uniform sampler2D tex;

uniform vec4 background_color;
uniform mat4 color_transformation;

void main( void ) {
	vec4 orig = texture2D(tex, gl_TexCoord[0].st);


	gl_FragColor = background_color + color_transformation * orig;

	{ // shine
		vec2 offset = vec2(0.01, 0.0);

		vec4 a = texture2D(tex, gl_TexCoord[0].st - offset);
		vec4 b = texture2D(tex, gl_TexCoord[0].st + offset);

		if(length(a-b) < 0.1 && length(orig.rgb) > 0.3)
			gl_FragColor *= 1.0 + 0.01/length(a-b);
	}

	gl_FragColor.a = 1.0;
}