# Source code for pymunk.space

    __docformat__ = "reStructuredText"

    import weakref
    from weakref import WeakSet
    import platform
    import copy

    from . import _chipmunk_cffi
    cp = _chipmunk_cffi.lib
    ffi = _chipmunk_cffi.ffi

    from .vec2d import Vec2d
    from .body import Body
    from .collision_handler import CollisionHandler
    from .query_info import PointQueryInfo, SegmentQueryInfo, ShapeQueryInfo
    from .shapes import Shape, Circle, Poly, Segment
    from .contact_point_set import ContactPointSet
    from ._pickle import PickleMixin
    from pymunk.constraint import Constraint

    class Space(PickleMixin, object):
        """Spaces are the basic unit of simulation. You add rigid bodies, shapes
        and joints to it and then step them all forward together through time.

        A Space can be copied and pickled. Note that any post step callbacks are
        not copied. Also note that some internal collision cache data is not copied,
        which can make the simulation a bit unstable the first few steps of the
        fresh copy.

        Custom properties set on the space will also be copied/pickled.

        Any collision handlers will also be copied/pickled. Note that depending on
        the pickle protocol used there are some restrictions on what functions can
        be copied/pickled.

        Example::

        >>> import pymunk, pickle
        >>> space = pymunk.Space()
        >>> space2 = space.copy()
        >>> space3 = pickle.loads(pickle.dumps(space))
        """

        _pickle_attrs_init = ['threaded']
        _pickle_attrs_general = ['iterations', 'gravity', 'damping',
            'idle_speed_threshold', 'sleep_time_threshold', 'collision_slop',
            'collision_bias', 'collision_persistence', 'threads']

        def __init__(self, threaded=False):
            """Create a new instance of the Space.

            If you set threaded=True the step function will run in threaded mode
            which might give a speedup. Note that even when you set threaded=True
            you still have to set Space.threads=2 to actually use more than one
            thread.

            Also note that threaded mode is not available on Windows, and setting
            threaded=True has no effect on that platform.
            """

            self.threaded = threaded and platform.system() != 'Windows'
            if self.threaded:
                self._space = ffi.gc(cp.cpHastySpaceNew(), cp.cpHastySpaceFree)
            else:
                self._space = ffi.gc(cp.cpSpaceNew(), cp.cpSpaceFree)

            self._handlers = {} # To prevent the gc to collect the callbacks.

            self._post_step_callbacks = {}
            self._removed_shapes = {}

            self._shapes = {}
            self._bodies = set()
            self._static_body = None
            self._constraints = set()

            self._in_step = False
            self._add_later = set()
            self._remove_later = set()

        def _get_self(self):
            return self

        def _get_shapes(self):
            """A list of all the shapes added to this space

            (includes both static and non-static)
            """
            return list(self._shapes.values())
        shapes = property(_get_shapes,
            doc=_get_shapes.__doc__)

        def _get_bodies(self):
            return list(self._bodies)
        bodies = property(_get_bodies,
            doc="""A list of the bodies added to this space""")

        def _get_constraints(self):
            return list(self._constraints)
        constraints = property(_get_constraints,
            doc="""A list of the constraints added to this space""")

        def _get_static_body(self):
            """A dedicated static body for the space.

            You don't have to use it, but because its memory is managed
            automatically with the space its very convenient.
            """
            if self._static_body == None:
                b = cp.cpSpaceGetStaticBody(self._space)
                self._static_body = Body._init_with_body(b)
                self._static_body._space = self
            return self._static_body
        static_body = property(_get_static_body, doc=_get_static_body.__doc__)

        def _set_iterations(self, value):
            cp.cpSpaceSetIterations(self._space, value)
        def _get_iterations(self):
            return cp.cpSpaceGetIterations(self._space)
        iterations = property(_get_iterations, _set_iterations
            , doc="""Iterations allow you to control the accuracy of the solver.

            Defaults to 10.

