How do I spawn multiple nodes without them overlapping? - swift

Question

I have nodes spawning every 0.2-5.0 seconds on my screen like so:
override func didMoveToView(view: SKView) {
backgroundColor = UIColor.whiteColor()
runAction(SKAction.repeatActionForever(
SKAction.sequence([
SKAction.runBlock(blackDots),
SKAction.waitForDuration(1.0)])))
}
func random() -> CGFloat {
return CGFloat(Float(arc4random()) / 0xFFFFFFFF)
}
func random(min min: CGFloat, max: CGFloat) -> CGFloat {
return random() * (max - min) + min
}
func blackDots() {
let dot = SKSpriteNode(imageNamed: "first#2x")
dot.size = CGSizeMake(75, 75)
dot.name = "dotted"
dot.position = CGPointMake(500 * random(min: 0, max: 1), 500 * random(min: 0, max: 1))
addChild(dot)
}
However, when they are spawned, some intersect and lay on top of one another? Is there a way to prevent this? Thanks in advance.

Answer 1

Here's how to check if a node exists at a particular position.
You might want to throw the check into a loop so that if the position is taken, it will retry with a newly generated point. Otherwise you'll get some dots that just won't show. Just depends on what you're doing with them.
override func didMoveToView(view: SKView) {
backgroundColor = UIColor.whiteColor()
runAction(SKAction.repeatActionForever(
SKAction.sequence([
SKAction.runBlock(blackDots),
SKAction.waitForDuration(1.0)])))
}
func random() -> CGFloat {
return CGFloat(Float(arc4random()) / 0xFFFFFFFF)
}
func random(min min: CGFloat, max: CGFloat) -> CGFloat {
return random() * (max - min) + min
}
func blackDots() {
let dot = SKSpriteNode(imageNamed: "first#2x")
dot.size = CGSizeMake(75, 75)
dot.name = "dotted"
let position = CGPointMake(500 * random(min: 0, max: 1), 500 * random(min: 0, max: 1))
if positionIsEmpty(position) {
dot.position = position
addChild(dot)
}
}
func positionIsEmpty(point: CGPoint) -> Bool {
self.enumerateChildNodesWithName("dotted", usingBlock: {
node, stop in
let dot = node as SKSpriteNode
if (CGRectContainsPoint(dot.frame, point)) {
return false
}
})
return true
}

Answer 2

here is this in swift 3.1 please note that this did take me several hours to recreate successfully also a for-loop or TimerInterval won't run this properly it has to be a sequence of actions
like this
let wait = SKAction.wait(forDuration: 1)
let spawn = SKAction.run {
//be sure to call your spawn function here
example()
}
let sequence = SKAction.sequence([wait, spawn])
self.run(SKAction.repeatForever(sequence))
if this is done right it should work like I have it
func example() {
//the person node is equal to an SKSpriteNode subclass
person = people()
func random() -> CGFloat {
//this is the random spawn generator increasing or decreasing these two numbers will change how far or how close they spawn together
return CGFloat(Float(arc4random_uniform(UInt32(500 - 343))))
}
func random(min: CGFloat, max: CGFloat) -> CGFloat {
return random() * (max - min) + min
}
func spawnPeople() {
//note that this is set to spawn them on the x-axis but can easily be changed for the y-axis
let position = CGPoint(x: 2 * random(min: 0, max: 1),y: -290)
if positionIsEmpty(point: position) {
//set the position of your node and add it to the scene here any actions you want to add to the node will go here
person.position = position
self.addChild(person)
//example
person.run(parallax1)
}
}
func positionIsEmpty(point: CGPoint) -> Bool {
if (person.frame.contains(point)) {
print("failed")
return false
}
print("success")
return true
}
//make sure to call the spawn(name)() function down here or the code will not run
spawnPeople()
}
also I have all of this code in my didMoveToView function