Cocos2d-x实例：设置背景音乐与音效-HelloWorld场景实现

HelloWorld场景就是游戏中的主菜单场景。HelloWorld.h文件代码如下：

#define __HELLOWORLD_SCENE_H__

#include "cocos2d.h"
#include "SimpleAudioEngine.h"											①
#include "SettingScene.h"

class HelloWorld : public cocos2d::Layer
{
public:
	static cocos2d::Scene* createScene();

	virtual bool init();  													②
	virtual void onEnter();
	virtual void onEnterTransitionDidFinish();
	virtual void onExit();
	virtual void onExitTransitionDidStart();
	virtual void cleanup();													③

	void menuItemHelpCallback(cocos2d::Ref* pSender);
	void menuItemStartCallback(cocos2d::Ref* pSender);
	void menuItemSettingCallback(cocos2d::Ref* pSender);
	CREATE_FUNC(HelloWorld);
};

bool HelloWorld::init()
{
	if ( !Layer::init() )
	{
		return false;
	}

	log("HelloWorld init");

	Size visibleSize = Director::getInstance()->getVisibleSize();
	Point origin = Director::getInstance()->getVisibleOrigin();

	Sprite *bg = Sprite::create("background.png");

	bg->setPosition(Point(origin.x + visibleSize.width/2,
		origin.y + visibleSize.height /2));
	this->addChild(bg);

	//开始精灵
	Sprite *startSpriteNormal = Sprite::create("start-up.png");
	Sprite *startSpriteSelected = Sprite::create("start-down.png");

	MenuItemSprite *startMenuItem = MenuItemSprite::create(startSpriteNormal,
		startSpriteSelected,
		CC_CALLBACK_1(HelloWorld::menuItemStartCallback, this));
	startMenuItem->setPosition(Director::getInstance()->convertToGL(Point(700, 170)));

	// 设置图片菜单
	MenuItemImage *settingMenuItem = MenuItemImage::create(
		"setting-up.png",
		"setting-down.png",
		CC_CALLBACK_1(HelloWorld::menuItemSettingCallback, this));
	settingMenuItem->setPosition(Director::getInstance()->convertToGL(Point(480, 400)));

	// 帮助图片菜单
	MenuItemImage *helpMenuItem = MenuItemImage::create(
		"help-up.png",
		"help-down.png",
		CC_CALLBACK_1(HelloWorld::menuItemHelpCallback, this));
	helpMenuItem->setPosition(Director::getInstance()->convertToGL(Point(860, 480)));

	Menu* mu = Menu::create(startMenuItem, settingMenuItem, helpMenuItem, NULL);
	mu->setPosition(Point::ZERO);
	this->addChild(mu);

	return true;
}

void HelloWorld::menuItemSettingCallback(Ref* pSender)
{
	auto sc = Setting::createScene();
	auto reScene = TransitionJumpZoom::create(1.0f, sc);
	Director::getInstance()->pushScene(reScene);
	SimpleAudioEngine::getInstance()->playEffect("sound/Blip.wav");					②
}

void HelloWorld::menuItemHelpCallback(Ref* pSender)
{
	MenuItem* item = (MenuItem*)pSender;
	log("Touch Help %p", item);
	SimpleAudioEngine::getInstance()->playEffect("sound/Blip.wav");					③
}

void HelloWorld::menuItemStartCallback(Ref* pSender)
{
	MenuItem* item = (MenuItem*)pSender;
	log("Touch Start %p", item);
	SimpleAudioEngine::getInstance()->playEffect("sound/Blip.wav");					④
}

void HelloWorld::onEnter()
{
	Layer::onEnter();
	log("HelloWorld onEnter");
}

void HelloWorld::onEnterTransitionDidFinish()
{
	Layer::onEnterTransitionDidFinish();
	log("HelloWorld onEnterTransitionDidFinish");
	//播放
	SimpleAudioEngine::getInstance()->playBackgroundMusic("sound/Jazz.mp3", true);		⑤
}

void HelloWorld::onExit()
{
	Layer::onExit();
	log("HelloWorld onExit");
}

void HelloWorld::onExitTransitionDidStart()
{
	Layer::onExitTransitionDidStart();
	log("HelloWorld onExitTransitionDidStart");
}

void HelloWorld::cleanup()
{
	Layer::cleanup();
	log("HelloWorld cleanup");
	//停止
	SimpleAudioEngine::getInstance()->stopBackgroundMusic("sound/Jazz.mp3");			⑥
}

上述代码第①行using namespace CocosDenshion是使用命名空间CocosDenshion，它是CocosDenshion引擎所需要的。代码②、③、④行SimpleAudioEngine::getInstance()->playEffect("sound/Blip.wav")是在点击菜单时候播放音效。第⑤行代码是onEnterTransitionDidFinish()函数中播放背景音乐。第⑥行代码是cleanup()函数中停止播放背景音乐。

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