cocos2dx3.3开发FlappyBird总结八：载入场景LoadingScene

载入场景的目的是预加载资源，也就是在场景进入时，把资源加载到内存中：

// 重写onEnter方法，场景载入时，会调用此方法，此外我们还需要调一下父类的方法，这个是API说明的，照做就行。// 方法其实功能是很简单的，就是先显示一张splash图片，然后异步加载图片资源，这个addImageAsync方法是引擎内部提供的API，可异步加载，这样就不会阻塞主线程了。void LoadingScene::onEnter() {  Layer::onEnter();  // Add the splash screen image  auto background = Sprite::create("splash.png");  auto size = Director::getInstance()->getVisibleSize();  auto origin = Director::getInstance()->getVisibleOrigin();  background->setPosition(origin.x + size.width / 2, origin.y + size.height / 2);  this->addChild(background);  // Start to load texture async  auto texture = Director::getInstance()->getTextureCache();  texture->addImageAsync("atlas.png",                         CC_CALLBACK_1(LoadingScene::onLoadFinishedCallback, this));}

加载完成后，就是加载音频文件，这里是同步加载的，如果资源很多的话，会卡的。加载完成后，就进入到WelcomeScene了。

void LoadingScene::onLoadFinishedCallback(cocos2d::Texture2D *texture) {  // Load the atlas  AtlasLoader::getInstance()->loadAtlas("atlas.txt", texture);  // Preload effect music.  // Here is not the best way to load all music files,  // in real projects, you should find a better way to do.  CocosDenshion::SimpleAudioEngine::getInstance()->preloadEffect("sfx_die.ogg");  CocosDenshion::SimpleAudioEngine::getInstance()->preloadEffect("sfx_hit.ogg");  CocosDenshion::SimpleAudioEngine::getInstance()->preloadEffect("sfx_point.ogg");  CocosDenshion::SimpleAudioEngine::getInstance()->preloadEffect("sfx_swooshing.ogg");  CocosDenshion::SimpleAudioEngine::getInstance()->preloadEffect("sfx_wing.ogg");  // Now the task of the loading scene has finished,  // auto enter into the welcome scene  auto scene = TransitionFade::create(1.0f, WelcomeScene::createScene());  Director::getInstance()->replaceScene(scene);}

下一步：说说欢迎场景