Cocos2d适应屏幕分辨率

我使用的版本是cocos2d-2.0-x-2.0.4，cocos2dx-2.0版本对多分辨率适配提供了很好的支持，使用起来比1.0版本要简单些，1.0版本的适配可以参考这篇博文。
1. 做2.0版本的适配首先需要了解下面这些知识。
(1)适配策略
2.0版本提供了三种适配策略：
kResolutionNoBorder：超出屏幕的部分会被裁剪，两侧没有黑边，铺满屏幕，按图片原始比例显示，图片不变形。
kResolutionShowAll：整个游戏界面是可见的，会按原始比例进行缩放，图片不变形，但两侧可能会留有黑边，不铺满屏幕。
kResolutionExactFit：整个游戏界面是可见的，图片可能会进行拉伸或者压缩处理，铺满屏幕，图片会变形。
可以根据自己的要求选择。
(2)VisibleSize和VisibleOrigin
getVisibleSize：表示获得视口(可视区域)的大小，如果DesignResolutionSize跟屏幕尺寸一样大，则getVisibleSize等于getWinSize。
getVisibleOrigin：表示可视区域的起点坐标，这在处理相对位置的时候非常有用，确保节点在不同分辨率下的位置一致。
(3)DesignResolutionSize
DesignResolutionSize是一个比较重要的概念，其实2.0版本的适配跟1.0版本原理差不多，都是按比例进行缩放。这个DesignResolutionSize表示设计方案，就是你的游戏完美支持的分辨率方案，一般根据图片资源的尺寸来定，自适配时会按照这个分辨率计算出缩放因子。因此，这个值也应该是动态的，如果是横屏游戏则高度肯定是铺满屏幕的，宽度也要尽可能的铺满屏幕，因此应该选择宽高比最大的作为设计分辨率，下面的demo会给出使用方法。
(4)设置相对位置
在游戏中使用相对位置设置坐标的好处是显而易见的，这样就不需要为每个分辨率都定义一套坐标了。首先得定义一些参考点，引擎的TestCpp例子中就提供了一种方法，以屏幕上可视区域的9个点作为参考点，相当于在该矩形内写一个米字，这9个点分别是：左上、左、左下、下、右下、右、右上、上、中心。

2. 下面来实现一个简单的demo，首先创建一个win32工程，这个就不详述了。
(1)创建一个AppMacros.h文件，定义了一些宏，源码如下：

#ifndef __APPMACROS_H__
#define __APPMACROS_H__

#include "cocos2d.h"

typedef struct tagResource
{
    cocos2d::CCSize size;
    char directory[100];
}Resource;

//可用的资源尺寸
static Resource smallResource  =  { cocos2d::CCSizeMake(480, 320),   "iphone" };
static Resource mediumResource =  { cocos2d::CCSizeMake(1024, 768),  "ipad"   };
static Resource largeResource  =  { cocos2d::CCSizeMake(2048, 1536), "ipadhd" };

//设计方案
static cocos2d::CCSize smallDesignResolutionSize = cocos2d::CCSizeMake(480.0f, 320.0f);
static cocos2d::CCSize mediumDesignResolutionSize = cocos2d::CCSizeMake(1024.0f, 768.0f);
static cocos2d::CCSize largeDesignResolutionSize = cocos2d::CCSizeMake(2048.0f, 1536.0f);

//缩放因子，主要给文字标签使用
#define SCALE_FACTOR  (cocos2d::CCEGLView::sharedOpenGLView()->getDesignResolutionSize().width / smallResource.size.width)

#endif

(2)接下来修改AppDelegate.cpp文件的applicationDidFinishLaunching函数，添加以下代码：

bool AppDelegate::applicationDidFinishLaunching()
{
    // initialize director
    CCDirector *pDirector = CCDirector::sharedDirector();
    CCEGLView *pEGLView = CCEGLView::sharedOpenGLView();
    pDirector->setOpenGLView(pEGLView);

