Cocos2dx - CCSprite使用 shader生成自己想要的颜色的图片

class BYGraySprite : public CCSprite{
    
public:
    BYGraySprite();
    virtual ~BYGraySprite();
    static BYGraySprite* create(const char* pszFileName);
    bool initWithTexture(CCTexture2D* pTexture, const CCRect& tRect);
    virtual void draw();
};

#include "BYGraySprite.h"
BYGraySprite::BYGraySprite(){
    
}

BYGraySprite::~BYGraySprite(){
    
}

BYGraySprite* BYGraySprite::create( const char* pszFileName ){
    BYGraySprite* graySprite = new BYGraySprite;
    if (graySprite && graySprite->initWithFile(pszFileName)){
        graySprite->autorelease();
        return graySprite;
    }else{
        CC_SAFE_RELEASE(graySprite);
        return NULL;
    }
}

bool BYGraySprite::initWithTexture(CCTexture2D* pTexture, const CCRect& tRect ){
    do{
        CC_BREAK_IF(!CCSprite::initWithTexture(pTexture, tRect));
        
        GLchar* pszFragSource =
        "#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 \
        float grey = dot(texture2D(u_texture, v_texCoord).rgba, vec4(0.5, 0.0, 0.0,0.7)); \n \
        gl_FragColor = vec4(grey, 0.0, 0.0, 0.0); \n \
        }";
        
        CCGLProgram* pProgram = new CCGLProgram();
        pProgram->initWithVertexShaderByteArray(ccPositionTextureColor_vert, pszFragSource);
        this->setShaderProgram(pProgram);
        pProgram->release();
        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 BYGraySprite::draw(){
    ccGLEnableVertexAttribs(kCCVertexAttribFlag_PosColorTex );
    ccGLBlendFunc( m_sBlendFunc.src, m_sBlendFunc.dst );
    
    this->getShaderProgram()->use();
    this->getShaderProgram()->setUniformForModelViewProjectionMatrix();
    
    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, GL_FLOAT, GL_FALSE, kQuadSize, (void*)(offset + diff));
    
    // color
    diff = offsetof( ccV3F_C4B_T2F, colors);
    glVertexAttribPointer(kCCVertexAttrib_Color, 4, GL_UNSIGNED_BYTE, GL_TRUE, kQuadSize, (void*)(offset + diff));
    glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
    CC_INCREMENT_GL_DRAWS(1);
}

使用

    BYGraySprite* graySprite = BYGraySprite::create("boss.png");
    graySprite->setPosition(ccp(480,320) );
    addChild(graySprite);