0025133: TKOpenGl - Crash on closing a view containing presentations with capping

OpenGl_Element destruction and resource deallocation methods now accept
a pointer to OpenGl_Context instead of a handle to avoid double deletion
of the context.

samples/qt/VoxelDemo/src/VoxelClient_VisDrawer.cxx

@@ -42,7 +42,7 @@ public:
 
   void Render (const Handle(OpenGl_Workspace) &theWorkspace) const;
 
-  virtual void Release (const Handle(OpenGl_Context)& theContext)
+  virtual void Release (OpenGl_Context* theContext)
   {
     //
   }

src/OpenGl/OpenGl_AspectFace.cxx

@@ -387,11 +387,11 @@ void OpenGl_AspectFace::Render (const Handle(OpenGl_Workspace)& theWorkspace) co
 // function : Release
 // purpose  :
 // =======================================================================
-void OpenGl_AspectFace::Release (const Handle(OpenGl_Context)& theContext)
+void OpenGl_AspectFace::Release (OpenGl_Context* theContext)
 {
   if (!myResources.Texture.IsNull())
   {
-    if (!theContext.IsNull())
+    if (theContext)
     {
       if (myResources.TextureId.IsEmpty())
       {
@@ -409,7 +409,7 @@ void OpenGl_AspectFace::Release (const Handle(OpenGl_Context)& theContext)
   myResources.ResetTextureReadiness();
 
   if (!myResources.ShaderProgram.IsNull()
-   && !theContext.IsNull())
+   && theContext)
   {
     theContext->ShaderManager()->Unregister (myResources.ShaderProgramId,
                                              myResources.ShaderProgram);

src/OpenGl/OpenGl_AspectFace.hxx

@@ -212,7 +212,7 @@ public:
   }
 
   Standard_EXPORT virtual void Render  (const Handle(OpenGl_Workspace)& theWorkspace) const;
-  Standard_EXPORT virtual void Release (const Handle(OpenGl_Context)&   theContext);
+  Standard_EXPORT virtual void Release (OpenGl_Context* theContext);
 
 protected:
 

src/OpenGl/OpenGl_AspectLine.cxx

@@ -83,10 +83,10 @@ void OpenGl_AspectLine::Render (const Handle(OpenGl_Workspace) &theWorkspace) co
 // function : Release
 // purpose  :
 // =======================================================================
-void OpenGl_AspectLine::Release (const Handle(OpenGl_Context)& theContext)
+void OpenGl_AspectLine::Release (OpenGl_Context* theContext)
 {
   if (!myResources.ShaderProgram.IsNull()
-   && !theContext.IsNull())
+   && theContext)
   {
     theContext->ShaderManager()->Unregister (myResources.ShaderProgramId,
                                              myResources.ShaderProgram);

src/OpenGl/OpenGl_AspectLine.hxx

@@ -54,7 +54,7 @@ public:
   }
 
   Standard_EXPORT virtual void Render  (const Handle(OpenGl_Workspace)& theWorkspace) const;
-  Standard_EXPORT virtual void Release (const Handle(OpenGl_Context)&   theContext);
+  Standard_EXPORT virtual void Release (OpenGl_Context* theContext);
 
 protected:
 

src/OpenGl/OpenGl_AspectMarker.cxx

@@ -1505,11 +1505,11 @@ void OpenGl_AspectMarker::Render (const Handle(OpenGl_Workspace)& theWorkspace)
 // function : Release
 // purpose  :
 // =======================================================================
-void OpenGl_AspectMarker::Release (const Handle(OpenGl_Context)& theCtx)
+void OpenGl_AspectMarker::Release (OpenGl_Context* theCtx)
 {
   if (!myResources.Sprite.IsNull())
   {
-    if (!theCtx.IsNull())
+    if (theCtx)
     {
       if (myResources.SpriteKey.IsEmpty())
       {
@@ -1531,7 +1531,7 @@ void OpenGl_AspectMarker::Release (const Handle(OpenGl_Context)& theCtx)
   myResources.SpriteAKey.Clear();
   myResources.ResetSpriteReadiness();
 
