Delegates without reference to object?

Development Programming & Scripting C++
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1

Hi all,

I’ve only started working with delegates recently, so I’m not sure if I understand the full extent of their uses. Anyways, usually when I need to bind a function to a delegate, I need a reference to the object. For example, if I wanted my gamemode to do something when any enemy is killed, I have to have a reference to the enemy to bind to the delegate.

Enemy->OnKilled.AddDynamic(this, &AGamemode::OnEnemyKilled)

I don’t know if my wording makes sense here, but is there a way to bind to a delegate without a reference to an existing instance? I want OnEnemyKilled to be called when any enemy dies without having to make sure my bind gets added anytime an enemy spawns.

Something like this

void AGamemode::BeginPlay() {

    AEnemy::OnKilled.AddDynamic(this, &AGamemode::OnEnemyKilled);

}
2

You could reverse the situation and bind all enemies to a delegate inside of an enemy manager, that would do actions according with their deaths (add points, xp etc)

3

The OnKilled delegate is called by the object, unless you declare it static static FOnKilled OnKilled, then you need 1 parameter on the delegate to tell which enemy is killed

 DECLARE_DELEGATE_OneParam(FOnKilled, AEnemy*);

public:
static FOnKilled OnKilled;

when it called by an enemy

OnKilled.Execute(this);
4

This seems to be what I might want. How do you bind to it from another class though (Like how would I execute AGameMode::TestFunc(AEnemy* Enemy) )?

EDIT: Doesn’t compile either

BaseCharacter.cpp.obj : error LNK2001: unresolved external symbol "public: static class TDelegate<void __cdecl(class ABaseCharacter *),struct FDefaultDelegateUserPolicy> ABaseCharacter::TestDelegate" (?TestDelegate@ABaseCharacter@@2V?$TDelegate@$$A6AXPEAVABaseCharacter@@@ZUFDefaultDelegateUserPolicy@@@@A)
D:\Program Files\Epic Games\Unreal Projects\HaloFloodFanGame01 5.2\Binaries\Win64\UnrealEditor-HaloFloodFanGame01.patch_4.exe : fatal error LNK1120: 1 unresolved externals
5

I am sorry, I just tried it and it seems delegate cannot be declared as static, then you need it referenced to an object.