Game Development with Swift E-Book

Stephen Haney

• Herausgeber: Packt Publishing
• Kategorie: Fachliteratur
• Sprache: Englisch

Seitenzahl: 210

Veröffentlichungsjahr: 2015

Beschreibung

If you wish to create and publish fun iOS games using Swift, then this book is for you. You should be familiar with basic programming concepts. However, no prior game development or Apple ecosystem experience is required.

Leseprobe

Table of Contents

Game Development with Swift

Credits

About the Author

About the Reviewers

www.PacktPub.com

Support files, eBooks, discount offers, and more

Why subscribe?

Free access for Packt account holders

Preface

What this book covers

What you need for this book

Who this book is for

Conventions

Reader feedback

Customer support

Downloading the example code

Downloading the color images of this book

Errata

Piracy

Questions

1. Designing Games with Swift

Why you will love Swift

Beautiful syntax

Interoperability

Strong typing

Smart type inference

Automatic memory management

An even playing field

Are there any downsides to Swift?

Less resources

Operating system compatibility

Prerequisites

What you will learn in this book

Embracing SpriteKit

Reacting to player input

Structuring your game code

Building UI/menus/levels

Integrating with Game Center

Maximizing fun

Crossing the finish line

Further research

Marketing and monetizing your game

Making games specifically for the desktop on OSX

Setting up your development environment

Introducing Xcode

Creating our first Swift game

Navigating our project

Exploring the SpriteKit Demo

Examining the demo code

Cleaning up

Summary

2. Sprites, Camera, Actions!

Sharpening our pencils

Checkpoint 2- A

Drawing your first sprite

Building a SKSpriteNode class

Adding animation to your Toolkit

Sequencing multiple animations

Recapping your first sprite

The story on positioning

Alignment with anchor points

Adding textures and game art

Downloading the free assets

More exceptional art

Drawing your first textured sprite

Adding the bee image to your project

Loading images with SKSpriteNode

Designing for retina

The ideal asset approach

My solution for now

Hands-on with retina in SpriteKit

Organizing your assets

Exploring Images.xcassets

Collecting art into texture atlases

Updating our bee node to use the texture atlas

Iterating through texture atlas frames

Putting it all together

Centering the camera on a sprite

Creating a new world

Checkpoint 2-B

Summary

3. Mix in the Physics

Laying the foundation

Following protocol

Reinventing the bee

The icy tundra

Another way to add assets

Adding the Ground class

Tiling a texture

Running wire to the ground

A wild penguin appears!

Renovating the GameScene class

Exploring the physics system

Dropping like flies

Solidifying the ground

Checkpoint 3-A

Exploring physics simulation mechanics

Bee meets bee

Impulse or force?

Checkpoint 3-B

Summary

4. Adding Controls

Retrofitting the Player class for flight

The Beekeeper

Updating the Player class

Moving the ground

Assigning a physics body to the player

Creating a physics body shape from a texture

Polling for device movement with Core Motion

Implementing the Core Motion code

Checkpoint 4-A

Wiring up the sprite onTap events

Implementing touchesBegan in the GameScene

Larger than life

Teaching our penguin to fly

Listening for touches in GameScene

Fine-tuning gravity

Spreading your wings

Improving the camera

Pushing Pierre forward

Tracking the player's progress

Looping the ground

Checkpoint 4-B

Summary

5. Spawning Enemies, Coins, and Power-ups

Introducing the cast

Adding the power-up star

Locating the art assets

Adding the Star class

Adding a new enemy – the mad fly

Locating the enemy assets

Adding the MadFly class

Another terror – bats!

