Unreal Engine 4 Scripting with C++ Cookbook

Unreal Engine 4 Scripting with C++ Cookbook

By : William Sherif, Stephen Whittle

Buy this Book

Unreal Engine 4 Scripting with C++ Cookbook

By: William Sherif, Stephen Whittle

Buy this Book

Overview of this book

Unreal Engine 4 (UE4) is a complete suite of game development tools made by game developers, for game developers. With more than 100 practical recipes, this book is a guide showcasing techniques to use the power of C++ scripting while developing games with UE4. It will start with adding and editing C++ classes from within the Unreal Editor. It will delve into one of Unreal's primary strengths, the ability for designers to customize programmer-developed actors and components. It will help you understand the benefits of when and how to use C++ as the scripting tool. With a blend of task-oriented recipes, this book will provide actionable information about scripting games with UE4, and manipulating the game and the development environment using C++. Towards the end of the book, you will be empowered to become a top-notch developer with Unreal Engine 4 using C++ as the scripting language.

Unreal Engine 4 Scripting with C++ Cookbook

Credits

About the Authors

About the Reviewer

www.PacktPub.com

Preface

Free Chapter

UE4 Development Tools

Introduction

Installing Visual Studio

Creating and building your first C++ project in Visual Studio

Changing the code font and color in Visual Studio

Extension – changing the color theme in Visual Studio

Formatting your code (Autocomplete settings) in Visual Studio

Shortcut keys in Visual Studio

Extended mouse usage in Visual Studio

UE4 – installation

UE4 – first project

UE4 – creating your first level

UE4 – logging with UE_LOG

UE4 – making an FString from FStrings and other variables

Project management on GitHub – getting your Source Control

Project management on GitHub – using the Issue Tracker

Project management on VisualStudio.com – managing the tasks in your project

Project management on VisualStudio.com – constructing user stories and tasks

Creating Classes

Introduction

Making a UCLASS – deriving from UObject

Creating a user-editable UPROPERTY

Accessing a UPROPERTY from Blueprints

Specifying a UCLASS as the type of a UPROPERTY

Creating a Blueprint from your custom UCLASS

Instantiating UObject-derived classes (ConstructObject < > and NewObject < >)

Destroying UObject-derived classes

Creating a USTRUCT

Creating a UENUM( )

Creating a UFUNCTION

Memory Management and Smart Pointers

Introduction

Unmanaged memory – using malloc( )/free( )

Unmanaged memory – using new/delete

Managed memory – using NewObject< > and ConstructObject< >

Managed memory – deallocating memory

Managed memory – smart pointers (TSharedPtr, TWeakPtr, TAutoPtr) to track an object

Using TScopedPointer to track an object

Unreal's garbage collection system and UPROPERTY( )

Forcing garbage collection

Breakpoints and stepping through code

Finding bugs and using call stacks

Using the Profiler to identify hot spots

Actors and Components

Introduction

Creating a custom Actor in C++

Instantiating an Actor using SpawnActor

Destroying an Actor using Destroy and a Timer

Destroying an Actor after a delay using SetLifeSpan

Implementing the Actor functionality by composition

Loading assets into components using FObjectFinder

Implementing the Actor functionality by inheritance

Attaching components to create a hierarchy

Creating a custom Actor Component

Creating a custom Scene Component

Creating a custom Primitive Component

Creating an InventoryComponent for an RPG

Creating an OrbitingMovement Component

Creating a building that spawns units

Handling Events and Delegates

Handling events implemented via virtual functions

Creating a delegate that is bound to a UFUNCTION

Unregistering a delegate

Creating a delegate that takes input parameters

Passing payload data with a delegate binding

Creating a multicast delegate

Creating a custom Event

Creating a Time of Day handler

Creating a respawning pickup for an First Person Shooter

Input and Collision

Introduction

Axis Mappings – keyboard, mouse and gamepad directional input for an FPS character

Axis Mappings – normalized input

Action Mappings – one button responses for an FPS character

Adding Axis and Action Mappings from C++

Mouse UI input handling

UMG keyboard UI shortcut keys

Collision – letting objects pass through one another using Ignore

Collision – picking up objects using Overlap

Collision – preventing interpenetration using Block

Communication between Classes and Interfaces

Introduction

Creating a UInterface

Implementing a UInterface on an object

Checking if a class implements a UInterface

Casting to a UInterface implemented in native code

Calling native UInterface functions from C++

Inheriting UInterface from one another

Overriding UInterface functions in C++

Exposing UInterface methods to Blueprint from a native base class

Implementing UInterface functions in Blueprint

Creating C++ UInterface function implementations that can be overridden in Blueprint

