Cocos2d-x Cookbook

5 (3 reviews total)
By Akihiro Matsuura
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    Getting Started with Cocos2d-x
About this book

Cocos2d-x is a suite of open source, cross-platform game-development tools used by thousands of developers all over the world. Cocos2d-x is a game framework written in C++, with a thin platform-dependent layer. Completely written in C++, the core engine has the smallest footprint and the fastest speed of any other game engine, and is optimized to be run on all kinds of devices.

You will begin with the initial setup and installation of Cocos2d before moving on to the fundamentals needed to create a new project. You will then explore and create the sprites, animations, and actions that you will include in the game. Next you will look at strings and create labels, including a label with True Type Font (TTF) font support.

Later, you will learn about layer and scene creation and transition. Then you will create the GUI parts essential for a game, such as buttons and switches. After that, you will breathe life into the game with background music and sound effects using the all new Cocos2d-x audio engine. You will then discover how to manage resource files and implement processes that depend on the operating system.

Finally, you will polish your game with physics such as gravity and elevation, learn about tools that will help you make games more robust and stable, and get to know best practices to improve the game you have developed.

Publication date:
November 2015
Publisher
Packt
Pages
254
ISBN
9781783284757

 

Chapter 1. Getting Started with Cocos2d-x

In this chapter, we're going to install Cocos2d-x and set up the development environment. The following topics will be covered in this chapter:

  • Setting up our Android environment

  • Installing Cocos2d-x

  • Using the Cocos command

  • Building the project using Xcode

  • Building the project using Eclipse

  • Implementing multi-resolution support

  • Preparing your original game

 

Introduction


Cocos2d-x is an open source, cross-platform game engine, which is free and mature. It can publish games for mobile devices and desktops, including iPhone, iPad, Android, Kindle, Windows, and Mac. Cocos2d-x is written in C++, so it can build on any platform. Cocos2d-x is open source written in C++, so we can feel free to read the game framework. Cocos2d-x is not a black box, and this proves to be a big advantage for us when we use it. Cocos2d-x version 3, which supports C++11, was only recently released. It also supports 3D and has an improved rendering performance. This book focuses on using version 3.4, which is the latest version of Cocos2d-x that was available at the time of writing this book. This book also focuses on iOS and Android development, and we'll be using Mac because we need it to develop iOS applications. This chapter explains how to set up Cocos2d-x.

 

Setting up our Android Environment


Getting ready

We begin by setting up our Android environment. If you wish to build only on iOS, you can skip this step. To follow this recipe, you will need some files.

The following list provides the prerequisites that need to be downloaded to set up Android:

  • Eclipse ADT (Android Developer Tools) with the Android SDK:

    https://dl.google.com/android/adt/adt-bundle-mac-x86_64-20140702.zip

    Eclipse ADT includes the Android SDK and Eclipse IDE. This is the Android development tool that is used to develop Android applications. Android Studio is an Android development IDE, but it is not supported to build NDK. The official site states that a version of Android Studio that supports NDK will be released soon. That's why we use Eclipse in this book.

  • Android NDK (Native Development Kit):

    https://dl.google.com/android/ndk/android-ndk-r10c-darwin-x86_64.bin

    The NDK is required to build an Android application. You have to use NDK r10c. This is because compiling and linking errors may occur when using NDK r9 or an earlier version.

  • Apache ANT:

    You can download Apache ANT from http://ant.apache.org/bindownload.cgi

    This is a java library that aids in building software. At the time of writing this book, version 1.9.4 was the latest stable version available.

How to do it...

  1. You begin by installing Eclipse ADT with the Android SDK, and then continue to unzip the zip file to any working directory you are aware of. I recommend that you unzip it to the Documents folder (~/adt-bundle-mac-x86_64-20140702). ADT includes Android SDK and Eclipse. The SDK and Eclipse folders are located under the ADT folder. We call the SDK folder path that is located under the ADT folder ANDROID_SDK_ROOT. You have to remember it because you will use it the next recipe. Now, you can launch Eclipse from ~/adt-bundle-mac-x86_64-20140702/eclipse/Eclipse.app.

  2. The next step is to update Android SDK:

    • Open Eclipse from the eclipse folder located in ADT.