-  if (!myResources.ShaderProgram.IsNull() && !theCtx.IsNull())
+  if (!myResources.ShaderProgram.IsNull() && theCtx)
   {
     theCtx->ShaderManager()->Unregister (myResources.ShaderProgramId,
                                          myResources.ShaderProgram);

src/OpenGl/OpenGl_AspectMarker.hxx

@@ -100,7 +100,7 @@ public:
   }
 
   Standard_EXPORT virtual void Render  (const Handle(OpenGl_Workspace)& theWorkspace) const;
-  Standard_EXPORT virtual void Release (const Handle(OpenGl_Context)&   theContext);
+  Standard_EXPORT virtual void Release (OpenGl_Context* theContext);
 
 protected: //! @name ordinary aspect properties
 

src/OpenGl/OpenGl_AspectText.cxx

@@ -101,10 +101,10 @@ void OpenGl_AspectText::Render (const Handle(OpenGl_Workspace)& theWorkspace) co
 // function : Release
 // purpose  :
 // =======================================================================
-void OpenGl_AspectText::Release (const Handle(OpenGl_Context)& theContext)
+void OpenGl_AspectText::Release (OpenGl_Context* theContext)
 {
   if (!myResources.ShaderProgram.IsNull()
-   && !theContext.IsNull())
+   && theContext)
   {
     theContext->ShaderManager()->Unregister (myResources.ShaderProgramId,
                                              myResources.ShaderProgram);

src/OpenGl/OpenGl_AspectText.hxx

@@ -130,7 +130,7 @@ public:
   }
 
   Standard_EXPORT virtual void Render  (const Handle(OpenGl_Workspace)& theWorkspace) const;
-  Standard_EXPORT virtual void Release (const Handle(OpenGl_Context)&   theContext);
+  Standard_EXPORT virtual void Release (OpenGl_Context* theContext);
 
 protected:
 

src/OpenGl/OpenGl_CappingPlaneResource.cxx

@@ -56,7 +56,7 @@ void OpenGl_CappingPlaneResource::Update (const Handle(OpenGl_Context)& theConte
 // function : Release
 // purpose  :
 // =======================================================================
-void OpenGl_CappingPlaneResource::Release (const OpenGl_Context* theContext)
+void OpenGl_CappingPlaneResource::Release (OpenGl_Context* theContext)
 {
   OpenGl_Element::Destroy (theContext, myAspect);
   myEquationMod = (unsigned int )-1;
@@ -83,7 +83,7 @@ void OpenGl_CappingPlaneResource::UpdateAspect (const Handle(OpenGl_Context)& th
   // no more used
   if (myAspect != NULL && aCappingAsp.IsNull())
   {
-    OpenGl_Element::Destroy (theContext, myAspect);
+    OpenGl_Element::Destroy (theContext.operator->(), myAspect);
     myAspectMod = myPlaneRoot->MCountAspect();
     return;
   }

src/OpenGl/OpenGl_CappingPlaneResource.hxx

@@ -50,7 +50,7 @@ public:
 
   //! Release associated OpenGl resources.
   //! @param theContext [in] the resource context.
-  Standard_EXPORT void Release (const OpenGl_Context* theContext);
+  Standard_EXPORT void Release (OpenGl_Context* theContext);
 
   //! @return aspect face for rendering capping surface.
   inline const OpenGl_AspectFace* AspectFace() const { return myAspect; }

src/OpenGl/OpenGl_Element.hxx

@@ -30,11 +30,17 @@ public:
   virtual void Render (const Handle(OpenGl_Workspace)& theWorkspace) const = 0;
 
   //! Release GPU resources.
-  virtual void Release (const Handle(OpenGl_Context)& theContext) = 0;
+  //! Pointer to the context is used because this method might be called
+  //! when the context is already being destroyed and usage of a handle
+  //! would be unsafe
+  virtual void Release (OpenGl_Context* theContext) = 0;
 
+  //! Pointer to the context is used because this method might be called
+  //! when the context is already being destroyed and usage of a handle
+  //! would be unsafe
   template <typename theResource_t>
-  static void Destroy (const Handle(OpenGl_Context)& theContext,
+  static void Destroy (OpenGl_Context* theContext,
-                       theResource_t*&               theElement)
+                       theResource_t*& theElement)
   {
     if (theElement == NULL)
     {

src/OpenGl/OpenGl_Flipper.cxx

@@ -53,7 +53,7 @@ OpenGl_Flipper::OpenGl_Flipper (const gp_Ax2& theReferenceSystem)
 // function : Release
 // purpose  :
 // =======================================================================
-void OpenGl_Flipper::Release (const Handle(OpenGl_Context)& )
+void OpenGl_Flipper::Release (OpenGl_Context*)
 {
   //
 }

src/OpenGl/OpenGl_Flipper.hxx

@@ -41,7 +41,7 @@ public:
   void SetOptions (const Standard_Boolean theIsEnabled) { myIsEnabled = theIsEnabled; }
 
