As I'm new to Swift iOS programming and I have question about creating "prefabs"?
I have Unity background and there was something like prefabs that you can instantiate many times. Is there anything similar to that in Swift or Xcode? Especially I'm looking for that in SpriteKit to create copy of SKNode with children
I think the closest thing to prefabs would be classes.
you can create a subclass of a SKnode or any other node, for example a SKSpriteNode and then setup that class to do the things you want. Then create an instance of that class.
class Box : SKSpriteNode{
init(){
//Setup your node the way you want it
super.init(texture: nil, color: UIColor.red, size: CGSize(width: 50, height: 50))
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
//create instance and add to scene.
let box = Box()
self.addChild(box)
you can also setup a node and then use the copy function to copy this node along with its children.
let block1 = SKSpriteNode(color: UIColor.red, size: CGSize(width: 50, height: 50))
let child = SKSpriteNode(color: UIColor.blue, size: CGSize(width: 25, height: 25))
block1.addChild(child)
let copy = block1.copy() as! SKSpriteNode
addChild(copy)
Related
I've coded a simple game using Swift 4 and XCode, and I've coded everything in the GameScene. All my elements (the monsters, the player, the projectile, etc.) are coded in the GameScene.
I want to transfer my code into dedicated classes (Class Player, class monster, etc.)
I would like to know what the basic structure of a SKSpriteNode class and the call of that class in the GameScene, to be more efficient at adapting my code.
Here's an example of what I've tried :
class Vaisseau: SKSpriteNode /*: Creatures */{
var coeur: Int = 0
init(texture: SKTexture, size: CGSize)
{
let texture = SKTexture(imageNamed: "player")
super.init(texture: texture, color: UIColor.clear, size: texture.size())
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
}
And the initialization in the GameScene :
let player = Vaisseau()
Here's how it is actually defined in the GameScene :
let player = SKSpriteNode(imageNamed: "player")
you are declaring your init to have two parameters (texture: SKTexture, size: CGSize) but you are not passing the parameters in your initialization call
let player = Vaisseau()
you either need to change the initialization to...
let texture = SKTexture(imageNamed: "player")
let player = Vaisseau(texture: texture, size: texture.size())
and change the init to
init(texture: SKTexture, size: CGSize) {
super.init(texture: texture, color: UIColor.clear, size: size)
}
OR change the init in the class to...
init() {
let texture = SKTexture(imageNamed: "player")
super.init(texture: texture, color: UIColor.clear, size: texture.size())
}
and leave your initialization call as...
let player = Vaisseau()
player.position = CGPoint(x: 500, y: 500)
addChild(player)
EDIT added the above 2 lines to show you that those need to be in the scene
but other items such as alpha, zPosition, actions, zRotation etc. can be inside of the class
What you need to ask yourself to figure out which one to use is "will the texture for the player ever be different?" if so you may want to consider the first option where you pass in the texture.
Can anyone help me solve this issue? The error shown is being generated even though I am using the designated initializer.
class OtherOrb: SKSpriteNode {
override init() {
let texture = SKTexture(imageNamed: "Orb")
super.init(texture: texture, color: UIColor.clear, size: texture.size()){
self.position = CGPoint(x: 0.0, y: 500.0)
self.physicsBody = SKPhysicsBody(circleOfRadius: 20)
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
You are getting this error because of the closure you have trailing your initialiser.
In Swift, the compiler interprets a closure directly after a method call as the final argument to said method call, and hence the error you are getting effectively says that no initialiser that includes that closure argument exists.
Furthermore, your code looks very off, and I'm not convinced it's valid Swift. What are you trying to accomplish?
Based on my suspicions, I believe your code should resemble the following:
class OtherOrb: SKSpriteNode {
init() {
let texture = SKTexture(imageNamed: "Orb")
super.init(texture: texture, color: UIColor.clear, size: texture.size())
self.position = CGPoint(x: 0.0, y: 500.0)
self.physicsBody = SKPhysicsBody(circleOfRadius: 20)
}
#available(*, unavailable)
override init(texture: SKTexture?, color: UIColor, size: CGSize) {
super.init(texture: texture, color: color, size: size)
}
#available(*, unavailable)
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
That is to say that you want an initialiser with no args to be your designated initialiser.
