BGE performance: second round of scenegraph improvement.

Use dynamic linked list to handle scenegraph rather than dumb scan
of the whole tree. The performance improvement depends on the fraction
of moving objects. If most objects are static, the speed up is 
considerable. The following table compares the time spent on 
scenegraph before and after this commit on a scene with 10000 objects
in various configuratons:

Scenegraph time (ms)              Before         After
(includes culling)

All objects static,               8.8            1.7  
all visible but small fraction          
in the view frustrum

All objects static,               7,5            0.01
all invisible.

All objects moving,               14.1           8.4
all visible but small fraction
in the view frustrum

This tables shows that static and invisible objects take no CPU at all
for scenegraph and culling. In the general case, this commit will 
speed up the scenegraph between 2x and 5x. Compared to 2.48a, it should
be between 4x and 10x faster. Further speed up is possible by making
the scenegraph cache-friendly.

Next round of performance improvement will be on the rasterizer: use
the same dynamic linked list technique for the mesh slots.

13 files changed, 649 insertions, 429 deletions

diff --git a/source/gameengine/Converter/BL_BlenderDataConversion.cpp b/source/gameengine/Converter/BL_BlenderDataConversion.cpp
index 6a570c9e815..c4c71d9dd85 100644
--- a/source/gameengine/Converter/BL_BlenderDataConversion.cpp
+++ b/source/gameengine/Converter/BL_BlenderDataConversion.cpp
@@ -2055,7 +2055,7 @@ void BL_ConvertBlenderObjects(struct Main* maggie,
 			if ((blenderobject->parent != 0)&&(!converter->addInitFromFrame))
 			{
 				// blender has an additional 'parentinverse' offset in each object
-				SG_Node* parentinversenode = new SG_Node(NULL,NULL,SG_Callbacks());
+				SG_Node* parentinversenode = new SG_Node(NULL,kxscene,SG_Callbacks(NULL,NULL,NULL,KX_Scene::KX_ScenegraphUpdateFunc,KX_Scene::KX_ScenegraphRescheduleFunc));
 			
 				// define a normal parent relationship for this node.
 				KX_NormalParentRelation * parent_relation = KX_NormalParentRelation::New();
@@ -2249,7 +2249,7 @@ void BL_ConvertBlenderObjects(struct Main* maggie,
 							if ((blenderobject->parent != 0)&&(!converter->addInitFromFrame))
 							{
 								// blender has an additional 'parentinverse' offset in each object
-								SG_Node* parentinversenode = new SG_Node(NULL,NULL,SG_Callbacks());
+								SG_Node* parentinversenode = new SG_Node(NULL,kxscene,SG_Callbacks(NULL,NULL,NULL,KX_Scene::KX_ScenegraphUpdateFunc,KX_Scene::KX_ScenegraphRescheduleFunc));
 							
 								// define a normal parent relationship for this node.
 								KX_NormalParentRelation * parent_relation = KX_NormalParentRelation::New();
diff --git a/source/gameengine/Ketsji/KX_SG_BoneParentNodeRelationship.cpp b/source/gameengine/Ketsji/KX_SG_BoneParentNodeRelationship.cpp
index 0e7571031e8..cb933419c57 100644
--- a/source/gameengine/Ketsji/KX_SG_BoneParentNodeRelationship.cpp
+++ b/source/gameengine/Ketsji/KX_SG_BoneParentNodeRelationship.cpp
@@ -125,7 +125,9 @@ UpdateChildCoordinates(
 	else {
 		child->SetWorldFromLocalTransform();
 	}
-	child->SetModified(false);
+	child->ClearModified();
+	// this node must always be updated, so reschedule it for next time
+	child->ActivateRecheduleUpdateCallback();
 	return valid_parent_transform;
 }
 
diff --git a/source/gameengine/Ketsji/KX_SG_NodeRelationships.cpp b/source/gameengine/Ketsji/KX_SG_NodeRelationships.cpp
index c3b0c21c8e0..c49b6d671a7 100644
--- a/source/gameengine/Ketsji/KX_SG_NodeRelationships.cpp
+++ b/source/gameengine/Ketsji/KX_SG_NodeRelationships.cpp
@@ -63,7 +63,7 @@ UpdateChildCoordinates(
 
 	if (parent==NULL) { /* Simple case */
 		child->SetWorldFromLocalTransform();
-		child->SetModified(false);
+		child->ClearModified();
 		return true; //false;
 	}
 	else {
@@ -75,7 +75,7 @@ UpdateChildCoordinates(
 		child->SetWorldScale(p_world_scale * child->GetLocalScale());
 		child->SetWorldOrientation(p_world_rotation * child->GetLocalOrientation());
 		child->SetWorldPosition(p_world_pos + p_world_scale * (p_world_rotation * child->GetLocalPosition()));
-		child->SetModified(false);
+		child->ClearModified();
 		return true;
 	}
 }
@@ -137,7 +137,7 @@ UpdateChildCoordinates(
 		child->SetWorldPosition(child->GetLocalPosition());
 	
 	child->SetWorldOrientation(child->GetLocalOrientation());
-	child->SetModified(false);
+	child->ClearModified();
 	return true; //parent != NULL;
 }
 
