Floating Actor

December 02, 2017

UE4 Version: 4.18.3

Github Link: https://github.com/Harrison1/unrealcpp/tree/master/FloatingActor

For this tutorial we are using the standard first person C++ template with starter content. If you don't know how to add a new actor class to your project, please visit the Add C++ Actor Class post.

In this tutorial the main logic came from one of Epic's Unreal Engine 4 C++ tutorials, you can find the link here. Also, here is great forum discussing the code in greater depth. Tim is rockstar for providing a stellar answer.

Create a new C++ actor class and call it Floating Actor. In the header file will create four float variables. We will create RunningTime, XValue, YValue, and ZValue variables. Below is the final header code.

FloatingActor.h

#pragma once

#include "CoreMinimal.h"
#include "GameFramework/Actor.h"
#include "FloatingActor.generated.h"

UCLASS()
class UNREALCPP_API AFloatingActor : public AActor
{
	GENERATED_BODY()
	
public:	
	// Sets default values for this actor's properties
	AFloatingActor();

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

public:	
	// Called every frame
	virtual void Tick(float DeltaTime) override;

	// declare our float variables 
	float RunningTime;
	
	UPROPERTY(EditAnywhere, Category = Movement)
	float XValue;

	UPROPERTY(EditAnywhere, Category = Movement)
	float YValue;

	UPROPERTY(EditAnywhere, Category = Movement)
	float ZValue;
	
	
};

Next, we will be putting all of our logic in our Tick function. To start off, let's declare a variable every frame that equals the actor's current location by using GetActorLocation. This will allow us to change the X,Y, and Z values of actor and mov it on scene. For smooth motion we will be using the FMath:Sin to set our DeltaHeight variable.

DeltaHeight

float DeltaHeight = (FMath::Sin(RunningTime + DeltaTime) - FMath::Sin(RunningTime));

Next, we are going get our actor's location X,Y, and Z coordinates and add DeltaTIme * Value to them. In the header file we made the variables editable anywhere so in the editor we can easily adjust the amount and direction the actor moves. Next, set RunningTime to DeltaHeight. Finally set the actor's location to the NewLocation. Below is the final .cpp final.

FloatingActor.cpp

#include "FloatingActor.h"


// Sets default values
AFloatingActor::AFloatingActor()
{
 	// 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;

}

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

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

	// on every frame change location for a smooth floating actor
	FVector NewLocation = GetActorLocation();
	float DeltaHeight = (FMath::Sin(RunningTime + DeltaTime) - FMath::Sin(RunningTime));
	NewLocation.X += DeltaHeight *  XValue;
	NewLocation.Y += DeltaHeight *  YValue;
	NewLocation.Z += DeltaHeight *  ZValue;

	RunningTime += DeltaTime;
	SetActorLocation(NewLocation);

}

Author

Harrison McGuire

Harrison McGuire