主菜单场景，主要实现进入游戏时的初始界面，它包括6个场景入口的菜单项：开始游戏，排行榜，帮助，设置，关于，退出

下面是MainLayer的头文件

#ifndef  __MAIN_LAYER_H_
#define __MAIN_LAYER_H_

#include "cocos2d.h"
#include "GameSceneManager.h"

using namespace cocos2d;

class MainLayer :public Layer//主界面主要包含6个菜单项
{
public:
	virtual bool init();
	int randNum();//产生随机数的方法
	void initSound();//加载游戏音效的方法
	void menuCallBack0(Ref* pSender);//切换到选择游戏场景
	void menuCallBack1(Ref* pSender);//切换到排行榜场景
	void menuCallBack2(Ref* pSender);//切换到游戏设置场景
	void menuCallBack3(Ref* pSender);//切换到游戏帮助场景
	void menuCallBack4(Ref* pSender);//切换到游戏关于场景
	void menuCallBack5(Ref* pSender);//退出游戏的菜单回调方法
	void initTitle();//更新标题
	CREATE_FUNC(MainLayer);
public:
	Sprite* backGround;
	NodeGrid* effectNode;//网格节点，用来实现3D水波涟漪特效
	static bool musicFlag;
	static bool soundFlag;
	GameSceneManager* sceneManager;
};
#endif

MainLayer.cpp文件，其中文件中的某些菜单项，暂时没有实现其功能，后续补充修改。

#include "MainLayer.h"
#include "SimpleAudioEngine.h"

bool MainLayer::musicFlag = true;
bool MainLayer::soundFlag = true;

bool MainLayer::init()//主菜单界面的初始化
{
	if (!Layer::init())
		return false;

	//设置随机种子，该方法基本可以实现真正的随机
	timeval psv;
	gettimeofday(&psv,nullptr);
	unsigned long int seed = psv.tv_sec * 1000 + psv.tv_usec / 1000;
	srand(seed);

	auto visibleSize = Director::getInstance()->getVisibleSize();
	auto origin = Director::getInstance()->getVisibleOrigin();
	int n = randNum();//获取随机数（0-4），产生随机背景
	if (n % 2 == 0)
		backGround = Sprite::create("pic/morning.png");
	else
		backGround = Sprite::create("pic/night.png");
	backGround->setAnchorPoint(Vec2(0,0));//设置背景锚点在左下角
	backGround->setPosition(origin.x,origin.y + visibleSize.height - backGround->getContentSize().height);
	this->addChild(backGround,0);

	if (MainLayer::musicFlag)
		CocosDenshion::SimpleAudioEngine::getInstance()->playBackgroundMusic("sounds/playscene.mp3",true);
	
	auto floor = Sprite::create("pic/floor.png");
	floor->setAnchorPoint(Vec2(0,0));
	floor->setPosition(origin);
	this->addChild(floor);
	floor->runAction(RepeatForever::create(Sequence::create(MoveTo::create(0.5f,Vec2(-120,0)),MoveTo::create(0,Vec2(0,nullptr)));

	//菜单项加载
	auto menuItemStart = MenuItemImage::create("button/start.png","button/start_off.png",CC_CALLBACK_1(MainLayer::menuCallBack0,this));
	menuItemStart->setPosition(Vec2(150,600));

	auto menuItemRank = MenuItemImage::create("button/rank.png","button/rank_off.png",CC_CALLBACK_1(MainLayer::menuCallBack1,this));
	menuItemRank->setPosition(Vec2(390,600));

	auto menuItemSet = MenuItemImage::create("button/set.png","button/set_off.png",CC_CALLBACK_1(MainLayer::menuCallBack2,this));
	menuItemSet->setPosition(Vec2(150,450));

	auto menuItemHelp = MenuItemImage::create("button/help.png","button/help_off.png",CC_CALLBACK_1(MainLayer::menuCallBack3,this));
	menuItemHelp->setPosition(Vec2(390,450));

	auto menuItemAbout = MenuItemImage::create("button/about.png","button/about_off.png",CC_CALLBACK_1(MainLayer::menuCallBack4,this));
	menuItemAbout->setPosition(Vec2(150,300));

	auto menuItemExit = MenuItemImage::create("button/exit.png","button/exit_off.png",CC_CALLBACK_1(MainLayer::menuCallBack5,this));
	menuItemExit->setPosition(Vec2(390,300));

	auto mn = Menu::create(menuItemStart,menuItemRank,menuItemSet,menuItemHelp,menuItemAbout,menuItemExit,nullptr);
	mn->setPosition(Vec2::ZERO);
	this->addChild(mn,10);

	effectNode = NodeGrid::create();
	this->addChild(effectNode,10);//加入网格节点
	auto title = Sprite::create("pic/title.png");
	title->setPosition(Vec2(270,800));
	effectNode->addChild(title);//将精灵添加到网格节点中
	Director::getInstance()->setDepthTest(false);//关闭深度检测
	effectNode->runAction(RepeatForever::create(Ripple3D::create(2.0f,Size(32,24),Vec2(270,800),360,4,5)));
	return true;
}


int MainLayer::randNum()
{
	int num = random(0,4);//根据产生的数，确定要加载的背景图片
	return num;
}

void MainLayer::initTitle()
{
	auto title = Sprite::create("pic/title.png");
	title->setPosition(270,800);
	this->addChild(title,10);
	this->removeChild(effectNode);
}

void MainLayer::menuCallBack0(Ref* pSender)
{

}

void MainLayer::menuCallBack1(Ref* pSender)
{
	initTitle();
	sceneManager->goToRankBirdScene();
}

void MainLayer::menuCallBack2(Ref* pSender)
{

}

void MainLayer::menuCallBack3(Ref* pSender)
{

}
void MainLayer::menuCallBack4(Ref* pSender)
{

}
void MainLayer::menuCallBack5(Ref* pSender)
{

}

主菜单布景实现的效果图：