Change texture of individual nodes in didBeginContact - swift

I've created a simple game where I have a match hover over candles (the odd description lends itself to my question) and the player scores a point when the match comes in contact with the wick. However, if it comes into contact with the anything else (like the 'wax' part of the candle), the game is over. The player controls the match by tapping on the screen.
My candle, being the wick and the coloured part, is created as follows (I have removed irrelevant parts, like the series of random textures):
func makeCandles() {
//Node properties and randomisation
let candle = SKNode()
let randomCandle = Int(arc4random_uniform(UInt32(candleTexture.count)))
let randomTexture = candleTexture[randomCandle] as SKTexture
let random = arc4random_uniform(17)
candle.position = CGPoint(x: self.frame.size.width, y: CGFloat(random * 12) - 120)
//Candle
let chosenCandle = SKSpriteNode(texture: randomTexture)
chosenCandle.position = CGPoint(x: 0, y: self.frame.size.height / 2)
chosenCandle.physicsBody = SKPhysicsBody(rectangleOfSize: chosenCandle.size)
chosenCandle.physicsBody?.dynamic = false
chosenCandle.physicsBody?.categoryBitMask = self.candleCategory
chosenCandle.physicsBody?.contactTestBitMask = self.matchCategory
chosenCandle.physicsBody?.collisionBitMask = 0
chosenCandle.physicsBody?.restitution = 0
candle.addChild(chosenCandle)
//Wick
let wickArea = SKSpriteNode(texture: wickTexture)
wickArea.name = "wickNode"
wickArea.position = CGPoint(x: 0, y: self.frame.size.height / 1.3)
wickArea.physicsBody = SKPhysicsBody(rectangleOfSize: CGSize(width: wickArea.size.width / 4, height: wickArea.size.height))
wickArea.physicsBody?.dynamic = false
wickArea.physicsBody?.categoryBitMask = self.wickCategory
wickArea.physicsBody?.contactTestBitMask = self.matchCategory
wickArea.physicsBody?.collisionBitMask = 0
wickArea.zPosition = 11
wickArea.physicsBody?.restitution = 0
candle.addChild(wickArea)
//Add the node and zPosition
self.partsMoving.addChild(candle)
chosenCandle.zPosition = 12
}
The candles are then created in a runBlock:
let createCandles = SKAction.runBlock({() in self.makeCandles()})
let briefPause = SKAction.waitForDuration(averageDelay, withRange: randomDelay)
let createAndPause = SKAction.sequence([createCandles, briefPause])
let createAndPauseForever = SKAction.repeatActionForever(createAndPause)
self.runAction(createAndPauseForever)
This is my function that changes the texture which is called in didBeginContact:
func updateFlame() {
if let newNode: SKNode = self.childNodeWithName("//wickNode") {
let updateTexture = SKAction.setTexture(flameTexture, resize: true)
newNode.runAction(updateTexture)
}
}
This is my didBeginContact function:
func didBeginContact(contact: SKPhysicsContact) {
if contact.bodyA.categoryBitMask == wickCategory || contact.bodyB.categoryBitMask == wickCategory {
score += 1
scoreLabel.text = "\(score)"
updateFlame()
} else {
runGameOverScene()
}
My problem is that it only changes the first node to a flame, and doesn't change any others. Even if it is the second or third wick on which contact is detected, only the first created wick is changed (the first one that comes across the screen). I know that contact is being detected on each node and that that works fine, because the score updates every time the match comes into contact with a wick.
What am I doing wrong that is stopping the texture of each node that individually comes into contact with the match from changing? Everything else is working just fine, but this part has had me beat for a week and everything I've tried doesn't work. This is the closest I've gotten.

After much trial and error, I have finally figured out how to make each node change texture when contact occurs! This is my code for that part:
func didBeginContact(contact: SKPhysicsContact) {
let collision : UInt32 = (contact.bodyA.categoryBitMask | contact.bodyB.categoryBitMask)
if collision == (matchCategory | candleCategory | cakeCategory) {
runGameOverScene()
}
if (contact.bodyA.categoryBitMask == wickCategory) {
let newWick = contact.bodyA.node
let updateTexture = SKAction.setTexture(flameTexture, resize: true)
newWick!.runAction(updateTexture)
} else if (contact.bodyB.categoryBitMask == wickCategory) {
let newWick = contact.bodyB.node
let updateTexture = SKAction.setTexture(flameTexture, resize: true)
newWick!.runAction(updateTexture)
}
}
I followed the logic of this question (even though I wanted to set the texture, not remove it) and it worked perfectly: removeFromParent() Doesn't Work in SpriteKit.

