From 94891778c40ff08fcc626f91ded73cda67713b36 Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Fri, 12 Aug 2016 18:44:38 +0100
Subject: [PATCH] Restructred the enabling of vertex array object support to
 allow one to set enable the default via osg::State.

Added OSG_VERTEX_BUFFER_HINT env var to osg::DisplaySettings with VERTEX_BUFFER_OBJECT/VBO, VERTEX_ARRAY_OBJECT/VAO and NO_PREFERENCE to allow one to foce on VBO or VAO usage.

Restructred BufferObject assigned in osg::Geometry

Added
---
 include/osg/DisplaySettings  | 12 ++---
 include/osg/Drawable         | 51 ++++----------------
 include/osg/State            |  7 +--
 include/osg/VertexArrayState |  2 +
 src/osg/DisplaySettings.cpp  | 30 ++++++------
 src/osg/Drawable.cpp         | 91 ++++++++++++++++++++++++++++++++----
 src/osg/Geometry.cpp         | 76 +++++++++++++++---------------
 src/osg/PrimitiveSet.cpp     |  9 ++--
 src/osg/State.cpp            |  7 ++-
 src/osg/VertexArrayState.cpp |  6 +++
 10 files changed, 175 insertions(+), 116 deletions(-)

diff --git a/include/osg/DisplaySettings b/include/osg/DisplaySettings
index 9645b1670..060ec6ec9 100644
--- a/include/osg/DisplaySettings
+++ b/include/osg/DisplaySettings
@@ -299,15 +299,15 @@ class OSG_EXPORT DisplaySettings : public osg::Referenced
         int getNvOptimusEnablement() const;
 
 
-        enum GeometryImplementation
+        enum VertexBufferHint
         {
-            OLD_GEOMETRY_IMPLEMENTATION,
-            NEW_GEOMETRY_IMPLEMENTATION,
+            NO_PREFERENCE,
+            VERTEX_BUFFER_OBJECT,
             VERTEX_ARRAY_OBJECT
         };
 
-        void setGeometryImplementation(GeometryImplementation gi) { _geometryImplementation = gi; }
-        GeometryImplementation getGeometryImplementation() const { return _geometryImplementation; }
+        void setVertexBufferHint(VertexBufferHint gi) { _vertexBufferHint = gi; }
+        VertexBufferHint getVertexBufferHint() const { return _vertexBufferHint; }
 
 
         void setKeystoneHint(bool enabled) { _keystoneHint = enabled; }
@@ -399,7 +399,7 @@ class OSG_EXPORT DisplaySettings : public osg::Referenced
         SwapMethod                      _swapMethod;
         unsigned int                    _syncSwapBuffers;
 
-        GeometryImplementation          _geometryImplementation;
+        VertexBufferHint                _vertexBufferHint;
 
         bool                            _keystoneHint;
         FileNames                       _keystoneFileNames;
diff --git a/include/osg/Drawable b/include/osg/Drawable
index 0a2d5700a..0c828e828 100644
--- a/include/osg/Drawable
+++ b/include/osg/Drawable
@@ -55,6 +55,8 @@
 #endif
 
 
+#define INLINE_DRAWABLE_DRAW
+
 namespace osg {
 
 
@@ -256,7 +258,11 @@ class OSG_EXPORT Drawable : public Node
           *       \c virtual). Subclasses should override
           *       \c drawImplementation() instead.
           */
+#ifdef INLINE_DRAWABLE_DRAW
         inline void draw(RenderInfo& renderInfo) const;
+#else
+        void draw(RenderInfo& renderInfo) const;
+#endif
 
         inline void drawInner(RenderInfo& renderInfo) const
         {
@@ -491,12 +497,11 @@ class OSG_EXPORT Drawable : public Node
         ref_ptr<DrawCallback>   _drawCallback;
 };
 
