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UE5 为啥原生的NotifyState写逻辑会有问题

news 2025/9/2 17:27:42

UE5 为啥原生的NotifyState写逻辑会有问题

虚幻的UAnimNotifyState，也就是Montage中配置的通知条存在明显的问题，请勿用来写逻辑，做表现是可以的。

UE5.3 相关源码：

void UAnimInstance::TriggerAnimNotifies(float DeltaSeconds)
{SCOPE_CYCLE_COUNTER(STAT_AnimTriggerAnimNotifies);USkeletalMeshComponent* SkelMeshComp = GetSkelMeshComponent();// Array that will replace the 'ActiveAnimNotifyState' at the end of this function.TArray<FAnimNotifyEvent> NewActiveAnimNotifyState;NewActiveAnimNotifyState.Reserve(NotifyQueue.AnimNotifies.Num());TArray<FAnimNotifyEventReference> NewActiveAnimNotifyEventReference;NewActiveAnimNotifyEventReference.Reserve(NotifyQueue.AnimNotifies.Num());// AnimNotifyState freshly added that need their 'NotifyBegin' event called.TArray<const FAnimNotifyEvent *> NotifyStateBeginEvent;TArray<const FAnimNotifyEventReference *> NotifyStateBeginEventReference;for (int32 Index=0; Index<NotifyQueue.AnimNotifies.Num(); Index++){if(const FAnimNotifyEvent* AnimNotifyEvent = NotifyQueue.AnimNotifies[Index].GetNotify()){// AnimNotifyStateif (AnimNotifyEvent->NotifyStateClass){int32 ExistingItemIndex = INDEX_NONE;if (ActiveAnimNotifyState.Find(*AnimNotifyEvent, ExistingItemIndex)){check(ActiveAnimNotifyState.Num() == ActiveAnimNotifyEventReference.Num());ActiveAnimNotifyState.RemoveAtSwap(ExistingItemIndex, 1, false); ActiveAnimNotifyEventReference.RemoveAtSwap(ExistingItemIndex, 1, false);}else{NotifyStateBeginEvent.Add(AnimNotifyEvent);NotifyStateBeginEventReference.Add(&NotifyQueue.AnimNotifies[Index]);}NewActiveAnimNotifyState.Add(*AnimNotifyEvent);FAnimNotifyEventReference& EventRef = NewActiveAnimNotifyEventReference.Add_GetRef(NotifyQueue.AnimNotifies[Index]);EventRef.SetNotify(&NewActiveAnimNotifyState.Top());continue;}// Trigger non 'state' AnimNotifiesTriggerSingleAnimNotify(NotifyQueue.AnimNotifies[Index]);}}// Send end notification to AnimNotifyState not active anymore.for (int32 Index = 0; Index < ActiveAnimNotifyState.Num(); ++Index){const FAnimNotifyEvent& AnimNotifyEvent = ActiveAnimNotifyState[Index];const FAnimNotifyEventReference& EventReference = ActiveAnimNotifyEventReference[Index];if (AnimNotifyEvent.NotifyStateClass && ShouldTriggerAnimNotifyState(AnimNotifyEvent.NotifyStateClass)){
#if WITH_EDITOR// Prevent firing notifies in animation editors if requested if(!SkelMeshComp->IsA<UDebugSkelMeshComponent>() || AnimNotifyEvent.NotifyStateClass->ShouldFireInEditor())
#endif{TRACE_ANIM_NOTIFY(this, AnimNotifyEvent, End);AnimNotifyEvent.NotifyStateClass->NotifyEnd(SkelMeshComp, Cast<UAnimSequenceBase>(AnimNotifyEvent.NotifyStateClass->GetOuter()), EventReference);}}// The NotifyEnd callback above may have triggered actor destruction and the tear down// of this instance via UninitializeAnimation which empties ActiveAnimNotifyState.// If that happened, we should stop iterating the ActiveAnimNotifyState arrayif (ActiveAnimNotifyState.IsValidIndex(Index) == false){ensureMsgf(false, TEXT("UAnimInstance::ActiveAnimNotifyState has been invalidated by NotifyEnd. AnimInstance: %s, Owning Component: %s, Owning Actor: %s "), *GetNameSafe(this), *GetNameSafe(GetOwningComponent()), *GetNameSafe(GetOwningActor()));return;}}check(NotifyStateBeginEventReference.Num() == NotifyStateBeginEvent.Num());for (int32 Index = 0; Index < NotifyStateBeginEvent.Num(); Index++){const FAnimNotifyEvent* AnimNotifyEvent = NotifyStateBeginEvent[Index];const FAnimNotifyEventReference * AnimNotifyEventReference = NotifyStateBeginEventReference[Index];if (ShouldTriggerAnimNotifyState(AnimNotifyEvent->NotifyStateClass)){
#if WITH_EDITOR// Prevent firing notifies in animation editors if requested if(!SkelMeshComp->IsA<UDebugSkelMeshComponent>() || AnimNotifyEvent->NotifyStateClass->ShouldFireInEditor())
#endif{TRACE_ANIM_NOTIFY(this, *AnimNotifyEvent, Begin);AnimNotifyEvent->NotifyStateClass->NotifyBegin(SkelMeshComp, Cast<UAnimSequenceBase>(AnimNotifyEvent->NotifyStateClass->GetOuter()), AnimNotifyEvent->GetDuration(), *AnimNotifyEventReference);}}}// Switch our arrays.ActiveAnimNotifyState = MoveTemp(NewActiveAnimNotifyState);ActiveAnimNotifyEventReference = MoveTemp(NewActiveAnimNotifyEventReference);// Tick currently active AnimNotifyStatefor (int32 Index = 0; Index < ActiveAnimNotifyState.Num(); Index++){const FAnimNotifyEvent& AnimNotifyEvent = ActiveAnimNotifyState[Index];const FAnimNotifyEventReference& EventReference = ActiveAnimNotifyEventReference[Index];if (ShouldTriggerAnimNotifyState(AnimNotifyEvent.NotifyStateClass)){
#if WITH_EDITOR// Prevent firing notifies in animation editors if requested if(!SkelMeshComp->IsA<UDebugSkelMeshComponent>() || AnimNotifyEvent.NotifyStateClass->ShouldFireInEditor())
#endif{TRACE_ANIM_NOTIFY(this, AnimNotifyEvent, Tick);AnimNotifyEvent.NotifyStateClass->NotifyTick(SkelMeshComp, Cast<UAnimSequenceBase>(AnimNotifyEvent.NotifyStateClass->GetOuter()), DeltaSeconds, EventReference);}}}
}

问题一：同帧下的Begin 与End，它是按For循环执行的，没有按照时间顺序执行。如下图的NotifyStateA与NotifyStateB，他们在第N帧的时候，A的End会要比B的Start先执行，但是在时间的顺序上，B的Begin时间是早于A的End的，如果依赖时间顺序去执行，某些代码逻辑时候，当卡的时候，逻辑必有问题。
在这里插入图片描述
问题二：它没有上下执行顺序的问题，并不是同一时间下上面的先执行。
问题三：同一帧里面有NotifyState的Start 与 End，那么End会在下一帧执行，而不是同帧下执行