@@ -259,7 +259,9 @@ UpdateChildCoordinates(
 	child->SetWorldScale(child_w_scale);
 	child->SetWorldPosition(child_w_pos);
 	child->SetWorldOrientation(child_w_rotation);
-	child->SetModified(false);
+	child->ClearModified();
+	// this node must always be updated, so reschedule it for next time
+	child->ActivateRecheduleUpdateCallback();
 	
 	return true; //parent != NULL;
 }
diff --git a/source/gameengine/Ketsji/KX_Scene.cpp b/source/gameengine/Ketsji/KX_Scene.cpp
index 171ed5d130f..d31d451f02e 100644
--- a/source/gameengine/Ketsji/KX_Scene.cpp
+++ b/source/gameengine/Ketsji/KX_Scene.cpp
@@ -111,7 +111,22 @@ void* KX_SceneDestructionFunc(SG_IObject* node,void* gameobj,void* scene)
 	return NULL;
 };
 
-SG_Callbacks KX_Scene::m_callbacks = SG_Callbacks(KX_SceneReplicationFunc,KX_SceneDestructionFunc,KX_GameObject::UpdateTransformFunc);
+bool KX_Scene::KX_ScenegraphUpdateFunc(SG_IObject* node,void* gameobj,void* scene)
+{
+	return ((SG_Node*)node)->Schedule(((KX_Scene*)scene)->m_sghead);
+}
+
+bool KX_Scene::KX_ScenegraphRescheduleFunc(SG_IObject* node,void* gameobj,void* scene)
+{
+	return ((SG_Node*)node)->Reschedule(((KX_Scene*)scene)->m_sghead);
+}
+
+SG_Callbacks KX_Scene::m_callbacks = SG_Callbacks(
+	KX_SceneReplicationFunc,
+	KX_SceneDestructionFunc,
+	KX_GameObject::UpdateTransformFunc,
+	KX_Scene::KX_ScenegraphUpdateFunc,
+	KX_Scene::KX_ScenegraphRescheduleFunc);
 
 // temporarily var until there is a button in the userinterface
 // (defined in KX_PythonInit.cpp)
@@ -1473,15 +1488,28 @@ void KX_Scene::LogicEndFrame()
   */
 void KX_Scene::UpdateParents(double curtime)
 {
-//	int numrootobjects = GetRootParentList()->GetCount();
+	// we use the SG dynamic list
+	SG_Node* node;
 
-	for (int i=0; i<GetRootParentList()->GetCount(); i++)
+	while ((node = SG_Node::GetNextScheduled(m_sghead)) != NULL)
 	{
-		KX_GameObject* parentobj = (KX_GameObject*)GetRootParentList()->GetValue(i);
-		parentobj->NodeUpdateGS(curtime);
+		node->UpdateWorldData(curtime);
 	}
-}
 
+	//for (int i=0; i<GetRootParentList()->GetCount(); i++)
+	//{
+	//	KX_GameObject* parentobj = (KX_GameObject*)GetRootParentList()->GetValue(i);
+	//	parentobj->NodeUpdateGS(curtime);
+	//}
+
+	// the list must be empty here
+	assert(m_sghead.Empty());
+	// some nodes may be ready for reschedule, move them to schedule list for next time
+	while ((node = SG_Node::GetNextRescheduled(m_sghead)) != NULL)
+	{
+		node->Schedule(m_sghead);
+	}
+}
 
 
 RAS_MaterialBucket* KX_Scene::FindBucket(class RAS_IPolyMaterial* polymat, bool &bucketCreated)
diff --git a/source/gameengine/Ketsji/KX_Scene.h b/source/gameengine/Ketsji/KX_Scene.h
index 52a3cd5733e..0cfef8b7bd1 100644
--- a/source/gameengine/Ketsji/KX_Scene.h
+++ b/source/gameengine/Ketsji/KX_Scene.h
@@ -118,6 +118,11 @@ protected:
 	CListValue*			m_parentlist; // all 'root' parents
 	CListValue*			m_lightlist;
 	CListValue*			m_inactivelist;	// all objects that are not in the active layer
+	
+	SG_QList			m_sghead;		// list of nodes that needs scenegraph update
+										// the Dlist is not object that must be updated
+										// the Qlist is for objects that needs to be rescheduled
+										// for updates after udpate is over (slow parent, bone parent)
 
