AddDynamic is not working

Development Programming & Scripting
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1

I’m trying to bind my function to a delegate using AddDynamic. However, I keep getting a ‘error C2664’ that states:

no instance of function template "FComponentHitSignature::__Internal_AddDynamic" matches the argument list -- C/C++ (304) [Ln 29, Col 33]

argument types are: (AProjectile *, void (AProjectile::*)(UPrimitiveComponent *HitComp, AActor *OtherActor, UPrimitiveComponent *OtherComp, FVector NormalImpulse, FHitResult &Hit), FName)

object type is: FComponentHitSignature

I’ve tried restarting the project, rebuilding the code while project is closed. Checked to see if the delegate is a UFUNCTION(). I’m not sure why I’m getting this error.

Has anyone run into this issue before?

Here is my header & CPP file:

Header


#include "CoreMinimal.h"
#include "GameFramework/Actor.h"
#include "GameFramework/ProjectileMovementComponent.h"
#include "Projectile.generated.h"

UCLASS()
class TOONTANKS_API AProjectile : public AActor
{
	GENERATED_BODY()
	
public:	
	// Sets default values for this actor's properties
	AProjectile();

protected:
	// Called when the game starts or when spawned
	virtual void BeginPlay() override;

public:	
	// Called every frame
	virtual void Tick(float DeltaTime) override;


private:
	UPROPERTY(EditDefaultsOnly, BlueprintReadOnly, Category = "Combat", meta = (AllowPrivateAccess = "true"))
	UStaticMeshComponent* ProjectileMesh;

	UPROPERTY(VisibleAnywhere, Category = "Movement")
	class UProjectileMovementComponent* ProjectileMovement;

	UPROPERTY(EditAnywhere, Category = "Movement")
	float InitialSpeed;

	UPROPERTY(EditAnywhere, Category = "Movement")
	float MaxSpeed;


	// Callback function for a hit event
	// This type of callback needs certain parameters. First, a UPrimitiveComponent* HitComp (This will handle the collision)
	// Next will be AActor* OtherActor to represent the object we collide with
	// Next will be another UPrimitiveComponent* OtherComp. This is the other component that was it
	// Next will be a FVector NormalImpulse to simulate physics and apply an impulse to a collision (directiohn & Maginitude)
	// Finally we will need a const FHitResult& Hit. This will return information about the hit

	// Because this is a delegate for a hit funciton, it has to be a UFUNCTION() for it to work
	UFUNCTION()
	void OnHit(UPrimitiveComponent* HitComp, AActor* OtherActor, UPrimitiveComponent* OtherComp, FVector NormalImpulse, FHitResult& Hit);

};

CPP

#include "Projectile.h"

#include "Components/StaticMeshComponent.h"

// Sets default values

AProjectile::AProjectile()

{

// Set this actor to call Tick() every frame. You can turn this off to improve performance if you don't need it.

PrimaryActorTick.bCanEverTick = true;

// Creating Constructor so that I can edit and see this in Blueprint

ProjectileMesh = CreateDefaultSubobject<UStaticMeshComponent>(TEXT("Projectile Mesh"));

RootComponent = ProjectileMesh;

ProjectileMovement = CreateDefaultSubobject<UProjectileMovementComponent>(TEXT("Projectile Movement Component"));

ProjectileMovement->MaxSpeed = 1300.f;

ProjectileMovement->InitialSpeed = 1300.f;

}

// Called when the game starts or when spawned

void AProjectile::BeginPlay()

{

Super::BeginPlay();

// Binding the OnHit() function to our delegate

// Doing this in the constructor can cause issues (e.g. not binding the function to the delegate)

ProjectileMesh->OnComponentHit.AddDynamic(this, &AProjectile::OnHit);

}

// Called every frame

void AProjectile::Tick(float DeltaTime)

{

Super::Tick(DeltaTime);

}

// Callback Function that is defining the Hit Event

void AProjectile::OnHit(UPrimitiveComponent* HitComp, AActor* OtherActor, UPrimitiveComponent* OtherComp, FVector NormalImpulse, FHitResult& Hit)

{

UE_LOG(LogTemp, Warning, TEXT("Hit"));

}
2

It’s failing because the parameter list in your function OnHit doesn’t exactly match the signature of FComponentHitSignature.

You need to make the FHitResult a const reference, so your signature should be

	UFUNCTION()
	void OnHit(UPrimitiveComponent* HitComp, AActor* OtherActor, UPrimitiveComponent* OtherComp, FVector NormalImpulse, const FHitResult& Hit);

You can see the signature declaration yourself on line 184 in PrimitiveComponent.h:

DECLARE_DYNAMIC_MULTICAST_SPARSE_DELEGATE_FiveParams( FComponentHitSignature, UPrimitiveComponent, OnComponentHit, UPrimitiveComponent*, HitComponent, AActor*, OtherActor, UPrimitiveComponent*, OtherComp, FVector, NormalImpulse, const FHitResult&, Hit );
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