For my android application, I want to apply brightness and contrast shader on same image.

At present I am using gpuimage plugin. In that I found two separate program for brightness and contrast as per the following.

Contrast shader:

    varying highp vec2 textureCoordinate;

    uniform sampler2D inputImageTexture;
    uniform lowp float contrast;

    void main()
    {
         lowp vec4 textureColor = texture2D(inputImageTexture, textureCoordinate);

         gl_FragColor = vec4(((textureColor.rgb - vec3(0.5)) * contrast + vec3(0.5)), textureColor.w);
    }

Brightness shader:

    varying highp vec2 textureCoordinate;

    uniform sampler2D inputImageTexture;
    uniform lowp float brightness;

    void main()
    {
        lowp vec4 textureColor = texture2D(inputImageTexture, textureCoordinate);

        gl_FragColor = vec4((textureColor.rgb + vec3(brightness)), textureColor.w);
    }

Now applying both of the effects I write following code

    varying highp vec2 textureCoordinate;
    uniform sampler2D inputImageTexture;
    varying highp vec2 textureCoordinate2;
    uniform sampler2D inputImageTexture2;
    uniform lowp float contrast;
    uniform lowp float brightness;

    void main()
    {
        lowp vec4 textureColorForContrast = texture2D(inputImageTexture, textureCoordinate);

        lowp vec4 contastVec4 = vec4(((textureColorForContrast.rgb - vec3(0.5)) * contrast + vec3(0.5)), textureColorForContrast.w);
        lowp vec4 textureColorForBrightness = texture2D(inputImageTexture2, textureCoordinate2);

        lowp vec4 brightnessVec4 = vec4((textureColorForBrightness.rgb + vec3(brightness)), textureColorForBrightness.w);
        gl_FragColor = contastVec4 + brightnessVec4;
    }

Doesn't able to get desire result. I can't able to figure out what I have to do next? So please friends help me in this. What program I have to write?