 	/**
 	 *  The tree of objects in the scene.
@@ -307,6 +312,8 @@ public:
 	/**
 	 * Update all transforms according to the scenegraph.
 	 */
+	static bool KX_ScenegraphUpdateFunc(SG_IObject* node,void* gameobj,void* scene);
+	static bool KX_ScenegraphRescheduleFunc(SG_IObject* node,void* gameobj,void* scene);
 	void UpdateParents(double curtime);
 	void DupliGroupRecurse(CValue* gameobj, int level);
 	bool IsObjectInGroup(CValue* gameobj)
diff --git a/source/gameengine/SceneGraph/SG_DList.h b/source/gameengine/SceneGraph/SG_DList.h
new file mode 100644
index 00000000000..d682be679e6
--- /dev/null
+++ b/source/gameengine/SceneGraph/SG_DList.h
@@ -0,0 +1,147 @@
+/**
+ * $Id$
+ *
+ * ***** BEGIN GPL LICENSE BLOCK *****
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ *
+ * The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
+ * All rights reserved.
+ *
+ * The Original Code is: all of this file.
+ *
+ * Contributor(s): none yet.
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ */
+#ifndef __SG_DLIST
+#define __SG_DLIST
+
+#include <stdlib.h>
+
+/**
+ * Double circular linked list
+ */
+class SG_DList
+{
+protected :
+	SG_DList* m_flink;
+	SG_DList* m_blink;
+
+public:
+	template<typename T> class iterator
+	{
+	private:
+		SG_DList&	m_head;
+		T*			m_current;
+	public:
+		typedef iterator<T> _myT;
+		iterator(SG_DList& head) : m_head(head), m_current(NULL) {}
+		~iterator() {}
+
+		void begin()
+		{
+			m_current = (T*)m_head.Peek();
+			if (m_current == (T*)m_head.Self())
+			{
+				m_current = NULL;
+			}
+		}
+		bool end()
+		{
+			return (NULL == m_current);
+		}
+		T* operator*()
+		{
+			return m_current;
+		}
+		_myT& operator++()
+		{
+			assert(m_current);
+			m_current = (T*)m_current->Peek();
+			if (m_current == (T*)m_head.Self())
+			{
+				m_current = NULL;
+			}
+			return *this;
+		}
+	};
+
+    SG_DList() 
+    { 
+        m_flink = m_blink = this; 
+    }
+    virtual ~SG_DList() 
+    {
+		Delink();
+    }
+
+    inline bool Empty()               // Check for empty queue
+    {     
+        return ( m_flink == this ); 
+    }
+    bool AddBack( SG_DList *item )  // Add to the back
+    {
+		if (!item->Empty())
+			return false;
+        item->m_blink = m_blink;
+        item->m_flink = this;
+        m_blink->m_flink = item;
+        m_blink = item;
+		return true;
+    }
+    bool AddFront( SG_DList *item )  // Add to the back
+    {
+		if (!item->Empty())
+			return false;
+        item->m_flink = m_flink;
+        item->m_blink = this;
+        m_flink->m_blink = item;
+        m_flink = item;
+		return true;
+    }
+    SG_DList *Remove()           // Remove from the front
+    {
+        if (Empty()) 
+        {
+            return NULL;
+        }
+        SG_DList* item = m_flink;
+        m_flink = item->m_flink;
+        m_flink->m_blink = this;
+        item->m_flink = item->m_blink = item;
+        return item;
+    }
+    void Delink()             // Remove from the middle
+    {
+		if (!Empty())
+		{
+			m_blink->m_flink = m_flink;
+			m_flink->m_blink = m_blink;
+			m_flink = m_blink = this;
+		}
+    }
+    inline SG_DList *Peek()			// Look at front without removing
+    { 
+        return m_flink; 
+    }  
+    inline SG_DList *Self() 
+    { 
+        return this; 
+    }
+};
+
+#endif //__SG_DLIST
+
diff --git a/source/gameengine/SceneGraph/SG_IObject.cpp b/source/gameengine/SceneGraph/SG_IObject.cpp
index fbab4032a10..5795ca57113 100644
--- a/source/gameengine/SceneGraph/SG_IObject.cpp
+++ b/source/gameengine/SceneGraph/SG_IObject.cpp
@@ -39,19 +39,20 @@ SG_IObject::
 SG_IObject(
 	void* clientobj,
 	void* clientinfo,
-	SG_Callbacks callbacks
+	SG_Callbacks& callbacks
 ): 
+	SG_QList(),
 	m_SGclientObject(clientobj),
-	m_SGclientInfo(clientinfo),
-	m_callbacks(callbacks) 
+	m_SGclientInfo(clientinfo)
 {
-	//nothing to do
+	m_callbacks = callbacks;
 }
 
 SG_IObject::
 SG_IObject(
 	const SG_IObject &other
 ) :
+	SG_QList(),
 	m_SGclientObject(other.m_SGclientObject),
 	m_SGclientInfo(other.m_SGclientInfo),
 	m_callbacks(other.m_callbacks) 
@@ -74,92 +75,17 @@ RemoveAllControllers(
 	m_SGcontrollers.clear(); 
 }
 
-/// Needed for replication
-	SGControllerList&	
-SG_IObject::
-GetSGControllerList(
-){ 
-	return m_SGcontrollers; 
-}
-
-	void*				
-SG_IObject::
-GetSGClientObject(
-){ 
-	return m_SGclientObject;
-}
-
-const 
-	void*			
-SG_IObject::
-GetSGClientObject(
-) const	{
-	return m_SGclientObject;
-}
-
-	void	
-SG_IObject::
-SetSGClientObject(
-	void* clientObject
-){
-	m_SGclientObject = clientObject;
-}
-
-
-	bool
-SG_IObject::
-ActivateReplicationCallback(
-	SG_IObject *replica
-){
-	if (m_callbacks.m_replicafunc)
-	{
-		// Call client provided replication func
-		if (m_callbacks.m_replicafunc(replica,m_SGclientObject,m_SGclientInfo) == NULL)
-			return false;
-	}
-	return true;
-};	
-
-	void
-SG_IObject::
-ActivateDestructionCallback(
-){
-	if (m_callbacks.m_destructionfunc)
-	{
-		// Call client provided destruction function on this!
-		m_callbacks.m_destructionfunc(this,m_SGclientObject,m_SGclientInfo);
-	}
-	else
-	{
-		// no callback but must still destroy the node to avoid memory leak
-		delete this;
-	}
-}
-
-	void
-SG_IObject::
-ActivateUpdateTransformCallback(
-){
-	if (m_callbacks.m_updatefunc)
-	{
-		// Call client provided update func.
-		m_callbacks.m_updatefunc(this, m_SGclientObject, m_SGclientInfo);
-	}
-}
-
-	void 
-SG_IObject::
-SetControllerTime(
-	double time
-){
+void SG_IObject::SetControllerTime(double time)
+{
 	SGControllerList::iterator contit;
-
 	for (contit = m_SGcontrollers.begin();contit!=m_SGcontrollers.end();++contit)
 	{
 		(*contit)->SetSimulatedTime(time);
 	}
 }
 
