Apps set to Screen time are strongly constrained by their behavior.
If the screen time starts while the app is running, the nature of the app causes problems in operation.
Normally, the setting screen is called by the following code, but I do not know how to call Screen Time.
UIApplication.sharedApplication().openURL(settingsURL)
Do you know how to do that? Or tell me if there is another way around it.
I have created a spriteKit game and have a problem with performance issues.
Problem:
FPS gets stuck at 40.0
How and when does it happen
1. I have a pause function in my game by just using view!.scene?.paused = true Sometimes when I hit the home button, launch another app, then go back to the game the FPS gets 'stuck' at 40 and doesnt climb back up to 60.0. (Sometimes it does)
2. I have a 'sharing' Facebook and Twitter icon where when you tap on it you can post/share/tweet something on your account. This icon can be seen in the pause menu. After posting or returning back to the game FPS gets stuck at 40 FPS (And again, sometimes it does climb back up to 60. Sometimes it does not)
3. To clarify, this doesnt happen mid-game. This only happens if I minimize the app, launch the Facebook/Twitter icons, during reminder pop-ups.
Temporary fix
There is a temporary fix to this, which is to minimize the app and then launching it again. However, I wouldnt want my users to experience this at all. If possible Id like to eliminate this problem altogether.
What I have tried so far to fix this
1.Ive tried running this on instruments (time Profiler) but nothing really caught my eye. Thought I have to say I am quite new with instruments.
2. There is a similar question here but for him disabling UIKit items fixed it for him, and I dont have any of that.
3. I initially thought it was a SKShapeNode issue so I changed my sprites to SKSpriteNode. No help here either.
4. I have tried without the USB cable attached to the phone and tried running it using the Run button on XCode. No difference.
5. Ive tried rebooting device and laptop. Didnt help.
6. Tried this on multiple devices. Same issue.
Stats?
Game typically starts out at 20 nodes and 5 draws and can go up to 60 nodes 6 draws but it will actually still run smooth as long as I dont initiate any of the triggering methods mentioned above.
I have spent alot of time trying to find a solution for this. Changing codes and streamlining it. Googling it. I really need help on this one. I would really appreciate some help.
Update for comment #1
For you first inquiry
1) I have a SKSpriteNode as the pause button during gameplay for the user to pause the game if he wants to.
2) I have func applicationWillResignActive(application: UIApplication) {} in my AppDelegate.swift file that triggers a GameScene.swift function that changes a flag from true to false so that I know when the user goes out and come back in again. And I have my update block searching for that flag. If it is true, display the pause menu. However, this 40FPS issue happened before I added this whole pause/unpause thing. (The 40 FPS issue is what made me create the pause menu for this) (I know too in the latest ver. of swift that it will auto-pause when the app is minimized and unpause when I bring it back up.)
I'm making a game for iOS where you mostly drag big objects across the screen. When I run the game on an actual iPad/iPhone for a while (continuously dragging the object in circles across the screen) every 5 minutes or so the dragged object goes all stuttery for about 10-30 seconds. Then, it goes back to moving silky-smooth.
Visually, it looks like the game's frame rate dropped to 15 fps for a while, but in actual fact it's running at rock-solid 60 fps all the time. However, I noticed that the only thing that doesn't move smoothly is the dragged object, while the rest of the game is all running perfectly smooth.
This led me to believe that the stuttering is related to the touch input in iOS. So I started looking at touchesMoved, and saw that it's normally called every 16 milliseconds (so touch input runs at 60 fps). So far so good.
Then I noticed that when the object starts stuttering, touchesMoved starts being called at weird time intervals, fluctuating wildly between 8 milliseconds and 50 milliseconds.
So while the touchscreen is in this weird state, sometimes touchesMoved will get called just 8 milliseconds after the previous call, and sometimes it won't get called until 50 ms after the previous call. Of course, this makes the dragged object look all choppy because its position is updated at irregular intervals.
Do you have any idea what could be causing touchesMoved to stop being called at regular intervals, as it normally does?
Bonus:
-Whenever I tilt the screen to force the screen orientation to change, roughly 70% of the time the touchscreen goes into the aforementioned state where touchesMoved starts being called irregularly. Then after 10-20 seconds it goes back to normal and everything looks smooth again.
