cocos2d for iPhone

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

1. 

   bsharp42
   Member

   Trying to remove AtlasSprites in AtlasSpriteManager and the following code seems to throw an error message. How do I remove AtlasSprites from the scene/layer (I won't be needed these sprites so I need them gone from memory as well) ??

   AtlasSpriteManager *manager = (AtlasSpriteManager*) [self getChildByTag:0];

   for (AtlasSprite *bomb in manager.children)
   {
   [bomb stopAllActions];
   [manager removeChild:bomb cleanup:YES];
   }

   Posted 2 years ago #
2. 

   Codemattic
   Moderator

   You cannot remove an object from an array while you are iterating through that array. Its a big p.i.t.a.

   "code seems to throw an error message."

   in the future when you are asking about the error - include the error message - as opposed to just saying "there was an error"

   Posted 2 years ago #
3. 

   QcMat
   Member

   With a regular array, I remove stuff while iterating through it and just decrement my i & count values in consequence.

   Posted 2 years ago #
4. 

   Codemattic
   Moderator

   "With a regular array"

   By regular I assume you mean a c-based array, yes that will work. But sadly not for a Cocoa NSMutableArray.

   Maybe:

   NSArray * tempArray = [NSArray arrayWithArray:manager.children];
   for (AtlasSprite *bomb in tempArray)
   {
    [bomb stopAllActions];
    [manager removeChild:bomb cleanup:YES];
   }

   Posted 2 years ago #
5. 

   QcMat
   Member

   With a NSMutableArray and a for loop. I use the objectAtIndex method and use removeObject. when I remove an object, I decrement my i and count variables and the loop continues to the next object.

   Posted 2 years ago #
6. 

   Codemattic
   Moderator

   Ahhh, very nice! However, Im not sure about speed. NSMutableArray is (I believe) a linked list internally. So its very quick to find objectAtIndex:0, while its slower to access objectAtIndex:1000. What Cocoa does is cache the last objectAtIndex, so if you call objectAtIndex with the next index it can still find it very fast (it doesnt have to start at the front again). But Im not sure if that cache is kept between doing a removeObjectAtIndex.

   I wish Cocoa's mutable container classes had some of the features of C++ STL classes that let you mark objects for deletion and remove them in one call.

   Posted 2 years ago #
7. 

   bsharp42
   Member

   The following worked !

   AtlasSpriteManager *manager = (AtlasSpriteManager*) [self getChildByTag:0];

   for (int i=[manager.children count]-1; i>=0; i--)
   {
   AtlasSprite *bomb = [manager.children objectAtIndex:i];

   [bomb stopAllActions];
   [manager removeChildAtIndex:i cleanup:YES];
   }

   Posted 2 years ago #
8. 

   Codemattic
   Moderator

   good tip. What about using:

   for (AtlasSprite *bomb in manager.children)
   {
     [bomb stopAllActions];
   }
   [manager removeAllChildrenWithCleanup:YES];

   Posted 2 years ago #
9. 

   QcMat
   Member

   I can't speak on speed since I'm pretty new to Objective-C. All I know is that my method works pretty well. I started doing it with PHP and was happy to see that it worked well here too.

   If done with multiple nested FORs, the use of break; becomes necessary so you don't skip any verifications with the next object and create errors.

   Posted 2 years ago #

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