My Refactored Code for Building Escape Grabber Class

grabber.cpp

// Copyright Aaron Gravelle

#include "Grabber.h"

#define OUT

// 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();

	SetupInputComponent();
	SetupPhysicsHandleComponent();
}

// Called every frame
void UGrabber::TickComponent(float DeltaTime, ELevelTick TickType, FActorComponentTickFunction* ThisTickFunction) {
	Super::TickComponent(DeltaTime, TickType, ThisTickFunction);
	
	// If the physics handle is attached
	if (PhysicsHandle->GrabbedComponent) {
		// move the object that we're holding
		PhysicsHandle->SetTargetLocation(GetEndOfReach());
	}
}

void UGrabber::SetupInputComponent() {
	InputComponent = GetOwner()->FindComponentByClass<UInputComponent>();
	if (InputComponent) {
		/// Bind the input action
		InputComponent->BindAction("Grab", IE_Pressed, this, &UGrabber::Grab);
		InputComponent->BindAction("Grab", IE_Released, this, &UGrabber::Release);
	}
	else {
		UE_LOG(LogTemp, Error, TEXT("%s is missing InputComponent"), *(GetOwner()->GetName()));
	}
}

void UGrabber::SetupPhysicsHandleComponent() {
	/// Look for attached Physics Handle
	PhysicsHandle = GetOwner()->FindComponentByClass<UPhysicsHandleComponent>();
	if (!PhysicsHandle) {
		UE_LOG(LogTemp, Error, TEXT("%s is missing PhysicsHandleComponent"), *(GetOwner()->GetName()));
	}
}

void UGrabber::Grab() {
	/// LINE TRACE and see if any actors with physics body collision channel set
	auto ComponentToGrab = GetFirstPhysicsBodyInReach().GetComponent();

	/// If we hit something then attach a physics handle
	if (ComponentToGrab) {
		//  attach physics handle
		PhysicsHandle->GrabComponentAtLocation(
			ComponentToGrab,
			NAME_None,
			ComponentToGrab->GetOwner()->GetActorLocation()
		);
	}
}

void UGrabber::Release() {
	PhysicsHandle->ReleaseComponent();
}

FHitResult UGrabber::GetFirstPhysicsBodyInReach() const {
	/// Setup query parameter
	FCollisionQueryParams TraceParameters(FName(TEXT("")), false, GetOwner());

	/// Ray-cast to reach distance
	FHitResult PhysicsBody;
	GetWorld()->LineTraceSingleByObjectType(
		OUT PhysicsBody,
		GetOwner()->GetActorLocation(),
		GetEndOfReach(),
		FCollisionObjectQueryParams(ECollisionChannel::ECC_PhysicsBody),
		TraceParameters
	);

	return PhysicsBody;
}

FVector UGrabber::GetEndOfReach() const
{
	PlayerPOV CurrentPOV = GetPlayerPOV();
	return CurrentPOV.Location + (Reach * CurrentPOV.Rotation.Vector());
}

PlayerPOV UGrabber::GetPlayerPOV() const
{
	PlayerPOV CurrentPOV;
	GetWorld()->GetFirstPlayerController()->GetPlayerViewPoint(OUT CurrentPOV.Location, OUT CurrentPOV.Rotation);
	return CurrentPOV;
}

grabber.h

#pragma once

#include "CoreMinimal.h"
#include "Components/ActorComponent.h"
#include "PhysicsEngine/PhysicsHandleComponent.h"
#include "DrawDebugHelpers.h"
#include "Engine/World.h"
#include "GameFramework/PlayerController.h"
#include "Grabber.generated.h"

struct PlayerPOV {
	FVector Location;
	FRotator Rotation;
};

UCLASS( ClassGroup=(Custom), meta=(BlueprintSpawnableComponent) )
class BUILDINGESCAPE_API UGrabber : public UActorComponent
{
	GENERATED_BODY()

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

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

	// Find (assumed) attached input component
	void SetupInputComponent();

	// Setup (assumed) attached physics component
	void SetupPhysicsHandleComponent();

	// Return hit for first physics body in reach 
	FHitResult GetFirstPhysicsBodyInReach() const;

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

private:

	// How far ahead the player can reach in cm
	UPROPERTY(EditAnywhere)
	float Reach = 100.f;

	UPhysicsHandleComponent* PhysicsHandle = nullptr;
	UInputComponent* InputComponent = nullptr;

	/// Ray-cast and grab what is in reach
	void Grab();
	void Release();
	PlayerPOV GetPlayerPOV() const;
	FVector GetEndOfReach() const;
};