message: Toggle headlight with 'l' key in viewer
diff: @@ -1173,6 +1173,12 @@ void renderer::on_key_press(key_event const& event)
  show_hud = !show_hud;
  break;
  + case 'l':
  + use_headlight = !use_headlight;
  + counter.reset();
  + clear_frame();
  + break;
  +
  case 'm':
  #ifdef __CUDACC__
  if (rt.mode() == host_device_rt::CPU)
  