475 lines
18 KiB
Markdown
475 lines
18 KiB
Markdown
---
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title: Sequence Runtime Binding
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date: 2024-05-16 17:55:58
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excerpt:
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tags:
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rating: ⭐
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---
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# 前言
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***MovieSceneTextTrack*** 引擎插件可以作为参考。
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***UMovieSceneCVarTrackInstance***
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参考：
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1. [sequencer mute tracks at runtime from c](https://forums.unrealengine.com/t/sequencer-mute-tracks-at-runtime-from-c/476278/3)
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2. 其他参考
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1. [Actor Rebinding in Blueprints with Sequencer(官方文档)]https://docs.unrealengine.com/4.27/en-US/AnimatingObjects/Sequencer/HowTo/AnimateDynamicObjects/
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2. [Level Sequence actor rebinding in C++](https://www.reddit.com/r/unrealengine/comments/btk1uz/level_sequence_actor_rebinding_in_c/)
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3. Sequence ECS资料
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1. [大规模内容的性能保障：虚幻引擎4.26中的Sequencer(官方文档)](https://www.unrealengine.com/zh-CN/tech-blog/performance-at-scale-sequencer-in-unreal-engine-4-26)
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2. [UE4.26(5.0)后的Sequence系统](https://zhuanlan.zhihu.com/p/589465561)
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3. [UE5 Sequence 浅-浅-析](https://zhuanlan.zhihu.com/p/676690043)
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4. ECS资料
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1. [一文看懂ECS架构]https://zhuanlan.zhihu.com/p/618971664
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可行思路：
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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。
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2. [x] 使用Sequence的EventTrack设置若干事件。
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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。
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# 自定义Track
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- Runtime修改绑定
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- UE4：扩展Sequencer的BakeTransform有关Camera的参数:https://zhuanlan.zhihu.com/p/554484287
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- **LevelSequence对象绑定分析**:https://zhuanlan.zhihu.com/p/548155341
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- 自定义Track
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- https://zhuanlan.zhihu.com/p/396353973
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- https://zhuanlan.zhihu.com/p/414179358
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- https://zhuanlan.zhihu.com/p/413151867
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- LevelSequence分析
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- https://zhuanlan.zhihu.com/p/157892605
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## UMovieSceneTrackInstance
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大部分Track的instance类。
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## 继承关系
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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。
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### UMovieSceneSignedObject
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子类有UMovieScene、UMovieSceneSequence、UMovieSceneTrack、UMovieSceneSection。
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定义：
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- FGuid Signature：用于确定Object身份，以便于绑定。
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- FOnSignatureChanged OnSignatureChangedEvent：ChangedEvent。
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### UMovieSceneSection
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#### UMovieSceneSkeletalAnimationSection
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### UMovieSceneTrack
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#### UMovieSceneSkeletalAnimationTrack
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- `TArray<TObjectPtr<UMovieSceneSection>> AnimationSections`：存储所有动画Section。
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- FMovieSceneSkeletalAnimRootMotionTrackParams RootMotionParams：RootMotion控制。
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编辑器代码：**FSkeletalAnimationTrackEditor**
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## Sequence绑定机制笔记
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1. _SpawnableObject_(自动Spawn的Object)
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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
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2. _PossessableObject_(可以被赋予的Object)
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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
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### UMovieSceneSequence
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UMovieSceneSequence::CreatePossessable()
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UMovieSceneSequence::BindPossessableObject()
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绑定过程可以参考：
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ULevelSequenceEditorSubsystem::AddActorsToBinding(const TArray<AActor*>& Actors, const FMovieSceneBindingProxy& ObjectBinding)
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### ActorToSequencer
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菜单出现逻辑位于：FLevelSequenceEditorActorBinding::BuildSequencerAddMenu(FMenuBuilder& MenuBuilder)。
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`FLevelSequenceEditorActorBinding::AddPossessActorMenuExtensions(FMenuBuilder& MenuBuilder)`
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=>
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`FLevelSequenceEditorActorBinding::AddActorsToSequencer(AActor*const* InActors, int32 NumActors)`
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=>
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`TArray<FGuid> FSequencer::AddActors(const TArray<TWeakObjectPtr<AActor> >& InActors, bool bSelectActors)；`
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=>
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`TArray<FGuid> FSequencerUtilities::AddActors(TSharedRef<ISequencer> Sequencer, const TArray<TWeakObjectPtr<AActor> >& InActors)`
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```c++
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TArray<FGuid> FSequencerUtilities::AddActors(TSharedRef<ISequencer> Sequencer, const TArray<TWeakObjectPtr<AActor> >& InActors)
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{
