Compound shape control
======================
1) GUI control
It is now possible to control which child shape is added to
a parent compound shape in the Physics buttons. The "Compound"
shape button becomes "Add to parent" on child objects and
determines whether the child shape is to be added to the top
parent compound shape when the game is stated.
Notes: * "Compound" is only available to top parent objects
(objects without parent).
* Nesting of compound shape is not possible: a child
object with "Add to parent" button set will be added
to the top parent compound shape, regardless of its
position in the parent-child hierarchy and even if its
immediate parent doesn't have the "Add to parent" button set.
2) runtime control
It is now possible to control the compound shape at runtime:
The SetParent actuator has a new "Compound" button that indicates
whether the object shape should be added to the compound shape
of the parent object, provided the parent has a compound shape
of course. If not, the object retain it's individual state
while parented.
Similarly, the KX_GameObject.setParent() python function has
a new compound parameter.
Notes: * When an object is dynamically added to a compound
shape, it looses temporarily all its physics capability
to the benefit of the parent: it cannot register collisions
and the characteristics of its shape are lost (ghost, sensor,
dynamic, etc.).
* Nested compound shape is not supported: if the object
being parented is already a compound shape, it is not
added to the compound parent (as if the Compound option
was not set in the actuator or the setParent function).
* To ensure compatibility with old blend files, the Blender
subversion is changed to 2.48.5 and the old blend files
are automatically converted to match the old behavior:
all children of a Compound object will have the "Add to
parent" button set automatically.
Child ghost control
===================
It is now possible to control if an object should becomes ghost
or solid when parented. This is only applicable if the object
is not added to the parent compound shape (see above).
A new "Ghost" button is available on the SetParent actuator to
that effect. Similarly the KX_GameObject.setParent() python function
has a new compound parameter.
Notes: * This option is not applicable to sensor objects: they stay
ghost all the time.
* Make sure the child object does not enter in collision with
the parent shape when the Ghost option if off and the parent is
dynamic: the collision creates a reaction force but the parent
cannot escape the child, so the force builds up and produces
eratic movements.
* The collision capability of an ordinary object (dynamic or static)
is limited when it is parented: it becomes automatically static
and can only detect dynamic and sensor objects.
* A sensor object retain its full collision capability when parented:
it can detect static and dynamic object.
Python control
==============
KX_GameObject.setParent(parent,compound,ghost):
Sets this object's parent.
Control the shape status with the optional compound and ghost parameters:
compound=1: the object shape should be added to the parent compound shape (default)
compound=0: the object should keep its individual shape.
In that case you can control if it should be ghost or not:
ghost=1 if the object should be made ghost while parented (default)
ghost=0 if the object should be solid while parented
Note: if the object type is sensor, it stays ghost regardless of ghost parameter
parent: KX_GameObject reference or string (object name w/o OB prefix)
Separate getting a normal attribute and getting __dict__, was having to do too a check for __dict__ on each class (multiple times per getattro call from python) when its not used that often.
- Initialize python types with PyType_Ready, which adds methods to the type dictionary.
- use Pythons get/setattro (uses a python string for the attribute rather then char*). Using basic C strings seems nice but internally python converts them to python strings and discards them for most functions that accept char arrays.
- Method lookups use the PyTypes dictionary (should be faster then Py_FindMethod)
- Renamed __getattr -> py_base_getattro, _getattr -> py_getattro, __repr -> py_base_repr, py_delattro, py_getattro_self etc.
From here is possible to put all the parent classes methods into each python types dictionary to avoid nested lookups (api has 4 levels of lookups in some places), tested this but its not ready yet.
Simple tests for getting a method within a loop show this to be between 0.5 and 3.2x faster then using Py_FindMethod()
Use 'const char *' rather then the C++ 'STR_String' type for the attribute identifier of python attributes.
Each attribute and method access from python was allocating and freeing the string.
A simple test with getting an attribute a loop shows this speeds up attribute lookups a bit over 2x.
* bugfix for BGE python api - SetParent actuator getObject would segfault if the object was not set.
* Added utility function ConvertPythonToGameObject() that can take a GameObject, string or None and set the game object from this since it was being done in a number of places.
* allow setObject(None), since no object is valid for actuators, Python should be able to set this.
* added optional argument for getObject() so it returns the KX_GameObject rather then its name, would prefer this be default but it could break existing games.
Certain actuators hold a pointer to an objects: Property,
SceneCamera, AddObject, Camera, Parent, TractTo. When a
group is duplicated, the actuators that point to objects
within the group will be relinked to point to the
replicated objects and not to the original objects.
This helps to setup self-contained group with a camera
following a character for example.
This feature also works when adding a single object
(and all its children) with the AddObject actuator.
The second part of the patch extends the protection
against object deletion to all the actuators of the above
list (previously, only the TrackTo, AddObject and
Property actuators were protected). In case the target
object of these actuators is deleted, the BGE won't
crash.
This patch consists in new KX_GameObject::SetParent() and KX_GameObject::RemoveParent() functions to create and destroy parent relation during game. These functions are accessible through python and through a new actuator KX_ParentActuator. Function documentation in PyDoc.
The object keeps its orientation, position and scale when it is parented but will further rotate, move and scale with its parent from that point on. When the parent relation is broken, the object keeps the orientation, position and scale it had at that time.
The function has no effect if any of the X/Y/Z scale of the object or its new parent are below Epsilon.