    CCSize frameSize = pEGLView->getFrameSize();
    float ratio = frameSize.width / frameSize.height;
    float ratio1 = largeDesignResolutionSize.width / largeDesignResolutionSize.height;
    float ratio2 = mediumDesignResolutionSize.width / mediumDesignResolutionSize.height;
    float ratio3 = smallDesignResolutionSize.width / smallDesignResolutionSize.height;
    float d1 = abs (ratio - ratio1);
    float d2 = abs (ratio - ratio2);
    float d3 = abs (ratio - ratio3);
    std::map< float , CCSize> designSize;
    designSize[d1] = largeDesignResolutionSize;
    designSize[d2] = mediumDesignResolutionSize;
    designSize[d3] = smallDesignResolutionSize;
    std::map< float , CCSize>::reverse_iterator iter = designSize.rbegin();
    //得到key最大的，因此我这里是横屏，所以以高度为基准，为了确保缩放后宽度能全屏，所以选取宽高比最大的为设计方案
    CCSize designResolutionSize = iter->second;

    //pEGLView->setDesignResolutionSize(designResolutionSize.width, designResolutionSize.height, kResolutionNoBorder);
    pEGLView->setDesignResolutionSize(designResolutionSize.width, designResolutionSize.height, kResolutionShowAll);
    //pEGLView->setDesignResolutionSize(designResolutionSize.width, designResolutionSize.height, kResolutionExactFit);

    if (frameSize.height > mediumResource.size.height)
    {
        CCFileUtils::sharedFileUtils()->setResourceDirectory(largeResource.directory);
        pDirector->setContentScaleFactor(largeResource.size.height/designResolutionSize.height);
    }
    else if (frameSize.height > smallResource.size.height)
    {
        CCFileUtils::sharedFileUtils()->setResourceDirectory(mediumResource.directory);
        pDirector->setContentScaleFactor(mediumResource.size.height/designResolutionSize.height);
    }
    else
    {
        CCFileUtils::sharedFileUtils()->setResourceDirectory(smallResource.directory);
        pDirector->setContentScaleFactor(smallResource.size.height/designResolutionSize.height);
    }

    pDirector->setDisplayStats( true );

    pDirector->setAnimationInterval(1.0 / 60);

    CCScene *pScene = HelloWorld::scene();

    pDirector->runWithScene(pScene);

    return true ;
}

(3)创建VisibleRect.h和VisibleRect.cpp文件，封装了获取那9个点坐标的函数，比较简单。代码如下：
VisibleRect.h

#ifndef __VISIBLERECT_H__
#define __VISIBLERECT_H__

#include "cocos2d.h"
USING_NS_CC;

class VisibleRect
{
public :
    static CCRect getVisibleRect();

    static CCPoint left();
    static CCPoint right();
    static CCPoint top();
    static CCPoint bottom();
    static CCPoint center();
    static CCPoint leftTop();
    static CCPoint rightTop();
    static CCPoint leftBottom();
    static CCPoint rightBottom();
private :
    static void lazyInit();
    static CCRect s_visibleRect;
};

#endif

VisibleRect.cpp

#include "VisibleRect.h"

CCRect VisibleRect::s_visibleRect;

void VisibleRect::lazyInit()
{
    if (s_visibleRect.size.width == 0.0f && s_visibleRect.size.height == 0.0f)
    {
        CCEGLView* pEGLView = CCEGLView::sharedOpenGLView();
        s_visibleRect.origin = pEGLView->getVisibleOrigin();
        s_visibleRect.size = pEGLView->getVisibleSize();
    }
}

CCRect VisibleRect::getVisibleRect()
{
    lazyInit();
    return CCRectMake(s_visibleRect.origin.x, s_visibleRect.origin.y, s_visibleRect.size.width, s_visibleRect.size.height);
}

CCPoint VisibleRect::left()
{
    lazyInit();
    return ccp(s_visibleRect.origin.x, s_visibleRect.origin.y + s_visibleRect.size.height/2);
}

CCPoint VisibleRect::right()
{
    lazyInit();
    return ccp(s_visibleRect.origin.x+s_visibleRect.size.width, s_visibleRect.origin.y + s_visibleRect.size.height/2);
}

