Introduction
Welcome to Android Game Recipes. This book is specifically written to help you with many of the common problems that you may have encountered while in the process of creating a game for the Android platform. Android game development can be a fun, enjoyable, and rewarding process; but it is not without its pitfalls. There always seem to be problems that come up during the development process that are difficult to find solutions to. My hope is that this book can provide you with those solutions.
I have created multiple games for Android, and have encountered many problems while doing so. My experiences, and the solutions I have found, are compiled into 17 chapters, each separated by major topic. Outlined as follows are the chapters in this book and a quick summary of what will be covered in each.
Chapter 1: Getting Started. This chapter covers the skills and software that you need to make the most of this book. Chapter 1 also includes a quick introduction to Android gaming and OpenGL ES versions 1, and 2 / 3.
Chapter 2: Loading an Image. There are different situations that may call for an image to be loaded either with or without OpenGL ES. If you are creating a splash screen you may not want to use OpenGL. The recipes in this chapter help you create a splash screen without using OpenGL.
Chapter 3: The Splash Screen. Here you’ll find solutions to common problems in creating splash screens. These problems can include loading the screen image, transitions between multiple images, and loading the game after the splash screen.
Chapter 4: The Menu Screen. In this chapter, you’ll learn solutions to common menu screen problems, such as creating buttons, loading options, locking screen rotation, and detecting screen resolution.
Chapter 5: Reading Player Input. The recipes in this chapter solve problems related to reading player input during the game, such as touch screen input, multi-touch, and gestures.
Chapter 6: Loading a SpriteSheet. Being able to load a spritesheet is essential in creating a game. This chapter contains solutions for loading spritesheet images, animating multiple spritesheet images, and storing spritesheets.
Chapter 7: Scrolling a Background. Key to realism, Chapter 7 helps you solve issues related to scrolling a background image on the screen, such as loading the image to the screen and changing the scroll speed.
Chapter 8: Scrolling Multiple Backgrounds. In this chapter you’ll encounter recipes for how to scroll multiple background images to give the appearance of a foreground, middleground, and distance.
Chapter 9: Syncing a Background to Character Movement. In this chapter you’ll find solutions for changing the direction and speed of the background movement in relationship to the movement of the character.
Chapter 10: Building a Level Using Tiles. You’ll learn how to create levels for side-scrolling and platform games from graphic tiles. Using repeatable tiles is a tried and tested way to create game levels.
Chapter 11: Moving a Character. This covers problems that could arise when trying to animate a playable character, everything from walking, to running, to jumping and fighting.
Chapter 12: Moving an Enemy. Like Chapter 11, this chapter also discusses moving characters across the screen. However, this chapter focuses more on the specific problems encountered when creating AI based (non-playable) characters, such as moving on a predetermined path.
Chapter 13: Moving a Character with Obstacles. Most games do not have a smooth surface for which to play. That is, many game levels contain obstacles and inclines that the player needs to navigate. In this chapter you’ll encounter recipes for how to let your playable character navigate these obstacles.
Chapter 14: Firing Weapons. In this chapter you’ll learn how to fire or throw weapons. There are specific problems that need to be addressed when animating projectiles that include animation and the calculation of trajectories.
Chapter 15: Collision Detection. A key topic in game development, this covers the complex issue of collision detection. You’ll find recipes for how to detect and react to interactions between onscreen (in-game) objects.
Chapter 16: Keeping Score. One way for a player to track their process in a game is through a score. The solutions in chapter 16 help you compile a gamer’s score and write that score to the screen.
Chapter 17: Keeping Time. Some games are time based, or contain time based levels and challenges. Chapter 17 covers solutions for how to implement and track the expiration of time for marshaling in-game action.