cocos2d-x的main函数代码很少，把一些复杂的接口封装到AppDelegate类里了，“AppDelegate”从词意可以得出是app的代理类，而一些最早的场景都会在AppDelegate类里实现。我们先看一下main.cpp
int APIENTRY _tWinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPTSTR lpCmdLine, int nCmdShow) { UNREFERENCED_PARAMETER(hPrevInstance); UNREFERENCED_PARAMETER(lpCmdLine); #ifdef USE_WIN32_CONSOLE AllocConsole(); freopen("CONIN$", "r", stdin); freopen("CONOUT$", "w", stdout); freopen("CONOUT$", "w", stderr); #endif // create the application instance AppDelegate app; //实例化一个cocos2d_x程序 CCEGLView* eglView = CCEGLView::sharedOpenGLView(); //创建一个视口 eglView->setFrameSize(600, 320); //设置视口的大小 int ret = CCApplication::sharedApplication()->run(); //运行cocos2d_x的实例 #ifdef USE_WIN32_CONSOLE FreeConsole(); #endif return ret; }
AppDelegate类的实现如下：
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. */ //程序启动时自动进入的函数在这里我们一般初始化场景 virtual bool applicationDidFinishLaunching(); /** @brief The function be called when the application enter background @param the pointer of the application */ //程序进入后台时执行的操作 virtual void applicationDidEnterBackground(); /** @brief The function be called when the application enter foreground @param the pointer of the application */ //程序从后台到前台执行调用的函数 virtual void applicationWillEnterForeground(); };
在主函数里 实例化 AppDelegate 时会自动调用
virtual bool applicationDidFinishLaunching();
（为什么会到用它？以后会深入研究）
函数的实现：
bool AppDelegate::applicationDidFinishLaunching() { // initialize director CCDirector *pDirector = CCDirector::sharedDirector(); pDirector->setOpenGLView(CCEGLView::sharedOpenGLView()); // turn on display FPS //打开帧的显示(右下角的数字) pDirector->setDisplayStats(false); // set FPS. the default value is 1.0/60 if you don't call this //设置FPS pDirector->setAnimationInterval(1.0 / 60); // create a scene. it's an autorelease object //创建helloWorld场景 CCScene *pScene = HelloWorld::scene(); // run //执行场景 pDirector->runWithScene(pScene); return true; }
helloworld的场景类如下：
class HelloWorld : public cocos2d::CCLayer { public: // Here's a difference. Method 'init' in cocos2d-x returns bool, instead of returning 'id' in cocos2d-iphone //但调用create成员函数式会自动执行init函数 virtual bool init(); // there's no 'id' in cpp, so we recommand to return the exactly class pointer //返回helloworld场景 static cocos2d::CCScene* scene(); // a selector callback //关闭场景函数 void menuCloseCallback(CCObject* pSender); // implement the "static node()" method manually CREATE_FUNC(HelloWorld); };
CCScene* HelloWorld::scene() { CCScene * scene = NULL; do { // 'scene' is an autorelease object //创建一个场景 scene = CCScene::create(); //判断场景是否创建成功 CC_BREAK_IF(! scene); // 'layer' is an autorelease object //创建一个helloworld布景，这时会会调用init() HelloWorld *layer = HelloWorld::create(); //判断helloworld布景是否成功 CC_BREAK_IF(! layer); // add layer as a child to scene //添加helloworld布景到场景 scene->addChild(layer); } while (0); // return the scene return scene; } // on "init" you need to initialize your instance bool HelloWorld::init() { bool bRet = false; do { ////////////////////////////////////////////////////////////////////////// // super init first ////////////////////////////////////////////////////////////////////////// CC_BREAK_IF(! CCLayer::init()); ////////////////////////////////////////////////////////////////////////// // add your codes below... ////////////////////////////////////////////////////////////////////////// // 1. Add a menu item with "X" image, which is clicked to quit the program. // Create a "close" menu item with close icon, it's an auto release object. CCMenuItemImage *pCloseItem = CCMenuItemImage::create( "CloseNormal.png", "CloseSelected.png", this, menu_selector(HelloWorld::menuCloseCallback)); CC_BREAK_IF(! pCloseItem); // Place the menu item bottom-right conner. pCloseItem->setPosition(ccp(CCDirector::sharedDirector()->getWinSize().width - 20, 20)); // Create a menu with the "close" menu item, it's an auto release object. CCMenu* pMenu = CCMenu::create(pCloseItem, NULL); pMenu->setPosition(CCPointZero); CC_BREAK_IF(! pMenu); // Add the menu to HelloWorld layer as a child layer. this->addChild(pMenu, 1); // 2. Add a label shows "Hello World". // Create a label and initialize with string "Hello World". CCLabelTTF* pLabel = CCLabelTTF::create("Hello World", "Arial", 24); CCLabelTTF* pLabel2 = CCLabelTTF::create("My name is CharlesXue","Arial",20); CC_BREAK_IF(! pLabel2); CC_BREAK_IF(! pLabel); // Get window size and place the label upper. CCSize size = CCDirector::sharedDirector()->getWinSize(); pLabel->setPosition(ccp(size.width / 2, size.height - 50)); pLabel2->setPosition(ccp(size.width / 2,size.height - 70)); // Add the label to HelloWorld layer as a child layer. this->addChild(pLabel, 1); this->addChild(pLabel2,1); // 3. Add add a splash screen, show the cocos2d splash image. CCSprite* pSprite = CCSprite::create("HelloWorld.png"); CC_BREAK_IF(! pSprite); // Place the sprite on the center of the screen pSprite->setPosition(ccp(size.width/2, size.height/2)); // Add the sprite to HelloWorld layer as a child layer. this->addChild(pSprite, 0); bRet = true; } while (0); return bRet; } void HelloWorld::menuCloseCallback(CCObject* pSender) { // "close" menu item clicked CCDirector::sharedDirector()->end(); }