From 01b30ff9e4406eb2c48af3f145e08990e3dcaa55 Mon Sep 17 00:00:00 2001 From: Ivan Molodetskikh Date: Fri, 27 Nov 2020 18:16:33 +0300 Subject: [PATCH] clutter/frame-clock: Comment presentation time skip Part-of: --- clutter/clutter/clutter-frame-clock.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/clutter/clutter/clutter-frame-clock.c b/clutter/clutter/clutter-frame-clock.c index 6a32ea3d7..2f617d0a5 100644 --- a/clutter/clutter/clutter-frame-clock.c +++ b/clutter/clutter/clutter-frame-clock.c @@ -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;