Adding the Bat class

The spooky ghost

Adding the Ghost class

Guarding the ground – adding the blade

Adding the Blade class

Adding the coins

Creating the coin classes

Organizing the project navigator

Testing the new game objects

Checkpoint 5-A

Preparing for endless flight

Summary

6. Generating a Never-Ending World

Designing levels with the SpriteKit scene editor

Separating level data from game logic

Using empty nodes as placeholders

Encounters in endless flying

Creating our first encounter

Integrating scenes into the game

Checkpoint 6-A

Spawning endless encounters

Building more encounters

Updating the EncounterManager class

Storing metadata in SKSpriteNode userData property

Wiring up EncounterManager in the GameScene class

Spawning the star power-up at random

Checkpoint 6-B

Summary

7. Implementing Collision Events

Learning the SpriteKit collision vocabulary

Collision versus contact

Physics category masks

Using category masks in Swift

Adding contact events to our game

Setting up the physics categories

Assigning categories to game objects

The player

The ground

The star power-up

Enemies

Coins

Preparing GameScene for contact events

Viewing console output

Testing our contact code

Checkpoint 7-A

Player health and damage

Animations for damage and game over

The damage animation

The game over animation

Collecting coins

The power-up star logic

Checkpoint 7-B

Summary

8. Polishing to a Shine – HUD, Parallax Backgrounds, Particles, and More

Adding a heads-up display

Parallax background layers

Adding the background assets

Implementing a background class

Wiring up backgrounds in the GameScene class

Checkpoint 8-A

Harnessing SpriteKit's particle system

Adding the circle particle asset

Creating a SpriteKit Particle File

Configuring the path particle settings

Adding the particle emitter to the game

Granting safety as the game starts

Checkpoint 8-B

Summary

9. Adding Menus and Sounds

Building the main menu

Creating the menu scene and menu nodes

Launching the main menu when the game starts

Wiring up the START GAME button

Adding the restart game menu

Extending the HUD

Wiring up GameScene for game over

Informing the GameScene class when the player dies

Implementing touch events for the restart menu

Checkpoint 9-A

Adding music and sound

Adding the sound assets to the game

Playing background music

Playing sound effects

Adding the coin sound effect to the Coin class

Adding the power-up and hurt sound effects to the Player class

Playing a sound when the game starts

Checkpoint 9-B

Summary

10. Integrating with Game Center

Registering an app with iTunes Connect

Configuring Game Center

Creating a test user

Authenticating the player's Game Center account

Opening Game Center in our game

Checkpoint 10-A

Adding a leaderboard of high scores

Creating a new leaderboard in iTunes Connect

Updating the leaderboard from the code

Adding an achievement

Creating a new achievement in iTunes Connect

Updating achievements from the code

Checkpoint 10-B

Summary

11. Ship It! Preparing for the App Store and Publication

Finalizing assets

Adding app icons

Designing the launch screen

Taking screenshots for each supported device

Finalizing iTunes Connect information

Configuring pricing

Uploading our project from Xcode

Submitting for review in iTunes Connect

Summary

Index

Game Development with Swift

Game Development with Swift

Copyright © 2015 Packt Publishing

All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, without the prior written permission of the publisher, except in the case of brief quotations embedded in critical articles or reviews.

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First published: July 2015

Production reference: 1170715

Published by Packt Publishing Ltd.

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Credits

Author

Stephen Haney

Reviewers

Antonio Bello

Vladimir Pouzanov

Kevin Smith

Anil Varghese

Commissioning Editor

Edward Bowkett

Acquisition Editor

Reshma Raman

Content Development Editors

Prachi Bisht

Mamata Walkar

Technical Editor

Saurabh Malhotra

Copy Editors

Janbal Dharmaraj

Kevin McGowan

Rashmi Sawant

Project Coordinator

Sanjeet Rao

Proofreader

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Indexer

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Production Coordinator

Nitesh Thakur

Cover Work

Nitesh Thakur

About the Author

Stephen Haney began his programming journey at the age of 8 on a dusty, ancient laptop using BASIC. He has been fascinated with building software and games ever since. Now well versed in multiple languages, he most enjoys programming as a creative outlet. He believes that indie game development is an art form: an amazing combination of visual, auditory, and psychological challenges, rewarding to both the player and the creator.

He enjoyed writing this book and sincerely hopes that it directly furthers your career or hobby.

Thank you to my beautiful girlfriend, Kayla, for her patience and advice.

About the Reviewers

Antonio Bello is a veteran software developer, who started writing code when memory was measured in bytes instead of gigabytes and storage was an optional add-on. Over his professional career, he has worked with several languages and technologies, in many cases, following a "learning by using" approach.

Today, he loves developing iOS Apps and their respective backends, favoring Swift over Objective C but loving both languages.

Vladimir Pouzanov is a systems engineer and an embedded enthusiast. He has spent countless hours hacking different mobile hardware, porting Linux to various devices on which it was not supposed to be run, and toying outside the iOS sandbox. He has been a professional iOS consultant and has been developing applications based on iOS since the first Apple iPhones were available. Later on, he switched his professional interest to systems engineering and cloud computing, but he still keeps a close eye on the mobile and embedded world.

