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, 5 insertions, 9 deletions

diff --git a/source/gameengine/Ketsji/KX_PolyProxy.cpp b/source/gameengine/Ketsji/KX_PolyProxy.cpp
index e102ca4e0e6..c03d585395c 100644
--- a/source/gameengine/Ketsji/KX_PolyProxy.cpp
+++ b/source/gameengine/Ketsji/KX_PolyProxy.cpp
@@ -109,14 +109,12 @@ PyObject* KX_PolyProxy::py_getattro(PyObject *attr)
 		if(polymat->GetFlag() & RAS_BLENDERMAT)
 		{
 			KX_BlenderMaterial* mat = static_cast<KX_BlenderMaterial*>(polymat);
-			Py_INCREF(mat);
-			return mat;
+			return mat->GetProxy();
 		}
 		else
 		{
 			KX_PolygonMaterial* mat = static_cast<KX_PolygonMaterial*>(polymat);
-			Py_INCREF(mat);
-			return mat;
+			return mat->GetProxy();
 		}
 	}
 	if (!strcmp(attr_str, "matid"))
@@ -258,7 +256,7 @@ KX_PYMETHODDEF_DOC_NOARGS(KX_PolyProxy, getMesh,
 "getMesh() : returns a mesh proxy\n")
 {
 	KX_MeshProxy* meshproxy = new KX_MeshProxy((RAS_MeshObject*)m_mesh);
-	return meshproxy;
+	return meshproxy->NewProxy(true);
 }
 
 KX_PYMETHODDEF_DOC_NOARGS(KX_PolyProxy, getMaterial,
@@ -268,13 +266,11 @@ KX_PYMETHODDEF_DOC_NOARGS(KX_PolyProxy, getMaterial,
 	if(polymat->GetFlag() & RAS_BLENDERMAT)
 	{
 		KX_BlenderMaterial* mat = static_cast<KX_BlenderMaterial*>(polymat);
-		Py_INCREF(mat);
-		return mat;
+		return mat->GetProxy();
 	}
 	else
 	{
 		KX_PolygonMaterial* mat = static_cast<KX_PolygonMaterial*>(polymat);
-		Py_INCREF(mat);
-		return mat;
+		return mat->GetProxy();
 	}
 }