   Standard_EXPORT virtual void Render (const Handle(OpenGl_Workspace)& theWorkspace) const;
-  Standard_EXPORT virtual void Release (const Handle(OpenGl_Context)&  theCtx);
+  Standard_EXPORT virtual void Release (OpenGl_Context* theCtx);
 
 public:
 

src/OpenGl/OpenGl_Font.cxx

@@ -54,7 +54,7 @@ OpenGl_Font::~OpenGl_Font()
 // function : Release
 // purpose  :
 // =======================================================================
-void OpenGl_Font::Release (const OpenGl_Context* theCtx)
+void OpenGl_Font::Release (OpenGl_Context* theCtx)
 {
   if (myTextures.IsEmpty())
   {

src/OpenGl/OpenGl_Font.hxx

@@ -57,7 +57,7 @@ public:
   Standard_EXPORT virtual ~OpenGl_Font();
 
   //! Destroy object - will release GPU memory if any
-  Standard_EXPORT virtual void Release (const OpenGl_Context* theCtx);
+  Standard_EXPORT virtual void Release (OpenGl_Context* theCtx);
 
   //! @return key of shared resource
   inline const TCollection_AsciiString& ResourceKey() const

src/OpenGl/OpenGl_FrameBuffer.cxx

@@ -108,7 +108,7 @@ Standard_Boolean OpenGl_FrameBuffer::Init (const Handle(OpenGl_Context)& theGlCo
 // function : Release
 // purpose  :
 // =======================================================================
-void OpenGl_FrameBuffer::Release (const OpenGl_Context* theGlCtx)
+void OpenGl_FrameBuffer::Release (OpenGl_Context* theGlCtx)
 {
   if (isValidFrameBuffer())
   {

src/OpenGl/OpenGl_FrameBuffer.hxx

@@ -41,7 +41,7 @@ public:
   Standard_EXPORT virtual ~OpenGl_FrameBuffer();
 
   //! Destroy object - will release GPU memory if any.
-  Standard_EXPORT virtual void Release (const OpenGl_Context* theGlCtx);
+  Standard_EXPORT virtual void Release (OpenGl_Context* theGlCtx);
 
   //! Textures width.
   GLsizei GetSizeX() const

src/OpenGl/OpenGl_GraduatedTrihedron.cxx

@@ -189,7 +189,7 @@ static void drawArrow(float x1, float y1, float z1,
 // function : Release
 // purpose  :
 // =======================================================================
-void OpenGl_GraduatedTrihedron::Release (const Handle(OpenGl_Context)& theCtx)
+void OpenGl_GraduatedTrihedron::Release (OpenGl_Context* theCtx)
 {
   myLabelX.Release (theCtx);
   myLabelY.Release (theCtx);

src/OpenGl/OpenGl_GraduatedTrihedron.hxx

@@ -37,7 +37,7 @@ public:
   OpenGl_GraduatedTrihedron (const Graphic3d_CGraduatedTrihedron& theData);
 
   virtual void Render  (const Handle(OpenGl_Workspace)& theWorkspace) const;
-  virtual void Release (const Handle(OpenGl_Context)&   theCtx);
+  virtual void Release (OpenGl_Context* theCtx);
 
 protected:
 

src/OpenGl/OpenGl_GraphicDriver_7.cxx

@@ -402,7 +402,7 @@ void OpenGl_GraphicDriver::RemoveView (const Graphic3d_CView& theCView)
       OpenGl_Structure* aStruct = aStructIt.ChangeValue();
       aStruct->ReleaseGlResources (aCtx);
     }
-    myTempText->Release (aCtx);
+    myTempText->Release (aCtx.operator->());
     myDeviceLostFlag = !myMapOfStructure.IsEmpty();
   }
 

src/OpenGl/OpenGl_Group.cxx

@@ -378,14 +378,14 @@ void OpenGl_Group::Release (const Handle(OpenGl_Context)& theGlCtx)
   while (myFirst != NULL)
   {
     OpenGl_ElementNode* aNext = myFirst->next;
-    OpenGl_Element::Destroy (theGlCtx, myFirst->elem);
+    OpenGl_Element::Destroy (theGlCtx.operator->(), myFirst->elem);
     delete myFirst;
     myFirst = aNext;
   }
   myLast = NULL;
 