-I've tried this on two iPads and two iPhones, with iOS 6 and 7, and the issue appears in all of these devices.
-An OpenGLES view is used to display the graphics. It syncs to the display refresh rate using CADisplayLink.
-The Xcode project I'm using to test this has been generated by the unity3d game development tool, but I've found several non-unity games where the same issue appears. this appears to be a system-wide problem. note I'm measuring the timings in objective-c using CFAbsoluteTimeGetCurrent, completely outside unity.
This is not a bug in Unity.
Something inside the OS is getting into a bad state and the touch-drag messages stop flowing smoothly. Sometimes you'll get multiple updates in a frame and sometimes you'll get none.
The issue does not happen on iPhone4 or below, or if the game is running at 30Hz frame rate.
I experienced this bug while using an in-house engine I'd written while working at a previous company. It first manifest itself after upgrading the UI system of a scrabble genre game, where you drag the tiles about on the screen. This was utterly bizarre, and I was never able to pin down the exact reproduction steps, but they seem to be timing related, somehow.
It can also be seen on Angry Birds (unless they've fixed it by now), and a variety of other games on the market, basically anything with touch-drag scrolling or movement. For Angry Birds, just go into a level and start scrolling sideways. Most of the time it'll be silky smooth, but maybe 1 in 10 times, it'll be clunky. Re-start the app and try again.
A workaround is to drop the input update frequency to 30Hz for a few frames. This jolts the internals of the OS somehow and gives it time to straighten itself out, so when you crank it back up to 60Hz, it runs smoothly again.
Do that whenever you detect that the bad state has been entered.
I've also run into this. I can verify that it's a bug in Unity 4.3.x.
My 4.2.x builds process touches on device at 60Hz with TouchPhase.Moved on every frame.
My 4.3.x builds get 20-40Hz with TouchPhase.Stationary being emitted on dropped frames.
TestFlight history saved my sanity here.
Don't forget to file a bug with UT.
It's a real disaster. Sometimes it's lag and sometimes it's really smooth. It lags even when GPU and CPU utilization are below 10%. it's not Unity bug. I'm using cocos2d v3.
If someone found a cure, please post it!
I've been running into this as well. My current hypothesis which I still have to verify is that if you ask for a given frame rate (eg. 60fps), but your actually achieved frame rate is less than that (eg. 45fps) that this causes a timing/race condition issue between Unity requesting inputs from iOS at a higher frame rate than it actually is running at. However, if you set it to 30fps (at least in my UNity 5.2 tests with iOS 9.1) then you get a solid 30Hz of input. When I disabled a chunk of my game and it was running at a very solid 60fps, then I would consistently get 60Hz of input from the touch screen. This is what I have for now, but I have to prove this in a simple project which I haven't had time to do yet. Hope this helps someone else.
I found a potential solution to this problem here: https://forums.developer.apple.com/thread/62315 (posting here because it took me a lot of research to stumble across that link whereas this StackOverflow question was the first Google result).
To follow up on this, I got a resonse on my bug report to Apple. This
is the response:
"As long as you don't cause any display updates the screen stays in
low power and therefore 30hz mode, which in turn also keeps the event
input stream down at 30 hz. A workaround is to actually cause a
display update on each received move, even if it is just a one pixel
move of a view if input is needed while no explicit screen update will
be triggered."
In my application, using a GLKView, I set its
preferredFramesPerSecond to 60. Occasionally, my input rate would
randomly drop to 30hz. The response from Apple doesn't fully explain
why this would happen, but apparently the expected method of handling
this is to call display() directly from touchesMoved() while dragging.
I've subclassed GLKView and I set preferredFramesPerSecond to 60. On
touchesBegan(), I set isPaused=true, and start calling display()
within touchesMoved(). On touchesEnd(), I set isPaused=false. Doing
this, I'm no longer having any issues - the app is more performant
than it's ever been.
Apple's example TouchCanvas.xcodeproj does all drawing from within
touchesMoved() as well, so I guess this is the intended way to handle
this.
