cocos2dx 2.1.4 程序运行脉络解析3—解析CCEGLView

这篇主要是要解决上一篇遗留下的突出问题：

回忆上两篇分析程序运行时有这么几个函数很容易混淆，我按照顺序先一次将他们列出来：

main函数：

CCEGLView* eglView = CCEGLView::sharedOpenGLView();

    eglView->setViewName("HelloCpp");
    eglView->setFrameSize(2048, 1536);///////设置frame的大小，标号1
    // The resolution of ipad3 is very large. In general, PC's resolution is smaller than it.
    // So we need to invoke 'setFrameZoomFactor'(only valid on desktop(win32, mac, linux)) to make the window smaller.
    eglView->setFrameZoomFactor(0.4f);///////设置view frame的缩放比例，标号2

AppDelegate::applicationDidFinishLaunching()函数：

    CCDirector* pDirector = CCDirector::sharedDirector();//初始化director
    CCEGLView* pEGLView = CCEGLView::sharedOpenGLView();
    pDirector->setOpenGLView(pEGLView);///////设置关联到director中并设置director的winSizeInPoints属性与view的resolutionSize相等，标号3
// Set the design resolution
pEGLView->setDesignResolutionSize(designResolutionSize.width, designResolutionSize.height, kResolutionNoBorder);///////设置view的分辨率，标号4

... ...

pDirector->setContentScaleFactor(...)///////设置director的缩放比例，标号5

归纳一下，对于缩放比例一共有3种：

1.CCEGLViewProtocol中的 m_fScaleX，m_fScaleY

2.CCEGLView 的 frameZoomFactor：m_fFrameZoomFactor

3.CCDirector的 m_fContentScaleFactor

我带着分不清这3中scale的疑惑来解析下面的东西：

好！先看CCEGLViewProtocol

enum ResolutionPolicy { // The entire application is visible in the specified area without trying to preserve the original aspect ratio. // Distortion can occur, and the application may appear stretched or compressed. kResolutionExactFit, // The entire application fills the specified area, without distortion but possibly with some cropping, // while maintaining the original aspect ratio of the application. kResolutionNoBorder, // The entire application is visible in the specified area without distortion while maintaining the original // aspect ratio of the application. Borders can appear on two sides of the application. kResolutionShowAll, // The application takes the height of the design resolution size and modifies the width of the internal // canvas so that it fits the aspect ratio of the device // no distortion will occur however you must make sure your application works on different // aspect ratios kResolutionFixedHeight, // The application takes the width of the design resolution size and modifies the height of the internal // canvas so that it fits the aspect ratio of the device // no distortion will occur however you must make sure your application works on different // aspect ratios kResolutionFixedWidth, kResolutionUnKnown, }; NS_CC_BEGIN #define CC_MAX_TOUCHES 5 class EGLTouchDelegate; class CCSet; /** * @addtogroup platform * @{ */ class CC_DLL CCEGLViewProtocol { protected: EGLTouchDelegate* m_pDelegate; /** real screen size，win32下是窗口的大小， 可以认为这是实际像素尺寸的大小 */ CCSize m_obScreenSize; /** resolution size, 就win32平台上screenSize的单位为像素，这个resolutionSize就是一个虚拟的逻辑上的像素大小了 这样经过缩放就可以按照比例显示在不同分辨率的设备上了，对应于win32的窗口而言，只要分辨率相等， 对应于不同大小的窗口（相当于不同分辨率的设备），图形都会按照比例显示在窗口之上的。 */ CCSize m_obDesignResolutionSize; /** 显示全屏时的显示策略：解释直接查看2dx的官方解释即可，已经很详细了 */ ResolutionPolicy m_eResolutionPolicy; /** 依据分辨率的策略调整的m_obDesignResolutionSize的正确缩放比例 */ float m_fScaleX; float m_fScaleY; /** opengl Screen map 到的窗口矩形,该矩形取决于 以上5个属性，它保存全屏时的screenMap区域 */ CCRect m_obViewPortRect; // the view name，win32下ta是游戏窗口的标题 char m_szViewName[50]; public: CCEGLViewProtocol(); virtual ~CCEGLViewProtocol(); /** 设置Frame的大小（有个疑问，对于移动设备来说这个大小应该是固定的， 当 调用setFrameSize它的宽高参数应该是固定的吧？） 此函数会将resolutionSize也设置成一样大 */ virtual void setFrameSize(float width, float height); virtual const CCSize& getFrameSize() const; /** 设置逻辑分辨率，并根据ResolutionPolicy来正确调整缩放比例与逻辑宽高长度 */ virtual void setDesignResolutionSize(float width, float height, ResolutionPolicy resolutionPolicy); virtual const CCSize& getDesignResolutionSize() const; virtual CCSize getVisibleSize() const; virtual CCPoint getVisibleOrigin() const; virtual void setViewPortInPoints(float x , float y , float w , float h); const CCRect& getViewPortRect() const; float getScaleX() const; float getScaleY() const; virtual void setViewName(const char* pszViewName); const char* getViewName(); //剪切测试 virtual void setScissorInPoints(float x , float y , float w , float h); virtual bool isScissorEnabled(); virtual CCRect getScissorRect(); //其他 /** Force destroying EGL view, subclass must implement this method. */ virtual void end() = 0; /** Get whether opengl render system is ready, subclass must implement this method. */ virtual bool isOpenGLReady() = 0; /** Exchanges the front and back buffers, subclass must implement this method. */ virtual void swapBuffers() = 0; /** Open or close IME keyboard , subclass must implement this method. */ virtual void setIMEKeyboardState(bool bOpen) = 0; /** Set touch delegate */ virtual void setTouchDelegate(EGLTouchDelegate * pDelegate); /** Touch events are handled by default; if you want to customize your handlers, please override these functions: */ /*处理touch事件通知给m_pDelegate*/ virtual void handleTouchesBegin(int num, int ids[], float xs[], float ys[]); virtual void handleTouchesMove(int num, int ids[], float xs[], float ys[]); virtual void handleTouchesEnd(int num, int ids[], float xs[], float ys[]); virtual void handleTouchesCancel(int num, int ids[], float xs[], float ys[]); private: void getSetOfTouchesEndOrCancel(CCSet& set, int num, int ids[], float xs[], float ys[]); };

