Variables

StoryFlow variables are the backbone of dynamic storytelling. They store state that persists throughout your story - tracking player choices, inventory, stats, and any other data your narrative depends on. This guide covers how to interact with them from Unreal Engine.

Variable Types

Every variable in a StoryFlow project carries a set of core properties:

• Id - A generated hash identifier (e.g., var_A3F8B21C). Used internally by the runtime.
• Name - The human-readable display name. This is the string you pass to getter/setter functions from Blueprint and C++.
• Type - One of the EStoryFlowVariableType enum values.
• Value - The current value, stored as an FStoryFlowVariant.
• bIsArray - Whether this variable holds a single value or an array of values.
• EnumValues - For Enum-type variables, the list of valid option strings.

EStoryFlowVariableType Enum

The plugin defines the following variable types:

FStoryFlowVariant

FStoryFlowVariant is the type-safe value container used throughout the plugin. It holds one value at a time along with its type tag, so you always know what kind of data you are working with.

Getter methods return a default if the variant holds a different type:

GetMap() was added in v1.2.0 and returns the variant's ordered key-value entries (see Maps). Note that map-typed variants render as an empty string in ToString() and in dialogue text interpolation. Display formatting for maps is deliberately deferred, so read entries through GetMap() or GetMapVariable instead.

Factory methods create a variant from a typed value:

// Create variants from typed values
FStoryFlowVariant BoolVal = FStoryFlowVariant::FromBool(true);
FStoryFlowVariant IntVal = FStoryFlowVariant::FromInt(42);
FStoryFlowVariant FloatVal = FStoryFlowVariant::FromFloat(3.14f);
FStoryFlowVariant StringVal = FStoryFlowVariant::FromString(TEXT("Hello"));

// Read values back
bool bValue = BoolVal.GetBool();     // true
int32 iValue = IntVal.GetInt();       // 42
float fValue = FloatVal.GetFloat();   // 3.14
FString sValue = StringVal.GetString(); // "Hello"

// ToString() for display / logging
FString Display = IntVal.ToString();  // "42"

// Array support
TArray<FStoryFlowVariant> Items;
Items.Add(FStoryFlowVariant::FromInt(1));
Items.Add(FStoryFlowVariant::FromInt(2));
FStoryFlowVariant ArrayVal;
ArrayVal.SetArray(Items);
TArray<FStoryFlowVariant> Retrieved = ArrayVal.GetArray();

Local vs Global Scope

StoryFlow variables exist in one of two scopes, and the scope determines their lifetime and visibility:

// Reading a local variable (scoped to this component's current script)
bool bHasKey = StoryFlowComponent->GetBoolVariable("hasKey", false);

// Reading a global variable (shared across all components)
int32 PlayerGold = StoryFlowComponent->GetIntVariable("playerGold", true);

Reading Variables

The UStoryFlowComponent exposes typed getter functions for reading variable values. All functions are available in both Blueprint and C++ under the category StoryFlow|Variables.

Each function looks up the variable by its display name in either the local (component) or global (subsystem) store, then returns the value cast to the appropriate type. If the variable is not found, the type's default value is returned.

// C++ examples
UStoryFlowComponent* SF = GetOwner()->FindComponentByClass<UStoryFlowComponent>();

// Local variables
bool bQuestComplete = SF->GetBoolVariable("questComplete", false);
FString PlayerName = SF->GetStringVariable("playerName", false);

// Global variables
int32 Gold = SF->GetIntVariable("playerGold", true);
float Reputation = SF->GetFloatVariable("reputation", true);
FString Difficulty = SF->GetEnumVariable("difficulty", true);

String Table Resolution

GetStringVariable and GetEnumVariable route their return value through the project's string table using the component's LanguageCode. When the stored value is a string-table key, the caller receives the localized display text rather than the raw key. When the stored value is not a string-table key, it passes through unchanged.

This means that two variables, one assigned a key like "npc.elder.greeting" and another assigned a literal string like "Hello", are both safe to read from the same call site. Localized authoring in the StoryFlow Editor reaches your Unreal UI without an extra resolution step on your side. Setters do not perform any string-table lookup. Values are stored verbatim.

