BGE Python API

This changes how the BGE classes and Python work together, which hasnt changed since blender went opensource.
The main difference is PyObjectPlus - the base class for most game engine classes, no longer inherit from PyObject, and cannot be cast to a PyObject.

This has the advantage that the BGE does not have to keep 2 reference counts valid for C++ and Python.

Previously C++ classes would never be freed while python held a reference, however this reference could be problematic eg: a GameObject that isnt in a scene anymore should not be used by python, doing so could even crash blender in some cases.

Instead PyObjectPlus has a member "PyObject *m_proxy" which is lazily initialized when python needs it. m_proxy reference counts are managed by python, though it should never be freed while the C++ class exists since it holds a reference to avoid making and freeing it all the time.
When the C++ class is free'd it sets the m_proxy reference to NULL, If python accesses this variable it will raise a RuntimeError, (check the isValid attribute to see if its valid without raising an error).
- This replaces the m_zombie bool and IsZombie() tests added recently.

In python return values that used to be..
 return value->AddRef();
Are now
 return value->GetProxy();
or...
 return value->NewProxy(true); // true means python owns this C++ value which will be deleted when the PyObject is freed

1 files changed, 2 insertions, 2 deletions

diff --git a/source/gameengine/Ketsji/KX_TrackToActuator.cpp b/source/gameengine/Ketsji/KX_TrackToActuator.cpp
index 29c6a21b0b3..5ea08f855a3 100644
--- a/source/gameengine/Ketsji/KX_TrackToActuator.cpp
+++ b/source/gameengine/Ketsji/KX_TrackToActuator.cpp
@@ -481,7 +481,7 @@ PyObject* KX_TrackToActuator::pyattr_get_object(void *self, const struct KX_PYAT
 	if (!actuator->m_object)	
 		Py_RETURN_NONE;
 	else
-		return actuator->m_object->AddRef();
+		return actuator->m_object->GetProxy();
 }
 
 int KX_TrackToActuator::pyattr_set_object(void *self, const struct KX_PYATTRIBUTE_DEF *attrdef, PyObject *value)
@@ -560,7 +560,7 @@ PyObject* KX_TrackToActuator::PyGetObject(PyObject* self, PyObject* args)
 	if (ret_name_only)
 		return PyString_FromString(m_object->GetName());
 	else
-		return m_object->AddRef();
+		return m_object->GetProxy();
 }