vtkOpenGL/MesaImageActor classes are difficult to extend due to non-virtual methods.
This issue was created automatically from an original Mantis Issue. Further discussion may take place here.
Methods in vtkOpenGL/MesaImageActor are not declared as virtual, and as such are very inefficient to subclass. It would be easy to solve this problem if the methods shared by these two classes (Load, InternalRender, MakeDataSuitable) were declared as pure virtual methods in their base class, vtkImageActor.