Unreal engine cpp files

Содержание

Programming Quick Start
Create your first code project and add a new C++ class.
1. Required Setup
2. Create a New C++ Class
3. Edit Your C++ Class
4. Compile and Test Your C++ Code
5. End Result
6. On Your Own!
Sample Code

Programming Quick Start

Create your first code project and add a new C++ class.

In order to understand and use the content on this page, make sure you are familiar with the following topics:

Choose your operating system:

In this Quick Start Guide, you will learn how to set up a C++ project in the Unreal Engine and program your first C++ gameplay class in Visual Studio. By the time you’ve completed this tutorial, you will know how to do the following:

Create a new C++ Project
Create a new Actor class in C++
Edit that C++ class in your development environment, adding visual representation and functionality
Compile your project
Test your new Actor in the Unreal Editor

This guide assumes that you have already set up Visual Studio as your programming environment. If not, please refer to Setting Up Visual Studio for the Unreal Engine for instructions on how to install it and get it set up for programming with the Unreal Engine. We also assume that you have some familiarity with using the Unreal Editor before starting this guide, but for your convenience we will walk through all the steps necessary to create and manage C++ classes from the editor. The end product of this guide will be a cube that floats softly in mid-air and continually rotates, giving you a simple object to test as you learn to use the development environment for programming.

This guide assumes that you have already set up XCode as your programming environment. We also assume that you have some familiarity with using the Unreal Editor before starting this guide, but for your convenience we will walk through all the steps necessary to create and manage C++ classes from the editor. The end product of this guide will be a cube that floats softly in mid-air and continually rotates, giving you a simple object to test as you learn to use the development environment for programming.

1. Required Setup

Launch the Unreal Editor. When the Project Browser comes up, click Games Project category and select a Blank template. Make sure that you have C++ and Starter Content enabled, choose your preferred Save Location and Name for this project, and then click Create Project. In our instance, we’re naming our project QuickStart.

This will automatically create a simple, blank project with only essential C++ code in the solution, and it will automatically open inside both the Unreal Editor and Visual Studio. For more information on managing and creating Projects, please refer to the Project Browser page.

This will automatically create a simple, blank project with only essential C++ code in the solution, and it will automatically open inside both the Unreal Editor and XCode. For more information on managing and creating Projects, please refer to the Project Browser page.

Any Blueprint project can be converted to a C++ project. If you have a Blueprint project that you want to add C++ to, create a new C++ class per the next section, and the editor will set up your code environment for you. Also note that using a C++ project does not prevent you from using Blueprint. C++ projects simply set up the base classes for your project in C++ instead of Blueprint.

2. Create a New C++ Class

In the Unreal Editor, click the File drop-down menu, then select the New C++ Class. command.

3. Edit Your C++ Class

Now that we have created our C++ Class, we’re going to switch over to Visual Studio and edit our code.

Visual Studio

Solution Explorer

Games > QuickStart > Source > QuickStart

Double-click FloatingActor.h to open it and bring it into focus in the text editor.

UPROPERTY(VisibleAnywhere) UStaticMeshComponent* VisualMesh;

Here we’re declaring a StaticMeshComponent, which will act as our visual representation for our object. Note that it uses a UProperty macro, which makes it visible inside the Unreal Editor. For more information on UProperty and its specifiers, see the page on

VisualMesh = CreateDefaultSubobject(TEXT("Mesh")); VisualMesh->SetupAttachment(RootComponent); static ConstructorHelpers::FObjectFinder CubeVisualAsset(TEXT("/Game/StarterContent/Shapes/Shape_Cube.Shape_Cube")); if (CubeVisualAsset.Succeeded()) < VisualMesh->SetStaticMesh(CubeVisualAsset.Object); VisualMesh->SetRelativeLocation(FVector(0.0f, 0.0f, 0.0f)); >

FVector NewLocation = GetActorLocation(); FRotator NewRotation = GetActorRotation(); float RunningTime = GetGameTimeSinceCreation(); float DeltaHeight = (FMath::Sin(RunningTime + DeltaTime) - FMath::Sin(RunningTime)); NewLocation.Z += DeltaHeight * 20.0f; //Scale our height by a factor of 20 float DeltaRotation = DeltaTime * 20.0f; //Rotate by 20 degrees per second NewRotation.Yaw += DeltaRotation; SetActorLocationAndRotation(NewLocation, NewRotation);

The Tick function is where we add code that we want to execute in real-time. In this case, it will make our cube simultaneously rotate while also floating up and down. For more information about Ticking actors, see

Now that we have created our C++ Class, we’re going to switch over to XCode and edit our code.

XCode

Project Navigator

Games > QuickStart > Source > QuickStart

UPROPERTY(VisibleAnywhere) UStaticMeshComponent* VisualMesh;

VisualMesh = CreateDefaultSubobject(TEXT("Mesh")); VisualMesh->SetupAttachment(RootComponent); static ConstructorHelpers::FObjectFinder CubeVisualAsset(TEXT("/Game/StarterContent/Shapes/Shape_Cube.Shape_Cube")); if (CubeVisualAsset.Succeeded()) < VisualMesh->SetStaticMesh(CubeVisualAsset.Object); VisualMesh->SetRelativeLocation(FVector(0.0f, 0.0f, 0.0f)); >

FVector NewLocation = GetActorLocation(); FRotator NewRotation = GetActorRotation(); float RunningTime = GetGameTimeSinceCreation(); float DeltaHeight = (FMath::Sin(RunningTime + DeltaTime) - FMath::Sin(RunningTime)); NewLocation.Z += DeltaHeight * 20.0f; //Scale our height by a factor of 20 float DeltaRotation = DeltaTime * 20.0f; //Rotate by 20 degrees per second NewRotation.Yaw += DeltaRotation; SetActorLocationAndRotation(NewLocation, NewRotation);

4. Compile and Test Your C++ Code

Save your work in both FloatingActor.h and FloatingActor.cpp . Then, in the Solution Explorer, right-click the project, click the Build command in the context menu, and wait for the project to finish compiling.

