Overriding Default GameState

The SDK provides a default game state implementation through UGameEngineHandlers. The interaction and scene fields give the agent basic context:


USTRUCT()
struct FDummyGameState
{
    GENERATED_BODY()
 
    UPROPERTY()
    bool _can_interact = true;
 
    UPROPERTY()
    FString current_scene;
};

These fields serve specific purposes:

_can_interact: Tells the AI agent whether it can interact with the game
current_scene: The name of the current scene that the agent can actually see

Fields prefixed with underscore (like _can_interact) are used internally by the framework.

Creating a Custom Game State

Let’s look at a practical example of overriding the default game state with Lyra-specific information:


USTRUCT()
struct FLyraNunuGameState
{
    GENERATED_BODY()
 
    // Framework fields (required)
    UPROPERTY()
    bool _can_interact = true;
 
    // Game-specific fields
    UPROPERTY()
    FString current_map;
 
    UPROPERTY()
    FString my_name;
 
    UPROPERTY()
    uint8 my_team;
 
    UPROPERTY()
    FString my_health;
 
    UPROPERTY()
    FString my_kda;
 
    UPROPERTY()
    TArray<FLyraWeapon> my_weapons;
 
    UPROPERTY()
    FString my_location;
 
    UPROPERTY()
    TArray<FLyraOtherPlayerState> other_players;
 
    UPROPERTY()
    TArray<FLyraSpawner> spawners;
};

Implementation Example

Here’s a full example of overriding the game state:


UCLASS()
class UNunuCoreHandlers : public UFlayerFunctionLibrary
{
    GENERATED_BODY()
public:
    UNunuCoreHandlers()
    {
        // Override the default game_state function
        REGISTER_FLAYER_FUNCTION(
            HandleGameState,
            "game_state",
            "Returns detailed game state",
            "",
            false           // Not directly exposed to AI
        );
    }
 
    UFUNCTION()
    FString HandleGameState(UPacketLogger* Logger)
    {
        FLyraNunuGameState GameState;
 
        UWorld* World = GetWorld();
        if (!World)
        {
            return TEXT("{}");
        }
 
        // Set basic state
        FString CurrentLevelName = World->GetMapName();
        GameState.current_map = CurrentLevelName;
 
        if (APlayerCharacter* Character = GetPlayerCharacter())
        {
            // Set interaction state
            GameState._can_interact = !Character->IsDead() &&
                                    !Character->IsInCutscene() &&
                                    !Character->IsStunned();
 
            // Get character stats
            if (UHealthComponent* Health = Character->GetHealthComponent())
            {
                GameState.my_health = FString::Printf(TEXT("%.1f/%.1f"),
                    Health->GetCurrentHealth(),
                    Health->GetMaxHealth()
                );
            }
 
            // Add weapon information
            if (UInventoryComponent* Inventory = Character->GetInventoryComponent())
            {
                for (const auto& Weapon : Inventory->GetWeapons())
                {
                    FLyraWeapon WeaponState;
                    WeaponState.weapon_name = Weapon->GetDisplayName();
                    WeaponState.ammo = FString::Printf(TEXT("%d/%d"),
                        Weapon->GetCurrentAmmo(),
                        Weapon->GetMaxAmmo()
                    );
                    WeaponState.equipped = (Weapon == Inventory->GetActiveWeapon());
 
                    GameState.my_weapons.Add(WeaponState);
                }
            }
        }
 
        // Process other players
        TArray<AActor*> OtherPlayers;
        UGameplayStatics::GetAllActorsOfClass(World, APlayerCharacter::StaticClass(), OtherPlayers);
 
        for (AActor* Actor : OtherPlayers)
        {
            if (APlayerCharacter* OtherPlayer = Cast<APlayerCharacter>(Actor))
            {
                // Skip if this is our character
                if (OtherPlayer == GetPlayerCharacter())
                {
                    continue;
                }
 
                FLyraOtherPlayerState PlayerState;
                PlayerState.player_name = OtherPlayer->GetPlayerName();
                PlayerState.player_location = UFlayerFunctionUtils::VectorToString(
                    OtherPlayer->GetActorLocation()
                );
 
                // Add additional player info...
                GameState.other_players.Add(PlayerState);
            }
        }
 
        // Convert to JSON
        FString JsonOutput;
        FJsonObjectConverter::UStructToJsonObjectString(GameState, JsonOutput);
        return JsonOutput;
    }
};