1. 实现方法：
继承自覆盖和方法实现置灰。
方法和属性声明：


 
 

 	
  
  
是否置灰
 	
  
  
保存置灰的GL程序

 
 
2. shader字符串:
可以像官方那样写在一个.h文件中

3. 核心代码：

 
 

 	
  
  
覆盖父类的和方法，根据调用对应GL程序进行渲染绘制精灵

 
 

4. lua使用示例

 
 

 	
  
  
需手写.pkg文件，使用tolua++工具导出Lua binding文件，在AppDelegate::applicationDidFinishLaunching()注册后，方可在lua层使用 
 
 
 

 
 


查看原文：http://www.51xyyx.com/3195.htmlCCGraySpriteCCSpriteinitWithTexturedrawclass CCGraySprite : public CCSprite{
public:
    CCGraySprite();
    virtual ~CCGraySprite();
    static CCGraySprite* create(const char* pszFileName);
    bool initWithTexture(CCTexture2D* pTexture,const CCRect& tRect);
    static CCGraySprite* createWithSprite(CCSprite *pSprite);
    static CCGraySprite* createWithNodeAndItChild(CCNode *pNode);
    void setGray(bool isGray);
    virtual void draw();

private:
    bool m_isGray;
    CCGLProgram* pProgram;
};m_isGraypProgramGLchar* pszFragSource = (GLchar*)
        "#ifdef GL_ES \n \         precision mediump float; \n \         #endif \n \         uniform sampler2D u_texture; \n \         varying vec2 v_texCoord; \n \         varying vec4 v_fragmentColor; \n \         void main(void) \n \         { \n \         // Convert to greyscale using NTSC weightings \n \         vec4 col = texture2D(u_texture,v_texCoord); \n \         float grey = dot(col.rgb,vec3(0.299,0.587,0.114)); \n \         gl_FragColor = vec4(grey,grey,col.a); \n \         }";initWithTexturedrawm_isGrayvoid CCGraySprite::setGray(bool isGray) {
    m_isGray = isGray;
    if (isGray == true) {
        this->setShaderProgram(pProgram);
    }else
    {
        this->setShaderProgram(CCShaderCache::sharedShaderCache()->programForKey(kCCShader_PositionTextureColor)); } } bool CCGraySprite::initWithTexture(CCTexture2D* pTexture,const CCRect& tRect ){ m_isGray = true; do{ CC_BREAK_IF(!CCSprite::initWithTexture(pTexture,tRect)); GLchar* pszFragSource = (GLchar*) "#ifdef GL_ES \n \ precision mediump float; \n \ #endif \n \ uniform sampler2D u_texture; \n \ varying vec2 v_texCoord; \n \ varying vec4 v_fragmentColor; \n \ void main(void) \n \ { \n \ // Convert to greyscale using NTSC weightings \n \ vec4 col = texture2D(u_texture,v_texCoord); \n \ float grey = dot(col.rgb,vec3(0.299,0.587,0.114)); \n \ gl_FragColor = vec4(grey,col.a); \n \ }"; pProgram = new CCGLProgram(); pProgram->initWithVertexShaderByteArray(ccPositionTextureColor_vert,pszFragSource);
        this->setShaderProgram(pProgram);
        CHECK_GL_ERROR_DEBUG();

        this->getShaderProgram()->addAttribute(kCCAttributeNamePosition,kCCVertexAttrib_Position);
        this->getShaderProgram()->addAttribute(kCCAttributeNameColor,kCCVertexAttrib_Color);
        this->getShaderProgram()->addAttribute(kCCAttributeNameTexCoord,kCCVertexAttrib_TexCoords);
        CHECK_GL_ERROR_DEBUG();

        this->getShaderProgram()->link();
        CHECK_GL_ERROR_DEBUG();

        this->getShaderProgram()->updateUniforms();
        CHECK_GL_ERROR_DEBUG();

        return true;
    } while (0);
    return false;
}

void CCGraySprite::draw(){
    if (this->getTexture() == NULL) {
        return;
    }
    if(m_isGray == false){
        CCSprite::draw();
        return;
    }

    ccGLEnableVertexAttribs(kCCVertexAttribFlag_PosColorTex );
    ccGLBlendFunc( m_sBlendFunc.src,m_sBlendFunc.dst );

    this->getShaderProgram()->use();
    this->getShaderProgram()->setUniformsForBuiltins();

    ccGLBindTexture2D( this->getTexture()->getName() ); #define kQuadSize sizeof(m_sQuad.bl) long offset = (long)&m_sQuad; // vertex int diff = offsetof( ccV3F_C4B_T2F,vertices); glVertexAttribPointer(kCCVertexAttrib_Position,3,GL_FLOAT,GL_FALSE,kQuadSize,(void*) (offset + diff)); // texCoods diff = offsetof( ccV3F_C4B_T2F,texCoords); glVertexAttribPointer(kCCVertexAttrib_TexCoords,2,(void*)(offset + diff)); // color diff = offsetof( ccV3F_C4B_T2F,colors); glVertexAttribPointer(kCCVertexAttrib_Color,4,GL_UNSIGNED_BYTE,GL_TRUE,(void*)(offset + diff)); glDrawArrays(GL_TRIANGLE_STRIP,0,4); CC_INCREMENT_GL_DRAWS(1); }local nameBgSp = CCGraySprite:create("images/namebg.png")local normalSp = CCSprite:create("images/namebg.png")
local graySp = CCGraySprite:createWithNodeAndItChild(normalSp)local frameSp = CCGraySprite:create("images/frame.png")
frameSp:setGray(isGray)