I get a nil exception error during runtime and I can not explain myself why there is a problem.
First I declare a SKSpriteNode Object like this
var destinationSign: SKSpriteNode?
and later I define a function that creates this SpriteNode like this
func showDestination( x: CGFloat, y: CGFloat){
destinationSign = SKSpriteNode(fileNamed: "sign_1")
destinationSign?.position.x = x
destinationSign?.position.y = y
addChild(destinationSign!)
}
after that I have a different function and triggers this showDestination function
showDestination(x: 20 , y: 40)
Does anyone have an explanation for this behaviour?
Thanks in advance
Looks like destinationSign is nil when addChild is called. You should double check the name of the image used to init it, capital letters, underscore, etc…
Try also:
if let node = destinationSign as SKSpriteNode {
self.addChild(node)
}
to prevent the nil exception (but remember the node will not be added)
You should also consider to use a more generalized function, that could be used in other contexts, as:
func show (_ node: SKSpriteNode, at point: CGPoint) {
node = SKSpriteNode(fileNamed: "sign_1")
if let node = node as SKSpriteNode {
node.position.x = point.x
node.position.y = point.y
addChild(node)
}
}
But these solution are merely theoretical, given the fact you actually want an error if your sprite is not added to the scene.
Related
I have run into this strange issue. I am adding an enemy(SKSpriteNode) from inside the GameScene didMove(to view: SKView) using addChild.
The enemy has been positioned to x:100, y: 100 and it appears correctly.
I also have another animation , the completion of which I am adding another enemy at the same location . But the enemy appears at a different location.The completion block is as shown below.
holeExplosion.runHoleExplosionAction {[unowned self] in
//self.addEnemy(enemyCount: 1, hole: holeExplosion)
var modEnemy: ParentEnemy? = nil
modEnemy = Enemy1(imageNamed: "Zombie1Jump1.png", healthPower:30)
print(" \(self.scene?.position.x) \(self.scene?.parent) ")
self.addChild(modEnemy!)
modEnemy!.enemySpeed = self.enemy1Speed
modEnemy!.name = "enemy1"
modEnemy!.position = CGPoint (x: 100 , y: 100)
modEnemy!.zPosition = 2
}
Any help would be appreciated. Thanks.
Your enemy class have physicsBody delegate?? maybe you can see that first because if it has it, you have to search your isDynamic property. You can't have 2 bodies in the same space when the property is equal to true.
I have less than 1 year using SpriteKit so I didn't use SKNodes as layers before until recently.
I have an SKNode layer that holds all of the fish and the user's position, for example:
var layerMainGame = SKNode()
layerMainGame.zPosition = 50
layerMainGame.addChild(userPosition)
layerMainGame.addChild(pipFish)
addChild(layerMainGame)
The interaction whether the user touched a fish or not is handled with this function, which is basically checking if their frames crossed:
if CGRectIntersectsRect(CGRectInset(node.frame, delta.dx, delta.dy), self.userPosition.frame) {
print("You got hit by \(name).")
gameOver()
}
It works. The interaction between the userPosition and pipFish works. What doesn't work is fish that are added as the game progresses. I have a function spawning different types of fish in intervals like this:
func spawnNew(fish: SKSpriteNode) {
layerMainGame.addChild(fish)
}
The interaction between the user and those fish that get added to the same layer later in the game does not work. I can pass right through them and no game over happens. When I completely remove the entire layerMainGame variable and just add them to the scene like normal, all the interactions work. Adding them all to the same SKNode layer doesn't work.
This is the function that creates a hit collision for every fish.
func createHitCollisionFor(name: String, GameOver gameOver: String!, delta: (dx: CGFloat, dy: CGFloat), index: Int = -1) {
enumerateChildNodesWithName(name) { [unowned me = self] node, _ in
if CGRectIntersectsRect(CGRectInset(node.frame, delta.dx, delta.dy), self.userPosition.frame) {
me.gameOverImage.texture = SKTexture(imageNamed: gameOver)
didGetHitActions()
me.runAction(audio.playSound(hit)!)
if index != -1 {
me.trophySet.encounterTrophy.didEncounter[index] = true
}
print("You got hit by \(name).")
}
}
}
And I call it like this:
createHitCollisionFor("GoldPiranha", GameOver: model.gameOverImage["Gold"], delta: (dx: 50, dy: 50), index: 1)
It works when the fish are not in the layer, but doesn't work when they are added to the layer.
When a node is placed in the node tree, its position property places it within a coordinate system provided by its parent.
Sprite Kit uses a coordinate orientation that starts from the bottom left corner of the screen (0, 0), and the x and y values increase as you move up and to the right.