            Pymunk uses an iterative solver to figure out the forces between
            objects in the space. What this means is that it builds a big list of
            all of the collisions, joints, and other constraints between the
            bodies and makes several passes over the list considering each one
            individually. The number of passes it makes is the iteration count,
            and each iteration makes the solution more accurate. If you use too
            many iterations, the physics should look nice and solid, but may use
            up too much CPU time. If you use too few iterations, the simulation
            may seem mushy or bouncy when the objects should be solid. Setting
            the number of iterations lets you balance between CPU usage and the
            accuracy of the physics. Pymunk's default of 10 iterations is
            sufficient for most simple games.
            """)

        def _set_gravity(self, gravity_vector):
            cp.cpSpaceSetGravity(self._space, tuple(gravity_vector))
        def _get_gravity(self):
            return Vec2d._fromcffi(cp.cpSpaceGetGravity(self._space))
        gravity = property(_get_gravity, _set_gravity
            , doc="""Global gravity applied to the space.

            Defaults to (0,0). Can be overridden on a per body basis by writing
            custom integration functions.
            """)

        def _set_damping(self, damping):
            cp.cpSpaceSetDamping(self._space, damping)
        def _get_damping(self):
            return cp.cpSpaceGetDamping(self._space)
        damping = property(_get_damping, _set_damping
            , doc="""Amount of simple damping to apply to the space.

            A value of 0.9 means that each body will lose 10% of its velocity per
            second. Defaults to 1. Like gravity, it can be overridden on a per
            body basis.
            """)

        def _set_idle_speed_threshold(self, idle_speed_threshold):
            cp.cpSpaceSetIdleSpeedThreshold(self._space, idle_speed_threshold)
        def _get_idle_speed_threshold(self):
            return cp.cpSpaceGetIdleSpeedThreshold(self._space)
        idle_speed_threshold = property(_get_idle_speed_threshold
            , _set_idle_speed_threshold
            , doc="""Speed threshold for a body to be considered idle.

            The default value of 0 means the space estimates a good threshold
            based on gravity.
            """)

        def _set_sleep_time_threshold(self, sleep_time_threshold):
            cp.cpSpaceSetSleepTimeThreshold(self._space, sleep_time_threshold)
        def _get_sleep_time_threshold(self):
            return cp.cpSpaceGetSleepTimeThreshold(self._space)
        sleep_time_threshold = property(_get_sleep_time_threshold
            , _set_sleep_time_threshold
            , doc="""Time a group of bodies must remain idle in order to fall
            asleep.

            The default value of `inf` disables the sleeping algorithm.
            """)

        def _set_collision_slop(self, collision_slop):
            cp.cpSpaceSetCollisionSlop(self._space, collision_slop)
        def _get_collision_slop(self):
            return cp.cpSpaceGetCollisionSlop(self._space)
        collision_slop = property(_get_collision_slop
            , _set_collision_slop
            , doc="""Amount of overlap between shapes that is allowed.

            To improve stability, set this as high as you can without noticable
            overlapping. It defaults to 0.1.
            """)

        def _set_collision_bias(self, collision_bias):
            cp.cpSpaceSetCollisionBias(self._space, collision_bias)
        def _get_collision_bias(self):
            return cp.cpSpaceGetCollisionBias(self._space)
        collision_bias = property(_get_collision_bias
            , _set_collision_bias
            , doc="""Determines how fast overlapping shapes are pushed apart.

            Pymunk allows fast moving objects to overlap, then fixes the overlap
            over time. Overlapping objects are unavoidable even if swept
            collisions are supported, and this is an efficient and stable way to
            deal with overlapping objects. The bias value controls what
            percentage of overlap remains unfixed after a second and defaults
            to ~0.2%. Valid values are in the range from 0 to 1, but using 0 is
            not recommended for stability reasons. The default value is
            calculated as cpfpow(1.0f - 0.1f, 60.0f) meaning that pymunk attempts
            to correct 10% of error ever 1/60th of a second.

