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,v_orColor.a);
}
注意：p->initWithFilenames("gray.vsh","gray.fsh"); 这里对文件引用的路径，我这里直接放到了 Resources 文件夹下
运行效果如下：
