第二章引擎（上）

Cocos2d-x学习笔记

Cocos2d-x 引擎

游戏引擎：一些已经编写好的游戏程序模块（渲染引擎、物理引擎、碰撞检测系统、音效、脚本引擎、动画、人工智能、网络引擎以及场景管理）

游戏引擎主要分为2D和3D，2D主要有Cocos2d-x、Cocos2d-iphone、Corona SDK等，3D主要是Unity3D、ShiVa3D、Marmalade等

Cocos2d-x的HelloWorld程序

初始的HelloWorld程序文件有四个，分别是AppDelegate.h、AppDelegate.cpp、HelloWorld.h、HelloWorld.cpp文件

1. AppDelegate.h

#ifndef  _APP_DELEGATE_H_
#define  _APP_DELEGATE_H_

#include "cocos2d.h"

class  AppDelegate : private cocos2d::Application
{
public:
AppDelegate();//构造函数
virtual ~AppDelegate();//析构函数

virtual void initGLContextAttrs();//初始化OpenGL上下文属性

virtual bool applicationDidFinishLaunching();//游戏启动时调用的函数，初始化导演对象和场景对象

virtual void applicationDidEnterBackground();//游戏进入后台调用的函数

virtual void applicationWillEnterForeground();//游戏进入前台调用的函数
};

#endif // _APP_DELEGATE_H_

2. AppDelegate.cpp

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

USING_NS_CC;//使用的Cocos2d-x中的宏，代替using namespace cocos2d

//定义几种分辨率尺寸
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()
{
}

//设置OpenGL上下文属性
void AppDelegate::initGLContextAttrs()
{
//设置OpenGL上下文属性，现在可以设置6种属性
//red,green,blue,alpha,depth（深度缓存）,stencil（模板缓存）
GLContextAttrs glContextAttrs = {8, 8, 8, 8, 24, 8};

GLView::setGLContextAttrs(glContextAttrs);
}

// 如果要使用包管理更多的包，不要修改或者删除该函数
static int register_all_packages()
{
return 0; //flag for packages manager
}

bool AppDelegate::applicationDidFinishLaunching() {
// 初始化导演对象
auto director = Director::getInstance();
auto glview = director->getOpenGLView();

//判断运行平台
if(!glview) {
#if (CC_TARGET_PLATFORM == CC_PLATFORM_WIN32) || (CC_TARGET_PLATFORM == CC_PLATFORM_MAC) || (CC_TARGET_PLATFORM == CC_PLATFORM_LINUX)
glview = GLViewImpl::createWithRect("HelloWorld", Rect(0, 0, designResolutionSize.width, designResolutionSize.height));
#else
glview = GLViewImpl::create("HelloWorld");
#endif
director->setOpenGLView(glview);
}

// 打开FPS显示
director->setDisplayStats(true);

// 设置FPS
director->setAnimationInterval(1.0 / 60);

// 设定分辨率
glview->setDesignResolutionSize(designResolutionSize.width, designResolutionSize.height, ResolutionPolicy::NO_BORDER);
Size 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();

// 创造一个场景
auto scene = HelloWorld::createScene();

// 运行
director->runWithScene(scene);

return true;
}

// 这个函数将被在app不能使用时调用
void AppDelegate::applicationDidEnterBackground() {
//停止场景中的动画
Director::getInstance()->stopAnimation();

// 如果你使用SimpleAudioEngine播放音乐，则在该方法中暂停
// SimpleAudioEngine::getInstance()->pauseBackgroundMusic();
}

// 这个函数在app被运行时调用
void AppDelegate::applicationWillEnterForeground() {
Director::getInstance()->startAnimation();

// 如果你使用SimpleAudioEngine播放音乐，则在该方法中恢复
// SimpleAudioEngine::getInstance()->resumeBackgroundMusic();
}

3. HelloWorld.h

#ifndef __HELLOWORLD_SCENE_H__
#define __HELLOWORLD_SCENE_H__

#include "cocos2d.h"

class HelloWorld : public cocos2d::Layer//层
{
public:
//创建当前层所在的静态函数
static cocos2d::Scene* createScene();

virtual bool init();

// 菜单回调函数
void menuCloseCallback(cocos2d::Ref* pSender);

// cocos2d-x定义的宏
CREATE_FUNC(HelloWorld);
};

#endif // __HELLOWORLD_SCENE_H__

4. HelloWorld.cpp

#include "HelloWorldScene.h"

USING_NS_CC;

//creatScene函数在游戏启动时调用
Scene* HelloWorld::createScene()
{
// 'scene'是自动释放的对象
auto scene = Scene::create();

// 'layer' 是自动释放的对象
auto layer = HelloWorld::create();

// 将层加入场景
scene->addChild(layer);

// 返回场景
return scene;
}

// 在init函数中初始化实例
bool HelloWorld::init()
{
//////////////////////////////
// 1. 首先初始化父类
if ( !Layer::init() )
{
return false;
}

//得到可视化尺寸
Size visibleSize = Director::getInstance()->getVisibleSize()
//得到可视化远点;
Vec2 origin = Director::getInstance()->getVisibleOrigin();

/////////////////////////////
// 2. 添加一个退出功能
//    you may modify it.

// add a "close" icon to exit the progress. it's an autorelease object
auto closeItem = MenuItemImage::create(
"CloseNormal.png",
"CloseSelected.png",
CC_CALLBACK_1(HelloWorld::menuCloseCallback, this));

closeItem->setPosition(Vec2(origin.x + visibleSize.width - closeItem->getContentSize().width/2 ,
origin.y + closeItem->getContentSize().height/2));

// 创建一个菜单，是自动释放的对象
auto menu = Menu::create(closeItem, NULL);
menu->setPosition(Vec2::ZERO);
this->addChild(menu, 1);

/////////////////////////////
// 3. 添加你自己的代码

// add a label shows "Hello World"
// create and initialize a label

auto label = Label::createWithTTF("Hello World", "fonts/Marker Felt.ttf", 24);

// position the label on the center of the screen
label->setPosition(Vec2(origin.x + visibleSize.width/2,
origin.y + visibleSize.height - label->getContentSize().height));

// add the label as a child to this layer
this->addChild(label, 1);

// add "HelloWorld" splash screen"
auto sprite = Sprite::create("HelloWorld.png");

// position the sprite on the center of the screen
sprite->setPosition(Vec2(visibleSize.width/2 + origin.x, visibleSize.height/2 + origin.y));

// add the sprite as a child to this layer
this->addChild(sprite, 0);

return true;
}

void HelloWorld::menuCloseCallback(Ref* pSender)
{
Director::getInstance()->end();

#if (CC_TARGET_PLATFORM == CC_PLATFORM_IOS)
exit(0);
#endif
}