DoOnce

Lets execution through once, then blocks subsequent attempts until Reset is called. Useful for one-shot triggers.

RetriggerableDelay — delay that resets if triggered again

UKismetSystemLibrary::RetriggerableDelay. Latent.

RestartPlayer — respawn a player at a PlayerStart

Call on GameMode. The controller's StartSpot or nearest PlayerStart is used.

Level transition: save data then open new level

Pattern: custom trigger or UI button → [save player data to SaveSlot] → OpenLevel(LevelName='Level_02', bAbsolute=true, Options=''). For loading screen: SetGlobalTimeDilation(0.001) briefly while level loads (freeze world), or use AsyncLoadLevel with progress callback. Key: OpenLevel is in GameplayStatics. 'LevelName' is the map asset name (not full path). bAbsolute=true discards current level completely. Options string can pass params like '?GameMode=BP_GM'.

Health regeneration over time with timer

Pattern: Variables RegenRate(float)=5.0, RegenDelay(float)=3.0, RegenTimerHandle. On damage received: ClearTimer(RegenTimerHandle) → SET timer(RegenDelay, RegenTick, looping=true). RegenTick function: Branch(Health < MaxHealth) → True: SET Health = FClamp(Health + RegenRate*DeltaSeconds, 0, MaxHealth). False: ClearTimer.

ClearAndInvalidateTimerByHandle — stop and clear a timer

K2_ClearAndInvalidateTimerHandle.

SetGamePaused — pause or unpause the game

UGameplayStatics::SetGamePaused.

Array Clear — remove all elements from array

DoN — execute N times then stop

Respawn system: death → delay → respawn at PlayerStart

In Character BP: OnDied (custom event) → SetActorHiddenInGame(true) → SetActorEnableCollision(false) → Disable input: GetController → DisableInput → Delay(Duration=3.0) → GetGameMode → CastTo<BP_GameMode> → RestartPlayer(GetController) → SetActorHiddenInGame(false) → SetActorEnableCollision(true) → EnableInput. In GameMode RestartPlayer: Gets nearest PlayerStart → SetActorLocation to PlayerStart → calls OnPossess. OR manual: GetAllActorsOfClass(PlayerStart) → Random select → SetActorLocationAndRotation(PlayerStart.Location, PlayerStart.Rotation).