            ..Note::
                Very very few games will need to change this value.
            """)

        def _set_collision_persistence(self, collision_persistence):
            cp.cpSpaceSetCollisionPersistence(self._space, collision_persistence)
        def _get_collision_persistence(self):
            return cp.cpSpaceGetCollisionPersistence(self._space)
        collision_persistence = property(_get_collision_persistence
            , _set_collision_persistence
            , doc="""The number of frames the space keeps collision solutions
            around for.

            Helps prevent jittering contacts from getting worse. This defaults
            to 3.

            ..Note::
                Very very few games will need to change this value.
            """)

        def _get_current_time_step(self):
            return cp.cpSpaceGetCurrentTimeStep(self._space)
        current_time_step = property(_get_current_time_step,
            doc="""Retrieves the current (if you are in a callback from
            Space.step()) or most recent (outside of a Space.step() call)
            timestep.
            """)

        def add(self, *objs):
            """Add one or many shapes, bodies or joints to the space

            Unlike Chipmunk and earlier versions of pymunk its now allowed to add
            objects even from a callback during the simulation step. However, the
            add will not be performed until the end of the step.
            """

            if self._in_step:
                self._add_later.add(objs)
                return

            for o in objs:
                if isinstance(o, Body):
                    self._add_body(o)
                elif isinstance(o, Shape):
                    self._add_shape(o)
                elif isinstance(o, Constraint):
                    self._add_constraint(o)
                else:
                    for oo in o:
                        self.add(oo)

        def remove(self, *objs):
            """Remove one or many shapes, bodies or constraints from the space

            Unlike Chipmunk and earlier versions of Pymunk its now allowed to
            remove objects even from a callback during the simulation step.
            However, the removal will not be performed until the end of the step.

            .. Note::
                When removing objects from the space, make sure you remove any
                other objects that reference it. For instance, when you remove a
                body, remove the joints and shapes attached to it.
            """

            if self._in_step:
                self._remove_later.add(objs)
                return

            for o in objs:
                if isinstance(o, Body):
                    self._remove_body(o)
                elif isinstance(o, Shape):
                    self._remove_shape(o)
                elif isinstance(o, Constraint):
                    self._remove_constraint(o)
                else:
                    for oo in o:
                        self.remove(oo)

        def _add_shape(self, shape):
            """Adds a shape to the space"""
            assert shape._get_shapeid() not in self._shapes, "shape already added to space"
            shape._space = weakref.proxy(self)
            self._shapes[shape._get_shapeid()] = shape
            cp.cpSpaceAddShape(self._space, shape._shape)

        def _add_body(self, body):
            """Adds a body to the space"""
            assert body not in self._bodies, "body already added to space"
            body._space = weakref.proxy(self)
            self._bodies.add(body)
            cp.cpSpaceAddBody(self._space, body._body)

        def _add_constraint(self, constraint):
            """Adds a constraint to the space"""
            assert constraint not in self._constraints, "constraint already added to space"
            self._constraints.add(constraint)
            cp.cpSpaceAddConstraint(self._space, constraint._constraint)

        def _remove_shape(self, shape):
            """Removes a shape from the space"""
            self._removed_shapes[shape._get_shapeid()] = shape
            del self._shapes[shape._get_shapeid()]
            cp.cpSpaceRemoveShape(self._space, shape._shape)
        def _remove_body(self, body):
            """Removes a body from the space"""
            body._space = None
            self._bodies.remove(body)
            cp.cpSpaceRemoveBody(self._space, body._body)
        def _remove_constraint(self, constraint):
            """Removes a constraint from the space"""
            self._constraints.remove(constraint)
            cp.cpSpaceRemoveConstraint(self._space, constraint._constraint)

        def reindex_shape(self, shape):
            """Update the collision detection data for a specific shape in the
            space.
            """
            cp.cpSpaceReindexShape(self._space, shape._shape)

        def reindex_shapes_for_body(self, body):
            """Reindex all the shapes for a certain body."""
            cp.cpSpaceReindexShapesForBody(self._space, body._body)

        def reindex_static(self):
            """Update the collision detection info for the static shapes in the
            space. You only need to call this if you move one of the static shapes.
            """
            cp.cpSpaceReindexStatic(self._space)

        def _get_threads(self):
            if self.threaded:
                return int(cp.cpHastySpaceGetThreads(self._space))
            return 1

        def _set_threads(self, n):
            if self.threaded:
                cp.cpHastySpaceSetThreads(self._space, n)
        threads=property(_get_threads, _set_threads,
            doc="""The number of threads to use for running the step function.

