cocos2d for iPhone

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

1. 

   ksjogo
   Member

   Hi,
   I am used to be a GNU/Linux & PHP programmer but now I have an Iphone project.
   I have a game scene needing to load some numbers from the internet. If I directly send messages to my InternetUtils Class the interface will be unresponsible until an answer.(is this normal behaviour?) So I want to send a message to a internet thread, changing one label after receiving the data.
   I pass the scene to the thread and if the thread changes the string, the label acts unexpected, it becomes a white box.

   Shorted Code:
   GameScene
   

   ...
   [NSThread detachNewThreadSelector:@selector(calculateLabel:) toTarget:[InternetUtils class] withObject:self];

   Thread:
   

   @implementation InternetUtils
   +(void)calculateLabel:(GuessScene*)scene{
   	id p =[NSAutoreleasePool new];
   	bestWord = @"builded from more code";
   	[scene.GuessingWord setString:bestWord];
   	[p release];
   }
   
   @end

   Does someone know what is wrong with this code?
   And do I need to add special steps to end the thread?

   Generally: Are there any greater examples/guidelines about the organisation of the code? Should be game logic added to scenes or other objects?

   Cheers
   jogo

   Posted 1 year ago #
2. 

   CJ
   Moderator

   The reason you get a whitebox is because you cannot change anything with openGL in a background thread without first getting a context share group (which is demonstrated in the asynchronous loading in CCTextureCache). It is however probably needlessly complex for what you are trying to do.

   I would make it so that your thread does things in a more isolated way. If you can just get your thread to build up the string you want, and then when it's ready do something like this to change the label back in the main thread:
   

   //Your scene or whatever
   - (void) getNewWordFromInternet
   {
       NSInvocation *invocation = [NSInvocation invocationWithMethodSignature:[[self class] instanceMethodSignatureForSelector:@selector(gotNewWordFromInternet:)]];
       [invocation setTarget:self];
       [[InternetUtils sharedInstance] getNewWord:invocation];
   }
   
   - (void) gotNewWordFromInternet:(NSString *)aWord
   {
       [GuessingWord setString:aWord];
   }
   
   //Internet utils class:
   
   - (void) getNewWord:(NSInvocation *)invocation
   {
       [self performSelectorInBackground:@selector(getNewWordInBackground:) withObject:invocation];
   }
   
   - (void) getNewWordInBackground:(NSInvocation *)invocation
   {
       NSAutoReleasePool *pool = [NSAutoReleasePool new];
       NSString *bestWord = [your method to build up your string goes here];
       [invocation setArgument:bestWord atIndex:0];
       [self performSelectorOnMainThread:@selector(gotNewWord:) withObject:invocation waitUntilDone:YES];
       [pool drain];
   }
   
   - (void) gotNewWord:(NSInvocation *)invocation
   {
       [invocation invoke];
   }

   Posted 1 year ago #
3. 

   cyruschoi
   Member

   Sorry, I would like to know, is it about threading, simular to NSThread way?
   Also, what is InternetUtils?

   Is it guessingWord is the CClabel?

   Posted 1 year ago #
4. 

   adik
   Member

   Thank you CJ for your explanation of the issue. I was frustrated past 2 days, because I couldn't figure it out. Now I know! YES!!! :)

   Posted 11 months ago #

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