Cocos-2dx 3.X引擎生命周期

Cocos-2dx 3.X引擎生命周期

安卓中：

安卓层执行一个 AppActivity.java的Activity->static的so库

public class __PROJECT_PACKAGE_LAST_NAME_UF__ extends Cocos2dxActivity {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }

    static {
        System.loadLibrary("game");
    }
}

执行 onCreate()之前会调用父类的Cocos2dxActivity的onCreate()

protected void onCreate(final Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        CocosPlayClient.init(this, false);

        onLoadNativeLibraries();

        sContext = this;
        this.mHandler = new Cocos2dxHandler(this);//处理安卓的弹窗等
        
        Cocos2dxHelper.init(this);
        
        this.mGLContextAttrs = getGLContextAttrs();//获取OpenGL ES的相关属性
        this.init();

        if (mVideoHelper == null) {
            mVideoHelper = new Cocos2dxVideoHelper(this, mFrameLayout);
        }
        
        if(mWebViewHelper == null){
            mWebViewHelper = new Cocos2dxWebViewHelper(mFrameLayout);
        }
    }

运用JNI技术（java_c++交互协议）调用nativeInit(),实例化一个Director，调用Application的run()

void Java_org_cocos2dx_lib_Cocos2dxRenderer_nativeInit(JNIEnv*  env, jobject thiz, jint w, jint h)
{
    auto director = cocos2d::Director::getInstance();
    auto glview = director->getOpenGLView();
    if (!glview)
    {
        glview = cocos2d::GLViewImpl::create("Android app");
        glview->setFrameSize(w, h);
        director->setOpenGLView(glview);

        cocos2d::Application::getInstance()->run();
    }
    ,,, ,,,, ,,,
}

run()调用Application 子类AppDelegate的applicationDidFinishLaunching()，并开启游戏主循环

int Application::run()
{
    ......

    // Initialize instance and cocos2d.
    if (!applicationDidFinishLaunching())
    {
        return 1;
    }

    auto director = Director::getInstance();
    auto glview = director->getOpenGLView();

    // Retain glview to avoid glview being released in the while loop
    glview->retain();

    ......
    //游戏刷新循环
    while(!glview->windowShouldClose())
    {
        QueryPerformanceCounter(&nNow);
        interval = nNow.QuadPart - nLast.QuadPart;
        if (interval >= _animationInterval.QuadPart)
        {
            nLast.QuadPart = nNow.QuadPart;
            director->mainLoop();
            glview->pollEvents();
        }
        else
        {
            // The precision of timer on Windows is set to highest (1ms) by 'timeBeginPeriod' from above code,
            // but it's still not precise enough. For example, if the precision of timer is 1ms,
            // Sleep(3) may make a sleep of 2ms or 4ms. Therefore, we subtract 1ms here to make Sleep time shorter.
            // If 'waitMS' is equal or less than 1ms, don't sleep and run into next loop to
            // boost CPU to next frame accurately.
            waitMS = (_animationInterval.QuadPart - interval) * 1000LL / freq.QuadPart - 1L;
            if (waitMS > 1L)
                Sleep(waitMS);
        }
    }

    // Director should still do a cleanup if the window was closed manually.
    if (glview->isOpenGLReady())
    {
        director->end();
        director->mainLoop();
        director = nullptr;
    }
    glview->release();
}

win_32中：

main主函数里面实例了一个Appdelegate对象，然后调用父类构造器，在父类构造器里面返回一个application对象指针，
有这个对象指针调用application类里面的run方法，run方法里面调用applicationDidFinishLaunching()，
applicationDidFinishLaunching()里面实现了游戏开始的场景。

游戏结束检测，游戏内部有个场景栈（后进后出原则），当我们调用 director->end()时，没有场景存在时，
执行purgeDirector(),结束游戏

void Director::purgeDirector()
{
    reset();

    CHECK_GL_ERROR_DEBUG();
    
    // OpenGL view
    if (_openGLView)
    {
        _openGLView->end();
        _openGLView = nullptr;
    }

#if CC_TARGET_PLATFORM == CC_PLATFORM_ANDROID
    EngineDataManager::destroy();
#endif
    // delete Director
    release();
}