-#if 1
+#ifdef INLINE_DRAWABLE_DRAW
 inline void Drawable::draw(RenderInfo& renderInfo) const
 {
     State& state = *renderInfo.getState();
-    bool useVertexArrayObject = _useVertexBufferObjects && state.useVertexArrayObject();
-
+    bool useVertexArrayObject = state.useVertexArrayObject(_useVertexArrayObject);
     if (useVertexArrayObject)
     {
         unsigned int contextID = renderInfo.getContextID();
@@ -560,46 +565,6 @@ inline void Drawable::draw(RenderInfo& renderInfo) const
         drawInner(renderInfo);
     }
 }
-#else
-inline void Drawable::draw(RenderInfo& renderInfo) const
-{
-#ifdef OSG_GL_DISPLAYLISTS_AVAILABLE
-    if (_useDisplayList && !(_supportsVertexBufferObjects && _useVertexBufferObjects && renderInfo.getState()->isVertexBufferObjectSupported()))
-    {
-        // get the contextID (user defined ID of 0 upwards) for the
-        // current OpenGL context.
-        unsigned int contextID = renderInfo.getContextID();
-
-        // get the globj for the current contextID.
-        GLuint& globj = _globjList[contextID];
-
-        if( globj == 0 )
-        {
-            // compile the display list
-            globj = generateDisplayList(contextID, getGLObjectSizeHint());
-            glNewList( globj, GL_COMPILE );
-
-            if (_drawCallback.valid())
-                _drawCallback->drawImplementation(renderInfo,this);
-            else
-                drawImplementation(renderInfo);
-
-            glEndList();
-        }
-
-        // call the display list
-        glCallList( globj);
-
-        return;
-    }
-#endif
-
-    // draw object as nature intended..
-    if (_drawCallback.valid())
-        _drawCallback->drawImplementation(renderInfo,this);
-    else
-        drawImplementation(renderInfo);
-}
 #endif
 
 class AttributeFunctorArrayVisitor : public ArrayVisitor
diff --git a/include/osg/State b/include/osg/State
index 570cac5aa..7bb302137 100644
--- a/include/osg/State
+++ b/include/osg/State
@@ -716,10 +716,11 @@ class OSG_EXPORT State : public Referenced
 
 
         inline bool isVertexBufferObjectSupported() const { return _isVertexBufferObjectSupported; }
+        inline bool useVertexBufferObject(bool useVBO) const { return _forceVertexBufferObject || (_isVertexBufferObjectSupported && useVBO); }
 
         inline bool isVertexArrayObjectSupported() const { return _isVertexArrayObjectSupported; }
+        inline bool useVertexArrayObject(bool useVAO) const { return _forceVertexArrayObject || (_isVertexArrayObjectSupported && useVAO); }
 
-        inline bool useVertexArrayObject() const { return _useVertexArrayObject; }
 
         inline void setLastAppliedProgramObject(const Program::PerContextProgram* program)
         {
@@ -1306,8 +1307,8 @@ class OSG_EXPORT State : public Referenced
         bool _isFogCoordSupported;
         bool _isVertexBufferObjectSupported;
         bool _isVertexArrayObjectSupported;
-
-        bool _useVertexArrayObject;
+        bool _forceVertexBufferObject;
+        bool _forceVertexArrayObject;
 
         typedef void (GL_APIENTRY * ActiveTextureProc) (GLenum texture);
         typedef void (GL_APIENTRY * FogCoordPointerProc) (GLenum type, GLsizei stride, const GLvoid *pointer);
diff --git a/include/osg/VertexArrayState b/include/osg/VertexArrayState
index 62085b224..bd09b5fc5 100644
--- a/include/osg/VertexArrayState
+++ b/include/osg/VertexArrayState
@@ -161,6 +161,8 @@ public:
         void setRequiresSetArrays(bool flag) { _requiresSetArrays = flag; }
         bool getRequiresSetArrays() const { return _requiresSetArrays; }
 
+        void dirty();
+
         void release();
 
 public:
diff --git a/src/osg/DisplaySettings.cpp b/src/osg/DisplaySettings.cpp
index 128ed9ca8..0aadd67dd 100644
--- a/src/osg/DisplaySettings.cpp
+++ b/src/osg/DisplaySettings.cpp
@@ -116,7 +116,7 @@ void DisplaySettings::setDisplaySettings(const DisplaySettings& vs)
     _glContextProfileMask = vs._glContextProfileMask;
     _swapMethod = vs._swapMethod;
 
-    _geometryImplementation = vs._geometryImplementation;
+    _vertexBufferHint = vs._vertexBufferHint;
 
     _keystoneHint = vs._keystoneHint;
     _keystoneFileNames = vs._keystoneFileNames;
@@ -243,8 +243,9 @@ void DisplaySettings::setDefaults()
     _swapMethod = SWAP_DEFAULT;
     _syncSwapBuffers = 0;
 
-    // _geometryImplementation = VERTEX_ARRAY_OBJECT;
-    _geometryImplementation = OLD_GEOMETRY_IMPLEMENTATION;
+    _vertexBufferHint = NO_PREFERENCE;
+    // _vertexBufferHint = VERTEX_BUFFER_OBJECT;
+    // _vertexBufferHint = VERTEX_ARRAY_OBJECT;
 
