LNK2019在功能中未解决的外部符号引用

在visual studio中运行的基本cocos2dx应用程序中出现链接器错误。当AppDelegate的"applicationDidFinishLaunching"方法调用"MyGameScene"的"singleton"方法时发生。我已经检查了MyGameScene.h中定义的方法在MyGameScene.cpp类

错误味精

Error   1   error LNK2019: unresolved external symbol "public: static class
MyGame * __cdecl MyGame::singleton(void)" (?singleton@MyGame@@SAPAV1@XZ) 
referenced in function "public: virtual bool __thiscall 
AppDelegate::applicationDidFinishLaunching(void)" 
(?applicationDidFinishLaunching@AppDelegate@@UAE_NXZ)   D:Devcocos2d-2.0-x-
2.0.4MyGameproj.win32AppDelegate.obj MyGame

AppDelegate.h

#ifndef  _APP_DELEGATE_H_
#define  _APP_DELEGATE_H_
#include "CCApplication.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_

AppDelegate.cpp

#include "AppDelegate.h"
#include "cocos2d.h"
#include "MyGameScene.h"
USING_NS_CC;
AppDelegate::AppDelegate()
{
}
AppDelegate::~AppDelegate()
{
}
bool AppDelegate::applicationDidFinishLaunching()
{
// initialize director
CCDirector *pDirector = CCDirector::sharedDirector();
pDirector->setOpenGLView(CCEGLView::sharedOpenGLView());
// 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
MyGame *MyGame = MyGame::singleton();
CCScene *pScene = MyGame->scene();
// run
pDirector->runWithScene(pScene);
return true;
}
// This function will be called when the app is inactive. When comes a phone call,it's be invoked too
void AppDelegate::applicationDidEnterBackground()
{
CCDirector::sharedDirector()->pause();
// if you use SimpleAudioEngine, it must be pause
// SimpleAudioEngine::sharedEngine()->pauseBackgroundMusic();
}
// this function will be called when the app is active again
void AppDelegate::applicationWillEnterForeground()
{
CCDirector::sharedDirector()->resume();
// if you use SimpleAudioEngine, it must resume here
// SimpleAudioEngine::sharedEngine()->resumeBackgroundMusic();
}

MyGameScene.h

#ifndef __MYGAME_SCENE_H__
#define __MYGAME_SCENE_H__
#include "cocos2d.h"
#include "Box2D/Box2d.h"
#define PTM_RATIO 32
USING_NS_CC;
class MyGame: public cocos2d::CCLayer {
public:
    cocos2d::CCSprite *_ball;
    // implement the "static node()" method manually
    CREATE_FUNC(MyGame)
    ;
    static MyGame *singleton();
    MyGame();
    ~MyGame();
    // 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 recommand to return the exactly class pointer
    cocos2d::CCScene* scene();
    // a selector callback
    void menuCloseCallback(CCObject* pSender);
    void Tick(float dt);
private:
    CCScene *_scene;
    int mWidth;
    int mHeight;
};
#endif // __MYGAME_SCENE_H__

MyGameScene.cpp

    #include "MyGameScene.h"
//#include "SimpleAudioEngine.h"
#include "Shaders.h"
using namespace cocos2d;
//using namespace CocosDenshion;
#define COCOS2D_DEBUG 1
extern "C" {
#include <pthread.h>
#include <unistd.h>
}
static MyGame *_MyGameSingleton = NULL;
static bool mIsNewFrameReceived;
MyGame* MyGame::singleton() {
    // 'layer' is an autorelease object
    if (_MyGameSingleton == NULL) {
        _MyGameSingleton = MyGame::create();
    }
    return _MyGameSingleton;
}
CCScene* MyGame::scene() {
    if (!_scene) {
        // 'scene' is an autorelease object
        _scene = CCScene::create();
        // add layer as a child to scene
        _scene->addChild(this);
    }
    // return the scene
    return _scene;
}
// on "init" you need to initialize your instance
bool MyGame::init() {
    _scene = NULL;
    if (!CCLayer::init()) {
        return false;
    }
//  CCLOG("init");
//  CCSize winSize = CCDirector::sharedDirector()->getWinSize();
//  mWidth = winSize.width;
//  mHeight = winSize.height;
    this->schedule(schedule_selector(MyGame::Tick));
    return true;
}
void MyGame::menuCloseCallback(CCObject* pSender) {
    CCDirector::sharedDirector()->end();
#if (CC_TARGET_PLATFORM == CC_PLATFORM_IOS)
    exit(0);
#endif
}
MyGame::~MyGame() {
}

MyGame::MyGame() {
}
void MyGame::Tick(float dt) {
    CCDirector *director = CCDirector::sharedDirector();
    CCSize windowSize = director->getVisibleSize();
    mWidth = windowSize.width;
    mHeight = windowSize.height;
}

我在Visual Studio本身的项目中创建了一个新类，并将MyGame类的所有变量和成员函数复制到其中。然后，我就可以引用新类并正确编译了。

[复制我的评论供参考]我能够使用cygwin在windows上编译现有的cocos2dx游戏，我的同事能够使用XCode在Mac上编译相同的东西。问题只在用Visual Studio

我认为Visual Studio没有编译MyGame文件。我如何确保类将被编译?