I Am Stuck On Making A Blueprint class that is derived from a C++ class

UnrealEngine · February 7, 2022, 10:33am

I am on ToonTanks. I made a blueprint class called BP_PawnTank that is derived from BasePawn. There is a problem, it doesn’t show CapsuleComp.
Look at this:
BasePawn.h:

// Fill out your copyright notice in the Description page of Project Settings.

#pragma once

#include "CoreMinimal.h"
#include "GameFramework/Pawn.h"
#include "BasePawn.generated.h"

UCLASS()
class TOONTANKS_API ABasePawn : public APawn
{
	GENERATED_BODY()

public:
	// Sets default values for this pawn's properties
	ABasePawn();

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

private:
	UPROPERTY()
	class UCapsuleComponent* CapsuleComp;
	UPROPERTY()
	UStaticMeshComponent* BaseMesh;
	UPROPERTY()
	UStaticMeshComponent* TurretMesh;
	UPROPERTY()
	USceneComponent* ProjectileSpawnPoint;

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

	// Called to bind functionality to input
	virtual void SetupPlayerInputComponent(class UInputComponent* PlayerInputComponent) override;

};

BasePawn.cpp:

// Fill out your copyright notice in the Description page of Project Settings.

#include "BasePawn.h"
#include "Components/CapsuleComponent.h"

// Sets default values
ABasePawn::ABasePawn()
{
 	// Set this pawn to call Tick() every frame.  You can turn this off to improve performance if you don't need it.
	PrimaryActorTick.bCanEverTick = true;

}

// Called when the game starts or when spawned
void ABasePawn::BeginPlay()
{
	Super::BeginPlay();

	CapsuleComp = CreateDefaultSubobject<UCapsuleComponent>(TEXT("Capsule Collider"));
	RootComponent = CapsuleComp;

	BaseMesh = CreateDefaultSubobject<UStaticMeshComponent>(TEXT("Base Mesh"));
	BaseMesh->SetupAttachment(CapsuleComp);

	TurretMesh = CreateDefaultSubobject<UStaticMeshComponent>(TEXT("Turret Mesh"));
	TurretMesh->SetupAttachment(BaseMesh);
	
	ProjectileSpawnPoint = CreateDefaultSubobject<USceneComponent>(TEXT("Projectile Spawn Point"));
	ProjectileSpawnPoint->SetupAttachment(TurretMesh);
}

// Called every frame
void ABasePawn::Tick(float DeltaTime)
{
	Super::Tick(DeltaTime);

}

// Called to bind functionality to input
void ABasePawn::SetupPlayerInputComponent(UInputComponent* PlayerInputComponent)
{
	Super::SetupPlayerInputComponent(PlayerInputComponent);

}

See:

How do I fix this problem.
When I try to make a new capsule component called CapsuleComp, it says there is already one. I think there is already a capsule component.
I think the problem is not because the inheritance is not correct, I think it’s because the BP_PawnTank is hiding the components.
Can you tell me how to fix the problem?

Morderkainer · February 7, 2022, 1:09pm

I think it is because the UPROPERTY.
Instead of this:

	UPROPERTY()
	class UCapsuleComponent* CapsuleComp;
	UPROPERTY()
	UStaticMeshComponent* BaseMesh;
	UPROPERTY()
	UStaticMeshComponent* TurretMesh;
	UPROPERTY()
	USceneComponent* ProjectileSpawnPoint;

It should be like this:

	UPROPERTY(BlueprintReadOnly, VisibleAnywhere, meta = (AllowPrivateAccess = true))
	class UCapsuleComponent* CapsuleComp;

	UPROPERTY(BlueprintReadOnly, VisibleAnywhere, meta = (AllowPrivateAccess = true))
	UStaticMeshComponent* BaseMesh;
	
	UPROPERTY(BlueprintReadOnly, VisibleAnywhere, meta = (AllowPrivateAccess = true))
	UStaticMeshComponent* TurretMesh;

	UPROPERTY(BlueprintReadOnly, VisibleAnywhere, meta = (AllowPrivateAccess = true))
	USceneComponent* ProjectileSpawnPoint;

If you don’t specify it to be visible, it will not appear in the editor.

