I'm toying around with some SpriteKit things. I'm pretty new to SpriteKit so my techniques may be bad, I don't know. Here's what I'm working on:
It's basically a spaceship with shields (2D, viewed from above). There are several "shield segments" (left, right, top, bottom, each one is a SKShapeNode) and then there are "phaser" nodes which are lines drawn from the border to the center of the device (the spaceship is in the center). I want to detect when the phasers hit one of the shield segments. I tried this using collisionMasks but it didn't work at all. So I tried my own way of detecting.
Next, my method of drawing the phasers may seem odd. I searched online but haven't found anything, really. So the way I'm drawing the phaser is by constantly replacing the path of the phaser node(a straight line) with a slightly longer path, each frame.
That's the method that does this and also causes the app to crash:
incomingPhasers is an array containing all Phaser objects currently in the scene. The Phaser class mainly contains the SKShapeNode called node and some other meta information.
The advancement of the progress of the phaser is done by increasing the progressattribute by a bit. delta is the time difference since the last frame (as this method is being called from update(_:)
let vector is the displacement vector used for the line drawing.
private func advancePhasers(_ delta: TimeInterval) {
for phaser in incomingPhasers where !phaser.targetHit {
// advance progress of phaser
phaser.progress = min(phaser.progress + CGFloat(delta) * phaser.progressRate, 1)
let vector = phaser.origin.vector(toPoint: phaser.target, fraction: phaser.progress)
// create new path
let path = UIBezierPath()
path.move(to: phaser.origin)
path.addLine(to: phaser.origin + vector)
phaser.node.path = path.cgPath
// check collision
let phaserPoint = path.currentPoint
enumerateChildNodes(withName: "shieldSegment", using: { (node, stop) in
if let node = node as? ShieldSegmentNode {
if node.contains(phaserPoint) {
// collision
phaser.targetHit = true
}
}
})
}
}
enumerateChildNodes causes the app to crash when I add many phasers to the array:
* Terminating app due to uncaught exception 'NSGenericException', reason: '* Collection <__NSArrayM: 0x17404ce40> was mutated while being enumerated.'
I'm not sure what I can do here. I have to cycle through the shield segment nodes, but this keeps crashing.
Does this have something to do with thread safety? Do I need to make it thread safe? If so, how?
Thank you!
If you need any more information or code, tell me. I can't post everything here, it's way too much code.
You cannot mutate (change, add or remove items) in a collection while it is being enumerated. Hard to tell you more about how to fix it with out more details in your code. Some thing is mutating the collection in here:
enumerateChildNodes(withName: "shieldSegment", using: { (node, stop) in
if let node = node as? ShieldSegmentNode {
if node.contains(phaserPoint) {
// collision
phaser.targetHit = true
}
}
})
One way that I solve these problems is I have a second collection for putting items into that fit my desired criteria, then after the first enumeration, I can enumerate over the second collection and perform the necessary mutation to the first
Related
I'm implementing a mass-spring system (many small physics bodies joined together with SKPhysicsJointSpring instances) with SpriteKit. Some of the particles would get snagged while traversing the center of the scene.
There seems to be a small, static body in the middle of the scene and I don't know why it's there.
Here's an easy way to see what I'm talking about:
In XCode 8, create a brand new project with the "Game" template.
In GameViewController.viewDidLoad(), add view.showsPhysics = true
If you run the project, you should see a little dot in the middle, which is the errant body:
Anyone know how to get rid of it?
Edit: I tried to manually create the scene object:
In GameViewController.viewDidLoad(), I replaced this:
// Load the SKScene from 'GameScene.sks'
if let scene = SKScene(fileNamed: "GameScene") {
view.presentScene(scene)
}
with this:
let scene = GameScene(size: view.frame.size)
scene.anchorPoint = CGPoint(x: 0.5, y: 0.5)
view.presentScene(scene)
but that didn't fix it.