     _keystoneHint = false;
 
@@ -367,8 +368,8 @@ static ApplicationUsageProxy DisplaySetting_e31(ApplicationUsage::ENVIRONMENTAL_
         "OSG_NvOptimusEnablement <value>",
         "Set the hint to NvOptimus of whether to enable it or not, set 1 to enable, 0 to disable");
 static ApplicationUsageProxy DisplaySetting_e32(ApplicationUsage::ENVIRONMENTAL_VARIABLE,
-        "OSG_GEOMETRY_IMPLEMENTATION <value>",
-        "Set the hint to what backend osg::Geometry implementation to use. OLD | NEW | VERTEX_ARRAY_OBJECT");
+        "OSG_VERTEX_BUFFER_HINT <value>",
+        "Set the hint to what backend osg::Geometry implementation to use. NO_PREFERENCE | VERTEX_BUFFER_OBJECT | VERTEX_ARRAY_OBJECT");
 
 void DisplaySettings::readEnvironmentalVariables()
 {
@@ -680,19 +681,22 @@ void DisplaySettings::readEnvironmentalVariables()
     }
 
 
-    if ((ptr = getenv("OSG_GEOMETRY_IMPLEMENTATION")) != 0)
+    if ((ptr = getenv("OSG_VERTEX_BUFFER_HINT")) != 0)
     {
-        if (strcmp(ptr,"OLD")==0)
+        if (strcmp(ptr,"VERTEX_BUFFER_OBJECT")==0 || strcmp(ptr,"VBO")==0)
         {
-            _geometryImplementation = OLD_GEOMETRY_IMPLEMENTATION;
-        }
-        else if (strcmp(ptr,"NEW")==0 )
-        {
-            _geometryImplementation = NEW_GEOMETRY_IMPLEMENTATION;
+            OSG_NOTICE<<"OSG_VERTEX_BUFFER_HINT set to VERTEX_BUFFER_OBJECT"<<std::endl;
+            _vertexBufferHint = VERTEX_BUFFER_OBJECT;
         }
         else if (strcmp(ptr,"VERTEX_ARRAY_OBJECT")==0 || strcmp(ptr,"VAO")==0)
         {
-            _geometryImplementation =  VERTEX_ARRAY_OBJECT;
+            OSG_NOTICE<<"OSG_VERTEX_BUFFER_HINT set to VERTEX_ARRAY_OBJECT"<<std::endl;
+            _vertexBufferHint = VERTEX_ARRAY_OBJECT;
+        }
+        else
+        {
+            OSG_NOTICE<<"OSG_VERTEX_BUFFER_HINT set to NO_PREFERENCE"<<std::endl;
+            _vertexBufferHint = NO_PREFERENCE;
         }
     }
 
diff --git a/src/osg/Drawable.cpp b/src/osg/Drawable.cpp
index 370265852..4800530fc 100644
--- a/src/osg/Drawable.cpp
+++ b/src/osg/Drawable.cpp
@@ -232,7 +232,7 @@ Drawable::Drawable()
     _useVertexBufferObjects = false;
 #else
     _supportsVertexBufferObjects = true;
-    _useVertexBufferObjects = false;
+    _useVertexBufferObjects = true;
 #endif
 
     _useVertexArrayObject = false;
@@ -426,7 +426,7 @@ void Drawable::setUseVertexBufferObjects(bool flag)
     // if was previously set to true, remove display list.
     if (_useVertexBufferObjects)
     {
-        dirtyDisplayList();
+        dirtyGLObjects();
     }
 
     _useVertexBufferObjects = flag;
@@ -454,11 +454,7 @@ void Drawable::dirtyGLObjects()
     for(i=0; i<_vertexArrayStateList.size(); ++i)
     {
         VertexArrayState* vas = _vertexArrayStateList[i].get();
-        if (vas)
-        {
-            vas->release();
-            _vertexArrayStateList[i] = 0;
-        }
+        if (vas) vas->dirty();
     }
 }
 
@@ -624,7 +620,86 @@ void Drawable::compileGLObjects(RenderInfo& renderInfo) const
 #endif
 }
 
