More minor fixes

Rendering/OpenGL2/vtkOpenGLRenderWindow.cxx

@@ -170,6 +170,7 @@ void vtkOpenGLRenderWindow::ReleaseGraphicsResources()
       vtkErrorMacro("Leaked for texture object: " << const_cast<vtkTextureObject *>(found->first));
       }
     }
+  this->Initialized = false;
 }
 
 // ----------------------------------------------------------------------------
@@ -1889,6 +1890,7 @@ void vtkOpenGLRenderWindow::SaveGLState()
   // For now just query the active texture unit
   if (this->Initialized)
     {
+    this->MakeCurrent();
     glGetIntegerv(GL_ACTIVE_TEXTURE, &this->GLStateIntegers["GL_ACTIVE_TEXTURE"]);
 
     // GetTextureUnitManager() will create a new texture unit

Rendering/VolumeOpenGL2/vtkOpenGLProjectedTetrahedraMapper.cxx

@@ -536,9 +536,6 @@ void vtkOpenGLProjectedTetrahedraMapper::ProjectTetrahedra(vtkRenderer *renderer
 
   // after mucking about with FBO bindings be sure
   // we're saving the default fbo attributes/blend function
-  glPushAttrib(GL_COLOR_BUFFER_BIT);
-  vtkOpenGLCheckErrorMacro("failed at glPushAttrib");
-
   this->AllocateFBOResources(renderer);
 
   if (this->UseFloatingPointFrameBuffer
@@ -1123,7 +1120,6 @@ void vtkOpenGLProjectedTetrahedraMapper::ProjectTetrahedra(vtkRenderer *renderer
     }
 
   // Restore the blend function.
-  glPopAttrib();
   vtkOpenGLCheckErrorMacro("failed at glPopAttrib");
 
   glDepthMask(GL_TRUE);