Example AActor-derived class for Unreal Engine 4

UE4WallSconce.cpp

/* An example UE4 class derived from AActor. It plays a
 * sound when an actor enters the bounding box, and lets
 * the player turn a PointLight on and off using the "Use"
 * key. It originally existed as a blueprint. */
 
/* WallSconceCpp.h */

#pragma once

#include "GameFramework/Actor.h"
#include "WallSconceCpp.generated.h"

UCLASS()
class WTF_API AWallSconceCpp : public AActor
{
	GENERATED_BODY()
	
public:	
	// Sets default values for this actor's properties
	AWallSconceCpp(const FObjectInitializer &ObjectInitializer);

	// Called when the game starts or when spawned
	virtual void BeginPlay() override;
	
	// Called every frame
	virtual void Tick( float DeltaSeconds ) override;

	// Called when another actor overlaps with this one
	UFUNCTION()
	void OnBeginOverlap(AActor *otherActor);

	// Called when another actor stops overlapping with this one
	UFUNCTION()
	void OnEndOverlap(AActor *otherActor);

	UFUNCTION()
	void Use();

	UPROPERTY(VisibleDefaultsOnly, BlueprintReadOnly)
	class UStaticMeshComponent *mesh;

	UPROPERTY(VisibleDefaultsOnly, BlueprintReadOnly)
	class UPointLightComponent *light;

	UPROPERTY(VisibleDefaultsOnly, BlueprintReadOnly)
	class UAudioComponent *audio;

	UPROPERTY(VisibleDefaultsOnly, BlueprintReadOnly)
	class UBoxComponent *useArea;
};

/* WallSconceCpp.cpp */
#include "wtf.h"
#include "WallSconceCpp.h"


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

	mesh = ObjectInitializer.CreateDefaultSubobject<UStaticMeshComponent>(this, TEXT("LampMesh"));
	light = ObjectInitializer.CreateDefaultSubobject<UPointLightComponent>(this, TEXT("PointLight"));
	audio = ObjectInitializer.CreateDefaultSubobject<UAudioComponent>(this, TEXT("Audio"));
	useArea = ObjectInitializer.CreateDefaultSubobject<UBoxComponent>(this, TEXT("Box"));
	
	/* Initialize the component hierarchy */
	SetRootComponent(useArea);
	mesh->AttachTo(useArea);
	light->AttachTo(useArea);
	audio->AttachTo(useArea);
	
	/* Make the box collider generate events, so we know the player has entered the area */
	useArea->bGenerateOverlapEvents = true;
	/* Make the box collider default a little larger */
	useArea->InitBoxExtent(FVector(100, 100, 100));
	/* Make the light float a little above the static mesh */
	light->SetRelativeLocation(FVector(0, 0, 50));
	/* Don't play the audio by default */
	audio->SetActive(false);
	/* Don't light up by default */
	light->SetVisibility(false);

  /* Bind events */
	OnActorBeginOverlap.AddDynamic(this, &AWallSconceCpp::OnBeginOverlap);
	OnActorEndOverlap.AddDynamic(this, &AWallSconceCpp::OnEndOverlap);
}

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

  /* I'm not totally sure whether this is proper or not, but it seems like
   * the PlayerController was invalid in the constructor above, so setup
   * the toggle light event here */
	InputComponent = GetWorld()->GetFirstPlayerController()->InputComponent;
	InputComponent->BindAction("Use", IE_Pressed, this, &AWallSconceCpp::Use);
}

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

void AWallSconceCpp::OnBeginOverlap(AActor *otherActor)
{
  /* Toggle audio and allow the player to toggle the light
   * when they enter the box collider */
	audio->SetActive(true);
	EnableInput(GetWorld()->GetFirstPlayerController());
}

void AWallSconceCpp::OnEndOverlap(AActor *otherActor)
{
  /* Toggle audio and don't allow the player to toggle the
   * light when they exit the box collider */
	audio->SetActive(false);
	DisableInput(GetWorld()->GetFirstPlayerController());
}

void AWallSconceCpp::Use()
{
  /* Toggle the light when the player presses "Use"*/
	light->ToggleVisibility();
}