cocos2dx 获取精灵的高亮效果

转自：http://blog.csdn.net/tyxkzzf/article/details/38703883

CCSprite* getHighlightSprite(CCSprite* normalsprite) {

    if ( !normalsprite) {

        return CreateDefaultSprite();

    }

    //CCSprite转成CCimage

    CCPoint p = normalsprite->getAnchorPoint();

    normalsprite->setAnchorPoint(ccp(, ));

    CCRenderTexture *outTexture = CCRenderTexture::create((int)normalsprite->getContentSize().width, (int)normalsprite->getContentSize().height);

    outTexture->begin();

    normalsprite->visit();

    outTexture->end();

    normalsprite->setAnchorPoint(p);

    CCImage* finalImage = outTexture->newCCImage();

    unsigned char *pData = finalImage->getData();

    int iIndex = ;

    for (int i = ; i < finalImage->getHeight(); i ++) {

        for (int j = ; j < finalImage->getWidth(); j ++) {

            // highlight

            int iHightlightPlus = ;

            int iBPos = iIndex;

            unsigned int iB = pData[iIndex];

            iIndex ++;

            unsigned int iG = pData[iIndex];

            iIndex ++;

            unsigned int iR = pData[iIndex];

            iIndex ++;

            //unsigned int o = pData[iIndex];

            iIndex ++;  //原来的示例缺少

            iB = (iB + iHightlightPlus >  ?  : iB + iHightlightPlus);

            iG = (iG + iHightlightPlus >  ?  : iG + iHightlightPlus);

            iR = (iR + iHightlightPlus >  ?  : iR + iHightlightPlus);

            //            iR = (iR < 0 ? 0 : iR);

            //            iG = (iG < 0 ? 0 : iG);

            //            iB = (iB < 0 ? 0 : iB);

            pData[iBPos] = (unsigned char)iB;

            pData[iBPos + ] = (unsigned char)iG;

            pData[iBPos + ] = (unsigned char)iR;

        }

    }

    CCTexture2D *texture = new CCTexture2D;

    texture->initWithImage(finalImage);

    CCSprite* newSprite = CCSprite::createWithTexture(texture);

    delete finalImage;

    texture->release();

    return newSprite;

}

这里有更详细的一片介绍文章《Cocos2dx如何反白高亮CCSprite》点击打开链接

在做游戏时遇到需要使用纯白色高亮精灵的场合，尝试了很多办法没有解决问题，目前有以下几种解法：  最简单当然是切换成和精灵图片一样的另一张纯白图片。 另外就是使用glTexEnvi，具体如下：

重写一个类继承CCSprite， 改写draw 函数，如下代码：

void YourSprite::setHightlight(bool hightlight)

{

    if (m_hightlight != hightlight)

    {

        m_hightlight = hightlight;

        if (m_hightlight)

        {

            ccBlendFunc blendFunc = {GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA};

            setBlendFunc(blendFunc);

        }

        else

        {

            ccBlendFunc blendFunc = {CC_BLEND_SRC, CC_BLEND_DST};

            setBlendFunc(blendFunc);

        }

    }

}

    void     YourSprite::draw()

{

     CCNode::draw();

    CCAssert(! m_bUsesBatchNode, "");

    // Default GL states: GL_TEXTURE_2D, GL_VERTEX_ARRAY, GL_COLOR_ARRAY, GL_TEXTURE_COORD_ARRAY

    // Needed states: GL_TEXTURE_2D, GL_VERTEX_ARRAY, GL_COLOR_ARRAY, GL_TEXTURE_COORD_ARRAY

    // Unneeded states: -

    bool newBlend = m_sBlendFunc.src != CC_BLEND_SRC || m_sBlendFunc.dst != CC_BLEND_DST;

    if (newBlend)

    {

        glBlendFunc(m_sBlendFunc.src, m_sBlendFunc.dst);

    }

#define kQuadSize sizeof(m_sQuad.bl)

    if (m_pobTexture)

    {

        glBindTexture(GL_TEXTURE_2D, m_pobTexture->getName());

    }

    else

    {

        glBindTexture(GL_TEXTURE_2D, );

    }

    if (m_hightlight)

    {

        glActiveTexture( GL_TEXTURE0 );

        //the magic

        glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE);

        glTexEnvi(GL_TEXTURE_ENV, GL_COMBINE_RGB, GL_ADD); //you can change me... GL_REPLACE, GL_SUBSTRACT produce nice effects

        glTexEnvi(GL_TEXTURE_ENV, GL_SRC0_RGB, GL_PREVIOUS); //setColor

        glTexEnvi(GL_TEXTURE_ENV, GL_SRC1_RGB, GL_TEXTURE); //your texture

    }

    long offset = (long)&m_sQuad;

    // vertex

    int diff = offsetof(ccV3F_C4B_T2F, vertices);

    glVertexPointer(, GL_FLOAT, kQuadSize, (void*)(offset + diff));

    // color

    diff = offsetof( ccV3F_C4B_T2F, colors);

    glColorPointer(, GL_UNSIGNED_BYTE, kQuadSize, (void*)(offset + diff));

    // tex coords

    diff = offsetof( ccV3F_C4B_T2F, texCoords);

    glTexCoordPointer(, GL_FLOAT, kQuadSize, (void*)(offset + diff));

    glDrawArrays(GL_TRIANGLE_STRIP, , );

    if( newBlend )

    {

        glBlendFunc(CC_BLEND_SRC, CC_BLEND_DST);

    }

#if CC_SPRITE_DEBUG_DRAW == 1

    // draw bounding box

    CCSize s = m_tContentSize;

    CCPoint vertices[] = {

        ccp(,), ccp(s.width,),

        ccp(s.width,s.height), ccp(,s.height)

    };

    ccDrawPoly(vertices, , true);

#elif CC_SPRITE_DEBUG_DRAW == 2

    // draw texture box

    const CCSize& s = m_obRect.size;

    const CCPoint& offsetPix = getOffsetPositionInPixels();

    CCPoint vertices[] = {

        ccp(offsetPix.x,offsetPix.y), ccp(offsetPix.x+s.width,offsetPix.y),

        ccp(offsetPix.x+s.width,offsetPix.y+s.height), ccp(offsetPix.x,offsetPix.y+s.height)

    };

    ccDrawPoly(vertices, , true);

#endif // CC_SPRITE_DEBUG_DRAW

    if (m_hightlight)

    {

        glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);

    }

}