Auto-Fire Projectile

changing default FPS template weapon to shoot full auto

As of UE5 use of the PlayerInputComponent for registering input has been replaced by the EnhancedInputComponent.

Projectile

Luckily the First Person template comes with a projectile, however it's currently semi-auto and we want full-auto glory.

Full-Auto

The idea here will be when the user presses the fire input we start a timer which executes Fire() every X seconds on a timer, and stops once the fire input is released.

Input Binding

Add two new InputActions and bind them to input events and callbacks

// TP_WeaponComponent.h

UPROPERTY(EditAnywhere, BlueprintReadOnly, Category=Input, meta=(AllowPrivateAccess = "true"))
class UInputAction* StartFireAction;

UPROPERTY(EditAnywhere, BlueprintReadOnly, Category=Input, meta=(AllowPrivateAccess = "true"))
class UInputAction* EndFireAction;

.cpp

// TP_WeaponComponent.cpp

void UTP_WeaponComponent::AttachWeapon(AGlooCannonCharacter* TargetCharacter)
{
    //...
    // old
    EnhancedInputComponent->BindAction(FireAction, ETriggerEvent::Triggered, this, &UTP_WeaponComponent::Fire);

    // new
    EnhancedInputComponent->BindAction(StartFireAction, ETriggerEvent::Triggered, this, &UTP_WeaponComponent::StartFire);
    EnhancedInputComponent->BindAction(EndFireAction, ETriggerEvent::Triggered, this, &UTP_WeaponComponent::EndFire);
    //...
}

Notice the difference from UE4 where we would have used a single action with two different input events (IE_Pressed and IE_Released) versus UE5 where now each action uses the same Triggered event (for more details UE docs here)

Implement Callback Functions

// TP_WeaponComponent.h

UFUNCTION(BlueprintCallable, Category="Weapon")
void StartFire();

UFUNCTION(BlueprintCallable, Category="Weapon")
void EndFire();

UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = Gameplay)
float BulletsPerMinute = 450;

float TimeBetweenShots;
FTimerHandle TimerHandle_BetweenShots;

.cpp

// TP_WeaponComponent.h

UTP_WeaponComponent::UTP_WeaponComponent()
{
	//...
	TimeBetweenShots = 60.f / BulletsPerMinute;
}

void UTP_WeaponComponent::StartFire()
{
	const float intialDelay = FMath::Max(TimeBetweenShots - GetWorld()->TimeSeconds, 0.f);

	if (UWorld* myWorld = GetWorld())
	{
		myWorld->GetTimerManager().SetTimer(TimerHandle_BetweenShots, this, &UTP_WeaponComponent::Fire, TimeBetweenShots, true, intialDelay);
	}
}

void UTP_WeaponComponent::EndFire()
{
	if (UWorld* myWorld = GetWorld())
	{
		myWorld->GetTimerManager().ClearTimer(TimerHandle_BetweenShots);
	}
}