cocos2d for iPhone

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

1. 

   Kevin
   Member

   I am new to Cocos2d and am having problems with one concept. In my game I have pieces scrolling across the screen that the player can grab. This part is easy. I randomly spawn a piece and scroll it with an action. The problem is figuring out what piece the user grabbed. My gut said subclass AtlasSprite but the AtlasSpriteManager wouldn't take the subclass as a child. Am I doing something wrong and/or what is the recommend way to track data about an AtlasSprite?

   Posted 2 years ago #
2. 

   Steve Oldmeadow
   Administrator

   All CocosNodes have a void pointer called userData that you can point to whatever you want. Alternatively there is an integer property called tag that you can set to whatever value you want, this could be an index into an array.

   Posted 2 years ago #
3. 

   Kevin
   Member

   userData sounds promising but I can't figure out how to use it. It always returns void.

   int i = 99;
   sp.userData = i;
   int x = sp.userData;

   When I run this code x is set to 0.

   Posted 2 years ago #
4. 

   hactar
   Member

   I subclass AtlasSprite all over the place and have no issues adding it to an AtlasSpriteManager (using 0.8.1 here). Are you sure you are subclassing AtlasSprite and not Sprite?

   Posted 2 years ago #
5. 

   Steve Oldmeadow
   Administrator

   @Kevin - userData is a void pointer if you want to store an int then use the tag. If you don't understand what a void pointer is just Google it there are lots of good tutorials.

   Posted 2 years ago #
6. 

   Kevin
   Member

   Thanks Steve. That makes sense. In other words my over simplified test was just that... too over simplified. The userData needs to be set to a pointer not a c-type.

   This works.

   NSString *str = [NSString stringWithFormat:@"Piece: %i", currentPiece];
   sp.userData = str;
   
   NSString *str2 = (NSString *) sp.userData;
   
   NSLog(@"String2 = %@", str2);

   I will just make an object to hold all of the data I need to track and it should work the same way. This is what I was planning to do in the first place.

   Posted 2 years ago #
7. 

   Kevin
   Member

   @hactar looks like I had done something wrong in my first test. This seems to be working fine now. The userData is very useful but in this case the subclassing works better.

   Thanks everyone for the help. I have been very impressed by cocos2d and look forward to learning more about it.

   Posted 2 years ago #
8. 

   serveace6
   Member

   Is subclassing AtlasSprite the way to go for characters/objects in a game? If so, would you handle all the collision and animation behaviors as well?

   Posted 2 years ago #

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