BlueRoseNote/03-UnrealEngine/Gameplay/GAS/(10)GAS 通过动画时间轴添加GameplayEffect.md

前言

之前使用GameplayTasks的事件处理会出现延迟问题。具体体现在如果使用机制来添加BlockAbilityTag，在狂按技能的情况下会出现Tag不能正常生成导致可以不停ActivateAbility的问题。

问题成因

1. 问题的原因就是使用GameplayTasks不能即时添加GE，会有一定延迟。
2. 清除GameplayEffect方式有问题，应该使用只清除该技能所附加的GE。

解决思路

在解决清除GE问题的情况下：

1. GASDocument中的解决方法：使用AbilityTag作为BlockAbilityTag，之后通过AnimNotify发送EndAbility事件Tag，提前结束Ability。（不会结束掉Montage播放）
2. 在AnimNotifyBegin函数中直接添加GE，根据TotalDuration设置持续时间。（但如果Montage突然被中断，就很难操作了，而且这样会与Ability耦合）
3. 增加公共CD（测试过效果不佳）

PlayMontage修改

1. 传递事件使用专门的Event.Montage.xxxx作为事件标签
2. 重写AnimNotify的GetNotifyName函数，使用标签名作为AnimNotify的显示名称。

void UGDGA_FireGun::EventReceived(FGameplayTag EventTag, FGameplayEventData EventData)
{
	// Montage told us to end the ability before the montage finished playing.
	// Montage was set to continue playing animation even after ability ends so this is okay.
	if (EventTag == FGameplayTag::RequestGameplayTag(FName("Event.Montage.EndAbility")))
	{
		EndAbility(CurrentSpecHandle, CurrentActorInfo, CurrentActivationInfo, true, false);
		return;
	}

	// Only spawn projectiles on the Server.
	// Predicting projectiles is an advanced topic not covered in this example.
	if (GetOwningActorFromActorInfo()->GetLocalRole() == ROLE_Authority && EventTag == FGameplayTag::RequestGameplayTag(FName("Event.Montage.SpawnProjectile")))
	{
		AGDHeroCharacter* Hero = Cast<AGDHeroCharacter>(GetAvatarActorFromActorInfo());
		if (!Hero)
		{
			EndAbility(CurrentSpecHandle, CurrentActorInfo, CurrentActivationInfo, true, true);
		}

		FVector Start = Hero->GetGunComponent()->GetSocketLocation(FName("Muzzle"));
		FVector End = Hero->GetCameraBoom()->GetComponentLocation() + Hero->GetFollowCamera()->GetForwardVector() * Range;
		FRotator Rotation = UKismetMathLibrary::FindLookAtRotation(Start, End);

		FGameplayEffectSpecHandle DamageEffectSpecHandle = MakeOutgoingGameplayEffectSpec(DamageGameplayEffect, GetAbilityLevel());
		
		// Pass the damage to the Damage Execution Calculation through a SetByCaller value on the GameplayEffectSpec
		DamageEffectSpecHandle.Data.Get()->SetSetByCallerMagnitude(FGameplayTag::RequestGameplayTag(FName("Data.Damage")), Damage);

		FTransform MuzzleTransform = Hero->GetGunComponent()->GetSocketTransform(FName("Muzzle"));
		MuzzleTransform.SetRotation(Rotation.Quaternion());
		MuzzleTransform.SetScale3D(FVector(1.0f));

		FActorSpawnParameters SpawnParameters;
		SpawnParameters.SpawnCollisionHandlingOverride = ESpawnActorCollisionHandlingMethod::AlwaysSpawn;

		AGDProjectile* Projectile = GetWorld()->SpawnActorDeferred<AGDProjectile>(ProjectileClass, MuzzleTransform, GetOwningActorFromActorInfo(),
			Hero, ESpawnActorCollisionHandlingMethod::AlwaysSpawn);
		Projectile->DamageEffectSpecHandle = DamageEffectSpecHandle;
		Projectile->Range = Range;
		Projectile->FinishSpawning(MuzzleTransform);
	}
}

