BP_Checkpoint — Checkpoint Actor

File: Content/Framework/Save/BP_Checkpoint

Purpose: Manages checkpoint volumes in the world, tracks the most recent checkpoint crossed by the player, and triggers save operations via SS_SaveManager. Also stores respawn transform data for use by the death handling systems.

Depends On: SS_SaveManager, GM_CoreGameMode Used By: Player Controller or Game Mode (placed at game setup)

Enums

// E_CheckpointActivationMode — Determines when a checkpoint triggers
E_CheckpointActivationMode
{
  OnOverlap,     // Player overlaps the checkpoint volume
  OnInteract,    // Player must press an interact key at the checkpoint
  Automated      // Triggered by external event (e.g., completing a puzzle)
}

Structs

// S_CheckpointData — Runtime data for one checkpoint
S_CheckpointData
{
  CheckpointTag:      GameplayTag   // Unique identifier for this checkpoint
  DisplayName:        FText         // "Save Room - Floor 2", etc.
  RespawnLocation:    Transform     // Where the player spawns on reload
  CameraCutTransform: Transform     // Optional camera cut point for respawn transition
  bHasBeenUsed:       Bool          // Has the player crossed this checkpoint?
  ActivationMode:     E_CheckpointActivationMode
  bAutoSave:          Bool          // Does crossing this checkpoint trigger an auto-save?
  LinkedObjectives:   Array of GameplayTag  // Objectives to mark complete on activation
}

// S_RespawnCache — Lightweight in-memory respawn data (not saved to disk)
S_RespawnCache
{
  LastCheckpointTag:      GameplayTag
  LastCheckpointLocation: Transform
  bIsRespawnFromDeath:    Bool      // False = checkpoint load, True = death respawn
  DeathCountAtCheckpoint: Integer   // Snapshot of death count for metrics
}

Variables

Name	Type	Description
`RegisteredCheckpoints`	Map (GameplayTag → `S_CheckpointData`)	All checkpoint volumes in the current level
`ActiveCheckpoint`	`S_CheckpointData`	The most recently activated checkpoint
`RespawnCache`	`S_RespawnCache`	Lightweight cache for respawn without full load
`bCanCrossCheckpoint`	Bool	Cooldown guard to prevent double-trigger (reset after 0.5s)
`DefaultRespawnTransform`	Transform	Fallback spawn point if no checkpoint exists (level start)
`CheckpointCooldownTimer`	Float	Timer handle for cooldown (0.5s default)

Functions / Events

Name	Inputs	Outputs	Description
`RegisterCheckpoint`	Data: `S_CheckpointData`	—	Adds a checkpoint to the registered map
`UnregisterCheckpoint`	CheckpointTag: GameplayTag	—	Removes a checkpoint from the map
`ActivateCheckpoint`	CheckpointTag: GameplayTag	—	Sets the given checkpoint as active; triggers save if `bAutoSave` is true
`GetActiveCheckpoint`	—	`S_CheckpointData`	Returns the currently active checkpoint
`GetRespawnTransform`	—	Transform	Returns the respawn location (active checkpoint or fallback)
`HasActiveCheckpoint`	—	Bool	Returns whether a checkpoint has been crossed
`GetCheckpointList`	—	Array of `S_CheckpointData`	Returns all registered checkpoints (for UI map / fast travel)
`ClearCheckpointData`	—	—	Resets all checkpoint state (on new game)
`SetDefaultRespawn`	Transform: Transform	—	Sets the fallback respawn point when no checkpoint exists
`OnPlayerDeath`	—	—	Fired by GM_CoreGameMode; caches current checkpoint as death respawn point
`OnPlayerRespawn`	—	—	Fired after respawn; clears death flags

Event Dispatchers

Name	Parameters	Fired When
`OnCheckpointActivated`	CheckpointTag: GameplayTag, DisplayName: FText	A checkpoint is crossed and becomes active
`OnCheckpointSaveTriggered`	CheckpointTag: GameplayTag	An auto-save was triggered by this checkpoint
`OnRespawnPointSet`	RespawnTransform: Transform	The respawn point has changed
`OnCheckpointListChanged`	CheckpointCount: Int	A checkpoint was added or removed

Blueprint Flow Diagram

flowchart TD
    A[Player overlaps checkpoint volume] --> B{Volume implements\nI_CheckpointVolume?}
    B -->|No| C[Ignore]
    B -->|Yes| D[Get checkpoint GameplayTag]
    D --> E{Can cross?\nbCanCrossCheckpoint}
    E -->|No| F[Ignore]
    E -->|Yes| G[Set bCanCrossCheckpoint = false]
    G --> H[Lookup in RegisteredCheckpoints map]
    H --> I{Found?}
    I -->|No| J[Log warning: unregistered checkpoint]
    I -->|Yes| K[Set ActiveCheckpoint = found data]
    K --> L[Set RespawnCache.LastCheckpointTag]
    L --> M[Set RespawnCache.LastCheckpointLocation]
    M --> N[Broadcast OnCheckpointActivated]
    N --> O{bAutoSave?}
    O -->|Yes| P[SS_SaveManager.SaveCheckpoint\nCheckpointTag]
    P --> Q[Broadcast OnCheckpointSaveTriggered]
    O -->|No| R[Skip save]
    R --> S[Start cooldown timer 0.5s]
    Q --> S
    S --> T[Timer expires -> set bCanCrossCheckpoint = true]

Communication Matrix

Target System	Method	Why
`SS_SaveManager`	Direct call `SaveCheckpoint`	Trigger checkpoint auto-save
`SS_SaveManager`	Bind to `OnLoadComplete`	Restore active checkpoint tag after load
`GM_CoreGameMode`	Bind to death/respawn events	Receive death and respawn notifications
`BPC_PlayerRespawnSystem`	Provide `GetRespawnTransform`	Supply respawn location on death
`BPC_DeathHandlingSystem`	Provide `RespawnCache` data	Death handling reads cache for appropriate flow
Checkpoint Volume Actors	Interface call	Register/unregister via BeginPlay/EndPlay
`WBP_CheckpointNotification`	Dispatcher `OnCheckpointActivated`	Show "Checkpoint Saved" HUD notification
`WBP_MapWidget`	Function `GetCheckpointList`	Display discovered checkpoints on map

Checkpoint Volume Setup

BP_CheckpointVolume (Box Collision, Render CustomDepth)
  └── Collision: OverlapOnly (PlayerOnly)
  └── OnComponentBeginOverlap
       └── Get owner's CheckpointTag (GameplayTag)
       └── Call BP_Checkpoint.ActivateCheckpoint(Tag)

Checkpoint Volume Variables:

Variable	Type	Source
`CheckpointTag`	GameplayTag	Set per-instance in level
`DisplayName`	FText	Set in defaults (e.g., "Hospital Lobby")
`RespawnLocation`	Transform	Arrow component on the volume
`CameraCutTransform`	Transform	Optional arrow component
`ActivationMode`	E_CheckpointActivationMode	Overlap by default
`bAutoSave`	Bool	True by default

Reuse Notes

Each checkpoint volume creates itself by calling RegisterCheckpoint in BeginPlay with its configured S_CheckpointData
Single-player only — multiplayer requires a server-authorised version with per-player checkpoint tracking
The 0.5s cooldown prevents double-activation from overlapping two volumes simultaneously
DefaultRespawnTransform should be set by GM_CoreGameMode on level start from the PlayerStart actor
CheckpointTag naming convention: Checkpoint.<LevelName>.<AreaName>
Renamed from BPC_CheckpointSystem to BP_Checkpoint per Master naming convention.

7.4 KiB Raw Blame History