vault backup: 2024-05-17 18:03:12

03-UnrealEngine/Sequence/Sequence Runtime Binding.md

@@ -9,6 +9,11 @@ rating: ⭐
 参考：
 1. [sequencer mute tracks at runtime from c](https://forums.unrealengine.com/t/sequencer-mute-tracks-at-runtime-from-c/476278/3)
 
+可行思路：
+1. 给导播创建一个快捷键（Hotkey），之后在触发根据Tag切换对应角色动画蓝图中的逻辑。
+2. 使用Sequence的EventTrack设置若干事件。
+3. 模改UMovieSceneSkeletalAnimationTrack，实现一个可以自动根据Tag捕获对应角色并且播发动画的功能。
+
 # 方案一
 - UMovieSceneTrack::SetEvalDisabled(bool)
 - ULevelSequence::MarkAsChanged()
@@ -52,9 +57,11 @@ UMovieSceneSequenceExtensions methods are not exported. They don’t have the PL
 	- https://zhuanlan.zhihu.com/p/396353973
 	- https://zhuanlan.zhihu.com/p/414179358
 	- https://zhuanlan.zhihu.com/p/413151867
+- LevelSequence分析
+	- https://zhuanlan.zhihu.com/p/157892605
 
 ## 继承关系
-UMovieSceneSignedObject -> UObject
+UMovieSceneSignedObject -> UObject。一个UMovieScene由若干个MasterTrack(UMovieSceneTrack)组成，UMovieScene相当于是UMovieSceneTracks的容器，那么UMovieSceneTrack又由UMovieSceneSections组成，UMovieSceneSection就是一个Track中间的某一段。
 
 ### UMovieSceneSignedObject
 子类有UMovieScene、UMovieSceneSequence、UMovieSceneTrack、UMovieSceneSection。
@@ -74,5 +81,266 @@ UMovieSceneSignedObject -> UObject
 编辑器代码：**FSkeletalAnimationTrackEditor**
 