+/// Needed for replication
+
 
 SG_IObject::
 ~SG_IObject()
diff --git a/source/gameengine/SceneGraph/SG_IObject.h b/source/gameengine/SceneGraph/SG_IObject.h
index 9012b532059..b4dd9a9ddf2 100644
--- a/source/gameengine/SceneGraph/SG_IObject.h
+++ b/source/gameengine/SceneGraph/SG_IObject.h
@@ -29,6 +29,7 @@
 #ifndef __SG_IOBJECT
 #define __SG_IOBJECT
 
+#include "SG_QList.h"
 #include <vector>
 
 // used for debugging: stage of the game engine main loop at which a Scenegraph modification is done
@@ -84,6 +85,18 @@ typedef void  (*SG_UpdateTransformCallback)(
 	void*	clientinfo
 );
 
+typedef bool  (*SG_ScheduleUpdateCallback)(
+	SG_IObject* sgobject,
+	void*	clientobj,
+	void*	clientinfo
+);
+
+typedef bool  (*SG_RescheduleUpdateCallback)(
+	SG_IObject* sgobject,
+	void*	clientobj,
+	void*	clientinfo
+);
+
 
 /**
  * SG_Callbacks hold 2 call backs to the outside world.
@@ -106,30 +119,38 @@ struct	SG_Callbacks
 	):
 		m_replicafunc(NULL),
 		m_destructionfunc(NULL),
-		m_updatefunc(NULL)
+		m_updatefunc(NULL),
+		m_schedulefunc(NULL),
+		m_reschedulefunc(NULL)
 	{
 	};
 		
 	SG_Callbacks(
 		SG_ReplicationNewCallback repfunc,
 		SG_DestructionNewCallback destructfunc,
-		SG_UpdateTransformCallback updatefunc
+		SG_UpdateTransformCallback updatefunc,
+		SG_ScheduleUpdateCallback schedulefunc,
+		SG_RescheduleUpdateCallback reschedulefunc
 	): 
 		m_replicafunc(repfunc),
 		m_destructionfunc(destructfunc),
-		m_updatefunc(updatefunc)
+		m_updatefunc(updatefunc),
+		m_schedulefunc(schedulefunc),
+		m_reschedulefunc(reschedulefunc)
 	{
 	};
 
 	SG_ReplicationNewCallback	m_replicafunc;
 	SG_DestructionNewCallback	m_destructionfunc;
 	SG_UpdateTransformCallback	m_updatefunc;
+	SG_ScheduleUpdateCallback	m_schedulefunc;
+	SG_RescheduleUpdateCallback m_reschedulefunc;
 };
 
 /**
 base object that can be part of the scenegraph.
 */
-class SG_IObject
+class SG_IObject : public SG_QList
 {
 private :
 
@@ -177,9 +198,10 @@ public:
 	 * using STL? 
 	 */
 
-		SGControllerList&	
-	GetSGControllerList(
-	);
+	SGControllerList& GetSGControllerList()
+	{ 
+		return m_SGcontrollers; 
+	}
 
 	
 	/**
@@ -192,16 +214,16 @@ public:
 	 * This may be NULL.
 	 */
 
-		void*				
-	GetSGClientObject(
-	);
+	inline const void* GetSGClientObject() const	
+	{
+		return m_SGclientObject;
+	}
 
-	const 
-		void*			
-	GetSGClientObject(
-	) const	;
+	inline void* GetSGClientObject()
+	{ 
+		return m_SGclientObject;
+	}
 
-	
 	/**
 	 * Set the client object for this node. This is just a 
 	 * pointer to an object allocated that should exist for 
@@ -209,10 +231,10 @@ public:
 	 * this function is called again.
 	 */
 	
-		void	
-	SetSGClientObject(
-		void* clientObject
-	);
+	void SetSGClientObject(void* clientObject)
+	{
+		m_SGclientObject = clientObject;
+	}
 
 	/** 
 	 * Set the current simulation time for this node.
@@ -220,10 +242,7 @@ public:
 	 * the nodes list of controllers and calls their SetSimulatedTime methods
 	 */
  
-		void		
-	SetControllerTime(
-		double time
-	);
+	void SetControllerTime(double time);
 	
 	virtual 
 		void		
@@ -235,20 +254,76 @@ protected :
 		bool
 	ActivateReplicationCallback(
 		SG_IObject *replica
-	);
+	)
+	{
+		if (m_callbacks.m_replicafunc)
+		{
+			// Call client provided replication func
+			if (m_callbacks.m_replicafunc(replica,m_SGclientObject,m_SGclientInfo) == NULL)
+				return false;
+		}
+		return true;
+	}
+
 
 		void
 	ActivateDestructionCallback(
-	);
+	)
+	{
+		if (m_callbacks.m_destructionfunc)
+		{
+			// Call client provided destruction function on this!
+			m_callbacks.m_destructionfunc(this,m_SGclientObject,m_SGclientInfo);
+		}
+		else
+		{
+			// no callback but must still destroy the node to avoid memory leak
+			delete this;
+		}
+	}
 	
 		void
 	ActivateUpdateTransformCallback(
-	);
+	)
+	{
+		if (m_callbacks.m_updatefunc)
+		{
+			// Call client provided update func.
+			m_callbacks.m_updatefunc(this, m_SGclientObject, m_SGclientInfo);
+		}
+	}
+
+		bool
+	ActivateScheduleUpdateCallback(
+	)
+	{
+		// HACK, this check assumes that the scheduled nodes are put on a DList (see SG_Node.h)
+		// The early check on Empty() allows up to avoid calling the callback function
+		// when the node is already scheduled for update.
+		if (Empty() && m_callbacks.m_schedulefunc)
+		{
+			// Call client provided update func.
+			return m_callbacks.m_schedulefunc(this, m_SGclientObject, m_SGclientInfo);
+		}
+		return false;
+	}
+
+		void
+	ActivateRecheduleUpdateCallback(
+	)
+	{
+		if (m_callbacks.m_reschedulefunc)
+		{
+			// Call client provided update func.
+			m_callbacks.m_reschedulefunc(this, m_SGclientObject, m_SGclientInfo);
+		}
+	}
+
 