            Only valid on platforms other than Windows and when the Space was
            created with threaded=True. Currently the max limit is 2, setting a
            higher value wont have any effect. The default is 1 regardless if the
            Space was created with threaded=True, to keep determinism in the
            simulation.
            """)

        def step(self, dt):
            """Update the space for the given time step.

            Using a fixed time step is highly recommended. Doing so will increase
            the efficiency of the contact persistence, requiring an order of
            magnitude fewer iterations to resolve the collisions in the usual case.

            It is not the same to call step 10 times with a dt of 0.1 and
            calling it 100 times with a dt of 0.01 even if the end result is
            that the simulation moved forward 100 units. Performing  multiple
            calls with a smaller dt creates a more stable and accurate
            simulation. Therefor it sometimes make sense to have a little for loop
            around the step call, like in this example:

            >>> import pymunk
            >>> s = pymunk.Space()
            >>> steps = 10
            >>> for x in range(steps): # move simulation forward 0.1 seconds:
            ...     s.step(0.1 / steps)

            :param float dt: Time step length
            """

            self._in_step = True
            if self.threaded:
                cp.cpHastySpaceStep(self._space, dt)
            else:
                cp.cpSpaceStep(self._space, dt)
            self._removed_shapes = {}
            self._in_step = False

            for objs in self._add_later:
                self.add(objs)
            self._add_later.clear()

            for objs in self._remove_later:
                self.remove(objs)
            self._remove_later.clear()

            for key in self._post_step_callbacks:
                self._post_step_callbacks[key](self)

            self._post_step_callbacks = {}

        def add_collision_handler(self, collision_type_a, collision_type_b):
            """Return the :py:class:`CollisionHandler` for collisions between
            objects of type collision_type_a and collision_type_b.

            Fill the desired collision callback functions, for details see the
            :py:class:`CollisionHandler` object.

            Whenever shapes with collision types (:py:attr:`Shape.collision_type`)
            a and b collide, this handler will be used to process the collision
            events. When a new collision handler is created, the callbacks will all be
            set to builtin callbacks that perform the default behavior (call the
            wildcard handlers, and accept all collisions).

            :param int collision_type_a: Collision type a
            :param int collision_type_b: Collision type b

            :rtype: :py:class:`CollisionHandler`
            """

            key = (collision_type_a, collision_type_b)
            if key in self._handlers:
                return self._handlers[key]

            h = cp.cpSpaceAddCollisionHandler(self._space, collision_type_a, collision_type_b)
            ch = CollisionHandler(h, self)
            self._handlers[key] = ch
            return ch

        def add_wildcard_collision_handler(self, collision_type_a):
            """Add a wildcard collision handler for given collision type.

            This handler will be used any time an object with this type collides
            with another object, regardless of its type. A good example is a
            projectile that should be destroyed the first time it hits anything.
            There may be a specific collision handler and two wildcard handlers.
            It's up to the specific handler to decide if and when to call the
            wildcard handlers and what to do with their return values. (See
            Arbiter.call_wildcard*())

            When a new wildcard handler is created, the callbacks will all be
            set to builtin callbacks that perform the default behavior. (accept
            all collisions in :py:func:`~CollisionHandler.begin` and
            :py:func:`~CollisionHandler.pre_solve`, or do nothing for
            :py:func:`~CollisionHandler.post_solve` and
            :py:func:`~CollisionHandler.separate`.