    • Go to Window | Android SDK Manager.

    • After opening Android SDK Manager, check Tools and the latest Android SDK (API21), Android 2.3.3(API10), and any other SDK if necessary, as shown in the following screenshot:

    • Click on Install packages....

    • Select each license and click on Accept, as shown in the following screenshot:

    • After you accept all licenses, you will see that the Install button is enabled. Click on it.

    • You have to wait for a long time to update and install the SDKs.

  3. Installing NDK:

    Open the terminal window and change the directory to the path from which you downloaded the package. Change the permission on the downloaded package and execute the package. For example:

    $ chmod 700 android-ndk-r10c-darwin-x86_64.bin
    $ ./android-ndk-r10c-darwin-x86_64.bin
    

    Finally, you move the NDK folder to the Documents folder. We call the installation path for NDK NDK_ROOT. NDK_ROOT is the address of the folder that contains the files, it helps the Cocos2dx engine to locate the native files of Android. You have to remember NDK_ROOT because you will use it in the next recipe.

  4. Installing Apache ANT:

    Unzip the file to the Documents folder. That's all. We call ANT_ROOT the installation path for ANT. You have to remember ANT_ROOT, as we'll be using it in the next recipe.

  5. Installing Java:

    By entering the following command in the terminal, you can automatically install Java (if you haven't installed it earlier):

    $ java --version
    

    After installing it, you can check that it was successfully installed by entering the command again.

How it works...

Let's take a look at what we did throughout the recipe:

  • Installing Eclipse: You can use Eclipse as an editor for Cocos2d-x

  • Installing ADT: You can develop Android applications on Eclipse

  • Installing NDK: You can build a C++ source code for Java

  • Installing ANT: You can use command line tools for Cocos2d-x

Now you've finished setting up the Android development environment. At this point, you know how to install them and their path. In the next recipe, you will use them to build and execute Android applications. This will be very useful when you want to debug Android applications.

 

Installing Cocos2d-x


Getting ready

To follow this recipe, you need to download the zip file from the official site of Cocos2d-x (http://www.cocos2d-x.org/download).

At the time of writing this book, version 3.4 was the latest stable version that was available. This version will be used throughout this book.

How to do it...

  1. Unzip your file to any folder. This time, we will install the user's home directory. For example, if the user name is syuhari, then the install path is /Users/syuhari/cocos2d-x-3.4. In this book, we call it COCOS_ROOT.

  2. The following steps will guide you through the process of setting up Cocos2d-x:

    • Open the terminal

    • Change the directory in terminal to COCOS_ROOT, using the following command:

      $ cd ~/cocos2d-x-v3.4
      
    • Run setup.py, using the following command:

      $ ./setup.py
      
    • The terminal will ask you for NDK_ROOT. Enter into NDK_ROOT path.

    • The terminal will then ask you for ANDROID_SDK_ROOT. Enter the ANDROID_SDK_ROOT path.

    • Finally, the terminal will ask you for ANT_ROOT. Enter the ANT_ROOT path.

    • After the execution of the setup.py command, you need to execute the following command to add the system variables:

      $ source ~/.bash_profile
      

      Tip

      Open the .bash_profile file, and you will find that setup.py shows how to set each path in your system. You can view the .bash_profile file using the cat command:

      $ cat ~/.bash_profile
      
  3. We now verify whether Cocos2d-x can be installed:

    • Open the terminal and run the cocos command without parameters:

      $ cocos
      
    • If you can see a window like the following screenshot, you have successfully completed the Cocos2d-x install process:

How it works...

Let's take a look at what we did throughout the above recipe. You can install Cocos2d-x by just unzipping it. You know setup.py is only setting up the cocos command and the path for Android build in the environment. Installing Cocos2d-x is very easy and simple. If you want to install a different version of Cocos2d-x, you can do that too. To do so, you need to follow the same steps that are given in this recipe, but they will be for a different version.

There's more...

Setting up the Android environment is a bit tough. If you recently started to develop Cocos2d-x, you can skip the settings part of Android. and you can do it when you run on Android. In this case, you don't have to install Android SDK, NDK, and Apache ANT. Also, when you run setup.py, you only press Enter without entering a path for each question.