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TArray<FGuid> PossessableGuids;
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UMovieSceneSequence* Sequence = Sequencer->GetFocusedMovieSceneSequence();
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if (!Sequence)
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{
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return PossessableGuids;
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}
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UMovieScene* MovieScene = Sequence->GetMovieScene();
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if (!MovieScene)
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{
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return PossessableGuids;
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}
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if (MovieScene->IsReadOnly())
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{
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ShowReadOnlyError();
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return PossessableGuids;
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}
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const FScopedTransaction Transaction(LOCTEXT("AddActors", "Add Actors"));
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Sequence->Modify();
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for (TWeakObjectPtr<AActor> WeakActor : InActors)
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{
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if (AActor* Actor = WeakActor.Get())
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{
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FGuid ExistingGuid = Sequencer->FindObjectId(*Actor, Sequencer->GetFocusedTemplateID());
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if (!ExistingGuid.IsValid())
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{
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FGuid PossessableGuid = CreateBinding(Sequencer, *Actor, Actor->GetActorLabel());
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PossessableGuids.Add(PossessableGuid);
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if (ACameraActor* CameraActor = Cast<ACameraActor>(Actor))
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{
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NewCameraAdded(Sequencer, CameraActor, PossessableGuid);
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}
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Sequencer->OnActorAddedToSequencer().Broadcast(Actor, PossessableGuid);
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}
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}
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}
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return PossessableGuids;
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}
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```
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其他参考
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```c++
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const FGuid PossessableGuid = OwnerMovieScene->AddPossessable(InName, InObject.GetClass());
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if (!OwnerMovieScene->FindPossessable(PossessableGuid)->BindSpawnableObject(Sequencer->GetFocusedTemplateID(), &InObject, &Sequencer.Get()))
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{
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OwnerSequence->BindPossessableObject(PossessableGuid, InObject, BindingContext);
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}
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```
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```c++
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FGuid FSequencerUtilities::CreateBinding(TSharedRef<ISequencer> Sequencer, UObject& InObject, const FString& InName)
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{
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const FScopedTransaction Transaction(LOCTEXT("CreateBinding", "Create New Binding"));
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UMovieSceneSequence* OwnerSequence = Sequencer->GetFocusedMovieSceneSequence();
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UMovieScene* OwnerMovieScene = OwnerSequence->GetMovieScene();
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OwnerSequence->Modify();
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OwnerMovieScene->Modify();
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const FGuid PossessableGuid = OwnerMovieScene->AddPossessable(InName, InObject.GetClass());
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// Attempt to use the parent as a context if necessary
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UObject* ParentObject = OwnerSequence->GetParentObject(&InObject);
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UObject* BindingContext = Sequencer->GetPlaybackContext();
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AActor* ParentActorAdded = nullptr;
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FGuid ParentGuid;
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if (ParentObject)
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{
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// Ensure we have possessed the outer object, if necessary
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ParentGuid = Sequencer->GetHandleToObject(ParentObject, false);
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if (!ParentGuid.IsValid())
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{
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ParentGuid = Sequencer->GetHandleToObject(ParentObject);
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ParentActorAdded = Cast<AActor>(ParentObject);
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}
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if (OwnerSequence->AreParentContextsSignificant())
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{
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BindingContext = ParentObject;
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}
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// Set up parent/child guids for possessables within spawnables
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if (ParentGuid.IsValid())
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{
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FMovieScenePossessable* ChildPossessable = OwnerMovieScene->FindPossessable(PossessableGuid);
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if (ensure(ChildPossessable))
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{
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ChildPossessable->SetParent(ParentGuid, OwnerMovieScene);
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}
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FMovieSceneSpawnable* ParentSpawnable = OwnerMovieScene->FindSpawnable(ParentGuid);