 ## Sequence绑定机制笔记
-
+1. _SpawnableObject_(自动Spawn的Object)  
+    表示该Object在Sequence被Evaluate的时候自动Spawn，并且由Sequence来管理生命周期
+2. _PossessableObject_(可以被赋予的Object)  
+    表示该Object可以被外部赋予，比如我手动赋予一个Actor给某个Track
 ### UMovieSceneSequence
+UMovieSceneSequence::CreatePossessable()
+UMovieSceneSequence::BindPossessableObject()
+
+绑定过程可以参考：
+ULevelSequenceEditorSubsystem::AddActorsToBinding(const TArray<AActor*>& Actors, const FMovieSceneBindingProxy& ObjectBinding)
+
+
+### ActorToSequencer
+菜单出现逻辑位于：FLevelSequenceEditorActorBinding::BuildSequencerAddMenu(FMenuBuilder& MenuBuilder)。
+
+`FLevelSequenceEditorActorBinding::AddPossessActorMenuExtensions(FMenuBuilder& MenuBuilder)`
+=>
+`FLevelSequenceEditorActorBinding::AddActorsToSequencer(AActor*const* InActors, int32 NumActors)`
+=>
+`TArray<FGuid> FSequencer::AddActors(const TArray<TWeakObjectPtr<AActor> >& InActors, bool bSelectActors)；`
+=>
+`TArray<FGuid> FSequencerUtilities::AddActors(TSharedRef<ISequencer> Sequencer, const TArray<TWeakObjectPtr<AActor> >& InActors)`
+
+```c++
+TArray<FGuid> FSequencerUtilities::AddActors(TSharedRef<ISequencer> Sequencer, const TArray<TWeakObjectPtr<AActor> >& InActors)
+{
+	TArray<FGuid> PossessableGuids;
+
+	UMovieSceneSequence* Sequence = Sequencer->GetFocusedMovieSceneSequence();
+	if (!Sequence)
+	{
+		return PossessableGuids;
+	}
+
+	UMovieScene* MovieScene = Sequence->GetMovieScene();
+	if (!MovieScene)
+	{
+		return PossessableGuids;
+	}
+
+	if (MovieScene->IsReadOnly())
+	{
+		ShowReadOnlyError();
+		return PossessableGuids;
+	}
+	
+	const FScopedTransaction Transaction(LOCTEXT("AddActors", "Add Actors"));
+	Sequence->Modify();
+
+	for (TWeakObjectPtr<AActor> WeakActor : InActors)
+	{
+		if (AActor* Actor = WeakActor.Get())
+		{
+			FGuid ExistingGuid = Sequencer->FindObjectId(*Actor, Sequencer->GetFocusedTemplateID());
+			if (!ExistingGuid.IsValid())
+			{
+				FGuid PossessableGuid = CreateBinding(Sequencer, *Actor, Actor->GetActorLabel());
+				PossessableGuids.Add(PossessableGuid);
+
+				if (ACameraActor* CameraActor = Cast<ACameraActor>(Actor))
+				{
+					NewCameraAdded(Sequencer, CameraActor, PossessableGuid);
+				}
+
+				Sequencer->OnActorAddedToSequencer().Broadcast(Actor, PossessableGuid);
+			}
+		}
+	}
+
+	return PossessableGuids;
+}
+```
+
+### FAudioTrackEditor
+FAudioTrackEditor::HandleAssetAdded(UObject* Asset, const FGuid& TargetObjectGuid) => FAudioTrackEditor::AddNewSound() => UMovieSceneAudioTrack::AddNewSoundOnRow(USoundBase* Sound, FFrameNumber Time, int32 RowIndex)
+
+## MovieSceneSkeletalAnimationTrack
+- UMovieSceneSkeletalAnimationTrack
+- UMovieSceneSkeletalAnimationSection
+- FSkeletalAnimationTrackEditor
+- UMovieSceneSkeletalAnimationSystem
+- FSkeletalAnimationTrackEditMode
+
+Track的编辑器注册位于MovieSceneToolsModule.cpp：
+```c++
+AnimationTrackCreateEditorHandle = SequencerModule.RegisterTrackEditor( FOnCreateTrackEditor::CreateStatic( &FSkeletalAnimationTrackEditor::CreateTrackEditor ) );
+```
+
+只对UMovieSceneSkeletalAnimationTrack生效：
+```c++
+bool FSkeletalAnimationTrackEditor::SupportsSequence(UMovieSceneSequence* InSequence) const  
+{  
+    ETrackSupport TrackSupported = InSequence ? InSequence->IsTrackSupported(UMovieSceneSkeletalAnimationTrack::StaticClass()) : ETrackSupport::NotSupported;  
+    return TrackSupported == ETrackSupport::Supported;  
+}
+
+FEditorModeRegistry::Get().RegisterMode<FSkeletalAnimationTrackEditMode>(  
+    FSkeletalAnimationTrackEditMode::ModeName,  
+    NSLOCTEXT("SkeletalAnimationTrackEditorMode", "SkelAnimTrackEditMode", "Skeletal Anim Track Mode"),  
+    FSlateIcon(),  
+    false);
+```
+
+### FSkeletalAnimationTrackEditor
+FSkeletalAnimationTrackEditor::BuildTrackContextMenu()：在MovieSceneSkeletalAnimationTrack的Animation上右键出现的菜单。
+FSkeletalAnimationTrackEditor::BuildOutlinerEditWidget：MovieSceneSkeletalAnimationTrack下面生成Animtion那一列。
+
+##  播放逻辑
+```c++
+ALevelSequenceActor::InitializePlayer() 
+ALevelSequenceActor->SequencePlayer->Play(); 
+ALevelSequenceActor->SequencePlayer->Update(DeltaSeconds);
+```
+
+具体的逻辑位于UMovieSceneSequencePlayer::PlayInternal()：
+```c++
+
+void UMovieSceneSequencePlayer::PlayInternal()
+{
+	if (NeedsQueueLatentAction())
+	{
+		QueueLatentAction(FMovieSceneSequenceLatentActionDelegate::CreateUObject(this, &UMovieSceneSequencePlayer::PlayInternal));
+		return;
+	}
+
+	if (!IsPlaying() && Sequence && CanPlay())