Attempting to design a game using Sprite-Kit I found that it would be easier to create a seperate class for one of my game objects being a laser from a ship. Within that class I would have some functions maybe such as updating, shooting etc. But whenever I create another class none of the variables I make are "declared". This is my code
import UIKit
import SpriteKit
class laser: SKSpriteNode {
let laser : SKSpriteNode = SKSpriteNode(imageNamed:"playerShip")
laser.position = CGPoint(x: 100, y: 200)//This is where it says no declaration
}
This is because you need to initiate the class.
In your example you would need to do the following which would allow you instantiate a laser like this laser()
class laser: SKSpriteNode {
let laser: SKSpriteNode = SKSpriteNode(imageNamed: "playerShip")
init() {
super.init(texture: nil, color: .clear, size: laser.size)
laser.position = CGPoint(x: 100, y: 200)
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
But you probably really wanted this, which allows you to instantiate a laser like this let aLaser = laser("playerShip"). Then you can change the position like this alaser.position = CGPoint(x: 100, y: 200).
This method allows you to change the sprite and position easily for different lasers. Unless your game only has one laser.
class laser: SKSpriteNode {
init(_ imageName: String) {
let texture: SKTexture = SKTexture(imageNamed: imageName)
super.init(texture: texture, color: .clear, size: texture.size())
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
I'm trying to make a class from this node so I can make various objects from it, but Xcode keeps saying "Expected Declaration". How can I make a class from my node? Here is the code that's giving me an error:
P.S. I am relatively new to StackOverflow, so if my question needs more details please let me know instead of putting it on hold. Thanks!
import SpriteKit
import GameplayKit
class GameScene: SKScene, SKPhysicsContactDelegate {
override func didMove(to view: SKView) {
class nodeClass{
let platform = SKSpriteNode(color: UIColor.yellow, size: CGSize(width: 400, height: 60))
platform.xScale = 0.8
platform.yScale = 0.8
platform.physicsBody = SKPhysicsBody(rectangleOf: CGSize(width: platform.size.width, height: platform.size.width / 6))
platform.position = CGPoint(x: 150, y: -100)
platform.physicsBody?.categoryBitMask = 1
platform.physicsBody?.collisionBitMask = 0
platform.physicsBody?.isDynamic = false
platform.physicsBody?.affectedByGravity = false
self.addChild(platform)
}
}
}
You should (ideally) declare and define your class outside of a function.
For lack of a better term, at the 'root' level of your file containing code.
For personal clarity, most folks, most of the time, create a new file and use that to hold their declaration and definition of all their classes can do. This isn't strictly necessary in Swift, but it's a helpful clarity technique for when you're starting out. As I am.
Next problem: nodeClass isn't, the way you've written it, subclassing anything. It's a 'standalone' type. By virtue of it not having anything after a colon stating what it's subclassing, it's an entirely new type.
Right above, you can see GameScene is a subclass of SKScene, because it's doing this. Any type names after the one being subclassed are Protocols GameScene is agreeing to conform to.
Ad #Confused just said, you should avoid declaring a class inside a method.
Here's a possible solution
class GameScene: SKScene, SKPhysicsContactDelegate {
override func didMove(to view: SKView) {
let platform = Platform(size: CGSize(width: 400, height: 60))
platform.xScale = 0.8
platform.yScale = 0.8
platform.position = CGPoint(x: 150, y: -100)
self.addChild(platform)
}
}
class Platform: SKSpriteNode {
init(size: CGSize) {
super.init(texture: nil, color: .yellow, size: size)
let physicsBody = SKPhysicsBody(rectangleOf: CGSize(width: size.width, height: size.width / 6)) // Are you sure about this??
physicsBody.categoryBitMask = 1
physicsBody.collisionBitMask = 0
physicsBody.isDynamic = false
physicsBody.affectedByGravity = false
self.physicsBody = physicsBody
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
I'm struggling to understand how class initialisation works. From looking at solutions to other problems I have this as an example of the classes in my app.
