Beginning Android 3D Game Development Part-1

Chapter 1

Beginning Android 3D Game Development Part-1

Let’s Meet the Android

Android mobile phones dominate the mobile smartphone market, surpassing even Apple’s iPhone.

There are hundreds of millions of mobile phones using the Android operating system in over

190 countries around the world. Every day, a million new users begin using their Android phones to

surf the Web, to e-mail friends, and to download apps and games. In fact, in the Google Play Store

alone, there are 1.5 billion downloads per month of Android games and applications. If you include

other web sites that offer Android games and apps for sale, such as Amazon App store for Android,

then the number is even higher.

In this chapter, you will learn about the Android Software Development Kit (SDK). You will learn how

to set up the Android development environment. You will also learn about the major components

of this environment, such as Eclipse. We then go through the creation and deployment of a simple

“Hello World” program for Android, to both a virtual Android emulator program and also a real

Android device.

Overview of Android

The Android operating system is a widely used operating system available on mobile phones and

tablets. It is even used on a video game console called the Ouya. Android phones range from

expensive phones that require a contract to inexpensive prepaid phones that do not require any

contract. Developing programs for the Android platform does not require any developer’s fees,

unlike Apple mobile devices, which require yearly fees in order to even be able to run your program

on their devices. A good working prepaid no-contract Android phone that can develop 3D games

using OpenGL ES 2.0 can be bought on Amazon.com for as little as $75–$100 with free shipping.

Overview of the Android SDK

This section discusses the Android SDK. Development system requirements and important individual

pieces of the SDK, such as the SDK Manager, Android Virtual Device Manager, and the actual

Android emulator will be covered.

Android Software Development Kit (SDK) Requirements

Android development can be done on a Windows PC, Mac OS machine, or a Linux machine. The exact

operating system requirements are as follows:

Operating Systems:

 Windows XP (32-bit), Vista (32- or 64-bit), or Windows 7 (32- or 64-bit)

 Mac OS X 10.5.8 or later (x86 only)

 Linux (tested on Ubuntu Linux, Lucid Lynx)

 GNU C Library (glibc) 2.7 or later is required.

 On Ubuntu Linux, version 8.04 or later is required.

 64-bit distributions must be capable of running 32-bit applications.

Developing Android programs also requires installation of the Java Development Kit. Java Development

Kit requirements are JDK 6 or later and are located at www.oracle.com/technetwork/java/javase/

downloads/index.html.

If you are using a Mac, then Java may already be installed.

The Eclipse IDE program modified with the Android Development Tools (ADT) plug-in forms the basis

for the Android development environment. The requirements for Eclipse are as follows:

 Eclipse 3.6.2 (Helios) or greater located at http://eclipse.org

 Eclipse JDT plug-in (included in most Eclipse IDE packages)

 Android Development Tools (ADT) plug-in for Eclipse located at

http://developer.android.com/tools/sdk/eclipse-adt.html

Notes Eclipse 3.5 (Galileo) is no longer supported with the latest version of ADT. For the latest information

on Android development tools, go to http://developer.android.com/tools/index.html.

Android SDK Components Overview

The different components of the Android SDK are the Eclipse program, the Android SDK Manager,

and the Android Virtual Device Manager and emulator. Let’s look at each in more detail.

Eclipse with Android Development Tools Plug-in

The actual part of the Android SDK that you will spend most of your time dealing with is a program

called Eclipse, which is customized specifically for use with Android through the ADT software

plug-in. You will enter new code, create new classes, run programs on the Android emulator and on

real devices from this program. On older, less capable computers, the emulator may run so slowly that the best option would be running the program on an actual Android device. Because we are

dealing with CPU-intensive 3D games in this book, you should use an actual Android device to run

the example projects (see Figure 1-1). 

Figure 1-1. Eclipse with Android Development Tools plug-ins

Android SDK Manager

The Android SDK Manager allows you to download new Android platform versions and tools through

its interface. Current tools and platform versions that are installed are also displayed. For example,

in Figure 1-2, the Android 2.2 platform has already been installed and is ready for use for development.

This means that you can compile your source code to target this platform. Android Virtual Device

The Android SDK also supports a virtual device emulator (see Figure 1-3). In many instances, you will

be able to run your Android programs on a software emulator on your development system rather

than an actual device. However, this works best for non-graphic intensive applications. Because

this book deals with 3D games, we will not be using this software emulator but an actual Android

device. The Android Virtual Device Manager allows you to create new virtual Android devices, edit

existing Android devices, delete existing devices, and start up an existing virtual Android device.

Figure 1-3 indicates that there is a valid virtual Android device named “Android22,” which emulates

the 2.2 version of the Android operating system (API Level 8) and simulates the ARM CPU type. The

2.2 version of the Android operating system is important because it is the first version that supports

OpenGL ES 2.0, which we will be using in this book to develop our 3D graphics. OpenGL is the

graphics system that allows the programmer to create 3D graphics on the Android platform. It is

designed to be hardware-independent. That is, OpenGL graphics commands are designed to be the

same across many different hardware platforms, such as PC, Mac, Android, etc. The OpenGL 2.0

version of OpenGL is the first version of OpenGL that includes programmable vertex and fragment

shaders. OpenGL ES is a subset of regular OpenGL and contains fewer features. Figure 1-4 depicts the actual emulator after it is launched. The emulator depicted is the one for

version 2.2 of the Android operating system.

