I am using a CABasicAnimation that scales a CALayer repeatedly up and down. This means the animation is autoreversing, repeats infinity times, and it's key path is transform.scale.
What I want to do is "fade out" the animation at a certain point. So I don't want to stop it immediately (with layer.removeAnimationForKey:), but I want the animation to be smoothly removed in a time span of, say, one second. I have tried wrapping layer.removeAnimationForKey: in a CATransaction block and setting its animationDuration, but this did not work either.
Any help is appreciated.
Here is an example of a fade out, which is called when a video I playing with AVPlayer finishes.
override func viewWillAppear(animated: Bool) {
NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(ViewController.finishedPlaying(_:)), name: AVPlayerItemDidPlayToEndTimeNotification, object: playerItem)
}
var fadeOut:CABasicAnimation!
func finishedPlaying(myNotification:NSNotification) {
self.commsRightNow = commsMode.appleTV.rawValue
fadeOut = CABasicAnimation(keyPath: "opacity")
fadeOut.fromValue = 1.0
fadeOut.toValue = 0.0
fadeOut.duration = 8.0
fadeOut.delegate = self
fadeOut.setValue("video", forKey:"fadeOut")
fadeOut.removedOnCompletion = false
fadeOut.fillMode = kCAFillModeForwards
playerLayer.addAnimation(fadeOut, forKey: nil)
}
You can also call the method below to do additional actions when your animation completes. This one removes the AVPlayer object altogether. Note the keys fadeOut and video are user defined values and included since you may have multiple animations starting (&stopping) that you need to identify.
override func animationDidStop(anim: CAAnimation, finished flag: Bool) {
let nameValue = anim.valueForKey("fadeOut") as? String
if let name = nameValue {
if (name == "video") {
playerLayer?.removeFromSuperlayer()
}
}
You can also call this to be triggered when you animation starts.
override func animationDidStart(anim: CAAnimation) {
// Blah Blah
}
Related
My animation model has a total time interval of 45 seconds. I tap on the model and should be able to play it not right from the beginning, but from say, the 15th second.
Can anyone please help me out if you think by any means that this is possible?
EDIT:
As soon as I load my animation model, the SceneKit plays the animation. Now with the key in hand, I crop the animation with the help of a custom method I came across.
By tapping on the model, I enumerate through all the parent/child nodes to stop or remove animation from the scene. So far so good.
The problem appears when I try to add the cropped animation back on to the scene. Nothing really happens, as the scene remains idle without any action.
Am I doing something wrong here?
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
let touchLocation = touches.first!.location(in: sceneView)
// Let's test if a 3D Object was touch
var hitTestOptions = [SCNHitTestOption: Any]()
hitTestOptions[SCNHitTestOption.boundingBoxOnly] = true
let hitResults: [SCNHitTestResult] = sceneView.hitTest(touchLocation, options: hitTestOptions)
let animation = animScene?.entryWithIdentifier("myKey", withClass: CAAnimation.self)
print(" duration is...", animation!.duration)
let animationNew = subAnimation(of:(animation)!, startFrame: 10, endFrame: 360)
print("New duration is...", animationNew.duration)
sceneView.scene.rootNode.enumerateChildNodes { (node, stop) in
node.removeAllAnimations()
}
sceneView.scene.rootNode.enumerateChildNodes { (node, _) in
node.addAnimation(animationNew, forKey: "myKey")
}
}
Suppose, it's the most robust approach for playing animations containing in Collada file:
import SceneKit
func myAnimation(path: String) -> SCNAnimation? {
let scene = SCNScene(named: path)
var animation: SCNAnimationPlayer?
scene?.rootNode.enumerateChildNodes( { (child, stop) in
if let animationKey = child.animationKeys.first {
animation = child.animationPlayer(forKey: animationKey)
// variable pointee: ObjCBool { get nonmutating set }
stop.pointee = true
}
})
return animation?.animation
}
let node = SCNNode()
let animation = myAnimation(path: "animation.dae")
node.addAnimation(animation!, forKey: "FirstAnimationSet")
Seems my .dae file had a number of animations(with multiple id's) and they should be grouped as one. Once I group them together, I get control over the animation and could play them from whichever frame I want.