-  OpenGl_Element::Destroy (theGlCtx, myAspectLine);
+  OpenGl_Element::Destroy (theGlCtx.operator->(), myAspectLine);
-  OpenGl_Element::Destroy (theGlCtx, myAspectFace);
+  OpenGl_Element::Destroy (theGlCtx.operator->(), myAspectFace);
-  OpenGl_Element::Destroy (theGlCtx, myAspectMarker);
+  OpenGl_Element::Destroy (theGlCtx.operator->(), myAspectMarker);
-  OpenGl_Element::Destroy (theGlCtx, myAspectText);
+  OpenGl_Element::Destroy (theGlCtx.operator->(), myAspectText);
 }

src/OpenGl/OpenGl_LineAttributes.cxx

@@ -517,7 +517,7 @@ OpenGl_LineAttributes::~OpenGl_LineAttributes()
 // function : Release
 // purpose  :
 // =======================================================================
-void OpenGl_LineAttributes::Release (const OpenGl_Context* theGlCtx)
+void OpenGl_LineAttributes::Release (OpenGl_Context* theGlCtx)
 {
   // Delete line styles
   if (myLinestyleBase != 0)

src/OpenGl/OpenGl_LineAttributes.hxx

@@ -33,7 +33,7 @@ public:
   virtual ~OpenGl_LineAttributes();
 
   void Init (const Handle(OpenGl_Context)& theGlCtx);
-  virtual void Release (const OpenGl_Context* theGlCtx);
+  virtual void Release (OpenGl_Context* theGlCtx);
 
   void SetTypeOfLine (const Aspect_TypeOfLine theType) const;
 

src/OpenGl/OpenGl_PointSprite.cxx

@@ -49,7 +49,7 @@ OpenGl_PointSprite::~OpenGl_PointSprite()
 // function : Release
 // purpose  :
 // =======================================================================
-void OpenGl_PointSprite::Release (const OpenGl_Context* theGlCtx)
+void OpenGl_PointSprite::Release (OpenGl_Context* theGlCtx)
 {
   if (myBitmapList != 0)
   {

src/OpenGl/OpenGl_PointSprite.hxx

@@ -32,7 +32,7 @@ public:
   Standard_EXPORT virtual ~OpenGl_PointSprite();
 
   //! Destroy object - will release GPU memory if any.
-  Standard_EXPORT virtual void Release (const OpenGl_Context* theCtx);
+  Standard_EXPORT virtual void Release (OpenGl_Context* theCtx);
 
   //! @return true if this is display list bitmap
   inline Standard_Boolean IsDisplayList() const

src/OpenGl/OpenGl_PrimitiveArray.cxx

@@ -778,11 +778,11 @@ OpenGl_PrimitiveArray::~OpenGl_PrimitiveArray()
 // function : Release
 // purpose  :
 // =======================================================================
-void OpenGl_PrimitiveArray::Release (const Handle(OpenGl_Context)& theContext)
+void OpenGl_PrimitiveArray::Release (OpenGl_Context* theContext)
 {
   if (!myVboIndices.IsNull())
   {
-    if (!theContext.IsNull())
+    if (theContext)
     {
       theContext->DelayedRelease (myVboIndices);
     }
@@ -790,7 +790,7 @@ void OpenGl_PrimitiveArray::Release (const Handle(OpenGl_Context)& theContext)
   }
   if (!myVboAttribs.IsNull())
   {
-    if (!theContext.IsNull())
+    if (theContext)
     {
       theContext->DelayedRelease (myVboAttribs);
     }

src/OpenGl/OpenGl_PrimitiveArray.hxx

@@ -50,7 +50,7 @@ public:
   //! Render primitives to the window
   virtual void Render  (const Handle(OpenGl_Workspace)& theWorkspace) const;
 
-  virtual void Release (const Handle(OpenGl_Context)&   theContext);
+  virtual void Release (OpenGl_Context* theContext);
 
