Mission Parameters

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Mission Parameters

Overview

Mission parameters are integer values that are passed to the mission at the beginning and which are used by the mission designer to customise user experience accordingly. The parameters are set in description.ext. They can also be either manually altered by a dedicated server admin or host during ROLE ASSIGNMENT in MP lobby from available parameters menu or by including override values in dedicated server config server.cfg. In short:

  • Mission maker can set up a list of parameters for the game and set default values for each
  • Server admin or host can change default values by selecting different options from provided parameters menu
  • Server owner can additionally override the default values in server config for each mission separately

In any case, a person selecting parameters from parameters menu at the beginning of the mission has the final say what those options will be.

Param Types

There are 2 types of parameters, primary and secondary. While primary parameters are inherited from earlier versions of Arma, they are still valid and recognised by the engine.

Primary Params

Also known as param1 and param2. They are defined in the following way in description.ext, for example:

titleParam1 = "Time limit:";
textsParam1[] = {"Unlimited", "5 min", "10 min", "15 min"};
valuesParam1[] = {0, 300, 600, 900};
defValueParam1 = 900;

titleParam2 = "Score to win:";
textsParam2[] = {"Don't keep score", "50", "100", "150"};
valuesParam2[] = {0, 50, 100, 150};
defValueParam2 = 50;

Here is some info about each entry and what it means:

  • titleParam - This is the title that will be displayed in parameters menu available to server admin or host at ROLE ASSIGNMENT
  • textsParam - These are options presented to the server admin or host when they double click on the title in the parameters menu
  • valuesParam - These are the actual param values for each of the text options, that will be passed to the mission accordingly to chosen option
  • defValueParam - This is default option which would be passed to the mission if no selection was made. It must match one of the valuesParam values

The chosen option value will be stored in param1 or param2 variable (respectfully) and then broadcast to everyone as publicVariable. As mentioned before, defValueParam value can be overridden from the server config. Here is an example of such override for both params in server.cfg:

class Missions 
{
	class Mission1
	{
		template = "Mission1.Altis";
		difficulty = "Veteran";
		param1 = 600;
		param2 = 100;
	};
};

As with defValueParam provided override values must match one of the valuesParam values. The logged admin during ROLE ASSIGNMENT phase can still override even server override by selecting an option from parameters UI.

Secondary Params

You can think of the secondary params as primary params extended and wrapped in a class called Params:

class Params
{
	class name1
	{
		title = "Item 1";
		texts[] = {"One","Two","Three"};
		values[] = {1,2,3};
		default = 1;
	};
	class name2
	{
		title = "Item 2";
		texts[] = {"Ten","Twenty","Thirty"};
		values[] = {10,20,30};
		default = 20;
	};
	class name3
	{
		title = "Item 3";
		texts[] = {"One Hundred","Two Hundred","Three Hundred"};
		values[] = {100,200,300};
		default = 300;
	};
};

As you can see the structure is the same, but the names of the entries are slightly different, but consistently different (apart from default):

  • title - (same as titleParam) - This is the title that will be displayed in parameters menu available to server admin or host at ROLE ASSIGNMENT
  • texts - (same as textsParam) - These are options presented to the server admin or host when they double click on the title in the parameters menu
  • values - (same as valuesParam) - These are the actual param values for each of the text options, that will be passed to the mission accordingly to chosen option
  • default - (same as defValueParam) - This is default option which would be passed to the mission if no selection was made. It must match one of the values values

The chosen options values will be stored in paramsArray variable, in the order of appearance in the Params class and then broadcast to everyone as publicVariable. As with primary params, default value can be overridden from the server config using class names of the defined params. Here is an example of such override in server.cfg:

class Missions 
{
	class Mission1
	{
		template = "Mission1.Altis";
		difficulty = "Veteran";
		class Params
		{
			name1 = 2;
			name2 = 30;
			name3 = 100;
		};
	};
};

As override values provided must match one of the values values. The logged admin during ROLE ASSIGNMENT phase can still override the server override by selecting options from parameters UI manually.

Using Both Types

You should be careful when using both primary and secondary params in the same mission as paramsArray in this case will contain both types of parameters. For example, if just secondary params used from the example above, paramsArray would look something like this: [1,20,300]. However if both types are used at the same time, paramsArray will look something like this: [900,50,1,20,30]. The primary params are added in front of the secondary params in paramsArray.

Mission Implementation

So how does it all come together? As pointed out, params are just values that are passed over to the mission. In order to retrieve passed param value in mission use BIS_fnc_getParamValue function. For example to retrieve mission param name2:

_param = ["name2", -1] call BIS_fnc_getParamValue;

This should return 20 (in default example above) or -1 if no param with this name is found. This method is good to be used in other scripts, but there is even better way of setting mission params at the start of the mission. You can instruct the game to run a function or a script of your choice automatically by including it in the secondary Params config. Note that it is not possible to do with primary params. For example:

class Params
{
	class Daytime
	{
		title = "Time";
		texts[] = {"Morning","Day","Evening","Night"};
		values[] = {6,12,18,0};
		default = 12;
		function = "BIS_fnc_paramDaytime";
	};
};

The BIS_fnc_paramDaytime function will be executed on mission start on the server. It will also receive current value of the parameter Daytime as an argument in _this select 0. You can also instruct the game to execute a script file instead and not just on server but on every client including the JIP clients:

class Params
{
	class ViewDistance
	{
		title = "View distance (in metres)";
		values[] = {500,1000,2000,5000};
		default = 1000;
		file = "setViewDistance.sqf";
		isGlobal = 1;
	};
};

The setViewDistance.sqf script will be execVMed globally (isGlobal = 1;) on every client and param value is passed to it in _this select 0. If for some weird reason you have both function and file entries, the priority is given to function.