Chapter 1. Getting Started With Corona SDK

Before we jump right into coding some simple games, we need to install and run the necessary programs that will make our applications come to life. Corona SDK is primarily a 2D development engine. If you've had experience developing for iOS or Android, you will find the experience working with Corona refreshing and simple to use. In no time you'll be creating finished products to distribute on the iPhone App Store and Google Play Store.

In this chapter, we will:

Set up Corona SDK on Mac OS X and Windows
Install Xcode for Mac OS X
Create a Hello World program in two lines
Add devices in the iOS Provisioning Portal
Load an application to an iOS device
Load an application to an Android device

Downloading and installing Corona

You have the option of choosing the Mac OS X or Microsoft Windows operating system to develop on. Keep in mind the following system requirements required to run the program.

If you are installing Corona for Mac OS X, be sure that your system is as follows:

Mac OS® X 10.6 or later
An Intel-based system that runs Snow Leopard or Lion
64-bit CPU (Core 2 Duo)
An OpenGL 1.4 or higher graphics system

If you are running Microsoft Windows, be sure that your system is as follows:

Windows 7, Vista, or XP operating system
1 GHZ processor (recommended)
38 MB of disk space (minimum)
1 GB of RAM (minimum)
OpenGL 1.3 or higher graphics system (available in most modern Windows systems)

Time for action – setting up and activating Corona on Mac OS X

Let's begin by setting up Corona SDK on our desktop.

If you haven't downloaded the SDK, please do so at: http://www.anscamobile.com/corona/. You will have to register as a user before you can access the SDK.
The file extension for any Mac program should end in .dmg, otherwise known as an Apple disk image. Once you've downloaded the disk image, double-click on the disk image file to mount it. The name should be similar to CoronaSDK.dmg.
Once it is loaded, you should see the mounted disk image folder as shown in the following screenshot:
Next, drag the CoronaSDK folder into the Applications folder. This will copy the contents of the Corona folder into /Applications. You will be prompted to enter an administrator password if you are not the main administrator of the account. You will be able to see the CoronaSDK folder in /Applications once it has been successfully installed.
For easy access to the folder's contents, create an alias by dragging the CoronaSDK folder to the Dock of your Mac desktop.
First time Corona SDK users will have to perform a quick and easy one-time authorization process before it canbe accessible.
Note
You must be connected to the Internet to complete the authorization process.
Launch the Corona Simulator in the SDK folder.
Assuming this is your first time, you will be presented with an End-user License Agreement (EULA). Once you have accepted the agreement, enter the e-mail you used to register for Corona and password to activate the SDK. Otherwise, click Register to create an account.
Note
If you register with Corona as a trial user, there is no fee to develop on iOS and/or Android devices. Developers that would like to publish their applications on the App Store or Google Play need to purchase the Corona SDK subscription on the website in order to do so at: http://www.anscamobile.com/corona/.
Upon successful login, you will get a confirmation dialog to show that the SDK is ready to use as shown in the following screenshot:
Click on the Continue button and you'll be presented with the Welcome to Corona screen as shown in the following screenshot:

What just happened?

Setting up Corona SDK on your Mac operating system is as simple as installing any other dedicated Mac program. After you have authorized the SDK on your machine and logged in with your e-mail and password it will be ready for use. From here on out, every time you launch Corona, it will automatically log in to your account. You will notice that you are greeted with a Corona SDK screen when this happens.

Time for action – setting up and activating Corona on Windows

Let's set up Corona SDK on our desktop.

Download Corona SDK from the following URL: http://www.anscamobile.com/corona/. You will have to register as a user before you can access the SDK.
The file extension for the Windows version of Corona should end in .msi, otherwise known as a Windows Installer, a component of Windows made for installing programs by Microsoft. Double-click on the file. The filename should be similar to CoronaSDK.msi.
Follow the onscreen directions for installation.
Corona will install directly to your Programs folder by default. On Microsoft Windows, select Corona from the list of Programs in your Start menu or double-click the Corona icon on the desktop. Upon successful activation, you should begreeted with the following screen:
Note
The process to activate the SDK should be the same as that of the Mac procedure once you launch Corona for the very first time.
Tip
If you run into issues with images not displaying properly, check to see if you're using an up-to-date OpenGL graphics driver that is 1.3 or higher.
Note
Be aware that Corona SDK on Windows can only build for Android devices, not for iOS devices (iPhone, iPad, or iPod Touch). A Mac can only build for iOS devices in Corona but can also build applications for Android.
To create device builds, Java 6 SDK needs to be installed on your PC. You will need to go to the JDK download page: http://jdk6.java.net/download.html and click the Download button under the Java SE 6 option.
On the next page, select the Accept License Agreement radio button and then click on the Windows x86 link to download the installer. You will be asked to log in or create a user account on the Oracle website if you don't already have one.
As soon as the JDK is downloaded, run the installer. Once installed, you'll be able to create device builds for Android on your PC.

What just happened?

Installing the SDK on Windows has a different setup to that of the Mac OS X. While executing the installer file, Windows will automatically present a designated location to install the application such as the Programs folder so you won't have to manually choose a destination. Upon a successful installation you will see the Corona SDK icon on your desktop for easy access or highlighted in the Programs list in the Start menu, assuming you're accessing it for the first time. When you authorize Corona on your machine and sign in with your login information, it is ready for you to use and will lo in automatically every time it is launched.

