书接 11. UE5 RPG使用GameplayEffect修改角色属性（二）
前面，介绍了GameplayEffect的Instant和Duration的使用，这一篇主要介绍一下无限制时间类型的infinite的使用方式。
无限时间限制模式下，如果你的周期时间（Period）为0，那就是相当于增加了一个状态加了一个Buff，效果是持续的，如果周期时间你设置了值，那么它将变成为每个周期执行一次Instant效果的GameplayEffect。
使用起来基本上和有时间限制的Duration一样，它们的区别在于，一个是有时间限制的，另一个是没有时间限制。

应用场景

  1. 可以使用到地面陷阱，比如地上的岩浆，角色站在上面会一直掉血，离开后，通过清除GameplayEffect来取消效果。
  2. 恢复水泉，角色站在旁边可以一直恢复。
  3. 无限制时间的buff，比如装备提供的buff，角色特有的属性bufff。

接下来，我们要制作一个通用的类，里面可以设置这三种属性的GameplayEffect，在蓝图里面，只需要设置何时触发效果即可。并且实现一下Infinite效果的添加和删除功能。

首先我们要添加两个枚举，用于设置添加的类在何时应用到actor身上

//效果应用状态枚举UENUM(BlueprintType) enum class EEffectApplicationPolicy{ApplyOnOverlap,ApplyOnEndOverlap,DoNotApply};//效果移除的状态枚举UENUM(BlueprintType) enum class EEffectRemovalPolicy{RemoveOnEndOverlap,DoNotRemove};

接着修改配置项的类，每一种GameplayEffect的类，Instant和Duration只有添加时的策略配置，（它们两个一个是瞬间效果，另一个是有时效性的，都不需要主动移除），Infinite的则需要设置添加策略和移除策略。

UPROPERTY(EditAnywhere, BlueprintReadOnly, Category="Apply Effects")TSubclassOf<UGameplayEffect> InstantGameplayEffectClass; //生成GameplayEffect的类UPROPERTY(EditAnywhere, BlueprintReadOnly, Category="Apply Effects")EEffectApplicationPolicy InstantEffectApplicationPolicy = EEffectApplicationPolicy::DoNotApply;UPROPERTY(EditAnywhere, BlueprintReadOnly, Category="Apply Effects")TSubclassOf<UGameplayEffect> DurationGameplayEffectClass; //生成具有一定持续时间的GameplayEffect的类UPROPERTY(EditAnywhere, BlueprintReadOnly, Category="Apply Effects")EEffectApplicationPolicy DurationEffectApplicationPolicy = EEffectApplicationPolicy::DoNotApply;UPROPERTY(EditAnywhere, BlueprintReadOnly, Category="Apply Effects")TSubclassOf<UGameplayEffect> InfinityGameplayEffectClass; //生成具有一定持续时间的GameplayEffect的类UPROPERTY(EditAnywhere, BlueprintReadOnly, Category="Apply Effects")EEffectApplicationPolicy InfinityEffectApplicationPolicy = EEffectApplicationPolicy::DoNotApply;UPROPERTY(EditAnywhere, BlueprintReadOnly, Category="Apply Effects")EEffectRemovalPolicy InfinityEffectRemovalPolicy = EEffectRemovalPolicy::RemoveOnEndOverlap;

接着，我们需要创建两个函数，可以在蓝图中调用，触发overlap和endoverlap时的相关事件

//在重叠开始时处理效果的添加删除逻辑UFUNCTION(BlueprintCallable) void OnOverlap(AActor* TargetActor);//在重叠结束时处理效果的添加删除逻辑UFUNCTION(BlueprintCallable) void OnEndOverlap(AActor* TargetActor);

在Overlap事件中，如果你设置了对应的需要在Overlap时添加效果，将去执行ApplyEffectToTarget()函数应用效果。

void AEffectActorBase::OnOverlap(AActor* TargetActor){if(InstantEffectApplicationPolicy == EEffectApplicationPolicy::ApplyOnOverlap){ApplyEffectToTarget(TargetActor, InstantGameplayEffectClass);}if(DurationEffectApplicationPolicy == EEffectApplicationPolicy::ApplyOnOverlap){ApplyEffectToTarget(TargetActor, DurationGameplayEffectClass);}if(InfinityEffectApplicationPolicy == EEffectApplicationPolicy::ApplyOnOverlap){ApplyEffectToTarget(TargetActor, InfinityGameplayEffectClass);}}