As far as I can tell, your best bet to achieve a smooth look may be to interpolate between touch events, rather than immediately mapping your objects to your touch position.
tl;dr: It seems just having a CADisplayLink causing any OpenGL context or Metal device to draw at 60fps can cause this.
I was repro'ing this on my iPhone 7 Plus w/ iOS 10.2.1.
I made a small sample simple app with a CADisplayLink with preferredFramesPerSecond = 60, and tried the following rendering approaches:
GLKView w/ display()
CAEAGLLayer, used as prescribed by Apple at WWDC (opaque, sole layer, fullscreen, nothing drawn above it)
MTLDevice
In each case, the render method would only clear the screen, not try drawing anything else.
In each case, I saw the input rate problem.
The following "tricks" also seemed to do nothing, when called inside touchesMoved:
Calling glkView.setNeedsDisplay() (with enableSetNeedsDisplay set to true)
Moving some other view
Calling glkView.display() (actually, seems like it can raise your input rate to 40 events per second. But it doesn't look any better, as far as I can tell, and seems wrong to do, so I wouldn't recommend it.)
I gave up, after running all these tests. Instead, I interpolate my object between the touch positions instead. So it's what I'd recommend, too.
But I figured I'd include my research here in case somebody else takes a stab at it and finds a better solution.
I have a timer in my app, and I want it to appear to be running while my app is on the background. I'd like that if the user presses the home button when the timer shows, for instant "01:11:11" and then goes back to the app and it becomes visible to him 10 minutes later, to see the timer as "01:01:11", however I get a split second where it shows the last state when the app went to the background ("01:11:11") before it starts updating from the correct time.
I assumed that I could correct this by updating the state of my timer in "applicationDidBecomeActive" and it did work on my simulator in Xcode but not on my Ipad.
I'm using cocos2d for my drawing and this is what I'm doing in my applicationDidBecomeActive:
CCScene *s=[director_ runningScene];
GameLayer *l=[(GameLayer*)[s getChildByTag:GAME_LAYER_TAG];
if (l!=nil) [l myUpdate];
I don't think it's relevant to the problem though because myUpdate does get called but I still have that split second glitch on my Ipad, as if it starts back from its last state no matter what.
In apples clock app, in applicationDidEnterBackground it hides the timer text, so that when the app comes into the foreground you see a blank UI for the split second where your app is loading the new timer data in the UI. Also, you may want to call some of your applicationDidBecomeActive code in applicationWillEnterForeground, which is called first. But keep in mind, applicationWillEnterForeground is not called when the app first launches.
There will always be a delay between when your app comes into the foreground, and when the UI updates. Theres no way to fix that, so you might as well use what apple uses to get around the issue.
Well I tried to hide my UI in both applicationWillResignActive and applicationDidEnterBackground. Since applicationWillResignActive is called first and before going into preview (double click on HOME) it causes a "not so pretty" preview but I thought at least it would solve my original problem. It didn't (not, on my IPad). It looks like the system takes the screen shot even before applicationWillResignActive.
I checked the timer in the official clock app and I see the clock is updating even when the app is in the background (in preview), so they "cheat" anyway...
When I've used painting/drawing apps, I never notice a delay between pressing my finger and being able to see something drawn on the display. However with my app, the initial touches are received very slowly. The second and third and fourth gestures are received a 60 per second, but the first gesture is maybe 2-3 touch events per second. Furthermore if I let the app sit idle for a 10 seconds, the same delay happens again. It's as though iOS forgets that the app needs attention, or the device (iPad 3, iOS 5.1.1) goes into a kind of sleep where the display is on but touch response slows.
UPDATE: If I put the iPad 3 to sleep/lock by closing the display and leave it for 10 seconds, then open the display, the initial sluggish touches response happens every time.
UPDATE: This problem is not occurring on my iPad 1 running iOS 5.1.1. Even when I bring the iPad 1 back from sleep/unlock, there is no delay.
I haven't really worked with this kind of thing before, but I recall reading somewhere about using a UIBezierPath to create a drawing app. You could try to use that. According to this question, it's faster:
Why is UIBezierPath faster than Core Graphics path?
A tutorial is here: http://soulwithmobiletechnology.blogspot.com/2011/05/uibezierpath-tutorial-for-iphone-sdk-40.html