UnrealEngine · February 8, 2022, 5:53am

But Stephen(the instructor) used:

Morderkainer:

	UPROPERTY()
	class UCapsuleComponent* CapsuleComp;
	UPROPERTY()
	UStaticMeshComponent* BaseMesh;
	UPROPERTY()
	UStaticMeshComponent* TurretMesh;
	UPROPERTY()
	USceneComponent* ProjectileSpawnPoint;

instead of:

Morderkainer:

	UPROPERTY(BlueprintReadOnly, VisibleAnywhere, meta = (AllowPrivateAccess = true))
	class UCapsuleComponent* CapsuleComp;

	UPROPERTY(BlueprintReadOnly, VisibleAnywhere, meta = (AllowPrivateAccess = true))
	UStaticMeshComponent* BaseMesh;
	
	UPROPERTY(BlueprintReadOnly, VisibleAnywhere, meta = (AllowPrivateAccess = true))
	UStaticMeshComponent* TurretMesh;

	UPROPERTY(BlueprintReadOnly, VisibleAnywhere, meta = (AllowPrivateAccess = true))
	USceneComponent* ProjectileSpawnPoint;

How did it still work for him?
He’s just using UPROPERTY():
See:
https://www.udemy.com/course/unrealcourse/learn/lecture/28496448#overview
Go to 5:10. And see that he doesn’t add the parameters inside UPROPERTY().

Is it actually required to use that. I don’t know what meta = (AllowPrivateAccess = true) means.

UnrealEngine · February 8, 2022, 10:47am

It doesn’t work:

How do I do this then?

Morderkainer · February 8, 2022, 11:32am

Sorry, my mistake, I did a quick look and that is the first thing I saw. Now, after taking more time to check your code, I know exactly where is the problem.

In the .cpp file, you are creating the components inside BeginPlay, it has to be done inside the constructor ABasePawn::ABasePawn()
{
}

UnrealEngine · February 8, 2022, 11:33am

I am stuck!
Look:
BasePawn.h:

// Fill out your copyright notice in the Description page of Project Settings.

#pragma once

#include "CoreMinimal.h"
#include "GameFramework/Pawn.h"
#include "BasePawn.generated.h"

UCLASS()
class TOONTANKS_API ABasePawn : public APawn
{
	GENERATED_BODY()

public:
	// Sets default values for this pawn's properties
	ABasePawn();

	UPROPERTY(EditAnywhere, BlueprintReadWrite)
	int32 Number = 1;

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

private:
	UPROPERTY(VisibleAnywhere, BlueprintReadWrite, Category = "Components", meta = (AllowPrivateAccess = "true"))
	class UCapsuleComponent* CapsuleComp;
	UPROPERTY(VisibleAnywhere, BlueprintReadWrite, Category = "Components", meta = (AllowPrivateAccess = "true"))
	UStaticMeshComponent* BaseMesh;
	UPROPERTY(VisibleAnywhere, BlueprintReadWrite, Category = "Components", meta = (AllowPrivateAccess = "true"))
	UStaticMeshComponent* TurretMesh;
	UPROPERTY(VisibleAnywhere, BlueprintReadWrite, Category = "Components", meta = (AllowPrivateAccess = "true"))
	USceneComponent* ProjectileSpawnPoint;

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

	// Called to bind functionality to input
	virtual void SetupPlayerInputComponent(class UInputComponent* PlayerInputComponent) override;

};

BasePawn.cpp:

// Fill out your copyright notice in the Description page of Project Settings.

#include "BasePawn.h"

#include "Components/CapsuleComponent.h"

// Sets default values

ABasePawn::ABasePawn()

{

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

    PrimaryActorTick.bCanEverTick = true;

}

// Called when the game starts or when spawned

void ABasePawn::BeginPlay()

{

    Super::BeginPlay();

    CapsuleComp = CreateDefaultSubobject<UCapsuleComponent>(TEXT("Capsule Collider"));

    RootComponent = CapsuleComp;

    BaseMesh = CreateDefaultSubobject<UStaticMeshComponent>(TEXT("Base Mesh"));

    BaseMesh->SetupAttachment(CapsuleComp);

    TurretMesh = CreateDefaultSubobject<UStaticMeshComponent>(TEXT("Turret Mesh"));

    TurretMesh->SetupAttachment(BaseMesh);

   

    ProjectileSpawnPoint = CreateDefaultSubobject<USceneComponent>(TEXT("Projectile Spawn Point"));

    ProjectileSpawnPoint->SetupAttachment(TurretMesh);

}

// Called every frame

void ABasePawn::Tick(float DeltaTime)

{

    Super::Tick(DeltaTime);

}

// Called to bind functionality to input

void ABasePawn::SetupPlayerInputComponent(UInputComponent* PlayerInputComponent)

{

    Super::SetupPlayerInputComponent(PlayerInputComponent);

}

This is bad.
Look:

The problem is that it doesn’t have the components in the components tab.

