I have a custom class named Test that extends SKShapeNode with 4 SKShapeNodes as its child, and I would like to add them as a child of GameScene. However, when I try to execute addChild() in GameScene, I end up getting the error signal SIGABRT.
In my custom class I declare:
let shapeR = SKShapeNode()
let shapeG = SKShapeNode()
let shapeY = SKShapeNode()
let shapeB = SKShapeNode()
Then in override init(), I call the addChild() methods:
addChild(shapeR)
addChild(shapeG)
addChild(shapeY)
addChild(shapeB)
Finally in GameScene, I iterate through the children with (test is defined as Test()):
for child in test.children {
addChild(child)
}
How do I fix this?
Edit: I need 4 SKShapeNodes since I want 4 different colors in my custom SKShapeNode object.
Nevermind I just had to addChild() the entire class and not just separate SKShapeNodes
Related
this is more of a general question about subclasses and inheritance within Swift 4.
In Apple's developer guide, a subclass ("anySubclass") of a custom class ("anySuperclass") can directly access/inherit the parent's properties, e.g.:
anySubclass.anyProperty = xyz (anyProperty was only defined within the Superclass)
To my question:
I'm currently working on my first game using SpriteKit and wanted to create subclasses of SKSpriteNode, one of which should be clBackGround.
If I just define it as a subclass of SKSpriteNode, i.e.
class clBackGround:SKSpriteNode {
}
I would think that I could simply use all properties associated with SKSpriteNode just like this:
var bg1 = clBackGround()
bg1.size = ...
.
.
.
This does not seem to be working however. So my questions is:
Do I need to initialize all the properties of SKSpriteNode I want to use within clBackGround (using a designated initializer)? How can I then assign an image to an instance of this subclass?
Any help would be much appreciated!
Not sure if this is what you're asking, but, generally, if you create a subclass of an object, you don't need to do anything special to access the superclass's properties. They'll be initialized in the usual fashion.
However, you DO have to ensure that the superclass's initializers get called in a proper manner if you have your own initializers for your subclass.
In the case of a subclass of SKSpriteNode, if you define your own initializer for the subclass, that initializer will need to call the designated superclass initializer, which passes in the texture, color, and size to use for the sprite:
init(enemyType:String) {
let texture = SKTexture(imageNamed: "enemy_\(enemyType)")
let color = UIColor.black
let size = texture.size()
super.init(texture: texture, color: color, size: size)
}
What is the best way to add a sprite node after a scene has been fully loaded? The sequence looks like this:
1) I build the scene, GameScene().
2) Some time later, I download backend data and I use this info to build a SKSpriteNode in a different class, NodeBuilder().
3) I want to add this node to the instance of my scene that I'd already loaded.
What's the best way to achieve step 3)?
In GameScene:
addChild(yourNode)
For getting and keeping a reference to NodeBuilder:
Creation of NodeBuilder in GameScene:
class GameScene : SKScene {
var nodeBuilder = NodeBuilder() // Create an instance of NodeBuilder
func didMoveToView(skView: SKView) {
nodeBuilder.gameScene = self // Add self as the instance of GameScene that nodeBuilder has reference to
}
}
In NodeBuilder:
class NodeBuilder {
var gameScene : GameScene! // This is how you keep your reference
func addNodeToGameScene(node: SKNode) {
self.gameScene.addChild(node)
}
addNodeToGameScene(aNode) // This is how you would call the method to add a node to GameScene from NodeBuilder
}
If I create an instance of the class below and call the spawn function from my controller, the sprite will appear but I won't be able to change any of its properties.
class Hero: SKSpriteNode
{
var hero = SKSpriteNode(imageNamed: "hero3")
func spawn(parentNode: SKNode, position: CGPoint, size: CGSize = CGSize(width: 50, height: 50))
{
hero.size = size
hero.position = position
hero.physicsBody = SKPhysicsBody(circleOfRadius: 25)
hero.physicsBody?.allowsRotation = false
hero.zPosition = 10
parentNode.addChild(hero)
}
}
If I get rid of the hero property and change everything to self, it works fine.
class Hero: SKSpriteNode
{
func spawn(parentNode: SKNode, position: CGPoint, size:CGSize = CGSize(width: 50, height: 50))
{
self.size = size
self.position = position
self.texture = SKTexture(imageNamed: "hero3")
self.physicsBody = SKPhysicsBody(circleOfRadius: 25)
self.physicsBody?.allowsRotation = false
self.zPosition = 10
parentNode.addChild(self)
}
}
I'm sure this is swift 101, but can someone please explain why the first version doesn't work as expected?
In your first example, you created a var (basically a SpriteNode inside the SpriteNode).
When you instantiate the class like let hero = Hero(....) you now have a SpriteNode called hero, with a property called hero. You can change either. Calling hero.size would change the base hero, and hero.hero.size would change the inside SpriteNode....this is probably not the behavior you were looking for.
The second class looks correct, if you are just trying to create a SpriteNode and modify it. The class is a subclass of SpritNode, so it's already a SpriteNode - no need to create one inside it like the first one.
Hope this helps!
Your Hero class inherits from SKSpriteNode, so it is essentially an SKSpriteNode already, which means you don't need to create a hero SKSpriteNode variable.