            :param int collision_type_a: Collision type
            :rtype: :py:class:`CollisionHandler`
            """

            if collision_type_a in self._handlers:
                return self._handlers[collision_type_a]

            h = cp.cpSpaceAddWildcardHandler(self._space, collision_type_a)
            ch = CollisionHandler(h, self)
            self._handlers[collision_type_a] = ch
            return ch

        def add_default_collision_handler(self):
            """Return a reference to the default collision handler or that is
            used to process all collisions that don't have a more specific
            handler.

            The default behavior for each of the callbacks is to call
            the wildcard handlers, ANDing their return values together if
            applicable.
            """
            if None in self._handlers:
                return self._handlers[None]

            _h = cp.cpSpaceAddDefaultCollisionHandler(self._space)
            h = CollisionHandler(_h, self)
            self._handlers[None] = h
            return h

        def add_post_step_callback(self, callback_function, key, *args, **kwargs):
            """Add a function to be called last in the next simulation step.

            Post step callbacks are registered as a function and an object used as
            a key. You can only register one post step callback per object.

            This function was more useful with earlier versions of pymunk where
            you weren't allowed to use the add and remove methods on the space
            during a simulation step. But this function is still available for
            other uses and to keep backwards compatibility.

            .. Note::
                If you remove a shape from the callback it will trigger the
                collision handler for the 'separate' event if it the shape was
                touching when removed.

            .. Note::
                Post step callbacks are not included in pickle / copy of the space.

            :param callback_function: The callback function
            :type callback_function: `func(space : Space, key, *args, **kwargs)`
            :param Any key:
                This object is used as a key, you can only have one callback
                for a single object. It is passed on to the callback function.
            :param args: Optional parameters passed to the callback
            :param kwargs: Optional keyword parameters passed on to the callback

            :return: True if key was not previously added, False otherwise
            """

            if key in self._post_step_callbacks:
                return False

            def f(x):
                callback_function(self, key, *args, **kwargs)

            self._post_step_callbacks[key] = f
            return True

        def point_query(self, point, max_distance, shape_filter):
            """Query space at point for shapes within the given distance range.

            The filter is applied to the query and follows the same rules as the
            collision detection. If a maxDistance of 0.0 is used, the point must
            lie inside a shape. Negative max_distance is also allowed meaning that
            the point must be a under a certain depth within a shape to be
            considered a match.

            See :py:class:`ShapeFilter` for details about how the shape_filter
            parameter can be used.

            .. Note::
                Sensor shapes are included in the result (In
                :py:meth:`Space.point_query_nearest` they are not)

            :param point: Where to check for collision in the Space
            :type point: :py:class:`~vec2d.Vec2d` or (float,float)
            :param float max_distance: Match only within this distance
            :param ShapeFilter shape_filter: Only pick shapes matching the filter

            :rtype: [:py:class:`PointQueryInfo`]
            """

            self.__query_hits = []

            @ffi.callback("void (*cpSpacePointQueryFunc)"
                "(cpShape *shape, cpVect point, cpFloat distance, cpVect gradient, void *data)")
            def cf(_shape, point, distance, gradient, data):
                # space = ffi.from_handle(data)
                shape = self._get_shape(_shape)
                p = PointQueryInfo(
                    shape,
                    Vec2d._fromcffi(point),
                    distance,
                    Vec2d._fromcffi(gradient))
                self.__query_hits.append(p)

            data = ffi.new_handle(self)
            cp.cpSpacePointQuery(
                self._space, tuple(point), max_distance, shape_filter, cf, data)
            return self.__query_hits

        def _get_shape(self, _shape):
            if not bool(_shape):
                return None

            shapeid = cp.cpShapeGetUserData(_shape)
            #return self._shapes[hashid_private]
            if shapeid in self._shapes:
                shape = self._shapes[shapeid]
            elif shapeid in self._removed_shapes:
                shape = self._removed_shapes[shapeid]
            else:
                shape = None
            return shape

        def point_query_nearest(self, point, max_distance, shape_filter):
            """Query space at point the nearest shape within the given distance
            range.

