cocos2d-x 入門——hello world 解析

接下來我們來看，AppDelegate的代碼。

先看申明

class  AppDelegate : private cocos2d::CCApplication
{
public:
    AppDelegate();
    virtual ~AppDelegate();

    /**
    @brief    Implement CCDirector and CCScene init code here.
    @return true    Initialize success, app continue.
    @return false   Initialize failed, app terminate.
    */
    virtual bool applicationDidFinishLaunching();

    /**
    @brief  The function be called when the application enter background
    @param  the pointer of the application
    */
    virtual void applicationDidEnterBackground();

    /**
    @brief  The function be called when the application enter foreground
    @param  the pointer of the application
    */
    virtual void applicationWillEnterForeground();
};
           

裡面都有注釋，主要看函數applicationDidFinishLaunching() 

bool AppDelegate::applicationDidFinishLaunching() {
    // initialize director
    CCDirector* pDirector = CCDirector::sharedDirector();
    CCEGLView* pEGLView = CCEGLView::sharedOpenGLView();

    pDirector->setOpenGLView(pEGLView);
	CCSize frameSize = pEGLView->getFrameSize();

    // Set the design resolution
#if (CC_TARGET_PLATFORM == CC_PLATFORM_WINRT) || (CC_TARGET_PLATFORM == CC_PLATFORM_WP8)
    pEGLView->setDesignResolutionSize(designResolutionSize.width, designResolutionSize.height, kResolutionShowAll);
#else
    pEGLView->setDesignResolutionSize(designResolutionSize.width, designResolutionSize.height, kResolutionNoBorder);
#endif

    
    vector<string> searchPath;

    // In this demo, we select resource according to the frame's height.
    // If the resource size is different from design resolution size, you need to set contentScaleFactor.
    // We use the ratio of resource's height to the height of design resolution,
    // this can make sure that the resource's height could fit for the height of design resolution.

    // if the frame's height is larger than the height of medium resource size, select large resource.
	if (frameSize.height > mediumResource.size.height)
	{
        searchPath.push_back(largeResource.directory);

        pDirector->setContentScaleFactor(MIN(largeResource.size.height/designResolutionSize.height, largeResource.size.width/designResolutionSize.width));
	}
    // if the frame's height is larger than the height of small resource size, select medium resource.
    else if (frameSize.height > smallResource.size.height)
    {
        searchPath.push_back(mediumResource.directory);
        
        pDirector->setContentScaleFactor(MIN(mediumResource.size.height/designResolutionSize.height, mediumResource.size.width/designResolutionSize.width));
    }
    // if the frame's height is smaller than the height of medium resource size, select small resource.
	else
    {
        searchPath.push_back(smallResource.directory);

        pDirector->setContentScaleFactor(MIN(smallResource.size.height/designResolutionSize.height, smallResource.size.width/designResolutionSize.width));
    }


    // set searching path
    CCFileUtils::sharedFileUtils()->setSearchPaths(searchPath);
	
    // turn on display FPS
    pDirector->setDisplayStats(true);

    // set FPS. the default value is 1.0/60 if you don't call this
    pDirector->setAnimationInterval(1.0 / 60);

    // create a scene. it's an autorelease object
    CCScene *pScene = HelloWorld::scene();

    // run
    pDirector->runWithScene(pScene);

    return true;
}
           

pDirector是導演類。

重點看這句

// create a scene. it's an autorelease object

    CCScene *pScene = HelloWorld::scene();

 // run

    pDirector->runWithScene(pScene);

這樣他就運作起一個helloworld的場景。

接下來的邏輯就是hello world的内容了

還是看申明：

class HelloWorld : public cocos2d::CCLayer
{
public:
    // Here's a difference. Method 'init' in cocos2d-x returns bool, instead of returning 'id' in cocos2d-iphone
    virtual bool init();  


    // there's no 'id' in cpp, so we recommend returning the class instance pointer
    static cocos2d::CCScene* scene();
    
    // a selector callback
    void menuCloseCallback(CCObject* pSender);
    
    // implement the "static node()" method manually
    CREATE_FUNC(HelloWorld);
};
           

我們一個一個函數來分析：

CREATE_FUNC(HelloWorld);

這個宏用來申明 HelloWorld的creat函數。

to be continue