里面的最重要的函数：

void CCEGLViewProtocol::setDesignResolutionSize(float width, float height, ResolutionPolicy resolutionPolicy) { CCAssert(resolutionPolicy != kResolutionUnKnown, "should set resolutionPolicy"); if (width == 0.0f || height == 0.0f) { return; } m_obDesignResolutionSize.setSize(width, height); //scale 是实际屏幕像素长度与逻辑坐标的长度之比， //如果是kResolutionExactFit模式则直接输出， //如果如果逻辑像素宽高比例和屏幕分辨率比例不等，有可能拉伸会影响显示的效果 m_fScaleX = (float)m_obScreenSize.width / m_obDesignResolutionSize.width; m_fScaleY = (float)m_obScreenSize.height / m_obDesignResolutionSize.height; //kResolutionNoBorder： 长宽按照最大比例进行缩放 //如果逻辑像素宽高比例和屏幕分辨率比例不等，会有部分超出屏幕显示范围 if (resolutionPolicy == kResolutionNoBorder) { m_fScaleX = m_fScaleY = MAX(m_fScaleX, m_fScaleY); } //kResolutionShowAll： 长宽按照最小比例进行缩放，能够确保按照正确的缩放比例显示整个可视区域 //如果如果逻辑像素宽高比例和屏幕分辨率比例不等，会出现部分没有用于显示的黑色区域 if (resolutionPolicy == kResolutionShowAll) { m_fScaleX = m_fScaleY = MIN(m_fScaleX, m_fScaleY); } //按照高度缩放比例进行缩放 if ( resolutionPolicy == kResolutionFixedHeight) { m_fScaleX = m_fScaleY; m_obDesignResolutionSize.width = ceilf(m_obScreenSize.width/m_fScaleX); } //按照宽度缩放比例进行缩放 if ( resolutionPolicy == kResolutionFixedWidth) { m_fScaleY = m_fScaleX; m_obDesignResolutionSize.height = ceilf(m_obScreenSize.height/m_fScaleY); } //计算viewPort,使之执行正确的 screenMap float viewPortW = m_obDesignResolutionSize.width * m_fScaleX; float viewPortH = m_obDesignResolutionSize.height * m_fScaleY; m_obViewPortRect.setRect((m_obScreenSize.width - viewPortW) / 2, (m_obScreenSize.height - viewPortH) / 2, viewPortW, viewPortH); m_eResolutionPolicy = resolutionPolicy; //我认为这种布局让eglview 与director的耦合度很高，使之可读性非常差 // reset director's member variables to fit visible rect CCDirector::sharedDirector()->m_obWinSizeInPoints = getDesignResolutionSize(); //将winSize进行更新操作 CCDirector::sharedDirector()->createStatsLabel(); //依据分辨率重新设置左下角的label CCDirector::sharedDirector()->setGLDefaultValues(); //此函数重新设置投影矩阵 }

