cocos2d for iPhone

A fast, easy to use, free, and community supported 2D game engine

1. 

   peters
   Member

   Hello,

   We have a cocos2d racing game where the player is constantly holding the gas button pressed while racing. The player is usually also quickly pressing and releasing buttons on the other side of the screen. The game is played in landscape mode with your thumbs on the buttons. This works fine on all devices except the iPhone 5 where the gas sometimes is released by itself without any reason. We've confirmed this with many of our users.

   When testing ourselves on iPhone 5 we see that somtimes we get a touchesCancelled event for all touches, even though a finger is still down on the gas button. It can take 15 minutes of play to reproduce this bug. We've done a number of checks to see what could cause this cancelled event but haven't found anything yet.

   We've also created a minimal test case with the same button layout as our game but COULD NOT reproduce the bug there. This test did not use cocos2d though.

   We've made sure that no UIGestureRecognizers are added to the UIView. We do a check each frame to see if any UIGestureRecognizers are present. We've also made sure that no screen rotations occur during play. No such events happen and autorotation is disabled.

   We're using GameCenter and we do also have a UIWebView loaded in the background which is only shown when the the user clicks certain buttons in the menus. We do also use Appirater, Twitter and the Facebook SDK.

   We're using cocos2d version 0.99.4, but we've inserted our code to test the touches in EAGLView so we're basically getting the touch events directly from iOS. We log all touch events in EAGLView and there we see the unwanted "touches cancelled" that seem to happen for no reason.

   Does anybody else have the same kind of problem and do you have any suggestions of possible causes to look for?
   Can this be a hardware / iOS problem that we need to work around?

   We're currently investigating if any other UIView could be popping up and disappearing within one frame. Maybe it wouldn't be noticeable visually, but enough to cancels all events for the game's EAGLView.

   Any suggestions/workarounds are welcome!

   Best regards,
   Peter

   Posted 3 months ago #
2. 

   Birkemose
   Administrator

   I recon you are implementing multitouch?
   One major pitfall, which will often work, but will eventually lead to grief - if dealing with multitouch - is if you retain touches. Only weak pointers are allowed.

   Only guessing of course, but this would probably be an issue which would be more severe on faster devices.

   Posted 3 months ago #
3. 

   peters
   Member

   Thanks for the reply.

   We do use multitouch, but we never retain any UITouch objects. We do also check that "multipleTouchEnabled" is true for the UIView each frame, just in case we would by mistake disable the multitouch.

   Posted 3 months ago #
4. 

   jordo
   Member

   Same issues here... Holding area on right side of the iPhone 5, and rapidly touching the left area results sometimes in ccTouchesCancelled happening.. Only can replicate the issue on the Iphone 5.

   Posted 2 months ago #
5. 

   jordo
   Member

   Only seems to happen along the bottom of the screen... Maybe it has something to do with the new "finger rejection" detection apple seems to be implementing? Our (press-and-hold) button is on the bottom-right of devices in landscape mode.

   http://pocketnow.com/2012/11/02/finger-rejection-ios-601

   Posted 2 months ago #
6. 

   peters
   Member

   jordo:
   I'm glad to see that we're not the only ones having these problems. Have you done something to resolve it? Any workarounds or other insights you can share?

   We've somewhat made the problem less painful by letting the gas get stuck on a "touch cancelled" instead of being released. Players will usually hold the gas pressed all the time so some people might not even notice the bug.

   Posted 2 months ago #
7. 

   peters
   Member

   We've asked this question also on the iOS developer forum:
   https://devforums.apple.com/thread/180778

   That post includes a minimal test case to show the touch cancelled issue.

   Posted 2 months ago #
8. 

   jordo
   Member

   Hey Peters,

   That's exactly what we did.. Our 'go' button simply gets stuck on when it doesn't receive the touches ended... Not exactly ideal.

   I've spent all day yesterday trying to find a work-around, but couldn't find anything.

   Posted 2 months ago #
9. 

   peters
   Member

   I think we'll solve it by moving our buttons a little farther up on the screen. We do only see this problem on iPhone 5, so I'm thinking we'll only move the buttons for that device.

   Posted 2 months ago #

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