Artificial Intelligence (AI) is an essential part of any game. It makes the virtual world we create more immersive and fun to play in. Game AI is different from the general scientific AI that we know; it is more targeted to solve key problems in game design, including navigation, which is how a nonplayer character (NPC) should move from one point to another and avoid obstacles; decision making, which is how to perform certain actions based on different situations; and environment sensing, which is the ability to understand what exists in the environment and what its status is. These techniques make it possible to create a dynamic and realistic gameplay so that the players will be more engaged in the world that is created for them.
Game AI is complicated and brings a lot of challenges if you want to develop on your own. Unreal Engine 4 is a powerful game engine that provides rich functionalities to create cross-platform 3D and 2D games. It is well known for its advanced graphics and highly customizable components. Now, it is free to use and open source, which makes it one of the most popular game engines out there. Unreal Engine 4 comes with a complete suite of tools for game AI, including NavMesh, Behavior Trees, and Environment Query System. With these tools in hand, it is much easier to bring AI to your games. For game designers, you can even use a visual scripting tool called Blueprints to build your game logic, including AI, by just connecting nodes and without even writing a single line of code.
This book is our effort to introduce these wonderful tools in Unreal Engine 4 to build game AI to game creators who are interested in making their virtual world more interesting. It will cover all the components we have mentioned and show you how to use each tool to build different character behaviors and combine them to create more complex scenes.
We can't wait to see what you will create!
Chapter 1, Introduction to Game AI?, introduces the basic idea of AI and how it directly affects and enhances the gaming experience. You will learn the differences between the traditional and game-specific goals of AI.
Chapter 2, Creating Basic AI, helps you create your first AI step by step and talks about the techniques we will demonstrate along the way. We will dive right into Unreal Engine 4, using the bare components needed to create a single state with random movement for your AI.
Chapter 3, Adding Randomness and Probability, teaches you how to create random and probability techniques that can be used to add randomness, chance, and character to AI, which will make the game unpredictable and more interesting. We will cover how these are used within Unreal Engine 4.
Chapter 4, Introducing Movement, explains how to introduce movement to our AI characters within Unreal Engine 4. Path Finding will be used to allow our character to intelligently navigate within a level.
Chapter 5, Giving AI Choices, explains how to introduce autonomous behavior to our characters using Behavior Trees. Behavior Trees are a methodology that allows you to construct your AI logic visually in a tree structure and can be reused in different characters.
Chapter 6, How Does Our AI Sense?, explains how to use the different components available within Unreal Engine 4 to enable our AI to sense other AI and the pawns we will place within the world.
Chapter 7, More Advanced Movement, focuses on flocking and more advanced path-following behaviors. Flocking allows us to create group behaviors for several AI characters.
Chapter 8, Creating Patrol, Chase, and Attack AI, combines some of the components we used in the previous chapters, including AI Sense and Movement, to have our AI character navigate. Then, we will apply randomness to the time that the AI character will spend chasing after the characters it detects.
Chapter 9, What Have We Learned?, briefly glances over the previous chapters. We will also talk about additional examples of what we can achieve with these combined lessons.
All you need is Unreal Engine 4.7.0, and you can download it from https://www.unrealengine.com.
This book is for programmers and artists who want to expand their knowledge of game AI in relation to Unreal Engine 4. It is recommended that you have some experience of exploring Unreal Engine 4 prior to this book because we will jump straight into game AI.
In this book, you will find a number of text styles that distinguish between different kinds of information. Here are some examples of these styles and an explanation of their meaning.
Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: "Now, place a comment around this and name it Chase Hero."
New terms and important words are shown in bold. Words that you see on the screen, for example, in menus or dialog boxes, appear in the text like this: "If you're in Unreal Engine and you navigate to the Modes panel under Volumes, you'll see NavMeshBoundsVolume."
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