cocos2dx 图片置灰与还原

首先看一下封装好的两个函数：

void HelloWorld::setNodeGray(Node* node)
{
    if (node)
    {
        GLProgram* p = new GLProgram();
        p->initWithFilenames("gray.vsh", "gray.fsh");
        p->bindAttribLocation(GLProgram::ATTRIBUTE_NAME_POSITION, GLProgram::VERTEX_ATTRIB_POSITION);
        p->bindAttribLocation(GLProgram::ATTRIBUTE_NAME_COLOR, GLProgram::VERTEX_ATTRIB_COLOR);
        p->bindAttribLocation(GLProgram::ATTRIBUTE_NAME_TEX_COORD, GLProgram::VERTEX_ATTRIB_TEX_COORDS);
        p->link();
        p->updateUniforms();
        node->setGLProgram(p);
    }
}

void HelloWorld::removeNodeGray(Node* node)
{
    if (node)
    {
        std::string str = "ShaderPositionTextureColor_noMVP";
        GLProgram * pProgram = ShaderCache::getInstance()->getGLProgram(str);
        node->setShaderProgram(pProgram);
        CHECK_GL_ERROR_DEBUG();
    }
}

那 gray.vsh 和 gray.fsh 又是什么呢？

新建一个文本文件 命名为 gray 并保存为 .vsh 类型，其内容如下：

attribute vec4 a_position;
attribute vec2 a_texCoord;
attribute vec4 a_color;
                     
varying vec4 v_fragmentColor;
varying vec2 v_texCoord;
                                 
void main() 
{                           
    gl_Position = CC_PMatrix * a_position;
    v_fragmentColor = a_color;
    v_texCoord = a_texCoord;
}

再次新建一个文本文件命名为 gray 并保存为 .fsh类型，其内容如下：

varying vec4 v_fragmentColor;   
varying vec2 v_texCoord;    
         
void main()         
{
    vec4 v_orColor = v_fragmentColor * texture2D(CC_Texture0, v_texCoord);
    float gray = dot(v_orColor.rgb, vec3(0.299, 0.587, 0.114));
    gl_FragColor = vec4(gray, gray, gray, v_orColor.a);
}

运行效果如下：