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if (ParentSpawnable)
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{
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ParentSpawnable->AddChildPossessable(PossessableGuid);
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}
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}
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}
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if (!OwnerMovieScene->FindPossessable(PossessableGuid)->BindSpawnableObject(Sequencer->GetFocusedTemplateID(), &InObject, &Sequencer.Get()))
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{
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OwnerSequence->BindPossessableObject(PossessableGuid, InObject, BindingContext);
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}
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// Broadcast if a parent actor was added as a result of adding this object
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if (ParentActorAdded && ParentGuid.IsValid())
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{
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Sequencer->OnActorAddedToSequencer().Broadcast(ParentActorAdded, ParentGuid);
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}
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return PossessableGuid;
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}
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```
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### FAudioTrackEditor
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FAudioTrackEditor::HandleAssetAdded(UObject* Asset, const FGuid& TargetObjectGuid) => FAudioTrackEditor::AddNewSound() => UMovieSceneAudioTrack::AddNewSoundOnRow(USoundBase* Sound, FFrameNumber Time, int32 RowIndex)
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## MovieSceneSkeletalAnimationTrack
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- UMovieSceneSkeletalAnimationTrack
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- UMovieSceneSkeletalAnimationSection
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- FMovieSceneSkeletalAnimationParams
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- `TObjectPtr<UAnimSequenceBase> Animation`
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- FSkeletalAnimationTrackEditor
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- UMovieSceneSkeletalAnimationSystem
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- 里面有介绍System相关的逻辑 https://zhuanlan.zhihu.com/p/413151867
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- FSkeletalAnimationTrackEditMode
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Track的编辑器注册位于MovieSceneToolsModule.cpp：
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```c++
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AnimationTrackCreateEditorHandle = SequencerModule.RegisterTrackEditor( FOnCreateTrackEditor::CreateStatic( &FSkeletalAnimationTrackEditor::CreateTrackEditor ) );
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```
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只对UMovieSceneSkeletalAnimationTrack生效：
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```c++
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bool FSkeletalAnimationTrackEditor::SupportsSequence(UMovieSceneSequence* InSequence) const
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{
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ETrackSupport TrackSupported = InSequence ? InSequence->IsTrackSupported(UMovieSceneSkeletalAnimationTrack::StaticClass()) : ETrackSupport::NotSupported;
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return TrackSupported == ETrackSupport::Supported;
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}
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FEditorModeRegistry::Get().RegisterMode<FSkeletalAnimationTrackEditMode>(
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FSkeletalAnimationTrackEditMode::ModeName,
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NSLOCTEXT("SkeletalAnimationTrackEditorMode", "SkelAnimTrackEditMode", "Skeletal Anim Track Mode"),
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FSlateIcon(),
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false);
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```
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### FSkeletalAnimationTrackEditor
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FSkeletalAnimationTrackEditor::BuildTrackContextMenu()：在MovieSceneSkeletalAnimationTrack的Animation上右键出现的菜单。
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FSkeletalAnimationTrackEditor::BuildOutlinerEditWidget：MovieSceneSkeletalAnimationTrack下面生成Animtion那一列。
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## 播放逻辑
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```c++
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ALevelSequenceActor::InitializePlayer()
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ALevelSequenceActor->SequencePlayer->Play();
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ALevelSequenceActor->SequencePlayer->Update(DeltaSeconds);
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```
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具体的逻辑位于UMovieSceneSequencePlayer::PlayInternal()：
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```c++
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void UMovieSceneSequencePlayer::PlayInternal()
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{
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if (NeedsQueueLatentAction())
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{
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QueueLatentAction(FMovieSceneSequenceLatentActionDelegate::CreateUObject(this, &UMovieSceneSequencePlayer::PlayInternal));
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return;
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}
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if (!IsPlaying() && Sequence && CanPlay())
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{
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const FString SequenceName = GetSequenceName(true);
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UE_LOG(LogMovieScene, Verbose, TEXT("PlayInternal - %s (current status: %s)"), *SequenceName, *UEnum::GetValueAsString(Status));
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// Set playback status to playing before any calls to update the position
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Status = EMovieScenePlayerStatus::Playing;
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float PlayRate = bReversePlayback ? -PlaybackSettings.PlayRate : PlaybackSettings.PlayRate;
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// If at the end and playing forwards, rewind to beginning
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if (GetCurrentTime().Time == GetLastValidTime())
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{
