灰化图片

在res新建2个文件，1个是vsh，1个是fsh

shader_gray.fsh >>>

#ifdef GL_ES

precision mediump float;

#endif

varying vec4 v_fragmentColor;

varying vec2 v_texCoord;

void main()

{

vec4 c = v_fragmentColor * texture2D(CC_Texture0, v_texCoord);

float gray = dot(c.rgb, vec3(0.3, 0.2, 0.2));//灰化的三种颜色值

gl_FragColor = vec4(gray, gray, gray, c.a);

}

shader_gray.vsh >>>

attribute vec4 a_position;

attribute vec2 a_texCoord;

attribute vec4 a_color;

#ifdef GL_ES

varying lowp vec4 v_fragmentColor;

varying mediump vec2 v_texCoord;

#else

varying vec4 v_fragmentColor;

varying vec2 v_texCoord;

#endif

void main()

{

gl_Position = CC_PMatrix * a_position;

v_fragmentColor = a_color;

v_texCoord = a_texCoord;

}

调用方法：

local function getGLProgram()

      return cc.GLProgram:createWithFilenames("shader_gray.vsh", "shader_gray_fsh")

end

local function graySprite（sprite )

      local pProgram = getGLProgram()

      sprite:setGLProgram(pProgram)

end

--清除shader

local function cleanSpriteShader( sprite )

sprite:setGLProgramState(cc.GLProgramState:getOrCreateWithGLProgram(cc.GLProgramCache:getInstance():getGLProgram("ShaderPositionTextureColor_noMVP")));

end

对于cocosStudio的节点，可以再封装下：

local function grayWidget( widget ）

    if string.find(tolua.type(widget), "ccui") then

          local render = widget:getVirtualRenderer()

          if widget:isScale9Enabled() then

                 widget:setCascadeOpacityEnabled(true)--忽略原来的透明度

          end

          local sprite = render:getSprite()

         graySprite(sprite)

    end

end