Framerate drops to ~45fps on iOS ... sometimes

[kleibrook]

I was just playing around with a trivial multi-touch test script in MOAI when I noticed some odd behaviour apparently related to screen orientation. I'm displaying the performance and step values from MOAISim on the screen and while i was poking and swiping, i accidentally rotated the device, and the framerate dropped to about 44fps as reported by MOAISim, which is also consistent with the noticably jerkier touch events I was getting at that time.

If I rotated the device back to the original orientation, fps went back up to 60 and input became smoother again. I could understand if this was an optimization sort of thing, in that certain orientations maybe need more work for doing the rotation, however... I reproduced the problem several times, and the orientations in which the framerate drops may be different every time. If I just keep rotating the device, eventually one or more orientations will begin rendering at 44, and then I can rotate back to a 60fps orientation and it's all good again... back and forth. Sometimes they're all good, others any one or more of the 4 orientations might exhibit the slowdown.

Any thoughts/ideas?

iPhone 4 running iOS 5.1.1 and using the latest packaged build of moai sdk

[dana]

That is strange, I will look into this and try to reproduce it. Thanks for reporting it.

[Charles]

I have been experiencing something very similar. Also on iPod Touch 4th generation.

Have a simple app with a 512x512 MOAI Tile Grid and a map imported from the Tiled Editor. The app allows you to drag the camera across the map using a single touch.

When I open the app on the iPod for the first time, performance is good ( approx 60fps )
I hit the home button on the iPod Touch to "minimize" my app.
I open the app again. performance is bad ( approx 15 fps or less)

Closing and then re-opening the app causes bad performance about 50% of the time

[dana]

I was able to reproduce the bug where the fps was dropping when rotated to landscape mode, and I filed a bug for that.

Charles, I couldn't reproduce your bug with exiting to the home screen and re-opening the app. Would you be able to send me a code sample that does it?

[Charles]

Yes what's the best way to send it?

If you have an assembla.com account, I can add you to the team.

[dana]

How about email? My email is dana@ziplinegames.com

[kleibrook]

I was able to reproduce the bug where the fps was dropping when rotated to landscape mode, and I filed a bug for that.

Great, thanks

[Charles]

Hey Dana, I emailed you the code. Did you get a change to look at it?

[adam]

We weren't able to reproduce the backgrounding and resuming issue here. I'll be looking into the fps drop on rotation soon.

[Charles]

The frame-rate issue I was experiencing in build #56 seems to be working perfectly in #66. Hooray!