ApplyEffectToTarget()函数之前也讲过，这里有了更改，就是对于Infinite类型的效果并且在重叠结束时需要销毁的效果，我们需要将其的引用保存下来，因为它不会自己取消，需要手动去销毁。

void AEffectActorBase::ApplyEffectToTarget(AActor* TargetActor, TSubclassOf<UGameplayEffect> GameplayEffectClass){/*** 默认自己编写从actor身上获取ASC的方式* IAbilitySystemInterface* ASCInterface = Cast(TargetActor); //判断当前actor是否有技能系统接口if(ASCInterface){UAbilitySystemComponent* TargetASC = ASCInterface->GetAbilitySystemComponent(); } *///获取ASCUAbilitySystemComponent* TargetASC = UAbilitySystemBlueprintLibrary::GetAbilitySystemComponent(TargetActor);if(TargetASC == nullptr) return;check(GameplayEffectClass);//创建Effect的句柄 包含了实例化Effect所需数据FGameplayEffectContextHandle EffectContextHandle = TargetASC->MakeEffectContext();//设置创建Effect的对象EffectContextHandle.AddSourceObject(this);//Effect的实例化后的句柄，可以通过此来寻找调用const FGameplayEffectSpecHandle EffectSpecHandle = TargetASC->MakeOutgoingSpec(GameplayEffectClass, 1.f, EffectContextHandle);//从句柄中获取到实例的地址，并被应用。const FActiveGameplayEffectHandle ActiveGameplayEffectHandle = TargetASC->ApplyGameplayEffectSpecToSelf(*EffectSpecHandle.Data.Get());//从句柄中获取到定义的对象，并判断设置的const bool bIsInfinite = EffectSpecHandle.Data.Get()->Def.Get()->DurationPolicy == EGameplayEffectDurationType::Infinite;//在是无限时间效果和需要在结束时清除掉时，将效果句柄添加到mapif(bIsInfinite && InfinityEffectRemovalPolicy == EEffectRemovalPolicy::RemoveOnEndOverlap){ActiveEffectHandles.Add(ActiveGameplayEffectHandle, TargetASC);}}

在结束重叠事件函数中，首先逻辑判断是否需要在离开时添加效果。接下来就是判断Infinite类型的效果是否需要在结束重叠事件时移除，如果需要则通过ASC判断相同来找到对应的效果进行移除，在堆栈里面还不能直接移除，所以先将引用保存了下来

void AEffectActorBase::OnEndOverlap(AActor* TargetActor){//添加效果if(InstantEffectApplicationPolicy == EEffectApplicationPolicy::ApplyOnEndOverlap){ApplyEffectToTarget(TargetActor, InstantGameplayEffectClass);}if(DurationEffectApplicationPolicy == EEffectApplicationPolicy::ApplyOnEndOverlap){ApplyEffectToTarget(TargetActor, DurationGameplayEffectClass);}if(InfinityEffectApplicationPolicy == EEffectApplicationPolicy::ApplyOnEndOverlap){ApplyEffectToTarget(TargetActor, InfinityGameplayEffectClass);}//删除效果if(InfinityEffectRemovalPolicy == EEffectRemovalPolicy::RemoveOnEndOverlap){UAbilitySystemComponent* TargetASC = UAbilitySystemBlueprintLibrary::GetAbilitySystemComponent(TargetActor);if(!IsValid(TargetASC)) return;//创建存储需要移除的效果句柄存储Key，用于遍历完成后移除效果TArray<FActiveGameplayEffectHandle> HandlesToRemove;//循环map内存的数据for(TTuple<FActiveGameplayEffectHandle, UAbilitySystemComponent*> HandlePair : ActiveEffectHandles){//判断是否ASC相同if(TargetASC == HandlePair.Value){//通过句柄将效果移除，注意，有可能有多层效果，不能将其它层的效果也移除掉，所以只移除一层TargetASC->RemoveActiveGameplayEffect(HandlePair.Key, 1);//添加到移除列表HandlesToRemove.Add(HandlePair.Key);}}//遍历完成后，在Map中将移除效果的KeyValue删除for(auto& Handle : HandlesToRemove){ActiveEffectHandles.FindAndRemoveChecked(Handle);}}}

