Chapter 1, The Basics of AI in Games, aims to demystify some of the most basic concepts of AI as it is a very vast and intimidating topic.

Chapter 2, Finite State Machines and You, covers one of the most widely used concepts in AI—the finite state machine.

Chapter 3, Implementing Sensors, covers some of the most important ways for a game AI agent to perceive the world around it. The realism of an AI agent is directly linked to how it responds to its environment.

Chapter 4, Finding Your Way, covers the most widely used pattern in pathfinding for game AI agents. The agents in games need to traverse the areas of the game levels and maneuver around obstacles along the way.

Chapter 5, Flocks and Crowds, covers flocking and crowd simulation algorithms, allowing you to handle the unison movements of the agents in your game rather than having to figure out the logic for each agent.

Chapter 6, Behavior Trees, covers the process of implementing a custom behavior tree as it is one of the most common ways to implement complex and compound AI behaviors in games.

Chapter 7, Using Fuzzy Logic to Make Your AI Seem Alive, shows you how to let the game AI agents make decisions based on various factors in a non-binary way. Fuzzy logic mimics the way humans make decisions.

Chapter 8, How It All Comes Together, covers an example of how various systems come together in a single-objective game template that can be easily expanded upon.

To use the sample content provided with this book, you'll need a copy of Unity 5, which you can download for free from https://unity3d.com/get-unity. The system requirements for Unity can be found at https://unity3d.com/get-unity.

MonoDevelop, the IDE that comes bundled with Unity 5, is suggested but not required for this book as any text editor will do just fine. However, MonoDevelop comes with everything you need to write and debug code out of the box, including autocompletion, without the need for plugins or extensions.

This book is intended for Unity developers with a basic understanding of C# and the Unity editor. Whether you're looking to build your first game or trying to expand your knowledge as a game programmer, you will find plenty of exciting information and examples of game AI in terms of concepts and implementation. This book does not require any prior technical knowledge of how game AI works.

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: "We'll name it TankFsm."

A block of code is set as follows:

using UnityEngine;
using System.Collections;

public class TankPatrolState : StateMachineBehaviour {

   // OnStateEnter is called when a transition starts and the state machine starts to evaluate this state
   //override public void OnStateEnter(Animator animator, AnimatorStateInfo stateInfo, int layerIndex) {
   //
   //}

   // OnStateUpdate is called on each Update frame between OnStateEnter and OnStateExit callbacks
   //override public void OnStateUpdate(Animator animator, AnimatorStateInfo stateInfo, int layerIndex) {
   //
   //}

   // OnStateExit is called when a transition ends and the state machine finishes evaluating this state
   //override public void OnStateExit(Animator animator, AnimatorStateInfo stateInfo, int layerIndex) {
   //
   //}

   // OnStateMove is called right after Animator.OnAnimatorMove(). Code that processes and affects root motion should be implemented here
   //override public void OnStateMove(Animator animator, AnimatorStateInfo stateInfo, int layerIndex) {
   //
   //}

   // OnStateIK is called right after Animator.OnAnimatorIK(). Code that sets up animation IK (inverse kinematics) should be implemented here.
   //override public void OnStateIK(Animator animator, AnimatorStateInfo stateInfo, int layerIndex) {
   //
   //}
}

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: "When the panels are closed, you can still create new layers by clicking on the Layers dropdown and selecting Create New Layer."

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