Can not compile because my code says that "PhysicsHandle" is undeclaired

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#1

for some reason when im trying to compile my code for the “crypt raider” tutorial, it is telling me that “PhysicsHandle” is an undeclaired identifier, however my header file already includes “PhysicsEngine/PhysicsHandleComponent.h”

here’s both the cpp and header files for

Grabber.h:

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

#pragma once

#include "CoreMinimal.h"
#include "Components/SceneComponent.h"
#include "PhysicsEngine/PhysicsHandleComponent.h"
#include "Grabber.generated.h"


UCLASS( ClassGroup=(Custom), meta=(BlueprintSpawnableComponent) )
class CRYPTRAIDER_API UGrabber : public USceneComponent
{
	GENERATED_BODY()

public:	
	// Sets default values for this component's properties
	UGrabber();

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

public:	
	// Called every frame
	virtual void TickComponent(float DeltaTime, ELevelTick TickType, FActorComponentTickFunction* ThisTickFunction) override;

	UFUNCTION(BlueprintCallable)
	void Grab();

	UFUNCTION(BlueprintCallable)
	void Release();

private: 
	UPROPERTY(EditAnywhere)
	float MaxGrabDistance = 400;

	UPROPERTY(EditAnywhere)
	float GrabRadius = 100;

	UPROPERTY(EditAnywhere)
	float HoldDistance = 200;

	UPhysicsHandleComponent* GetPhysicsHandle() const;

	bool GetGrabbableInReach(FHitResult& OutHitResult) const;
};

Grabber.cpp:

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

#include "Grabber.h"

#include "Engine/World.h"

#include "DrawDebugHelpers.h"

// Sets default values for this component's properties

UGrabber::UGrabber()

{

    // Set this component to be initialized when the game starts, and to be ticked every frame.  You can turn these features

    // off to improve performance if you don't need them.

    PrimaryComponentTick.bCanEverTick = true;

    // ...

}

// Called when the game starts

void UGrabber::BeginPlay()

{

    Super::BeginPlay();

   

}

// Called every frame

void UGrabber::TickComponent(float DeltaTime, ELevelTick TickType, FActorComponentTickFunction* ThisTickFunction)

{

    Super::TickComponent(DeltaTime, TickType, ThisTickFunction);

    if (PhysicsHandle && PhysicsHandle->GetGrabbedComponent())

    {

        FVector TargetLocation = GetComponentLocation() + GetForwardVector() * HoldDistance;

        PhysicsHandle->SetTargetLocationAndRotation(TargetLocation, GetComponentRotation());

    }

}

void UGrabber::Grab()

{

    UPhysicsHandleComponent* PhysicsHandle = GetPhysicsHandle();

    if (PhysicsHandle == nullptr)

    {

        return;

    }

    FHitResult HitResult;

    bool HasHit = GetGrabbableInReach(HitResult);

    if (HasHit)

    {

        UPrimitiveComponent* HitComponent = HitResult.GetComponent();

        HitComponent->WakeAllRigidBodies();

        HitResult.GetActor()->Tags.Add("Grabbed");

        PhysicsHandle->GrabComponentAtLocationWithRotation(

            HitComponent,

            NAME_None,

            HitResult.ImpactPoint,

            GetComponentRotation()

        );

    }

}

void UGrabber::Release()

{

    UPhysicsHandleComponent* PhysicsHandle = GetPhysicsHandle();

    if (PhysicsHandle && PhysicsHandle->GetGrabbedComponent())

    {

        AActor* GrabbedActor = PhysicsHandle->GetGrabbedComponent()->GetOwner();

        GrabbedActor->Tags.Remove("Grabbed");

        PhysicsHandle->ReleaseComponent();

    }

}

UPhysicsHandleComponent* UGrabber::GetPhysicsHandle() const

{

    UPhysicsHandleComponent* Result = GetOwner()->FindComponentByClass<UPhysicsHandleComponent>();

    if (Result == nullptr)

    {

        UE_LOG(LogTemp, Error, TEXT("Grabber Requires A UPhysicsHandleComponent"));

    }

    return Result;

}

bool UGrabber::GetGrabbableInReach(FHitResult& OutHitResult) const

{

    FVector Start = GetComponentLocation();

    FVector End = Start + GetForwardVector() * MaxGrabDistance;

    DrawDebugLine(GetWorld(), Start, End, FColor::Purple);

    DrawDebugSphere(GetWorld(), End, 10, 10, FColor::Blue, false, 5);

    FCollisionShape Sphere = FCollisionShape::MakeSphere(GrabRadius);

    return GetWorld()->SweepSingleByChannel(

        OutHitResult,

        Start, End,

        FQuat::Identity,

        ECC_GameTraceChannel2,

        Sphere);

}
#2

That would just give you the definition of the type UPhysicsHandleComponent, you never defined a member variable of that type in the header.

UPhysicsHandleComponent* PhysicsHandle;
#3

where would i need to place this in the code?

#4
#5

do i replace that line?

#6

Replace what line? You don’t have that line, which is the issue.

#7

i just tried compiling whilest adding this

it gave me the following errors:[1/5] Compile [x64] Grabber.cpp
C:\Users\Ezra\Documents\Unreal Projects\CryptRaider\Source\CryptRaider\Grabber.cpp(41): error C4458: declaration of ‘PhysicsHandle’ hides class member
C:\Users\Ezra\Documents\Unreal Projects\CryptRaider\Source\CryptRaider\Grabber.h(44): note: see declaration of ‘UGrabber::PhysicsHandle’
C:\Users\Ezra\Documents\Unreal Projects\CryptRaider\Source\CryptRaider\Grabber.cpp(71): error C4458: declaration of ‘PhysicsHandle’ hides class member
C:\Users\Ezra\Documents\Unreal Projects\CryptRaider\Source\CryptRaider\Grabber.h(44): note: see declaration of ‘UGrabber::PhysicsHandle’

#8

Sorry, I’ve lead you astray. Not sure where my mind was at yesterday. You were missing this line

With that said I think it would be better to instead just get the physics handle and store it as a member in BeginPlay. So you would have

// Called when the game starts
void UGrabber::BeginPlay()
{
    Super::BeginPlay();

    PhysicsHandle = GetOwner()->FindComponentByClass<UPhysicsHandleComponent>();
    // this will cause the editor to halt (crash) if PhysicsHandle is nullptr.
    check(PhysicsHandle); 
}

Then just use PhysicsHandle normally.

#9

it took a while to figure out, but i got passed the issue.

#10

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