   //! @return primitive type (GL_LINES, GL_TRIANGLES and others)
   GLint DrawMode() const { return myDrawMode; }

src/OpenGl/OpenGl_Resource.hxx

@@ -45,7 +45,7 @@ public:
   //! Notice that implementation should be SAFE for several consecutive calls
   //! (thus should invalidate internal structures / ids to avoid multiple-free errors).
   //! @param theGlCtx - bound GL context, shouldn't be NULL.
-  Standard_EXPORT virtual void Release (const OpenGl_Context* theGlCtx) = 0;
+  Standard_EXPORT virtual void Release (OpenGl_Context* theGlCtx) = 0;
 
 private:
 

src/OpenGl/OpenGl_ShaderObject.cxx

@@ -125,7 +125,7 @@ Standard_Boolean OpenGl_ShaderObject::Create (const Handle(OpenGl_Context)& theC
 // function : Release
 // purpose  : Destroys shader object
 // =======================================================================
-void OpenGl_ShaderObject::Release (const OpenGl_Context* theCtx)
+void OpenGl_ShaderObject::Release (OpenGl_Context* theCtx)
 {
   if (myShaderID == NO_SHADER)
   {

src/OpenGl/OpenGl_ShaderObject.hxx

@@ -57,7 +57,7 @@ public:
   Standard_EXPORT Standard_Boolean Create (const Handle(OpenGl_Context)& theCtx);
 
   //! Destroys shader object.
-  Standard_EXPORT virtual void Release (const OpenGl_Context* theCtx);
+  Standard_EXPORT virtual void Release (OpenGl_Context* theCtx);
 
   //! Returns type of shader object.
   GLenum Type() const { return myType; }

src/OpenGl/OpenGl_ShaderProgram.cxx

@@ -1245,7 +1245,7 @@ Standard_Boolean OpenGl_ShaderProgram::Create (const Handle(OpenGl_Context)& the
 // function : Release
 // purpose  : Destroys shader program
 // =======================================================================
-void OpenGl_ShaderProgram::Release (const OpenGl_Context* theCtx)
+void OpenGl_ShaderProgram::Release (OpenGl_Context* theCtx)
 {
   if (myProgramID == NO_PROGRAM)
   {

src/OpenGl/OpenGl_ShaderProgram.hxx

@@ -157,7 +157,7 @@ public:
   Standard_EXPORT Standard_Boolean Create (const Handle(OpenGl_Context)& theCtx);
 
   //! Destroys shader program.
-  Standard_EXPORT virtual void Release (const OpenGl_Context* theCtx);
+  Standard_EXPORT virtual void Release (OpenGl_Context* theCtx);
 
   //! Attaches shader object to the program object.
   Standard_EXPORT Standard_Boolean AttachShader (const Handle(OpenGl_Context)&      theCtx,

src/OpenGl/OpenGl_StencilTest.cxx

@@ -42,7 +42,7 @@ void OpenGl_StencilTest::Render (const Handle(OpenGl_Workspace)&) const
 // function : Release
 // purpose  :
 // =======================================================================
-void OpenGl_StencilTest::Release (const Handle(OpenGl_Context)&)
+void OpenGl_StencilTest::Release (OpenGl_Context*)
 {
   //
 }

src/OpenGl/OpenGl_StencilTest.hxx

@@ -28,7 +28,7 @@ public:
   //! Render primitives to the window
   virtual void Render  (const Handle(OpenGl_Workspace)& theWorkspace) const;
 
-  virtual void Release (const Handle(OpenGl_Context)& theContext);
+  virtual void Release (OpenGl_Context* theContext);
 
   void SetOptions (const Standard_Boolean theIsEnabled);
 

src/OpenGl/OpenGl_Structure.cxx

@@ -93,7 +93,7 @@ public:
   }
 
   //! Release graphical resources
-  virtual void Release (const Handle(OpenGl_Context)& )
+  virtual void Release (OpenGl_Context*)
   {
     //
   }
@@ -818,10 +818,10 @@ void OpenGl_Structure::Release (const Handle(OpenGl_Context)& theGlCtx)
 {
   // Release groups
   Clear (theGlCtx);
-  OpenGl_Element::Destroy (theGlCtx, myAspectLine);
+  OpenGl_Element::Destroy (theGlCtx.operator->(), myAspectLine);
-  OpenGl_Element::Destroy (theGlCtx, myAspectFace);
+  OpenGl_Element::Destroy (theGlCtx.operator->(), myAspectFace);
-  OpenGl_Element::Destroy (theGlCtx, myAspectMarker);
+  OpenGl_Element::Destroy (theGlCtx.operator->(), myAspectMarker);
-  OpenGl_Element::Destroy (theGlCtx, myAspectText);
+  OpenGl_Element::Destroy (theGlCtx.operator->(), myAspectText);
   clearHighlightColor (theGlCtx);
 