进行相关设置后director会重新设置投影矩阵：

void CCDirector::setProjection(ccDirectorProjection kProjection) { //逻辑分辨率 CCSize size = m_obWinSizeInPoints; //在设置projection之前先设置viewPort //注：eglView只会在程序初始化阶段调用初始化opengl的相关函数， //对其他opengl属性设置是在director里面执行或者外部认为调用的 setViewport(); //注：正交、透视投影，view Matrix Transform(我忘了这个怎么翻译中文了)的生成推倒过程可以参看 //<<mathematics for="" 3d="" game="" programming="" and="" computer="" graphics="" 3rd="" edition="">>chapter 3、4，里面讲的很详细 switch (kProjection) { case kCCDirectorProjection2D: { kmGLMatrixMode(KM_GL_PROJECTION); kmGLLoadIdentity(); kmMat4 orthoMatrix; //根据逻辑分辨率的宽高生成正交投影（在宽高之外的坐标的东西将被opengl剪切掉） kmMat4OrthographicProjection(&orthoMatrix, 0, size.width, 0, size.height, -1024, 1024 ); kmGLMultMatrix(&orthoMatrix); kmGLMatrixMode(KM_GL_MODELVIEW); //设置modelview matrix为单位矩阵 kmGLLoadIdentity(); } break; case kCCDirectorProjection3D: { float zeye = this->getZEye(); kmMat4 matrixPerspective, matrixLookup; kmGLMatrixMode(KM_GL_PROJECTION); kmGLLoadIdentity(); //生成透视投影矩阵fov:60, aspect为逻辑分辨率的比例， //frustum 远处截断为m_obWinSizeInPoints.height / 1.1566f*2， //设置这个值是为了根据3d投影摄像机的位置恰好看到坐标范围为：m_obWinSizeInPoints范围内的物体 // issue #1334 kmMat4PerspectiveProjection( &matrixPerspective, 60, (GLfloat)size.width/size.height, 0.1f, zeye*2); // kmMat4PerspectiveProjection( &matrixPerspective, 60, (GLfloat)size.width/size.height, 0.1f, 1500); kmGLMultMatrix(&matrixPerspective); kmGLMatrixMode(KM_GL_MODELVIEW); //加载view matrix kmGLLoadIdentity(); kmVec3 eye, center, up;//opengl是左手坐标系，Z越大越在前面 kmVec3Fill( &eye, size.width/2, size.height/2, zeye ); //camera 位置 kmVec3Fill( ¢er, size.width/2, size.height/2, 0.0f ); //camera 朝向点 kmVec3Fill( &up, 0.0f, 1.0f, 0.0f); //camera 上方位置 kmMat4LookAt(&matrixLookup, &eye, ¢er, &up); kmGLMultMatrix(&matrixLookup); } break; case kCCDirectorProjectionCustom: if (m_pProjectionDelegate) { m_pProjectionDelegate->updateProjection(); } break; default: CCLOG("cocos2d: Director: unrecognized projection"); break; } m_eProjection = kProjection; ccSetProjectionMatrixDirty(); }</mathematics>

在设置投影矩阵前它先设置了screen map的viewPort:

void CCDirector::setViewport() { if (m_pobOpenGLView) { //直接调用glView依据逻辑分辨率来设置视区的范围 m_pobOpenGLView->setViewPortInPoints(0, 0, m_obWinSizeInPoints.width, m_obWinSizeInPoints.height); } } void CCEGLView::setViewPortInPoints(float x , float y , float w , float h) { //这里使用了m_fFrameZoomFactor，来适应frame的缩放 glViewport((GLint)(x * m_fScaleX * m_fFrameZoomFactor + m_obViewPortRect.origin.x * m_fFrameZoomFactor), (GLint)(y * m_fScaleY * m_fFrameZoomFactor + m_obViewPortRect.origin.y * m_fFrameZoomFactor), (GLsizei)(w * m_fScaleX * m_fFrameZoomFactor), (GLsizei)(h * m_fScaleY * m_fFrameZoomFactor)); }

至于director的m_fContentScaleFactor，查看代码它只设置完属性后将坐下脚的label进行了相关的处理而且其他模块也没有用到该属性值，所以就无视他吧~~~

给出他的代码：

void CCDirector::setContentScaleFactor(float scaleFactor) { if (scaleFactor != m_fContentScaleFactor) { m_fContentScaleFactor = scaleFactor; createStatsLabel(); } }

先写到这，分析代码的东西都分析完毕，以后有时间贴几个测试的结果上去，感谢看完这篇文章的淫~~~

有错误欢迎之处哈！