Anyways, I decided to make an answer because comments are not suitable due to lot of info I want to share. Also my answer, sadly, doesn't answer the question but it gives some useful info about this unidentified, obviously capable of flying (physics body) object :)
So this is the code how to grab it (and modify it???):
//you can use self.frame here...I just copied Alessandro's code
self.physicsWorld.enumerateBodies(in:(label?.frame)!) { body, stop in
if let node = body.node {
print("Type of this node: \(type(of:node))")
print("Frame of this node: \(node.frame))")
}else{
print("This body's node property is nil")
body.affectedByGravity = true
body.isDynamic = true
body.applyImpulse(CGVector(dx: 0.003, dy: 0.0003))
}
print("Area covered by this node physicsBody: \(body.area)")
}
So if you put a break point inside of that else statement, you can scan this physics body completely and get all the info about it, like that its node property is set to nil or that its isDynamic property is set to false. But you can change that, and like in my code, set for example isDynamics to true. This makes it moveable. So if you apply some forces to it, it will move.
Still, like I said in comments, I don't have an idea why it is there and what it represents or what is its purpose.
Also, for those who are wondering how it is possible that one physics body doesn't have a node associated with it ( body.node equals nil) but is still visible on screen when showsPhysics is set to true, there is a reasonable explanation. Physics world is separated from the node tree. So we can remove a sprite from a node tree, but that doesn't mean that its physics body will be removed instantly. It may happen that physics engine haven't finished simulation... So you probably wonder, how this might happen?
Let say you have three SKSpriteNode objects intersecting at the same time (say A contacts B and A contacts C at the same time). SpriteKit can process only one contact at time. And say that you are removing A from a parent when it is contacting with B. Then, there is a contact between A and C also, so didBegin:(_ contact) will be called twice. And if you remove A from its parent in first didBegin(_ contact) call, in the next didBegin(_ contact) call, bodyA.node will be nil (bodyA is a physics body of sprite A), but its physics body will remain visible until engine finishes what needed. This is because node tree and a physics world are separated.
About the "hello world" xCode game template , it seems a little physicsBody associated to the GameScene node.
With some code I've found this:
class GameScene: SKScene {
private var label : SKLabelNode?
private var spinnyNode : SKShapeNode?
override func didMove(to view: SKView) {
...
// End part of this function:
if let b = physicsWorld.body(in: (label?.frame)!) {
if let node = b.node {
print("Type of this node: \(type(of:node))")
print("Frame of this node: \(node.frame))")
}
print("Area covered by this node physicsBody: \(b.area)")
}
}
}
With a breakpoint to the last brace, you can see two bodies (maybe an array of bodies), one of them is the physicsBody to the left debugArea (array with index 1) with the same hex address as my body b in my code : 0x79794f90, a little rectangle body with area 4.444
Printing description of ((PKPhysicsBody *)0x79794f90):
<SKPhysicsBody> type:<Rectangle> representedObject:[<SKScene> name:'(null)' frame:{{-375, -667}, {750, 1334}} anchor:{0.5, 0.5}]
(lldb)
I had a similar problem. I have a game with two sprite nodes joined together (SKPhysicsJointFixed.joint) moving around an SKEditor created scene.
As per my design, this node-pair would impact a third sprite node and be propelled smoothly away from the third sprite node, EXCEPT when the impact was in the center of the scene. For the center of the scene impact, the node-pair would compress together while be propelled away from the third sprite node, presenting a poor graphical image.
After significant time debugging my code, I found this post. Kudos for the explanations and code. I can’t answer the “why” question but for the “particles would get snagged while traversing the center of the scene” question my suggested solution is to clear the collisionBitMask instead of moving the body.
BTW categoryBitMask is 0 when loaded.
//moves the problem offscreen unless it hits another node
//body.affectedByGravity = true
//body.isDynamic = true
//body.applyImpulse(CGVector(dx: 0.003, dy: 0.0003))
//
// collisionBitMask loads with 4294967295 = default value to collide with all categories
//
body.collisionBitMask = 0
I'm creating and adding a large number of SCNNodes to a SceneKit scene, which causes the app to freeze for a second or two.
