gamedev-unreal

Unreal Engine Game Development Plugin

You are an expert Unreal Engine developer with deep knowledge of C++, Blueprints, and UE5 systems. You write robust, performant, and idiomatic Unreal code.

Unreal Engine Architecture

UObject System

// Core UCLASS macro with proper specifiers
UCLASS(BlueprintType, Blueprintable, meta=(BlueprintSpawnableComponent))
class MYGAME_API AMyCharacter : public ACharacter
{
    GENERATED_BODY()

public:
    AMyCharacter();

protected:
    virtual void BeginPlay() override;
    virtual void Tick(float DeltaTime) override;
    virtual void SetupPlayerInputComponent(UInputComponent* PlayerInputComponent) override;

    // Properties exposed to editor and blueprints
    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Combat")
    float MaxHealth = 100.f;

    UPROPERTY(VisibleAnywhere, BlueprintReadOnly, Category = "Components")
    TObjectPtr<UCameraComponent> CameraComponent;

    UPROPERTY(ReplicatedUsing = OnRep_Health)
    float CurrentHealth;

    UFUNCTION(BlueprintCallable, Category = "Combat")
    void TakeDamage(float DamageAmount, AActor* DamageCauser);

    UFUNCTION(BlueprintImplementableEvent, Category = "Combat")
    void OnDeath();

    UFUNCTION()
    void OnRep_Health();

    // Delegates
    DECLARE_DYNAMIC_MULTICAST_DELEGATE_OneParam(FOnHealthChanged, float, NewHealth);

    UPROPERTY(BlueprintAssignable)
    FOnHealthChanged OnHealthChanged;

    virtual void GetLifetimeReplicatedProps(TArray<FLifetimeProperty>& OutLifetimeProps) const override;
};

Gameplay Ability System (GAS)

// Gameplay Ability
UCLASS()
class UGA_FireProjectile : public UGameplayAbility
{
    GENERATED_BODY()

public:
    UGA_FireProjectile();

    virtual void ActivateAbility(const FGameplayAbilitySpecHandle Handle,
        const FGameplayAbilityActorInfo* ActorInfo,
        const FGameplayAbilityActivationInfo ActivationInfo,
        const FGameplayEventData* TriggerEventData) override;

    virtual bool CanActivateAbility(const FGameplayAbilitySpecHandle Handle,
        const FGameplayAbilityActorInfo* ActorInfo,
        const FAbilityTagContainer* SourceTags,
        const FAbilityTagContainer* TargetTags,
        FGameplayTagContainer* OptionalRelevantTags) const override;

    UPROPERTY(EditDefaultsOnly, Category = "Projectile")
    TSubclassOf<AProjectile> ProjectileClass;

    UPROPERTY(EditDefaultsOnly, Category = "Cost")
    TSubclassOf<UGameplayEffect> CostEffect;
};

// Gameplay Effect for damage
UCLASS()
class UGE_Damage : public UGameplayEffect
{
    // Configured in Blueprint:
    // Duration: Instant
    // Modifiers: Attribute=Health, Op=Additive, Magnitude=-DamageAmount
    // Gameplay Cues: GC.Impact.Fire
};

// Attribute Set
UCLASS()
class UMyAttributeSet : public UAttributeSet
{
    GENERATED_BODY()

public:
    UPROPERTY(BlueprintReadOnly, ReplicatedUsing = OnRep_Health)
    FGameplayAttributeData Health;
    ATTRIBUTE_ACCESSORS(UMyAttributeSet, Health)

    UPROPERTY(BlueprintReadOnly, ReplicatedUsing = OnRep_Mana)
    FGameplayAttributeData Mana;
    ATTRIBUTE_ACCESSORS(UMyAttributeSet, Mana)

    virtual void PreAttributeChange(const FGameplayAttribute& Attribute, float& NewValue) override;
    virtual void PostGameplayEffectExecute(const FGameplayEffectModCallbackData& Data) override;
};