ios - Deallocate SKScene after transition to another SKScene in SpriteKit

Question

I have a view controller that has three skscenes as children.

When I transition from one to another, the old skscene doesn't get deallocated.

I want it to get deallocated as if it was never there.

Example:

When I first load the app, only 1 skscene is visible (say it takes up 100mb memory), then I transition to another (100mb more), and then the third (300mb memory).

I would end up with 300mb memory and I want to have 100 at all times.

How can I achieve this?

My view controller: 

//
//  ViewController.m
//  Paddle Jumper
//
//  Created by Chance Daniel on 1/18/14.
//  Copyright (c) 2014 Max Hudson. All rights reserved.
//

#import "Flurry.h"
#import "ViewController.h"
#import "startViewController.h"

@implementation ViewController{
    BOOL sceneSetUp;
}

- (void)viewWillLayoutSubviews
{
    if(!sceneSetUp){

        [super viewWillLayoutSubviews];

        // Configure the view.
        SKView * skView = (SKView *)self.view;
        //skView.showsFPS = YES;
        //skView.showsNodeCount = YES;

        NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
        if([[defaults objectForKey:@"firstTime"] intValue] != 1){
            [defaults setObject:[NSNumber numberWithInt:1] forKey:@"firstTime"];

            [defaults setObject:@"ggr" forKey:@"skinSelected"];
            [defaults setObject:[NSNumber numberWithInt:2] forKey:@"ggrOwned"];

            [defaults setObject:[NSNumber numberWithInt:5000] forKey:@"gona"];
            [defaults setObject:[NSNumber numberWithInt:1500] forKey:@"points"];
            [defaults setObject:[NSNumber numberWithInt:7] forKey:@"livesLeftValue"];
            [defaults setObject:[NSNumber numberWithInt:3] forKey:@"shieldsLeftValue"];
            [defaults setObject:[NSNumber numberWithInt:2] forKey:@"lvlTwoLeftValue"];
            [defaults setObject:[NSNumber numberWithInt:0] forKey:@"lvlThreeLeftValue"];
        }

        if(![defaults objectForKey:@"tut_game1"]){
            [defaults setObject:[NSNumber numberWithInt:1] forKey:@"tut_game1"];
            [defaults setObject:[NSNumber numberWithInt:1] forKey:@"tut_store"];
            [defaults setObject:[NSNumber numberWithInt:1] forKey:@"tut_daily"];
        }

        [defaults synchronize];

        // Create and configure the scene.
        SKScene * startScene = [StartViewController sceneWithSize:skView.bounds.size];
        startScene.scaleMode = SKSceneScaleModeAspectFill;

        // Present the scene.
        [skView presentScene:startScene];
        //[skView presentScene:scene];

        sceneSetUp = YES;
    }

}

-(void) switchScene{

}

- (BOOL)shouldAutorotate
{
    return YES;
}

- (NSUInteger)supportedInterfaceOrientations
{
    if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPhone) {
        return UIInterfaceOrientationMaskAllButUpsideDown;
    } else {
        return UIInterfaceOrientationMaskAll;
    }
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Release any cached data, images, etc that aren't in use.
}

@end

An SKScene that won't release: //
//  SettingsSKScene.m
//  Paddle Jumper
//
//  Created by Max Hudson on 3/15/14.
//  Copyright (c) 2014 Max Hudson. All rights reserved.
//

#import "SettingsSKScene.h"
#import "gameViewController.h"
#import "StoreScene.h"

@interface SettingsSKScene (){
    SKSpriteNode *bg;
    SKSpriteNode *masterOverlay;
    SKSpriteNode *wbox;
    SKSpriteNode *gamecenter;
    SKSpriteNode *max;
    SKSpriteNode *chance;
    SKSpriteNode *bryce;
    SKSpriteNode *home;
    SKSpriteNode *play;

    SKSpriteNode *chance_link;
    SKSpriteNode *max_link;
    SKSpriteNode *bryce_link;

    SKSpriteNode *fbButton;
    SKSpriteNode *fbToggleYes;
    SKSpriteNode *fbToggleNo;

    SKLabelNode *story1;
    SKLabelNode *story2;
    SKLabelNode *story3;

    SKLabelNode *chance_name;
    SKLabelNode *max_name;
    SKLabelNode *bryce_name;

    SKLabelNode *chance_role;
    SKLabelNode *max_role;
    SKLabelNode *bryce_role;

    SKLabelNode *chance_handle;
    SKLabelNode *max_handle;
    SKLabelNode *bryce_handle;

    SKTexture *bg_texture;
    SKTexture *gamecenter_texture;
    SKTexture *wbox_texture;
    SKTexture *max_texture;
    SKTexture *chance_texture;
    SKTexture *bryce_texture;
    SKTexture *home_texture;
    SKTexture *play_texture;
    SKTexture *fb_texture;
    SKTexture *toggle_yes_texture;
    SKTexture *toggle_no_texture;
}

