Constant conrod_glium::FRAGMENT_SHADER_120

pub const FRAGMENT_SHADER_120: &'static str = "
    #version 120
    uniform sampler2D tex;

    varying vec2 v_tex_coords;
    varying vec4 v_color;
    varying float v_mode;

    void main() {
        // Text
        if (v_mode == 0.0) {
            gl_FragColor = v_color * vec4(1.0, 1.0, 1.0, texture2D(tex, v_tex_coords).r);

        // Image
        } else if (v_mode == 1.0) {
            gl_FragColor = texture2D(tex, v_tex_coords);

        // 2D Geometry
        } else if (v_mode == 2.0) {
            gl_FragColor = v_color;
        }
    }
";

The fragment shader used within the glium::Program for OpenGL.