I'm having an issue with using a particle emitter with reference nodes.
It works when it's referenced directly in the scene (for example, inside the GameScene.sks file), but it doesn't work when it's referenced within another .sks file, and that file/node is then referenced in GameScene.sks, although other referenced nodes appear correctly.
Here's the hierarchy:
GameScene.sks
- Reference Node to RocketFire.sks (emitter) <-- works
- Reference Node to Rocket.sks
Rocket.sks
- Reference Node to RocketFire.sks (emitter) <-- doesn't work in GameScene
- Reference Node to Engine.sks (non-emitter nodes) <-- works in GameScene
RocketFire.sks (SpriteKit particle file)
Engine.sks (SpriteKit scene file with non-emitter nodes)
Is there the wrong way to use Reference Nodes or particle emitters?
(Let me know if more info is needed)
EDIT:
I actually made it work some of the time. Sometimes it would suddenly start working when I remove and re-add the referenced nodes in all the files, or if I change the node hierarchy. But still, I can't identify a consistent reason for when it works and when it doesn't, because since changing it and putting it back to when it worked, doesn't fix it. (Feels like a bug, honestly)
The problem is that since iOS 10 all sprite nodes are by default paused. This includes your scene. It is not enough to just make your scene not paused (isPaused = false) you have to make the children not paused as well.
for your example I added to smoke emitters to my plane.sks file which is dragged onto my GameScene.sks file as an SKReferenceNode
and in my Plane.swift file, note I've put isPaused = false on one of the emitters and it still doesn't work
var leftSmoke: SKEmitterNode!
var rightSmoke: SKEmitterNode!
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
setup()
}
func setup() {
if let leftSmoke = self.childNode(withName: "//leftSmoke") as? SKEmitterNode {
self.leftSmoke = leftSmoke
leftSmoke.isPaused = false
}
if let rightSmoke = self.childNode(withName: "//rightSmoke") as? SKEmitterNode {
self.rightSmoke = rightSmoke
}
}
the plane with the scene running (no emitters)
set the plane object to not paused (inside Plane.swift)
func setup() {
self.isPaused = false
if let leftSmoke = self.childNode(withName: "//leftSmoke") as? SKEmitterNode {
self.leftSmoke = leftSmoke
leftSmoke.isPaused = false
}
if let rightSmoke = self.childNode(withName: "//rightSmoke") as? SKEmitterNode {
self.rightSmoke = rightSmoke
}
}
and voila
FYI
It probably works intermittently for you because you might have a break point set. Whenever you have a breakpoint set and the code stops it unPauses nodes automatically
Related
I have an ARKit app that uses SpriteKit to display SKNodes that correspond to ARAnchors in the AR session. I am using the ARSKViewDelegate method
func view(_ view: ARSKView, nodeFor anchor: ARAnchor) -> SKNode?
to display the nodes. This works for nodes I create and return in that method, but I have some more complicated nodes that I would like to design in an .sks file and then display for some anchors. When I return a node instantiated from an .sks file in that method the app crashes with an error saying the node is already in the scene (if the node is in the .sks file for the current scene), or already has a parent (if it is in an .sks file for a different scene).
How can I display sprites in ARKit that are drawn in an .sks file?
Try this approach:
if let view = self.view as! SKView? {
if let scene = SKScene(fileNamed: "mySpriteKitScene") {
guard let clone = scene.childNode(withName: "myRedSprite")?
.copy() as? SKSpriteNode
else { return }
clone.name = "mySecondRedSprite"
clone.position.x += 250
clone.physicsBody = SKPhysicsBody()
scene.addChild(clone)
view.presentScene(scene)
}
}
Recently, I decided to apply my previous knowledge in C++ and Python to learning Swift. After which, I decided to see what I could do with the SceneKit framework. After hours of checking through the documentation, and consulting a tutorial, I have to wonder what's going wrong with my code:
class GameViewController: UIViewController {
var gameView:SCNView!
var gameScene:SCNScene!
var cameraNode:SCNNode!
override func viewDidLoad() {
super.viewDidLoad()
initScene()
initView()
initCamera()
}
func initView() {
//initialize the game view - this view holds everything else in the game!
