BGE patch: Relink actuators with target within group when duplicating group; generalize protection against object deletion for all actuators that point to objects.

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.

1 files changed, 27 insertions, 6 deletions

diff --git a/source/gameengine/GameLogic/SCA_PropertyActuator.cpp b/source/gameengine/GameLogic/SCA_PropertyActuator.cpp
index ebe1cd51863..7062f2cef6a 100644
--- a/source/gameengine/GameLogic/SCA_PropertyActuator.cpp
+++ b/source/gameengine/GameLogic/SCA_PropertyActuator.cpp
@@ -42,7 +42,7 @@
 /* Native functions                                                          */
 /* ------------------------------------------------------------------------- */
 
-SCA_PropertyActuator::SCA_PropertyActuator(SCA_IObject* gameobj,CValue* sourceObj,const STR_String& propname,const STR_String& expr,int acttype,PyTypeObject* T )
+SCA_PropertyActuator::SCA_PropertyActuator(SCA_IObject* gameobj,SCA_IObject* sourceObj,const STR_String& propname,const STR_String& expr,int acttype,PyTypeObject* T )
    :	SCA_IActuator(gameobj,T),
 	m_type(acttype),
 	m_propname(propname),
@@ -51,14 +51,14 @@ SCA_PropertyActuator::SCA_PropertyActuator(SCA_IObject* gameobj,CValue* sourceOb
 {
 	// protect ourselves against someone else deleting the source object
 	// don't protect against ourselves: it would create a dead lock
-	if (m_sourceObj && m_sourceObj != GetParent())
-		m_sourceObj->AddRef();
+	if (m_sourceObj)
+		m_sourceObj->RegisterActuator(this);
 }
 
 SCA_PropertyActuator::~SCA_PropertyActuator()
 {
-	if (m_sourceObj && m_sourceObj != GetParent())
-		m_sourceObj->Release();
+	if (m_sourceObj)
+		m_sourceObj->UnregisterActuator(this);
 }
 
 bool SCA_PropertyActuator::Update()
@@ -185,10 +185,31 @@ void SCA_PropertyActuator::ProcessReplica()
 	// no need to check for self reference like in the constructor:
 	// the replica will always have a different parent
 	if (m_sourceObj)
-		m_sourceObj->AddRef();
+		m_sourceObj->RegisterActuator(this);
 	SCA_IActuator::ProcessReplica();
 }
 
+bool SCA_PropertyActuator::UnlinkObject(SCA_IObject* clientobj)
+{
+	if (clientobj == m_sourceObj)
+	{
+		// this object is being deleted, we cannot continue to track it.
+		m_sourceObj = NULL;
+		return true;
+	}
+	return false;
+}
+
+void SCA_PropertyActuator::Relink(GEN_Map<GEN_HashedPtr, void*> *obj_map)
+{
+	void **h_obj = (*obj_map)[m_sourceObj];
+	if (h_obj) {
+		if (m_sourceObj)
+			m_sourceObj->UnregisterActuator(this);
+		m_sourceObj = (SCA_IObject*)(*h_obj);
+		m_sourceObj->RegisterActuator(this);
+	}
+}
 
 
 /* ------------------------------------------------------------------------- */