Let me preface this question by saying I know it has been asked a few times, but the most upvoted post here was from back in 2014 and the top answer doesn't seem to work anymore.
Issue
In my game, I have all my 'moving' nodes as children of pauseNode. When the pauses button is pressed or when the player leaves the app, pauseScene() is called:
func pauseScene() {
self.node.speed = 0
self.physicsWorld.speed = 0
self.node.isPaused = true
}
This pauses all sprite nodes and emitter nodes. This keeps the sprite nodes paused if the app transitions from background to foreground state, but the particle emitters seem to resume animating.
Current solution
I solved this issue by triggering pauseScene() after a small delay when the app became active.
override func didMove(to view: SKView) {
NotificationCenter.default.addObserver(self, selector: #selector(GameScene.applicationDidBecomeActive(notification:)), name: NSNotification.Name.UIApplicationDidBecomeActive, object: app)
}
#objc func applicationDidBecomeActive(notification: NSNotification) {
NSDelay(0.01) {
pauseScene()
}
}
func NSDelay(_ delay:Double, closure:#escaping ()->()) {
let when = DispatchTime.now() + delay
DispatchQueue.main.asyncAfter(deadline: when, execute: closure)
}
Goal
While this solution pauses the particles, it is not perfect because they are visible moving for the split second it takes to pause them again (this is the shortest delay that actually re-pauses them).
So, after reading the post I linked above, I tried to override applicationDidBecomeActive() in an SKView subclass as was suggested, but I couldn't get the method to be called. I want to prevent these particles from being unpaused in the first place, if possible. Thanks
So, it's been a little over a day and I've found a better solution. A comment in this post suggested having a variable that recorded the status of the scene, and updating it along with the pause/play functions:
var sceneIsPaused = false
func pauseScene() {
self.node.speed = 0
self.physicsWorld.speed = 0
self.node.isPaused = true
sceneIsPaused = true
}
func playScene() {
self.node.speed = 1
self.physicsWorld.speed = 1
self.node.isPaused = false
sceneIsPaused = false
}
Then, override SKView's update method and check the state of that variable. If the scene should be paused, pause it. This will mean that if the scene is automatically unpaused it will re-pause the next frame. This is much faster and cleaner than setting a delay:
override func update(_ currentTime: TimeInterval) {
if (sceneIsPaused == true) {
self.node.speed = 0
self.physicsWorld.speed = 0
self.node.isPaused = true
}
}
Desired behavior is: when an action is removed from a node (with removeAction(forKey:) for instance) it stops to animate and all the changes caused by action are discarded, so the node returns back to pervious state. In other words, I want to achieve behavior similar to CAAnimation.
But when a SKAction is removed, the node remains changed. It's not good, because to restore it's state I need to know exactly what action was removed. And if I then change the action, I also will need to update the node state restoration.
Update:
The particular purpose is to show possible move in a match-3 game. When I show a move, pieces start pulsating (scale action, repeating forever). And when the user moves I want to stop showing the move, so I remove the action. As the result, pieces may remain downscaled. Later I would like to add more fancy and complicated animations, so I want to be able to edit it easily.
Thanks to the helpful comment and answer I came to my own solution. I think the state machine would be bit too heavy here. Instead I created a wrapper node, which main purpose is run the animation. It also has a state: isAimating property. But, first of all, it allows to keep startAnimating() and stopAnimating() methods close to each other, incapsulated, so it's more difficult to mess up.
class ShowMoveAnimNode: SKNode {
let animKey = "showMove"
var isAnimating: Bool = false {
didSet {
guard oldValue != isAnimating else { return }
if isAnimating {
startAnimating()
} else {
stopAnimating()
}
}
}
private func startAnimating() {
let shortPeriod = 0.2
let scaleDown = SKAction.scale(by: 0.75, duration: shortPeriod)
let seq = SKAction.sequence([scaleDown,
scaleDown.reversed(),
scaleDown,
scaleDown.reversed(),
SKAction.wait(forDuration: shortPeriod * 6)])
let repeated = SKAction.repeatForever(seq)
run(repeated, withKey: animKey)
}
private func stopAnimating() {
removeAction(forKey: animKey)
xScale = 1
yScale = 1
}
}
Usage: just add everything that should be animated to this node. Works well with simple animations, like: fade, scale and move.
