How to get the point in time of (last) vertical retrace under Python?

Question

Hi there,

I am using Pygame to pageflip different stimuli on the screen. The problem is that pygame's flip function, although syncing the flip to the vertical retrace, does not tell me when the retrace was. Does anyone know of a way to get this information (preferably platform independent) in Python?

Regards, fladd

Answer 1

Just poll for the time immediately after the flip call, if that one syncs to the vertical retrace.

Answer 2

Uhm, no, that is the problem. The flip function itself does not wait for the vsync to happen. It just contiunes after it told the hardware that it should flip whenevert the next refresh occurs. But this time I don't know. The time after the flip call just tells me how long it too the flip function to report to the hardware, not how long the hardware then eventually took. This is exactly the mystery I am trying to solve.

fladd