Book Image

Unity Artificial Intelligence Programming - Fifth Edition

By : Dr. Davide Aversa
Book Image

Unity Artificial Intelligence Programming - Fifth Edition

By: Dr. Davide Aversa

Overview of this book

Developing artificial intelligence (AI) for game characters in Unity has never been easier. Unity provides game and app developers with a variety of tools to implement AI, from basic techniques to cutting-edge machine learning-powered agents. Leveraging these tools via Unity's API or built-in features allows limitless possibilities when it comes to creating game worlds and characters. The updated fifth edition of Unity Artificial Intelligence Programming starts by breaking down AI into simple concepts. Using a variety of examples, the book then takes those concepts and walks you through actual implementations designed to highlight key concepts and features related to game AI in Unity. As you progress, you’ll learn how to implement a finite state machine (FSM) to determine how your AI behaves, apply probability and randomness to make games less predictable, and implement a basic sensory system. Later, you’ll understand how to set up a game map with a navigation mesh, incorporate movement through techniques such as A* pathfinding, and provide characters with decision-making abilities using behavior trees. By the end of this Unity book, you’ll have the skills you need to bring together all the concepts and practical lessons you’ve learned to build an impressive vehicle battle game.
Table of Contents (17 chapters)
1
Part 1:Basic AI
6
Part 2:Movement and Navigation
11
Part 3:Advanced AI

Introduction to BTs

A BT is a hierarchical tree of nodes that controls the AI character's behavior flow. It can also be used to coordinate groups of characters (for example, to model the attack pattern of a small platoon), or even disembodied agents such as an AI story director.

When we execute a BT's node, the node can return three states: success, failure, or running (if the node's execution is spread over multiple frames, for instance, if it plays an animation). When the BT executor runs a tree, it starts from the root and executes every node in order, according to rules written in the nodes themselves.

A node can be of three types:

  • A task (a node without children), also called a leaf.
  • A decorator (a node with a single child)
  • A composite (a node with multiple children)

In general, leaves represent the Action that the characters can do or know (that is why they are commonly called an Action or Task); they may be actions such as GoToTarget...