   // Remove from connected list of ancestor
@@ -840,23 +840,23 @@ void OpenGl_Structure::ReleaseGlResources (const Handle(OpenGl_Context)& theGlCt
   }
   if (myAspectLine != NULL)
   {
-    myAspectLine->Release (theGlCtx);
+    myAspectLine->Release (theGlCtx.operator->());
   }
   if (myAspectFace != NULL)
   {
-    myAspectFace->Release (theGlCtx);
+    myAspectFace->Release (theGlCtx.operator->());
   }
   if (myAspectMarker != NULL)
   {
-    myAspectMarker->Release (theGlCtx);
+    myAspectMarker->Release (theGlCtx.operator->());
   }
   if (myAspectText != NULL)
   {
-    myAspectText->Release (theGlCtx);
+    myAspectText->Release (theGlCtx.operator->());
   }
   if (!myHighlightBox.IsNull())
   {
-    myHighlightBox->Release (theGlCtx);
+    myHighlightBox->Release (theGlCtx.operator->());
   }
 }
 

src/OpenGl/OpenGl_Text.cxx

@@ -192,7 +192,7 @@ void OpenGl_Text::SetFontSize (const Handle(OpenGl_Context)& theCtx,
 {
   if (myParams.Height != theFontSize)
   {
-    Release (theCtx);
+    Release (theCtx.operator->());
   }
   myParams.Height = theFontSize;
 }
@@ -205,7 +205,7 @@ void OpenGl_Text::Init (const Handle(OpenGl_Context)& theCtx,
                         const Standard_Utf8Char*      theText,
                         const OpenGl_Vec3&            thePoint)
 {
-  releaseVbos (theCtx);
+  releaseVbos (theCtx.operator->());
   myIs2d   = false;
   myPoint  = thePoint;
   myString.FromUnicode (theText);
@@ -222,11 +222,11 @@ void OpenGl_Text::Init (const Handle(OpenGl_Context)& theCtx,
 {
   if (myParams.Height != theParams.Height)
   {
-    Release (theCtx);
+    Release (theCtx.operator->());
   }
   else
   {
-    releaseVbos (theCtx);
+    releaseVbos (theCtx.operator->());
   }
   myIs2d   = false;
   myParams = theParams;
@@ -245,11 +245,11 @@ void OpenGl_Text::Init (const Handle(OpenGl_Context)&     theCtx,
 {
   if (myParams.Height != theParams.Height)
   {
-    Release (theCtx);
+    Release (theCtx.operator->());
   }
   else
   {
-    releaseVbos (theCtx);
+    releaseVbos (theCtx.operator->());
   }
   myIs2d       = true;
   myParams     = theParams;
@@ -271,14 +271,14 @@ OpenGl_Text::~OpenGl_Text()
 // function : releaseVbos
 // purpose  :
 // =======================================================================
-void OpenGl_Text::releaseVbos (const Handle(OpenGl_Context)& theCtx)
+void OpenGl_Text::releaseVbos (OpenGl_Context* theCtx)
 {
   for (Standard_Integer anIter = 0; anIter < myVertsVbo.Length(); ++anIter)
   {
     Handle(OpenGl_VertexBuffer)& aVerts = myVertsVbo.ChangeValue (anIter);
     Handle(OpenGl_VertexBuffer)& aTCrds = myTCrdsVbo.ChangeValue (anIter);
 
-    if (!theCtx.IsNull())
+    if (theCtx)
     {
       theCtx->DelayedRelease (aVerts);
       theCtx->DelayedRelease (aTCrds);
@@ -297,7 +297,7 @@ void OpenGl_Text::releaseVbos (const Handle(OpenGl_Context)& theCtx)
 // function : Release
 // purpose  :
 // =======================================================================
-void OpenGl_Text::Release (const Handle(OpenGl_Context)& theCtx)
+void OpenGl_Text::Release (OpenGl_Context* theCtx)
 {
   releaseVbos (theCtx);
   if (!myFont.IsNull())
@@ -305,7 +305,8 @@ void OpenGl_Text::Release (const Handle(OpenGl_Context)& theCtx)
     Handle(OpenGl_Context) aCtx = theCtx;
     const TCollection_AsciiString aKey = myFont->ResourceKey();
     myFont.Nullify();
-    aCtx->ReleaseResource (aKey, Standard_True);
+    if (aCtx)
+      aCtx->ReleaseResource (aKey, Standard_True);
   }
 }
 