I'd like to thank my wife for her amazing support while I was working on the review, sharing my attention between her, our daughter, and the book.

Kevin Smith is a founder and mobile developer. He released his first iPhone App in 2009. After the success of his first few apps, he founded App Press to help others build mobile apps. Through App Press, he has worked on and released countless award-winning iOS and Android apps.

Anil Varghese is a software engineer from Kerala, India, with extensive experience in iOS application development. He constantly strives to learn new technologies and better and faster ways of solving problems. He always finds time to help his fellow programmers and is an active member of developer communities, such as Stack Overflow.

You can reach him at <[email protected]> and http://anilvarghese.strikingly.com.

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Preface

There has never been a better time to be a game developer. The App Store provides a unique opportunity to distribute your ideas to a massive audience. Now, Swift has arrived to bolster our toolkit and provide a smoother development experience. Swift is new, but is already hailed as an excellent, well-designed language. Whether you are new to game development or looking to add to your expertise, I think you will enjoy making games with Swift.

My goal in writing this book is to share a fundamental knowledge of Swift and SpriteKit. We will work through a complete example game so that you learn every step of the Swift development process. Once you finish this text, you will be comfortable designing and publishing your own game ideas to the App Store, from start to finish.

Please reach out with any questions and share your game creations:

E-mail: <[email protected]>

Twitter: @sdothaney

The first chapter explores some of Swift's best features. Let's get started!

What this book covers

Chapter 1, Designing Games with Swift, introduces you to best features on Swift, helps you set up your development environment, and launches your first SpriteKit project.

Chapter 2, Sprites, Camera, Actions!, teaches you the basics of drawing and animating with Swift. You will draw sprites, import textures into your project, and center the camera on the main character.

Chapter 3, Mix in the Physics, covers the physics simulation fundamentals: physics bodies, impulses, forces, gravity, collisions, and more.

Chapter 4, Adding Controls, explores various methods of mobile game controls: device tilt and touch input. We will also improve the camera and core gameplay of our example game.

Chapter 5, Spawning Enemies, Coins, and Power-ups, introduces the cast of characters we will use in our example game and shows you how to create custom classes for each NPC type.

Chapter 6, Generating a Never-Ending World, explores the SpriteKit scene editor, builds encounters for the example game, and creates a system to loop encounters endlessly.

Chapter 7, Implementing Collision Events, delves into advanced physics simulation topics and adds custom events when sprites collide.

Chapter 8, Polishing to a Shine – HUD, Parallax Backgrounds, Particles, and More, adds the extra features that make every great game shine. Create parallax backgrounds, learn about SpriteKit's particle emitters, and add a heads-up display overlay to your games.

Chapter 9, Adding Menus and Sounds, builds a basic menu system and illustrates two methods of playing sounds in your games.

Chapter 10, Integrating with Game Center, links our example game to the Apple Game Center for leaderboards, achievements, and friendly challenges.

Chapter 11, Ship It! Preparing for the App Store and Publication, covers the essentials of packaging your game and submitting it to the App Store.

What you need for this book

This book uses the Xcode IDE Version 6.3.2 (Swift 1.2). If you use a different version of Xcode, you will likely encounter syntax differences; Apple is constantly upgrading Swift's syntax.

Visit https://developer.apple.com/xcode/ to download Xcode.

You will need an Apple developer account to integrate your apps with the Game Center and to submit your games to the App Store.

Who this book is for

If you wish to create and publish fun iOS games using Swift, then this book is for you. You should be familiar with basic programming concepts such as classes, types, and functions. However, no prior game development or Apple ecosystem experience is required. Additionally, experienced game programmers will find this book useful as they transition into game development with Swift.

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Chapter 1. Designing Games with Swift

Apple's new language has arrived at the perfect time for game developers. Swifthas the unique chance to be something special; a revolutionary tool for app creators. Swift is the gateway for developers to create the next big game on the Apple ecosystem. We have only started to explore the wonderful potential of mobile gaming and Swift is the modernization we need for our toolset. Swift is fast, safe, current, and attractive to developers coming from other languages. Whether you are new to the Apple world, or a seasoned veteran of Objective-C, I think you will enjoy making games with Swift.

