Gas Cooldown Effect

I dont't want to create Cooldown effect for every Ability. So I want to find a way to create a Cooldown effect for all spells. To dynamically create a Cooldown effect for all spells. But finilly I found we can't do that. I writon a article about this.

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UGameplayAbility

Some related code in UGameplayAbility.cpp. At the beginning, I think we can simply override GetCooldownGameplayEffect to return my own Cooldown GE.

void UGameplayAbility::ApplyCooldown(const FGameplayAbilitySpecHandle Handle, const FGameplayAbilityActorInfo* ActorInfo, const FGameplayAbilityActivationInfo ActivationInfo) const
{
    UGameplayEffect* CooldownGE = GetCooldownGameplayEffect();
    if (CooldownGE)
    {
        ApplyGameplayEffectToOwner(Handle, ActorInfo, ActivationInfo, CooldownGE, GetAbilityLevel(Handle, ActorInfo));
    }
}

UGameplayEffect* UGameplayAbility::GetCooldownGameplayEffect() const
{
    if ( CooldownGameplayEffectClass )
    {
        return CooldownGameplayEffectClass->GetDefaultObject<UGameplayEffect>();
    }
    else
    {
        return nullptr;
    }
}

so I just override GetCooldownGameplayEffect to return my own Cooldown GE.

UGameplayEffect* UAuraGameplayAbility::GetCooldownGameplayEffect() const
{
    const auto Test =Super::GetCooldownGameplayEffect();
    // has value, using the simple cooldown config.
    if (CooldownDuration != -1.f && CooldownTag.IsValid())
    {
        if (CooldownGE) return CooldownGE;

        CooldownGE = NewObject<UGameplayEffect>();

        CooldownGE->DurationPolicy =EGameplayEffectDurationType::HasDuration;

        UTargetTagsGameplayEffectComponent& TargetTagsComponent = CooldownGE->FindOrAddComponent<UTargetTagsGameplayEffectComponent>();

        CooldownGE->DurationMagnitude = FGameplayEffectModifierMagnitude(FScalableFloat(CooldownDuration));
        CooldownGE->Period = 1.f;
        FInheritedTagContainer TagContainerMods;
        TagContainerMods.AddTag(CooldownTag);
        TargetTagsComponent.SetAndApplyTargetTagChanges(TagContainerMods);
        return CooldownGE;
    }
    return Test;
}

But it doesn't work. So I dive into the source code.

FActiveGameplayEffectHandle UGameplayAbility::ApplyGameplayEffectToOwner(const FGameplayAbilitySpecHandle Handle, const FGameplayAbilityActorInfo* ActorInfo, const FGameplayAbilityActivationInfo ActivationInfo, const UGameplayEffect* GameplayEffect, float GameplayEffectLevel, int32 Stacks) const
{
    if (GameplayEffect && (HasAuthorityOrPredictionKey(ActorInfo, &ActivationInfo)))
    {
        FGameplayEffectSpecHandle SpecHandle = MakeOutgoingGameplayEffectSpec(Handle, ActorInfo, ActivationInfo, GameplayEffect->GetClass(), GameplayEffectLevel);
        if (SpecHandle.IsValid())
        {
            SpecHandle.Data->SetStackCount(Stacks);
            return ApplyGameplayEffectSpecToOwner(Handle, ActorInfo, ActivationInfo, SpecHandle);
        }
    }

    // We cannot apply GameplayEffects in this context. Return an empty handle.
    return FActiveGameplayEffectHandle();
}

In ApplyGameplayEffectToOwner, we can see that it will call MakeOutgoingGameplayEffectSpec to create a FGameplayEffectSpecHandle. And then call ApplyGameplayEffectSpecToOwner to apply the FGameplayEffectSpecHandle. But it not using my own Cooldown GE.GameplayEffect->GetClass(), it will get the CooldownGameplayEffectClass from UGameplayAbility, its the class deflault object.

here is the code show how to create a FGameplayEffectSpecHandle:

FGameplayEffectSpecHandle UAbilitySystemComponent::MakeOutgoingSpec(TSubclassOf<UGameplayEffect> GameplayEffectClass, float Level, FGameplayEffectContextHandle Context) const
{
    SCOPE_CYCLE_COUNTER(STAT_GetOutgoingSpec);
    if (Context.IsValid() == false)
    {
        Context = MakeEffectContext();
    }

    if (GameplayEffectClass)
    {
        UGameplayEffect* GameplayEffect = GameplayEffectClass->GetDefaultObject<UGameplayEffect>();

        FGameplayEffectSpec* NewSpec = new FGameplayEffectSpec(GameplayEffect, Context, Level);
        return FGameplayEffectSpecHandle(NewSpec);
    }

    return FGameplayEffectSpecHandle(nullptr);
}

UGameplayEffect* GameplayEffect = GameplayEffectClass->GetDefaultObject<UGameplayEffect>(); that is the problem.

My Opinion

I think The reason for this design is...

• Performance optimization: Using GetDefaultObject can help avoid frequently creating and destroying objects, especially when they are used a lot.
• Data consistency: Make sure all GameplayEffects of the same type use the same base configuration.
• Blueprint compatibility: This design makes it easy to create and configure GameplayEffects in Blueprints.
• Network synchronization: Using predefined classes makes it easier to sync effects in multiplayer games.
• Serializability: Predefined classes are easier to serialize and deserialize, which is important for saving game states.

if you know another way to create a Cooldown effect for all spells, please tell me. I will be very grateful.

Other Solution

• auto create cooldown effect

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