gameView = self.view as! SCNView
//allow the camera to move to gestures - mainly for testing purposes
gameView.allowsCameraControl = true
//use default lighting while still practicing
gameView.autoenablesDefaultLighting = true
}
func initScene() {
//initialize the scene
gameScene = SCNScene()
//set the scen in the gameView object to the scene created by this function
gameView.scene = gameScene
}
func initCamera() {
//create a node that will become the camera
cameraNode = SCNNode()
//since a node can be any object in the scene, this needs to be set up as a camera
cameraNode.camera = SCNCamera()
cameraNode.position = SCNVector3 (x:0, y:5, z:15)
}
}
After more checking through the documentation and making sure that I was now copying from the tutorial directly to get it to work, I still have no luck with this. According to a lot of the other questions I found here on StackOverflow, it looks like it has something to do with the forced unwrapping, the exclamation points, but I'm not exactly sure why that is.
I've probably been staring the answer in the face combing through this documentation, but I'm not quite seeing what the problem is.
Also, apologies if my comments are a bit long and/or distracting.
You have the following problems:
1) you should re-order the initializations in your viewDidLoad, doing so:
initView() // must be initialized before the scene
initScene() // you have been crashing here on getting `gameView.scene`, but gameView was nil
initCamera()
2) cameraNode is not attached on the rootNode, so you may add the following code at the end of initCamera:
gameScene.rootNode.addChildNode(cameraNode)
I have ready many (if not all) articles on SO and other sites about the disasters of dealing with SpriteKit and memory issues. My problem, as many others have had, is after i leave my SpriteKit scene barely any of the memory added during the scene session is released. I've tried to implement all suggested solutions in the articles i've found, including, but not limited to...
1) Confirm the deinit method is called in the SKScene class.
2) Confirm no strong references to the parent VC in the scene class.
3) Forcefully remove all children and actions, and set the scene to nil when the VC disappears. (Setting the scene to nil was what got the deinit method to eventually get called)
However, after all of that, memory still exists. Some background, this app goes between standard UIKit view controllers and a SpriteKit scene (it's a professional drawing app). As an example, the app is using around 400 MB before entering a SpriteKit scene. After entering the scene and creating multiple nodes, the memory grows to over 1 GB (all fine so far). When i leave the scene, the memory drops maybe 100 MB. And if i re-enter the scene, it continues to pile on. Are there any ways or suggestions on how to completely free all memory that was used during a SpriteKit session? Below is a few of the methods being used to try and fix this.
SKScene class
func cleanScene() {
if let s = self.view?.scene {
NotificationCenter.default.removeObserver(self)
self.children
.forEach {
$0.removeAllActions()
$0.removeAllChildren()
$0.removeFromParent()
}
s.removeAllActions()
s.removeAllChildren()
s.removeFromParent()
}
}
override func willMove(from view: SKView) {
cleanScene()
self.removeAllActions()
self.removeAllChildren()
}
Presenting VC
var scene: DrawingScene?
override func viewDidLoad(){
let skView = self.view as! SKView
skView.ignoresSiblingOrder = true
scene = DrawingScene(size: skView.frame.size)
scene?.scaleMode = .aspectFill
scene?.backgroundColor = UIColor.white
drawingNameLabel.text = self.currentDrawing?.name!
scene?.currentDrawing = self.currentDrawing!
scene?.drawingViewManager = self
skView.presentScene(scene)
}
override func viewDidDisappear(_ animated: Bool) {
if let view = self.view as? SKView{
self.scene = nil //This is the line that actually got the scene to call denit.
view.presentScene(nil)
}
}
As discussed in the comments, the problem is probably related to a strong reference cycle.
Next steps
Recreate a simple game where the scene is properly deallocated but some of the nodes are not.
I'll reload the scene several time. You'll see the scene is properly deallocated but some nodes into the scene are not. This will cause a bigger memory consumption each time we replace the old scene with a new one.
I'll show you how to find the origin of the problem with Instruments
And finally I'll show you how to fix the problem.
1. Let's create a game with a memory problem
Let's just create a new game with Xcode based on SpriteKit.
