414
edits
Changes
Jump to navigation
Jump to search
Line 73:
Line 73: − + + + Line 79:
Line 81: − + + + + + + + + +
→Screen synchronization issue on 120 Hz screens
== Screen synchronization issue on 120 Hz screens ==
== Screen synchronization issue on 120 Hz screens ==
There is a serious synchronisation issue where the picture.present() method returns one frame too early. It can be detected by measuring the time between two consecutive present() calls returning:
There is a serious synchronisation issue where the picture.present() method returns one frame too early. It can be detected by measuring the time between two consecutive present() calls returning:
<code>
<pre>
wait_interval(220)
picture1.present()
picture1.present()
int t0 = clock.time();
int t0 = clock.time();
int t1 = clock.time();
int t1 = clock.time();
int dt = t1-t0;
int dt = t1-t0;
</code>
</pre>
One would expect ''picture1'' to be shown for 1 frame (1/120 s) and time ''dt'' to show this. Sometimes this is not the case. The image will be shown for one frame (1/120 s), but ''dt'' will be 2/120 s:
[[File:Timeline.svg|none|thumbnail]]
The fact that ''picture1'' is shown for only 1/120 s was confirmed with a light sensor connected to an oscilloscope.
The chance of this issue occurring is highly dependant on the waiting time