 	SG_IObject(
 		void* clientobj,
 		void* clientinfo,
-		SG_Callbacks callbacks
+		SG_Callbacks& callbacks
 	);
 
 	SG_IObject(
diff --git a/source/gameengine/SceneGraph/SG_Node.cpp b/source/gameengine/SceneGraph/SG_Node.cpp
index 64d9019c86a..c4a1b151846 100644
--- a/source/gameengine/SceneGraph/SG_Node.cpp
+++ b/source/gameengine/SceneGraph/SG_Node.cpp
@@ -40,7 +40,7 @@ using namespace std;
 SG_Node::SG_Node(
 	void* clientobj,
 	void* clientinfo,
-	SG_Callbacks callbacks
+	SG_Callbacks& callbacks
 
 )
 	: SG_Spatial(clientobj,clientinfo,callbacks),
@@ -141,22 +141,6 @@ Destruct()
 	ActivateDestructionCallback();
 }
 
-
-	SG_Node*			
-SG_Node::
-GetSGParent(
-) const { 
-	return m_SGparent;
-}
-
-	void				
-SG_Node::
-SetSGParent(
-	SG_Node* parent
-){
-	m_SGparent = parent;
-}
-
 const 
 	SG_Node*	
 SG_Node::
@@ -165,28 +149,6 @@ GetRootSGParent(
 	return (m_SGparent ? (const SG_Node*) m_SGparent->GetRootSGParent() : (const SG_Node*) this);
 }
 
-	bool
-SG_Node::
-IsVertexParent()
-{
-	if (m_parent_relation)
-	{
-		return m_parent_relation->IsVertexRelation();
-	}
-	return false;
-}
-
-	bool
-SG_Node::
-IsSlowParent()
-{
-	if (m_parent_relation)
-	{
-		return m_parent_relation->IsSlowRelation();
-	}
-	return false;
-}
-
 	void 
 SG_Node::
 DisconnectFromParent(
@@ -199,8 +161,6 @@ DisconnectFromParent(
 
 }
 
-
-
 void SG_Node::AddChild(SG_Node* child)
 {
 	m_children.push_back(child);
@@ -228,6 +188,9 @@ void SG_Node::UpdateWorldData(double time, bool parentUpdated)
 		// to update the 
 		ActivateUpdateTransformCallback();
 
+	// The node is updated, remove it from the update list
+	Delink();
+
 	// update children's worlddata
 	for (NodeList::iterator it = m_children.begin();it!=m_children.end();++it)
 	{
@@ -236,24 +199,6 @@ void SG_Node::UpdateWorldData(double time, bool parentUpdated)
 }
 
 
-NodeList& SG_Node::GetSGChildren()
-{
-	return this->m_children;
-}
-
-
-const NodeList& SG_Node::GetSGChildren() const
-{
-	return this->m_children;
-}
-
-
-void SG_Node::ClearSGChildren()
-{
-	m_children.clear();
-}
-
-
 
 void SG_Node::SetSimulatedTime(double time,bool recurse)
 {
diff --git a/source/gameengine/SceneGraph/SG_Node.h b/source/gameengine/SceneGraph/SG_Node.h
index 29943653a81..7c6ef92f670 100644
--- a/source/gameengine/SceneGraph/SG_Node.h
+++ b/source/gameengine/SceneGraph/SG_Node.h
@@ -44,7 +44,7 @@ public:
 	SG_Node(
 		void* clientobj,
 		void* clientinfo,
-		SG_Callbacks callbacks
+		SG_Callbacks& callbacks
 	);
 
 	SG_Node(
@@ -85,45 +85,47 @@ public:
 	 * @return a reference to the list of children of this node.
 	 */
 	
-		NodeList&		
-	GetSGChildren(
-	);
+	NodeList& GetSGChildren()
+	{
+		return this->m_children;
+	}
 
 	/**
 	 * Get the current list of children.
 	 * @return a const reference to the current list of children of this node.
 	 */
 
-	const 
-		NodeList&	
-	GetSGChildren(
-	) const;
+	const NodeList& GetSGChildren() const
+	{
+		return this->m_children;
+	}
 
 	/** 
 	 * Clear the list of children associated with this node
 	 */
 
-		void				
-	ClearSGChildren(
-	);
+	void ClearSGChildren()
+	{
+		m_children.clear();
+	}
 
 	/**
 	 * return the parent of this node if it exists.
 	 */
 		
-		SG_Node*			
-	GetSGParent(
-	) const ;
-
+	SG_Node* GetSGParent() const 
+	{ 
+		return m_SGparent;
+	}
 
 	/**
 	 * Set the parent of this node. 
 	 */
 
-		void				
-	SetSGParent(
-		SG_Node* parent
-	);
+	void SetSGParent(SG_Node* parent)
+	{
+		m_SGparent = parent;
+	}
 
 	/**
 	 * Return the top node in this node's Scene graph hierarchy
@@ -143,30 +145,33 @@ public:
 	);
 