In your first class, when you use hero.size = size, you're accessing the properties of the variable within your class instead of on the class itself. Then you add the hero SKSpriteNode as a child along with all its properties, but your class SKSpriteNode, which holds the variable doesn't have set properties size or a physics body. You can think of the class as a container that's holding the variable SKSpriteNode.
In your second function, when you use self.size = size, you're accessing the class's properties and giving the class SKSpriteNode all the properties you need to use it in other classes.
I create sprite node in my GameScene as the following. I would like to reuse createNodeA1 or nodeA1 in other SKScene. How can I do that?
import SpriteKit
class GameScene: SKScene {
var nodeA1: SKNode!
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
}
override init(size: CGSize) {
super.init(size: size)
// Add sprite node to the scene
nodeA1 = createNodeA1()
addChild(nodeA1)
}
}
// Create dot 1
func createNodeA1() -> SKNode {
let spriteNode = SKNode()
spriteNode.position = CGPointMake(CGRectGetMidX(self.frame)/1.5, CGRectGetMidY(self.frame)/2.0)
let sprite = SKSpriteNode(imageNamed: "dot_1")
sprite.zPosition = 3.0
sprite.name = "A1_Broj"
spriteNode.addChild(sprite)
return spriteNode
}
}
There is a few ways to do this.
You could subclass your other scenes to be subclass of the scene with the loadNode function which gives those scenes access to that function.
I asked a question about this last year
Swift multiple level scenes
Another way that might be a bit easier if you are not comfortable with scene subclassing is to just create a subclass of the node itself.
So you create a class
enum EnemyType {
case Normal
case Special
}
class NodeA1: SKSpriteNode {
init(imageNamed: String, enemyType: EnemyType) {
let texture = SKTexture(imageNamed: imageNamed)
if enemyType == .Normal {
super.init(texture: texture, color: SKColor.clearColor(), size: texture.size())
else {
// other init
}
self.zPosition = 1
self.name = ""
// add physics body, other properties or methods for the node
}
}
Than in your SKScenes you can add the node in the init method like so
nodeA1 = NodeA1(imageNamed: "ImageName", enemyType: .Normal)
nodeA1.position = ....
addChild(nodeA1)
this way ever scene where you add the node will use the subclass and therefore include all the properties, set up etc for that node. Another benefit with subclassing is that you could loop through all your nodes using
self.enumerateChildNodesWithName...
and than call custom methods on all nodes.
If you want to subclass your scenes than you would create your baseScene
class BaseScene: SKScene {
// set up all shared stuff in didMoveToView
// have your node function here
// touches began
// physics word and contact collision
// all other stuff that needs to be shared between all level scenes
}
Than your subsequent level scenes would look something like this
class Level1Scene: BaseScene {
override func didMoveToView(view: SKView) {
super.didMoveToView(view) // This lines imports all stuff in BaseScene didMoveToView
// do level 1 specific setUps.
// you can call any function or property from BaseScene, e.g the loadNode function.
}
You than load you level scenes as usual, e.g you transition to level 1 scene and it will automatically use/have access to all the superclass methods and sprites (BaseScene).
So you never call baseScene directly, its gets called automatically.
This applies for other methods in baseScene too, so say you have a Update method in BaseScene.
override func update(currentTime: CFTimeInterval) {.... }
This will work across all your level scenes which are subclasses of BaseScene.
But what happens if you need to add some specific stuff to the update method only relevant in 1 level scene and not all level scenes?
It would be the same process, you create a new update func in the LevelScene and call super.
override func update(currentTime: CFTimeInterval) {
super.update(currentTime) // this calls the baseScene Update method
/// specific stuff for that level only
}
Super simply means the super class of the currentScene, which is BaseScene if the scene is a subclass of it.
Is this helping?
This is additional answer information in terms of subclass of the baseScene. We can create node1thru node10 all in baseScene. Then in Leve1Scene which is subclass of the baseScene, all we have to do is in didMoveToView function state node1.position = CGPointMake(....) for each node that we need in Level1Scene where we would specify node's position.
If we do not need to load all of the 10 nodes in Level1Scene, for example, let's say we don't need to load to the scene node10 we can simply in didMoveToView function just state node10.removeFromParent() and this node will not be loaded to Level1Scene but rest of 9 nodes will.
Note that this example uses only 10 nodes, but you can go with any number of nodes in your baseScene.
This way of subclassing will save you a lot repeatable code in subclasses.
I basically want to add a SKSpriteNode to the screen and I have no idea where the mistake it. So I include pictures of my three classes participating in this problem. I created a class for all the background stuff. There I use the function addChild() to add my 56 Nodes to the View but they do not appear on the screen. Theoretically (for me) everything should work.
Hopefully you can help me adding the Nodes to the screen!
Edit: Updated the pictures.
When you call this:
GameScene().addChild(image)
you every time inside for create the local GameScene object, add image to this object and when you move to the next iteration of the loop, this object is destroyed. In fact, after your loop thire is no one GameScene object.
Second, you don't need to use var image = SKSpriteNode() in your hintergrund object. You every time set this reference to new object.
You have the cross references in code, try to make somthing like this:
class GameScene: SKScene {
...
override func didMoveToView(view: UIView) {
hintergrund.setBackgroundForScene(self, width: screenWidht)
}
}
class hintergrund {
...
class func setBackgroundForScene(gameScene: GameScene, width: CGFloat) {
...
for (...) {
...
gameScene.addChild(image)
}
}
}