+	{
+		const FString SequenceName = GetSequenceName(true);
+		UE_LOG(LogMovieScene, Verbose, TEXT("PlayInternal - %s (current status: %s)"), *SequenceName, *UEnum::GetValueAsString(Status));
+
+		// Set playback status to playing before any calls to update the position
+		Status = EMovieScenePlayerStatus::Playing;
+
+		float PlayRate = bReversePlayback ? -PlaybackSettings.PlayRate : PlaybackSettings.PlayRate;
+
+		// If at the end and playing forwards, rewind to beginning
+		if (GetCurrentTime().Time == GetLastValidTime())
+		{
+			if (PlayRate > 0.f)
+			{
+				SetPlaybackPosition(FMovieSceneSequencePlaybackParams(FFrameTime(StartTime), EUpdatePositionMethod::Jump));
+			}
+		}
+		else if (GetCurrentTime().Time == FFrameTime(StartTime))
+		{
+			if (PlayRate < 0.f)
+			{
+				SetPlaybackPosition(FMovieSceneSequencePlaybackParams(GetLastValidTime(), EUpdatePositionMethod::Jump));
+			}
+		}
+
+		// Update now
+		if (PlaybackSettings.bRestoreState)
+		{
+			RootTemplateInstance.EnableGlobalPreAnimatedStateCapture();
+		}
+
+		bPendingOnStartedPlaying = true;
+		Status = EMovieScenePlayerStatus::Playing;
+		TimeController->StartPlaying(GetCurrentTime());
+		
+		if (PlayPosition.GetEvaluationType() == EMovieSceneEvaluationType::FrameLocked)
+		{
+			if (!OldMaxTickRate.IsSet())
+			{
+				OldMaxTickRate = GEngine->GetMaxFPS();
+			}
+
+			GEngine->SetMaxFPS(1.f / PlayPosition.GetInputRate().AsInterval());
+		}
+
+		//播放的核心逻辑估计在这里。
+		if (!PlayPosition.GetLastPlayEvalPostition().IsSet() || PlayPosition.GetLastPlayEvalPostition() != PlayPosition.GetCurrentPosition())
+		{
+			UpdateMovieSceneInstance(PlayPosition.PlayTo(PlayPosition.GetCurrentPosition()), EMovieScenePlayerStatus::Playing);
+		}
+
+		RunLatentActions();
+		UpdateNetworkSyncProperties();
+		
+		if (bReversePlayback)
+		{
+			if (OnPlayReverse.IsBound())
+			{
+				OnPlayReverse.Broadcast();
+			}
+		}
+		else
+		{
+			if (OnPlay.IsBound())
+			{
+				OnPlay.Broadcast();
+			}
+		}
+	}
+}
+
+void UMovieSceneSequencePlayer::UpdateMovieSceneInstance(FMovieSceneEvaluationRange InRange, EMovieScenePlayerStatus::Type PlayerStatus, bool bHasJumped)
+{
+	FMovieSceneUpdateArgs Args;
+	Args.bHasJumped = bHasJumped;
+	UpdateMovieSceneInstance(InRange, PlayerStatus, Args);
+}
+
+void UMovieSceneSequencePlayer::UpdateMovieSceneInstance(FMovieSceneEvaluationRange InRange, EMovieScenePlayerStatus::Type PlayerStatus, const FMovieSceneUpdateArgs& Args)
+{
+	if (Observer && !Observer->CanObserveSequence())
+	{
+		return;
+	}
+
+	UMovieSceneSequence* MovieSceneSequence = RootTemplateInstance.GetSequence(MovieSceneSequenceID::Root);
+	if (!MovieSceneSequence)
+	{
+		return;
+	}
+
+#if !NO_LOGGING
+	if (UE_LOG_ACTIVE(LogMovieScene, VeryVerbose))
+	{
+		const FQualifiedFrameTime CurrentTime = GetCurrentTime();
+		const FString SequenceName = GetSequenceName(true);
+		UE_LOG(LogMovieScene, VeryVerbose, TEXT("Evaluating sequence %s at frame %d, subframe %f (%f fps)."), *SequenceName, CurrentTime.Time.FrameNumber.Value, CurrentTime.Time.GetSubFrame(), CurrentTime.Rate.AsDecimal());
+	}
+#endif
+
+	if (PlaybackClient)
+	{
+		PlaybackClient->WarpEvaluationRange(InRange);
+	}
+
+	// Once we have updated we must no longer skip updates
+	bSkipNextUpdate = false;
+
+	// We shouldn't be asked to run an async update if we have a blocking sequence.
+	check(!Args.bIsAsync || !EnumHasAnyFlags(MovieSceneSequence->GetFlags(), EMovieSceneSequenceFlags::BlockingEvaluation));
+	// We shouldn't be asked to run an async update if we don't have a tick manager.
+	check(!Args.bIsAsync || TickManager != nullptr);
+
+	FMovieSceneContext Context(InRange, PlayerStatus);
+	Context.SetHasJumped(Args.bHasJumped);
+
+	TSharedPtr<FMovieSceneEntitySystemRunner> Runner = RootTemplateInstance.GetRunner();
+	if (Runner)
+	{
+		Runner->QueueUpdate(Context, RootTemplateInstance.GetRootInstanceHandle());
+		if (Runner == SynchronousRunner || !Args.bIsAsync)
+		{
+			Runner->Flush();
+		}
+	}
+}
+```
+
+暂停的核心逻辑：
+```c++
+FMovieSceneEvaluationRange CurrentTimeRange = PlayPosition.GetCurrentPositionAsRange();
+const FMovieSceneContext Context(CurrentTimeRange, EMovieScenePlayerStatus::Stopped);
+Runner->QueueUpdate(Context, RootTemplateInstance.GetRootInstanceHandle(), FSimpleDelegate::CreateWeakLambda(this, FinishPause));
+```
+
+## SequenceRecorder
+SequenceRecorder模块的基类是ISequenceRecorder。