 	/**
-	 * Tell this node to treat it's parent as a vertex parent.
-	 */
-
-		void	
-	SetVertexParent(
-		bool isvertexparent
-	) ;
-
-
-	/**
 	 * Return vertex parent status.
 	 */
+	bool IsVertexParent()
+	{
+		if (m_parent_relation)
+		{
+			return m_parent_relation->IsVertexRelation();
+		}
+		return false;
+	}
+
 
-		bool	
-	IsVertexParent(
-	) ;
-	
 	/**
 	 * Return slow parent status.
 	 */
 
-		bool	
-	IsSlowParent(
-	) ;
+	bool IsSlowParent()
+	{
+		if (m_parent_relation)
+		{
+			return m_parent_relation->IsSlowRelation();
+		}
+		return false;
+	}
+
+
+
 
 	/**		
 	 * Update the spatial data of this node. Iterate through
@@ -191,6 +196,42 @@ public:
 	);
 
 	/**
+	 * Schedule this node for update by placing it in head queue
+	 */
+	bool Schedule(SG_QList& head)
+	{
+		// Put top parent in front of list to make sure they are updated before their
+		// children => the children will be udpated and removed from the list before
+		// we get to them, should they be in the list too.
+		return (m_SGparent)?head.AddBack(this):head.AddFront(this);
+	}
+
+	/**
+	 * Used during Scenegraph update
+	 */
+	static SG_Node* GetNextScheduled(SG_QList& head)
+	{
+		return static_cast<SG_Node*>(head.Remove());
+	}
+
+	/**
+	 * Make this node ready for schedule on next update. This is needed for nodes
+	 * that must always be updated (slow parent, bone parent)
+	 */
+	bool Reschedule(SG_QList& head)
+	{
+		return head.QAddBack(this);
+	}
+
+	/**
+	 * Used during Scenegraph update
+	 */
+	static SG_Node* GetNextRescheduled(SG_QList& head)
+	{
+		return static_cast<SG_Node*>(head.QRemove());
+	}
+
+	/**
 	 * Node replication functions.
 	 */
 
diff --git a/source/gameengine/SceneGraph/SG_QList.h b/source/gameengine/SceneGraph/SG_QList.h
new file mode 100644
index 00000000000..efaa613bbb9
--- /dev/null
+++ b/source/gameengine/SceneGraph/SG_QList.h
@@ -0,0 +1,144 @@
+/**
+ * $Id$
+ *
+ * ***** BEGIN GPL LICENSE BLOCK *****
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ *
+ * The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
+ * All rights reserved.
+ *
+ * The Original Code is: all of this file.
+ *
+ * Contributor(s): none yet.
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ */
+#ifndef __SG_QLIST
+#define __SG_QLIST
+
+#include "SG_DList.h"
+
+/**
+ * Double-Double circular linked list
+ * For storing an object is two lists simultaneously
+ */
+class SG_QList : public SG_DList
+{
+protected :
+	SG_QList* m_fqlink;
+	SG_QList* m_bqlink;
+
+public:
+	template<typename T> class iterator
+	{
+	private:
+		SG_QList&	m_head;
+		T*			m_current;
+	public:
+		typedef iterator<T> _myT;
+		iterator(SG_QList& head) : m_head(head), m_current(NULL) {}
+		~iterator() {}
+
+		void begin()
+		{
+			m_current = (T*)m_head.QPeek();
+			if (m_current == (T*)m_head.Self())
+			{
+				m_current = NULL;
+			}
+		}
+		bool end()
+		{
+			return (NULL == m_current);
+		}
+		T* operator*()
+		{
+			return m_current;
+		}
+		_myT& operator++()
+		{
+			assert(m_current);
+			m_current = (T*)m_current->QPeek();
+			if (m_current == (T*)m_head.Self())
+			{
+				m_current = NULL;
+			}
+			return *this;
+		}
+	};
+
+	SG_QList() : SG_DList()
+    { 
+        m_fqlink = m_bqlink = this; 
+    }
+    virtual ~SG_QList() 
+    {
+		QDelink();
+    }
+
+    inline bool QEmpty()               // Check for empty queue
+    {     
+        return ( m_fqlink == this ); 
+    }
+    bool QAddBack( SG_QList *item )  // Add to the back
+    {
+		if (!item->QEmpty())
+			return false;
+        item->m_bqlink = m_bqlink;
+        item->m_fqlink = this;
+        m_bqlink->m_fqlink = item;
+        m_bqlink = item;
+		return true;
+    }
+    bool QAddFront( SG_QList *item )  // Add to the back
+    {
+		if (!item->Empty())
+			return false;
+        item->m_fqlink = m_fqlink;
+        item->m_bqlink = this;
+        m_fqlink->m_bqlink = item;
+        m_fqlink = item;
+		return true;
+    }
+    SG_QList *QRemove()           // Remove from the front
+    {
+        if (QEmpty()) 
+        {
+            return NULL;
+        }
+        SG_QList* item = m_fqlink;
+        m_fqlink = item->m_fqlink;
+        m_fqlink->m_bqlink = this;
+        item->m_fqlink = item->m_bqlink = item;
+        return item;
+    }
+    void QDelink()             // Remove from the middle
+    {
+		if (!QEmpty())
+		{
+			m_bqlink->m_fqlink = m_fqlink;
+			m_fqlink->m_bqlink = m_bqlink;
+			m_fqlink = m_bqlink = this;
+		}
+    }
+    inline SG_QList *QPeek()			// Look at front without removing
+    { 
+        return m_fqlink; 
+    }  
+};
+
+#endif //__SG_QLIST
+
diff --git a/source/gameengine/SceneGraph/SG_Spatial.cpp b/source/gameengine/SceneGraph/SG_Spatial.cpp
index 2f3176816c6..97b15bdf376 100644
--- a/source/gameengine/SceneGraph/SG_Spatial.cpp
+++ b/source/gameengine/SceneGraph/SG_Spatial.cpp
@@ -40,7 +40,7 @@ SG_Spatial::
 SG_Spatial(
 	void* clientobj,
 	void* clientinfo,
-	SG_Callbacks callbacks
+	SG_Callbacks& callbacks
 ): 
 