Related

Spawn SKSpriteNode objects at random times

I am making a game where I would like to spawn obstacles at random times. The obstacles are going to make contact with the player.
Here the code that I have:
var obstacle : SKSpriteNode?
func createObstacles() {
let obstaclesArray = ["obstacle_1", "obstacle_2", "obstacle_3", "obstacle_4", "obstacle_5"]
let randomObs = obstaclesArray.randomElement()
let selectedTexture = SKTexture(imageNamed: randomObs!)
obstacle = SKSpriteNode(imageNamed: randomObs!)
obstacle?.physicsBody = SKPhysicsBody(texture: selectedTexture, size: selectedTexture.size())
obstacle?.position = CGPoint(x: scene!.size.width/2 + selectedTexture.size().width, y: -120)
obstacle?.zPosition = -15
if let obs = obstacle?.physicsBody {
obs.affectedByGravity = true
obs.allowsRotation = false
obs.isDynamic = true
obs.restitution = 0
obs.categoryBitMask = obstacleCategory
obs.collisionBitMask = floorCategory
obs.contactTestBitMask = heroCategory
}
addChild(obstacle!)
}
func spawnObstacles() {
let wait = SKAction.wait(forDuration: 1, withRange: 0.4)
let spawn = SKAction.run {
createObstacles()
}
let moveLeft = SKAction.moveBy(x: -scene!.size.width - obstacle.size.width - 10, y: 0, duration: 2)
let sequence = SKAction.sequence([wait, spawn, moveLeft, SKAction.removeFromParent()])
self.run(SKAction.repeatForever(sequence))
}
I read some a similar questions but the response is my same code but it is not working.
Spawning a Spritekit node at a random time
I also tried other way:
var randDelay = Double.random(in: 0.7 ..< 1.4)
DispatchQueue.main.asyncAfter(deadline: randDelay, execute: {
if self.canCreateObstacle == true {
self.spawnObstacle()
}})
But it is not working and everytime I restart the game it seems like the function is being called two times, if I restart the game a third time it is called 3 times and so on.
Anyone with a good and clean solution to spawn objects at random times?
Do not use DispatchQueue Set up a repeating sequential action using wait(forDuration:withRange:) like you previously had.
https://developer.apple.com/documentation/spritekit/skaction/1417760-wait
First, create a generic node used to spawn obstacles, then attach this generic node to the scene.
Finally assign the repeating sequential action to this node.
Boom, you are done.
The reason why you want to assign it to a random node is because you want to be able to give your game the opportunity to stop generating obstacles, plus you alter the speed property to make the node generate nodes faster or slower.
You also want to detach the spawning/waiting from the moving/destroying, because as of right now, your code is confused. You are saying move the scene left for 2 seconds, then wait a random amount of time to spawn the next enemy, but I think you are trying to just spawn enemies on a time interval and move the enemy to the left.
Your scene code should look something like this
class GameScene : SKScene{
let obstacleGenerator = SKNode()
func didMove(to: view){
let wait = SKAction.wait(forDuration: 1, withRange: 0.4)
let spawn = SKAction.run({createObstacles()})
let sequence = SKAction.sequence([wait, spawn])
obstacleGenerator.run(SKAction.repeatForever(sequence))
addChild(obstacleGenerator)
}
func createObstacles() {
let obstaclesArray = ["obstacle_1", "obstacle_2", "obstacle_3", "obstacle_4", "obstacle_5"]
let randomObs = obstaclesArray.randomElement()
let selectedTexture = SKTexture(imageNamed: randomObs!)
obstacle = SKSpriteNode(imageNamed: randomObs!)
obstacle.position = CGPoint(x: scene!.size.width/2 + selectedTexture.size().width, y: -120)
obstacle.zPosition = -15
let body = SKPhysicsBody(texture: selectedTexture, size: selectedTexture.size())
body.affectedByGravity = true
body.allowsRotation = false
body.isDynamic = true
body.restitution = 0
body.categoryBitMask = obstacleCategory
body.collisionBitMask = floorCategory
body.contactTestBitMask = heroCategory
obstacle.physicsBody = body
addChild(obstacle!)
let moveLeft = SKAction.moveBy(x: -scene!.size.width - obstacle.size.width - 10, y: 0, duration: 2)
let seq = SKAction.sequence([moveLeft,SKAction.removeFromParent()])
obstacle.run(seq)
}
}
Now as for your spawning increasing with each reset, you never post how you are resetting. I am going to assume you never remove the previous action upon reset, and this is why your rate increases. It is always better to just create a new GameScene instance when doing a reset.