+#ifndef INLINE_DRAWABLE_DRAW
+
+void Drawable::draw(RenderInfo& renderInfo) const
+{
+    // OSG_NOTICE<<"Geometry::draw() "<<this<<std::endl;
+
+    State& state = *renderInfo.getState();
+    bool useVertexArrayObject = state.useVertexArrayObject(_useVertexArrayObject);
+    if (useVertexArrayObject)
+    {
+        unsigned int contextID = renderInfo.getContextID();
+
+        VertexArrayState* vas = _vertexArrayStateList[contextID].get();
+        if (!vas)
+        {
+            _vertexArrayStateList[contextID] = vas = createVertexArrayState(renderInfo, true);
+            // OSG_NOTICE<<"  Geometry::draw() "<<this<<", assigned _vertexArrayStateList[renderInfo.getContextID()]="<<_vertexArrayStateList[renderInfo.getContextID()].get()<<", vas="<<vas<< std::endl;
+        }
+        else
+        {
+            // vas->setRequiresSetArrays(getDataVariance()==osg::Object::DYNAMIC);
+            // OSG_NOTICE<<"  Geometry::draw() "<<this<<", reusing _vertexArrayStateList[renderInfo.getContextID()]="<<_vertexArrayStateList[renderInfo.getContextID()].get()<<", vas="<<vas<< std::endl;
+        }
+
+
+        State::SetCurrentVertexArrayStateProxy setVASProxy(state, vas);
+
+        vas->bindVertexArrayObject();
+
+        drawInner(renderInfo);
+
+        vas->setRequiresSetArrays(getDataVariance()==osg::Object::DYNAMIC);
+
+        return;
+    }
+
+    // TODO, add check against whether VOA is active and supported
+    if (state.getCurrentVertexArrayState()) state.getCurrentVertexArrayState()->bindVertexArrayObject();
+
+
+#ifdef OSG_GL_DISPLAYLISTS_AVAILABLE
+    if (_useDisplayList)
+    {
+        // get the contextID (user defined ID of 0 upwards) for the
+        // current OpenGL context.
+        unsigned int contextID = renderInfo.getContextID();
+
+        // get the globj for the current contextID.
+        GLuint& globj = _globjList[contextID];
+
+        if( globj == 0 )
+        {
+            // compile the display list
+            globj = generateDisplayList(contextID, getGLObjectSizeHint());
+            glNewList( globj, GL_COMPILE );
+
+            drawInner(renderInfo);
+
+            glEndList();
+        }
+
+        // call the display list
+        glCallList( globj);
+    }
+    else
+#endif
+    {
+        // if state.previousVertexArrayState() is different than currentVertexArrayState bind current
+
+        // OSG_NOTICE<<"Fallback drawInner()........................"<<std::endl;
+
+        drawInner(renderInfo);
+    }
+}
+
+#endif
+
 VertexArrayState* Drawable::createVertexArrayState(RenderInfo& renderInfo, bool usingVBOs) const
 {
-    return new osg::VertexArrayState(renderInfo.getState());
+    VertexArrayState* vos = new osg::VertexArrayState(renderInfo.getState());
+    vos->assignAllDispatchers();
+    return vos;
 }
diff --git a/src/osg/Geometry.cpp b/src/osg/Geometry.cpp
index b320e6e67..c690fcb7a 100644
--- a/src/osg/Geometry.cpp
+++ b/src/osg/Geometry.cpp
@@ -70,7 +70,7 @@ Geometry::Geometry(const Geometry& geometry,const CopyOp& copyop):
 
     if ((copyop.getCopyFlags() & osg::CopyOp::DEEP_COPY_ARRAYS) || (copyop.getCopyFlags() & osg::CopyOp::DEEP_COPY_PRIMITIVES))
     {
-        if (_useVertexBufferObjects)
+        /*if (_useVertexBufferObjects)*/
         {
             // copying of arrays doesn't set up buffer objects so we'll need to force
             // Geometry to assign these, we'll do this by changing the cached value to false then re-enabling.
@@ -114,7 +114,7 @@ void Geometry::setVertexArray(Array* array)
     dirtyDisplayList();
     dirtyBound();
 
-    if (_useVertexBufferObjects && array) addVertexBufferObjectIfRequired(array);
+    if (/*_useVertexBufferObjects && */array) addVertexBufferObjectIfRequired(array);
 }
 
 void Geometry::setNormalArray(Array* array, osg::Array::Binding binding)
@@ -125,7 +125,7 @@ void Geometry::setNormalArray(Array* array, osg::Array::Binding binding)
 
     dirtyDisplayList();
 
-    if (_useVertexBufferObjects && array) addVertexBufferObjectIfRequired(array);
+    if (/*_useVertexBufferObjects && */array) addVertexBufferObjectIfRequired(array);
 }
 
 void Geometry::setColorArray(Array* array, osg::Array::Binding binding)
@@ -136,7 +136,7 @@ void Geometry::setColorArray(Array* array, osg::Array::Binding binding)
 
     dirtyDisplayList();
 
