cocos2d-x C++ 原始工程引擎运行机制解析

 1 #ifndef  _APP_DELEGATE_H_
 2 #define  _APP_DELEGATE_H_
 3 
 4 #include "cocos2d.h"
 5 
 6 /**
 7 @brief    The cocos2d Application.
 8 
 9 Private inheritance here hides part of interface from Director.
10 */  //从这里可以看到AppDelegate继承了cocos2d::Application ，而cocos2d::Application是cocos2d-x引擎提供的基类
11 class  AppDelegate : private cocos2d::Application
12 {
13 public:
14     AppDelegate();
15     virtual ~AppDelegate();
16     /*
17      
18      */
19     virtual void initGLContextAttrs();
20 
21     /**
22     @brief    Implement Director and Scene init code here.
23     @return true    Initialize success, app continue.
24     @return false   Initialize failed, app terminate.
25         *游戏启动时调用的函数，在这里可以初始化导演对象和场景对象
26     */
27     virtual bool applicationDidFinishLaunching();
28 
29     /**
30     @brief  Called when the application moves to the background
31     @param  the pointer of the application
32         *游戏进入后台时调用的函数
33     */
34     virtual void applicationDidEnterBackground();
35 
36     /**
37     @brief  Called when the application reenters the foreground
38     @param  the pointer of the application
39         *游戏进入前台时调用的函数
40     */
41     virtual void applicationWillEnterForeground();
42 };
43 
44 #endif // _APP_DELEGATE_H_

#include "AppDelegate.h"
#include "HelloWorldScene.h"

USING_NS_CC;//这个是cocos2d－x提供的一个宏，它是用来替换 using namespace cocos2d语句的。

static cocos2d::Size designResolutionSize = cocos2d::Size(480, 320);
static cocos2d::Size smallResolutionSize = cocos2d::Size(480, 320);
static cocos2d::Size mediumResolutionSize = cocos2d::Size(1024, 768);
static cocos2d::Size largeResolutionSize = cocos2d::Size(2048, 1536);

AppDelegate::AppDelegate()
{
}

AppDelegate::~AppDelegate() 
{
}

// if you want a different context, modify the value of glContextAttrs
// it will affect all platforms
void AppDelegate::initGLContextAttrs()
{
    // set OpenGL context attributes: red,green,blue,alpha,depth,stencil
    GLContextAttrs glContextAttrs = {8, 8, 8, 8, 24, 8};

    GLView::setGLContextAttrs(glContextAttrs);
}

// if you want to use the package manager to install more packages,  
// don‘t modify or remove this function
static int register_all_packages()
{
    return 0; //flag for packages manager
}

// 游戏启动时调用的函数
bool AppDelegate::applicationDidFinishLaunching() {
    // initialize director
    auto director = Director::getInstance();//初始化导演类
    auto glview = director->getOpenGLView();
    if(!glview) {
#if (CC_TARGET_PLATFORM == CC_PLATFORM_WIN32) || (CC_TARGET_PLATFORM == CC_PLATFORM_MAC) || (CC_TARGET_PLATFORM == CC_PLATFORM_LINUX)
        glview = GLViewImpl::createWithRect("NotesDamo", cocos2d::Rect(0, 0, designResolutionSize.width, designResolutionSize.height));
#else
        glview = GLViewImpl::create("NotesDamo");
#endif
        director->setOpenGLView(glview);//设置导演类的OpenGL视图
    }

    // turn on display FPS
    director->setDisplayStats(true);//设置是否在屏幕上显示帧率信息(一般都是为了测试，实际发布时是不会显示的)

    // set FPS. the default value is 1.0/60 if you don‘t call this
    director->setAnimationInterval(1.0f / 60);//一秒执行60帧

    // Set the design resolution
    glview->setDesignResolutionSize(designResolutionSize.width, designResolutionSize.height, ResolutionPolicy::NO_BORDER);
    auto frameSize = glview->getFrameSize();
    // if the frame‘s height is larger than the height of medium size.
    if (frameSize.height > mediumResolutionSize.height)
    {        
        director->setContentScaleFactor(MIN(largeResolutionSize.height/designResolutionSize.height, largeResolutionSize.width/designResolutionSize.width));
    }
    // if the frame‘s height is larger than the height of small size.
    else if (frameSize.height > smallResolutionSize.height)
    {        
        director->setContentScaleFactor(MIN(mediumResolutionSize.height/designResolutionSize.height, mediumResolutionSize.width/designResolutionSize.width));
    }
    // if the frame‘s height is smaller than the height of medium size.
    else
    {        
        director->setContentScaleFactor(MIN(smallResolutionSize.height/designResolutionSize.height, smallResolutionSize.width/designResolutionSize.width));
    }

    register_all_packages();

    // create a scene. it‘s an autorelease object
    auto scene = HelloWorld::createScene();//创建导演类对象scene

    // run
    director->runWithScene(scene);//运行该场景(会使游戏进入该场景)

    return true;
}

// This function will be called when the app is inactive. Note, when receiving a phone call it is invoked.