@@ -637,7 +638,7 @@ void OpenGl_Text::render (const Handle(OpenGl_PrinterContext)& thePrintCtx,
    && !myFont->ResourceKey().IsEqual (aFontKey))
   {
     // font changed
-    const_cast<OpenGl_Text* > (this)->Release (theCtx);
+    const_cast<OpenGl_Text* > (this)->Release (theCtx.operator->());
   }
 
   if (myFont.IsNull())

src/OpenGl/OpenGl_Text.hxx

@@ -59,7 +59,7 @@ public:
                                     const Standard_Integer        theFontSize);
 
   Standard_EXPORT virtual void Render  (const Handle(OpenGl_Workspace)& theWorkspace) const;
-  Standard_EXPORT virtual void Release (const Handle(OpenGl_Context)&   theContext);
+  Standard_EXPORT virtual void Release (OpenGl_Context* theContext);
 
 public: //! @name methods for compatibility with layers
 
@@ -107,7 +107,7 @@ protected:
 private:
 
   //! Release cached VBO resources
-  void releaseVbos (const Handle(OpenGl_Context)& theCtx);
+  void releaseVbos (OpenGl_Context* theCtx);
 
   //! Setup matrix.
   void setupMatrix (const Handle(OpenGl_PrinterContext)& thePrintCtx,

src/OpenGl/OpenGl_Texture.cxx

@@ -115,7 +115,7 @@ bool OpenGl_Texture::Create (const Handle(OpenGl_Context)& )
 // function : Release
 // purpose  :
 // =======================================================================
-void OpenGl_Texture::Release (const OpenGl_Context* theGlCtx)
+void OpenGl_Texture::Release (OpenGl_Context* theGlCtx)
 {
   if (myTextureId == NO_TEXTURE)
   {

src/OpenGl/OpenGl_Texture.hxx

@@ -206,7 +206,7 @@ public:
   Standard_EXPORT bool Create (const Handle(OpenGl_Context)& theCtx);
 
   //! Destroy object - will release GPU memory if any.
-  Standard_EXPORT virtual void Release (const OpenGl_Context* theCtx);
+  Standard_EXPORT virtual void Release (OpenGl_Context* theCtx);
 
   //! Bind this Texture to specified unit.
   Standard_EXPORT void Bind (const Handle(OpenGl_Context)& theCtx,

src/OpenGl/OpenGl_TextureBufferArb.cxx

@@ -54,7 +54,7 @@ GLenum OpenGl_TextureBufferArb::GetTarget() const
 // function : Release
 // purpose  :
 // =======================================================================
-void OpenGl_TextureBufferArb::Release (const OpenGl_Context* theGlCtx)
+void OpenGl_TextureBufferArb::Release (OpenGl_Context* theGlCtx)
 {
   if (myTextureId != NO_TEXTURE)
   {

src/OpenGl/OpenGl_TextureBufferArb.hxx

@@ -56,7 +56,7 @@ public:
   }
 
   //! Destroy object - will release GPU memory if any.
-  Standard_EXPORT virtual void Release (const OpenGl_Context* theGlCtx);
+  Standard_EXPORT virtual void Release (OpenGl_Context* theGlCtx);
 
   //! Creates VBO and Texture names (ids) if not yet generated.
   //! Data should be initialized by another method.

src/OpenGl/OpenGl_Trihedron.cxx

@@ -640,7 +640,7 @@ OpenGl_Trihedron::~OpenGl_Trihedron()
 // function : Release
 // purpose  :
 // =======================================================================
-void OpenGl_Trihedron::Release (const Handle(OpenGl_Context)& theCtx)
+void OpenGl_Trihedron::Release (OpenGl_Context* theCtx)
 {
   myLabelX.Release (theCtx);
   myLabelY.Release (theCtx);

src/OpenGl/OpenGl_Trihedron.hxx

@@ -43,7 +43,7 @@ public:
                     const Standard_Boolean              theAsWireframe);
 
