How can I get the number of skspritenodes in a scene? - ios

I want to find out what the number of nodes is in a scene. For example, I want to create an if statement so that if the number of nodes in the scene is 0 or any other number, I would call a function.
This is what i have done but it only calls the function the first time children.count is 0 but ignores the other times.
I am not removing or adding any sprite nodes anywhere else in my code.
func dot(){
var dotTexture = SKTexture (imageNamed: "dot")
dotTexture.filteringMode = SKTextureFilteringMode.Nearest
var dot = SKSpriteNode(texture: dotTexture)
dot.setScale(0.5)
dot.position = CGPoint(x: self.frame.size.width * 0.5 , y: self.frame.size.height * 1.1)
dot.physicsBody = SKPhysicsBody (circleOfRadius: dot.size.height/2.0)
dot.physicsBody?.dynamic = true
dot.physicsBody?.allowsRotation = false
self.addChild(dot)
println("done")
}
override func update(currentTime: CFTimeInterval) {
/* Called before each frame is rendered */
if children.count == 0 {
dot()
println("dot")
}
}

if you're doing this inside the scene itself you can do
if (self.children.count == x) {
yourFunction() //call your function
}
or
if (children.count == x) {
yourFunction() //call your function
}
in response to your comment:
there's an update method that runs every frame in sprite kit. Use it like this:
override func update(currentTime: CFTimeInterval) {
/* Called before each frame is rendered */
if (children.count == x) {
yourFunction() //call your function
}
}

use this:
if (self.children.count == someNumber) {
<#enter code here#>
}
where some number is a trigger number or expression.
Objective-C, use:
if ([self children].count == someNumber) {
// enter code here
}
Also, where it says "enter code here," call your function and do what you need to do.

I want to find out what the number of nodes is in a scene
Use this method:
func nodeCount(scene:SKScene) -> Int {
return scene[".//*"].count
}
This will give you the count of all nodes in the entire scene heirarchy.