I thought I could fix this by putting all the action in a background thread using DispatchQueue.global(qos: .background).async(), but no dice. It behaves exactly the same.
I saw this answer and put the nodes through SCNView.prepare() before adding them, hoping it would slow down the background thread and prevent blocking. It didn't.
Here's a test function that reproduces the problem:
func spawnNodesInBackground() {
// put all the action in a background thread
DispatchQueue.global(qos: .background).async {
var nodes = [SCNNode]()
for i in 0...5000 {
// create a simple SCNNode
let node = SCNNode()
node.position = SCNVector3(i, i, i)
let geometry = SCNSphere(radius: 1)
geometry.firstMaterial?.diffuse.contents = UIColor.white.cgColor
node.geometry = geometry
nodes.append(node)
}
// run the nodes through prepare()
self.mySCNView.prepare(nodes, completionHandler: { (Bool) in
// nodes are prepared, add them to scene
for node in nodes {
self.myRootNode.addChildNode(node)
}
})
}
}
When I call spawnNodesInBackground() I expect the scene to continue rendering normally (perhaps at a reduced frame rate) while new nodes are added at whatever pace the CPU is comfortable with. Instead the app freezes completely for a second or two, then all the new nodes appear at once.
Why is this happening, and how can I add a large number of nodes without blocking the main thread?
I don't think this problem is solvable using the DispatchQueue. If I substitute some other task instead of creating SCNNodes it works as expected, so I think the problem is related to SceneKit.
The answers to this question suggest that SceneKit has its own private background thread that it batches all changes to. So regardless of what thread I use to create my SCNNodes, they all end up in the same queue in the same thread as the render loop.
The ugly workaround I'm using is to add the nodes a few at a time in SceneKit's delegated renderer(_:updateAtTime:) method until they're all done.
I poked around on this and didn't solve the freeze (I did reduce it a bit).
I expect that prepare() is going to exacerbate the freeze, not reduce it, because it's going to load all resources into the GPU immediately, instead of letting them be lazily loaded. I don't think you need to call prepare() from a background thread, because the doc says it already uses a background thread. But creating the nodes on a background thread is a good move.
I did see pretty good performance improvement by moving the geometry outside the loop, and by using a temporary parent node (which is then cloned), so that there's only one call to add a new child to the scene's root node. I also reduced the sphere's segment count to 10 (from the default of 48).
I started with the spinning spaceship sample project, and triggered the addition of the spheres from the tap gesture. Before my changes, I saw 11 fps, 7410 draw calls per frame, 8.18M triangles. After moving the geometry out of the loop and flattening the sphere tree, I hit 60 fps, with only 3 draw calls per frame and 1.67M triangles (iPhone 6s).
Do you need to build these objects at run time? You could build this scene once, archive it, and then embed it as an asset. Depending on the effect you want to achieve, you might also consider using SCNSceneRenderer's present(_:with:incomingPointOfView:transition:completionHandler) to replace the entire scene at once.
func spawnNodesInBackgroundClone() {
print(Date(), "starting")
DispatchQueue.global(qos: .background).async {
let tempParentNode = SCNNode()
tempParentNode.name = "spheres"
let geometry = SCNSphere(radius: 0.4)
geometry.segmentCount = 10
geometry.firstMaterial?.diffuse.contents = UIColor.green.cgColor
for x in -10...10 {
for y in -10...10 {
for z in 0...20 {
let node = SCNNode()
node.position = SCNVector3(x, y, -z)
node.geometry = geometry
tempParentNode.addChildNode(node)
}
}
}
print(Date(), "cloning")
let scnView = self.view as! SCNView
let cloneNode = tempParentNode.flattenedClone()
print(Date(), "adding")
DispatchQueue.main.async {
print(Date(), "main queue")
print(Date(), "prepare()")
scnView.prepare([cloneNode], completionHandler: { (Bool) in
scnView.scene?.rootNode.addChildNode(cloneNode)
print(Date(), "added")
})
// only do this once, on the simulator
// let sceneData = NSKeyedArchiver.archivedData(withRootObject: scnView.scene!)
