I’m using the commonly proposed leapfrogging PBO transfer technique, and I’m doing it on a separate thread (+ context) for each movie I play. Then each screen has it’s own context and accesses those frames.
My question is, how can I tell when the PBO transfer is complete? I know that if I access the texture while the transfer is still happening (on Linux, at least) then I can see an incomplete texture. So is there a way to ‘touch’ the pixels on the PBO that will force the transfer to complete, but not take any more time than needed to do that? I know it will block but I will only be doing this after the PBO has had some transfer time already.