// Stored value is a string-table key like "npc.elder.greeting"
// GetStringVariable returns the localized text such as "Welcome, traveler."
FString Greeting = SF->GetStringVariable("elderGreeting", true);

// Stored value is a literal string like "Bandit Hideout"
// GetStringVariable passes it through unchanged
FString Location = SF->GetStringVariable("currentLocation", true);

Setting Variables

The component also exposes typed setter functions. Like the getters, these are available under the StoryFlow|Variables category in Blueprints.

Setting a variable updates the value in the appropriate scope and fires the OnVariableChanged delegate (see below). This means your game logic can react immediately to any change, whether triggered by a node in the StoryFlow graph or by your own Blueprint/C++ code.

// C++ examples
UStoryFlowComponent* SF = GetOwner()->FindComponentByClass<UStoryFlowComponent>();

// Set a local boolean (e.g., after player picks up a key)
SF->SetBoolVariable("hasKey", true, false);

// Set a global integer (e.g., award gold for completing a quest)
SF->SetIntVariable("playerGold", 500, true);

// Set a global enum (e.g., change difficulty at runtime)
SF->SetEnumVariable("difficulty", TEXT("Hard"), true);

OnVariableChanged Delegate

Every time a variable changes - whether from node execution inside the StoryFlow graph or from a direct Blueprint/C++ call - the OnVariableChanged delegate fires.

Signature:

DECLARE_DYNAMIC_MULTICAST_DELEGATE_TwoParams(
    FOnVariableChanged,
    const FStoryFlowVariable&, Variable,
    bool, bIsGlobal
);

Parameters:

• Variable - The full FStoryFlowVariable struct containing Id, Name, Type, Value, and other metadata. Break the struct pin in Blueprint to access individual fields.
• bIsGlobal - Whether the change occurred in the global scope.

Binding in C++:

// In your actor's BeginPlay
UStoryFlowComponent* SF = FindComponentByClass<UStoryFlowComponent>();
SF->OnVariableChanged.AddDynamic(this, &AMyActor::HandleVariableChanged);

// Handler
void AMyActor::HandleVariableChanged(const FStoryFlowVariable& Variable, bool bIsGlobal)
{
    if (Variable.Name == "playerGold")
    {
        int32 NewGold = Variable.Value.GetInt();
        UpdateGoldUI(NewGold);
    }

    // You can also check by type or internal Id:
    // Variable.Id    - internal hash identifier
    // Variable.Type  - EStoryFlowVariableType enum
}

For character variable mutations including Name, Image and any custom field, use OnCharacterVariableChanged. See Characters.

Variable Interpolation in Dialogue

Dialogue text in StoryFlow can reference variables using the {varname} syntax. When the runtime builds the dialogue state, it automatically replaces these tokens with the current variable values.

// In the StoryFlow Editor dialogue node text:
"You have {playerGold} gold coins, {playerName}."

// At runtime, if playerGold = 500 and playerName = "Alice":
"You have 500 gold coins, Alice."

Interpolation is resolved automatically when the OnDialogueUpdated delegate fires. You do not need to perform any manual string replacement - the text in the dialogue state is already fully resolved.

Arrays

Variables can be arrays (bIsArray = true). An array variable holds an ordered list of FStoryFlowVariant values, all of the same type. Arrays are supported for Bool, Int, Float, String, Image, Character and Audio variables. The editor does not offer enum arrays.

Array Operations

The StoryFlow node graph provides a full set of array manipulation nodes. These operations execute as part of the story flow and update the variable automatically:

The forEach loop node iterates over all elements in an array, executing the connected subgraph once per element. This is useful for processing inventories, applying effects to party members, or evaluating a list of quest objectives.

Reading Array Variables

The UStoryFlowComponent exposes GetArrayVariable(VariableName, bGlobal) as a one-call way to read any array variable as a TArray<FStoryFlowVariant>. The same string-table resolution rules from String Table Resolution apply per element: String and Enum elements are routed through the string table using the component's LanguageCode, while Image, Audio and Character elements pass through as raw keys.