-    if (_useVertexBufferObjects && array) addVertexBufferObjectIfRequired(array);
+    if (/*_useVertexBufferObjects && */array) addVertexBufferObjectIfRequired(array);
 }
 
 void Geometry::setSecondaryColorArray(Array* array, osg::Array::Binding binding)
@@ -147,7 +147,7 @@ void Geometry::setSecondaryColorArray(Array* array, osg::Array::Binding binding)
 
     dirtyDisplayList();
 
-    if (_useVertexBufferObjects && array) addVertexBufferObjectIfRequired(array);
+    if (/*_useVertexBufferObjects && */array) addVertexBufferObjectIfRequired(array);
 }
 
 void Geometry::setFogCoordArray(Array* array, osg::Array::Binding binding)
@@ -158,7 +158,7 @@ void Geometry::setFogCoordArray(Array* array, osg::Array::Binding binding)
 
     dirtyDisplayList();
 
-    if (_useVertexBufferObjects && array) addVertexBufferObjectIfRequired(array);
+    if (/*_useVertexBufferObjects && */array) addVertexBufferObjectIfRequired(array);
 }
 
 
@@ -178,7 +178,7 @@ void Geometry::setTexCoordArray(unsigned int index,Array* array, osg::Array::Bin
 
     dirtyDisplayList();
 
-    if (_useVertexBufferObjects && array)
+    if (/*_useVertexBufferObjects && */array)
     {
         addVertexBufferObjectIfRequired(array);
     }
@@ -202,7 +202,7 @@ void Geometry::setTexCoordArrayList(const ArrayList& arrayList)
 
     dirtyDisplayList();
 
-    if (_useVertexBufferObjects)
+    /*if (_useVertexBufferObjects)*/
     {
         for(ArrayList::iterator itr = _texCoordList.begin();
             itr != _texCoordList.end();
@@ -224,7 +224,7 @@ void Geometry::setVertexAttribArray(unsigned int index, Array* array, osg::Array
 
     dirtyDisplayList();
 
-    if (_useVertexBufferObjects && array) addVertexBufferObjectIfRequired(array);
+    if (/*_useVertexBufferObjects && */array) addVertexBufferObjectIfRequired(array);
 }
 
 Array *Geometry::getVertexAttribArray(unsigned int index)
@@ -245,7 +245,7 @@ void Geometry::setVertexAttribArrayList(const ArrayList& arrayList)
 
     dirtyDisplayList();
 
-    if (_useVertexBufferObjects)
+    /*if (_useVertexBufferObjects)*/
     {
         for(ArrayList::iterator itr = _vertexAttribList.begin();
             itr != _vertexAttribList.end();
@@ -261,7 +261,7 @@ bool Geometry::addPrimitiveSet(PrimitiveSet* primitiveset)
 {
     if (primitiveset)
     {
-        if (_useVertexBufferObjects) addElementBufferObjectIfRequired(primitiveset);
+        /*if (_useVertexBufferObjects)*/ addElementBufferObjectIfRequired(primitiveset);
 
         _primitives.push_back(primitiveset);
         dirtyDisplayList();
@@ -277,7 +277,7 @@ bool Geometry::setPrimitiveSet(unsigned int i,PrimitiveSet* primitiveset)
 {
     if (i<_primitives.size() && primitiveset)
     {
-        if (_useVertexBufferObjects) addElementBufferObjectIfRequired(primitiveset);
+        /*if (_useVertexBufferObjects)*/ addElementBufferObjectIfRequired(primitiveset);
 
         _primitives[i] = primitiveset;
         dirtyDisplayList();
@@ -293,7 +293,7 @@ bool Geometry::insertPrimitiveSet(unsigned int i,PrimitiveSet* primitiveset)
 
     if (primitiveset)
     {
-        if (_useVertexBufferObjects) addElementBufferObjectIfRequired(primitiveset);
+        /*if (_useVertexBufferObjects)*/ addElementBufferObjectIfRequired(primitiveset);
 
         if (i<_primitives.size())
         {
@@ -315,7 +315,7 @@ bool Geometry::insertPrimitiveSet(unsigned int i,PrimitiveSet* primitiveset)
 void Geometry::setPrimitiveSetList(const PrimitiveSetList& primitives)
 {
     _primitives = primitives;
-    if (_useVertexBufferObjects)
+    /*if (_useVertexBufferObjects)*/
     {
         for (unsigned int primitiveSetIndex=0;primitiveSetIndex<_primitives.size();++primitiveSetIndex)
         {
@@ -451,7 +451,7 @@ bool Geometry::getDrawElementsList(DrawElementsList& drawElementsList) const
 