接着编译打开ue，看到右侧有对应的属性配置

事件图表更好设置，在对应的碰撞体事件触发回调时链接即可

GameplayEffect的设置就很简单了，一个持续掉血的效果

接下来就是测试，运行起来，点击~键，然后输入showdebug abilitysystem 来查看掉血情况

下面附上上面两个文件的整个代码：
EffectActorBase.h

// 版权归暮志未晚所有。#pragma once#include "CoreMinimal.h"#include "GameFramework/Actor.h"#include "GameplayEffectTypes.h"#include "EffectActorBase.generated.h"struct FActiveGameplayEffectHandle;class UAbilitySystemComponent;class UGameplayEffect;//效果应用状态枚举UENUM(BlueprintType) enum class EEffectApplicationPolicy{ApplyOnOverlap,ApplyOnEndOverlap,DoNotApply};//效果移除的状态枚举UENUM(BlueprintType) enum class EEffectRemovalPolicy{RemoveOnEndOverlap,DoNotRemove};/** * 在场景中可放置的影响角色属性的物件基类 */UCLASS()class AURA_API AEffectActorBase : public AActor{GENERATED_BODY()public:AEffectActorBase();protected:// 游戏开始或生成对象时回调virtual void BeginPlay() override;//给与目标添加GameplayEffect效果UFUNCTION(BlueprintCallable) void ApplyEffectToTarget(AActor* TargetActor, TSubclassOf<UGameplayEffect> GameplayEffectClass);//在重叠开始时处理效果的添加删除逻辑UFUNCTION(BlueprintCallable) void OnOverlap(AActor* TargetActor);//在重叠结束时处理效果的添加删除逻辑UFUNCTION(BlueprintCallable) void OnEndOverlap(AActor* TargetActor);UPROPERTY(EditAnywhere, BlueprintReadOnly, Category="Apply Effects")TSubclassOf<UGameplayEffect> InstantGameplayEffectClass; //生成GameplayEffect的类UPROPERTY(EditAnywhere, BlueprintReadOnly, Category="Apply Effects")EEffectApplicationPolicy InstantEffectApplicationPolicy = EEffectApplicationPolicy::DoNotApply;UPROPERTY(EditAnywhere, BlueprintReadOnly, Category="Apply Effects")TSubclassOf<UGameplayEffect> DurationGameplayEffectClass; //生成具有一定持续时间的GameplayEffect的类UPROPERTY(EditAnywhere, BlueprintReadOnly, Category="Apply Effects")EEffectApplicationPolicy DurationEffectApplicationPolicy = EEffectApplicationPolicy::DoNotApply;UPROPERTY(EditAnywhere, BlueprintReadOnly, Category="Apply Effects")TSubclassOf<UGameplayEffect> InfinityGameplayEffectClass; //生成具有一定持续时间的GameplayEffect的类UPROPERTY(EditAnywhere, BlueprintReadOnly, Category="Apply Effects")EEffectApplicationPolicy InfinityEffectApplicationPolicy = EEffectApplicationPolicy::DoNotApply;UPROPERTY(EditAnywhere, BlueprintReadOnly, Category="Apply Effects")EEffectRemovalPolicy InfinityEffectRemovalPolicy = EEffectRemovalPolicy::RemoveOnEndOverlap;//用于存储当前已经激活的GameplayEffect的句柄的mapTMap<FActiveGameplayEffectHandle, UAbilitySystemComponent*> ActiveEffectHandles;};