When bGlobal is false the function searches local script variables first, then falls back to globals. When bGlobal is true the function searches globals only. The function returns an empty array if the variable is missing or is not an array.

UStoryFlowComponent* SF = GetOwner()->FindComponentByClass<UStoryFlowComponent>();

// Read a local array of inventory item names (strings)
TArray<FStoryFlowVariant> Items = SF->GetArrayVariable(TEXT("inventory"));
for (const FStoryFlowVariant& Item : Items)
{
    UE_LOG(LogTemp, Log, TEXT("Inventory: %s"), *Item.GetString());
}

// Read a global array of quest stage numbers (ints)
TArray<FStoryFlowVariant> Stages = SF->GetArrayVariable(TEXT("completedStages"), true);
for (const FStoryFlowVariant& Stage : Stages)
{
    int32 StageNumber = Stage.GetInt();
    // ...
}

For a character-typed array variable, use GetCharacterArrayVariable(VariableName) on the component instead. It returns TArray<FString> character paths ready to pass into the character APIs. See Character Lists.

Maps

Added in v1.2.0. A map variable holds an ordered list of key-value entries. Keys can be String, Integer or Enum typed and values can be any scalar variable type. Entry order is preserved exactly as the StoryFlow Editor serializes it, so key listings, value listings and iteration order match the editor's HTML runtime.

Map Operations

The node graph provides ten map operation nodes. Like the array nodes, they execute as part of the story flow and update the variable automatically:

The forEachMap loop node iterates over a map's entries, executing the connected subgraph once per entry. The entry list is snapshotted once when the loop starts, and each iteration exposes the current key and value as loop outputs for the body to read. Mutations inside the body land on the live map but do not skip, repeat or extend iteration.

setMap Aliasing

Assigning one map variable to another with setMap aliases the live storage instead of copying it. After the assignment, both variables observe the same entries: mutating or clearing the map through either variable is visible through the other. This matches the reference semantics of the editor's HTML runtime.

Aliases are detached at asset-to-runtime copy boundaries. When script locals, subsystem globals or runtime characters are copied out of an imported asset, every map variable receives fresh storage, so runtime mutations never write into the script asset and never leak between runs.

Reading Map Variables

The UStoryFlowComponent exposes GetMapVariable(VariableName, Keys, Values, bGlobal) to read a map variable from Blueprint or C++. It returns the entries as two parallel TArray<FStoryFlowVariant> output arrays where Keys[i] pairs with Values[i], in the map's entry order. String and Enum values are resolved through the string table using the component's LanguageCode so callers receive localized text, while keys stay raw identifiers and never resolve. Both arrays come back empty if the variable is missing or is not a map.

UStoryFlowComponent* SF = GetOwner()->FindComponentByClass<UStoryFlowComponent>();

// Read a global map of quest names keyed by quest id
TArray<FStoryFlowVariant> Keys;
TArray<FStoryFlowVariant> Values;
SF->GetMapVariable(TEXT("questLog"), Keys, Values, true);

// Keys[i] pairs with Values[i], in the map's entry order
for (int32 i = 0; i < Keys.Num(); ++i)
{
    UE_LOG(LogTemp, Log, TEXT("Quest %s: %s"),
        *Keys[i].GetString(),    // raw key identifier
        *Values[i].GetString()); // localized display text
}

Resetting Variables

The plugin provides functions to reset variables back to their initial values as defined in the StoryFlow project. This is useful for restarting a story, resetting a scene, or clearing state for a new game.

// Reset just this component's local variables
StoryFlowComponent->ResetVariables();

// Reset global variables across all components
UStoryFlowSubsystem* Subsystem = GetGameInstance()->GetSubsystem<UStoryFlowSubsystem>();
Subsystem->ResetGlobalVariables();

// Full state reset (globals + characters + once-only options)
Subsystem->ResetAllState();