Developing 2D Games with Unity : Independent Game Programming with C#

Follow a walkthrough of the Unity Engine and learn important 2D-centric lessons in scripting, working with image assets, animations, cameras, collision detection, and state management. In addition to the fundamentals, you'll learn best practices, helpful game-architectural patterns, and how to customize Unity to suit your needs, all in the context of building a working 2D game. While many books focus on 3D game creation with Unity, the easiest market for an independent developer to thrive in is 2D games. 2D games are generally cheaper to produce, more feasible for small teams, and more likely to be completed. If you live and breathe games and want to create them then 2D games are a great place to start. By focusing exclusively on 2D games and Unity’s ever-expanding 2D workflow, this book gives aspiring independent game developers the tools they need to thrive. Various real-world examples of independent games are used to teach fundamental concepts of developing 2D games in Unity, using the very latest tools in Unity’s updated 2D workflow. New all-digital channels for distribution, such as Nintendo eShop, XBox Live Marketplace, the Playstation Store, the App Store, Google Play, itch.io, Steam, and GOG.com have made it easier than ever to discover, buy, and sell games. The golden age of independent gaming is upon us, and there has never been a better time to get creative, roll up your sleeves, and build that game you’ve always dreamed about. Developing 2D Games with Unity can show you the way. What You'll Learn • Delve deeply into useful 2D topics, such as sprites, tile slicing, and the brand new Tilemap feature. • Build a working 2D RPG-style game as you learn. • Construct a flexible and extensible game architecture using Unity-specific tools like Scriptable Objects, Cinemachine, and Prefabs. • Take advantage of the streamlined 2D workflow provided by the Unity environment. • Deploy games to desktop Who This Book Is For Hobbyists with some knowledge of programming, as well as seasoned programmers interested in learning to make games independent of a major studio. Table of Contents 4 About the Author 13 About the Technical Reviewer 14 Acknowledgments 15 Preface 16 About This Book 18 Chapter 1: Games and Game Engines 20 Game Engines—What Are They? 20 The First Way to Build a House 23 The Second Way to Build a House 23 About the First Approach 24 About the Second Approach 24 In conclusion ... 25 Game Engines Historically 25 Game Engines Today 27 The Unity Game Engine 29 Summary 31 Chapter 2: Introduction to Unity 32 Install Unity 32 Configure Unity 33 On Disk 34 In the Cloud 34 The Script Editor: Visual Studio 36 Navigating the Unity Interface 37 Understanding the Different Window Views 37 Configure and Customize the Layout 41 The Transform Toolset 42 Handle Position Controls 44 Play, Pause, and Step Controls 45 Unity Project Structure 47 Unity Documentation 48 Summary 48 Chapter 3: Foundations 50 Game Objects: Our Container Entities 50 Entity-Component Design 52 Components: Building Blocks 54 Sprites 54 Animations 64 The Animator State Machine 68 Colliders 73 The Rigidbody Component 75 Tags and Layers 76 Tags 76 Layers 77 Sorting Layers 78 Introducing: Prefabs 82 Scripts: Logic for Components 84 State and Animations 94 More State Machines 94 Animation Parameters 97 Summary 109 Chapter 4: World Building 110 Tilemaps and Tile Palettes 110 Creating Tile Palettes 112 Painting with Tile Palettes 115 The Tile Palette 116 Working with Multiple Tilemaps 120 Graphics Settings 125 The Camera 126 Using Cinemachine 130 Installing Cinemachine in Unity 2017 130 Installing Cinemachine in Unity 2018 131 After Installing Cinemachine 132 Virtual Cameras 133 Cinemachine Confiner 139 Stabilization 144 Materials 148 Colliders and Tilemaps 149 Tilemap Collider 2D 149 Composite Colliders 152 Editing Physics Shapes 156 Summary 160 Chapter 5: Assembling the Nuts and Bolts 161 Character Class 161 Player Class 163 Focus on Prefabs 165 Create a Coin Prefab 165 Set Up the Circle Collider 2D 166 Set Up a Custom Tag 167 Layer-Based Collision Detection 169 Triggers and Scripting 172 Scriptable Objects 174 Creating a Scriptable Object 175 Build the Consumable Script 179 Assembling Our