 

Using the Cocos command


The next step is using the cocos command. It is a cross-platform tool with which you can create a new project, build it, run it, and deploy it. The cocos command works for all Cocos2d-x supported platforms and you don't need to use an IDE if you don't want to. In this recipe, we take a look at this command and explain how to use it.

How to do it...

  1. You can use the cocos command help by executing it with the --help parameter, as follows:

    $ cocos --help
    
  2. We then move on to generating our new project:

    First, we create a new Cocos2d-x project with the cocos new command, as shown here:

    $ cocos new MyGame -p com.example.mygame -l cpp -d ~/Documents/
    

    The result of this command is shown the following screenshot:

    Behind the new parameter is the project name. The other parameters that are mentioned denote the following:

    • MyGame is the name of your project.

    • -p is the package name for Android. This is the application ID in the Google Play store. So, you should use the reverse domain name as the unique name.

    • -l is the programming language used for the project. You should use cpp because we will use C++ in this book.

    • -d is the location in which to generate the new project. This time, we generate it in the user's documents directory.

    You can look up these variables using the following command:

    $ cocos new —help
    

    Congratulations, you can generate your new project. The next step is to build and run using the cocos command.

  3. Compiling the project:

    If you want to build and run for iOS, you need to execute the following command:

    $ cocos run -s ~/Documents/MyGame -p ios
    

    The parameters that are mentioned are explained as follows:

    • -s is the directory of the project. This could be an absolute path or a relative path.

    • -p denotes which platform to run on. If you want to run on Android you use -p android. The available options are IOS, Android, Win32, Mac, and Linux.

    • You can run cocos run –help for more detailed information.

    The result of this command is shown in the following screenshot:

  4. You can now build and run iOS applications on cocos2d-x. However, you have to wait for a long time if this is your first time building an iOS application. It takes a long time to build a Cocos2d-x library, depending on if it was a clean build or a first build.

How it works...

The cocos command can create a new project and build it. You should use the cocos command if you want to create a new project. Of course, you can build using Xcode or Eclipse. You can easily develop and debug using these tools.

There's more...

The cocos run command has other parameters. They are the following:

  • --portrait will set the project as a portrait. This command has no argument.

  • --ios-bundleid will set the bundle ID for the iOS project. However, it is not difficult to set it later.

The cocos command also includes some other commands, which are as follows:

  • The compile command: This command is used to build a project. The following patterns are useful parameters. You can see all parameters and options if you execute the cocos compile [–h] command:

    cocos compile [-h] [-s SRC_DIR] [-q] [-p PLATFORM] [-m MODE]
    
  • The deploy command: This command only takes effect when the target platform is Android. It will re-install the specified project to the android device or simulator:

    cocos deploy [-h] [-s SRC_DIR] [-q] [-p PLATFORM] [-m MODE]
    

    Tip

    The run command continues to compile and deploy commands.

 

Building the project using Xcode


Getting ready

Before building the project using Xcode, you require Xcode with an iOS developer account to test it on a physical device. However, you can also test it on an iOS simulator. If you did not install Xcode, you can get it from the Mac App Store. Once you have installed it, get it activated.

How to do it...

  1. Open your project from Xcode:

    You can open your project by double-clicking on the file placed at: ~/Documents/MyGame/proj.ios_mac/MyGame.xcodeproj:

  2. Build and Run using Xcode:

    You should select an iOS simulator or real device on which you want to run your project.

How it works...

If this is your first time building, it will take a long time but continue to build with confidence as it's the first time. You can develop your game faster if you develop and debug it using Xcode rather than Eclipse.

 

Building the project using Eclipse


Getting ready

You must finish the first recipe before you begin this step. If you have not finished it yet, you will need to install Eclipse.

How to do it...

  1. Setting up NDK_ROOT:

    • Open the preference of Eclipse

    • Open C++ | Build | Environment

  2. Click on Add and set the new variable, the name is NDK_ROOT, and the value is NDK_ROOT path:

  3. Importing your project into Eclipse:

    • Open the file and click on Import

    • Go to Android | Existing Android Code into Workspace

    • Click on Next

  4. Import the project into Eclipse at ~/Documents/MyGame/proj.android:

  5. Importing the Cocos2d-x library into Eclipse:

    • Perform the same steps from Step 3 to Step 4.