   virtual void Render  (const Handle(OpenGl_Workspace)& theWorkspace) const;
-  virtual void Release (const Handle(OpenGl_Context)&   theCtx);
+  virtual void Release (OpenGl_Context* theCtx);
 
 protected:
 

src/OpenGl/OpenGl_VertexBuffer.cxx

@@ -69,7 +69,7 @@ bool OpenGl_VertexBuffer::Create (const Handle(OpenGl_Context)& theGlCtx)
 // function : Release
 // purpose  :
 // =======================================================================
-void OpenGl_VertexBuffer::Release (const OpenGl_Context* theGlCtx)
+void OpenGl_VertexBuffer::Release (OpenGl_Context* theGlCtx)
 {
   if (myBufferId == NO_BUFFER)
   {

src/OpenGl/OpenGl_VertexBuffer.hxx

@@ -70,7 +70,7 @@ public:
   Standard_EXPORT bool Create (const Handle(OpenGl_Context)& theGlCtx);
 
   //! Destroy object - will release GPU memory if any.
-  Standard_EXPORT virtual void Release (const OpenGl_Context* theGlCtx);
+  Standard_EXPORT virtual void Release (OpenGl_Context* theGlCtx);
 
   //! Bind this VBO.
   Standard_EXPORT void Bind (const Handle(OpenGl_Context)& theGlCtx) const;

src/OpenGl/OpenGl_View.cxx

@@ -104,8 +104,8 @@ OpenGl_View::~OpenGl_View ()
 
 void OpenGl_View::ReleaseGlResources (const Handle(OpenGl_Context)& theCtx)
 {
-  OpenGl_Element::Destroy (theCtx, myTrihedron);
+  OpenGl_Element::Destroy (theCtx.operator->(), myTrihedron);
-  OpenGl_Element::Destroy (theCtx, myGraduatedTrihedron);
+  OpenGl_Element::Destroy (theCtx.operator->(), myGraduatedTrihedron);
 
   if (!myTextureEnv.IsNull())
   {
@@ -233,7 +233,7 @@ void OpenGl_View::TriedronDisplay (const Handle(OpenGl_Context)&       theCtx,
                                    const Standard_Real                 theScale,
                                    const Standard_Boolean              theAsWireframe)
 {
-  OpenGl_Element::Destroy (theCtx, myTrihedron);
+  OpenGl_Element::Destroy (theCtx.operator->(), myTrihedron);
   myTrihedron = new OpenGl_Trihedron (thePosition, theColor, theScale, theAsWireframe);
 }
 
@@ -241,7 +241,7 @@ void OpenGl_View::TriedronDisplay (const Handle(OpenGl_Context)&       theCtx,
 
 void OpenGl_View::TriedronErase (const Handle(OpenGl_Context)& theCtx)
 {
-  OpenGl_Element::Destroy (theCtx, myTrihedron);
+  OpenGl_Element::Destroy (theCtx.operator->(), myTrihedron);
 }
 
 /*----------------------------------------------------------------------*/
@@ -249,7 +249,7 @@ void OpenGl_View::TriedronErase (const Handle(OpenGl_Context)& theCtx)
 void OpenGl_View::GraduatedTrihedronDisplay (const Handle(OpenGl_Context)&        theCtx,
                                              const Graphic3d_CGraduatedTrihedron& theData)
 {
-  OpenGl_Element::Destroy (theCtx, myGraduatedTrihedron);
+  OpenGl_Element::Destroy (theCtx.operator->(), myGraduatedTrihedron);
   myGraduatedTrihedron = new OpenGl_GraduatedTrihedron (theData);
 }
 
@@ -257,7 +257,7 @@ void OpenGl_View::GraduatedTrihedronDisplay (const Handle(OpenGl_Context)&
 
 void OpenGl_View::GraduatedTrihedronErase (const Handle(OpenGl_Context)& theCtx)
 {
-  OpenGl_Element::Destroy (theCtx, myGraduatedTrihedron);
+  OpenGl_Element::Destroy (theCtx.operator->(), myGraduatedTrihedron);
 }
 
 /*----------------------------------------------------------------------*/

src/ViewerTest/ViewerTest_OpenGlCommands.cxx

@@ -103,7 +103,7 @@ public:
         myIObj->Render(theWorkspace);
     }
 
-    virtual void Release (const Handle(OpenGl_Context)&)
+    virtual void Release (OpenGl_Context*)
     {
       //
     }