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if (PlayRate > 0.f)
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{
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SetPlaybackPosition(FMovieSceneSequencePlaybackParams(FFrameTime(StartTime), EUpdatePositionMethod::Jump));
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}
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}
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else if (GetCurrentTime().Time == FFrameTime(StartTime))
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{
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if (PlayRate < 0.f)
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{
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SetPlaybackPosition(FMovieSceneSequencePlaybackParams(GetLastValidTime(), EUpdatePositionMethod::Jump));
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}
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}
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// Update now
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if (PlaybackSettings.bRestoreState)
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{
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RootTemplateInstance.EnableGlobalPreAnimatedStateCapture();
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}
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bPendingOnStartedPlaying = true;
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Status = EMovieScenePlayerStatus::Playing;
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TimeController->StartPlaying(GetCurrentTime());
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if (PlayPosition.GetEvaluationType() == EMovieSceneEvaluationType::FrameLocked)
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{
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if (!OldMaxTickRate.IsSet())
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{
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OldMaxTickRate = GEngine->GetMaxFPS();
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}
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GEngine->SetMaxFPS(1.f / PlayPosition.GetInputRate().AsInterval());
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}
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//播放的核心逻辑估计在这里。
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if (!PlayPosition.GetLastPlayEvalPostition().IsSet() || PlayPosition.GetLastPlayEvalPostition() != PlayPosition.GetCurrentPosition())
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{
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UpdateMovieSceneInstance(PlayPosition.PlayTo(PlayPosition.GetCurrentPosition()), EMovieScenePlayerStatus::Playing);
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}
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RunLatentActions();
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UpdateNetworkSyncProperties();
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if (bReversePlayback)
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{
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if (OnPlayReverse.IsBound())
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{
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OnPlayReverse.Broadcast();
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}
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}
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else
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{
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if (OnPlay.IsBound())
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{
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OnPlay.Broadcast();
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}
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}
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}
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}
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void UMovieSceneSequencePlayer::UpdateMovieSceneInstance(FMovieSceneEvaluationRange InRange, EMovieScenePlayerStatus::Type PlayerStatus, bool bHasJumped)
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{
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FMovieSceneUpdateArgs Args;
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Args.bHasJumped = bHasJumped;
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UpdateMovieSceneInstance(InRange, PlayerStatus, Args);
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}
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void UMovieSceneSequencePlayer::UpdateMovieSceneInstance(FMovieSceneEvaluationRange InRange, EMovieScenePlayerStatus::Type PlayerStatus, const FMovieSceneUpdateArgs& Args)
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{
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if (Observer && !Observer->CanObserveSequence())
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{
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return;
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}
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UMovieSceneSequence* MovieSceneSequence = RootTemplateInstance.GetSequence(MovieSceneSequenceID::Root);
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if (!MovieSceneSequence)
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{
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return;
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}
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#if !NO_LOGGING
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if (UE_LOG_ACTIVE(LogMovieScene, VeryVerbose))
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{
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const FQualifiedFrameTime CurrentTime = GetCurrentTime();
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const FString SequenceName = GetSequenceName(true);
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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());
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}
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#endif
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if (PlaybackClient)
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{
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PlaybackClient->WarpEvaluationRange(InRange);
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}
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// Once we have updated we must no longer skip updates
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bSkipNextUpdate = false;
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// We shouldn't be asked to run an async update if we have a blocking sequence.
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check(!Args.bIsAsync || !EnumHasAnyFlags(MovieSceneSequence->GetFlags(), EMovieSceneSequenceFlags::BlockingEvaluation));
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// We shouldn't be asked to run an async update if we don't have a tick manager.
