The command SetMobility takes
- the namespace EComponentMobility
- enum called Type
- InMobility is the variable name of the passed enum
if default values work in this case it would be:
in light.h
void SetMobility(EComponentMobility::Type InMobility = EComponentMobility::Type::Movable);
Though if you are only learning c++ then I would advise at least making a backup of the header before any changes.