CCDirector: PopToScene

[neuroscript]

I've been using my own version of such a method for quite some time. I figured, by now, someone else might have requested it.

For clarification:
1. Assume a scene stack as: Root -> S1 -> S2 -> S3.
2. Assume a button (B1) on S3 to go back to S1.

Pressing B1: [[CCDirector sharedDirector] popToScene:S1]

This would result in unwinding the stack to S1, such that it is: Root -> S1

[tiggybouncer]

I'm a bit lost... are you asking if there is a function where you can recall a previously created scene??

If so, when you leave S1, you would do something along the lines of [[CCDirector sharedDirector]pushScene:]; and then to retrieve it: [[CCDirector sharedDirector]popScene:]; .

Feel free to elaborate more if that wasn't what you meant

[neuroscript]

Sorry it was not clear:
WITHOUT using "replaceScene" for the various scenes, how can one POP to a scene further back than 1 scene, but not to the root?

A native iOS parallel would be:
- (NSArray *)popToViewController:(UIViewController *)viewController animated:(BOOL)animated; // Pops view controllers until the one specified is on top. Returns the popped controllers.

I wrote the code to do it long ago, but had to modify it for CC v3. It would be nice to have that in CC.

[skyhawk]

This is what I use (that allows transitions)
.h`

import "cocos2d.h"

@interface CCDirector (CCDirectorPopScene)
// honestly, why does this not exist?
- (void) popSceneWithTransition: (Class)c duration:(ccTime)t;
@end

.m

import "CCDirectorPopScene.h"

@implementation CCDirector (CCDirectorPopScene)
// honestly, why does this not exist?
-(void) popSceneWithTransition: (Class)transitionClass duration:(ccTime)t;
{
NSAssert( runningScene_ != nil, @"A running Scene is needed");

[scenesStack_ removeLastObject];  
NSUInteger c = [scenesStack_ count];  
if( c == 0 ) {  
	[self end];  
} else {  
	CCScene* scene = [transitionClass transitionWithDuration:t scene:[scenesStack_ objectAtIndex:c-1]];  
	[scenesStack_ replaceObjectAtIndex:c-1 withObject:scene];  
	nextScene_ = scene;  
}

}
@end
`

EDIT: I realize this is not exactly what you asked for, but the code should be enough to give you an idea on how to extend the CCDirector easy enough.

[neuroscript]

@skyhawk

That code will just pop off the scene that's on the top of the stack (with a transition)...not to a scene somewhere between root and top.

Here's the code I have been using (which needed an update for v3):

-(void)popToScene:(CCScene *)scene duration:(NSTimeInterval)t {  

NSAssert( _runningScene != nil, @"A running Scene is needed");  

CCScene* s = nil;  
Boolean found = NO;  
for( s in _scenesStack ) {  

	if( s == scene ) {  

		found = YES;  
		break;  
	}  
}  
if( !found ) NSAssert( NO, @"Scene is not in stack." );  

NSUInteger c = [_scenesStack count];  
if( c == 1 ) {  

	[self end];  
	return;  
}  

NSInteger idx = c - 2;  
do {  

	if( idx <= 0 ) {  

		[self end];  
		return;  
	}  

	s = [_scenesStack objectAtIndex:idx];  

	if( s == scene ) {  

		[self popSceneWithTransition:[CCTransition transitionFadeWithDuration:t]];  
		break;  
	}  
	else {  
		  
		s = [_scenesStack lastObject];  

		if( [s isRunningInActiveScene] ) [s onExit];  
		[s removeFromParentAndCleanup:YES];  
		  
		[_scenesStack removeLastObject];  
		idx--;  
	}  
}  
while( s != scene );

}

I see there's a private function for CCDirector:
-(void) popToSceneStackLevel:(NSUInteger)level;

But, you'd have to know the numeric level and subclass CCDirector to access it (or extend like I have been).

[neuroscript]

not sure why the board hosed up the code. But, in the last "else", the "if();;" should be:

		if( [s isRunningInActiveScene] ) [s onExit];  
		[s removeFromParentAndCleanup:YES];

[neuroscript]

omg. I'll try in different syntax

if s->isRunningInActiveScene then s->onExit;

s->removeFromParentAndCleanup( YES);

[birkemose]

You are correct, that the director only supports LIFO stack. If you need to juggle scenes differently, you could simply retain then in an NSMutableArray, and do the magic yourself.

[neuroscript]

@Birkemose
Tis what I've done for years. That's why I bring it up here in hopes that it could be added!