Related

moving platform with gameplay kit

Creating a 2d game, and want to add moving platforms where I can control the pattern and rotation of the platform.
Example:
I want this platform to move in a clockwise motion, also when it reaches the top and bottom I want it to rotate accordingly as if it is facing the direction it is going (so the platform would essentially rotate 180 degrees as it arches at the top and bottom).
I can't use SKActions because I need the physics to work properly.
My idea is that I can use an Agent with behaviors and goals to do this. Not sure if I will need path finding as well.
I'm researching how to use these features, but the documentation and lack of tutorials is hard to decipher. I'm hoping someone could save my some time of trial and error by providing an example of how this would work.
Thanks in advance!
Using SKActions or adjusting the position manually will be sucky to get working the way you want, BUT it's always worth a shot to give it a go, since it would take 2 minutes to mock it up and see...
I'd suggest doing something like a Path class that sends velocity commands to the platform every frame ...
Actually, this could be a good exercise in learning the state machine..
MOVE RIGHT STATE: if X position > starting position X + 200, enter state "move down"
MOVE DOWN STATE: if Y position < starting position Y - 200, enter state "move left"
MOVE LEFT STATE: if X position < starting position X, enter state "move up"
MOVE UP STATE: if Y position > starting position Y, enter state "move right"
.. there are ways you could figure out to give it more curvature instead of just straight angle (when changing direction)
Otherwise you would have to translate that into a class / struct / component and give each platform it's own instance of it.
///
Another option is to take the physics out of the equation, and create a playerIsOnPlatform property... then you manually adjust the position of the player each frame... (or maybe a SKConstraint)
This would then require more code on jumping and such, and turns things to spaghetti pretty quickly (last time I tried it)
But, I was able to successfully clone this, using proper hit detection going that route:
https://www.youtube.com/watch?v=cnhlFZeIR7Q
UPDATE:
Here is a working project:
https://github.com/fluidityt/exo2/tree/master
Boilerplate swift stuff:
import SpriteKit
import GameplayKit
// Workaround to not having any references to the scene off top my head..
// Simply add `gScene = self` in your didMoveToViews... or add a base scene and `super.didMoveToView()`
var gScene = GameScene()
class GameScene: SKScene {
override func didMove(to view: SKView) {
gScene = self
}
var entities = [GKEntity]()
var graphs = [String : GKGraph]()
private var lastUpdateTime : TimeInterval = 0
func gkUpdate(_ currentTime: TimeInterval) -> TimeInterval {
if (self.lastUpdateTime == 0) {
self.lastUpdateTime = currentTime
}
let dt = currentTime - self.lastUpdateTime
for entity in self.entities {
entity.update(deltaTime: dt)
}
return currentTime
}
override func update(_ currentTime: TimeInterval) {
self.lastUpdateTime = gkUpdate(currentTime)
}
}
Here is the very basic component:
class Platforms_BoxPathComponent: GKComponent {
private enum MovingDirection: String { case up, down, left, right }
private var node: SKSpriteNode!
private var state: MovingDirection = .right
private lazy var startingPos: CGPoint = { self.node.position }()
#GKInspectable var startingDirection: String = "down"
#GKInspectable var uniqueName: String = "platform"
#GKInspectable var xPathSize: CGFloat = 400
#GKInspectable var yPathSize: CGFloat = 400
// Moves in clockwise:
private var isTooFarRight: Bool { return self.node.position.x > (self.startingPos.x + self.xPathSize) }
private var isTooFarDown: Bool { return self.node.position.y < (self.startingPos.y - self.yPathSize) }
private var isTooFarLeft: Bool { return self.node.position.x < self.startingPos.x }
private var isTooFarUp: Bool { return self.node.position.y > self.startingPos.y }
override func didAddToEntity() {
print("adding component")
// can't add node here because nodes aren't part of scene yet :(
// possibly do a thread?
}
override func update(deltaTime seconds: TimeInterval) {
if node == nil {
node = gScene.childNode(withName: uniqueName) as! SKSpriteNode
// for some reason this is glitching out and needed to be redeclared..
// showing 0 despite clearly not being 0, both here and in the SKS editor:
xPathSize = 300
}
let amount: CGFloat = 2 // Amount to move platform (could also be for for velocity)
// Moves in clockwise:
switch state {
case .up:
if isTooFarUp {
state = .right
fallthrough
} else { node.position.y += amount }
case .right:
if isTooFarRight {
state = .down
fallthrough
} else { node.position.x += amount }
case .down:
if isTooFarDown {
state = .left
fallthrough
} else { node.position.y -= amount }
case .left:
if isTooFarLeft {
state = .up
fallthrough
} else { node.position.x -= amount }
default:
print("this is not really a default, just a restarting of the loop :)")
node.position.y += amount
}
}
}
And here is what you do in the sks editor:

Finish action running on a SpriteNode without disabling touches

i have a player who's physicsBody is divided to parts (torso, legs, head, ect), now i have a button on screen that control the movement of the player, if the button is pressed to the right the player moves to the right, and that part works fine. the problem is every time the movement changes the walk() method is called and what it does is animate the player legs to look like its walking, but if the movement doesn't stop then is keeps calling the walk() without it finishing the animation, so it looks like its stuck back and forth. what i am trying to achieve is for the player to be able to walk constantly but for the walk() (animation method) to be called once, finish, then called again(as long as the button to walk is still pressed). here what i have so far:
func walk(){
let leftFootWalk = SKAction.run {
let action = SKAction.moveBy(x: 1, y: 0.1, duration: 0.1)
let actionReversed = action.reversed()
let seq = SKAction.sequence([action, actionReversed])
self.leftUpperLeg.run(seq)
self.leftLowerLeg.run(seq)
}
let rightFootWalk = SKAction.run {
let action = SKAction.moveBy(x: 0.4, y: 0.1, duration: 0.1)
let actionReversed = action.reversed()
let seq = SKAction.sequence([action, actionReversed])
self.rightUpperLeg.run(seq)
self.rightLowerLeg.run(seq)
}
let group = SKAction.sequence([leftFootWalk, SKAction.wait(forDuration: 0.2), rightFootWalk])
run(group)
}
extension GameScene: InputControlProtocol {
func directionChangedWithMagnitude(position: CGPoint) {
if isPaused {
return
}
if let fighter = self.childNode(withName: "fighter") as? SKSpriteNode, let fighterPhysicsBody = fighter.physicsBody {
fighterPhysicsBody.velocity.dx = position.x * CGFloat(300)
walk()
if position.y > 0{
fighterPhysicsBody.applyImpulse(CGVector(dx: position.x * CGFloat(1200),dy: position.y * CGFloat(1200)))
}else{
print("DUCK") //TODO: duck animation
}
}
}
First of all you can use SKAction.runBlock({ self.doSomething() })
as the last action in your actions sequence instead of using completion.
About your question, you can use hasAction to determine if your SKNode is currently running any action, and you can use the key mechanism for better actions management.
See the next Q&A
checking if an SKNode is running a SKAction
I was able to solve this, however i'm still sure there is a better approach out there so if you know it be sure to tell. here is what i did:
first i added a Boolean called isWalking to know if the walking animation is on(true) or off(false) and i set it to false. then i added the if statement to call walk() only if the animation is off(false) and it sets the boolean to on(true).
func directionChangedWithMagnitude(position: CGPoint) {
if isPaused {
return
}
if let fighter = self.childNode(withName: "fighter") as? SKSpriteNode, let fighterPhysicsBody = fighter.physicsBody {
fighterPhysicsBody.velocity.dx = position.x * CGFloat(300)
print(fighterPhysicsBody.velocity.dx)
if !isWalking{
isWalking = true
walk()
}
}
}
and i changed walk() to use completions blocks and set the Boolean to off(false) again
func walk(){
let walkAction = SKAction.moveBy(x: 5, y: 5, duration: 0.05)
let walk = SKAction.sequence([walkAction, walkAction.reversed()])
leftUpperLeg.run(walk) {
self.rightUpperLeg.run(walk)
}
leftLowerLeg.run(walk) {
self.rightLowerLeg.run(walk, completion: {
self.isWalking = false
})
}
}

Removing a sprite in an if statement with SpriteKit

I want to make a game where every time a user touches, it switches between one of two "states". In order to keep track of touches, I made a variable called userTouches, which changes from true to false each time a user touches. I want to make it so that if numberOfTouches is true, it updates the texture to state0; if it's false, it updates the texture to state1. Pretty much just toggling between state0 and state1 for each touch.
var userTouches: Bool = true
override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {
/* Called when a touch begins */
for touch in (touches as! Set<UITouch>) {
userTouches = !userTouches
}
let centered = CGPoint(x: size.width/2, y: size.height/2)
let state0 = SKTexture(imageNamed:"state0")
let state1 = SKTexture(imageNamed:"state1")
var activeState: SKSpriteNode = SKSpriteNode(texture: state0)
//Add new state0 if it's odd, remove old state0 if it's not.
if userTouches == true {
activeState.texture = state0
println("IT'S TRUE")
} else {
activeState.texture = state1
println("IT'S FALSE")
}
self.addChild(activeState)
activeState.name = "state0"
activeState.xScale = 0.65
activeState.yScale = 0.65
activeState.position = centered
}
When I run the code, the new textures are added according to the conditions, but the old ones are still there. They are being added as new spritenodes in the scene. I do not want this. I was expecting it to simply switch between the textures (state0 and state1) of the activeState spritenode depending on my boolean variable. How can I have my code toggle between textures each time a user taps, instead of piling new spritenodes on top of one another?
Each time you create a new object, change its texture (a new object`s texture, but not the texture of object which was set up last time) and add it to the scene. That's why new objects are added and nothing happens with the old objects.
Do this and it will solve your problem:
Create textures and SKSpriteNode object outside the touchesBegan function
If you have no init at your scene, create SKSpriteNode object at didMoveToView function for example and add it to scene
Then in touchesBegan function only set texture to SKSpriteNode object
it would look something like this:
class GameScene: SKScene {
...
let state0 = SKTexture(imageNamed:"state0")
let state1 = SKTexture(imageNamed:"state1")
var activeState: SKSpriteNode?
...
override func didMoveToView(view: SKView) {
let centered = CGPoint(x: size.width/2, y: size.height/2)
activeState = SKSpriteNode(texture: state0)
self.addChild(activeState!)
activeState!.name = "state0"
activeState!.xScale = 0.65
activeState!.yScale = 0.65
activeState!.position = centered
}
...
override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {
if userTouches {
activeState!.texture = state0
} else {
activeState!.texture = state1
}
}
...
}

