SpriteKit reference nodes from level editor - ios

Question

I'm using the scene editor in SpriteKit to place color sprites and assign them textures using the Attributes Inspector. My problem is trying to figure out how to reference those sprites from my GameScene file. For example, I'd like to know when a sprite is a certain distance from my main character.
Edit - code added
I'm adding the code because for some reason, appzYourLife's answer worked great in a simple test project, but not in my code. I was able to use Ron Myschuk's answer which I also included in the code below for reference. (Though, as I look at it now I think the array of tuples was overkill on my part.) As you can see, I have a Satellite class with some simple animations. There's a LevelManager class that replaces the nodes from the scene editor with the correct objects. And finally, everything gets added to the world node in GameScene.swift.
Satellite Class
func spawn(parentNode:SKNode, position: CGPoint, size: CGSize = CGSize(width: 50, height: 50)) {
parentNode.addChild(self)
createAnimations()
self.size = size
self.position = position
self.name = "satellite"
self.runAction(satAnimation)
self.physicsBody = SKPhysicsBody(circleOfRadius: size.width / 2)
self.physicsBody?.affectedByGravity = false
self.physicsBody?.categoryBitMask = PhysicsCategory.satellite.rawValue
self.physicsBody?.contactTestBitMask = PhysicsCategory.laser.rawValue
self.physicsBody?.collisionBitMask = 0
}
func createAnimations() {
let flyFrames:[SKTexture] = [textureAtlas.textureNamed("sat1.png"),
textureAtlas.textureNamed("sat2.png")]
let flyAction = SKAction.animateWithTextures(flyFrames, timePerFrame: 0.14)
satAnimation = SKAction.repeatActionForever(flyAction)
let warningFrames:[SKTexture] = [textureAtlas.textureNamed("sat8.png"),
textureAtlas.textureNamed("sat1.png")]
let warningAction = SKAction.animateWithTextures(warningFrames, timePerFrame: 0.14)
warningAnimation = SKAction.repeatActionForever(warningAction)
}
func warning() {
self.runAction(warningAnimation)
}
Level Manager Class
import SpriteKit
class LevelManager
{
let levelNames:[String] = ["Level1"]
var levels:[SKNode] = []
init()
{
for levelFileName in levelNames {
let level = SKNode()
if let levelScene = SKScene(fileNamed: levelFileName) {
for node in levelScene.children {
switch node.name! {
case "satellite":
let satellite = Satellite()
satellite.spawn(level, position: node.position)
default: print("Name error: \(node.name)")
}
}
}
levels.append(level)
}
}
func addLevelsToWorld(world: SKNode)
{
for index in 0...levels.count - 1 {
levels[index].position = CGPoint(x: -2000, y: index * 1000)
world.addChild(levels[index])
}
}
}
GameScene.swift - didMoveToView
world = SKNode()
world.name = "world"
addChild(world)
physicsWorld.contactDelegate = self
levelManager.addLevelsToWorld(self.world)
levelManager.levels[0].position = CGPoint(x:0, y: 0)
//This does not find the satellite nodes
let satellites = children.flatMap { $0 as? Satellite }
//This does work
self.enumerateChildNodesWithName("//*") {
node, stop in
if (node.name == "satellite") {
self.satTuple.0 = node.position
self.satTuple.1 = (node as? SKSpriteNode)!
self.currentSatellite.append(self.satTuple)
}
}

Answer 1

The Obstacle class
First of all you should create an Obstacle class like this.
class Obstacle: SKSpriteNode { }
Now into the scene editor associate the Obstacle class to your obstacles images
The Player class
Do the same for Player, create a class
class Player: SKSpriteNode { }
and associate it to your player sprite.
Checking for collisions
Now into GameScene.swift change the updated method like this
override func update(currentTime: CFTimeInterval) {
/* Called before each frame is rendered */
let obstacles = children.flatMap { $0 as? Obstacle }
let player = childNodeWithName("player") as! Player
let obstacleNearSprite = obstacles.contains { (obstacle) -> Bool in
let distance = hypotf(Float(player.position.x) - Float(obstacle.position.x), Float(player.position.y) - Float(obstacle.position.y))
return distance < 100
}
if obstacleNearSprite {
print("Oh boy!")
}
}
What does it do?
The first line retrieves all your obstacles into the scene.
the second line retrieves the player (and does crash if it's not present).
Next it put into the obstacleNearSprite constant the true value if there is at least one Obstacle at no more then 100 points from Player.
And finally use the obstacleNearSprite to print something.
Optimizations
The updated method gets called 60 times per second. We put these 2 lines into it
let obstacles = children.flatMap { $0 as? Obstacle }
let player = childNodeWithName("player") as! Player
in order to retrieves the sprites we need. With the modern hardware it is not a problem but you should save references to Obstacle and Player instead then searching for them in every frame.
Build a nice game ;)

Answer 2

you will have to loop through the children of the scene and assign them to local objects to use in your code
assuming your objects in your SKS file were named Obstacle1, Obstacle2, Obstacle3
Once in local objects you can check and do whatever you want with them
let obstacle1 = SKSpriteNode()
let obstacle2 = SKSpriteNode()
let obstacle3 = SKSpriteNode()
let obstacle3Location = CGPointZero
func setUpScene() {
self.enumerateChildNodesWithName("//*") {
node, stop in
if (node.name == "Obstacle1") {
self.obstacle1 = node
}
else if (node.name == "Obstacle2") {
self.obstacle2 = node
}
else if (node.name == "Obstacle3") {
self.obstacle3Location = node.position
}
}
}