1. 首先，声明一个2个大小的sprite数组
class GameScreen : public cocos2d::Layer { public: ... cocos2d::Sprite *backgroundSpriteArray[2]; };
2. 完成初始化，1张图片用于当前显示，另1张用于滚动到下一张
bool GameScreen::init() { ////////////////////////////// // 1. super init first if ( !Layer::init() ) { return false; } Size visibleSize = Director::getInstance()->getVisibleSize(); Point origin = Director::getInstance()->getVisibleOrigin(); ... for (int i = 0; i < 2; i ++) { backgroundSpriteArray[i] = Sprite::create("GameScreen/Game_Screen_Background.png"); backgroundSpriteArray[i]->setPosition(Point((visibleSize.width / 2), (-1 * visibleSize.height * i) + (visibleSize.height / 2))); this->addChild(backgroundSpriteArray[i], -2); } ... }
3. 声明update方法表示每帧的更新
class GameScreen : public cocos2d::Layer { public: ... void update(float dt); };
4. 实现update方法
void GameScreen::update(float dt) { Size visibleSize = Director::getInstance()->getVisibleSize(); Point origin = Director::getInstance()->getVisibleOrigin(); for (int i = 0; i < 2; i ++) { if (backgroundSpriteArray[i]->getPosition().y >= visibleSize.height + (visibleSize.height / 2) -1) { backgroundSpriteArray[i]->setPosition(Point((visibleSize.width / 2) + origin.x, (-1 * visibleSize.height) + (visibleSize.height / 2))); } } for (int i = 0; i < 2; i ++) { backgroundSpriteArray[i]->setPosition(Point(backgroundSpriteArray[i]->getPosition().x, backgroundSpriteArray[i]->getPosition().y + (0.75 * visibleSize.height * dt))); } ... }
5. 触发默认的update方法
bool GameScreen::init() { ... this->scheduleUpdate(); ... }
