没事就总结了下图片变灰功能，这里提供了2种方式：
第一种：
这种方式是最普遍的，就是直接修改图片的rgb值实现的，这种方式有个弊端，就是需要变灰的精灵必须是Sprite类型才可以，代码如下
void HelloWorld::spriteToGrey(Sprite* sprite_chess)
{
Point point = sprite_chess->getPosition();
sprite_chess->setPosition(sprite_chess->getContentSize().width / 2, sprite_chess->getContentSize().height / 2);
RenderTexture *render = RenderTexture::create(sprite_chess->getContentSize().width, sprite_chess->getContentSize().height, Texture2D::PixelFormat::RGBA8888);
render->beginWithClear(0.0f, 0.0f, 0.0f, 0.0f);
sprite_chess->visit();
render->end();
Director::getInstance()->getRenderer()->render();
Image *finalImage = render->newImage();
unsigned char *pData = finalImage->getData();
int iIndex = 0;
for (int i = 0; i < finalImage->getHeight(); i++)
{
for (int j = 0; j < finalImage->getWidth(); j++)
{
// gray
int iBPos = iIndex;
unsigned int iB = pData;
iIndex++;
unsigned int iG = pData;
iIndex++;
unsigned int iR = pData;
iIndex++;
iIndex++;
unsigned int iGray = 0.3 * iR + 0.6 * iG + 0.1 * iB;
pData = pData = pData = (unsigned char)iGray;
}
}
Texture2D *texture = new Texture2D;
texture->initWithImage(finalImage);
delete finalImage;
sprite_chess->setTexture(texture);
texture->release();
sprite_chess->setPosition(point);
}
第二种：
这种方式是通过shader实现变灰的，功能非常强大，支持Sprite和ImageView类型的图片变灰，已测试无任何问题(变灰后图片位置也不会偏移)，代码如下：
//实现Sprite或者ImageView类型的图片变灰（已修正位置偏移问题）
void HelloWorld::spriteToGrey2(Node* tempSp)
{
ImageView* imgView=dynamic_cast<ImageView*>(tempSp);
Sprite* imgView2=dynamic_cast<Sprite*>(tempSp);
Sprite* sp=nullptr;
if (imgView) {
Scale9Sprite* scale9sp=dynamic_cast<Scale9Sprite*>(imgView->getVirtualRenderer());
if(scale9sp){
sp=scale9sp->getSprite();
}
} else if(imgView2){
sp=imgView2;
}
if (!sp) {
return;
}
const GLchar* pszFragSource =
“#ifdef GL_ES \n
precision mediump float; \n
#endif \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 = v_fragmentColor * texture2D(CC_Texture0, v_texCoord); \n
float grey = dot(col.rgb, vec3(0.299, 0.587, 0.114)); \n
gl_FragColor = vec4(grey, grey, grey, col.a); \n
}”;
GLProgram* pProgram = new GLProgram();
pProgram->initWithByteArrays(ccPositionTextureColor_noMVP_vert, pszFragSource);
sp->setGLProgram(pProgram);
pProgram->release();
CHECK_GL_ERROR_DEBUG();
sp->getGLProgram()->bindAttribLocation(GLProgram::ATTRIBUTE_NAME_POSITION, GLProgram::VERTEX_ATTRIB_POSITION);
sp->getGLProgram()->bindAttribLocation(GLProgram::ATTRIBUTE_NAME_COLOR, GLProgram::VERTEX_ATTRIB_COLOR);
sp->getGLProgram()->bindAttribLocation(GLProgram::ATTRIBUTE_NAME_TEX_COORD, GLProgram::VERTEX_ATTRIB_TEX_COORD);
CHECK_GL_ERROR_DEBUG();
sp->getGLProgram()->link();
CHECK_GL_ERROR_DEBUG();
sp->getGLProgram()->updateUniforms();
CHECK_GL_ERROR_DEBUG();
}
测试环境是：cocos2dx 3.6版本
.强力支持。。。。。。。。。。。