How to move and rotate SCNode using ARKit and Gesture Recognizer?

I am working on an AR based iOS app using ARKit(SceneKit). I used the Apple sample code https://developer.apple.com/documentation/arkit/handling_3d_interaction_and_ui_controls_in_augmented_reality as base for this. Using this i am able to move or rotate the whole Virtual Object.
But i want to select and move/rotate a Child Node in Virtual object using user finger, similar to how we move/rotate the whole Virtual Object itself.
I tried the below two links but it is only moving the child node in particular axis but not freely moving anywhere as the user moves the finger.
ARKit - Drag a node along a specific axis (not on a plane)
Dragging SCNNode in ARKit Using SceneKit
Also i tried replacing the Virtual Object which is a SCNReferenceNode with SCNode so that whatever functionality present for existing Virtual Object applies to Child Node as well, it is not working.
Can anyone please help me on how to freely move/rotate not only the Virtual Object but also the child node of a Virtual Object?
Please find the code i am currently using below,
let tapPoint: CGPoint = gesture.location(in: sceneView)
let result = sceneView.hitTest(tapPoint, options: nil)
if result.count == 0 {
return
}
let scnHitResult: SCNHitTestResult? = result.first
movedObject = scnHitResult?.node //.parent?.parent
let hitResults = self.sceneView.hitTest(tapPoint, types: .existingPlane)
if !hitResults.isEmpty{
guard let hitResult = hitResults.last else { return }
movedObject?.position = SCNVector3Make(hitResult.worldTransform.columns.3.x, hitResult.worldTransform.columns.3.y, hitResult.worldTransform.columns.3.z)
}
To move an object:
Perform a hitTest to check where you have touched, and detect which plane you touched and get a position. Move your SCNNode to that position by changing the node.position value with an SCNVector3.
Code:
#objc func panDetected(recognizer: UIPanGestureRecognizer){
let hitResult = self.arSceneView.hitTest(loc, types: .existingPlane)
if !hitResult.isEmpty{
guard let hitResult = hitResult.last else { return }
self.yourNode.position = SCNVector3Make(hitResult.worldTransform.columns.3.x, hitResult.worldTransform.columns.3.y, hitResult.worldTransform.columns.3.z)
}
The above code is enough to move your node over a detected plane, anywhere you touch, and not just in a single axis.
Rotating a node according to your gesture is a very difficult task and I have worked on a solution for quite sometime, never reaching a perfect output.
But, I have come across this repository in GitHub which allows you to do just that with a very impressive result.
https://github.com/Xartec/ScreenSpaceRotationAndPan
The Swift version of the code you require to rotate your node using your gesture would be :
var previousLoc: CGPoint?
var touchCount: Int?
#objc func panDetected(recognizer: UIPanGestureRecognizer){
let loc = recognizer.location(in: self.view)
var delta = recognizer.translation(in: self.view)
if recognizer.state == .began {
previousLoc = loc
touchCount = recognizer.numberOfTouches
}
else if gestureRecognizer.state == .changed {
delta = CGPoint.init(x: 2 * (loc.x - previousLoc.x), y: 2 * (loc.y - previousLoc.y))
previousLoc = loc
if touchCount != recognizer.numberOfTouches {
return
}
var rotMatrix: SCNMatrix4!
let rotX = SCNMatrix4Rotate(SCNMatrix4Identity, Float((1.0/100) * delta.y), 1, 0, 0)
let rotY = SCNMatrix4Rotate(SCNMatrix4Identity, Float((1.0 / 100) * delta.x), 0, 1, 0)
rotMatrix = SCNMatrix4Mult(rotX, rotY)
let transMatrix = SCNMatrix4MakeTranslation(yourNode.position.x, yourNode.position.y, yourNode.position.z)
self.yourNode.transform = SCNMatrix4Mult(self.yourNode.transform, SCNMatrix4Invert(transMatrix))
let parentNoderanslationMatrix = SCNMatrix4MakeTranslation((self.yourNode.parent?.worldPosition.x)!, (self.yourNode.parent?.worldPosition.y)!, (self.yourNode.parent?.worldPosition.z)!)
let parentNodeMatWOTrans = SCNMatrix4Mult((self.yourNode.parent?.worldTransform)!, SCNMatrix4Invert(parentNoderanslationMatrix))
self.yourNode.transform = SCNMatrix4Mult(self.yourNode.transform, parentNodeMatWOTrans)
let camorbitNodeTransMat = SCNMatrix4MakeTranslation((self.arSceneView.pointOfView?.worldPosition.x)!, (self.arSceneView.pointOfView?.worldPosition.y)!, (self.arSceneView.pointOfView?.worldPosition.z)!)
let camorbitNodeMatWOTrans = SCNMatrix4Mult((self.arSceneView.pointOfView?.worldTransform)!, SCNMatrix4Invert(camorbitNodeTransMat))
self.yourNode.transform = SCNMatrix4Mult(self.yourNode.transform, SCNMatrix4Invert(camorbitNodeMatWOTrans))
self.yourNode.transform = SCNMatrix4Mult(self.yourNode.transform, rotMatrix)
self.yourNode.transform = SCNMatrix4Mult(self.yourNode.transform, camorbitNodeMatWOTrans)
self.yourNode.transform = SCNMatrix4Mult(self.yourNode.transform, SCNMatrix4Invert(parentNodeMatWOTrans))
self.yourNode.transform = SCNMatrix4Mult(self.yourNode.transform, transMatrix)
}
}