//游戏进入后台时调用的函数
void AppDelegate::applicationDidEnterBackground() {
    Director::getInstance()->stopAnimation();//停止场景中的动画

    // if you use SimpleAudioEngine, it must be paused
    // 停止背景音乐，默认时注释掉的
    // SimpleAudioEngine::getInstance()->pauseBackgroundMusic();
}

// this function will be called when the app is active again
// 游戏进入前台时调用的函数
void AppDelegate::applicationWillEnterForeground() {
    Director::getInstance()->startAnimation();//开始场景中的动画

    // if you use SimpleAudioEngine, it must resume here
    // 继续背景音乐的，默认是注释掉的
    // SimpleAudioEngine::getInstance()->resumeBackgroundMusic();
}

 1 #ifndef __HELLOWORLD_SCENE_H__
 2 #define __HELLOWORLD_SCENE_H__
 3 
 4 #include "cocos2d.h"
 5 
 6 
 7 /*
 8  *在这里我们可以看出，HelloWorld类继承了cocos2d::Layer类；它被称为层(layer)，这些层被放到了场景(scene)中，场景类是：cocos2d::Scene；
 9     注意：HelloWorld.h虽然命名为场景，但是它内部定义的HelloWorld类是一个层
10  */
11 //HelloWorld继承了cocos2d::Layer，HelloWorld是一个层，而不是场景。
12 class HelloWorld : public cocos2d::Layer
13 {
14     
15 public:
16     
17     static cocos2d::Menu* m_pSelectedItem();
18     
19     virtual ~HelloWorld(){}
20     
21     static cocos2d::Scene* createScene();//声明创建当前的层HelloWorld所在场景的静态函数createScene()；
22     
23     virtual bool init();//声明初始化层HelloWorld实例函数。
24     
25     // a selector callback
26     void menuCloseCallback(cocos2d::Ref* pSender);//声明菜单回调函数menuCloseCallback，用于触摸菜单事件的回调。
27     
28     CREATE_FUNC(HelloWorld);//CREATE_FUNC是cocos2d-x中定义的一个宏(作用是：创建一个静态函数"static create()"，该函数可以用来创建层)；
29     
30     
31     
32     // implement the "static create()" method manually
33     
34 };
35 
36 #endif // __HELLOWORLD_SCENE_H__

