cocos2dx中的坐标体系

1.UI坐标系和GL坐标系

2.本地坐标与世界坐标

本地坐标是一个相对坐标,是相对于父节点或者你指明的某个节点的相对位置来说的,本地坐标的原点在参考节点的左下角

世界坐标是一个绝对的坐标,是以屏幕的左下角为坐标原点,与GL坐标是重合的.

3.Ui坐标与GL坐标和Node坐标

UI坐标是以UI坐标系来计算的,又叫屏幕坐标,y轴向下,在某些游戏中需要使用到屏幕坐标与GL坐标的转换

GL坐标即世界坐标,是一个绝对的坐标,y轴向上

Node坐标即节点坐标,又叫本地坐标,是一个相对的坐标,是以父节点,或者参考节点的左下角为原点来计算的

4.相关的转换函数:

CCDirector::sharedDirector()->convertToUI();//转换为屏幕坐标
CCDirector::sharedDirector()->convertToGL();//转换为世界坐标

convertToNodeSpace();//转换为本地坐标,又叫节点坐标
convertToWorldSpace();//转换为世界坐标,又叫GL坐标

5.代码处理:

.h文件

#ifndef __T05Coordinate_H__
#define __T05Coordinate_H__

#include "cocos2d.h"
USING_NS_CC;

class T05Coordinate :public CCLayer
{
public:
    static CCScene * scene();
    CREATE_FUNC(T05Coordinate);
    bool init();

    /*触摸事件处理函数*/
    virtual bool ccTouchBegan(CCTouch *pTouch, CCEvent *pEvent);

};

#endif

.cpp文件

#include "T05Coordinate.h"

/*创建场景*/
CCScene *T05Coordinate::scene()
{
    CCScene * scene = CCScene::create();
    T05Coordinate * layer = T05Coordinate::create();
    scene->addChild(layer);
    return scene;
}

bool T05Coordinate::init()
{
    CCLayer::init();
    setTouchEnabled(true);  //打开触摸开关
    setTouchMode(kCCTouchesOneByOne); //设置单点触摸

    /*创建一个空精灵作为背景*/
    CCSprite *big = CCSprite::create();
    /*设置颜色*/
    big->setColor(ccRED);
    big->setAnchorPoint(ccp(0, 0));
    /*设置纹理大小*/
    big->setTextureRect(CCRectMake(0, 0, 150, 150));
    big->setPosition(ccp(100, 100));
    addChild(big);

    CCSprite *little = CCSprite::create();
    little->setColor(ccYELLOW);
    little->setAnchorPoint(ccp(0, 0));
    little->setTextureRect(CCRectMake(0, 0, 50, 50));
    little->setPosition(ccp(100, 100));//即以父类对象为基准,设置到ccp(100,100)的位置
    big->addChild(little);

    /*打印UI坐标,又叫本地坐标,这是相对于它的父类对象而言的,是一个相对坐标*/
    CCLog("little x = %f ,y = %f", little->getPositionX(), little->getPositionY());

    /*父类将子类对象,转换为世界坐标*/
    CCPoint toWorld = big->convertToWorldSpace(little->getPosition());

    CCLog("toWorld x = %f ,y = %f", toWorld.x, toWorld.y);

    CCSprite *little2 = CCSprite::create();
    little2->setColor(ccGREEN);
    little2->setAnchorPoint(ccp(0, 0));
    little2->setTextureRect(CCRectMake(0, 0, 50, 50));
    little2->setPosition(ccp(0, 0));
    addChild(little2);//它的父类对象时CCLayer,因此它的位置是相对于整个屏幕来说的.

    /*父类将子类对象转换为本地坐标,又叫节点坐标*/
    CCPoint toNode = big->convertToNodeSpace(little2->getPosition());/*相对于big对象来说,little2相当于在ccp(-100,-100)*/
    CCLog("little2 x = %f ,y = %f", little2->getPositionX(), little2->getPositionY());
    CCLog("toNode x = %f ,y = %f", toNode.x, toNode.y);

    /*创建一个移动的动作,by表示是绝对位移*/
    CCMoveBy *by = CCMoveBy::create(2, ccp(200, 0));
    CCMoveBy *by2 = (CCMoveBy *)by->reverse();//掉头,反向反转
    /*根据动作,创建一个动作序列*/
    CCSequence *seq = CCSequence::create(by, by2, NULL);
    /*精灵执行动作*/
    //big->runAction(CCRepeatForever::create(seq));

    CCMoveBy *lby = CCMoveBy::create(2, ccp(0, -100));//向下运动
    CCMoveBy *lby2 = (CCMoveBy *)lby->reverse();
    /*变参函数以NULL结尾*/
    CCSequence *lseq = CCSequence::create(lby, lby2, NULL);

    //little->runAction(CCRepeatForever::create(lseq));

    return true;
}

/*触摸事件的处理函数*/
bool T05Coordinate::ccTouchBegan(CCTouch *pTouch, CCEvent *pEvent)
{
    CCLog("ccTouchBegan");
    /*getlocation只有在触摸事件里,其他均是getposition*/
    CCPoint pGl = pTouch->getLocation();//获得世界坐标,又叫GL坐标
    CCLog("GL:x = %f ,y = %f", pGl.x, pGl.y);

    CCPoint pUi = pTouch->getLocationInView();//获得UI坐标,UI坐标又叫屏幕坐标系,在坦克大战中可以用到转换
    CCLog("UI:x = %f ,y = %f", pUi.x, pUi.y);

    CCPoint toUi = CCDirector::sharedDirector()->convertToUI(pGl);//将世界坐标转换为Ui坐标
    CCLog("ToUix = %f ,y = %f", toUi.x, toUi.y);

    CCPoint toGl = CCDirector::sharedDirector()->convertToGL(pUi);//将Ui坐标转换为世界坐标
    CCLog("ToGlx = %f ,y = %f", toGl.x, toGl.y);

    CCPoint node = this->convertToNodeSpace(pGl);//将Gl坐标转换为节点坐标,又叫本地坐标
    CCLog("Node:x = %f ,y = %f", node.x, node.y);


    return false;
}