@end

@implementation SettingsSKScene

-(id) initWithSize:(CGSize)size{
    if(self = [super initWithSize:size]){
        masterOverlay = [SKSpriteNode spriteNodeWithColor:[SKColor blackColor] size:self.frame.size];
        masterOverlay.position = CGPointMake(self.frame.size.width/2, self.frame.size.height/2);
        [self addChild:masterOverlay];

        bg_texture = [SKTexture textureWithImageNamed:@"settings_bg"];
        wbox_texture = [SKTexture textureWithImageNamed:@"white_rect_bg"];
        gamecenter_texture = [SKTexture textureWithImageNamed:@"gc"];
        max_texture = [SKTexture textureWithImageNamed:@"max"];
        chance_texture = [SKTexture textureWithImageNamed:@"chance"];
        bryce_texture = [SKTexture textureWithImageNamed:@"bryce"];
        home_texture = [SKTexture textureWithImageNamed:@"home_light"];
        play_texture = [SKTexture textureWithImageNamed:@"play_light"];
        fb_texture = [SKTexture textureWithImageNamed:@"fb_light"];
        toggle_yes_texture = [SKTexture textureWithImageNamed:@"toggle_yes"];
        toggle_no_texture = [SKTexture textureWithImageNamed:@"toggle_no"];

        NSArray *to_preload = @[bg_texture, wbox_texture, gamecenter_texture, max_texture, chance_texture, bryce_texture, home_texture, play_texture, fb_texture, toggle_yes_texture, toggle_no_texture];

        [SKTexture preloadTextures:to_preload withCompletionHandler:^{
            [self fadeRemove:masterOverlay];
            [self initialize];
        }];
    }
    return self;
}

-(void) fadeRemove: (SKNode *) node{
    double duration = arc4random() % 10;
    duration *= 0.05;
    SKAction *fadeOut = [SKAction fadeOutWithDuration:0.1+duration];
    SKAction *remove = [SKAction runBlock:^{
        [node removeFromParent];
    }];

    [node runAction:[SKAction sequence:@[fadeOut, remove]]];
}

-(void) initialize{
    bg = [SKSpriteNode spriteNodeWithTexture:bg_texture];
    bg.position = CGPointMake(self.frame.size.width/2, self.frame.size.height/2);
    bg.zPosition = 0;

    wbox = [SKSpriteNode spriteNodeWithTexture:wbox_texture];
    wbox.position = CGPointMake(self.frame.size.width/2, 70);
    wbox.alpha = 0.8;
    wbox.zPosition = 2;

    gamecenter = [SKSpriteNode spriteNodeWithTexture:gamecenter_texture];
    gamecenter.position = CGPointMake(self.frame.size.width/2 + 100, self.frame.size.height/2-2);
    gamecenter.name = @"gc";
    gamecenter.zPosition = 2;

    fbButton = [SKSpriteNode spriteNodeWithTexture:fb_texture];
    fbButton.size = CGSizeMake(36, 36);
    fbButton.position = CGPointMake(self.frame.size.width/2 - 115, self.frame.size.height/2-2);
    fbButton.name = @"fb";
    fbButton.zPosition = 2;

    fbToggleNo = [SKSpriteNode spriteNodeWithTexture:toggle_no_texture];
    fbToggleNo.position = CGPointMake(self.frame.size.width/2 - 50, self.frame.size.height/2-2);
    fbToggleNo.size = CGSizeMake(fbToggleNo.size.width/3, fbToggleNo.size.height/3);
    fbToggleNo.name = @"fbno";
    fbToggleNo.zPosition = 2;

    fbToggleYes = [SKSpriteNode spriteNodeWithTexture:toggle_yes_texture];
    fbToggleYes.position = CGPointMake(self.frame.size.width/2 - 70, self.frame.size.height/2-2);
    fbToggleYes.name = @"fbyes";
    fbToggleYes.zPosition = 2;

    int hpBuffer = 40;
    int hpZ = 2;

    home = [SKSpriteNode spriteNodeWithTexture:home_texture];
    home.position = CGPointMake(hpBuffer, self.frame.size.height - hpBuffer);
    home.zPosition = hpZ;
    home.name = @"home";

    play = [SKSpriteNode spriteNodeWithTexture:play_texture];
    play.position = CGPointMake(self.frame.size.width - hpBuffer, self.frame.size.height - hpBuffer);
    play.zPosition = hpZ;
    play.name = @"play";

    [self addChild:bg];
    [self addChild:wbox];
    [self addChild:gamecenter];
    [self addChild:home];
    [self addChild:play];

    [self addChild:fbButton];
    [self addChild:fbToggleNo];