  1 #include "HelloWorldScene.h"
  2 #include "SimpleAudioEngine.h"
  3 
  4 USING_NS_CC;
  5 /*
  6  说明：createScene()函数式是在游戏应用启动的时候，在AppDelegate中的bool AppDelegate::applicationDidFinishLaunching()函数中通过 auto scene = HelloWorld::createScene()语句调用的。
  7     createScene()中做了三件事情，首先创建了HelloWorld层所在的场景对象，其次创建了HelloWorld层，最后将HelloWorld层添加到场景scene中；
  8  */
  9 Scene* HelloWorld::createScene()
 10 {
 11     // ‘scene‘ is an autorelease object
 12     auto scene = Scene::create();
 13     
 14     // ‘layer‘ is an autorelease object
 15     // 当调用到这句创建层的时候，会调用HelloWorld的实例函数init()，达到初始化HelloWorld层的目的。
 16     auto layer = HelloWorld::create();
 17 
 18     // add layer as a child to scene
 19     scene->addChild(layer);
 20 
 21     // return the scene
 22     return scene;
 23 }
 24 
 25 // on "init" you need to initialize your instance
 26 bool HelloWorld::init()
 27 {
 28     //////////////////////////////
 29     // 1. super init first
 30     // 初始化父类
 31     if ( !Layer::init() )
 32     {
 33         return false;
 34     }
 35     
 36     auto visibleSize = Director::getInstance()->getVisibleSize();
 37     Vec2 origin = Director::getInstance()->getVisibleOrigin();
 38 
 39     /////////////////////////////
 40     // 2. add a menu item with "X" image, which is clicked to quit the program
 41     //    you may modify it.
 42 
 43     // add a "close" icon to exit the progress. it‘s an autorelease object
 44     // 增加一个菜单项，单机的时候退出程序
 45     auto closeItem = MenuItemImage::create(
 46                                            "CloseNormal.png",
 47                                            "CloseSelected.png",
 48                                            CC_CALLBACK_1(HelloWorld::menuCloseCallback, this));
 49     
 50     closeItem->setPosition(Vec2(origin.x + visibleSize.width - closeItem->getContentSize().width/2 ,
 51                                 origin.y + closeItem->getContentSize().height/2));
 52 
 53     // create menu, it‘s an autorelease object
 54     auto menu = Menu::create(closeItem, NULL);
 55     menu->setPosition(Vec2::ZERO);//自定义菜单对象的位置
 56     this->addChild(menu, 1);//把菜单对象添加到当前HelloWorld层上
 57 
 58     /////////////////////////////
 59     // 3. add your codes below...
 60 
 61     // add a label shows "Hello World"
 62     // create and initialize a label
 63     
 64     //添加label标签标题
 65     auto label = Label::createWithTTF("Hello World", "fonts/Marker Felt.ttf", 24);
 66     
 67     // position the label on the center of the screen
 68     label->setPosition(Vec2(origin.x + visibleSize.width/2,
 69                             origin.y + visibleSize.height - label->getContentSize().height));
 70 
 71     // add the label as a child to this layer
 72     this->addChild(label, 1);
 73 
 74     // add "HelloWorld" splash screen"
 75     //添加精灵，也就是cocos2d-x的logo，定义到屏幕中央
 76     auto sprite = Sprite::create("HelloWorld.png");
 77 
 78     // position the sprite on the center of the screen
 79     sprite->setPosition(Vec2(visibleSize.width/2 + origin.x, visibleSize.height/2 + origin.y));
 80 
 81     // add the sprite as a child to this layer
 82     this->addChild(sprite, 0);
 83     
 84     
 85     return true;
 86 }
 87 
 88 // 菜单回调函数(返回主界面)
 89 void HelloWorld::menuCloseCallback(Ref* pSender)
 90 {
 91     //Close the cocos2d-x game scene and quit the application
 92     Director::getInstance()->end();
 93 
 94     #if (CC_TARGET_PLATFORM == CC_PLATFORM_IOS)//IOS表示iOS平台
 95     exit(0);
 96 #endif
 97     
 98     /*To navigate back to native iOS screen(if present) without quitting the application  ,do not use Director::getInstance()->end() and exit(0) as given above,instead trigger a custom event created in RootViewController.mm as below*/
 99     
100     //EventCustom customEndEvent("game_scene_close_event");
101     //_eventDispatcher->dispatchEvent(&customEndEvent);
102     
103     
104     
105     
106 //    PhysicsShape物理引擎类精灵(也属于精灵)
107     
108     
109 //    节点
110     //(1)创建节点
111     Node * chilNode = Node::create();
112     //(2)查找子节点
113     Node *node = node ->getChildByTag(123);
114     //(3)增加新的子节点
115     node->addChild(chilNode,0,123);
116     //(4)删除子节点，并停止该节点上的一切动作
117     node->removeChildByTag(123,true);
118     //(5)通过NOde指针删除节点
119     node ->removeChild(node);
120     //(6)删除所有子节点，并停止这些节点上的一切动作
121     node ->removeAllChildrenWithCleanup(true);
122     //(7)从父节点中删除 node 节点，并停止该节点上的一切动作。
123     node->removeFromParentAndCleanup(true);
124     /*Node重要属性*/
125 //    setPosition; 坐标
126 //    setAnchorPoint(Vce2(0.5,.05)); 锚点
127     
128     
129     
130     
131     //坐标
132 //    Vec2 touchLocation = touch ->getLocationInView();
133 //    Vec2 touchLocation2 = Director::getInstance()->convertToGL(touchLocation);
134     
135     
136 }
137 
138 
139 /**
140  cocos2d-x的事件响应机制：即菜单层最先接收到系统事件，则排在后面的是精灵层，最后是背景层，在事件的传递过程中 ，如果有一个层处理了该事件，则排在后面的层将不再接受到该事件。
141  */