Grabber.cpp

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

#include "Grabber.h"
#include "GameFramework/Actor.h"
#include "Engine/World.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();
	FindPhysicsHandlerComponent();

	///Look for attached Physics Handl(only appears at runtime)
	InputComponent = GetOwner()->FindComponentByClass<UInputComponent>();
	if (InputComponent)
	{
		UE_LOG(LogTemp, Warning, TEXT("Input Component found"));
		///Bind the input axis
		InputComponent->BindAction("Grab", IE_Pressed, this, &UGrabber::Grab);
		InputComponent->BindAction("Grab", IE_Released, this, &UGrabber::Release);
	}
	else
	{
		UE_LOG(LogTemp, Error, TEXT("%s missing input component"), *GetOwner()->GetName());
	}
}

void UGrabber::Grab() {
	UE_LOG(LogTemp, Warning, TEXT("Grab pressed"));
}

void UGrabber::Release() {
	UE_LOG(LogTemp, Warning, TEXT("Grab released"));
}

void UGrabber::FindPhysicsHandlerComponent()
{
	//Look for attached Physics Handl
	PhysicsHandle = GetOwner()->FindComponentByClass<UPhysicsComponent>();
	if (PhysicsHandle)
	{

	}
	else
	{
		UE_LOG(LogTemp, Error, TEXT("%s missing handle component"), *GetOwner()->GetName());
	}
}
// Called every frame
void UGrabber::TickComponent(float DeltaTime, ELevelTick TickType, FActorComponentTickFunction* ThisTickFunction)
{
	Super::TickComponent(DeltaTime, TickType, ThisTickFunction);

	//Get player view point this tick
	FVector PlayerViewPointLocation;
	FRotator PlayerViewPointRotation;

	GetWorld()->GetFirstPlayerController()->GetPlayerViewPoint(
		OUT PlayerViewPointLocation,
		OUT PlayerViewPointRotation
	);
	// TODO Log out to test
	//UE_LOG(LogTemp, Warning, TEXT("Player location: %s ,Player rotation: %s"), 
	//	*PlayerViewPointLocation.ToString(), 
	//	*PlayerViewPointRotation.ToString()
	//)
	
	FVector LineTraceEnd = PlayerViewPointLocation + PlayerViewPointRotation.Vector() * Reach;
	//Draw a red trace in the world to visual
	DrawDebugLine(
		GetWorld(),
		PlayerViewPointLocation,
		LineTraceEnd,
		FColor(255, 0, 0),
		false,
		0.f,
		0.f,
		10.f
	);

	///Setup query params
	FCollisionQueryParams TraceParameters(FName(TEXT("")), false, GetOwner());

	///Line-trace (AKA Ray-cast) out to reach distance
	FHitResult Hit;
	GetWorld()->LineTraceSingleByObjectType(
		OUT Hit,
		PlayerViewPointLocation,
		LineTraceEnd,
		FCollisionObjectQueryParams(ECollisionChannel::ECC_PhysicsBody),
		TraceParameters
	);

	//See what we hit
	AActor*ActorHit = Hit.GetActor();
	if (ActorHit)
	{
		UE_LOG(LogTemp, Warning, TEXT("Line trace hit: %s"), *(ActorHit->GetName()));
	}
}

Grabber.h

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

#pragma once

#include "CoreMinimal.h"
#include "DrawDebugHelpers.h"
#include "Components/ActorComponent.h"
#include "PhysicsEngine/PhysicsHandleComponent.h"
#include "Components/InputComponent.h"
#include "Grabber.generated.h"


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;

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

private:
	//how far ahead of the player can we reach in cm
	float Reach = 100.f;

	UPhysicsComponent* PhysicsHandle = nullptr;
	UInputComponent* InputComponent = nullptr;

	//Ray-cast and grab what is in reach
	void Grab();

	void Release();

	//find attached physics handle
	void FindPhysicsHandlerComponent();

};