Damage System | Shooter Tutorial

Generic, extendable and easy to use damage system for any game.

Damage System is part of Game Dev Tools Plugin.

Features

Created using UE4 SubSystem,
Damage Data can be extended and modified during damage,
Helper functions: ModifyDamage, MultiplyDamage, GetBackstabDot, GetDotToTarget, GetCreatedTime,
Using interface to deal damage,
Works with Health Component

Documentation

Example Map

Example map can be found here:
\Plugins\GDMegaPack\Content\Health\Maps\Showcase_GDHealthAndDamage.umap

Applying Damage

To Apply damage use ApplyDamage function from DamageSubsystem. You need to create DamagaData and pass it. Apply damage will call Damage Receiver Interface.

To apply damage it in C++:

// get game instance 
UGameInstance* GameInstance = GetGameInstance(GetWorld()->GetGameInstance());

// get damage subsystem from game instance 
UGDDamageSystem* DamageSystem = GameInstance->GetSubsystem&lt;UGDDamageSystem>();

// create new damage data
UGDDamageData* DamageData = UGDMegaPackFunctionLibrary::CreateGDDamageData(this, UGDDamageData::StaticClass());

// apply damage to target using new damage data
DamageSystem->ApplyDamage(DamageData, Victim);

// get game instance

UGameInstance* GameInstance = GetGameInstance(GetWorld()->GetGameInstance());

// get damage subsystem from game instance

UGDDamageSystem* DamageSystem = GameInstance->GetSubsystem<UGDDamageSystem>();

// create new damage data

UGDDamageData* DamageData = UGDMegaPackFunctionLibrary::CreateGDDamageData(this, UGDDamageData::StaticClass());

// apply damage to target using new damage data

DamageSystem->ApplyDamage(DamageData, Victim);

Receiving Damage

To receive damage Actor need to implement GDDamageReceiver Interface.

This can be done in Blueprints in Class Settings:

Then you will have two functions. CanTakeDamage and TakeDamage:

Normally Apply Damage do nothing you need to plug in your health system. You can use Health Component from Plugin like here:

To receive damage in C++ you need to add interface to your Actor and override interface functions:

UCLASS()
class GDMEGAPACKPROJECT_API AActorWithDamageReceiverInterface : public AActor, public IGDDamageReceiverInterface
{
	GENERATED_BODY()
	
public:	
	// Sets default values for this actor's properties
	AActorWithDamageReceiverInterface();

	bool TakeGDDamage_Implementation(const UGDDamageData* DamageData) override { return true; }
	bool CanTakeGDDamage_Implementation(const UGDDamageData* DamageData) override { return true; }
}

UCLASS()

class GDMEGAPACKPROJECT_API AActorWithDamageReceiverInterface : public AActor, public IGDDamageReceiverInterface

{

GENERATED_BODY()

public:

// Sets default values for this actor's properties

AActorWithDamageReceiverInterface();

bool TakeGDDamage_Implementation(const UGDDamageData* DamageData) override { return true; }

bool CanTakeGDDamage_Implementation(const UGDDamageData* DamageData) override { return true; }

}

FAQ

Why not use UE4 Apply Damage?

Default UE4 Damage implementation have two problems:

You can’t extend damage structure in Blueprints. For example if you want to use your data you need to create your own functions to deal damage with your custom structure ignoring UE4 Damage implementation,
Damage informations can’t be changed during runtime as it’s const,

Damage System can be easyly extendable: create your own Damage Data, override ApplyDamage functions and use interface to receive damage.