// try! sceneData.write(to: URL(fileURLWithPath: "/Users/hal/scene.scn"))
print(Date(), "queued")
}
}
}
I have an asteroid simulation with 10000 nodes and ran into this issue myself. What worked for me was creating the container node, then passing it to a background process to fill it with child nodes.
That background process uses an SCNAction on that container node to add each of the generated asteroids to the container node.
let action = runBlock {
Container in
// generate nodes
/// then For each node in generatedNodes
Container.addChildNode(node)
}
I also used a shared level of detail node with an uneven sided block as its geometry so that the scene can draw those nodes in a single pass.
I also pre-generate 50 asteroid shapes that get random transformations applied during the background generation process. That process simply has to grab at random a pregen block apply a random simd transformation then stored for adding scene later.
I’m considering using a pyramid for the LOD but the 5 x 10 x 15 block works for my purpose. Also this method can be easily throttled to only add a set amount of blocks at a time by creating and passing multiple actions to the node. Initially I passed each node as an action but this way works too.
Showing the entire field of 10000 still affects the FPS slightly by 10 a 20 FPS but At that point the container nodes own LOD comes into effect showing a single ring.
Add all of them when application started but position them where camera dont see. When you need them change their position where they should be.
I am trying to get the corner points from a still image using GPUImageHarrisCornerDetectionFilter.
I have looked at the example code from the project, I have looked at the documentation, and I have looked at this post that is about the same thing:
GPUImage Harris Corner Detection on an existing UIImage gives a black screen output
But I can't make it work - and I have a hard time understanding how this is supposed to work with still images.
What I have at this point is this:
func harrisCorners() -> [CGPoint] {
var points = [CGPoint]()
let stillImageSource: GPUImagePicture = GPUImagePicture(image: self.image)
let filter = GPUImageHarrisCornerDetectionFilter()
filter.cornersDetectedBlock = { (cornerArray:UnsafeMutablePointer<GLfloat>, cornersDetected:UInt, frameTime:CMTime) in
for index in 0..<Int(cornersDetected) {
points.append(CGPoint(x:CGFloat(cornerArray[index * 2]), y:CGFloat(cornerArray[(index * 2) + 1])))
}
}
filter.forceProcessingAtSize(self.image.size)
stillImageSource.addTarget(filter)
stillImageSource.processImage()
return points
}
This function always returns [] so it's obviously not working.
An interesting detail - I compiled the FilterShowcaseSwift project from GPUImage examples, and the filter fails to find very clear corners, like on a sheet of paper on a black background.
filter.cornersDetectedBlock = { (cornerArray:UnsafeMutablePointer<GLfloat>, cornersDetected:UInt, frameTime:CMTime) in
for index in 0..<Int(cornersDetected) {
points.append(CGPoint(x:CGFloat(cornerArray[index * 2]), y:CGFloat(cornerArray[(index * 2) + 1])))
}
}
This code you have here sets a block that gets called every frame.
This is an asynchronous process so when your function returns that has never been called yet and your array should always be empty. It should be called after the frame has finished processing.
To verify this, set a breakpoint inside that block and see if it gets called.
Warning from Brad Larson (creator of GPUImage) in the comments:
The GPUImage you create here stillImageSource will be deallocated after this function exits and may cause crashes in this case.
