+// Find what MIDI note the given light (as given by field_number) is mapped to, and enable it.
+void activate_mapped_light(const MIDIMappingBusProto &bus_mapping, int field_number, set<unsigned> *active_lights)
+{
+ const FieldDescriptor *descriptor = bus_mapping.GetDescriptor()->FindFieldByNumber(field_number);
+ const Reflection *bus_reflection = bus_mapping.GetReflection();
+ if (!bus_reflection->HasField(bus_mapping, descriptor)) {
+ return;
+ }
+ const MIDILightProto &light_proto =
+ static_cast<const MIDILightProto &>(bus_reflection->GetMessage(bus_mapping, descriptor));
+ active_lights->insert(light_proto.note_number());
+}
+