You should see a message that says «Succeeded» in the Output log at the bottom of the window.

Alternatively, you can go back to the Unreal Editor and click the Compile button in the toolbar at the top of the screen.

You should always save your work before attempting to compile, otherwise the changes you make in your code will not take effect.

In the Unreal Editor, go back to the Content Browser, unfold C++ Classes, and then locate FloatingActor. It will be located in the folder that has the same name as your project, in our case, QuickStart.

Click and drag FloatingActor into the Perspective Viewport to create an instance of FloatingActor. It will be selected in the World Outliner as «FloatingActor1» and its properties will be visible in the Details Panel.

For more information about navigating the Viewport and placing Actors in the World, refer to the Level Designer Quick Start .
In the Details Panel for FloatingActor1, set your Actor’s Location to (-180, 0, 180). This will place it directly over the table in the default scene.

Alternatively, you can use the Move gizmo to move it there manually.

Press the Play In Editor button at the top of the screen.

Save your work in both FloatingActor.h and FloatingActor.cpp . Then, click the Product drop-down menu at the top of the screen, select the Build command, and wait for the project to finish building.

You should see a message that says «Succeeded» in the Output log at the bottom of the window. Alternatively, you can go back to the Unreal Editor and click the Compile button in the toolbar at the top of the screen.

You should always save your work before attempting to compile, otherwise the changes you make in your code will not take effect.

Alternatively, you can use the Move gizmo to move it there manually.

Press the Play In Editor button at the top of the screen.

5. End Result

You should now see your cube gently floating up and down over the table while it slowly rotates.

Congratulations! You’ve created your first Actor class entirely with C++! While this represents a very simple object and only scratches the surface of what you can do with C++ source code, you have at this point touched on all the essentials of creating, editing, and compiling C++ code for your game. You are now ready for more complex gameplay programming challenges, and we suggest a few below.

6. On Your Own!

Now that you know how to build a simple C++ Actor, try making it more configurable. For instance, you can add variables to control its behavior:

In FloatingActor.h:

. public: UPROPERTY(EditAnywhere, BlueprintReadWrite, Category="FloatingActor") float FloatSpeed = 20.0f; UPROPERTY(EditAnywhere, BlueprintReadWrite, Category="FloatingActor") float RotationSpeed = 20.0f; .

In FloatingActor.cpp:

. NewLocation.Z += DeltaHeight * FloatSpeed; //Scale our height by FloatSpeed float DeltaRotation = DeltaTime * RotationSpeed; //Rotate by a number of degrees equal to RotationSpeed each second .

By adding these variables in the header and replacing the float values we were using to scale DeltaHeight and DeltaRotation in the .cpp, we can now edit the float and rotation speed in the Details Panel when we select our Actor.

You can experiment by adding other kinds of behavior to the Tick function using Location, Rotation, and Scale.

You can also try attaching other kinds of components in C++ to create a more complex object. Refer to the Creating and Attaching Components guide for examples of different types of components you have available, and try adding a Particle System Component to add a bit of flare to your floating object.

Finally, if you right-click your own Actor class in the Content Browser, you will find the option to extend it, either in C++ or in Blueprint, enabling you to create new variations of it.

You can have a whole library of FloatingActors, each substituting different Meshes or parameters as you so choose.

Sample Code

FloatingActor.h

// Copyright 1998-2019 Epic Games, Inc. All Rights Reserved. #pragma once #include "CoreMinimal.h" #include "GameFramework/Actor.h" #include "FloatingActor.generated.h" UCLASS() class QUICKSTART_API AFloatingActor : public AActor < GENERATED_BODY() public: // Sets default values for this actor's properties AFloatingActor(); UPROPERTY(VisibleAnywhere) UStaticMeshComponent* VisualMesh; protected: // Called when the game starts or when spawned virtual void BeginPlay() override; public: // Called every frame virtual void Tick(float DeltaTime) override; >;

FloatingActor.cpp

// Copyright 1998-2019 Epic Games, Inc. All Rights Reserved. #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; VisualMesh = CreateDefaultSubobject(TEXT("Mesh")); VisualMesh->SetupAttachment(RootComponent); static ConstructorHelpers::FObjectFinder CubeVisualAsset(TEXT("/Game/StarterContent/Shapes/Shape_Cube.Shape_Cube")); if (CubeVisualAsset.Succeeded()) < VisualMesh->SetStaticMesh(CubeVisualAsset.Object); VisualMesh->SetRelativeLocation(FVector(0.0f, 0.0f, 0.0f)); > > // Called when the game starts or when spawned void AFloatingActor::BeginPlay() < Super::BeginPlay(); >// Called every frame void AFloatingActor::Tick(float DeltaTime) < Super::Tick(DeltaTime); FVector NewLocation = GetActorLocation(); FRotator NewRotation = GetActorRotation(); float RunningTime = GetGameTimeSinceCreation(); float DeltaHeight = (FMath::Sin(RunningTime + DeltaTime) - FMath::Sin(RunningTime)); NewLocation.Z += DeltaHeight * 20.0f; //Scale our height by a factor of 20 float DeltaRotation = DeltaTime * 20.0f; //Rotate by 20 degrees per second NewRotation.Yaw += DeltaRotation; SetActorLocationAndRotation(NewLocation, NewRotation); >

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