            The filter is applied to the query and follows the same rules as the
            collision detection. If a maxDistance of 0.0 is used, the point must
            lie inside a shape. Negative max_distance is also allowed meaning that
            the point must be a under a certain depth within a shape to be
            considered a match.

            See :py:class:`ShapeFilter` for details about how the shape_filter
            parameter can be used.

            .. Note::
                Sensor shapes are not included in the result (In
                :py:meth:`Space.point_query` they are)

            :param point: Where to check for collision in the Space
            :type point: :py:class:`~vec2d.Vec2d` or (float,float)
            :param float max_distance: Match only within this distance
            :param ShapeFilter shape_filter: Only pick shapes matching the filter

            :rtype: :py:class:`PointQueryInfo` or None
            """
            info = ffi.new("cpPointQueryInfo *")
            _shape = cp.cpSpacePointQueryNearest(
                self._space,
                tuple(point), max_distance,
                shape_filter, info)

            shape = self._get_shape(_shape)

            if shape != None:
                return PointQueryInfo(
                    shape,
                    Vec2d._fromcffi(info.point),
                    info.distance,
                    Vec2d._fromcffi(info.gradient))
            return None

        def segment_query(self, start, end, radius, shape_filter):
            """Query space along the line segment from start to end with the
            given radius.

            The filter is applied to the query and follows the same rules as the
            collision detection.

            See :py:class:`ShapeFilter` for details about how the shape_filter
            parameter can be used.

            .. Note::
                Sensor shapes are included in the result (In
                :py:meth:`Space.segment_query_first` they are not)

            :param start: Starting point
            :param end: End point
            :param float radius: Radius
            :param ShapeFilter shape_filter: Shape filter

            :rtype: [:py:class:`SegmentQueryInfo`]
            """

            self.__query_hits = []

            @ffi.callback("void (*cpSpaceSegmentQueryFunc)"
                "(cpShape *shape, cpVect point, cpVect normal, cpFloat alpha,"
                " void *data)")
            def cf(_shape, point, normal, alpha, data):
                shape = self._get_shape(_shape)
                p = SegmentQueryInfo(
                    shape, Vec2d._fromcffi(point), Vec2d._fromcffi(normal), alpha)
                self.__query_hits.append(p)

            data = ffi.new_handle(self)
            cp.cpSpaceSegmentQuery(
                self._space,
                tuple(start), tuple(end),
                radius,
                shape_filter, cf,
                data)
            return self.__query_hits

        def segment_query_first(self, start, end, radius, shape_filter):
            """Query space along the line segment from start to end with the
            given radius.

            The filter is applied to the query and follows the same rules as the
            collision detection.

            .. Note::
                Sensor shapes are not included in the result (In
                :py:meth:`Space.segment_query` they are)

            See :py:class:`ShapeFilter` for details about how the shape_filter
            parameter can be used.

            :rtype: :py:class:`SegmentQueryInfo` or None
            """
            info = ffi.new("cpSegmentQueryInfo *")
            _shape = cp.cpSpaceSegmentQueryFirst(
                self._space,
                tuple(start), tuple(end),
                radius, shape_filter,
                info)

            shape = self._get_shape(_shape)
            if shape != None:
                return SegmentQueryInfo(
                    shape,
                    Vec2d._fromcffi(info.point),
                    Vec2d._fromcffi(info.normal),
                    info.alpha)
            return None

        def bb_query(self, bb, shape_filter):
            """Query space to find all shapes near bb.

            The filter is applied to the query and follows the same rules as the
            collision detection.

