How to make a TMap of UClass* and a method in that class?

[Aejjee]

I want to make a TMap of UClass pointers as the keys, and a function to call as the values. This would be extremely useful in pretty much any game, for example having generalized enemy types with damage health functions, so I can’t imagine this has never been done but I haven’t found any forum posts on it. What I have right now is this:

TMap<UClass*, void (TSubclassOf<AActor*>::*)(float)> badGuyTypes;

TTuple<UClass*, void (TSubclassOf<AActor*>::*)(float)> type1 = TTuple<UClass*, void (TSubclassOf<AActor*>::*)(float)>(AbadGuyActor::StaticClass(), &AbadGuyActor::damageHealth);

badGuyTypes.Add(type1);

I get an error saying that there is no constructor to make this because
void (TSubclassOf<AActor*>::*)(float) does not equal &AbadGuyActor::damageHealth. How do I just get a function pointer to a function in an unknown subclass of AActor?

bumping this

[RecourseDesign]

Hi Aejjee,

If I’m understanding you correctly - I think you would be better off having a “BadGuy” base class and SubClass off that for each of your other types, giving each of those it’s own derived “damgeHealth” function.

Then you could just call those functions from a list of all actors subclassed from “BadGuy” - it calls the correct function even when you’re just storing it as a BadGuy - as long as you constructed it as the specific type of SubClassed BadGuy.

[Aejjee]

What’s the difference between having the bad guys as subclasses of AActor? Wouldn’t it just be the same sitiuation where I’d have to say TSubclassOf<BadGuy*>::* but then each individual function pointer would just be like &badGuy1::damageHealth?

That seems like the same situation where it won’t like that badGuy1 isn’t directly equivalent to TSubclassOf<BadGuy*>. I likely misunderstood your solution could you explain it more?

[RecourseDesign]

I was meaning instead of doing any of that.

I’m picturing you currently doing something like badGuyTypes[mybadGuyActor::GetStaticClass()].damageHealth

If you have BadGuy SubClassed from Actor with a function called “GetDamageHealth” - then MyBadGuy1 SubClassed from BadGuy, override that “GetDamageHealth” and return what you want there.

Then you can simply do:

mybadGuyActor->GetDamageHealth()

But I may not be grasping exactly what you’re after…

[Aejjee]

I think I’m following what you’re saying and that would work but I’m not quite sure how to do that. I created a new class derived from AActor called badGuyBase, and in badGuyBase.h I defined:

UFUNCTION()
	void DamageHealth(float value);

I also wrote an empty definition of it in badGuyBase.cpp.

Then in badGuyActor.h I switched it to be derived from badGuyBase (I think) by doing:

class YOCRAZYSTORYHERE_API AbadGuyActor : public AbadGuyBase

Then I tried overriding DamageHealth() in AbadGuyActor.h by doing:

virtual void DamageHealth(float value) override;

but it gave me the error:

member function declared with ‘override’ does not override a base class member

How exactly do I make badGuyActor derived from badGuyBase and then override DamageHealth()?

[RecourseDesign]

That’s almost it, in the baseclass header, declare it as virtual:

UFUNCTION()
virtual void DamageHealth(float value);

but wouldn’t it be:

UFUNCTION()
virtual float DamageHealth();

to return the amount of damage?

[Aejjee]

Sweet that worked! No its meant to be like you call the damage health function on a bad guy for the amount of health the bad guy is damaged. Thank you for your help this was a much more elegant solution!