虚幻引擎5 GAS开发俯视角RPG游戏 #06-11：游戏后效果执行
本文介绍了GameplayAbilitySystem中PostGameplayEffectExecute函数的实现与应用。该函数在数值变化后触发，主要用于Instant类GameplayEffect（Duration和Infinite类若设置Period也可触发）。文章详细展示了如何通过该函数修正数值（相比PreAttributeChange能真正修改数值），并演示了血量、蓝量等属性的安全范围控制。同时，定义了FEffectProperties结构体封装GE相关对象，提供了SetEffectProperties方法统一处理施放者和目标的对象引用获取，为后续逻辑处理提供便利。这些实现可用于死亡判定、无敌状态等游戏逻辑处理。
1.PostGameplayEffectExecute
PostGameplayEffectExecute()函数是在数值变化后触发的，一般只会在Instant类型的GameplayEffect才可以触发（Duration和Infinite类的GameplayEffect如果设置Period也可以触发）。
并且，我们还可以在这里面去修正数值，（在PreAttributeChange回调里面，只能修正显示的结果，实际结果没有变）。
这个函数的应用场景很多，我们可以做一些逻辑操作，比如死亡，无敌不扣血等等。
Source/CC_Aura/Public/AbilitySystem/CC_AttributeSet.h:
//属性更改后的方法virtual void PostGameplayEffectExecute(const struct FGameplayEffectModCallbackData& Data) override;Source/CC_Aura/Private/AbilitySystem/CC_AttributeSet.cpp:
void UCC_AttributeSet::PostGameplayEffectExecute(const struct FGameplayEffectModCallbackData& Data)
{Super::PostGameplayEffectExecute(Data);if (Data.EvaluatedData.Attribute == GetHealthAttribute()){UE_LOG(LogTemp, Warning, TEXT("Health: %f"), GetHealth());UE_LOG(LogTemp, Warning, TEXT("Magnitude: %f"), Data.EvaluatedData.Magnitude);}
}2.接下来，我们将从Data中获取到需要的然后封装成一个结构体，方便后续使用。
Source/CC_Aura/Public/AbilitySystem/CC_AttributeSet.h:
// 用于存储施放GE的相关对象和目标的相关对象
USTRUCT()
struct FEffectProperties
{GENERATED_BODY()FEffectProperties(){}FGameplayEffectContextHandle EffectContextHandle;UPROPERTY()UAbilitySystemComponent* SourceASC = nullptr;UPROPERTY()AActor* SourceAvatarActor = nullptr;UPROPERTY()AController* SourceController = nullptr;UPROPERTY()ACharacter* SourceCharacter = nullptr;UPROPERTY()UAbilitySystemComponent* TargetASC = nullptr;UPROPERTY()AActor* TargetAvatarActor = nullptr;UPROPERTY()AController* TargetController = nullptr;UPROPERTY()ACharacter* TargetCharacter = nullptr;
};3.创建私有函数,给FEffectProperties赋值
Source/CC_Aura/Public/AbilitySystem/CC_AttributeSet.h:
private:void SetEffectProperties(const struct FGameplayEffectModCallbackData& Data, FEffectProperties& Props) const;Source/CC_Aura/Private/AbilitySystem/CC_AttributeSet.cpp:
void UCC_AttributeSet::SetEffectProperties(const struct FGameplayEffectModCallbackData& Data, FEffectProperties& Props) const
{Props.EffectContextHandle = Data.EffectSpec.GetContext();//获取效果所有者的相关对象Props.SourceASC = Props.EffectContextHandle.GetOriginalInstigatorAbilitySystemComponent(); //获取SourceASCif(IsValid(Props.SourceASC) && Props.SourceASC->AbilityActorInfo.IsValid() && Props.SourceASC->AbilityActorInfo->AvatarActor.IsValid()){Props.SourceAvatarActor = Props.SourceASC->AbilityActorInfo->AvatarActor.Get(); //获取SourceAvatarActorProps.SourceController = Props.SourceASC->AbilityActorInfo->PlayerController.Get(); //获取SourceControllerif(Props.SourceController == nullptr && Props.SourceAvatarActor != nullptr){if(const APawn* Pawn = Cast<APawn>(Props.SourceAvatarActor)){Props.SourceController = Pawn->GetController();}}if(Props.SourceController){Props.SourceCharacter = Cast<ACharacter>(Props.SourceController->GetPawn()); //获取SourceCharacter}}if(Data.Target.AbilityActorInfo.IsValid() && Data.Target.AbilityActorInfo->AvatarActor.IsValid()){Props.TargetAvatarActor = Data.Target.AbilityActorInfo->AvatarActor.Get();Props.TargetController = Data.Target.AbilityActorInfo->PlayerController.Get();Props.TargetCharacter = Cast<ACharacter>(Props.TargetAvatarActor);Props.TargetASC = UAbilitySystemBlueprintLibrary::GetAbilitySystemComponent(Props.TargetAvatarActor);}
}
4.将方法添加到PostGameplayEffectExecute函数里:
void UCC_AttributeSet::PostGameplayEffectExecute(const struct FGameplayEffectModCallbackData& Data)
{Super::PostGameplayEffectExecute(Data);FEffectProperties Props;SetEffectProperties(Data, Props);if(Data.EvaluatedData.Attribute == GetHealthAttribute()){SetHealth(FMath::Clamp(GetHealth(), 0.f, GetMaxHealth()));}if(Data.EvaluatedData.Attribute == GetManaAttribute()){SetMana(FMath::Clamp(GetMana(), 0.f, GetMaxMana()));}}