Book Image

Game Development Patterns with Unity 2021 - Second Edition

By : David Baron
Book Image

Game Development Patterns with Unity 2021 - Second Edition

By: David Baron

Overview of this book

This book is written for every game developer ready to tackle the bigger picture and start working with advanced programming techniques and design patterns in Unity. Game Development Patterns with Unity 2021 is an introduction to the core principles of reusable software patterns and how to employ them to build components efficiently. In this second edition, you'll tackle design patterns with the help of a practical example; a playable racing game prototype where you’ll get to apply all your newfound knowledge. Notable updates also include a game design document (GDD), a Unity programming primer, and the downloadable source code of a complete prototype. Your journey will start by learning about overall design of the core game mechanics and systems. You’ll discover tried-and-tested software patterns to code essential components of a game in a structured manner, and start using classic design patterns to utilize Unity's unique API features. As you progress, you'll also identify the negative impacts of bad architectural decisions and understand how to overcome them with simple but effective practices. By the end of this Unity book, the way you develop Unity games will change – you’ll adapt a more structured, scalable, and optimized process that will help you take the next step in your career.
Table of Contents (22 chapters)
Sections 1: Fundamentals
Section 2: Core Patterns
Section 3: Alternative Patterns
About Packt

An overview of the State pattern

We use the State design pattern to implement a system that will permit an object to change its behavior based on its internal state. Thus, a change of context will bring on a change of behavior.

The State pattern has three core participants in its structure:

  • The Context class defines an interface that permits a client to request a change in the internal state of an object. It also holds a pointer to the current state.
  • The IState interface establishes an implementation contract for the concrete state classes.
  • The ConcreteState classes implement the IState interface and expose a public method named handle() that the Context object can call to trigger the state's behavior.

Let's now review a diagram of this pattern definition, but in the context of an actual implementation:

Figure 5.1 – UML diagram of the State pattern

To update an object's state, the client can set the expected state through the Context...