Compton Custom Shader Case 3

gistfile1.glsl

uniform float opacity;
uniform bool invert_color;
uniform sampler2D tex;

        void main() {
            vec4 c = texture2D(tex, gl_TexCoord[0]);
            float eps = 0.004f;
            float eps1 = 1.0f / 255.0f;
            if (invert_color)
                c = vec4(vec3(c.a, c.a, c.a) - vec3(c), c.a);
            if((c.r > 0.2343+eps1-eps && c.r < 0.2343+eps1+eps &&
                c.g > 0.2343+eps1-eps && c.g < 0.2343+eps1+eps &&
                c.b > 0.2343+eps1-eps && c.b < 0.2343+eps1+eps)
               )
            {  }
            else { c *= opacity; }
            gl_FragColor = c;
        }