Using the simulator on Mac and Windows

On Mac OS X, launch Corona SDK by either selecting Corona Terminal or Corona Simulator from the Applications Directory. Both selections will access the SDK. The Corona Simulator will only open the simulator. The Corona Terminal will open both the simulator and terminal window. The terminal is helpful for debugging your programs and displays simulator errors/warnings and print() messages.

On Microsoft Windows, select the Corona SDK folder and click on Corona Simulator from the list of Programs in your Start menu or double-click the Corona icon on the desktop. (The simulator and terminal are always opened together if you are using Windows).

Let's go over the useful contents contained in the Corona SDK folder (located in Applications/Corona SDK on Mac and Start/All Programs/Corona SDK on Windows:

Debugger (Mac)/Corona Debugger (Windows)—Tool for finding and isolating issues in your code.
Corona Simulator—The environment used to launch your application for testing. It simulates the mobile device you're developing on your local computer. (On Windows, it will open both the simulator and terminal).
Corona Terminal—Launches the Corona Simulator and opens a Terminal window to display error/warning messages and print() statements. It is very helpful for debugging your code (only on Mac).
Simulator—Has the same properties as Corona Terminal, but called from the command line (only on Mac).
SampleCode—A set of sample applications to get you started with Corona. Contains code and art assets to work with.

The Corona SDK window opens by default when you launch the simulator. You can open a Corona project in the simulator, create a device build for testing or distribution, and view soe example games and apps to get you familiar with the SDK.

Time for action – viewing a sample project in the simulator

Let's take a look at the HelloPhysics sample project in the simulator:

Click on Simulator in the Corona SDK window.
In the Open dialog that appears, navigate to Applications/CoronaSDK/SampleCode/Physics/HelloPhysics (Mac) or C:\Program Files\Ansca\Corona SDK\Sample Code\Physics\HelloPhysics (Windows). On Mac, click Open and it will automatically open main.lua. On Windows, double-click on main.lua to open the file. The HelloPhysics application opens and runs in the Simulator.

What just happened?

Accessing the SDK through the Corona Terminal or Corona Simulator depends on your preference of action. Many Mac users prefer to use the Corona Terminal so they can track messages outputted in the terminal, especially for debugging purposes. When you launch the SDK through the Corona Simulator, the simulator will display, but not the terminal window. When Windows users launch the Corona Simulator, it will display both the simulator and terminal windows. This is nice to use when you want to play around with any of the example applications that are provided by Corona.

The main.lua file is a special filename that tells Corona where to start in a project folder. This file can also load other code files or other program resources such as sounds or graphics.

When you launch the HelloPhysics application in Corona, you will observe a box object fall from top of the screen in the simulator and collide with a ground object. The transition from launching the main.lua file to viewing the results in the simulator are almost immediate.

Have a go hero – use a different device shell

As you start getting familiar with the Corona Simulator, whether you're in Windows or Mac OSX, a default device is always used when you launch an application. Windows uses the Droid as the default device, while the Mac OS X uses the regular iPhone. Try launching the sample code on a different device shell to view the difference in screen resolution in all the devices the simulator has available.

When porting builds to more than one platform, you'll have to consider the variety of screen resolutions in both iOS and Android devices. A build is a compiled version of all your source code converted into one file. Having your game build configured for multiple platforms broadens the audience reach for your application.

Choosing a text editor

Corona does not have a designated program editor to code in so you will have to find one that suits your needs.

For Mac OS, TextWrangler is a good one and free too! You can download it at http://www.barebones.com/products/textwrangler/download.html. Other text editors such as BBEdit at http://www.barebones.com/thedeck and TextMate at http://macromates.com/ are great, but you will need to purchase those in order to use them. TextMate is also compatible with the Corona TextMate Bundle: http://www.ludicroussoftware.com/corona-textmate-bundle/index.html.

For Microsoft Windows Notepad++ is recommended and can be downloaded at http://notepad-plus-plus.org/ or Crimson Editor at http://www.crimsoneditor.com/. Both editors are free.

Any text editor, such as TextEdit for Mac or Notepad for Windows, that is already included in each operating system works as well, but it'll be easier to work with one that is designed for programming. For Corona, using an editor that supports Lua syntax highlighting will work the best when coding. Syntax highlighting adds formatting attributes to keywords and punctuation in a way that makes it easier for the reader to separate code from text.

Developing on devices

Apple's developer kit Xcode or the Android SDK is not necessary to download if you only want to use the Corona Simulator. In order to build and test your code on an iOS device (iPhone, iPod Touch and iPad), you will need to sign up as an Apple Developer and create and download provisioning profiles. If you want to develop on Android, you don't need to download the Android SDK unless you want to use the ADB tool to help with installing builds and viewing debug messages.

The trial version of Corona Simulator allows building Adhoc (for iOS) and Debug builds (Android) for testing on your own devices. The builds will contain a Trial User message box when the app runs on the device. You will need to purchase a Corona Subscription if you want to build for Apple's App Store or Android's Google Play Store. Corona Subscribers also get the benefit of subscriber-only features such as access to Daily Builds, Subscribers Only areas on the Corona forums and LaunchPad.

Corona SDK Mobile Game Development: Beginner's Guide: You don't need to be a programming whiz to create iOS and Android games. You just need this great hands-on guide to Corona SDK, which teaches you everything from game physics to successful marketing.

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