    • Import the project cocos2d lib at ~/Documents/MyGame/cocos2d/cocos/platform/android/java, using the following command:

      importing cocos2d lib
      
  6. Build and Run:

    • Click on the Run icon

    • The first time, Eclipse will ask you to select a way to run your application. Select Android Application and click on OK, as shown in the following screenshot:

    • If you connected to the Android device on your Mac, you can run your game on your real device or an emulator. The following screenshot shows that it is running on Nexus5:

  7. If you added cpp files into your project, you have to modify the Android.mk file at ~/Documents/MyGame/proj.android/jni/Android.mk. This file is needed to build the NDK. This fix is required to add files.

  8. The original Android.mk would look as follows:

    LOCAL_SRC_FILES := hellocpp/main.cpp \
                       ../../Classes/AppDelegate.cpp \
                       ../../Classes/HelloWorldScene.cpp
  9. If you added the TitleScene.cpp file, you have to modify it as shown in the following code:

    LOCAL_SRC_FILES := hellocpp/main.cpp \
                       ../../Classes/AppDelegate.cpp \
                       ../../Classes/HelloWorldScene.cpp \
                       ../../Classes/TitleScene.cpp 

The preceding example shows an instance of when you add the TitleScene.cpp file. However, if you are also adding other files, you need to add all the added files.

How it works...

You get lots of errors when importing your project into Eclipse, but don't panic. After importing the Cocos2d-x library, errors soon disappear. This allows us to set the path of the NDK, Eclipse could compile C++. After you have modified the C++ codes, run your project in Eclipse. Eclipse automatically compiles C++ codes, Java codes, and then runs.

It is a tedious task to fix Android.mk again to add the C++ files. The following code is the original Android.mk:

LOCAL_SRC_FILES := hellocpp/main.cpp \
                   ../../Classes/AppDelegate.cpp \
                   ../../Classes/HelloWorldScene.cpp

LOCAL_C_INCLUDES := $(LOCAL_PATH)/../../Classes

The following code is the customized Android.mk that adds C++ files automatically:

CPP_FILES := $(shell find $(LOCAL_PATH)/../../Classes -name *.cpp)
LOCAL_SRC_FILES := hellocpp/main.cpp
LOCAL_SRC_FILES += $(CPP_FILES:$(LOCAL_PATH)/%=%)

LOCAL_C_INCLUDES := $(shell find $(LOCAL_PATH)/../../Classes -type d)

The first line of the code gets C++ files to the Classes directory into the CPP_FILES variable. The second and third lines add C++ files into the LOCAL_C_INCLUDES variable. By doing so, C++ files will be automatically compiled in the NDK. If you need to compile a file other than the extension .cpp file, you will need to add it manually.

There's more...

If you want to manually build C++ in NDK, you can use the following command:

$ ./build_native.py

This script is located in ~/Documents/MyGame/proj.android . It uses ANDROID_SDK_ROOT and NDK_ROOT in it. If you want to see its options, run ./build_native.py –help.

 

Implementing multi-resolution support


You may notice a difference in screen appearance on different devices. In some previous recipes, there is an iOS's screenshot and a Nexus 5's screenshot. It shows different image sizes. This image is HelloWorld.png located at MyGame/Resources. It is 480 x 320 pixels. In this recipe, we explain how to maintain the same size regardless of screen size.

How to do it…

Open AppDelegate.cpp through Xcode, and modify the AppDelegate::applicationDidFinishLaunching() method by adding the code after the director->setAnimationInterval(1.0/60.0); line, as shown in the following code:

director->setAnimationInterval(1.0 / 60);
glview->setDesignResolutionSize(640, 960, ResolutionPolicy::NO_BORDER);

In this book, we design the game with a screen size of iPhone's 3.5 inch screen. So, we set this screen size to the design resolution size by using the setDesignResolutionSize method. The last parameter is resolution policy. The following screenshot is the Nexus 5's screenshot after implementing multi-resolution:

The following screenshot is the iPhone 5 simulator's screenshot. You now know that both screenshots have the same appearance:

How it works…

The resolution policy has EXACT_FIT, NO_BORDER, SHOW_ALL, FIXED_HEIGHT, and FIXED_WIDTH. These are explained as follows:

  • EXACT_FIT: The entire application is visible in the specified area without trying to preserve the original aspect ratio.

