Custom Variables

Custom variables feature allows creating user-specified variables, modify and use them to drive conditional execution of naninovel scripts or other systems. For example, custom variables can be used to select one of the multiple naninovel scripts to play (scenario routes), based on the decisions player has made in the past. Another frequently used scenario is player stats screen (eg, scores, money, resources etc), based on the choices the player makes throughout the game.

NOTE

Variable name should start with a letter and can contain only latin characters, numbers and underscores, eg: name, Char1Score, my_score; the names are case-insensitive, eg: myscore is equal to MyScore.

Custom variables can be created, modified and used both in naninovel scripts via @set and @if commands and in the C# scripts using ICustomVariableManager engine service.

For example, the following script command will assign a different value to score custom variable, based on the choice:

@choice "I'm humble, one is enough..." set:score=1
@choice "Two, please." set:score=2
@choice "I'll take your entire stock!" set:score=999

And the following one will re-route the script execution based on the value of the score variable:

@goto MainRoute if:"score > 1 && score <= 900"
@goto BadEnd if:score>900

See the API reference on @set and @if commands for more examples.

All the custom variables are automatically saved with the game. By default, the variables are stored in local scope. This means, that if you assign some variable in the course of gameplay and player starts a new game or loads another saved game slot, where that variable wasn't assigned — the value will be lost. This is useful for the most type of variables. If, however, you wish to store the variable in global scope, prepend G_ or g_ to its name, eg: G_FinishedMainRoute or g_total_score. Global variables can be used to indicate some meta or total information, for example, the number of times player has finished some route or a total score based on all the playthroughs.

You can set pre-defined custom variables (both global and local) with initial values in the "Custom Variables" configuration menu.

Global pre-defined variables are initialized on first application start, while the locals do so on each state reset. Notice, that the value field in the menu expects a valid script expression and not a raw value string.

TIP

In case you want to make a kind of global counter, that will only increment once, even when re-played (eg, with rollback or after restarting the game), use HasPlayed() expression function:

@set g_GlobalCounter++ if:!HasPlayed()

Injecting Variables

It's possible to inject (inline) custom variable to naninovel script parameter values using the curly braces.

The following script will show an input field UI where user can enter an arbitrary text. Upon submit the entered text will be assigned to the specified custom variable.

; Allow user to enter an arbitrary text and assign it to `name` variable.
@input name summary:"Choose your name."
; Stop is required to halt script execution until user submits the input.
@stop

; You can then inject the assigned `name` variable in naninovel scripts.
Archibald: Greetings, {name}!

; ...or use it inside set and conditional expressions.
@set score+=3 if:name=="Felix"

TIP

To make character names dynamic, use display name feature.

You can inject the custom variables to any parameter values as long as the type allows. Eg, you can't assign a string (text) to an integer (number) parameter.

@set PlayerName="Felix";PlayerYPosition=0.1;PlayerTint="lightblue"

; The following will produce an error, as `PlayerTint` is not a number.
@char {PlayerName} pos:50,{PlayerTint}

; ...and this will execute just fine.
@char {PlayerName} pos:50,{PlayerYPosition} tint:{PlayerTint}

Variable Triggers

When building a custom UI or other systems, you may want to listen for (react to) events when a variable's value changes. For example, when creating a character stats screen, you might want the text to update with the variables. While the conventional way to implement such behavior is by using a C# script, you can also use the Custom Variable Trigger component. This component will invoke Unity events when a variable with a specified name changes.

EXAMPLE

Find example on using variable triggers to drive availability of map locations in the map sample.

Variables Debug

While the game is running it's possible to view all the existing variables and change their values for debugging purposes.

Open development console and enter var command to open the variables editor window.

When changing value of a variable in the list, a "SET" button will appear, which you can press to apply the changes.

The variables list is automatically updated when the custom variables are changed while running the game.

Using Custom Variables in C#

The custom variables can be accessed in C# via ICustomVariableManager engine service.

To get a variable value use GetVariableValue(name) method and SetVariableValue(name, value) to set variable value; eg, given a "MyVarName" custom string variable exists, the below code will retrieve it, append "Hello!" string to the value and set it back.

var varManager = Engine.GetService<ICustomVariableManager>();
var myValue = varManager.GetVariableValue("MyVarName");
myValue += "Hello!";
varManager.SetVariableValue("MyVarName", myValue);

Be aware, that all the custom variable values are stored as strings. If you want to use them as other types (eg, integer, boolean, etc), you have to parse the returned string values to the desired type and cast them back to strings when setting the values. For most common data types extension methods are available, eg:

var varManager = Engine.GetService<ICustomVariableManager>();

varManager.TryGetVariableValue<float>("MyFloatVarName", out var floatValue);
Debug.Log($"My float variable value: {floatValue}");

varManager.TryGetVariableValue<int>("MyIntVarName", out var intValue);
Debug.Log($"My integer variable value: {intValue}");

varManager.TryGetVariableValue<bool>("MyBoolVarName", out var boolValue);
Debug.Log($"My boolean variable value: {boolValue}");

floatValue += 10.5f;
varManager.TrySetVariableValue("MyFloatVarName", floatValue);

intValue = -55;
varManager.TrySetVariableValue("MyIntVarName", intValue);

boolValue = !boolValue;
varManager.TrySetVariableValue("MyBoolVarName", boolValue);