cocos2d for iPhone

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

1. 

   MisterX
   Member

   I have spend several hours trying to figure out how to dynamically create a class instance within a "for loop", including searching google and this forum. I want to create class instances along with several other things within this particular for loop. I want to avoid doing the following which repeats all the code over and over again, only changing the class instance name to be created:

   Ball* ballClassInstance0 = [[[Ball alloc] init] autorelease];
   // several other program steps following the class instance creation 
   
   Ball* ballClassInstance1 = [[[Ball alloc] init] autorelease];
   // several other program steps following the class instance creation
   
   Ball* ballClassInstance2 = [[[Ball alloc] init] autorelease];
   // several other program steps following the class instance creation
   
   Ball* ballClassInstance3 = [[[Ball alloc] init] autorelease];
   // several other program steps following the class instance creation

   I want to do something like this instead, but cannot figure out the syntax to do it..

   for (int i = 0; i < kNumBalls; i++) { 
   
   Ball* [NSString stringWithFormat:@"ballInstance%d", i] = [[[Ball alloc] init] autorelease];
   
   // several other program steps following the class instance creation only given once and not repeated.
   
   }

   Can anyone please show what the syntax is to dynamically replace the "name" of the class instance to be created?

   Posted 11 months ago #
2. 

   RelicaGames
   Member

   You don't need to replace the name of the object being created. You would just do:
   

   for (int i = 0; i < kNumBalls; i++) {
       Ball* ballClassInstance = [[[Ball alloc] init] autorelease];
       [self addChild:ballInstance];
       //etc
   }

   Posted 11 months ago #
3. 

   ImpresionesWeb
   Member

   If you want to control all the balls so you can do something with them after that you can assign them tags as in:

   #define kBallTags 200;
   ...
   for (int i = 0; i < kNumBalls; i++) {
       Ball* ballClassInstance = [[[Ball alloc] init] autorelease];
       ballClassInstance.tag=i+kBallTags;
       [self addChild:ballInstance];
       //etc
   }

   and get them later so:

   Ball* ballClassInstance =(Ball*)[self getChildByTag:kBallTags+3];

   Posted 11 months ago #
4. 

   Angry Panda
   Member

   Don't forget to add you instance to the parent layer: [self addChild:ballInstance]

   Posted 11 months ago #
5. 

   MisterX
   Member

   Thanks for the replies.

   Yes I need to be able to address all the instances individually or in some cases they could be addressed sequentially as they were created. I will try these suggestions out..

   I'm trying to work out a methodology for creating object instances that have a corresponding CCSprite object associated with them.

   For example I might have a "ball" class that needs to contain 5 ball objects, and each of those 5 ball object are associated with a unique CCSprite. Say a CCSprite of a Baseball, Basketball, Soccerball, Football, Softball (5 textures all within the same SpriteSheet).

   In another case, I might have a different "ball" class that contain 20 ball object, all of which use the same Soccerball, CCSprite texture.

   I have read about using an "initwithimage" method within the ball class, but I have a situation where I cannot just add a non-CCSprite node to my GameScene class layer. The GameScene class layer has background art CCSprites that are batched (in a SpriteBatchNode) and on DIFFERENT Z Layers. I need to be able to insert my ball objects at specific Z Depths between the different backdrop art images.

   The only way to do that, that I can figure out, is to add the ball objects as children to the GameScene batch node. A batch node will only accept CCSprites as children, it will not accept non-CCSprite class instance objects as children. Apparently, a batch node cannot be assigned as a child to another batch node either. You cannot nest batch nodes.

   Therefore, if I create a ball instance using "initwithimage", that ball instance becomes a CCNode and cannot be added to a SpriteBatchNode (I get compiler errors stating this).

   If the backdrop images are NOT BATCHED, and even if the ball Sprites are batched before creating instances with "initwithimage", the frame rate is unacceptably slow.. If I can draw the balls and backdrop images, in one batch, the frame rate only drops to about 58 or 59 fps at worst case.

   I have tried to implement Steffan Itterhiem's "Bullet and Enemy class" type structures and they fail to work for my application. His methodology assumes you have a background layer and a UI Layer and your just sandwiching your game sprites in between those two layers by creating nodes to insert as new layers into the GameScene. My sprites need to intermingle between the Z depths of my background layer elements. If I draw each background image Sprite in a separate call (by NOT batching them and allowing his methodology to work) my frame rate becomes too slow and game sprite movement gets jerky and jittery.

   Since I want to be able to individually manipulate ball objects within a GameScene class, but add them to a batch node withing the game scene class, I am trying to create a set of CCSprite objects, and then create a set of Ball instance objects (which contain logic code) which would control the CCSprite objects which are drawn to the screen via the GameScene class batch node.

   If I don't find a solution soon, I will probably just create a single ball controller object instance, which will create the CCSprites, add them to the GameScene batch, then add them to a CCArray and cycle or pick and choose from the CCArray to address a particular ball and manipulate it. This way I get my Game Sprites added to the GameScene batch and Z-Layered properly. There will just be no ball objects or a ball object class.

   Thinking about this makes my head hurt..

   Posted 11 months ago #
6. 

   MisterX
   Member

   I did it! I have object instances for everything. I am as Objective as Objective-C can get with my first group of game objects, and they are all drawn in one batch with the background elements at their proper Z-Depth. It is a great feeling when things actually work for a change.

   I have a question though about object releasing in the dealloc method. If I have the following init method creating instances of the ball object, and they are all added via "addObject" to a CCArray, is it enough to simply add a release statement for the CCArray in my dealloc method (of the class that is creating the ball instances) to prevent a memory leak?

   #define kNumBalls 4
   
   @implementation BallController
   
   -(id) init {
   
   	if ((self = [super init])) {
   
   	CCLOG(@"init within BallController has been called");
   
   	ballsArray = [[CCArray alloc] initWithCapacity:kNumBalls];
   
   	for (int i = 0; i < kNumBalls; i++) {
   
   	BallObject* aBall = [[BallObject alloc] init];
   	[ballsArray addObject:aBall];
   
   	}
   
   	nextInactiveBall = 0;
   
   	}
   
   	return self;
   }
   
   -(void) dealloc {
   
   	[ballsArray release];
   	[super dealloc];
   }

   By just releasing the ballsArray, will the 4 BallObject instances contained within the ballsArray also get released along with the ballsArray itself?

   Posted 11 months ago #
7. 

   RelicaGames
   Member

   Unless I'm wrong, I believe that once the ballsArray is released, the objects inside it should release as well (if they're not retained by anything else). But I'm not entirely sure.... to be safe, you could just put [ballsArray removeAllObjects]; before it gets released.

   Posted 11 months ago #

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