removing all nodes in existence

In my game, I have a method bringing down sprites. When the user loses (gameStarted == false) , I need a way to remove all these nodes I've brought into the scene. I've tried to remove these nodes two ways, by simply saying ball.removeFromParent(), and also using the removeBalls function at the bottom. Both methods stopped future balls from entering the scene, but didn't remove the ones already in existence. If anybody has a way of doing this, I'd really appreciate it.
override func didMoveToView(view: SKView) {
var create = SKAction.runBlock({() in self.createTargets()})
var wait = SKAction.waitForDuration(2)
var createAndWaitForever = SKAction.repeatActionForever(SKAction.sequence([create, wait])
self.runAction(createAndWaitForever)
}
func createTargets() {
ball = SKSpriteNode(imageNamed:"blueBlue")
let randomx = Int(arc4random_uniform(370) + 165)
ball.position = CGPoint(x: randomx, y: 1400)
addChild(ball)
let moveDown = SKAction.moveBy(CGVector(dx: 0, dy: -1300), duration: 7)
if gameStarted == false {
ball.removeAllActions()
ball.removeFromParent()
removeBalls([ball])
}
if gameStarted && spawnReady {
ball.runAction(moveDown)
if ball.parent == nil {
addChild(ball)
}
}
}
func removeBalls(balls : [SKSpriteNode]) {
for ball in balls {
ball.removeFromParent()
}
}
Where are you keeping track of each ball? Do you have a balls array?
Do this:
Give a name to your ball nodes, say "ball"
Enumerate
Swift
self.enumerateChildNodesWithName("ball", usingBlock: {
(node: SKNode!, stop: UnsafeMutablePointer <ObjCBool>) -> Void in
node.removeFromParent()
})
Obj-C
[self enumerateChildNodesWithName:#"ball" usingBlock:^(SKNode *node, BOOL *stop) {
[node removeFromParent];
}];`

iOS Spritekit intersectsnode does not work for SKShapeNode

I am using the iOS SpriteKit Game Swift template on iOS8.3. I am trying to use the function func intersectsNode(_ node: SKNode) -> Bool to detect overlap of two circles created as SKShapeNodes. Turns out the function does not detect the intersection if its SKShapeNodes. But on further troubleshooting, it turns out the function works if I use the default Spaceship sprite of the template. Here is the code which works:
override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {
/* Called when a touch begins */
for touch in (touches as! Set<UITouch>) {
let location = touch.locationInNode(self)
let sprite = SKSpriteNode(imageNamed:"Spaceship")
sprite.xScale = 0.3
sprite.yScale = 0.3
sprite.position = location
self.circles.append(sprite)
self.addChild(sprite)
if circles.count == 1 {
println("One circle")
} else {
for var index = 0; index < circles.count-1; ++index {
if sprite.intersectsNode(circles[index]) {
println(circles[index].frame)
println("Circle intersects another")
}
}
}
}
}
When two sprites overlap in the above code the function returns YES and prints the intersection string. Here is the code which does NOT work:
override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {
/* Called when a touch begins */
for touch in (touches as! Set<UITouch>) {
let location = touch.locationInNode(self)
let sprite = SKShapeNode(circleOfRadius: 50)
sprite.position = location
self.circles.append(sprite)
self.addChild(sprite)
if circles.count == 1 {
println("One circle")
} else {
for var index = 0; index < circles.count-1; ++index {
if sprite.intersectsNode(circles[index]) {
println(circles[index].frame)
println("Circle intersects another")
}
}
}
}
}
As you can see the code blocks are completely identical except in one case its an SKSpriteNode and the other case its SKShapeNode. I also printed the frames of the SKShapeNode Circles and I can see they have have valid frames. So I am puzzled by this as I would like to use SKShapeNodes in my code for now but I cannot use the intersectNode function as it does not work.
The documentation for intersectsNode says this:
The two nodes are considered to intersect if their frames intersect. The children of both nodes are ignored in this test.
Which means you won't get the result you want when using circles.
However, checking if two circles overlap is as easy as checking if the distance between their centers is less than the sum of their radiuses.

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