Specifies objects which should be drawn at a given location, and which objects should not.
Bag contains, for a given location, all the objects which can be found
at the location. This function places into the bag addToHere
a subset of those objects
which you wish to actually have drawn. The order in which the objects appear in
Bag is the order in which they will be drawn, so the later objects in
the Bag will be drawn on TOP of the earlier objects in the Bag. Do not modify
Bag. The addToHere
bag will be provided to this function in
an empty state; no need to clear() it.
This function should usually return true. However if you wish to use all
the objects in the fromHere Bag, in exactly the order in which they appear,
you can be quite a bit more efficient by not bothering to add the objects into the
addToHere bag and instead simply returning false, in which case the
fromHere bag will be used instead.