State Machine

A graph of animation states connected by transitions. Each state plays a sequence/blend; transitions fire on rule conditions.

State machine pattern using enum variable and switch

Variables: CurrentState (your EState enum: Idle, Patrol, Chase, Attack, Dead). EventTick or custom Update event → Switch on EState(CurrentState) → Idle: [idle logic] → Patrol: [patrol logic] → Chase: [chase logic] etc. State transitions via custom events: OnEnemySpotted → SetVariable(CurrentState=EState::Chase). OnEnemyLost → SetVariable(CurrentState=EState::Patrol). OnDamaged → Branch(Health<=0) → True: SetVariable(CurrentState=EState::Dead). Key: Switch On Enum node — connect enum variable to the input, each value gets an exec output pin.

Animation Blueprint

An AnimBP — drives Skeletal Mesh animation via a state machine + transition rules. Set AnimClass on the Skeletal Mesh Component.

Gate — pass or block execution based on open/closed state

Game subsystem: persistent game manager with auto-init

SETUP: Create Blueprint inheriting UGameInstanceSubsystem (or UWorldSubsystem for level-scoped). Override Initialize(Collection) to set up. Override Deinitialize to clean up. Add game variables here (Score, PlayTime, Settings). ACCESS FROM ANYWHERE: GetGameInstance → GetSubsystem(BP_GameSubsystem) → CastTo<BP_GameSubsystem> → access variables. WHY: Subsystems auto-create, auto-destroy, and don't need FindActor. Better than GameInstance for well-organized systems. UGameInstanceSubsystem persists across levels. UWorldSubsystem is recreated each level.

EnhancedInputAction — Enhanced Input system action event

K2Node_EnhancedInputAction. ActionValue type depends on InputAction (Bool, Float, Axis2D, Axis3D). Triggers: Started, Ongoing, Triggered, Completed, Canceled.

GetGameState — get current game state

Possess — make a Controller possess a Pawn

Enhanced Input system setup with Input Actions and Mapping Context

Setup: Create InputAction assets (IA_Move Axis2D, IA_Jump Digital). Create InputMappingContext (IMC_Default) mapping keys to IAs. BeginPlay: GetPlayerController → GetEnhancedInputLocalPlayerSubsystem → AddMappingContext(IMC_Default, 0). Bind: EnhancedInputAction IA_Move → Triggered pin → ActionValue → BreakVector2D → AddMovementInput.

Health and damage system with ApplyDamage and EventAnyDamage

Dealing damage: Event → ApplyDamage(TargetActor, BaseDamage, InstigatorController, DamageCauser, DamageTypeClass). Receiving: EventAnyDamage → Damage output → Subtract_FloatFloat(CurrentHealth, Damage) → FClamp(Result, 0, MaxHealth) → SET CurrentHealth → Branch(CurrentHealth <= 0) → True: DestroyActor. Initialize CurrentHealth=MaxHealth in BeginPlay.