 	SG_IObject(clientobj,clientinfo,callbacks),
@@ -56,8 +56,9 @@ SG_Spatial(
 	
 	m_bbox(MT_Point3(-1.0, -1.0, -1.0), MT_Point3(1.0, 1.0, 1.0)),
 	m_radius(1.0),
-	m_modified(true)
+	m_modified(false)
 {
+	SetModified();
 }
 
 SG_Spatial::
@@ -88,13 +89,6 @@ SG_Spatial::
 	delete (m_parent_relation);
 }
 
-	SG_ParentRelation *
-SG_Spatial::
-GetParentRelation(
-){
-	return m_parent_relation;
-}
-
 	void
 SG_Spatial::
 SetParentRelation(
@@ -102,7 +96,7 @@ SetParentRelation(
 ){
 	delete (m_parent_relation);
 	m_parent_relation = relation;
-	m_modified = true;
+	SetModified();
 }
 
 
@@ -143,11 +137,6 @@ UpdateSpatialData(
 	return bComputesWorldTransform;
 }
 
-bool	SG_Spatial::ComputeWorldTransforms(const SG_Spatial *parent, bool& parentUpdated)
-{
-	return m_parent_relation->UpdateChildCoordinates(this,parent,parentUpdated);
-}
-
 /**
  * Position and translation methods
  */
@@ -169,56 +158,14 @@ RelativeTranslate(
 			m_localPosition += trans;
 		}
 	}
-	m_modified = true;
+	SetModified();
 }	
 	
-	void 
-SG_Spatial::
-SetLocalPosition(
-	const MT_Point3& trans
-){
-	m_localPosition = trans;
-	m_modified = true;
-}
-
-	void				
-SG_Spatial::
-SetWorldPosition(
-	const MT_Point3& trans
-) {
-	m_worldPosition = trans;
-}
 
 /**
  * Scaling methods.
  */ 
 
-	void 
-SG_Spatial::
-RelativeScale(
-	const MT_Vector3& scale
-){
-	m_localScaling = m_localScaling * scale;
-	m_modified = true;
-}
-
-	void 
-SG_Spatial::
-SetLocalScale(
-	const MT_Vector3& scale
-){
-	m_localScaling = scale;
-	m_modified = true;
-}
-
-
-	void				
-SG_Spatial::
-SetWorldScale(
-	const MT_Vector3& scale
-){ 
-	m_worldScaling = scale;
-}
 
 /**
  * Orientation and rotation methods.
@@ -236,93 +183,11 @@ RelativeRotate(
 		rot 
 	:
 	(GetWorldOrientation().inverse() * rot * GetWorldOrientation()));
-	m_modified = true;
-}
-
-	void 
-SG_Spatial::
-SetLocalOrientation(const MT_Matrix3x3& rot)
-{
-	m_localRotation = rot;
-	m_modified = true;
+	SetModified();
 }
 
 
 
-	void				
-SG_Spatial::
-SetWorldOrientation(
-	const MT_Matrix3x3& rot
-) {
-	m_worldRotation = rot;
-}
-
-const 
-	MT_Point3&
-SG_Spatial::
-GetLocalPosition(
-) const	{
-	 return m_localPosition;
-}
-
-const 
-	MT_Matrix3x3&
-SG_Spatial::
-GetLocalOrientation(
-) const	{
-	return m_localRotation;
-}
-
-const 
-	MT_Vector3&	
-SG_Spatial::
-GetLocalScale(
-) const{
-	return m_localScaling;
-}
-
-
-const 
-	MT_Point3&
-SG_Spatial::
-GetWorldPosition(
-) const	{
-	return m_worldPosition;
-}
-
-const 
-	MT_Matrix3x3&	
-SG_Spatial::
-GetWorldOrientation(
-) const	{
-	return m_worldRotation;
-}
-
-const 
-	MT_Vector3&	
-SG_Spatial::
-GetWorldScaling(
-) const	{
-	return m_worldScaling;
-}
-
-void SG_Spatial::SetWorldFromLocalTransform()
-{
-	m_worldPosition= m_localPosition;
-	m_worldScaling= m_localScaling;
-	m_worldRotation= m_localRotation;
-}
-
-SG_BBox& SG_Spatial::BBox()
-{
-	return m_bbox;
-}
-
-void SG_Spatial::SetBBox(SG_BBox& bbox)
-{
-	m_bbox = bbox;
-}
-
 MT_Transform SG_Spatial::GetWorldTransform() const
 {
 	return MT_Transform(m_worldPosition, 
diff --git a/source/gameengine/SceneGraph/SG_Spatial.h b/source/gameengine/SceneGraph/SG_Spatial.h
index c2ed80d21b2..eb1e87fbf19 100644
--- a/source/gameengine/SceneGraph/SG_Spatial.h
+++ b/source/gameengine/SceneGraph/SG_Spatial.h
@@ -35,6 +35,7 @@
 #include <MT_Matrix3x3.h> // or Quaternion later ?
 #include "SG_IObject.h"
 #include "SG_BBox.h"
+#include "SG_ParentRelation.h"
 
 
 class SG_Node;
@@ -65,6 +66,16 @@ protected:
 
 public:
 
