彩色图转灰度图算法 cocos2dx实现

备忘一下.

//得到灰度CCSprite, int l_iGrayValue = (int)(l_iR*0.299 + l_iG*0.587 + l_iB*0.114);

CCSprite* Tools::getGraySpriteWithFile(const char* p_file){

CCSprite* l_sprite = Tools::getSpriteWithFile(p_file);

CCSize l_sizeInPixel = l_sprite->getContentSizeInPixels();

//开辟出内存buffer

unsigned char* l_buffer = (unsigned char*)malloc(l_sizeInPixel.width * l_sizeInPixel.height * 4);

memset(l_buffer, 0, l_sizeInPixel.width * l_sizeInPixel.height * 4);

//写内存

CCRenderTexture* l_renderTexture = CCRenderTexture::renderTextureWithWidthAndHeight(l_sizeInPixel.width, l_sizeInPixel.height, kCCTexture2DPixelFormat_RGBA8888);

l_renderTexture->begin();

l_sprite->draw();

glReadPixels(0, 0, l_sizeInPixel.width, l_sizeInPixel.height, GL_RGBA, GL_UNSIGNED_BYTE, l_buffer);

l_renderTexture->end();

//变成灰度内存

for (int i=0; i<l_sizeInPixel.height; i++) {

for (int j=0; j<l_sizeInPixel.width; j++) {

CCPoint l_pointInPixel = ccp(j, i);

//l_buffer[4*(int)(l_pointInPixel.y*l_sizeInPixel.width + l_pointInPixel.x)+3] = 0;

int l_iR = l_buffer[4*(int)(l_pointInPixel.y*l_sizeInPixel.width + l_pointInPixel.x)+0];

int l_iG = l_buffer[4*(int)(l_pointInPixel.y*l_sizeInPixel.width + l_pointInPixel.x)+1];

int l_iB = l_buffer[4*(int)(l_pointInPixel.y*l_sizeInPixel.width + l_pointInPixel.x)+2];

int l_iGrayValue = (int)(l_iR*0.299 + l_iG*0.587 + l_iB*0.114);

l_buffer[4*(int)(l_pointInPixel.y*l_sizeInPixel.width + l_pointInPixel.x)+0] = l_iGrayValue;

l_buffer[4*(int)(l_pointInPixel.y*l_sizeInPixel.width + l_pointInPixel.x)+1] = l_iGrayValue;

l_buffer[4*(int)(l_pointInPixel.y*l_sizeInPixel.width + l_pointInPixel.x)+2] = l_iGrayValue;

}

}

//生成灰度CCSprite

CCTexture2D* l_texture = new CCTexture2D();

l_texture->initWithData(l_buffer, kTexture2DPixelFormat_RGBA8888, l_sizeInPixel.width, l_sizeInPixel.height,CCSizeMake(l_sizeInPixel.width, l_sizeInPixel.height));

l_texture->autorelease();

CCSprite* l_spriteGray = CCSprite::spriteWithTexture(l_texture);

//释放临时内存

free(l_buffer);

return l_spriteGray;

}

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