3D touch seems really cool and I wanted to see how it would work in a musical context. I was reading a bit about 3D touch and it seems like the force property almost always reads as 0 when a touch begins (touchesBegan method).
How do I get a usable force when a touch begins because even if I'm pressing with maximum "force" I'm still getting that initial 0? I was thinking about just approximating a value within a time frame but that would involve me moving the touch. I just want a usable force upon the first touch.
Thanks!
Unfortunately this is impossible.
Every touch starts as a contact with no force at all, as soon as the user's finger makes contact (or even near-contact) with the screen. The force only starts to build as the user's finger is compressed against the screen.
The only way for touchesBegan: to report any force at all would be for it to delay artificially for a certain number of milliseconds before reporting a touch, to allow the force to build up. This would destroy the interactivity of all iOS applications; and Apple put a huge amount of work into delivering a touch the instant it is detected.
I am working on an app for a physical boardgames I have produced in the past. Everything is working fine (for now). But the app "freezes up" when the code for the computer "thinking" kicks in.
This is understandable, the computer needs time to make it's turn.
My question is. Is there any way I can simultaneously set an animation to run (like a progress icon), while the computer continues to "think" over it's turn?
Thank You.
You can't make something like a progress bar which indicates exactly when the computer will finish 'thinking' exactly because the computer does not know when it will be done.
However, you can create an animation that will run as long as the computer 'thinks'.
In your Gameplay file in Spritebuilder, create the animation that you want shown while the user waits. Chain this animation timeline to itself. Let's call the default timeline animation 'default' and the 'computer is thinking' timeline animation 'think'.
Inside the method you use to start the computer's turn, add a line of code that warns cocos2d to run the 'think' animation sequence; it would also be good to make any user interaction with the game impossible at this time (example below is given in Swift):
animationManager.runAnimationsForSequenceNamed("think")
self.userInteractionEnabled = false
Since the 'think' timeline was chained to itself, it will run in an infinite loop, only stopping once cocos2d receives an instruction to break that timeline and start executing another one, so, just inside the method you execute once the computer's turn is over, add these two lines in order to stop the 'think' animation from running and to enable user interaction once again:
animationManager.runAnimationsForSequenceNamed("default")
self.userInteractionEnabled = true
Not knowing where you are building your actual game in, using different threads is the way to go. What are you building your game in? Which language, framework, platform?
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 am working on a research project that involves user interaction with an iPod. The application runs for approximately 10 hours, and I need to record the following information:
1) How many times was the screen touched?
2) For each touch, where was it touched? (Inside the button vs.outside)
3) What time was it touched? This would preferably be the time of day, but I can do back-calculations if this is not possible.
This information needs to be saved, and exported to a file that can be manipulated in Matlab, Igor, Excel,etc.
The application itself is very simple. A button in the middle of the screen flashes while playing a sound. When a touch event occurs inside the button, the flashing and sound stop for 30 seconds.
My questions is similar to this one from 2010 How to record all of the user's touches in iPhone app. The asker, however, did not provide the details for how he accomplished this, and I'm afraid I need a little more guidance than is given.
I'd be grateful for some advice, or if you could point me to the appropriate resources. I would especially appreciate it if you could also let me know the general area where the code should go. I'm still getting the hang of objective-C.
I am developing a tic tac toe game for iOS and I am using a combination of UIButtons and UIImageViews to allow for user interaction and to display the moves made. My problem is that the buttons continue to accept user input before the cpu makes it's move, which breaks my game logic. I have made several attempts to toggle the userInteractionEnabled property, but I have only been able to turn it off. The engine that gets everything started in the game is my buttonPressed method. I also toggle the userInteractionEnabled property within this method and therein lies my problem: How do I re-enable the property after disabling user interaction? Is there a method that is called in between events that I can overwrite?
I have searched the web and I have searched through the developer documentation provided by Apple and I found information on the touchesBegan and touchesEnded methods. However, from what I understand, those methods need to be explicitly called which brings me back to my original problem of not being able to call those functions without the user's interaction.
If anyone can help, I would greatly appreciate it! I have been racking my brain over this for the past couple of weeks and I am just not seeing a solution.
I'd think that for a game like tic-tac-toe, calculating the countermove should be so fast that it can be done immediately in response to the first button press. If you're doing something complicated to calculate the next move, like kicking off a thread, you might want to reconsider that.
Let's say, though, that your game is something like chess or go, where coming up with a countermove might take a bit longer. Your view controller should have a method to make a move for the current player, let's call it -makeMove:. Your -buttonPressed action should call that method to make a move for the user. In response, -makeMove: should update the state of the game, switch the current player to the next player. If the new current player is the computer, it should then disable the controls and start the process of calculating the next move. Let's imagine that's done by invoking some NSOperation, so that coming up with the next move is an asynchronous task. Once the operation has come up with a move, it should again invoke -makeMove: (by calling -performSelectorOnMainThread:), which will again update the game state and the current player. This time, though, it should see that the new current player is not the computer, and so it should re-enable the controls.