 void Geometry::addVertexBufferObjectIfRequired(osg::Array* array)
 {
-    if (_useVertexBufferObjects)
+    /*if (_useVertexBufferObjects)*/
     {
         if (!array->getVertexBufferObject())
         {
@@ -462,7 +462,7 @@ void Geometry::addVertexBufferObjectIfRequired(osg::Array* array)
 
 void Geometry::addElementBufferObjectIfRequired(osg::PrimitiveSet* primitiveSet)
 {
-    if (_useVertexBufferObjects)
+    /*if (_useVertexBufferObjects)*/
     {
         osg::DrawElements* drawElements = primitiveSet->getDrawElements();
         if (drawElements && !drawElements->getElementBufferObject())
@@ -525,7 +525,7 @@ void Geometry::setUseVertexBufferObjects(bool flag)
     typedef std::vector<osg::VertexBufferObject*>  VertexBufferObjectList;
     typedef std::vector<osg::ElementBufferObject*>  ElementBufferObjectList;
 
-    if (_useVertexBufferObjects)
+    /*if (_useVertexBufferObjects)*/
     {
         if (!arrayList.empty())
         {
@@ -580,6 +580,7 @@ void Geometry::setUseVertexBufferObjects(bool flag)
             }
         }
     }
+    /*
     else
     {
         for(ArrayList::iterator vitr = arrayList.begin();
@@ -598,6 +599,7 @@ void Geometry::setUseVertexBufferObjects(bool flag)
             if (elements->getElementBufferObject()) elements->setElementBufferObject(0);
         }
     }
+    */
 }
 
 void Geometry::dirtyGLObjects()
@@ -636,7 +638,14 @@ void Geometry::releaseGLObjects(State* state) const
 {
     Drawable::releaseGLObjects(state);
 
-    if (state) _vertexArrayStateList[state->getContextID()];
+    if (state)
+    {
+        if (_vertexArrayStateList[state->getContextID()].valid())
+        {
+            _vertexArrayStateList[state->getContextID()]->release();
+            _vertexArrayStateList[state->getContextID()] = 0;
+        }
+    }
     else _vertexArrayStateList.clear();
 
     ArrayList arrays;
@@ -665,13 +674,11 @@ void Geometry::releaseGLObjects(State* state) const
 
 VertexArrayState* Geometry::createVertexArrayState(RenderInfo& renderInfo, bool usingVBOs) const
 {
-    OSG_NOTICE<<"Creating new osg::VertexArrayState"<<std::endl;
     State& state = *renderInfo.getState();
-    const DisplaySettings* ds = state.getDisplaySettings() ? state.getDisplaySettings() : osg::DisplaySettings::instance();
 
-    VertexArrayState* vas = 0;
+    VertexArrayState* vas = new osg::VertexArrayState(&state);
 
-    _vertexArrayStateList[state.getContextID()] = vas = new osg::VertexArrayState(&state);
+    // OSG_NOTICE<<"Creating new osg::VertexArrayState "<< vas<<std::endl;
 
     if (_vertexArray.valid()) vas->assignVertexArrayDispatcher();
     if (_colorArray.valid()) vas->assignColorArrayDispatcher();
@@ -682,15 +689,15 @@ VertexArrayState* Geometry::createVertexArrayState(RenderInfo& renderInfo, bool
     if (!_texCoordList.empty()) vas->assignTexCoordArrayDispatcher(_texCoordList.size());
     if (!_vertexAttribList.empty()) vas->assignVertexAttribArrayDispatcher(_vertexAttribList.size());
 
-    if (usingVBOs && ds->getGeometryImplementation()==DisplaySettings::VERTEX_ARRAY_OBJECT)
+    if (state.useVertexArrayObject(_useVertexArrayObject))
     {
-        OSG_NOTICE<<"  Setup VertexArrayState to use VAO"<<std::endl;
+        // OSG_NOTICE<<"  Setup VertexArrayState to use VAO "<<vas<<std::endl;
 
         vas->generateVertexArrayObject();
     }
     else
     {
-        OSG_NOTICE<<"  Setup VertexArrayState to without using VAO"<<std::endl;
+        // OSG_NOTICE<<"  Setup VertexArrayState to without using VAO "<<vas<<std::endl;
     }
 
