/// <summary>
/// Creates a deep copy of the object, reusing the given object.
/// </summary>
/// <param name="into">The object to copy into.</param>
/// <returns>The copy.</returns>
public IEntityManager DeepCopy(IEntityManager into)
{
var copy = (EntityManager)(into ?? MemberwiseClone());
if (copy == into)
{
// Not a shallow copy, also copy fields.
// Clone the id manager.
copy._idManager = _idManager.DeepCopy(copy._idManager);
// Clone system manager.
copy.SystemManager = SystemManager.DeepCopy(copy.SystemManager);
// Get a list of entities for re-use.
var copyValues = new Stack <Entity>(copy._entityMap.Values);
copy._entityMap.Clear();
// Copy actual entities over.
foreach (var entity in _entityMap.Values)
{
Entity entityCopy;
if (copyValues.Count > 0)
{
entityCopy = copyValues.Pop();
}
else
{
entityCopy = new Entity();
}
copy.AddEntityUnchecked(entity.DeepCopy(entityCopy));
}
}
else
{
// Copy of this instance, create new instances for reference
// types.
// Clone the id manager.
copy._idManager = _idManager.DeepCopy();
// Clone system manager.
copy.SystemManager = SystemManager.DeepCopy();
// Clone all entities.
copy._entityMap = new Dictionary <int, Entity>();
foreach (var entity in _entityMap.Values)
{
copy.AddEntityUnchecked(entity.DeepCopy());
}
}
// Set the entity manager for the clone's system manager.
copy.SystemManager.EntityManager = copy;
return(copy);
}