Item 180 Player Collisions 182 Creating a Heart Power-Up 183 Summary 191 Chapter 6: Health and Inventory 192 Creating a Health Bar 192 Canvas Objects 192 UI Elements 193 Building the Health Bar 193 Anchors 196 Adjusting the Anchor Points 198 UI Image Masks 201 Importing Custom Fonts 205 Adding Hit-Points Text 206 Scripting the Health Bar 209 Scriptable Object: HitPoints 209 Update the Character Script 210 Update the Player Script 211 Create the HealthBar Script 215 Configure the Health Bar Component 219 Inventory 223 Import the Inventory Slot Image 226 Configure the Inventory Slot 227 Configure the ItemImage 227 Configure the Background 228 Configure the Tray 229 Configure QtyText—the Quantity Text 230 Create the Prefabs 231 Build the Slot Script 232 Create the Inventory Script 235 Set-Up Properties 235 Instantiate the Slot Prefabs 237 Fill in the Start() Method 239 The AddItem Method 240 Update the Player Script 245 One Last Thing ... 246 Summary 248 Chapter 7: Characters, Coroutines, and Spawn Points 249 Create a Game Manager 249 Singletons 250 Creating the Singleton 251 Build a GameManager Prefab 254 Spawn Points 254 Build a Spawn Point Prefab 257 Configure the Player Spawn Point 261 Spawn the Player 262 In Summary 264 A Spawn Point for Enemies 265 Camera Manager 267 Using the Camera Manager 269 Character Class Design 272 The Virtual Keyword 272 The Enemy Class 273 Refactoring 273 The Internal Access Modifier 274 Coroutines 275 Invoking Coroutines 276 Pausing or “Yielding” Execution 276 A Complete Coroutine 276 Coroutines with Time Intervals 277 The Abstract Keyword 277 Implementing the Enemy Class 279 The DamageCharacter() method 279 ResetCharacter() 282 Calling ResetCharacter() in OnEnable() 283 KillCharacter() 283 Updating the Player Class 283 Refactoring Prefab Instantiation 285 Review 286 Using What We’ve Built 287 OnCollisionEnter2D 288 OnCollisionExit2D 289 Configure the Enemy Script 290 Summary 291 Chapter 8: Artificial Intelligence and Slingshots 292 The Wander Algorithm 292 Getting Started 293 Create the Wander Script 294 Wander Variables 295 Build Out Start() 297 The Wander Coroutine 298 Choosing a New Endpoint 300 Angles to Radians to Vectors! 302 Enemy Walk Animation 302 The Move() Coroutine 306 Configure Wander Script 309 OnTriggerEnter2D() 310 OnTriggerExit2D() 312 Gizmos 314 Self-Defense 317 Classes Needed 318 Ammo Class 318 Import the Assets 319 Add Components, Set Layers 319 Update the Layer Collision Matrix 320 Build the Ammo Script 321 Before We Forget ... Make the AmmoObject Prefab 323 Object Pooling 323 Building the Weapon Class 325 Stubbing-Out Methods 328 The SpawnAmmo Method 330 The Arc Class and Linear Interpolation 332 Screen Points and World Points 335 The FireAmmo Method 336 Configure the Weapon Script 338 Arcing 339 Animating the Slingshot 341 Animation and Blend Trees 341 Blend Trees 342 Clean Up the Animator 343 Build the Walking Blend Tree 344 Layers, All the Way Down 347 A Note About Blend Types 348 Animation Parameters 348 Use the Parameters 350 Ok, but Why ? 352 Loop Time 354 Create the Transitions 354 Updating the Movement Controller 355 Import the Fight Sprites 357 Create Animation Clips 357 Build the Fighting Blend Tree 359 Exit Time 361 Update the Weapon Class 362 Add the Variables 362 Start() 364 Update Update() 365 Determining Direction 365 The Slope Method 368 Calculate the Slopes 369 Comparing y-Intercepts 370 HigherThanNegativeSlopeLine() 371 The GetQuadrant() method 372 The UpdateState() Method 374 Flicker When Damaged 377 Update the Player and Enemy Classes 378 Building for Platforms 379 Exiting the Game 382 Summary 382 What’s Next 383 Communities 383 Learn More 384 Where to Find Help 384 Game Jams 385 News and Articles 386 Games and Assets 386 Beyond! 386 Index 388 Front Matter ....Pages i-xxii Games and Game Engines (Jared Halpern)....Pages 1-12 Introduction to Unity (Jared Halpern)....Pages 13-30 Foundations (Jared Halpern)....Pages 31-90 World Building (Jared Halpern)....Pages 91-141 Assembling the Nuts and Bolts (Jared Halpern)....Pages 143-173 Health and Inventory (Jared Halpern)....Pages 175-231 Characters, Coroutines, and Spawn Points (Jared Halpern)....Pages 233-275 Artificial Intelligence and Slingshots (Jared Halpern)....Pages 277-372 Back Matter ....Pages 373-383