How to Set Up for Development

First, you need to download and install the Java Development Kit Version 6 or greater. The Android

development environment requires this as a prerequisite. After you verify that it is installed and

working, then you will have to install the main components of the Android SDK.

The quickest and easiest way to do this is to download the ADT Bundle located at

http://developer.android.com/sdk/index.html under the “Download for Other Platforms” section. The ADT Bundle is a downloadable zip file that contains a special version of Eclipse with the Android

Development Tools plug-in, the Android Virtual Device Manager, the SDK Manager and tools, as well

as the latest Android platform, and the latest Android system image for the Android emulator. All you

have to do to install this ADT Bundle is to create a new directory and unzip the file into it. You can

use a free tool such as 7-Zip to uncompress the file. After doing this, you can execute the new

ADT Integrated Development Environment by executing the eclipse.exe file located in the Eclipse

directory under the main bundle directory.

Note 7-Zip can be downloaded at www.7-zip.org.

Android Development Tools Integrated Development Environment

(IDE) Overview

The Eclipse IDE consists of several important sections that I will discuss here. The important

sections are the Package Explorer window, the Source Code Area window, the Outline window, and

the Messages windows, including a window that outputs programmer-specified debug messages

that is called the LogCat window. There are other Messages windows available, but they are less

important and won’t be covered in this section.

Package Explorer

When you start on a new Android programming project, you will create a new package for it. In Eclipse,

there is a window called Package Explorer, located by default on the left-hand side. This window lists

all the Android packages located in the current work space. For example, Figure 1-5 lists packages

such as “AndroidHelloWorld,” “AndroidHelloWorldTest,” and “ApiDemos.”

You can also expand a package so that you can access all the files related to that package by

clicking the “plus” symbol next to the package name. The Java source code files are located in the

“src” directory, and the project-related resources, such as textures, 3D models, etc., are located in

the “res” (short for resources) directory. Double-click a source code file or resource file to bring it

up for viewing inside Eclipse. Source files can also be expanded so that you can get an overview

of the class’s variables and functions. You can double-click a variable or function to go to that

variable or function within Eclipse’s source view window. In Figure 1-6, there is only one function

in the “AndroidHelloWorldActivity” class, which is “onCreate.” Finally, every Android package has

an AndroidManifest.xml file that defines such things as what permissions are needed to run the

program, program-specific information such as version number, program icon, and program name,

as well as what minimum Android operating system is needed to run the program.

Source Code Area

By default, in the middle of Eclipse is the Java source code display window. Each different Java source

code or .xml file is displayed here in its own tab (see Figure 1-7).

Notice that at the end of the last tab, there is a “➤” followed by “4.” What this means is that there

are four hidden files not shown. You can access these files by clicking the “➤4” region to bring up

a complete list of files. Files listed in boldface type are not shown, and you can select these for

viewing by highlighting them with your mouse pointer and left-clicking them (see Figure 1-8).

Outline

The Outline window in Eclipse is located by default on the right side, and it lists the variables and

functions for the class that is selected in the source code window. You can easily jump to the

corresponding class variable or class function in the source code window by clicking the variable or

function in the Outline window (see Figure 1-9).

In Figure 1-9, class variables or “fields” are listed first, followed by class functions. Some examples

of class variables are HIGH_SCORES, m_BackGroundTexture, and m_Dirty. Some examples of class

functions are FindEmptySlot(), RenderTitle(), and SortHighScoreTable().

Dalvik Debug Monitor Server (DDMS)

Eclipse with the ADT plug-in also provides a way to easily interface with actual Android hardware

through the Dalvik Debug Monitor Server or DDMS. The button to access the DDMS is on the right

upper corner of the Eclipse IDE. Click this button to switch views to the DDMSIn the DDMS view, you can look at the actual directories and files on the Android device by using the

File Explorer tab located on the right-hand side of the view. Figure 1-11 illustrates this. On the left side, if you have an actual physical Android device connected via the USB port, the

device is displayed in the Devices tab, as shown in Figure 1-12. Also notice the camera icon at the upper right-hand corner of the Devices window. If you click this

button, then you capture a screenshot of what is currently on the Android device (see Figure 1-13).

From this pop-up window, you can rotate the image and save the image, if you so desire. This is a good

way to get screenshots for promotional images when it is time to market your application to end users.

LogCat Window

At the bottom of the Eclipse IDE there are by default a few rectangular windows. One of the more

important ones is called the LogCat window, and this window displays debug and error messages

that are directly coming from a program that is running on the Android device that is attached to your

computer via a USB cable.

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