  • NO_BORDER: The entire application fills the specified area, without distortion but possibly with some cropping, while maintaining the original aspect ratio of the application.

  • SHOW_ALL: The entire application is visible in the specified area without distortion, while maintaining the internal the aspect ratio of the application. Borders can appear on two sides of the application.

  • FIXED_HEIGHT: The application takes the height of the design resolution size and modifies the width of the internal canvas so that it fits the aspect ratio of the device. No distortion will occur, however, you must make sure your application works on different aspect ratios.

  • FIXED_WIDTH: The application takes the width of the design resolution size and modifies the height of the internal canvas so that it fits the aspect ratio of the device. No distortion will occur, however, you must make sure your application works on different aspect ratios.

By implementing multi-resolution, regardless of screen size, you will maintain the image on the screen.

 

Preparing your original game


In the next chapter, we will start the original game. You know there are a lot of comments and codes in HelloWorldScene.cpp and the HelloWorldScene.h file. That's why we will remove unnecessary codes in the template project and get started with the original game right away.

How to do it…

  1. Open HelloWorldScene.h and remove the menuCloseCallback method and unnecessary comments. Now HelloWorldScene.h should look like the following code:

     #ifndef __HELLOWORLD_SCENE_H__
       #define __HELLOWORLD_SCENE_H__
       #include "cocos2d.h" 
    
       class HelloWorld : public cocos2d::Layer
       { 
    public:
        static cocos2d::Scene* createScene();
        virtual bool init();
        CREATE_FUNC(HelloWorld);
    };
    #endif // __HELLOWORLD_SCENE_H__
  2. The next step is to open HelloWorldScene.cpp and remove unnecessary comments, codes, and methods. Now HelloWorldScene.cpp should look like the following code:

    #include "HelloWorldScene.h"
    USING_NS_CC; 
    Scene* HelloWorld::createScene()
    {
        auto scene = Scene::create();
        auto layer = HelloWorld::create();
        scene->addChild(layer);
        return scene;
    } 
    bool HelloWorld::init()
    {
        if ( !Layer::init() )
        {
            return false;
        }
        return true;
    }
  3. The next step is to remove unnecessary images in resources. Remove CloseNormal.png, CloseSelected.png and HelloWorld.png from the Resources folder in Xcode:

  4. Finally, if you are developing only iOS and Android applications, you don't need files for other platforms such as Linux, Windows, and Windows Phone. You should remove these files.

    Before removing platform files, it should look like the following screenshot:

    After removing platform files, it should look like the following screenshot:

How it works…

With this recipe, you can get the simplest project ready before removing unnecessary comments, codes, and methods. Removing unnecessary platform codes and resources is important for reducing the size of your application. If you start building your original game from scratch, you will need to follow this recipe or chances are, you may get a black screen if you build and run this project. In the next chapter, you can start coding within this simple project.

About the Author
  • Akihiro Matsuura

    Akihiro Matsuura has five years of experience as a Cocos2d-x developer. He founded his own company called Syuhari, Inc. five years ago. He has more than 20 years of experience as a programmer. He has written three technical books in Japanese. He also authored Cocos2d-x Recipe Book, Shuwa System Co., Ltd , the first Cocos2d-x book in Japan, iPhone SDK Recipe Book , Shuwa System Co., Ltd, and Cocos2d-x Guide Book, Mynavi Corporation.

    7 years ago, iPhone3G was released in Japan. This was when he began to develop its software and ended up developing a lot of applications for iPhone. First, he developed them using Cocos2d for iPhone; however, he had to port to Android. So, he decided to use Cocos2d-x to develop cross-platform applications. At that time, Cocos2d-x was at version 1.0.

    Since then, he has developed a lot of applications using Cocos2d-x.

    Browse publications by this author
Latest Reviews (3 reviews total)
a little out of date. could be better presented.
Very good book which explains many important topics and provides code examples for everything.
Great book. Excellent examples that are actually fun to work through. And does not have extra crud getting in the way of the concept being taught.
Cocos2d-x Cookbook
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