[Interest] R: Qt3D FPS limits

[Nikos Chantziaras]

Using vsync as a frame rate limiter is not a good idea, because of 
different refresh rates between monitors. On a 144Hz monitor, you'd be 
running at 144FPS even if that's not actually wanted.

Or, you might want to run at half the refresh rate (like 30FPS on a 60Hz 
monitor.)

Vsync and frame limiting are two different, unrelated things.


On 23/03/18 10:29, Paul Lemire wrote:
> Qt3D relies on your GPU vsync settings. To reach the maximum number of 
> FPS, just disable vsync in your driver settings. If on the other hand 
> you want to reduce FPS, call setSwapInterval on the 
> QSurfaceFormat::defaultFormat and set it before starting your Qt3D 
> application with QSurfaceFormat::setDefaultFormat.
> 
> Paul
> 
> 
> On 03/21/2018 07:46 PM, Xavier Bigand wrote:
>> If you want to lower the limit you can simply add a pause in the 
>> rendering thread before the swap buffer based on a timer.
>> I don't really know how to do that with qt3d, but with qt quick there 
>> is some slot like onBeforeRendering and onAfterRendering in which you 
>> should be able to insert a FPS limiter.
>>
>> In a general way you have to be really careful when doing such things 
>> because it can add some jitters in the animations if the frame-rate 
>> isn't constant due to a lack of precision of the timers or conflicts 
>> with the vsync,...
>>
>>
>> 2018-03-21 17:58 GMT+01:00 Igor Mironchik <igor.mironchik at gmail.com 
>> <mailto:igor.mironchik at gmail.com>>:
>>
>>
>>
>>     On 21.03.2018 19 <tel:21.03.2018%2019>:39, Carlo Ferraresi wrote:
>>
>>         Hi,
>>         I also noticed that PFS seem limited to 60.
>>         I would like to know if there is a way to set this threshold
>>         since even 30 FPS are enough for my application.
>>
>>
>>     Agree, and I would like to have possibility to change the limit,
>>     and to have possibility to set the limit to infinity...
>>
>>
>>
>>         Regards,
>>         C.
>>
>>
>>         On : mercoledì 21 marzo 2018 12:02
>>
>>             A: Qt Project <interest at qt-project.org
>>             <mailto:interest at qt-project.org>>
>>             Oggetto: [Interest] Qt3D FPS limits
>>
>>             Hello,
>>
>>             Does Qt 3D limits FPS by 60? Or FPS is always as much as
>>             possible?
>>
>>             Thank you.
>>