As #Knight0fDragon suggested, you would be better off using the GKStateMachine functionality, I will give you an example.
First declare the states of your player/character in your scene
lazy var playerState: GKStateMachine = GKStateMachine(states: [
Idle(scene: self),
Run(scene: self)
])
Then you need to create a class for each of these states, in this example I will show you only the Idle class
import SpriteKit
import GameplayKit
class Idle: GKState {
weak var scene: GameScene?
init(scene: SKScene) {
self.scene = scene as? GameScene
super.init()
}
override func didEnter(from previousState: GKState?) {
//Here you can make changes to your character when it enters this state, for example, change his texture.
}
override func isValidNextState(_ stateClass: AnyClass) -> Bool {
return stateClass is Run.Type //This is pretty obvious by the method name, which states can the character go to from this state.
}
override func update(deltaTime seconds: TimeInterval) {
//Here is the update method for this state, lets say you have a button which controls your character velocity, then you can check if the player go over a certain velocity you make it go to the Run state.
if playerVelocity > 500 { //playerVelocity is just an example of a variable to check the player velocity.
scene?.playerState.enter(Run.self)
}
}
}
Now of course in your scene you need to do two things, first is initialize the character to a certain state or else it will remain stateless, so you can to this in the didMove method.
override func didMove(to view: SKView) {
playerState.enter(Idle.self)
}
And last but no least is make sure the scene update method calls the state update method.
override func update(_ currentTime: TimeInterval) {
playerState.update(deltaTime: currentTime)
}
I'm animating a clock hand that takes a CGFloat value from 0 to 1. While I have the animation, I would like it to be a lot smoother. The total animation takes 5 seconds, as part of an input variable. How can I make this a lot smoother?
Ideally, I'd like to get all the values from 0 to 1 in 5 seconds...
The clock hand does a complete 360 but is a little choppy
#IBAction func start(_ sender: Any) {
timer = Timer.scheduledTimer(timeInterval: 0.1, target: self, selector: #selector(launchTimer), userInfo: nil, repeats: true)
launchTimer()
}
func launchTimer() {
guard seconds < 4.9 else {
timer.invalidate()
seconds = 0
return
}
seconds += 0.1
clockView.currentPressure = CGFloat(seconds / 5)
clockView.setNeedsDisplay()
}
EDIT
import UIKit
class GaugeView: UIView {
var currentPressure : CGFloat = 0.0
override func draw(_ rect: CGRect) {
StyleKitName.drawGauge(pressure: currentPressure)
}
}
Timer is not appropriate for animations on this scale. 100ms isn't a good step in any case, since it's not a multiple of the frame rate (16.67ms). Generally speaking, you shouldn't try to hand-animate unless you have a specialized problem. See UIView.animate(withDuration:...), which is generally how you should animate UI elements, allowing the system to take care of the progress for you.
For a slightly more manual animation, see CABasicAnimation, which will update a property over time. If you need very manual control, see CADisplayLink, but you almost never need this.
In any case, you must never assume that any timer is called precisely when you ask it to be. You cannot add 0.1s to a value just because you asked to be called in 0.1s. You have to look at what time it really is. Even hard-real-time systems can't promise something will be called at a precise moment. The best you can possibly get is a promise it will be within some tolerance (and iOS doesn't even give you that).
To animate this with UIView (which I recommend), it'll probably be something like:
#IBAction func start(_ sender: Any) {
self.clockView.currentPressure = 0
UIView.animate(withDuration: 5, animations: {
self.clockView.currentPressure = 1
})
}
With a CABasicAnimation (which is more complicated) it would be something like:
currentPressure = 1 // You have to set it to where it's going or it'll snap back.
let anim = CABasicAnimation(keyPath: "currentPressure")
anim.fromValue = 0
anim.toValue = 1
anim.duration = 5
clockView.addAnimation(anim)
Make the time interval smaller to make the animation smoother. That way it will seem like it's gliding around instead of jumping between values.