import Foundation
import SpriteKit
class Ground : SKSpriteNode {
override init(texture: SKTexture!, color: SKColor, size: CGSize) {
super.init(texture: texture, color: color, size: size)
self.zPosition = -20
self.name = "Ground";
}
func configure (size: CGSize, position: CGPoint) {
self.size = size
self.position = position
// Set up the Physics
self.physicsBody = SKPhysicsBody(rectangleOf: size)
self.physicsBody?.contactTestBitMask = PhysicsCategory.Player
self.physicsBody?.categoryBitMask = PhysicsCategory.Ground
self.physicsBody?.collisionBitMask = PhysicsCategory.All
self.physicsBody?.affectedByGravity = false
self.physicsBody?.allowsRotation = false
self.physicsBody?.isDynamic = false
self.physicsBody?.mass = 1.99999
}
convenience init(color: SKColor, isActive: Bool = false) {
let size = CGSize(width: 10, height: 10);
self.init(texture:nil, color: color, size: size)
}
required init?(coder aDecoder: NSCoder) {
// Decoding length here would be nice...
super.init(coder: aDecoder)
}
}
I've put the 'configure' function as a kludge fix to let me pass the scene to the class so I can set sizes depending on the size of the device screen. Ideally I would like to just pull this information on initialisation but everything I try throws up errors that I don't understand.
Im not sure which way would be correct but I was wondering firstly, how would I pass arguments to the class to start with.. e.g..
let myClass = Ground(scene: self)
or can I somehow pull the scene information from directly within the class? I can pass info into functions/methods as I did with 'configure' but I couldn't get it to work on initialisation which would certainly be cleaner.
How would you guys do it?
Size
You should not programmatically change the size of a sprite depending on the current device, just use the same size and then let SpriteKit resizing it for you.
Loading from .sks
This initializer
init?(coder aDecoder: NSCoder)
is used when the Sprite is loaded from a .sks file. However in Xcode 7 you cannot pass values from the .sks to the sprite to set the attributes. I'm not sure you are using a .sks file so for now I am just throwing a fatal_error here. In Xcode 8 however you will be able to pass values from the .sks file to your own class.
required init?(coder aDecoder: NSCoder) {
fatalError("Not implemented")
}
Scene
You don't need to pass a reference of the current scene to your class. Every SKNode has the scene property, just use it to retrieve the scene where the node lives. Of course keep in mind that if you invoke .scene before the node has been added to a scene it will returns nil.
Code
This is the final code
class Ground : SKSpriteNode {
init(color: SKColor = .clearColor(), isActive:Bool = false) {
let texture = SKTexture(imageNamed: "ground")
super.init(texture: texture, color: color, size: texture.size())
self.name = "Ground"
self.zPosition = -20
let physicsBody = SKPhysicsBody(texture: texture, size: texture.size())
physicsBody.contactTestBitMask = PhysicsCategory.Player
physicsBody.categoryBitMask = PhysicsCategory.Ground
physicsBody.collisionBitMask = PhysicsCategory.All
physicsBody.affectedByGravity = false
physicsBody.allowsRotation = false
physicsBody.dynamic = false
physicsBody.mass = 1.99999
self.physicsBody = physicsBody
}
required init?(coder aDecoder: NSCoder) {
fatalError("Not implemented")
}
}
Unless I'm missing something else you're trying to do, you should be able to move the initialization of the PhysicsBody and the other properties from you configure() method and into your init() for the class. Then you can pre-size the texture you pass in on instantiation to result in the proper size for the device.
Also, the position property of the SKSpriteNode can be set by the instantiating class. This means you can accomplish the sizing based on device and the setting of the position property right after instantiating it in your scene and before adding it as a child of the scene.
ADDED:
class Ground : SKSpriteNode {
override init(texture: SKTexture!, color: SKColor, size: CGSize) {
super.init(texture: texture, color: color, size: size)
}
convenience init(texture: String, scene: SKScene, isActive: Bool = false) {
let texture = SKTexture(imageNamed: "\(yourtexturename)")
self.init(texture:teture, color: color, size: scene.size)
self.size = size
self.position = [YOU CAN NOW SET POSITION BASED ON THE SCENE]
self.physicsBody = SKPhysicsBody(rectangleOf: size)
self.physicsBody?.contactTestBitMask = PhysicsCategory.Player
self.physicsBody?.categoryBitMask = PhysicsCategory.Ground
self.physicsBody?.collisionBitMask = PhysicsCategory.All
self.physicsBody?.affectedByGravity = false
self.physicsBody?.allowsRotation = false
self.physicsBody?.isDynamic = false
self.physicsBody?.mass = 1.99999
self.zPosition = -20
self.name = "Ground";
}
required init?(coder aDecoder: NSCoder) {
// Decoding length here would be nice...
super.init(coder: aDecoder)
}
}
You might not need to override the original init() method but I didn't test anything.