Stop/Interrupt Transitions « cocos2d for iPhone

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Stop/Interrupt Transitions

(10 posts) (5 voices)

Started 2 years ago by Ravenmann
Latest reply from Benihana

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Ravenmann
Member
Hi

I'm using transitions a lot in my game, everything works fine. But when I try to interrupt/stop the transition with a touch it doesn't work. Is it possible to stop a transition with a touch event?

Here is my setup:

With the following I switch between Scenes as said before and it works great.
```
[[CCDirector sharedDirector] replaceScene: [TransitionScene transitionWithDuration:kTransitionTime scene: [StoryScene scene] withColor:ccBLACK]];
```
The TransitionScene class is a CCFadeTransition derived class.
It has a Layer (TransitionLayer) for receiving touch events to stop the Transition and switch to the main menu. TransitionScene overwrites initWithDuration in this way:
```
-(id) initWithDuration:(ccTime)d scene:(CCScene*)s withColor:(ccColor3B)aColor
{
	if( (self=[super initWithDuration:d scene:s withColor:aColor]) ) {
		// 'layer' is an autorelease object.
		TransitionLayer *layer = [TransitionLayer node];

		[layer setIsTouchEnabled:YES];
		[layer setNextScreen:@"MenuScene"];
		[layer setTargetedDelegate:NO];
		// add layer as a child to scene

		[self addChild: layer z:5];
	}

	return self;
}
```
Do I miss something or don't understand cocos2d architecture, when try to stop a transition and switch to another scene?

Thanks a lot
Martin
Posted 2 years ago #
gaminghorror
Member

I think it's a bad idea and in any case unnecessary to try to detect touches in the transition itself. Instead i would let the actual CCScene check for touches during the transition and change the scene as needed.

I do wonder why you would want a Fade transition but allow it to be aborted? If you think the user may be impatient enough to skip the fading, then don't fade, or fade faster.

Posted 2 years ago #
Ravenmann
Member

Hi gaminghorror

You are right that was my first try, to detect touches in the CCLayer corresponds to the CCScene but then I see that the automatic transition doesn't work anymore. Only the manual switch to the next transition works in this case.

My next try is shown above and does not work either. At the moment i ignore it and start the transition by default with no user interaction.

Martin

Posted 2 years ago #
v3nom
Member

Hello:

I'm using this topic to ask my question since the problem is quite the same. I need to know how can I tell to the CCDirector to stop the replaceScene method it is running.

Is there any way to stop the transitions that the CCDirector is running?

Many thanks!

Posted 1 year ago #
v3nom
Member

Hello?

Anyone? :D

Posted 1 year ago #
Dragyn
Member

Like @gaminghorror said originally in this thread, this sounds like a very bad idea. The new scene is already being instantiated during the transition, so if you can break into it, you might have a mess of partially created and partially dealloc'd objects on your hands.

If you want a skippable or abortable transition, you're probably better off making your own transition effect inside the scene you're moving out of, and that way you can make an escape/abort touch handler in that routine. Look at the cocos2D source for the transition you want to use, and you might be able to copy the way the transition effects are created without using the built-in code.

Posted 1 year ago #
Benihana
Member

Like @gaminghorror said originally in this thread, this sounds like a very bad idea. The new scene is already being instantiated during the transition, so if you can break into it, you might have a mess of partially created and partially dealloc'd objects on your hands.

I don't think it's nearly that awful. The incoming scene needs to already be initialized when the transition init is called, and none of the objects within the outgoing scene should be released until the outgoing scene is dealloc'd, which shouldn't happen until the transition is complete. As long as your incoming scene init and dealloc are set up properly, you should be able to modify CCTransition to handle canceling.

But I could be way wrong, I don't have all my senses right now. Perhaps in the morning I can look at it again?

Posted 1 year ago #
Benihana
Member
Add the following to CCTransitionScene, and add the method to the header:
```
-(void) cancelTransition
{
	CCScene *tempScene = outScene_;
	outScene_ = inScene_;
	inScene_ = tempScene;
	[inScene_ stopAllActions];

	[self finish];
}
```
I tested it with the included test and it worked fine. That uses a CCTransitionSlideInT, so if you use a different kind of transition, your mileage might vary. Note that you need to make sure your scene's init and dealloc are properly set up. Also note that I'm probably not sober enough to be writing code, but I'm going to go work on some now, so who knows.

Also, if you want to test it out, add a variable CCScene *transitionScene to the layer1 and make the following changes in the implementation:
```
-(void) onPushSceneTran: (id) sender
{
	CCScene * scene = [CCScene node];
	[scene addChild: [Layer2 node] z:0];
	transitionScene = [CCTransitionSlideInT transitionWithDuration:5 scene:scene];
	[[CCDirector sharedDirector] pushScene:transitionScene ];
	[self schedule:@selector(cancelT) interval:3];
}

-(void) cancelT
{
	[transitionScene cancelTransition];
	[self unschedule:@selector(cancelT)];
}
```
Posted 1 year ago #
v3nom
Member

Hi:

First of all thanks for taking your time to answer me. I tried the code of Benihana but I couldn't get it to work, the game was still crashing at the same point I tried to cancel de transition but I suppose it is my fault and not yours.

I solved the problem changing my logic a little bit so that I didn't need to stop the transition.

It would be great if the feature could be implemented in the Cocos2d classes, I'm sure it would be useful in many cases although I don't know the consequences of doing it so I must be dreaming awake.

Thanks again!!

Posted 1 year ago #
Benihana
Member

But when I try to interrupt/stop the transition with a touch it doesn't work.

My next try is shown above and does not work either.

but I couldn't get it to work, the game was still crashing at the same point

It would be useful if you were more specific about the issues you're having. My wild guess is you are either leaking big time, accessing something that has been released, or performing initialization or deallocation of variables in the init/dealloc without a corresponding init/dealloc in your scene's init/dealloc. But it's pretty much impossible to tell without more information.

It would be great if the feature could be implemented in the Cocos2d classes, I'm sure it would be useful in many cases although I don't know the consequences of doing it so I must be dreaming awake.

I'll file a feature request. It would be trivial to include a skipTransition and cancelTransition, for skipping ahead to the next scene or canceling the replace scene and returning to the original one. The catch is that the user must take care when setting up their scene initialization and deallocating, so that they are perfectly symmetric.

I'm not terribly happy about the fact that I named a method "cancelT," or unscheduled the selector AFTER cancelTransition gets called (I believe the scene will have to wait until the selector is unscheduled to deallocate, essentially the scheduler is the last string keeping the transition and incoming scene in memory).

Oh, and the user should also note that if the outgoing scene has any user scheduled actions, they will be cancelled (because the transition does not keep a reference to the slide action or whatever, so it can't be cancelled explicitly). It would take a lot of refactoring to fix that, I think.

Posted 1 year ago #

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