For SKScene, the default value of the origin – anchorPoint is (0, 0), which corresponds to the lower-left corner of the view’s frame rectangle. To change it to center you can specify (0.5, 0.5)
For SKNode, the coordinate system origin is defined by its anchorPoint which by default is (0.5, 0.5) which is center of the node.
In your project you have layerMainGame added for example to the scene, his anchorPoint is by default (0.5,0.5) so the origin for the children like your fish is the center, you can see it if you change the fish positions like:
func spawnNew(fish: SKSpriteNode) {
layerMainGame.addChild(fish)
fish.position = CGPointZero // position 0,0 = parent center
}
Hope it help to understand how to solve your issue.
Update: (after your changes to the main question)
To help you better understand what happens I will give an example right away:
override func didMoveToView(view: SKView) {
var layerMainGame = SKNode()
addChild(layerMainGame)
let pipFish = SKSpriteNode(color: UIColor.yellowColor(), size: CGSizeMake(50,50))
pipFish.name = "son"
self.addChild(pipFish)
let layerPipFish = SKSpriteNode(color: UIColor.yellowColor(), size: CGSizeMake(50,50))
layerPipFish.name = "son"
layerMainGame.addChild(layerPipFish)
enumerateChildNodesWithName("son") { [unowned me = self] node, _ in
print(node)
}
}
Output:
Now I will simply change the line:
layerMainGame.addChild(layerPipFish)
with:
self.addChild(layerPipFish)
Output:
What happened?
As you can see enumerateChildNodesWithName written as your and my code print only childs directly added to self (because actually we launch enumerateChildNodesWithName which it is equal to launch self.enumerateChildNodesWithName )
How can I search in the full node tree?
If you have a node named "GoldPiranha" then you can search through all descendants by putting a // before the name. So you would search for "//GoldPiranha":
enumerateChildNodesWithName("//GoldPiranha") { [unowned me = self] ...
Let's say I have 10 nodes, where all of the nodes are the dots image, which are node1 thru node10. I create node1 as the following:
func createNode1() -> SKNode {
let spriteNode = SKNode()
spriteNode.position = CGPointMake(CGRectGetMidX(self.frame)/1.35, CGRectGetMidY(self.frame)/1.32)
let sprite = SKSpriteNode(imageNamed: "dot_1")
sprite.zPosition = 3.0
sprite.name = "A1_Dot"
spriteNode.addChild(sprite)
return spriteNode
}
I create the rest of nodes by creating 9 more functions, where next one would be as func createNode2etc, all the way up to 10 functions, where the only difference between them is node's name and its location. Basically each node has different location in the scene and of course different image name. Is there a way to load of the 10 nodes to the scene at once and manipulate node's locations at the time of use.? I'm looking for a way to load all 10 nodes to scene using a single function or method and assign node's positions within this same function. Thanks.
You need to use a loop to iterate through an array of positions, and move your code that adds the node to the scene into the loop:
let positions = [CGPointMake(CGRectGetMidX(self.frame)/1.35, CGRectGetMidY(self.frame)/1.32), ... /*add your 9 other positions here*/]
positions.enumerate().forEach { (index, point) in
let spriteNode = SKNode()
spriteNode.position = point
let sprite = SKSpriteNode(imageNamed: "dot_\(index + 1)")
sprite.zPosition = 3.0
sprite.name = "A\(index + 1)_Dot"
spriteNode.addChild(sprite)
// Add spriteNode to the scene here
}
You can either use a loop as Jugale suggested or you could just pass the values you want into the method
For example
func createNode1(imageNamed imageNamed: String, name: String, pos: CGPoint) -> SKNode {
let spriteNode = SKNode()
spriteNode.position = pos
let sprite = SKSpriteNode(imageNamed: imageNamed)
sprite.zPosition = 3.0
sprite.name = name
spriteNode.addChild(sprite)
return spriteNode
}
And now in your scene you can add the nodes like so
let node1Pos = ...
node1 = createNode1(imageNamed: "...", name: "A1_Dot", pos: node1Pos)
let node2Pos = ...
node2 = createNode1(imageNamed: "...", name: "A1_Dot", pos: node2Pos)
I am saying ImageNamed twice in the create Node function because when you pass stuff into functions Swift by default does not require the first description to be typed when calling the method. (see below)
So if would say imageNamed only once than you would call it like so.
node1 = createNode1("...", pos: node1Pos)
Also your creating node function could be simplified, unless you specifically want to return a SKNode in the method.
func createNode1(imageNamed imageNamed: String, name: String, pos: CGPoint) -> SKSpriteNode {
let sprite = SKSpriteNode(imageNamed: imageNamed)
sprite.position = pos
sprite.zPosition = 3.0
sprite.name = name
addChild(sprite)
return sprite
}
Either way is acceptable solution. Here are full details. In baseScene we create function createNodes and call that function in didMoveToView where nodeA1 is given position and added to the scene as shown below.