CCPoint VisibleRect::top()
{
    lazyInit();
    return ccp(s_visibleRect.origin.x + s_visibleRect.size.width/2, s_visibleRect.origin.y + s_visibleRect.size.height);
}

CCPoint VisibleRect::bottom()
{
    lazyInit();
    return ccp(s_visibleRect.origin.x + s_visibleRect.size.width/2, s_visibleRect.origin.y);
}

CCPoint VisibleRect::center()
{
    lazyInit();
    return ccp(s_visibleRect.origin.x + s_visibleRect.size.width/2, s_visibleRect.origin.y + s_visibleRect.size.height/2);
}

CCPoint VisibleRect::leftTop()
{
    lazyInit();
    return ccp(s_visibleRect.origin.x, s_visibleRect.origin.y + s_visibleRect.size.height);
}

CCPoint VisibleRect::rightTop()
{
    lazyInit();
    return ccp(s_visibleRect.origin.x + s_visibleRect.size.width, s_visibleRect.origin.y + s_visibleRect.size.height);
}

CCPoint VisibleRect::leftBottom()
{
    lazyInit();
    return s_visibleRect.origin;
}

CCPoint VisibleRect::rightBottom()
{
    lazyInit();
    return ccp(s_visibleRect.origin.x + s_visibleRect.size.width, s_visibleRect.origin.y);
}

(4)修改HelloWorldScene.cpp的init函数，使用相对位置设置坐标。

bool HelloWorld::init()
{
    if ( !CCLayer::init() )
    {
        return false ;
    }
    CCMenuItemImage *pCloseItem = CCMenuItemImage::create(
                                        "CloseNormal.png" ,
                                        "CloseSelected.png" ,
                                        this ,
                                        menu_selector(HelloWorld::menuCloseCallback));

    pCloseItem->setPosition(ccpAdd(VisibleRect::rightBottom(),
                                ccp(-pCloseItem->getContentSize().width/2, pCloseItem->getContentSize().height/2)));

    CCMenu* pMenu = CCMenu::create(pCloseItem, NULL);
    pMenu->setPosition(CCPointZero);
    this ->addChild(pMenu, 1);

    CCLabelTTF* pLabel = CCLabelTTF::create( "Hello World" , "Arial" , SCALE_FACTOR * 24);
    pLabel->setPosition(ccpAdd(VisibleRect::top(),
                            ccp(0, -pLabel->getContentSize().height)));
    this ->addChild(pLabel, 1);

    CCSprite* pSprite = CCSprite::create( "HelloWorld.png" );
    pSprite->setPosition(VisibleRect::center());
    this ->addChild(pSprite, 0);

    CCSprite *pLogoSprite = CCSprite::create( "icon.png" );
    pLogoSprite->setAnchorPoint( ccp(0, 0.5) );
    pLogoSprite->setPosition(ccpAdd(VisibleRect::left(), ccp(50, 0)));
    this ->addChild(pLogoSprite, 0);

    return true ;
}

(5)创建窗口，main.cpp的主要内容：

AppDelegate app;
CCEGLView* eglView = CCEGLView::sharedOpenGLView();
    //eglView->setFrameSize(2048, 1536);
    //eglView->setFrameSize(480, 320);
    //eglView->setFrameSize(800, 480);
    //eglView->setFrameSize(1024, 768);
    //eglView->setFrameSize(1280, 800);
    eglView->setFrameSize(1280, 768);
    //eglView->setFrameSize(960, 640);
    eglView->setFrameZoomFactor(0.5f);

int ret = CCApplication::sharedApplication()->run();

OK，到此为止，代码部分已经完成了，下面看看在各种分辨率和不同策略下的效果图：
1. kResolutionShowAll策略：
(1)2048×1536

(2)1024×768

(3)480×320

(4)800×480

(5)1280×800

(6)960×640

2. kResolutionExactFit策略
1280×768分辨率

3. kResolutionNoBorder策略
1280×768分辨率