     return vas;
@@ -699,10 +706,7 @@ VertexArrayState* Geometry::createVertexArrayState(RenderInfo& renderInfo, bool
 void Geometry::compileGLObjects(RenderInfo& renderInfo) const
 {
     State& state = *renderInfo.getState();
-    bool useVertexArrays = _supportsVertexBufferObjects &&
-                           _useVertexBufferObjects &&
-                           renderInfo.getState()->isVertexBufferObjectSupported();
-    if (useVertexArrays)
+    if (renderInfo.getState()->useVertexBufferObject(_supportsVertexBufferObjects && _useVertexBufferObjects))
     {
         unsigned int contextID = state.getContextID();
         GLExtensions* extensions = state.get<GLExtensions>();
@@ -760,7 +764,7 @@ void Geometry::compileGLObjects(RenderInfo& renderInfo) const
         extensions->glBindBuffer(GL_ARRAY_BUFFER_ARB,0);
         extensions->glBindBuffer(GL_ELEMENT_ARRAY_BUFFER_ARB,0);
 
-        if (state.useVertexArrayObject() && !bufferObjects.empty())
+        if (state.useVertexArrayObject(_useVertexArrayObject) && !bufferObjects.empty())
         {
             VertexArrayState* vas = 0;
 
@@ -806,9 +810,7 @@ void Geometry::drawImplementation(RenderInfo& renderInfo) const
 
     drawPrimitivesImplementation(renderInfo);
 
-    bool useVertexArrayObject = _useVertexBufferObjects && state.useVertexArrayObject();
-    unsigned int contextID = renderInfo.getContextID();
-    if (!useVertexArrayObject || _vertexArrayStateList[contextID]->getRequiresSetArrays())
+    if (!state.useVertexArrayObject(_useVertexArrayObject) || state.getCurrentVertexArrayState()->getRequiresSetArrays())
     {
         // unbind the VBO's if any are used.
         state.unbindVertexBufferObject();
@@ -846,11 +848,9 @@ void Geometry::drawVertexArraysImplementation(RenderInfo& renderInfo) const
     arrayDispatchers.dispatch(osg::Array::BIND_OVERALL,0);
 
 
-    bool useVertexArrayObject = _useVertexBufferObjects &&  state.useVertexArrayObject();
-    unsigned int contextID = renderInfo.getContextID();
-    if (useVertexArrayObject)
+    if (state.useVertexArrayObject(_useVertexArrayObject))
     {
-        if (!_vertexArrayStateList[contextID]->getRequiresSetArrays()) return;
+        if (!state.getCurrentVertexArrayState()->getRequiresSetArrays()) return;
     }
 
     state.lazyDisablingOfVertexAttributes();
@@ -909,7 +909,7 @@ void Geometry::drawPrimitivesImplementation(RenderInfo& renderInfo) const
 {
     State& state = *renderInfo.getState();
     ArrayDispatchers& arrayDispatchers = state.getArrayDispatchers();
-    bool usingVertexBufferObjects = _useVertexBufferObjects && state.isVertexBufferObjectSupported();
+    bool usingVertexBufferObjects = state.useVertexBufferObject(_supportsVertexBufferObjects && _useVertexBufferObjects);
 
     bool bindPerPrimitiveSetActive = arrayDispatchers.active(osg::Array::BIND_PER_PRIMITIVE_SET);
     for(unsigned int primitiveSetNum=0; primitiveSetNum!=_primitives.size(); ++primitiveSetNum)
diff --git a/src/osg/PrimitiveSet.cpp b/src/osg/PrimitiveSet.cpp
index a654d5a92..987192906 100644
--- a/src/osg/PrimitiveSet.cpp
+++ b/src/osg/PrimitiveSet.cpp
@@ -196,15 +196,16 @@ void DrawElementsUByte::draw(State& state, bool useVertexBufferObjects) const
     if (useVertexBufferObjects)
     {
         GLBufferObject* ebo = getOrCreateGLBufferObject(state.getContextID());
-        state.getCurrentVertexArrayState()->bindElementBufferObject(ebo);
 
         if (ebo)
         {
+            state.getCurrentVertexArrayState()->bindElementBufferObject(ebo);
             if (_numInstances>=1) state.glDrawElementsInstanced(mode, size(), GL_UNSIGNED_BYTE, (const GLvoid *)(ebo->getOffset(getBufferIndex())), _numInstances);
             else glDrawElements(mode, size(), GL_UNSIGNED_BYTE, (const GLvoid *)(ebo->getOffset(getBufferIndex())));
         }
         else
         {
+            state.getCurrentVertexArrayState()->unbindElementBufferObject();
             if (_numInstances>=1) state.glDrawElementsInstanced(mode, size(), GL_UNSIGNED_BYTE, &front(), _numInstances);
             else glDrawElements(mode, size(), GL_UNSIGNED_BYTE, &front());
         }
@@ -257,15 +258,16 @@ void DrawElementsUShort::draw(State& state, bool useVertexBufferObjects) const
     if (useVertexBufferObjects)
     {
         GLBufferObject* ebo = getOrCreateGLBufferObject(state.getContextID());
-        state.getCurrentVertexArrayState()->bindElementBufferObject(ebo);
 
