AnimationTimer and actual frame rate

[Michael Paus]

Yes, that's what I normally observe and when you increase the load on 
the graphics pipeline
this is eventually slowed down when a frame rate of 60FPS cannot be 
maintained anymore.

Now on my Mac I observe a very strange behavior under certain conditions 
where the visible
frame updates drop to something like 1FPS but the AnimationTimer is 
still running with
something like 30FPS. So, what I would like to know is whether such a 
behavior is normal according
to the design or whether this is a potential bug. I have not yet 
observed this behavior on Windows.

Michael

Am 03.01.17 um 15:30 schrieb Kevin Rushforth:
> A running AnimationTimer class will cause pulses to be scheduled 
> continuously, but they should still be limited to no more often than 
> 1/60 sec (unless you are overriding it with system properties).
>
> -- Kevin
>
>
> Markus KARG wrote:
>> Merry Christmas,
>>
>> my personal observation when performaning an EU-fundet power consumption study was that once an (even no-op implementation!) AnimationTimer was registered, the CPU load increased by several percent _permanently_ on our lab machine. In contrast, with key frame animation, the CPU load stayed at zero percent but showed scattered peaks. Unfortunately I cannot tell you the actual JavaFX-internal reason for sure, but I assume that AnimationTimer is called at maximum possible CPU speed (i. e. more or less an endless loop) while the animation classes update only once per _pulse_ (i e. more or less 60 FPS).
>>
>> It feels like (but this might be a false detection of mine; I did not check the source code) as the pure _registering_ of an AnimationTimer would enable JavaFX to actually run some JavaFX-internal code "undelayed", while _just_ using animation classes do not run that same code before the next _pulse_ (possible by using timer interrupts set to the next 1/60s).
>>
>> It would be great if the JavaFX team could confirm this difference between AnimationTimer and animation classes?
>>
>> -Markus
>>
>> -----Original Message-----
>> From: openjfx-dev [mailto:openjfx-dev-bounces at openjdk.java.net] On Behalf Of Michael Paus
>> Sent: Samstag, 24. Dezember 2016 10:21
>> To:openjfx-dev at openjdk.java.net
>> Subject: Re: AnimationTimer and actual frame rate
>>
>> Many thanks again.
>>
>> Am 23.12.16 um 18:18 schrieb Markus KARG:
>>    
>>> I assume it is OK for you to use internal APIs?
>>>      
>> Of course it is :-)
>>    
>>>    Then you could go with:
>>>
>>> com.sun.javafx.perf.PerformanceTracker.getSceneTracker(scene)
>>>
>>> and let a timer fire one per second to request tracker.getAverageFPS().
>>>      
>> I'll give that a try as soon as my family lets me.
>>    
>>> Beware not to use any AnimationTimer handlers, as it will reduce FPS, even if the handler method is short.
>>>      
>> Is the AnimationTimer handler more critical in this respect than any of the built-in animations?
>>    
>>> -Markus
>>>
>>> -----Original Message-----
>>> From: openjfx-dev [mailto:openjfx-dev-bounces at openjdk.java.net] On
>>> Behalf Of Michael Paus
>>> Sent: Freitag, 23. Dezember 2016 17:04
>>> To:openjfx-dev at openjdk.java.net
>>> Subject: Re: AnimationTimer and actual frame rate
>>>
>>> Thank you. That explains a lot of what I am observing but it also makes me wonder how you could effectively measure the actual frame rate because that's what you are normally interested in.
>>> Michael
>>>
>>> Am 23.12.16 um 09:15 schrieb Markus KARG:
>>>      
>>>> AnimationTimer is fired once per "planned" frame (i. e. running at maximum possible FPS), not per "actually rendered" frame. JavaFX contains a lot of optimizations. For example, a boolean property animated over time to switch from false to true will only imply a single modification, hence only one frame is actually rendered.
>>>> -Markus
>>>>
>>>> -----Original Message-----
>>>> From: openjfx-dev [mailto:openjfx-dev-bounces at openjdk.java.net] On
>>>> Behalf Of Michael Paus
>>>> Sent: Donnerstag, 22. Dezember 2016 17:29
>>>> To:openjfx-dev at openjdk.java.net
>>>> Subject: AnimationTimer and actual frame rate
>>>>
>>>> Hi all,
>>>>
>>>> for quite a while now I am observing a strange behavior when running
>>>> some
>>>>
>>>> JavaFX graphics tests. The scenario is very simple. I am running some
>>>> animation
>>>>
>>>> which puts some load onto the graphics engine and I am trying to
>>>> measure the
>>>>
>>>> frame rate via an instance of an AnimationTimer. When I increase the
>>>> load high
>>>>
>>>> enough I reach a point where the indicated frame rate is just 60FPS
>>>> or even a bit
>>>>
>>>> lower but the observed frame rate on screen has already dropped to
>>>> something
>>>>
>>>> like 1-2 FPS. So what I observe is that the AnimationTimer is running
>>>> much faster
>>>>
>>>> than the updates of the graphics. How can that be? Does anybody have
>>>> an explanation
>>>>
>>>> under which circumstances this can happen? Or is this behavior a bug which I should report?
>>>>
>>>> Just some puzzle for the boring Christmas holidays :-)
>>>>
>>>> Merry Christmas to all of you
>>>>
>>>> Michael
>>>>
>>>> PS: My system is a MacBook Pro with NVidia graphic card.
>>>>
>>>>
>>>>        
>>
>>
>>