UExperimentDemoSubsystem¶

Game instance subsystem that manages demo recording, playback, and replay enumeration.

Syntax¶

class UExperimentDemoSubsystem : public UGameInstanceSubsystem

Remarks¶

Adapted from the driving simulator so that any project can use this functionality without replacing its own game instance class. Attach to any UGameInstance by including the plugin. Provides Blueprint-callable wrappers for all core replay operations, a demo-rendering pipeline for offline frame capture, and OBS integration stubs. UCLASS

Inheritance Hierarchy¶

UGameInstanceSubsystem → UExperimentDemoSubsystem

Methods¶

Method	Signature	Description	Blueprint
BP_OnFindReplaysComplete	`void UExperimentDemoSubsystem::BP_OnFindReplaysComplete(const TArray< FReplayInfo > &AllReplays)`	Blueprint event fired when replay enumeration completes.	yes
CaptureFrames	`bool UExperimentDemoSubsystem::CaptureFrames() const`	Returns whether the spectator controller should capture frames during playback.
Deinitialize	`void UExperimentDemoSubsystem::Deinitialize() override`	Called by Unreal when the subsystem is destroyed.
DeleteReplay	`void UExperimentDemoSubsystem::DeleteReplay(const FString &ReplayName)`	Deletes an existing replay from disk.	yes
DemoRenderFrames	`void UExperimentDemoSubsystem::DemoRenderFrames(const FString &demoName, int fps)`	Plays back a demo and renders each frame to disk using a spectator controller.	yes
FindReplays	`void UExperimentDemoSubsystem::FindReplays()`	Asynchronously enumerates all available demo files.	yes
GetCaptureFPS	`int UExperimentDemoSubsystem::GetCaptureFPS() const`	Returns the target frame rate for demo rendering.
GetCaptureFolder	`FString * UExperimentDemoSubsystem::GetCaptureFolder() const`	Returns folder path where captured frames are saved.
GetDemoName	`FString * UExperimentDemoSubsystem::GetDemoName() const`	Returns the filename of the demo currently being rendered.
GetDemoState	`int UExperimentDemoSubsystem::GetDemoState() const`	Returns the current demo recording status code.
GetDemosList	`const TArray< FString > & UExperimentDemoSubsystem::GetDemosList()`	Returns the list of demo filenames, enumerated from disk on every call.	yes
GetExperimentType	`EExperimentType UExperimentDemoSubsystem::GetExperimentType() const`	Returns the current experiment type loaded from settings.
GetIsDemoRenderedList	`const TArray< bool > & UExperimentDemoSubsystem::GetIsDemoRenderedList()`	Returns a bool array indicating which demos have already been rendered.	yes
GetPlayerPawn	`APawn * UExperimentDemoSubsystem::GetPlayerPawn()`	Returns the player pawn, using tag-based lookup or name-based lookup as appropriate.
GetPlayerPawnByName	`APawn * UExperimentDemoSubsystem::GetPlayerPawnByName()`	Finds the player pawn by searching for an actor whose name matches the stored player pawn name.
GetPlayerPawnByTag	`APawn * UExperimentDemoSubsystem::GetPlayerPawnByTag()`	Finds the player pawn by searching for an actor tagged with ExperimentPlayerTag.
Initialize	`void UExperimentDemoSubsystem::Initialize(FSubsystemCollectionBase &Collection) override`	Called by Unreal when the subsystem is created.
IsAutoRender	`bool UExperimentDemoSubsystem::IsAutoRender() const`	Whether we should automatically render all demos.
IsPlayingReplay	`bool UExperimentDemoSubsystem::IsPlayingReplay()`	Returns whether a replay is currently being played back.
IsRecordingReplay	`bool UExperimentDemoSubsystem::IsRecordingReplay()`	Returns whether a replay is currently being recorded.	yes
OnReplayEnded	`void UExperimentDemoSubsystem::OnReplayEnded()`	Marks replay playback as ended and returns all replay and recording state to its initial values, so the reloaded gameplay world starts clean: a later watched replay does not re-enter the frame-capture path, auto demo recording can trigger again, and pawn lookups do not go through the dead replay pawn's cached name.
PlayReplay	`void UExperimentDemoSubsystem::PlayReplay(const FString &replayName)`	Plays the demo with the given name.
PlayReplayFromBP	`void UExperimentDemoSubsystem::PlayReplayFromBP(FString ReplayName)`	Blueprint-callable wrapper to begin playing back a demo.	yes
ReadSettings	`void UExperimentDemoSubsystem::ReadSettings(UExperimentSettings *settings)`	Reads relevant settings from the settings object.
RenameReplay	`void UExperimentDemoSubsystem::RenameReplay(const FString &ReplayName, const FString &NewFriendlyReplayName)`	Renames an existing replay.	yes
RequestOBSRecording	`int UExperimentDemoSubsystem::RequestOBSRecording(bool startStop)`	Requests OBS to start or stop recording.
SetCaptureFolder	`void UExperimentDemoSubsystem::SetCaptureFolder(const FString &folder)`	Sets the folder where rendered frames will be saved.
StartRecordingReplay	`void UExperimentDemoSubsystem::StartRecordingReplay(const FString &name, const FString &friendlyName)`	Begins recording a new demo.
StartRecordingReplayFromBP	`void UExperimentDemoSubsystem::StartRecordingReplayFromBP(FString ReplayName, FString FriendlyName)`	Blueprint-callable wrapper to begin recording a demo.	yes
StopRecordingReplay	`void UExperimentDemoSubsystem::StopRecordingReplay()`	Stops the currently active demo recording.
StopRecordingReplayFromBP	`void UExperimentDemoSubsystem::StopRecordingReplayFromBP()`	Blueprint-callable wrapper to stop the currently active demo recording.	yes

Properties¶

Property	Type	Description	Blueprint
demoStartTime	`FDateTime`	Timestamp recording when the current demo recording started.
replayToRender	`FString`	Name of the next replay to render when auto-rendering is enabled.	yes