I'm trying to gauge how fast/slow glBufferData() is. I plan on allowing the user to modify the data. How carefull do I need to be about doing this? Can I blindly update all the buffers whenever something changes, or should I try to be selective, only updating the things that changed after all the updating has been done? It could make a difference if I want to give the user real-time feedback if they are modifying the mesh, or changing colors with a slider, etc.