Memory Management « cocos2d for iPhone

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Memory Management

(6 posts) (2 voices)

Started 2 years ago by Zammy
Latest reply from Codemattic

Tags:

memory management

Zammy
Member

Hello everyone, I am just starting developing for the iPhone/iPod and cocos2d.
I have couple of questions for memory management.

1. When i do [[Director sharedDirector] replaceScene:[Game scene]]; is release message called for the replaced scene?
2.When I create an action do I need to release it myself or it gets released when action is finished?
3.Does actions keep state or they just represent delta (change in time of a property) ?
4.What should I cleanup when a scene is changed? (in the dealloc method)
5.When release is called to a CocosNode does it call release to all children?

Sorry for many questions and thank you for your answers.

Evgeni

Posted 2 years ago #
Codemattic
Moderator

"1. When i do [[Director sharedDirector] replaceScene:[Game scene]]; is release message called for the replaced scene?"

Dont worry about it. Does your object need to keep a reference to a Scene? Then retain it. If not, let the other objects worry about their own memory management. If you dont retain something, dont expect it to stick around. If you pass an object to 2nd object, its up to that 2nd object to retain/release it if it wants to keep it.

"2.When I create an action do I need to release it myself or it gets released when action is finished?"

Again - concentrate on your own object's needs. Does your object need to keep a reference to an specific action? Then retain it. Otherwise dont worry about it.

"4.What should I cleanup when a scene is changed? (in the dealloc method)"

Any variables that you retained, dealloc them.

"3.Does actions keep state or they just represent delta (change in time of a property) ?"

I think all of the state that changes is in the CocosNode that the action is applied to. The Actions themselves hold the time and target states.

"5.When release is called to a CocosNode does it call release to all children?"

Again, dont worry about it. Trust the Cocos and Cocoa libraries to "do the right thing". If you need something retain it. But yes they do release them.

Posted 2 years ago #
Zammy
Member

I am not sure if I heard real answers :) but maybe I have memory problem somewhere else.

if I have something like

self->barsLayer = [Layer node]; [self addChild:self->barsLayer];
<p>then I should release the layer on dealloc? Because "node" msg is not init new or copy message. By Apple rules I should not worry about it.</p>
<p>edit:
Because it is in a Scene when the Scene is dealloced it will call release on the Layer.
So what I get is a weak reference in the member variable (or instance variables as they say in Apple world) ?`

Posted 2 years ago #
Codemattic
Moderator

I would retain barsLayer. And I would release barsLayer on dealloc. You may not get a memory error bc self->children will also retain it. But since barsLayer is an instance variable I would always retain/release it too.

Posted 2 years ago #
Zammy
Member

Thank you for your answers, I found my problem.
I created an array like [NSMutableArray array]; rather than [[NSMutableArray alloc] init]: .
I am not sure why, I guess it was not autoreleased with init/alloc.

Thank you again, I didn't want to be rude, I was making a joke with my first sentence.

Posted 2 years ago #
Codemattic
Moderator
"I guess it was not autoreleased with init/alloc." nope. init/alloc returns with a retain count of 1. The +array class method in [NSMutableArray array] which returns an array autoreleased is called a convenience constructor. Want to see how its done? Look at CocosNode.c and look at the +node convenience constructor:
```
+(id) node
{
	return [[[self alloc] init] autorelease];
}
```
So really what the convenience constructor does behind the scenes is it uses alloc/init and then just returns it autoreleased to save you some typing.
Posted 2 years ago #

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