Inconsistent contact detection in Swift 3 using SpriteKit

I'm having an issue with contact detection in Swift 3 using SpriteKit. The contact detection is working...sometimes. It seems purely random as to when it fires and when it doesn't.
I have a yellow "bullet" that moves up on the screen to hit a red sprite named targetSprite. The desired behavior is to have the bullet removed when it hits the target, but sometimes it just passes through underneath.
I've found many questions about contact detection not working at all, but I haven't found any dealing with inconsistent detection.
What can I do to fix this?
Here's the code:
import SpriteKit
import GameplayKit
enum PhysicsCategory:UInt32 {
case bullet = 1
case sprite1 = 2
case targetSprite = 4
// each new value should double the previous
}
class GameScene: SKScene, SKPhysicsContactDelegate {
// Create sprites
let sprite1 = SKSpriteNode(color: SKColor.blue, size: CGSize(width:100,height:100))
let targetSprite = SKSpriteNode(color: SKColor.red, size: CGSize(width:100,height:100))
let bullet = SKSpriteNode(color: SKColor.yellow, size: CGSize(width: 20, height: 20))
// show the bullet?
var isShowingBullet = true
// Timers
//var timer:Timer? = nil
var fireBulletTimer:Timer? = nil
// set up bullet removal:
var bulletShouldBeRemoved = false
let bulletMask = PhysicsCategory.bullet.rawValue
override func didMove(to view: SKView) {
// Physics
targetSprite.physicsBody = SKPhysicsBody(rectangleOf: targetSprite.centerRect.size)
targetSprite.physicsBody?.affectedByGravity = false
bullet.physicsBody = SKPhysicsBody(rectangleOf: bullet.centerRect.size)
bullet.physicsBody?.affectedByGravity = false
// Contact Detection:
targetSprite.physicsBody?.categoryBitMask = PhysicsCategory.targetSprite.rawValue
targetSprite.physicsBody?.contactTestBitMask =
//PhysicsCategory.sprite1.rawValue |
PhysicsCategory.bullet.rawValue
targetSprite.physicsBody?.collisionBitMask = 0 // no collision detection
// bullet physics
bullet.physicsBody?.categoryBitMask = PhysicsCategory.bullet.rawValue
bullet.physicsBody?.contactTestBitMask =
PhysicsCategory.targetSprite.rawValue
bullet.physicsBody?.collisionBitMask = 0 // no collision detection
// execute once:
fireBulletTimer = Timer.scheduledTimer(timeInterval: 1,
target: self,
selector: #selector(self.fireBullet),
userInfo: nil,
repeats: false)
// Add sprites to the scene:
self.addChild(sprite1)
self.addChild(bullet)
self.addChild(targetSprite)
// Positioning
targetSprite.position = CGPoint(x:0, y:300)
// Note: bullet and sprite1 are at 0,0 by default
// Delegate
self.physicsWorld.contactDelegate = self
}
func didBegin(_ contact: SKPhysicsContact) {
print("didBegin(contact:))")
//let firstBody:SKPhysicsBody
// let otherBody:SKPhysicsBody
// Use 'bitwise and' to see if both bits are 1:
if contact.bodyA.categoryBitMask & bulletMask > 0 {
//firstBody = contact.bodyA
//otherBody = contact.bodyB
print("if contact.bodyA....")
bulletShouldBeRemoved = true
}
else {
//firstBody = contact.bodyB
//otherBody = contact.bodyA
print("else - if not contacted?")
}
/*
// Find the type of contact:
switch otherBody.categoryBitMask {
case PhysicsCategory.targetSprite.rawValue: print(" targetSprite hit")
case PhysicsCategory.sprite1.rawValue: print(" sprite1 hit")
case PhysicsCategory.bullet.rawValue: print(" bullet hit")
default: print(" Contact with no game logic")
}
*/
} // end didBegin()
func didEnd(_ contact: SKPhysicsContact) {
print("didEnd()")
}
func fireBullet() {
let fireBulletAction = SKAction.move(to: CGPoint(x:0,y:500), duration: 1)
bullet.run(fireBulletAction)
}
func showBullet() {
// Toggle to display or not, every 1 second:
if isShowingBullet == true {
// remove (hide) it:
bullet.removeFromParent()
// set up the toggle for the next call:
isShowingBullet = false
// debug:
print("if")
}
else {
// show it again:
self.addChild(bullet)
// set up the toggle for the next call:
isShowingBullet = true
// debug:
print("else")
}
}
override func update(_ currentTime: TimeInterval) {
// Called before each frame is rendered
if bulletShouldBeRemoved {
bullet.removeFromParent()
}
}
}
Sorry for the inconsistent indentation, I can't seem to find an easy way to do this...
EDIT:
I have found that using 'frame' instead of 'centerRect' makes the collision area the size of the sprite. For example:
targetSprite.physicsBody = SKPhysicsBody(rectangleOf: targetSprite.centerRect.size)
should be:
targetSprite.physicsBody = SKPhysicsBody(rectangleOf: targetSprite.frame.size)
First advice - Do not use NSTimer (aka Timer) in SpriteKit. It is not paired with a game loop and can cause different issues in a different situations. Read more here ( answer posted by LearnCocos2D)
So, do this:
let wait = SKAction.wait(forDuration: 1)
run(wait, completion: {
[unowned self] in
self.fireBullet()
})
What I have noticed is that if I run your code in Simulator, I get the behaviour you have described. didBegin(contact:) is being fired randomly. Still, this is not happening on a device for me, and device testing is what matters.
Now, when I have removed Timer and did the same thing with SKAction(s) everything worked, means contact were detected every time.
Have you tried adding
.physicsBody?.isDynamic = true
.physicsBody?.usesPreciseCollisionDetrction =true
SpriteKit physics engine will calculate collision correctly if you do following:
1) set "usesPreciseCollisionDetection" property to true for bullet's physics body. This will change collision detection algorithm for this body. You can found more information about this property here, chapter "Working with Collisions and Contacts".
2) move your bullet using applyImpulse or applyForce methods. Collision detection will not woking correctly if you move body by changing it's position manually. You can find more information here, chapter "Making Physics Bodies Move".

SpriteKit having trouble removing nodes from scene

I have a method that creates a object that moves across the screen, and i run this method a lot of times to produce a lot of objects, but what i can't do now is remove them when i need to. I've tried
childNodeWithName("monster")?.removeFromParent()
but that doesn't work, they still complete their action. This is the method
func spawn() {
let ran = Int(arc4random_uniform(1400));
var monster = SKSpriteNode(imageNamed: "spike")
monster = SKSpriteNode(texture: text)
monster.position = CGPoint(x: ran, y: 800);
monster.zPosition = 1;
monster.physicsBody = SKPhysicsBody(texture: text, size: text.size())
monster.physicsBody?.categoryBitMask = PhysicsCategory.Monster
monster.physicsBody?.contactTestBitMask = PhysicsCategory.Player
monster.physicsBody?.collisionBitMask = 0
monster.physicsBody?.dynamic = false
monster.name = "monster"
self.addChild(monster);
let move = SKAction.moveTo(CGPointMake(monster.position.x, -100), duration: 1.5);
let remove = SKAction.runBlock { () -> Void in
monster.removeFromParent()
self.score += 1
}
monster.runAction(SKAction.sequence([move,remove]))
}
How can i remove every "monster" node at once when i need to?
To remove every monster node at once you can use SKNode's enumerateChildNodesWithName:usingBlock: method, like this:
self.enumerateChildNodesWithName("monster") {
node, stop in
node.removeAllActions()
node.removeFromParent()
}
Here, self is a scene because you've added monsters to the scene. If you for example added monsters to some container node, then you should run this method on that node, eg. containerNode.enumerateChildNodesWithName("monster"){...}