Note

Apple's website states, "Swift is a successor to the C and Objective-C languages."

My goal in this book is to guide you step-by-step through the creation of a 2D game for iPhones and iPads. We will start with installing the necessary software, work through each layer of game development, and ultimately publish our new game to the App Store.

We will also have some fun along the way! We aim to create an endless flyer game featuring a magnificent flying penguin named Pierre. What is an endless flyer? Picture hit games like iCopter, Flappy Bird, Whale Trail, Jetpack Joyride, and many more – the list is quite long.

Endless flyer games are popular on the App Store and the genre necessitates that we cover many reusable components of 2D game design; I will show you how to modify our mechanics to create many different game styles. My hope is that our demo project will serve as a template for your own creative works. Before you know it, you will be publishing your own game ideas using the techniques we explore together.

The topics in this chapter include:

Why you will love SwiftWhat you will learn in this bookSetting up your development environmentCreating your first Swift game

Why you will love Swift

Swift, as a modern programming language, benefits from the collective experience of the programming community; it combines the best parts of other languages and avoids poor design decisions. Here are a few of my favorite Swift features.

Beautiful syntax

Swift's syntax is modern and approachable, regardless of your existing programming experience. Apple balanced syntax with structure to make Swift concise and readable.

Interoperability

Swift can plug directly into your existing projects and run side-by-side with your Objective-C code.

Strong typing

Swift is a strongly typed language. This means the compiler will catch more bugs at compile time – instead of when your users are playing your game! The compiler will expect your variables to be of a certain type (int, string, and so on) and will throw a compile-time error if you try to assign a value of a different type. While this may seem rigid if you are coming from a weakly typed language, the added structure results in safer, more reliable code.

Smart type inference

To make things easier, type inference will automatically detect the types of your variables and constants based upon their initial value. You do not need to explicitly declare a type for your variables. Swift is smart enough to infer variable types in most expressions.

Automatic memory management

As the Apple Swift developer guide states, "memory management just works in Swift." Swift uses a method called Automatic Reference Counting (you will see it referred to as ARC) to manage your game's memory usage. Besides a few edge cases, you can rely on Swift to safely clean up and turn off the lights.

An even playing field

One of my favorite things about Swift is how quickly the language is gaining mainstream adoption. We are all learning and growing together and there is a tremendous opportunity to break new ground.

Are there any downsides to Swift?

Swift is a very enjoyable language, but we should consider these two issues when starting a new project.

Less resources

Given Swift's age, it is certainly more difficult to find answers to common questions through Internet searches. Objective-C has many years' worth of discussion and answers on helpful forums like Stack Overflow. This issue improves every day as the Swift community continues to develop.

Operating system compatibility

Swift projects will run on iOS7 and higher, and OSX 10.9 and higher. Swift is the wrong choice if, in a rare case, you need to target a device running an older operating system.

Prerequisites

I will strive to make this text easy to comprehend for all skill levels:

I will assume you are brand new to Swift as a languageThis book requires no prior game development experience, though it will helpI will assume you have a fundamental understanding of common programming concepts

What you will learn in this book

By the end of this book, you will be capable of creating and publishing your own iOS games. You will know how to combine the techniques we learn to create your own style of game and you will be well prepared to dive into more advanced topics with a solid foundation in 2D game design.

Embracing SpriteKit

SpriteKit is Apple's 2D game development framework and your main tool for iOS game design. SpriteKit will handle the mechanics of our graphics rendering, physics, and sound playback. As far as game development frameworks go, SpriteKit is a terrific choice. It is built and supported by Apple and thus integrates perfectly with Xcode and iOS. You will learn to be highly proficient with SpriteKit – we will use it exclusively in our demo game.

We will learn to use SpriteKit to power the mechanics of our game:

Animate our player, enemies, and power-upsPaint and move side scrolling environmentsPlay sounds and musicApply physics-like gravity and impulses for movementHandle collisions between game objects

Reacting to player input

The control schemes in mobile games must be inventive. Mobile hardware forces us to simulate traditional controller inputs, such as directional pads and multiple buttons on the screen. This takes up valuable visible area and provides less precision and feedback than with physical devices. Many games operate with only a single input method; a single tap anywhere on the screen. We will learn how to make the best of mobile input and explore new forms of control by sensing device motion and tilt.