This module contains several simple classes to be used
within games. There is the main Sprite class and
several Group classes that contain Sprites. The
use of these classes is entirely optional when using
pygame. The classes are fairly lightweight and only
provide a starting place for the code that is common
to most games.
The Sprite class is intended to be used as a base class
for the different types of objects in the game. There is
also a base Group class that simply stores sprites.
A game could create new types of Group classes
that operate on specially customized Sprite instances
they contain.
The basic Group class can draw the Sprites it contains
to a Surface. The Group.draw() method requires that
each Sprite have a Surface.image attribute and a
Surface.rect. The Group.clear() method requires
these same attributes, and can be used to erase
all the Sprites with background. There are also
more advanced Groups: pygame.sprite.RenderUpdates()
and pygame.sprite.OrderedUpdates().
Lastly, this module contains several collision functions.
These help find sprites inside multiple groups that
have intersecting bounding rectangles. To find the
collisions, the Sprites are required to have a
Surface.rect attribute assigned.
The groups are designed for high efficiency in removing
and adding Sprites to them. They also allow cheap
testing to see if a Sprite already exists in a Group.
A given Sprite can exist in any number of groups.
A game could use some groups to control object
rendering, and a completely separate set of groups
to control interaction or player movement. Instead
of adding type attributes or bools to a derived
Sprite class, consider keeping the Sprites inside
organized Groups. This will allow for easier
lookup later in the game.
Sprites and Groups manage their relationships
with the add() and remove() methods. These
methods can accept a single or multiple targets
for membership. The default initializers for these
classes also takes a single or list of targets for
initial membership. It is safe to repeatedly add
and remove the same Sprite from a Group.
While it is possible to design sprite and group
classes that don't derive from the Sprite and
AbstractGroup classes below, it is strongly
recommended that you extend those when
you add a Sprite or Group class.
Sprites are not thread safe. So lock them yourself
if using threads.