override func didMoveToView(view: SKView) {
let nodeA1Pos = CGPointMake(CGRectGetMidX(self.frame)/1.5, CGRectGetMidY(self.frame)/2.0)
nodeA1 = createNodes(imageNamed: "dot_1", name: "A1_Dot", pos: nodeA1Pos)
addChild(nodeA1)
}
Then in Level1Scene which is subclass of baseScene we just give a new position to nodeA1 which will override position originally set in baseScene:
override func didMoveToView(view: SKView) {
super.didMoveToView(view)
nodeA1.position = CGPointMake(CGRectGetMidX(self.frame)/1.3, CGRectGetMidY(self.frame)/0.67)
}
This way of subclassing saves a lot of time and code as only one function is used to generate all common sprite nodes.
All thanks to crashoverride777 !!!!
I faced a problem, when accessing an object I added to my scene within my collision detection:
Within my GamScene.swift on the top I declared
var passenger: PassengerNode!
And I trigger a spawnPassenger method, which is looking like this
func spawnPassenger(x: CGFloat, y: CGFloat){
let passenger = SKSpriteNode(imageNamed: "passenger")
passenger.position = CGPoint(x: platformArray[2].position.x, y: platformArray[2].position.y)
passenger.position.x = x
passenger.position.y = y
//passenger.physicsBody!.categoryBitMask = PhysicsCategory.Passenger
passenger.zPosition = 5
passenger.anchorPoint = CGPointZero
//print("passenger spawned")
self.addChild(passenger)
}
The App builds fine, but as soon as the collision is fired and this Action is triggered:
func actionPassengerOnboarding(){
let moveToTaxi = SKAction.moveTo(CGPoint(x: taxiNode.position.x, y: platformNode3.position.y), duration: 2);
let removePassenger = SKAction.removeFromParent()
let setPassengerToOnBoard = SKAction.runBlock({ () -> Void in
self.passengerOnBoard = true
})
let onBoardActionSequence = SKAction.sequence([moveToTaxi, removePassenger, setPassengerToOnBoard])
self.passenger.runAction(onBoardActionSequence, withKey: "isOnboarding")
}
is triggered I get a crash and a fatal error printed out fatal error: unexpectedly found nil while unwrapping an Optional value
(lldb)
Can anyone point me to my error? I just cant figure it out
Your error is the first line of your spawnPassenger function. You're making a new constant with let that has scope to that function. Instead of re-declaring a passenger variable, I think you're intending to set it to the class variable you made before. Remove the let and just say:
passenger = SKSpriteNode(imageNamed: "passenger")
This way, you're only referencing that one passenger variable and not making a new one with local scope.
I have a rectangle that needs to be constantly moving up, but is also declared globally like so so that I can call it in multiple places:
var obstacle = SKNode!
override func didMoveToView {
obstacle = rectangle()
}
func rectangle() -> SKNode {
let rect = SKSpriteNode(imageNamed: "Rectangle#x2")
rect.size = CGSizeMake(30, 30)
rect.position = CGPointMake(210, -250)
rect.physicsBody?.categoryBitMask = PhysicsCatagory.littleRect
rect.physicsBody?.contactTestBitMask = PhysicsCatagory.bigRect
rect.physicsBody?.collisionBitMask = 0
rect.physicsBody = SKPhysicsBody(rectangleOfSize: rect.size)
rect.physicsBody?.dynamic = true
rect.physicsBody?.affectedByGravity = false
rect.runAction(
SKAction.moveByX(0, y: 1200,
duration: NSTimeInterval(6.5)))
addChild(rect)
return rect
}
When I attempt to run it as an action repeating forever like so, i get the error "cannot convert value of type SKNode to argument runBlock" :
runAction(SKAction.repeatActionForever(
SKAction.sequence([
SKAction.runBlock(rectangle),
SKAction.waitForDuration(4.0)])))
So is there a way to declare this sort of action for a function set up like this? Thank you in advance.
First of all, this var obstacle = SKNode! will produce an error. You should declare an implicitly unwrapped optional like this:
var obstacle:SKNode!
About the main question (without analyzing the logic of what code actually does,)...You are passing an instance of SKNode class to +runBlock: method (which accepts a closure), thus the error. To fix this, you have to pass a closure, like this:
override func didMoveToView(view: SKView) {
runAction(SKAction.repeatActionForever(
SKAction.sequence([
SKAction.runBlock({[unowned self] in self.rectangle()}),
SKAction.waitForDuration(4.0)])))
}