You can also use spritekit:
import SpriteKit
let wait = SKAction.wait(forDuration: 0.01)
let runAnim = SKAction.run {
launchTimer()
}
let n = SKNode()
n.run(SKAction.repeat(SKAction.sequence([wait, runAnim]), count: 500))
I am working on an interactive, animated scene. I want all touches on the scene to be disabled on entry. Then, once the objects (which are subclassed nodes) in the scene finish rotating/moving, I want to re-enable all touches on the screen to allow interaction. I have disabled user interaction using this code:
override func didMove(to view: SKView) {
setupNodes()
view?.isUserInteractionEnabled = false
spinLocations()
}
This is the code, within the scene file, for spinLocations:
func spinLocations() {
var allLocationArrays = [[String : CGPoint]]()
var previousArray = hiddenLocationPositions
for _ in 0...SearchConstant.numSpins {
let freshArray = generateNewLocationArray(previous: previousArray)
allLocationArrays.append(freshArray)
previousArray = freshArray
}
for (item, _) in hiddenLocationPositions {
let node = fgNode.childNode(withName: item) as! LocationNode
node.spin(position: allLocationArrays) // this is function below
}
hiddenLocationPositions = previousArray
}
This is the code for the animations in the node class:
func spin(position: [[String : CGPoint]]) {
var allActions = [SKAction]()
for array in position {
let action = SKAction.move(to: array[self.name!]!, duration: 2.0)
allActions.append(action)
}
let allActionsSeq = SKAction.sequence(allActions)
self.run(SKAction.sequence([SKAction.wait(forDuration: 5.0), allActionsSeq, SKAction.run {
self.position = position[position.count - 1][self.name!]!
},]))
}
This is the code for passing back the touches to the main scene from this class:
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
guard let parent = self.parent else { return }
}
As you can see, touch is not disabled here.
I do not want to add a "waitForDuration" SKAction to the runBlock to change the view status after the previous action; I want the program to determine when the animations are finished executing and then re-enable touches.
In order to do this, I theorised using a completion handler might work, but it only re-enables touches immediately (e.g. handling a handler to spin causes the touches to be detected again). Previously, I also tried to disable the view in the runBlock, but of course, that is run instantaneously. How do I ensure that the touches are re-detected following the animation without using "waitForDuration."?
So, this is a simple example that shows how you can:
1) Disable touches completely
2) Spin a node
3) When node is done with spinning, to enable touches
Here is the code (you can copy/paste it to try how it works):
class Object:SKSpriteNode{
func spin(times:Int,completion:#escaping ()->()) {
let duration = 3.0
let angle = CGFloat(M_PI) * 2.0
let oneRevolution = SKAction.rotate(byAngle: angle , duration: duration)
let spin = SKAction.repeat(oneRevolution, count: times)
let sequence = SKAction.sequence([spin,SKAction.run(completion)])
run(sequence, withKey:"spinning")
}
}
class WelcomeScene: SKScene {
override func didMove(to view: SKView) {
view.isUserInteractionEnabled = false
print("Touches Disabled")
let object = Object(texture: nil, color: .purple, size: CGSize(width: 200, height: 200))
addChild(object)
object.spin(times: 3, completion: {[weak self] in
self?.view?.isUserInteractionEnabled = true
print("Touches Enabled")
})
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
print("touch detected")
}
deinit {
print("Welcome scene deinited")
}
}
Here, you disable touches when scene is loaded, start spinning the object, and you pass a completion block to it... That block of code is used here:
let sequence = SKAction.sequence([spin,SKAction.run(completion)])
So after spinning, that block will be executed. Now, there are different ways to do this...Personally, I would use delegation, but I thought this can be less confusing... I can write an example for delegation too if needed, but basically, what you would do, is to set a scene as a delegate of your custom node, and notify it about spinning is done, so the scene can tell the view to re-enable the touches.