	/** Apply a gameplay effect to the owner of this ability */
	UFUNCTION(BlueprintCallable, Category = Ability, DisplayName="ApplyGameplayEffectToOwner", meta=(ScriptName="ApplyGameplayEffectToOwner"))
	FActiveGameplayEffectHandle BP_ApplyGameplayEffectToOwner(TSubclassOf<UGameplayEffect> GameplayEffectClass, int32 GameplayEffectLevel = 1, int32 Stacks = 1);

	/** Non blueprintcallable, safe to call on CDO/NonInstance abilities */
	FActiveGameplayEffectHandle ApplyGameplayEffectToOwner(const FGameplayAbilitySpecHandle Handle, const FGameplayAbilityActorInfo* ActorInfo, const FGameplayAbilityActivationInfo ActivationInfo, const UGameplayEffect* GameplayEffect, float GameplayEffectLevel, int32 Stacks = 1) const;

	/** Apply a previously created gameplay effect spec to the owner of this ability */
	UFUNCTION(BlueprintCallable, Category = Ability, DisplayName = "ApplyGameplayEffectSpecToOwner", meta=(ScriptName = "ApplyGameplayEffectSpecToOwner"))
	FActiveGameplayEffectHandle K2_ApplyGameplayEffectSpecToOwner(const FGameplayEffectSpecHandle EffectSpecHandle);

	FActiveGameplayEffectHandle ApplyGameplayEffectSpecToOwner(const FGameplayAbilitySpecHandle AbilityHandle, const FGameplayAbilityActorInfo* ActorInfo, const FGameplayAbilityActivationInfo ActivationInfo, const FGameplayEffectSpecHandle SpecHandle) const;

	// -------------------------------------
	//  Apply Gameplay effects to Target
	// -------------------------------------

	/** Apply a gameplay effect to a Target */
	UFUNCTION(BlueprintCallable, Category = Ability, DisplayName = "ApplyGameplayEffectToTarget", meta=(ScriptName = "ApplyGameplayEffectToTarget"))
	TArray<FActiveGameplayEffectHandle> BP_ApplyGameplayEffectToTarget(FGameplayAbilityTargetDataHandle TargetData, TSubclassOf<UGameplayEffect> GameplayEffectClass, int32 GameplayEffectLevel = 1, int32 Stacks = 1);

	/** Non blueprintcallable, safe to call on CDO/NonInstance abilities */
	TArray<FActiveGameplayEffectHandle> ApplyGameplayEffectToTarget(const FGameplayAbilitySpecHandle Handle, const FGameplayAbilityActorInfo* ActorInfo, const FGameplayAbilityActivationInfo ActivationInfo, const FGameplayAbilityTargetDataHandle& Target, TSubclassOf<UGameplayEffect> GameplayEffectClass, float GameplayEffectLevel, int32 Stacks = 1) const;

	/** Apply a previously created gameplay effect spec to a target */
	UFUNCTION(BlueprintCallable, Category = Ability, DisplayName = "ApplyGameplayEffectSpecToTarget", meta=(ScriptName = "ApplyGameplayEffectSpecToTarget"))
	TArray<FActiveGameplayEffectHandle> K2_ApplyGameplayEffectSpecToTarget(const FGameplayEffectSpecHandle EffectSpecHandle, FGameplayAbilityTargetDataHandle TargetData);

	TArray<FActiveGameplayEffectHandle> ApplyGameplayEffectSpecToTarget(const FGameplayAbilitySpecHandle AbilityHandle, const FGameplayAbilityActorInfo* ActorInfo, const FGameplayAbilityActivationInfo ActivationInfo, const FGameplayEffectSpecHandle SpecHandle, const FGameplayAbilityTargetDataHandle& TargetData) const;