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check(!Args.bIsAsync || TickManager != nullptr);
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FMovieSceneContext Context(InRange, PlayerStatus);
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Context.SetHasJumped(Args.bHasJumped);
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TSharedPtr<FMovieSceneEntitySystemRunner> Runner = RootTemplateInstance.GetRunner();
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if (Runner)
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{
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Runner->QueueUpdate(Context, RootTemplateInstance.GetRootInstanceHandle());
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if (Runner == SynchronousRunner || !Args.bIsAsync)
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{
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Runner->Flush();
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}
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}
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}
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```
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这段解析来自于：https://zhuanlan.zhihu.com/p/413151867
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```c++
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UMovieSceneSequencePlayer::Play() //蓝图中调用
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UMovieSceneSequencePlayer::PlayInternal()
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UMovieSceneSequencePlayer::UpdateMovieSceneInstance
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RootTemplateInstance.Evaluate(Context, *this);
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// FMovieSceneRootEvaluationTemplateInstance::Evaluate
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EntitySystemRunner.Update(Context, RootInstanceHandle);
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FMovieSceneEntitySystemRunner::Flush()
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FMovieSceneEntitySystemRunner::DoFlushUpdateQueueOnce()
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FMovieSceneEntitySystemRunner::GameThread_ProcessQueue()
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FMovieSceneEntitySystemRunner::GameThread_SpawnPhase()
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// FMovieSceneEntitySystemRunner::GameThread_SpawnPhase()
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/// System Linker->GetInstanceRegistry();
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FInstanceRegistry* InstanceRegistry = GetInstanceRegistry();
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FSequenceInstance& Instance = InstanceRegistry->MutateInstance(Update.InstanceHandle);
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Instance.Update(Linker, Update.Context);
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// FSequenceInstance::Update
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SequenceUpdater->Update(Linker, Params, ComponentField, EntitiesScratch);
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// FSequenceUpdater_Flat::Update
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FSequenceInstance& SequenceInstance = Linker->GetInstanceRegistry()->MutateInstance(InstanceHandle);
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SequenceInstance.Ledger.UpdateEntities
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// FEntityLedger::UpdateEntities
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FInstanceRegistry* InstanceRegistry = Linker->GetInstanceRegistry();
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ImportEntity(Linker, ImportParams, EntityField, Query);
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}
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```
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暂停的核心逻辑：
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```c++
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FMovieSceneEvaluationRange CurrentTimeRange = PlayPosition.GetCurrentPositionAsRange();
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const FMovieSceneContext Context(CurrentTimeRange, EMovieScenePlayerStatus::Stopped);
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Runner->QueueUpdate(Context, RootTemplateInstance.GetRootInstanceHandle(), FSimpleDelegate::CreateWeakLambda(this, FinishPause));
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```
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## SequenceRecorder
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SequenceRecorder模块的基类是ISequenceRecorder。
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# Sequencer ECS
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## 使用ECS的原因
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**可伸缩性**
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如果使用新的运行时，应该能够编写包含成百上千个轨道或序列的内容，并且将这些内容作为一个整体来优化求值逻辑。这包括：
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- 分配和组织数据，使性能不会随着活动Sequencer轨道的增加而快速恶化。
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- 能够完全删除已知不再需要的逻辑和分支，不必在每一帧都为它们付出成本。没有代码就是最快的代码。这条原则应该适用于Sequencer求值代码的所有方面，而不仅限于最高级。
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- 求值逻辑应该能够直接、高效且不受阻碍地批量访问必要数据，而不必通过复杂或低效的抽象与内存交互。
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**并发性**
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写入求值逻辑应该很简单，而且天然就能安全而高效地扩展到多个核心，包括上游/下游依赖性的表达定义（例如，并行地对所有曲线求值）。由于具备仅设置一次管线的综合优点，这不仅能让许多轻量级的小型动画受益，也有益于非常大的序列。
|
||
|
||
**可扩展性**
|
||
应该可以在内置功能的基础上构建逻辑，而不必重新实现核心系统。添加与核心系统交互的上游或下游功能应该是可以合理实现的。这包括：
|
||
- 在管线中的任何位置，当前帧的所有数据都应该是透明且可改变的。
|
||
- 可靠的依赖性管理。
|
||
|
||
这些设计目标，再加上Sequencer本身的各种问题，使得采用[数据导向的设计](https://en.wikipedia.org/wiki/Data-oriented_design)原则成为自然而然的选择，理由如下：
|
||
- 大部分Sequencer数据是同质的，可以循序布局。
|
||
- 每种数据变换的逻辑通常具有非常高的独立性，与情境无关（即运行函数f(x)来得到曲线）。
|
||
- 控制和数据流是非常线性的，没有循环或递归的依赖性（也就是说，没有一种逻辑会要求重新计算已经计算出的数值）。
|
||
- 只有初始设置和最终属性设置器才有线程限制。
|
||
|
||
可参考Tracker实现：
|
||
- https://www.unrealengine.com/marketplace/zh-CN/product/blueprintsequencertrack
|
||
- GeometryCacheTracks & GeometryCacheSequencer
|
||
- MovieSceneEventTrack
|
||
- MovieSceneEventSection
|
||
- UMovieSceneEventTriggerSection -> UMovieSceneEventSectionBase -> UMovieSceneSection
|
||
- UMovieSceneEventRepeaterSection -> UMovieSceneEventSectionBase -> UMovieSceneSection
|
||
- MovieSceneEventSystem
|
||
- MovieSceneEventChannel
|
||
## Sequencer 组件相关概念
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