How do I create a node using inheritance? - swift

Question

I would like to create a node of the subclass Unit from GameScene.swift. The code can be executed, but you can't see a node.
I use the following code:
GameScene.swift
func setFirstUnit() {
let myUnit = Unit(pHealthpoints: 10, pDamage: 5, pMovement: 1)
myUnit.position = CGPoint(x: self.size.width / 2, y: self.size.height / 2)
self.addChild(myUnit)
}
Unit.swift
class Unit: SKNode{
var healthPoints: Int
var damage: Int
var movement: Int
var texture: SKTexture
let knightTexture = "KnightBlueV2"
init(pHealthpoints: Int, pDamage: Int, pMovement: Int) {
healthPoints = pHealthpoints
damage = pDamage
movement = pMovement
texture = SKTexture(imageNamed: knightTexture)
let unit = SKSpriteNode(texture: texture)
unit.zPosition = 4
unit.setScale(1)
super.init()
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
I would be very grateful for any answer.

Answer 1

You are inheriting from SKNode, which has no properties to display anything on the screen. That's why nothing shows up on the screen. If you want to see something on the screen, you need to inherit from SKSpriteNode or another node class with visible properties you can see on the screen.
There's a better solution for you than inheriting from one of the SpriteKit node classes. Instead of using inheritance, use composition. Give the Unit class a property of type SKSpriteNode and use that property to load textures, move the unit, and display the unit on the screen.
class Unit {
sprite: SKSpriteNode
// Rest of class here.
}