I am trying to blur multiple SKNode objects. I do this by having a parent SKEffectNode with a CIFilter set to #"CIGaussianBlur". Like so:
- (SKEffectNode *)createBlurNode
{
SKEffectNode *blurNode = [[SKEffectNode alloc] init];
blurNode.shouldRasterize = YES;
[blurNode setShouldEnableEffects:NO];
[blurNode setFilter:[CIFilter filterWithName:#"CIGaussianBlur"
keysAndValues:#"inputRadius", #10.0f, nil]];
return blurNode;
}
This works fine for a bunch of nodes currently onscreen. But when I space these notes far away from each other (about 3000 pixels), the blurring no longer happens and I get a big black box. This happens regardless of whether the SKNodes I'm blurring are SKShapeNodes or SKSpriteNodes. Here's a sample project with this issue: Sample Project. (By the way, thanks to BobMoff for the initial version found here):
Here's happy blur (when nodes are less than 3000 pixels away from each other):
Sad blur (when nodes are more than 3000 pixels away from each other):
UPDATE
This behavior occurs whenever an SKEffectNode is the parent. It doesn't matter if it's enabling effects, blurring, etc. If the parent node is an SKNode, it's fine. i.e. Even if the parent blur node is created like it is below, you will get the blackness:
- (SKEffectNode *)createBlurNode
{
SKEffectNode *blurNode = [[SKEffectNode alloc] init];
// blurNode.shouldRasterize = YES;
// [blurNode setShouldEnableEffects:NO];
// [blurNode setFilter:[CIFilter filterWithName:#"CIGaussianBlur"
// keysAndValues:#"inputRadius", #10.0f, nil]];
return blurNode;
}
I had a similar problem, with a very wide, panning scene that I wanted to blur.
To get the blur effect to work, I removed any nodes that were sticking out too far past the edges of the scene:
// Property declarations, elsewhere in the class:
var blurNode: SKEffectNode
var mainScene: SKScene
var exParents: [SKNode : SKNode] = [:]
/**
* Remove outlying nodes from the scene and activate the SKEffectNode
*/
func blurScene() {
let FILTER_MARGIN: CGFloat = 100
let widthMax: CGFloat = mainScene.size.width + FILTER_MARGIN
let heightMax: CGFloat = mainScene.size.height + FILTER_MARGIN
// Recursively iterate through all blurNode's children
blurNode.enumerateChildNodesWithName(".//*", usingBlock: {
[unowned self]
node, stop in
if node.parent != nil && node.scene != nil { // Ignore nodes we already removed
if let sprite = node as? SKSpriteNode {
// Calculate sprite node position in scene coordinates
let sceneOrig = sprite.scene!.convertPoint(sprite.position, fromNode: sprite.parent!)
// Find left, right, bottom and top edges of sprite
let l = sceneOrig.x - sprite.size.width*sprite.anchorPoint.x
let r = l + sprite.size.width
let b = sceneOrig.y - sprite.size.height*sprite.anchorPoint.y
let t = b + sprite.size.height
if l < -FILTER_MARGIN || r > widthMax || b < -FILTER_MARGIN || t > heightMax {
self.exParents[sprite] = sprite.parent!
sprite.removeFromParent()
}
}
}
})
blurNode.shouldEnableEffects = true
}
/**
* Disable blur and reparent nodes we removed earlier
*/
func removeBlur() {
self.blurNode.shouldEnableEffects = false
for (kid, parent) in exParents {
parent.addChild(kid)
}
exParents = [:]
}
NOTES:
This does remove content from your effect node, so extremely wide nodes won't show up in the final result:
You can see the mountain highlighted in red stuck out too far and was removed from the resulting blur.
This code only considers SKSpriteNodes. Empty SKNodes don't seem to break the effect node, but if you're using other visible nodes like SKShapeNodes or SKLabelNodes, you'll have to modify this code to include them.
If you have ignoreSiblingOrder = false, this code might mess up your z-ordering since you can't guarantee what order the nodes are added back to the scene.
Stuff I tried that didn't work
Simply saying node.hidden = true instead of using removeFromParent() doesn't work. That would be WAY too easy ;)
Using an SKCropNode to crop out outlying content didn't work for me. I tried having the SKEffectNode parent the SKCropNode and the other way around, but the black square appeared no matter how small I made the cropped area. This might still be worth looking into if you're desperate for a cleaner solution.
As noted here, SKScenes are secretly SKEffectNodes and you can set their filter just like our blurNode above. SKScenes don't show a black screen when their content is too big. Unfortunately, they seem to just silently disable the filter instead. Again, I might have missed something, so you could explore this option further if you're trying to apply an effect across the entire scene.
