SpriteKit correct asset size

Question

Summary

I'm creating an SpriteKit game for different devices and I'm wondering what should be the size of the different assets.

What I have right now

I'm creating the SKScene in viewDidLoad:

scene = GameScene(size: view.bounds.size)
scene.scaleMode = .AspectFill

I don't want to use viewWillLayoutSubviews because it is called twice on start up and also each time the device is rotated. I don't think that initialising the scene here is a good idea.

With this configuration, my view is initialised with a width of 600 points (default storyboard size) and then rescaled to the device width. Using println(scene.size.width) after the view has been layout it displays a 375 points size in the iPhone 6 and 414 points in the iPhone 6 Plus.

I'm using xcassets to provide the background images and I would like to know which sizes should I use. My current configuration is ready for 320 points resolutions (iPhone 4, iPhone 5)

1x: 320 pixels
2x: 640 pixels
3x: 960 pixels

The problem

The problem is that the image will be rescaled in following devices:

iPhone 6: 750 pixels - 375 points
iPhone 6 Plus: 1242 pixels - 414 points
iPad: 768 pixels - 768 points
iPad retina: 1536 pixels - 768 points

I would like to know how am I supposed to configure the images and the SKScene size to optimise it for all the devices.

viewwilllayout is the recommended way, just check self.view == nil before presenting the scene — LearnCocos2D
I've already tried it and it initialises it at 600 pixels width in the first call and then to the correct 750 (iPhone 6) width. If I check that the scene is nil, it will be initialised at 600 pixels width, the same as in viewDidLoad. — Octan
I can do it correctly in the first call of viewDidLayoutSubviews (Notice the Did instead of Will) Do you think this is a good idea? — Octan

Whirlwind Whirlwind · Accepted Answer · 2015-01-14T10:14:04

If you don't want to initialize scene twice you can initialize it only once:

- (void)viewWillLayoutSubviews
{

    [super viewWillLayoutSubviews];


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

    if(!skView.scene){
    // Create and configure the scene.
        GameScene * scene = [GameScene sceneWithSize:skView.bounds.size];

        scene.scaleMode = SKSceneScaleModeAspectFill;

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

SpriteKit correct asset size

Summary

What I have right now

The problem

2 Answers