Calling Blueprint-defined interface functions from C++

Implementing a simple interaction system with UInterfaces

Integrating C++ and the Unreal Editor

Introduction

Using a class or struct as a blueprint variable

Creating classes or structs that can be subclassed in Blueprint

Creating functions that can be called in Blueprint

Creating events that can be implemented in Blueprint

Exposing multi-cast delegates to Blueprint

Creating C++ enums that can be used in Blueprint

Editing class properties in different places in the editor

Making properties accessible in the Blueprint editor graph

Responding to property – changed events from the editor

Implementing a native code Construction Script

Creating a new editor module

Creating new toolbar buttons

Creating new menu entries

Creating a new editor window

Creating a new Asset type

Creating custom context menu entries for Assets

Creating new console commands

Creating a new graph pin visualizer for Blueprint

Inspecting types with custom Details panels

User Interfaces – UI and UMG

Introduction

Drawing using Canvas

Adding Slate Widgets to the screen

Creating screen size-aware scaling for the UI

Displaying and hiding a sheet of UMG elements in-game

Attaching function calls to Slate events

Use Data Binding with Unreal Motion Graphics

Controlling widget appearance with Styles

Create a custom SWidget/UWidget

AI for Controlling NPCs

Introduction

Laying down a Navigation Mesh

Following behavior

Connecting a Behavior Tree to a Character

Constructing Task nodes

Using Decorators for conditions

Using periodic services

Using Composite nodes – Selectors, Sequences, and Simple Parallel

AI for a Melee Attacker

Custom Materials and Shaders

Introduction

Modifying color using a basic Material

Modifying position using a Material

Shader code via Custom node

The Material function

Shader parameters and Material instances

Glimmer

Leaves and Wind

Reflectance dependent on the viewing angle

Randomness – Perlin noise

Shading a Landscape

Working with UE4 APIs

Introduction

Core/Logging API – Defining a custom log category

Core/Logging API – FMessageLog to write messages to the Message Log

Core/Math API – Rotation using FRotator

Core/Math API – Rotation using FQuat

Core/Math API – Rotation using FRotationMatrix to have one object face another

Landscape API – Landscape generation with Perlin noise

Foliage API – Adding trees procedurally to your level

Landscape and Foliage API – Map generation using Landscape and Foliage APIs

GameplayAbilities API – Triggering an actor's gameplay abilities with game controls

GameplayAbilities API – Implementing stats with UAttributeSet

GameplayAbilities API – Implementing buffs with GameplayEffect

GameplayTags API – Attaching GameplayTags to an Actor

GameplayTasks API – Making things happen with GameplayTasks

HTTP API – Web request

HTTP API – Progress bars

Index

Customer Reviews

5 star

4 star

3 star

2 star

1 star

UE4 – making an FString from FStrings and other variables

When coding in UE4, you often want to construct a string from variables. This is pretty easy using the FString::Printf or FString::Format functions.

Getting ready

For this, you should have an existing project into which you can enter some UE4 C++ code. Putting variables into a string is possible via printing. It may be counterintuitive to print into a string, but you can't just concatenate variables together, and hope that they will automatically convert to string, as in some languages such as JavaScript.

How to do it…

Using FString::Printf():
1. Consider the variables you'd like printed into your string.
2. Open and take a look at a reference page of the printf format specifiers, such as http://en.cppreference.com/w/cpp/io/c/fprintf.
3. Try code such as the following:
```
FString name = "Tim";
int32 mana = 450;
FString string = FString::Printf( TEXT( "Name = %s Mana = %d" ), *name, mana );
```
Notice how the preceding code block uses the format specifiers precisely as the traditional printf function does. In the preceding example, we used %s to place a string in the formatted string, and %d to place an integer in the formatted string. Different format specifiers exist for different types of variables, and you should look them up on a site such as cppreference.com.

Using FString::Format(). Write code in the following form:

FString name = "Tim";
int32 mana = 450;
TArray< FStringFormatArg > args;
args.Add( FStringFormatArg( name ) );
args.Add( FStringFormatArg( mana ) );
FString string = FString::Format( TEXT( "Name = {0} Mana = {1}" ), args );
UE_LOG( LogTemp, Warning, TEXT( "Your string: %s" ), *string );

With FString::Format(), instead of using correct format specifiers, we use simple integers and a TArray of FStringFormatArg instead. The FstringFormatArg helps FString::Format() deduce the type of variable to put in the string.

Unreal Engine 4 Scripting with C++ Cookbook

By : William Sherif, Stephen Whittle

Unreal Engine 4 Scripting with C++ Cookbook

By: William Sherif, Stephen Whittle

Overview of this book

Related Content you might be interested in

Current Title:

Unreal Engine 4 Scripting with C++ Cookbook

UE4 – making an FString from FStrings and other variables

Getting ready

How to do it…