Sprite Kit efficient random node spawn - ios

Question

I am searching for the most efficient way to Nodes with random SKSpriteNodes on given positions.
I have 10 Platforms, on each of them I want to have an Enemy (SKNode) that contains for 3 different SKSpriteNodes which will randomly spawn. These SKSpriteNodes all do other behaviors, thats why I can't simply change the Texture of the SKNode.
As with my Code, I wanted to spawn the same Node on different Platforms.
However, the code does not work properly, the nodes do spawn but only at 1 position(the position from the last SpawnEnemycode in didMoveToView), meaning 10 nodes at 1 position.
I also tried it with adding 10 different Enemy nodes, each given a Platform. But this just looks like a copy & paste code thats inefficient.
How can I fix my problem, or is there either another way to spawn them more efficiently?
My Code:
class GameScene: SKScene, SKPhysicsContactDelegate {
var Enemy: SKNode!
override func didMoveToView(view: SKView) {
/* Setup your scene here */
self.physicsWorld.contactDelegate = self
self.physicsBody?.velocity = CGVectorMake(0, 0)
self.anchorPoint = CGPoint(x: 0, y: 0.20)
backgroundColor = SKColor(red: 81.0/255.0, green: 192.0/255.0, blue: 201.0/255.0, alpha: 1.0)
self.Enemy1 = SKNode()
addChild(Enemy1)
SpawnPlayer()
SpawnEnemy(CGPoint(x: self.frame.size.width / 2, y: Platform1.position.y + 15))
SpawnEnemy(CGPoint(x: self.frame.size.width / 2, y: Platform2.position.y + 15))
//Same code for all the other Platforms.
}
func SpawnEnemy(position: CGPoint!){
switch (arc4random_uniform(3)){
case 0:
Picture1.filteringMode = .Nearest
Picture2.filteringMode = .Nearest
Animation1 = SKAction.animateWithTextures([Picture1,Picture2], timePerFrame: 0.5)
AnimationRepeat1 = SKAction.repeatActionForever(Animation1)
Sprite1 = SKSpriteNode (imageNamed: "Sprite1.png")
Sprite1.size = CGSize(width: 64, height: 64)
Sprite1.zPosition = 2
Sprite1.physicsBody = SKPhysicsBody(rectangleOfSize: CGSize(width: 45, height: 50))
Sprite1.physicsBody?.dynamic = true
Sprite1.physicsBody?.allowsRotation = false
Sprite1.physicsBody?.restitution = 0.0
Sprite1.physicsBody?.usesPreciseCollisionDetection = true
Sprite1.physicsBody?.categoryBitMask = EnemyCategory
Sprite1.physicsBody?.collisionBitMask = PlayerCategory | Platform1Category
Sprite1.physicsBody?.contactTestBitMask = Wall1Category | Wall2Category | PlayerCategory
Sprite1.runAction(AnimationRepeat1)
Enemy.position = position
Enemy.addChild(Sprite1)
case 1:
Picture3.filteringMode = .Nearest
Picture4.filteringMode = .Nearest
Animation1 = SKAction.animateWithTextures([Picture3,Picture4], timePerFrame: 0.5)
AnimationRepeat1 = SKAction.repeatActionForever(Animation1)
Sprite2 = SKSpriteNode (imageNamed: "Sprite2.png")
Sprite2.size = CGSize(width: 64, height: 64)
Sprite2.zPosition = 2
Sprite2.physicsBody = SKPhysicsBody(rectangleOfSize: CGSize(width: 45, height: 50))
Sprite2.physicsBody?.dynamic = true
Sprite2.physicsBody?.allowsRotation = false
Sprite2.physicsBody?.restitution = 0.0
Sprite2.physicsBody?.usesPreciseCollisionDetection = true
Sprite2.physicsBody?.categoryBitMask = EnemyCategory
Sprite2.physicsBody?.collisionBitMask = PlayerCategory | Platform1Category
Sprite2.physicsBody?.contactTestBitMask = Wall1Category | Wall2Category | PlayerCategory
Sprite2.runAction(AnimationRepeat1)
Enemy.position = position
Enemy.addChild(Sprite2)
case 2:
Picture5.filteringMode = .Nearest
Picture6.filteringMode = .Nearest
Animation1 = SKAction.animateWithTextures([Picture5,Picture6], timePerFrame: 0.5)
AnimationRepeat1 = SKAction.repeatActionForever(Animation1)
Sprite3 = SKSpriteNode (imageNamed: "Sprite3.png")
Sprite3.size = CGSize(width: 64, height: 64)
Sprite3.zPosition = 2
Sprite3.physicsBody = SKPhysicsBody(rectangleOfSize: CGSize(width: 45, height: 50))
Sprite3.physicsBody?.dynamic = true
Sprite3.physicsBody?.allowsRotation = false
Sprite3.physicsBody?.restitution = 0.0
Sprite3.physicsBody?.usesPreciseCollisionDetection = true
Sprite3.physicsBody?.categoryBitMask = EnemyCategory
Sprite3.physicsBody?.collisionBitMask = PlayerCategory | Platform1Category
Sprite3.physicsBody?.contactTestBitMask = Wall1Category | Wall2Category | PlayerCategory
Sprite3.runAction(AnimationRepeat1)
Enemy.position = position
Enemy.addChild(Sprite3)
default:
return
}
}

Answer 1

The reason you're only seeing one position is that you're only creating one "enemy" and moving it around with SpawnEnemy. Since your sprites are all added to the same "enemy", they will all show up wherever your enemy was moved to last.
Let's chop down what your code is to the relevant bits:
var Enemy: SKNode!
override func didMoveToView(view: SKView) {
self.Enemy1 = SKNode()
addChild(Enemy1)
SpawnEnemy(CGPoint(x: self.frame.size.width / 2, y: Platform1.position.y + 15))
SpawnEnemy(CGPoint(x: self.frame.size.width / 2, y: Platform2.position.y + 15))
}
func SpawnEnemy(position: CGPoint!){
switch (arc4random_uniform(3)){
case 0:
Enemy.position = position
Enemy.addChild(Sprite1)
case 1:
Enemy.position = position
Enemy.addChild(Sprite2)
case 2:
Enemy.position = position
Enemy.addChild(Sprite3)
default:
return
}
}
So, in didMoveToView(), you create one Enemy node. Then, as you call SpawnEnemy, you do a bunch of stuff to add other sprites, but as far as Enemy is concerned, you're just changing its position. Since you're adding the sprites to the same node, when you move that Enemy node, the child sprites move with it, too.
You have two options to fix this. Either add your sprites to some higher-level node (like the scene), or create new "enemy" nodes for each of the sprites you intend to add. Either should work, but the best choice will depend on what you're trying to accomplish with them - the scope of that discussion is beyond what you're talking about here.