+	inline void ClearModified() 
+	{ 
+		m_modified = false; 
+	}
+	inline void SetModified()
+	{
+		m_modified = true;
+		ActivateScheduleUpdateCallback();
+	}
+
 	/** 
 	 * Define the realtionship this node has with it's parent
 	 * node. You should pass an unshared instance of an SG_ParentRelation
@@ -84,9 +95,12 @@ public:
 		SG_ParentRelation *relation
 	);
 	
-		SG_ParentRelation *
-	GetParentRelation(
-	);
+	SG_ParentRelation * GetParentRelation()
+	{
+		return m_parent_relation;
+	}
+
+
 
 
 	/**
@@ -105,15 +119,17 @@ public:
 		bool local
 	);
 
-		void				
-	SetLocalPosition(
-		const MT_Point3& trans
-	);
+	void SetLocalPosition(const MT_Point3& trans)
+	{
+		m_localPosition = trans;
+		SetModified();
+	}
+
+	void SetWorldPosition(const MT_Point3& trans)
+	{
+		m_worldPosition = trans;
+	}
 
-		void				
-	SetWorldPosition(
-		const MT_Point3& trans
-	);
 	
 		void				
 	RelativeRotate(
@@ -121,72 +137,95 @@ public:
 		bool local
 	);
 
-		void				
-	SetLocalOrientation(
-		const MT_Matrix3x3& rot
-	);
-
-		void				
-	SetWorldOrientation(
-		const MT_Matrix3x3& rot
-	);
-
-		void				
-	RelativeScale(
-		const MT_Vector3& scale
-	);
-
-		void				
-	SetLocalScale(
-		const MT_Vector3& scale
-	);
-
-		void				
-	SetWorldScale(
-		const MT_Vector3& scale
-	);
-
-	const 
-		MT_Point3&
-	GetLocalPosition(
-	) const	;
+	void SetLocalOrientation(const MT_Matrix3x3& rot)
+	{
+		m_localRotation = rot;
+		SetModified();
+	}
+
+	void SetWorldOrientation(const MT_Matrix3x3& rot) 
+	{
+		m_worldRotation = rot;
+	}
+
+	void RelativeScale(const MT_Vector3& scale)
+	{
+		m_localScaling = m_localScaling * scale;
+		SetModified();
+	}
+
+	void SetLocalScale(const MT_Vector3& scale)
+	{
+		m_localScaling = scale;
+		SetModified();
+	}
+
+	void SetWorldScale(const MT_Vector3& scale)
+	{ 
+		m_worldScaling = scale;
+	}
+
+	const MT_Point3& GetLocalPosition() const	
+	{
+		return m_localPosition;
+	}
+
+	const MT_Matrix3x3& GetLocalOrientation() const	
+	{
+		return m_localRotation;
+	}
+
+	const MT_Vector3& GetLocalScale() const
+	{
+		return m_localScaling;
+	}
+
+	const MT_Point3& GetWorldPosition() const	
+	{
+		return m_worldPosition;
+	}
+
+	const MT_Matrix3x3&	GetWorldOrientation() const	
+	{
+		return m_worldRotation;
+	}
+
+	const MT_Vector3& GetWorldScaling() const	
+	{
+		return m_worldScaling;
+	}
+
+	void SetWorldFromLocalTransform()
+	{
+		m_worldPosition= m_localPosition;
+		m_worldScaling= m_localScaling;
+		m_worldRotation= m_localRotation;
+	}
 
-	const 
-		MT_Matrix3x3&
-	GetLocalOrientation(
-	) const	;
 
-	const 
-		MT_Vector3&	
-	GetLocalScale(
-	) const;
-
-	const 
-		MT_Point3&
-	GetWorldPosition(
-	) const	;
-
-	const 
-		MT_Matrix3x3&	
-	GetWorldOrientation(
-	) const	;
-
-	const 
-		MT_Vector3&	
-	GetWorldScaling(
-	) const	;
-
-	void SetWorldFromLocalTransform();
 
 	MT_Transform GetWorldTransform() const;
 
-	bool	ComputeWorldTransforms(const SG_Spatial *parent, bool& parentUpdated);
+	bool	ComputeWorldTransforms(const SG_Spatial *parent, bool& parentUpdated)
+	{
+		return m_parent_relation->UpdateChildCoordinates(this,parent,parentUpdated);
+	}
+
 
 	/**
 	 * Bounding box functions.
 	 */
-	SG_BBox& BBox();
-	void SetBBox(SG_BBox & bbox);
+	SG_BBox& BBox()
+	{
+		return m_bbox;
+	}
+
+	void SetBBox(SG_BBox& bbox)
+	{
+		m_bbox = bbox;
+	}
+
+
 	bool inside(const MT_Point3 &point) const;
 	void getBBox(MT_Point3 *box) const;
 	void getAABBox(MT_Point3 *box) const;
@@ -210,7 +249,7 @@ protected:
 	SG_Spatial(
 		void* clientobj,
 		void* clientinfo,
-		SG_Callbacks callbacks
+		SG_Callbacks& callbacks
 	);
 
 	SG_Spatial(
@@ -231,7 +270,6 @@ protected:
 		double time,
 		bool& parentUpdated
 	);
-	void SetModified(bool modified) { m_modified = modified; }
 
 };