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, 4 insertions, 4 deletions

diff --git a/source/gameengine/Ketsji/KX_TouchSensor.cpp b/source/gameengine/Ketsji/KX_TouchSensor.cpp
index 70fa6326c19..7265ade6789 100644
--- a/source/gameengine/Ketsji/KX_TouchSensor.cpp
+++ b/source/gameengine/Ketsji/KX_TouchSensor.cpp
@@ -342,7 +342,7 @@ PyObject* KX_TouchSensor::PyGetHitObject(PyObject* self)
 	/* otherwise, this leaks memory */
 	if (m_hitObject)
 	{
-		return m_hitObject->AddRef();
+		return m_hitObject->GetProxy();
 	}
 	Py_RETURN_NONE;
 }
@@ -356,7 +356,7 @@ PyObject* KX_TouchSensor::PyGetHitObjectList(PyObject* self)
 	ShowDeprecationWarning("getHitObjectList()", "the objectHitList property");
 	/* to do: do Py_IncRef if the object is already known in Python */
 	/* otherwise, this leaks memory */ /* Edit, this seems ok and not to leak memory - Campbell */
-	return m_colliders->AddRef();
+	return m_colliders->GetProxy();
 }
 
 /*getTouchMaterial and setTouchMaterial were never added to the api,
@@ -400,7 +400,7 @@ PyObject* KX_TouchSensor::pyattr_get_object_hit(void *self_v, const KX_PYATTRIBU
 	KX_TouchSensor* self= static_cast<KX_TouchSensor*>(self_v);
 	
 	if (self->m_hitObject)
-		return self->m_hitObject->AddRef();
+		return self->m_hitObject->GetProxy();
 	else
 		Py_RETURN_NONE;
 }
@@ -408,7 +408,7 @@ PyObject* KX_TouchSensor::pyattr_get_object_hit(void *self_v, const KX_PYATTRIBU
 PyObject* KX_TouchSensor::pyattr_get_object_hit_list(void *self_v, const KX_PYATTRIBUTE_DEF *attrdef)
 {
 	KX_TouchSensor* self= static_cast<KX_TouchSensor*>(self_v);
-	return self->m_colliders->AddRef();
+	return self->m_colliders->GetProxy();
 }