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, 35 insertions, 9 deletions

diff --git a/source/gameengine/Ketsji/KX_SceneActuator.cpp b/source/gameengine/Ketsji/KX_SceneActuator.cpp
index 2d3022a68f7..b52cc81f68b 100644
--- a/source/gameengine/Ketsji/KX_SceneActuator.cpp
+++ b/source/gameengine/Ketsji/KX_SceneActuator.cpp
@@ -291,23 +291,39 @@ PyObject* KX_SceneActuator::pyattr_get_camera(void *self, const struct KX_PYATTR
 	KX_SceneActuator* actuator = static_cast<KX_SceneActuator*>(self);
 	if (!actuator->m_camera)
 		Py_RETURN_NONE;
-	actuator->m_camera->AddRef();
-	return actuator->m_camera;
+	
+	return actuator->m_camera->GetProxy();
 }
 
 int KX_SceneActuator::pyattr_set_camera(void *self, const struct KX_PYATTRIBUTE_DEF *attrdef, PyObject *value)
 {
 	KX_SceneActuator* actuator = static_cast<KX_SceneActuator*>(self);
 	KX_Camera *camOb;
-
+	
+	if(value==Py_None)
+	{
+		if (actuator->m_camera)
+			actuator->m_camera->UnregisterActuator(actuator);
+		
+		actuator->m_camera= NULL;
+		return 0;
+	}
+	
 	if (PyObject_TypeCheck(value, &KX_Camera::Type)) 
 	{
-		camOb = static_cast<KX_Camera*>(value);
+		KX_Camera *camOb= static_cast<KX_Camera*>BGE_PROXY_REF(value);
+		
+		if(camOb==NULL)
+		{
+			PyErr_SetString(PyExc_RuntimeError, BGE_PROXY_ERROR_MSG);
+			return 1;
+		}
+		
 		if (actuator->m_camera)
 			actuator->m_camera->UnregisterActuator(actuator);
+		
 		actuator->m_camera = camOb;
-		if (actuator->m_camera)
-			actuator->m_camera->RegisterActuator(actuator);
+		actuator->m_camera->RegisterActuator(actuator);
 		return 0;
 	}
 
@@ -423,11 +439,21 @@ PyObject* KX_SceneActuator::PySetCamera(PyObject* self,
 	PyObject *cam;
 	if (PyArg_ParseTuple(args, "O!:setCamera", &KX_Camera::Type, &cam))
 	{
+		KX_Camera *new_camera;
+		
+		new_camera = static_cast<KX_Camera*>BGE_PROXY_REF(cam);
+		if(new_camera==NULL)
+		{
+			PyErr_SetString(PyExc_RuntimeError, BGE_PROXY_ERROR_MSG);
+			return NULL;
+		}
+		
 		if (m_camera)
 			m_camera->UnregisterActuator(this);
-		m_camera = (KX_Camera*) cam;
-		if (m_camera)
-			m_camera->RegisterActuator(this);
+		
+		m_camera= new_camera;
+		
+		m_camera->RegisterActuator(this);
 		Py_RETURN_NONE;
 	}
 	PyErr_Clear();