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：

1. #define __HELLOWORLD_SCENE_H__
2. #include "cocos2d.h"
3. #include "SimpleAudioEngine.h"                                          ①
4. #include "SettingScene.h"
5. class HelloWorld : public cocos2d::Layer
6. {
7. public:
8. static cocos2d::Scene* createScene();
9. virtual bool init();                                                    ②
10. virtual void onEnter();
11. virtual void onEnterTransitionDidFinish();
12. virtual void onExit();
13. virtual void onExitTransitionDidStart();
14. virtual void cleanup();                                                 ③
15. void menuItemHelpCallback(cocos2d::Ref* pSender);
16. void menuItemStartCallback(cocos2d::Ref* pSender);
17. void menuItemSettingCallback(cocos2d::Ref* pSender);
18. CREATE_FUNC(HelloWorld);
19. };
20. bool HelloWorld::init()
21. {
22. if ( !Layer::init() )
23. {
24. return false;
25. }
26. log("HelloWorld init");
27. Size visibleSize = Director::getInstance()->getVisibleSize();
28. Point origin = Director::getInstance()->getVisibleOrigin();
29. Sprite *bg = Sprite::create("background.png");
30. bg->setPosition(Point(origin.x + visibleSize.width/2,
31. origin.y + visibleSize.height /2));
32. this->addChild(bg);
33. //开始精灵
34. Sprite *startSpriteNormal = Sprite::create("start-up.png");
35. Sprite *startSpriteSelected = Sprite::create("start-down.png");
36. MenuItemSprite *startMenuItem = MenuItemSprite::create(startSpriteNormal,
37. startSpriteSelected,
38. CC_CALLBACK_1(HelloWorld::menuItemStartCallback, this));
39. startMenuItem->setPosition(Director::getInstance()->convertToGL(Point(700, 170)));
40. // 设置图片菜单
41. MenuItemImage *settingMenuItem = MenuItemImage::create(
42. "setting-up.png",
43. "setting-down.png",
44. CC_CALLBACK_1(HelloWorld::menuItemSettingCallback, this));
45. settingMenuItem->setPosition(Director::getInstance()->convertToGL(Point(480, 400)));
46. // 帮助图片菜单
47. MenuItemImage *helpMenuItem = MenuItemImage::create(
48. "help-up.png",
49. "help-down.png",
50. CC_CALLBACK_1(HelloWorld::menuItemHelpCallback, this));
51. helpMenuItem->setPosition(Director::getInstance()->convertToGL(Point(860, 480)));
52. Menu* mu = Menu::create(startMenuItem, settingMenuItem, helpMenuItem, NULL);
53. mu->setPosition(Point::ZERO);
54. this->addChild(mu);
55. return true;
56. }
57. void HelloWorld::menuItemSettingCallback(Ref* pSender)
58. {
59. auto sc = Setting::createScene();
60. auto reScene = TransitionJumpZoom::create(1.0f, sc);
61. Director::getInstance()->pushScene(reScene);
62. SimpleAudioEngine::getInstance()->playEffect("sound/Blip.wav");                  ②
63. }
64. void HelloWorld::menuItemHelpCallback(Ref* pSender)
65. {
66. MenuItem* item = (MenuItem*)pSender;
67. log("Touch Help %p", item);
68. SimpleAudioEngine::getInstance()->playEffect("sound/Blip.wav");                  ③
69. }
70. void HelloWorld::menuItemStartCallback(Ref* pSender)
71. {
72. MenuItem* item = (MenuItem*)pSender;
73. log("Touch Start %p", item);
74. SimpleAudioEngine::getInstance()->playEffect("sound/Blip.wav");                  ④
75. }
76. void HelloWorld::onEnter()
77. {
78. Layer::onEnter();
79. log("HelloWorld onEnter");
80. }
81. void HelloWorld::onEnterTransitionDidFinish()
82. {
83. Layer::onEnterTransitionDidFinish();
84. log("HelloWorld onEnterTransitionDidFinish");
85. //播放
86. SimpleAudioEngine::getInstance()->playBackgroundMusic("sound/Jazz.mp3", true);       ⑤
87. }
88. void HelloWorld::onExit()
89. {
90. Layer::onExit();
91. log("HelloWorld onExit");
92. }
93. void HelloWorld::onExitTransitionDidStart()
94. {
95. Layer::onExitTransitionDidStart();
96. log("HelloWorld onExitTransitionDidStart");
97. }
98. void HelloWorld::cleanup()
99. {
100. Layer::cleanup();
101. log("HelloWorld cleanup");
102. //停止
103. SimpleAudioEngine::getInstance()->stopBackgroundMusic("sound/Jazz.mp3");         ⑥
104. }

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。

更多内容请关注Cocos2d-x系列图书《Cocos2d-x实战（卷Ⅰ）：C++开发》

本书交流讨论网站：http://www.cocoagame.net

欢迎加入cocos2d-x技术讨论群：257760386、327403678