/// <summary>
/// Retrieves an ImmutableList<Entity> of all the
/// entities in the Engine matching a Family. This list is
/// automatically updated since its contacts are stored by
/// reference.
/// </summary>
/// <param name="family">Family to match against.</param>
/// <returns>ImmutableList<Entity> of the entities in the Engine.</returns>
public ImmutableList <Entity> GetEntitiesFor(Family family)
{
if (!_familyManagers.ContainsKey(family))
{
FamilyManager familyMap = new FamilyManager(family, this);
familyMap.Initialize();
_familyManagers.Add(family, familyMap);
foreach (Type compType in family._allComponents)
{
if (!_components.ContainsKey(compType))
{
Type componentMapType = typeof(ComponentMap <>).MakeGenericType(compType);
_components.Add(compType, (IComponentMap)Activator.CreateInstance(componentMapType, this));
_components[compType].Initialize();
}
_components[compType].RegisterFamilyManager(familyMap);
}
foreach (Type compType in family._oneComponents)
{
if (!_components.ContainsKey(compType))
{
Type componentMapType = typeof(ComponentMap <>).MakeGenericType(compType);
_components.Add(compType, (IComponentMap)Activator.CreateInstance(componentMapType, this));
_components[compType].Initialize();
}
_components[compType].RegisterFamilyManager(familyMap);
}
foreach (Type compType in family._excludeComponents)
{
if (!_components.ContainsKey(compType))
{
Type componentMapType = typeof(ComponentMap <>).MakeGenericType(compType);
_components.Add(compType, (IComponentMap)Activator.CreateInstance(componentMapType, this));
_components[compType].Initialize();
}
_components[compType].RegisterFamilyManager(familyMap);
}
}
return(_familyManagers[family].FamilyEntities);
}