Cocos2d入门--3--小球运动

本章直接上源代码。内容不难，主要就是

HelloWorldScene.h文件：

 1 #ifndef __HELLOWORLD_SCENE_H__
 2 #define __HELLOWORLD_SCENE_H__
 3 
 4 #include "cocos2d.h"
 5 
 6 class HelloWorld : public cocos2d::Layer
 7 {
 8 protected:
 9     float _angle;
10     cocos2d::Vec2 _vec;
11 public:
12     static cocos2d::Scene* createScene();
13 
14     virtual bool init();
15     
16     // a selector callback
17     void menuCloseCallback(cocos2d::Ref* pSender);
18     
19     // implement the "static create()" method manually
20     CREATE_FUNC(HelloWorld);
21     
22     virtual void update(float dt);
23 private:
24     //获取屏幕可视范围
25     float width_L;
26     float width_R;
27     cocos2d::DrawNode* ball;
28 };
29 
30 #endif // __HELLOWORLD_SCENE_H__

HelloWorldScene.cpp文件：

 1 // on "init" you need to initialize your instance
 2 bool HelloWorld::init()
 3 {
 4     //////////////////////////////
 5     // 1. super init first
 6     if ( !Layer::init() )
 7     {
 8         return false;
 9     }
10     
11     Size visibleSize = Director::getInstance()->getVisibleSize();
12     Vec2 origin = Director::getInstance()->getVisibleOrigin();
13     width_L = origin.x;
14     width_R = origin.x + visibleSize.width;
15     
16     ball = DrawNode::create();
17     ball -> drawDot(Vec2(0, 0), 4, Color4F(1.0f, 1.0f, 1.0f, 1.0f));
18     
19     addChild(ball);
20     ball -> setPosition(origin.x + visibleSize.width/2,origin.y + visibleSize.height/2);
21     
22     //action相关的运动我们一般不是用来做游戏的运动，一般用来做游戏的变化效果。因为action不能很好的用来表现出游戏的效果
23 //    dot -> runAction(RepeatForever::create(MoveBy::create(0.2, _vec*100)));
24     //
25     scheduleUpdate();
26     return true;
27 }
28 
29 void HelloWorld::update(float dt){
30     ball -> setPositionX(ball->getPositionX()+5);
31     if (ball->getPositionX()<width_L-ball->getContentSize().width/2
32         || ball->getPositionX()>width_R+ball->getContentSize().width/2) {
33         ball->setPositionX(-ball->getContentSize().width/2);
34     }
35 }

然后实现的效果：