[bug] [macOS] verticalSync problem since macOS13 (GLFW-inherited issue)

[artificiel]

macOS13 introduces jitter in the timing of update/draw cycle of GLFW apps glfw/glfw#2249. it has (at least) 2 concrete negative effects in OF as demontrated in #7752 (comment)

• sometimes the jitter pushes the draw() later than the actual frame cycle, stuttering/dropping a frame

• ofGetElapsedTimef() is not reliable to control phase-based animations requiring isochronous steps

until it is fixed within GLFW (seems hard) — or at OF-level by working around the Timer (as inspiration see the google deepmind workaround) , or by implementing a metal backend, or other — ofSetVerticalSync(false) and using ofSetFrameRate(nnn) is recommended. using macOS14 game mode in fullscreen also helps as seen in #7752 (comment).

the uneven timing issue can be worked around by using something like ofGetExpectedPaintTimef(), but that will not prevent dropped frames.

this issue will be updated as the GLFW and OF evolution affects the behaviour.

[danomatika]

Does this issue happen with both ofSetVerticalSync(true) and ofSetFrameRate(60)? I don't quite remember why, but I feel like there was an issue with vsync only and I added setting the frame rate as well.

[artificiel]

yes, adding the framerate is better top the point of things being mostly unnoticeable, if the CPU load is low and if you don't relay of ofGetElapsedTimef()

timing with vsync, frameRate(60), OF fullscreen:

timing without vsync, frameRate(60), OF fullscreen:

and to give good measure of what is achievable, timing native fullscreen with game mode and no vsync:

(more can be found here)

[dimitre]

I think ofSetFrameRate should be redesigned out of ofTimer.
Or maybe an alternative ofTimer using std::chrono exclusively.
I've made some experiments in measuring here:

• std::chrono for FPS setting  #7866

and some insights from Glenn Fiedler about fps https://gafferongames.com/post/fix_your_timestep/

[dimitre]

Framerate drift is merged and it is much more precise now.
VSync is doable now outside GLFW if we use a similar solution to this one:
google-deepmind/mujoco@2f0fb1e
It seems ok because OF project is already including CoreVideo framework

[danomatika]

Thanks for the work on this, all!