We need to create a new file Enemy.swift with the following content
import SpriteKit
class Enemy: SKNode {
private let data = Array(0...1_000_000) // just to make the node more memory consuming
var friend: Enemy?
override init() {
super.init()
print("Enemy init")
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
deinit {
print("Enemy deinit")
}
}
We also need to replace the content of Scene.swift with the following source code
import SpriteKit
class GameScene: SKScene {
override init(size: CGSize) {
super.init(size: size)
print("Scene init")
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
print("Scene init")
}
override func didMove(to view: SKView) {
let enemy0 = Enemy()
let enemy1 = Enemy()
addChild(enemy0)
addChild(enemy1)
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
let newScene = GameScene(size: self.size)
self.view?.presentScene(newScene)
}
deinit {
print("Scene deinit")
}
}
As you can see the game is designed to replace the current scene with a new one each time the user taps the screen.
Let's start the game and look at the console. Will' see
Scene init
Enemy init
Enemy init
It means we have a total of 3 nodes.
Now let's tap on the screen and let's look again at the console
Scene init
Enemy init
Enemy init
Scene init
Enemy init
Enemy init
Scene deinit
Enemy deinit
Enemy deinit
We can see that a new scene and 2 new enemies have been created (lines 4, 5, 6). Finally the old scene is deallocated (line 7) and the 2 old enemies are deallocated (lines 8 and 9).
So we still have 3 nodes in memory. And this is good, we don't have memory leeks.
If we monitor the memory consumption with Xcode we can verify that there is no increase in the memory requirements each time we restart the scene.
2. Let create a strong reference cycle
We can update the didMove method in Scene.swift like follows
override func didMove(to view: SKView) {
let enemy0 = Enemy()
let enemy1 = Enemy()
// ☠️☠️☠️ this is a scary strong retain cycle ☠️☠️☠️
enemy0.friend = enemy1
enemy1.friend = enemy0
// **************************************************
addChild(enemy0)
addChild(enemy1)
}
As you can see we now have a strong cycle between enemy0 and enemy1.
Let's run the game again.
If now we tap on the screen and the look at the console we'll see
Scene init
Enemy init
Enemy init
Scene init
Enemy init
Enemy init
Scene deinit
As you can see the Scene is deallocated but the Enemy(s) are no longer removed from memory.
Let's look at Xcode Memory Report
Now the memory consumption goes up every time we replace the old scene with a new one.
3. Finding the issue with Instruments
Of course we know exactly where the problem is (we added the strong retain cycles 1 minute ago). But how could we detect a strong retain cycle in a big project?
Let click on the Instrument button in Xcode (while the game is running into the Simulator).
And let's click on Transfer on the next dialog.
Now we need to select the Leak Checks
Good, at this point as soon as a leak is detected, it will appear in the bottom of Instruments.
4. Let's make the leak happen
Back to the simulator and tap again. The scene will be replaced again.
Go back to Instruments, wait a few seconds and...
Here it is our leak.
Let's expand it.
Instruments is telling us exactly that 8 objects of type Enemy have been leaked.
We can also select the view Cycles and Root and Instrument will show us this
That's our strong retain cycle!
Specifically Instrument is showing 4 Strong Retain Cycles (with a total of 8 Enemy(s) leaked because I tapped the screen of the simulator 4 times).
5. Fixing the problem
Now that we know the problem is the Enemy class, we can go back to our project and fix the issue.
We can simply make the friend property weak.
Let's update the Enemy class.
class Enemy: SKNode {
private let data = Array(0...1_000_000)
weak var friend: Enemy?
...
We can check again to verify the problem is gone.
I have setup a SKScene to be used as an SKReferenceNode. The sled is an SKSpriteNode with a custom class defined in the reference node scene and all the dogs are children of the sled sprite. The custom class and using the reference node is all fine, my problem is i'm unable to "crop" the scene to only show N number of dogs. Its as if after dropping the reference node into another scene, that parent scene is ignoring the reference node's width/height parameters and just displaying everything in it. So the question is, is this possible? Or do SKReferenceNodes not adhere to the scene width and heights properties when used in a parent scene?
