/// <summary>
/// Unregisters a gravity source, if it exists
/// </summary>
/// <param name="source">A gravity source</param>
public static void Unregister(GravitySource source)
{
Debug.Assert(
_sources.Contains(source),
"Unregistration of unknown gravity source!", source
);
_sources.Remove(source);
}
/// <summary>
/// Registers a new gravity source
/// </summary>
/// <param name="source">A gravity source</param>
public static void Register(GravitySource source)
{
Debug.Assert(
!_sources.Contains(source),
"Duplicate registration of gravity source!", source
);
_sources.Add(source);
}