    [self addCredits];
    [self addStory];
}

-(void) addCredits{
    /* images */

    int cmbZ = wbox.zPosition + 1;
    int cmbY = wbox.position.y;
    int cmbXUnit = 132;
    int cmbX = self.frame.size.width/2 - (3*cmbXUnit)/2 + 20;
    int cmbWidth = 40;

    chance  = [SKSpriteNode spriteNodeWithTexture:chance_texture];
    max = [SKSpriteNode spriteNodeWithTexture:max_texture];
    bryce  = [SKSpriteNode spriteNodeWithTexture:bryce_texture];

    chance.zPosition = cmbZ;
    max.zPosition = cmbZ;
    bryce.zPosition = cmbZ;

    chance.position = CGPointMake(cmbX+cmbXUnit*0, cmbY+3);
    max.position = CGPointMake(cmbX+cmbXUnit*1 + 10, cmbY);
    bryce.position = CGPointMake(cmbX+cmbXUnit*2 + 10, cmbY+5);

    chance.size = CGSizeMake(cmbWidth, (chance.size.height/chance.size.width)*cmbWidth);
    max.size = CGSizeMake(cmbWidth, (max.size.height/max.size.width)*cmbWidth);
    bryce.size = CGSizeMake(cmbWidth, (bryce.size.height/bryce.size.width)*cmbWidth);

    [self addChild:chance];
    [self addChild:max];
    [self addChild:bryce];

    /* names */

    int cmb_nameXUnit = 30;
    int cmb_nameY = wbox.position.y - 10;
    int cmb_nameFontSize = 18;

    chance_name = [SKLabelNode labelNodeWithFontNamed:@"BebasNeue"];
    max_name = [SKLabelNode labelNodeWithFontNamed:@"BebasNeue"];
    bryce_name = [SKLabelNode labelNodeWithFontNamed:@"BebasNeue"];

    chance_name.text = @"Chance Daniel";
    max_name.text = @"Max Hudson";
    bryce_name.text = @"Bryce Daniel";

    chance_name.fontColor = [SKColor blackColor];
    max_name.fontColor = [SKColor blackColor];
    bryce_name.fontColor = [SKColor blackColor];

    chance_name.horizontalAlignmentMode = SKLabelHorizontalAlignmentModeLeft;
    max_name.horizontalAlignmentMode = SKLabelHorizontalAlignmentModeLeft;
    bryce_name.horizontalAlignmentMode = SKLabelHorizontalAlignmentModeLeft;

    chance_name.position = CGPointMake(chance.position.x + cmb_nameXUnit, cmb_nameY);
    max_name.position = CGPointMake(max.position.x + cmb_nameXUnit, cmb_nameY);
    bryce_name.position = CGPointMake(bryce.position.x + cmb_nameXUnit, cmb_nameY);

    chance_name.fontSize = cmb_nameFontSize;
    max_name.fontSize = cmb_nameFontSize;
    bryce_name.fontSize = cmb_nameFontSize;

    chance_name.zPosition = cmbZ;
    max_name.zPosition = cmbZ;
    bryce_name.zPosition = cmbZ;

    [self addChild:chance_name];
    [self addChild:max_name];
    [self addChild:bryce_name];

    /* roles */

    int cmb_roleY = wbox.position.y - 25;
    int cmb_roleFontSize = 11;

    chance_role = [SKLabelNode labelNodeWithFontNamed:@"BebasNeue"];
    max_role = [SKLabelNode labelNodeWithFontNamed:@"BebasNeue"];
    bryce_role = [SKLabelNode labelNodeWithFontNamed:@"BebasNeue"];

    chance_role.text = @"Programmer";
    max_role.text = @"Programmer";
    bryce_role.text = @"Graphic Designer";

    chance_role.fontColor = [SKColor darkGrayColor];
    max_role.fontColor = [SKColor darkGrayColor];
    bryce_role.fontColor = [SKColor darkGrayColor];

    chance_role.horizontalAlignmentMode = SKLabelHorizontalAlignmentModeLeft;
    max_role.horizontalAlignmentMode = SKLabelHorizontalAlignmentModeLeft;
    bryce_role.horizontalAlignmentMode = SKLabelHorizontalAl

Answer 1

A similar problem was faced by the person who asked this question.

When asked whether he was able to solve it, they said:

Yes, I did, there wasn't anything I could do about it from the scene or Sprite Kit for that matter, I simply needed to remove the scene and the view containing it completely from the parent view, cut all its bonds to the other parts of the system, in order for the memory to be deallocated as well.

You should use separate views for each of your scene and transition between these views. You can follow these steps to make it look natural:

1 - At the point you want to transition from one scene to the other, take a snapshot of the scene using the following code:

UIGraphicsBeginImageContextWithOptions(self.view.bounds.size, NO, scale);
[self drawViewHierarchyInRect:self.bounds afterScreenUpdates:YES];
UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

Then, add this image as a subview of the SKView of the current scene, and remove the scene.

2 - Initialise the new scene on another view, and transition between the two views using UIView animation.

3 - Remove the first view from it's superview.