clutter/frame-clock: Comment presentation time skip

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1707>
This commit is contained in:
Ivan Molodetskikh 2020-11-27 18:16:33 +03:00 committed by Marge Bot
parent ed93a11de6
commit 01b30ff9e4

View File

@ -280,7 +280,20 @@ calculate_next_update_time_us (ClutterFrameClock *frame_clock,
next_presentation_time_us = logical_clock_phase_us + hw_clock_offset_us;
}
/* Skip one interval if we got an early presented event. */
/*
* Skip one interval if we got an early presented event.
*
* last frame this was last_presentation_time
* / frame_clock->next_presentation_time_us
* / /
* |---|-o-----|-x----->
* | \
* \ next_presentation_time_us is thus right after the last one
* but got an unexpected early presentation
* \_/
* time_since_last_next_presentation_time_us
*
*/
last_next_presentation_time_us = frame_clock->next_presentation_time_us;
time_since_last_next_presentation_time_us =
next_presentation_time_us - last_next_presentation_time_us;