get an Ox ship
• self.gf = VS.launch("Charlotte the Harlot","Robin","privateer","unit","default",1,1,(1000,10,3000),) - creates one ship of type "Robin", being of the faction "privateer", at position (1000,10,3000), which will behave like "default" and show up in the HUD as "Charlotte the Harlot"

Getting Properties

Once you have referenced the appropriate object, you want to get information about it. Again, some commented examples follow:

• self.starttime = VS.GetGameTime() - get the time since the start of the game. This is not the universe time (star date).
• self.planet.isDocked(self.player) - verify if the player is docked to the planet. Note that you need to 'read' the meaning from right to left in this case.
• self.station.getDistance(self.player) - The distance to the center of an object. Note that when landed on a planet, the distance is the actual planet radius.
• vec = self.player.Position() - assign the player's position vector to a variable

Communications

Sending messages through the comm is fairly easy:

• VS.IOmessage (0,"Oxen","all","Hi buddy.") - make the vessel send a message to all through the comm immediately (the first 0) when the script line is executed.
• VS.IOmessage (10,"You","all","Do I know you?") - makes the player send a public message through the comm 10 seconds after the script line is executed.

You can even set your own color for the messages with a html color code:

• VS.IOmessage (20,"Oxen","You","#8080FFYou don't remember me?") - prints the comm message in light blue.
  • self.txtColor="#8080FF"
  • VS.IOmessage (30,"Oxen","Privateer",self.txtColor+"I hardly can believe this") - you can even define a color variable and add it to each line.

As far as the communications go, there is a variable in cockpit that holds what the VDU screen shows as possible options. Unfortunately the communications system is not scriptable at the moment.

More Topics

FIXME Improve/expand it.

Flight Groups

You can use "flightgroup directives" to give units specific orders (which is cool if you want to generate two drones and make one blow up another)

The list of is in C++ (undocumented) but I've decided to look through the code. This should probably go to the wiki sometime

H,h (help) -- leader of flightgroup requests help. B,b (break and attack) -- default, everyone attacks like normal A,a (attack target) -- attack their current targets lowercase k -- something undocumented, says something about capships. Probably it's an order to take out capship turrets with priority, or it's a pure bomber order to attack capships and ignore fighters. F,f (flagship?) -- Ship being escorted. I would imagine that it's an order to attack a ship being escorted by the hostile faction. Alternatively, it could be an order to fly in formation. L,l -- undocumented, like F but has complicated formation rules. Could be a shortcut for "Leave" - ships heading out. E,e -- half of this is copy and pasted from L but I have no idea. I'd say it is "escort", escort a designated ship. P,p (protect)-- I want to help out

You can also add a "." to the end to ensure that the unit will not change targets on its own. Also, a capital letter overrides the AI script, and lower case will allow it to be changed.

Unfortunately I don't see any codes for acting like a sitting duck... You could try something like making it target itself, or making it target NULL (which you get by calling the constructor VS.Unit() ) and then using something like "A."

Or, just try doing a "B." and having it target you, and make sure it is friendly... then it might just fly near you.

I believe you can get it to fly places by having it target them and then force it to do unit.setFgDirective("B.") which I think forces it to act like normal and fly to this target.

Quest Testing

In order to speed up the scripting and testing for adventures that are not already Director.Missions, you can create a mission xml file and call the adventure file directly. In order for it to work properly, it must inherit the Director.Mission class *and* call its constructor. Unfortunately quests must inherit from the quest class, so you need to use a wrapper class that takes an instance of a class as an argument:

import Director
class Executor(Director.Mission):
   def __init__(self, classesToExecute):
      Director.Mission.__init__(self)
      self.classes = classesToExecute
   def Execute(self):
      for c in self.classes:
         c.Execute()

This is a very simple class, and it's similar to what privateer.py does. I'm just making it general by passing the list of classes as an argument.

Then, in the mission xml file, you need to call that class by adding the python section:

   <python>
from quest_tutorial import Executor, quest_tutorial
tmpvar=Executor([quest_tutorial()])
   </python>

Missions & Campaigns

FIXME Detailed documentation about writing campaigns and missions is required.

The first major campaign written (Jenek)

See also the forum thread (comments & feedback) when this mission was first put into SVN. FIXME Improvements/expend it?

See also

• HowTo:Edit Missions
• HowTo:Edit News
• HowTo:Add Conversations