frag_shader += replace_prefix(effects[i]->output_fragment_shader(), effect_id);
frag_shader += "#undef PREFIX\n";
frag_shader += "#undef FUNCNAME\n";
frag_shader += replace_prefix(effects[i]->output_fragment_shader(), effect_id);
frag_shader += "#undef PREFIX\n";
frag_shader += "#undef FUNCNAME\n";