UnrealEngine · February 8, 2022, 11:37am

I am severely stuck. The instructor is already adding static meshes to the BaseMesh component. While I haven’t even got the component on the components tab. I can’t edit the BaseMesh in the variables tab.

UnrealEngine · February 8, 2022, 11:37am

What do I do?

UnrealEngine · February 8, 2022, 11:38am

Oh, I didn’t see your post. Okay let me try.

Morderkainer · February 8, 2022, 11:39am

Don’t panic, already told you in my previous post, you are creating the components inside beginplay, when it has to be done inside the constructor, just change this:

// Fill out your copyright notice in the Description page of Project Settings.

#include "BasePawn.h"
#include "Components/CapsuleComponent.h"

// Sets default values
ABasePawn::ABasePawn()
{
 	// Set this pawn to call Tick() every frame.  You can turn this off to improve performance if you don't need it.
	PrimaryActorTick.bCanEverTick = true;

}

// Called when the game starts or when spawned
void ABasePawn::BeginPlay()
{
	Super::BeginPlay();

	CapsuleComp = CreateDefaultSubobject<UCapsuleComponent>(TEXT("Capsule Collider"));
	RootComponent = CapsuleComp;

	BaseMesh = CreateDefaultSubobject<UStaticMeshComponent>(TEXT("Base Mesh"));
	BaseMesh->SetupAttachment(CapsuleComp);

	TurretMesh = CreateDefaultSubobject<UStaticMeshComponent>(TEXT("Turret Mesh"));
	TurretMesh->SetupAttachment(BaseMesh);
	
	ProjectileSpawnPoint = CreateDefaultSubobject<USceneComponent>(TEXT("Projectile Spawn Point"));
	ProjectileSpawnPoint->SetupAttachment(TurretMesh);
}

// Called every frame
void ABasePawn::Tick(float DeltaTime)
{
	Super::Tick(DeltaTime);

}

// Called to bind functionality to input
void ABasePawn::SetupPlayerInputComponent(UInputComponent* PlayerInputComponent)
{
	Super::SetupPlayerInputComponent(PlayerInputComponent);

}

to this

// Fill out your copyright notice in the Description page of Project Settings.

#include "BasePawn.h"
#include "Components/CapsuleComponent.h"

// Sets default values
ABasePawn::ABasePawn()
{
 	// Set this pawn to call Tick() every frame.  You can turn this off to improve performance if you don't need it.
	PrimaryActorTick.bCanEverTick = true;


	CapsuleComp = CreateDefaultSubobject<UCapsuleComponent>(TEXT("Capsule Collider"));
	RootComponent = CapsuleComp;

	BaseMesh = CreateDefaultSubobject<UStaticMeshComponent>(TEXT("Base Mesh"));
	BaseMesh->SetupAttachment(CapsuleComp);

	TurretMesh = CreateDefaultSubobject<UStaticMeshComponent>(TEXT("Turret Mesh"));
	TurretMesh->SetupAttachment(BaseMesh);
	
	ProjectileSpawnPoint = CreateDefaultSubobject<USceneComponent>(TEXT("Projectile Spawn Point"));
	ProjectileSpawnPoint->SetupAttachment(TurretMesh);

}

// Called when the game starts or when spawned
void ABasePawn::BeginPlay()
{
	Super::BeginPlay();

}

// Called every frame
void ABasePawn::Tick(float DeltaTime)
{
	Super::Tick(DeltaTime);

}

// Called to bind functionality to input
void ABasePawn::SetupPlayerInputComponent(UInputComponent* PlayerInputComponent)
{
	Super::SetupPlayerInputComponent(PlayerInputComponent);

}

UnrealEngine · February 8, 2022, 11:40am

You got it!!! Now, I don’t have to have this worried feeling that I’m so behind and I can’t do anything.

system · February 9, 2022, 11:40am

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