WARNING

This post base on Aura GAS Course

In the Aura Course, we have to manually input all the RPG Attribute Items into the DataAsset, which is pretty boring and repetitive. So, I believe we can generate default values based on the existing information, eliminating the need for manual input and achieving semi-automation.

TLDR

• Utilize FindFieldChecked<FProperty>(UAuraAttributeSet::StaticClass(), AttributeName) to save FGameplayAttribute in DataAsset
• Use GetDerivedClasses to obtain all subclasses of UGameplayAbility.

Auto Collect All Attributes

• Utilize UGameplayTagsManager.RequestGameplayTagChildren to locate all the Sub Tags.
• Utilize FindFieldChecked<FProperty>(UAuraAttributeSet::StaticClass(), AttributeName) to retrieve the AttributeGetter and store it in DataAssets for future use.

    UAuraAttributeDataAsset::UAuraAttributeDataAsset()
{
	// init default attributes from tag manager with parent tag is "Attribute.*"
	const UGameplayTagsManager& Manager = UGameplayTagsManager::Get();
	const FGameplayTagContainer PrimaryTags = Manager.RequestGameplayTagChildren(FGameplayTag::RequestGameplayTag("Attribute.Primary", false));
	const FGameplayTagContainer SecondaryTags = Manager.RequestGameplayTagChildren(FGameplayTag::RequestGameplayTag("Attribute.Secondary", false));
	const FGameplayTagContainer ResistanceTags = Manager.RequestGameplayTagChildren(FGameplayTag::RequestGameplayTag("Attribute.Resistance", false));
	AddDefaultAttributeInfos(PrimaryTags);
	AddDefaultAttributeInfos(SecondaryTags);
	AddDefaultAttributeInfos(ResistanceTags, true);
}

void UAuraAttributeDataAsset::AddDefaultAttributeInfos(const FGameplayTagContainer& Tags, const bool bIsResistance)
{
	for (const FGameplayTag& Tag : Tags)
	{
		FAttributeInfo Attribute;
		Attribute.AttributeTag = Tag;
		// split tag name by '.' and get the last part, tag example: "Attribute.Primary.Intelligence", we only need "Intelligence"
		FString TagName = Tag.ToString();
		int32 LastDotIndex;
		if (TagName.FindLastChar('.', LastDotIndex))
		{
			TagName = TagName.Mid(LastDotIndex + 1);
		}
		Attribute.AttributeName = FText::FromString(bIsResistance ? TagName + " Resistance" : TagName);
#if WITH_EDITORONLY_DATA
		Attribute.AttributeDescription = FText::FromString(UGameplayTagsManager::Get().FindTagNode(AuraGameplayTags::Attribute_Primary_Intelligence).Get()->GetDevComment());
#endif
		Attribute.AttributeValue = 0.f;
		const FName AttributeName = bIsResistance ? FName(*("Resistance" + TagName)) : FName(*TagName);
		Attribute.AttributeGetter = FindFieldChecked<FProperty>(UAuraAttributeSet::StaticClass(), AttributeName);
		Attributes.Add(Attribute);
	}
}

Auto Collect All Offensive Abilities

In the Aura Course, all the offensive abilities have an Input Tag, so we can leverage this to identify all offensive spells.

• Use GetDerivedClasses to obtain all subclasses of UGameplayAbility.

UAuraAbilitiesDataAsset::UAuraAbilitiesDataAsset()
{
	TArray<UClass*> AbilityClasses;
	GetDerivedClasses(UAuraGameplayAbility::StaticClass(), AbilityClasses, true);
	for (UClass* AbilityClass : AbilityClasses)
	{
		UAuraGameplayAbility* Ability = Cast<UAuraGameplayAbility>(AbilityClass->GetDefaultObject());
		// has a press key tag means it's a player triggered spell
		if (Ability && Ability->PlayerKeyPressTag.IsValid())
		{
			FAbilityInfo Info;
			Info.InputTag = Ability->PlayerKeyPressTag;
			if (Ability->AbilityTags.Num() > 0)
			{
				Info.AbilityTag = Ability->AbilityTags.First();
			}
			Info.Ability = AbilityClass;
			AbilityInformation.Add(Info);
		}
	}
}