Why is there multiple collision calls Sprite Kit Swift

I am building an iOS swift game with collision. The hero is being bombarded by small stars coming from the right side of the screen. Every time a star hits the hero, the score is iterated and the star is removed. But, more than one point is added to the score.
Node Set-up:
var star = SKSpriteNode(imageNamed: "star")
star.size = CGSizeMake(30, 30)
star.zPosition = 10
var starPhysicsRect = CGRectMake(star.position.x - star.frame.size.width / 2, star.position.y - star.frame.size.width / 2, star.frame.size.width, star.frame.size.height)
star.physicsBody = SKPhysicsBody(edgeLoopFromRect: starPhysicsRect)
star.physicsBody?.restitution = 0
star.name = "star"
star.physicsBody?.mass = 0
return star
didBeginContact Function:
func didBeginContact(contact: SKPhysicsContact) {
//collision variables
var firstBodyNode = contact.bodyA.node as! SKSpriteNode
var secondBodyNode = contact.bodyB.node as! SKSpriteNode
var firstNodeName = firstBodyNode.name
var secondNodeName = secondBodyNode.name
//other variables
var scoreLabel: SKLabelNode = constantsInstance.scoreLabel(position: CGPointMake(self.frame.size.width * 0.86, self.frame.size.height * 0.928))
//check if hero hit star
if firstNodeName == "hero" && secondNodeName == "star" {
println("star hit")
secondBodyNode.removeFromParent()
//iterate score
childNodeWithName("scoreLabel")?.removeFromParent()
scoreLabel.text = "\(counterForScore)"
counterForScore++
self.addChild(scoreLabel)
}
}
I get "star hit" printed to the console several times as well. Why would the didBeginContact function be called more than once if I remove the star on the first call of the function?
I have run simulations on a smaller scale and found that the star goes fairly deep into the hero (because of the SKAction), if there is no remove command. Could it be that the didBeginContact function is called many times while the star is going into the hero and before it is removed?
All help is greatly appreciated.
You can check if parent of the SKSpriteNode is nil before continuing.
func didBeginContact(contact: SKPhysicsContact) {
var firstBodyNode : SKSpriteNode!
var secondBodyNode : SKSpriteNode!
// Assuming that the contact test bit mask of star is greater than hero. If it's not you should reverse the condition.
if contact.bodyA.contactTestBitMask < contact.bodyB.contactTestBitMask {
firstBodyNode = contact.bodyA.node as! SKSpriteNode
secondBodyNode = contact.bodyB.node as! SKSpriteNode
} else {
firstBodyNode = contact.bodyB.node as! SKSpriteNode
secondBodyNode = contact.bodyA.node as! SKSpriteNode
}
var firstNodeName = firstBodyNode.name
var secondNodeName = secondBodyNode.name
if firstNodeName == "hero" && secondNodeName == "star" {
if secondBodyNode.parent != nil {
// Your code.
}
}
}
Could it possibly be due to the physicsBody:
var star = SKSpriteNode(imageNamed: "star")
star.size = CGSizeMake(30, 30)
star.zPosition = 10
var starPhysicsRect = CGRectMake(star.position.x - star.frame.size.width / 2, star.position.y - star.frame.size.width / 2, star.frame.size.width, star.frame.size.height)
star.physicsBody = SKPhysicsBody(edgeLoopFromRect: starPhysicsRect)
Have a look at the logic creating the starPhysicsRect:
(star.position.x - star.frame.size.width / 2, star.position.y - star.frame.size.width / 2, star.frame.size.width, star.frame.size.height)
From what I can see this translates to the following values:
(-15, -15, 30, 30) those negative position-coordinates seem odd. Are you sure you don't just want: SKPhysicsBody(rectangleOfSize: star.size) ?