         if (ebo)
         {
+            state.getCurrentVertexArrayState()->bindElementBufferObject(ebo);
             if (_numInstances>=1) state.glDrawElementsInstanced(mode, size(), GL_UNSIGNED_SHORT, (const GLvoid *)(ebo->getOffset(getBufferIndex())), _numInstances);
             else glDrawElements(mode, size(), GL_UNSIGNED_SHORT, (const GLvoid *)(ebo->getOffset(getBufferIndex())));
         }
         else
         {
+            state.getCurrentVertexArrayState()->unbindElementBufferObject();
             if (_numInstances>=1) state.glDrawElementsInstanced(mode, size(), GL_UNSIGNED_SHORT, &front(), _numInstances);
             else glDrawElements(mode, size(), GL_UNSIGNED_SHORT, &front());
         }
@@ -317,15 +319,16 @@ void DrawElementsUInt::draw(State& state, bool useVertexBufferObjects) const
     if (useVertexBufferObjects)
     {
         GLBufferObject* ebo = getOrCreateGLBufferObject(state.getContextID());
-        state.getCurrentVertexArrayState()->bindElementBufferObject(ebo);
 
         if (ebo)
         {
+            state.getCurrentVertexArrayState()->bindElementBufferObject(ebo);
             if (_numInstances>=1) state.glDrawElementsInstanced(mode, size(), GL_UNSIGNED_INT, (const GLvoid *)(ebo->getOffset(getBufferIndex())), _numInstances);
             else glDrawElements(mode, size(), GL_UNSIGNED_INT, (const GLvoid *)(ebo->getOffset(getBufferIndex())));
         }
         else
         {
+            state.getCurrentVertexArrayState()->unbindElementBufferObject();
             if (_numInstances>=1) state.glDrawElementsInstanced(mode, size(), GL_UNSIGNED_INT, &front(), _numInstances);
             else glDrawElements(mode, size(), GL_UNSIGNED_INT, &front());
         }
diff --git a/src/osg/State.cpp b/src/osg/State.cpp
index 73f84c097..0ce9f2fae 100644
--- a/src/osg/State.cpp
+++ b/src/osg/State.cpp
@@ -96,7 +96,9 @@ State::State():
     _isFogCoordSupported = false;
     _isVertexBufferObjectSupported = false;
     _isVertexArrayObjectSupported = false;
-    _useVertexArrayObject = false;
+
+    _forceVertexBufferObject = false;
+    _forceVertexArrayObject = false;
 
     _lastAppliedProgramObject = 0;
 
@@ -176,7 +178,8 @@ void State::initializeExtensionProcs()
     _isVertexArrayObjectSupported = _glExtensions->isVAOSupported;
 
     const DisplaySettings* ds = getDisplaySettings() ? getDisplaySettings() : osg::DisplaySettings::instance();
-    _useVertexArrayObject = _isVertexArrayObjectSupported &&  (ds->getGeometryImplementation()==DisplaySettings::VERTEX_ARRAY_OBJECT);
+    _forceVertexArrayObject = _isVertexArrayObjectSupported && (ds->getVertexBufferHint()==DisplaySettings::VERTEX_ARRAY_OBJECT);
+    _forceVertexBufferObject = _forceVertexArrayObject || (_isVertexBufferObjectSupported && (ds->getVertexBufferHint()==DisplaySettings::VERTEX_BUFFER_OBJECT));
 
 
     // Set up up global VertexArrayState object
diff --git a/src/osg/VertexArrayState.cpp b/src/osg/VertexArrayState.cpp
index 7d09839b5..075127248 100644
--- a/src/osg/VertexArrayState.cpp
+++ b/src/osg/VertexArrayState.cpp
@@ -719,3 +719,9 @@ void VertexArrayState::setInterleavedArrays( osg::State& state, GLenum format, G
     dirtyAllVertexArrays();
 #endif
 }
+
+void VertexArrayState::dirty()
+{
+    setRequiresSetArrays(true);
+}
+