EffectActorBase.cpp

// 版权归暮志未晚所有。#include "Actor/EffectActorBase.h"#include "ActiveGameplayEffectHandle.h"#include "AbilitySystemBlueprintLibrary.h"#include "AbilitySystemComponent.h"AEffectActorBase::AEffectActorBase(){ // 设置当前对象是否每帧调用Tick()PrimaryActorTick.bCanEverTick = false;SetRootComponent(CreateDefaultSubobject<USceneComponent>("SceneRoot"));}void AEffectActorBase::BeginPlay(){Super::BeginPlay();}void AEffectActorBase::ApplyEffectToTarget(AActor* TargetActor, TSubclassOf<UGameplayEffect> GameplayEffectClass){/*** 默认自己编写从actor身上获取ASC的方式* IAbilitySystemInterface* ASCInterface = Cast(TargetActor); //判断当前actor是否有技能系统接口if(ASCInterface){UAbilitySystemComponent* TargetASC = ASCInterface->GetAbilitySystemComponent(); } *///获取ASCUAbilitySystemComponent* TargetASC = UAbilitySystemBlueprintLibrary::GetAbilitySystemComponent(TargetActor);if(TargetASC == nullptr) return;check(GameplayEffectClass);//创建Effect的句柄 包含了实例化Effect所需数据FGameplayEffectContextHandle EffectContextHandle = TargetASC->MakeEffectContext();//设置创建Effect的对象EffectContextHandle.AddSourceObject(this);//Effect的实例化后的句柄，可以通过此来寻找调用const FGameplayEffectSpecHandle EffectSpecHandle = TargetASC->MakeOutgoingSpec(GameplayEffectClass, 1.f, EffectContextHandle);//从句柄中获取到实例的地址，并被应用。const FActiveGameplayEffectHandle ActiveGameplayEffectHandle = TargetASC->ApplyGameplayEffectSpecToSelf(*EffectSpecHandle.Data.Get());//从句柄中获取到定义的对象，并判断设置的const bool bIsInfinite = EffectSpecHandle.Data.Get()->Def.Get()->DurationPolicy == EGameplayEffectDurationType::Infinite;//在是无限时间效果和需要在结束时清除掉时，将效果句柄添加到mapif(bIsInfinite && InfinityEffectRemovalPolicy == EEffectRemovalPolicy::RemoveOnEndOverlap){ActiveEffectHandles.Add(ActiveGameplayEffectHandle, TargetASC);}}void AEffectActorBase::OnOverlap(AActor* TargetActor){if(InstantEffectApplicationPolicy == EEffectApplicationPolicy::ApplyOnOverlap){ApplyEffectToTarget(TargetActor, InstantGameplayEffectClass);}if(DurationEffectApplicationPolicy == EEffectApplicationPolicy::ApplyOnOverlap){ApplyEffectToTarget(TargetActor, DurationGameplayEffectClass);}if(InfinityEffectApplicationPolicy == EEffectApplicationPolicy::ApplyOnOverlap){ApplyEffectToTarget(TargetActor, InfinityGameplayEffectClass);}}void AEffectActorBase::OnEndOverlap(AActor* TargetActor){//添加效果if(InstantEffectApplicationPolicy == EEffectApplicationPolicy::ApplyOnEndOverlap){ApplyEffectToTarget(TargetActor, InstantGameplayEffectClass);}if(DurationEffectApplicationPolicy == EEffectApplicationPolicy::ApplyOnEndOverlap){ApplyEffectToTarget(TargetActor, DurationGameplayEffectClass);}if(InfinityEffectApplicationPolicy == EEffectApplicationPolicy::ApplyOnEndOverlap){ApplyEffectToTarget(TargetActor, InfinityGameplayEffectClass);}//删除效果if(InfinityEffectRemovalPolicy == EEffectRemovalPolicy::RemoveOnEndOverlap){UAbilitySystemComponent* TargetASC = UAbilitySystemBlueprintLibrary::GetAbilitySystemComponent(TargetActor);if(!IsValid(TargetASC)) return;//创建存储需要移除的效果句柄存储Key，用于遍历完成后移除效果TArray<FActiveGameplayEffectHandle> HandlesToRemove;//循环map内存的数据for(TTuple<FActiveGameplayEffectHandle, UAbilitySystemComponent*> HandlePair : ActiveEffectHandles){//判断是否ASC相同if(TargetASC == HandlePair.Value){//通过句柄将效果移除，注意，有可能有多层效果，不能将其它层的效果也移除掉，所以只移除一层TargetASC->RemoveActiveGameplayEffect(HandlePair.Key, 1);//添加到移除列表HandlesToRemove.Add(HandlePair.Key);}}//遍历完成后，在Map中将移除效果的KeyValue删除for(auto& Handle : HandlesToRemove){ActiveEffectHandles.FindAndRemoveChecked(Handle);}}}