逻辑状态机

为了实现对目标状态的控制，以及广播改变状态后的事件，可在蓝图中继续处理不同状态下的行为。

实现过程：

1.继承ActorComponent实现LogicStateMachine；

2.被击中时触发设置状态；

3.状态进入/退出时触发事件。

主要代码

LogicStateMachine.h

/*

*author : Jia Zhipeng

*class : LogicStateMachine

*/

//use enum metadata to save priority

UENUM(BlueprintType)

enum LogicStateEnum

{

	LS_Default = 0 	UMETA(DisplayName = "Default", Priority = 1),

	LS_Frozen	UMETA(DisplayName = "Frozen", Priority = 1),

	LS_Fly 	UMETA(DisplayName = "Fly", Priority = 1),

	LS_OnGround 	UMETA(DisplayName = "OnGround", Priority = 1),

	LS_Faint 	UMETA(DisplayName = "Faint", Priority = 1),

	LS_Back		UMETA(DisplayName = "Back", Priority = 1),

	LogicStateNum  UMETA(Hidden),

};

DECLARE_DYNAMIC_MULTICAST_DELEGATE_OneParam(FChangeStateSignature, LogicStateEnum, LogicState);

UCLASS(ClassGroup = LogicState, meta = (BlueprintSpawnableComponent), ShowCategories = (LogicState))

class CLIENT_API ULogicStateMachine : public UActorComponent

{

	GENERATED_UCLASS_BODY()

public:

	//After during time, state will be reset to default.

	UFUNCTION(BlueprintCallable, Category = LogicStateMachine)

		bool SetState(LogicStateEnum NewState, float DuringTime=1.0f);

	//Event used in BP

	UPROPERTY(BlueprintAssignable, Category = LogicStateMachine)

		FChangeStateSignature OnEnterLogicState;

	UPROPERTY(BlueprintAssignable, Category = LogicStateMachine)

		FChangeStateSignature OnRefreshLogicState;

	UPROPERTY(BlueprintAssignable, Category = LogicStateMachine)

		FChangeStateSignature OnExitLogicState;

	virtual void TickComponent(float DeltaTime, enum ELevelTick TickType, FActorComponentTickFunction *ThisTickFunction) override;

	virtual void OnRegister() override;

	float GetElapsedTime() { return ElapsedTime; }

	void SetElapsedTime(float Time) {	ElapsedTime = Time;	}

private:

	LogicStateEnum CurrentState;

	//On currentState time

	float ElapsedTime;

	//after this time, it will be reset to Default

	float ResetToDefaultTime;

};

LogicStateMachine.cpp

/*

*author : Jia Zhipeng

*class : LogicStateMachine

*/

//主要改变状态代码

bool ULogicStateMachine::SetState(LogicStateEnum NewState, float DuringTime)

{

	int NewStatePriority = 0;

	int CurrentStatePriority = 0;

	const UEnum* EnumPtr = FindObject<UEnum>(ANY_PACKAGE, TEXT("LogicStateEnum"), true);

	FString str = EnumPtr->GetMetaData(TEXT("Priority"), CurrentState);

	if (!str.IsEmpty())

		CurrentStatePriority = FCString::Atoi(*str);

	str = EnumPtr->GetMetaData(TEXT("Priority"), NewState);

	if (!str.IsEmpty())

		NewStatePriority = FCString::Atoi(*str);

	//根据优先级判断是否改变/刷新状态

	if ( (NewState != LogicStateEnum::LS_Default) && (NewStatePriority<CurrentStatePriority))

		return false;

	//Time record

	ElapsedTime = 0;

	ResetToDefaultTime = DuringTime;

	//状态相同则刷新，不同则退出旧状态，进入新状态

	if (NewState == CurrentState)

		OnRefreshLogicState.Broadcast(CurrentState);

	if (NewState != CurrentState)

	{

		OnExitLogicState.Broadcast(CurrentState);

	}

	CurrentState = NewState;

	OnEnterLogicState.Broadcast(CurrentState);

	return true;

}