由于SimpleAudioEngine，应用程序因背景而崩溃

Question

So I׳m trying to play some effects in my Cocos2D game using SimpleAudioEngine , but after I have added them my app crashes when it goes to background (multitasked). I searched for this problem in the internet but all the solutions that I found didn't work for me. What I did find out is that this problem happens because my app is somehow trying to play sounds when backgrounded.

In console it shows me (which is the same error I found other people had):

sgx error (background gpu access not permitted):

And another thing, when I run my app on the simulator, or even on my device while debugging carefully (going line-by-line with XCode while the app is running) this doesn't happen.

Answer 1

I just had this issue. I resolved it by having a bool to check if the app is running or in background that I set to true when the app goes to foreground ( applicationWillEnterForeground ) and that I set to false when the app goes to background ( applicationDidEnterbackground ) . So using the bool you can tell if the app is in the background and if it is, I just exit out of drawView function in EAGLView (thus not doing any graphics rendering which was causing the error).

I am a very dodge programmer but that method has worked for me and I hope it works for someone else. I did not need to unload and reload my sounds or anything and my app now has Multitasking XD

Answer 2

I just resolved this issue on my end. Here's what was wrong in my case and, from what I can tell from the other answers and comments on this page, many other people's case as well:

By default, when I started my project, CCDirector::sharedDirector()->pause(); and CCDirector::sharedDirector()->resume(); were both being called twice, once by (void)applicationWillResignActive:(UIApplication *) and (void)applicationDidBecomeActive:(UIApplication *) respectively in AppController.mm , and once by AppDelegate::applicationDidEnterBackground() and AppDelegate::applicationWillEnterForeground() respectively in AppDelegate.cpp .

Make absolutely sure that these methods are only being called once, in AppController.mm. In AppDelegate.cpp, instead make sure that you are calling CCDirector::sharedDirector()->stopAnimation(); in place of CCDirector::sharedDirector()->pause(); and CCDirector::sharedDirector()->startAnimation(); in place of CCDirector::sharedDirector()->resume(); .

Hope that's helpful to anyone else stuck in this crappy situation!

Answer 3

I was experiencing this, on about 25% of the occasions that my application re-entered the foreground. Like you, when I removed the sounds, the problem went away. That is how I came across your question here.

I may have found a solution to this. I have made what appears to be an unrelated change, but the problem seems to have gone away. Now, when my app enters the background, I invalidate my main scheduled timer. When my app re-enters the foreground, I then re-schedule the timer (after reloading my sounds, which I completely shut down on entering background).

So far, the problem has not come back. I would be interested to know if this helps.

Answer 4

I had the same issue in my application and spent some 4 hours to find out. Going background was OK the first time, but crash application the second time. With a short error message related to OpenGL. I had the same questions: how audio can crash graphics. But it wasn't a question of audio, but a question of notifications...

I discovered that going foreground was creating 2 timers in my custom level meter class. I had registered UIApplicationWillEnterForegroundNotification and UIApplicationWillResignActiveNotification . Then, going background invalidated only one, since I registered only on notification... That was it!

One need's count its notifications!

Answer 5

Are you sure it's related to audio? "background gpu access" sounds like it's using OpenGL.