The first image is of the full view reference scene (70x425). Second image is of what the frame should look like when i change the height programmatically if I only want the bottom 2 dogs to be shown.
class SledTeam: SKSpriteNode {
var dogTeam = [Int]()
required init?(coder aDecoder: NSCoder) {
switch dogTeam.count {
case 7,8:
self.scene?.size.height = 425
break
case 5,6:
self.scene?.size.height = 335
break
case 3,4:
self.scene?.size.height = 260
break
case 1,2:
self.scene?.size.height = 190
break
default:
break
}
}
}
My gues is to use a invisible sprite node in your sks reference file with the size to contains all nodes.
After call this invisible "base" node and crop it.
To get the invisible node, you can use this extension:
extension SKReferenceNode {
func getBasedChildNode () -> SKNode? {
if let child = self.children.first?.children.first {return child}
else {return nil}
}
}
for other details see my old post:
Add SKReferenceNode/SKScene to another SKScene in SpriteKit
I have a game where Falling Nodes fall down and hit the Base Number Sprite Node and game logic is run from there. When I set up a new game from scratch the collision detection works exactly how it should. My problem occurs when I create a game from a previous save using NSCoding. In both cases (new game and continue from save game) the physics bodies are the same - dynamic, same size body, same contactTestBitMask, same categoryBitMask. I have tested all of this so I know it is true. The physics contact delegate is also set to the right object. In a game continued from a save, however, the contacts are not registered and I cannot figure out why. The only thing I can think of, but am unable to figure out is object which is set as my physics contact delegate and is the parent of the objects I want collision detection for gets loaded/unarchived without me actually calling decodeObjectForKey for it.
Any help would be much appreciated
func initBaseNumberSpritePhysicsBody() {
baseNumberSprite.physicsBody = nil
baseNumberSprite.physicsBody = SKPhysicsBody(rectangleOfSize: baseNumberSprite.size)
baseNumberSprite.physicsBody!.categoryBitMask = baseNumberCategory
baseNumberSprite.physicsBody!.contactTestBitMask = fallingNodeCategory
baseNumberSprite.physicsBody!.collisionBitMask = 0
baseNumberSprite.physicsBody!.usesPreciseCollisionDetection = true
baseNumberSprite.physicsBody!.allowsRotation = false
}
func initPhysicsBodyForFallingNode(node: NumberNode) {
node.physicsBody = nil
node.physicsBody = SKPhysicsBody(rectangleOfSize: node.size)
node.physicsBody!.categoryBitMask = fallingNodeCategory
node.physicsBody!.contactTestBitMask = baseNumberCategory
node.physicsBody!.collisionBitMask = 0
node.physicsBody!.allowsRotation = false
node.physicsBody!.velocity = nodeVelocity
}
func didBeginContact(contact: SKPhysicsContact) {
if isContactBetween(fallingNodeCategory, and: baseNumberCategory, contact: contact) {
handleContactBetweenFallingNodeAndBaseNumber(contact)
} else {
print("\nUNKNOWN CONTACT OCCURED\n")
}
updateInternalState()
checkGameOverCondition()
}
required init?(coder aDecoder: NSCoder) {
// gameZone = aDecoder.decodeObjectForKey(gameZoneKey) as! GameZone
super.init(coder: aDecoder)
gameZone = self.children[0] as! GameZone //Not decoded by itself but somehow decoded with the this GameScene Object (the "self" object here)
gameZone.delegate = self
self.physicsWorld.contactDelegate = gameZone
}
override func encodeWithCoder(aCoder: NSCoder) {
super.encodeWithCoder(aCoder)
aCoder.encodeObject(gameZone, forKey: gameZoneKey) //Gets coded
}
I was able to figure out my own problem here. A fundamental understanding I was lacking is the SKNodes encode their own child nodes.
// gameZone = aDecoder.decodeObjectForKey(gameZoneKey) as! GameZone
The gameZone object is a child node. So I was encoding it as well as other key objects twice which was leading to my problem. The problem was had nothing to do with the physics world contact delegate or encoding/decoding.