            .. Note::
                Sensor shapes are included in the result

            :param BB bb: Bounding box
            :param ShapeFilter shape_filter: Shape filter

            :rtype: [:py:class:`Shape`]
            """

            self.__query_hits = []
            @ffi.callback("typedef void (*cpSpaceBBQueryFunc)"
                "(cpShape *shape, void *data)")
            def cf(_shape, data):
                shape = self._get_shape(_shape)
                self.__query_hits.append(shape)

            data = ffi.new_handle(self)
            cp.cpSpaceBBQuery(self._space, bb._bb, shape_filter, cf, data)
            return self.__query_hits

        def shape_query(self, shape):
            """Query a space for any shapes overlapping the given shape

            .. Note::
                Sensor shapes are included in the result

            :param shape: Shape to query with
            :type shape: :py:class:`Circle`, :py:class:`Poly` or :py:class:`Segment`

            :rtype: [:py:class:`ShapeQueryInfo`]
            """

            self.__query_hits = []
            @ffi.callback("typedef void (*cpSpaceShapeQueryFunc)"
                "(cpShape *shape, cpContactPointSet *points, void *data)")
            def cf(_shape, _points, _data):
                shape = self._get_shape(_shape)
                point_set = ContactPointSet._from_cp(_points)
                info = ShapeQueryInfo(shape, point_set)
                self.__query_hits.append(info)

            data = ffi.new_handle(self)
            cp.cpSpaceShapeQuery(self._space, shape._shape, cf, data)

            return self.__query_hits

        def debug_draw(self, options):
            """Debug draw the current state of the space using the supplied drawing
            options.

            If you use a graphics backend that is already supported, such as pygame
            and pyglet, you can use the predefined options in their x_util modules,
            for example :py:class:`pygame_util.DrawOptions`.

            Its also possible to write your own graphics backend, see
            :py:class:`SpaceDebugDrawOptions`.

            If you require any advanced or optimized drawing its probably best to
            not use this funtion for the drawing since its meant for debugging
            and quick scripting.

            :type options: :py:class:`SpaceDebugDrawOptions`
            """
            h = ffi.new_handle(self)
            # we need to hold h until the end of cpSpaceDebugDraw to prevent GC
            options._options.data = h

            with options:
                cp.cpSpaceDebugDraw(self._space, options._options)

        def __getstate__(self):
            """Return the state of this object

            This method allows the usage of the :mod:`copy` and :mod:`pickle`
            modules with this class.
            """
            d = super(Space, self).__getstate__()

            d['special'].append(('shapes', self.shapes))
            d['special'].append(('bodies', self.bodies))
            d['special'].append(('constraints', self.constraints))
            if self._static_body != None:
                d['special'].append(('_static_body', self._static_body))

            handlers = []
            for k,v in self._handlers.items():
                h = {}
                if v._begin_base != None:
                    h['_begin_base'] = v._begin_base
                if v._pre_solve_base != None:
                    h['_pre_solve_base'] = v._pre_solve_base
                if v._post_solve_base != None:
                    h['_post_solve_base'] = v._post_solve_base
                if v._separate_base != None:
                    h['_separate_base'] = v._separate_base
                handlers.append((k,h))

            d['special'].append(('_handlers', handlers))

            return d

        def __setstate__(self, state):
            """Unpack this object from a saved state.

            This method allows the usage of the :mod:`copy` and :mod:`pickle`
            modules with this class.
            """
            super(Space, self).__setstate__(state)

            for k,v in state['special']:
                if k == 'shapes':
                    self.add(*v)
                if k == 'bodies':
                    self.add(*v)
                if k == 'constraints':
                    self.add(*v)
                if k == '_static_body':
                    self._static_body = v
                    self._static_body._space = self
                if k == '_handlers':
                    for k, hd in v:
                        if k == None:
                            h = self.add_default_collision_handler()
                        elif isinstance(k,tuple):
                            h = self.add_collision_handler(k[0], k[1])
                        else:
                            h = self.add_wildcard_collision_handler(k)
                        if '_begin_base' in hd:
                            h.begin = hd['_begin_base']
                        if '_pre_solve_base' in hd:
                            h.pre_solve = hd['_pre_solve_base']
                        if '_post_solve_base' in hd:
                            h.post_solve = hd['_post_solve_base']
                        if '_separate_base' in hd:
                            h.separate = hd['_separate_base']

        def copy(self):
            """Create a deep copy of this space."""
            return copy.deepcopy(self)