undeclared identifier error

Development Programming & Scripting C++
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1

Hello Unreal Engine community,

I am currently working on a top-down shooter project, and I want my character to always rotate towards the mouse position. However, I am facing a compilation error: “CPP_Player”: undeclared identifier. I have tried various solutions, but the error persists. Here is the code for the CPP_PlayerController.cpp and CPP_PlayerController.h files:

CPP_PlayerController.cpp:

#include "CPP_PlayerController.h"
#include "CPP_Player.h"

ACPP_PlayerController::ACPP_PlayerController()
{
    PrimaryActorTick.bCanEverTick = true;
}

void ACPP_PlayerController::BeginPlay()
{
    Super::BeginPlay();

    ControlledPlayer = Cast<CPP_Player>(GetCharacter());
}

void ACPP_PlayerController::Tick(float DeltaTime)
{
    FVector MouseVector = GetMouseVector();

    // Get the character and calculate the direction vector from the character to the mouse position
    if (ControlledPlayer)
    {
        FVector DirectionVector = MouseVector - ControlledPlayer->GetActorLocation();
        DirectionVector.Z = 0.0f; // Ignore the Z-axis to only rotate on the XY plane

        // Rotate the character towards the mouse position
        if (DirectionVector.SizeSquared() > 0.0f) // Make sure the direction vector is not zero
        {
            FRotator TargetRotation = DirectionVector.Rotation();
            ControlledPlayer->SetActorRotation(TargetRotation);
        }
    }
    FString MouseVectorString = GetMouseVector().ToString();

    // Print the vector in a debug message
    GEngine->AddOnScreenDebugMessage(-1, 15.0f, FColor::Yellow, FString::Printf(TEXT("Mouse position: %s"), *MouseVectorString));
}

FVector ACPP_PlayerController::GetMouseVector()
{
    // Get the current mouse position
    FVector2D MousePosition;
    GetMousePosition(MousePosition.X, MousePosition.Y);

    // Get the world location of the mouse cursor
    FVector MouseLocation, MouseDirection;
    DeprojectScreenPositionToWorld(MousePosition.X, MousePosition.Y, MouseLocation, MouseDirection);

    // Store the mouse location in a vector and return it
    return FVector(MouseLocation.X, MouseLocation.Y, MouseLocation.Z);
}

CPP_PlayerController.h:

#pragma once

#include "CoreMinimal.h"
#include "GameFramework/PlayerController.h"
#include "CPP_Player.h"
#include "CPP_PlayerController.generated.h"


/**
 * 
 */


class CPP_Player;


UCLASS()
class TOPDOWNLEVELSHOOTER_API ACPP_PlayerController : public APlayerController
{
	GENERATED_BODY()

protected:
	CPP_Player* ControlledPlayer;
	// Called when the game starts or when spawned
	virtual void BeginPlay() override;
public:
	ACPP_PlayerController();
	virtual void Tick(float DeltaTime) override;
public:
	FVector GetMouseVector();
	
};
2

Hi Nil_syo,
Try replacing the line in CPP_PlayerController.h:
from “class CPP_Player” to “class ACPP_Player”.

1 Like
3

Oh, great! That works! I just started using Unreal Engine, and I forgot about the importance of adding a forward declaration before a class. Thank you so much for your help!

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