参考了沈大海的博客：
为什么要定义windows平台
因为在不同平台有不同的程序入口实现方式,如windos平台有main.h和main.cpp,android平台有入口的Activity,iso平台有main.m,
但对于各平台的入口差异在cocos2d-x中做了完美的一致化处理，暂且不管是如何进行的，我们只需要基于一致的引擎入口进行开发就好了，
对于cocos2d-x引擎的入口我们定义为AppDelegate.h和AppDelegate.cpp看这里面的方法有三个。
如下图：windows下工程的入口和引擎入口：
这几个方法会在各平台应用程序状态改变时候自动回调。
而状态的改变在不同平台是有差异的，cocos2d-x定义cocos2d::CCApplication类统一了各平台的差异，在cocos2d-x中只有1个窗口在运行（符合移动平台，但pc平台原本不是这样），窗口在分配空间，加载完成，被覆盖，被恢复时候会自动回调CCApplication中的函数，因此CCApplication在不同的平台，有不同的实现cpp,
(有兴趣同学可以阅读cocos2ds/platform下面的源代码，从cocos2d::CCApplication.h开始)
看注释就已经很明白了：
和android的每个activity的活动周期差不多
#ifndef _APP_DELEGATE_H_
#define _APP_DELEGATE_H_
#include "cocos2d.h"
/**
@brief The cocos2d Application.
The reason for implement as private inheritance is to hide some interface call by CCDirector.
*/
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();
};
#endif // _APP_DELEGATE_H_
----------------------------------------------------------------------------------------------------------------------------------
在这几个方法中，就可以做我们要做的事情了。
applicationDidFinishLaunching启动完成
加载游戏，播放音乐
applicationDidEnterBackground进入背景
音乐暂停，游戏暂停
applicationWillEnterForeground恢复窗口
音乐继续，游戏继续
可能，你会想，如果应用退出，我想保留游戏数据如何？
试者找找ccApplication中还有哪些方法。
bool AppDelegate::applicationDidFinishLaunching() {
// initialize director 初始化导演，他是引擎的老大,单例模式
CCDirector* pDirector = CCDirector::sharedDirector();
CCEGLView* pEGLView = CCEGLView::sharedOpenGLView();
//绑定opengles窗口，可见，我们可以自定义openGLView
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
//设置FPS 在cocos2d-x 启动后内部封装了FPS的逻辑，虽然helloWorld图片没变化，但其实一直在重绘。
pDirector->setAnimationInterval(1.0 / 60);
// create a scene. it's an autorelease object 创建一个场景
CCScene *pScene = HelloWorld::scene();
// run 显示这个场景到窗口，必然所有的绘制在场景中定义的
pDirector->runWithScene(pScene);
return true;
}
void HelloWorld::menuCloseCallback(CCObject* pSender)
{
CCLog("click the menu");
#if (CC_TARGET_PLATFORM == CC_PLATFORM_WINRT) || (CC_TARGET_PLATFORM == CC_PLATFORM_WP8)
CCMessageBox("You pressed the close button. Windows Store Apps do not implement a close button.","Alert");
#else
CCDirector::sharedDirector()->end();
#if (CC_TARGET_PLATFORM == CC_PLATFORM_IOS)
exit(0);
#endif
#endif
}
总结：
1 Director启动一个scene。
2 addChild
3 回调函数
4 CCLog