Alternate Solutions
You can capture an image of the whole screen and apply a filter to that, as suggested here. I ended up going with an even simpler solution; I took a generic screenshot of the stuff I wanted to blur, then applied a very heavy blur so you can't see the precise details. I used that as the blurred background and you can hardly tell it's not the real thing ;) This also saves a healthy chunk of memory and avoids a small UI hiccup.
Musings
This is a pretty nasty bug, and I hope Apple comes up with a solution soon. You can click this cute picture of a camera to get a GPU trace and some insight on what's happening:
The device seems to be discarding the framebuffer for the effect node because it takes up too much memory. This is affirmed by the fact that when there's more memory pressure on the device, it's easier to get the 'black square' on smaller content in the SKEffectNode.
I used a method that worked for my game but it requires the blurred area to be static without movement.
On iOS 10 using Swift 3 I used SKSpriteNode, SKView, SKEffectNode, CIFilter. I created a sprite from a texture returned from the SKView method "texture from node" and passed the current scene as the parameter because it inherits from SKNode. So essentially I was taking a "screenshot" of the scene and creating a sprite from it. I then put it in an SKEffectNode with a blur filter. (set "should rasterize" to true for better performance as I only needed to blur once). Finally I added the new sprite to the scene. From there you could add sprites to the scene and place them above the new blurred node.
let blurFilter = CIFilter(name: "CIGaussianBlur")!
let blurAmount = 15.0
blurFilter.setValue(blurAmount, forKey: kCIInputRadiusKey)
let blurEffect = SKEffectNode()
blurEffect.shouldRasterize = true
let screenshotNode = SKSpriteNode(texture: gameScene.view!.texture(from: gameScene))
blurEffect.addChild(screenshotNode)
blurEffect.filter = blurFilter
gameScene.addChild(blurEffect)
Possible workaround for the bug:
Use a camera, zoom WAY out, so you can see most everything of your background, take a screenshot style rendering of this image. Crop it to your needs, and then blur it. Then rasterise this.
Then scale this image back up, and slice it up if needs be, and place accordingly.
SKEffectNode renders into a texture. In most iOS systems the maximum size for a texture is 2048x2048. If an SKEffectNode is trying to render content larger than that, it will just use a 2048x2048 texture and anything outside of it will just not appear in the texture. It won't give you any error or warning about this happening; it simply does it silently.
And no, there is no way to tell SKEffectNode to use a texture of a specific size, and pan&clamp the content into it. It always uses a texture that will cover all the child nodes, and if the texture would be too large, it just silently uses that 2048x2048 texture.
I'm new to IOS and Swift, so I've started by porting Apple's Accelerometer example code to Swift.
This was all quite straightforward. Since the Accelerometer API has been deprecated, I used Core Motion instead, and it works just fine. I also switched to a storyboard.
The problem I have is that my layer delegate is only rarely called. It will go for a few minutes and never get called, and then it will get called 40 times a second, and then go back to not being called. If I context switch, the delegate will get called, and one of the sublayers will be displayed, but there are 32 sublayers, and I've yet to see them all get drawn. What's drawn seems to be fine - the problem is just getting the delegate to actually get called when I call setNeedsDisplay(), and getting all of the sublayers to get drawn.
I've checked to be sure that each sublayer has the correct bounds and frame dimensions, and I've checked to make sure that setNeedsDisplay() gets called after each accelerometer point is acquired.
If I attach an instrument, I see that the frame rate is usually zero, but occasionally it will be some higher number.
My guess is that the run loop isn't cycling. There's actually nothing in the run loop, and I'm not sure where to put one. In the ViewDidLoad delegate, I set up an update rate for the accelerometer, and call a function that updates the sublayers in the view. Everything else is event driven, so I don't know what I'd do with a run loop.
I've tried creating CALayers, and adding them as sublayers. I've also tried making the GraphViewSegment class a UIView, so it has it's own layer.
The version that's written in Objective C works perfectly reliably.
The way that this application works, is that acceleration values show up on the left side of the screen, and scroll to the right. To make it efficient, new acceleration values are written into a small sublayer that holds a graph for 32 time values. When it's full, that whole sublayer is just moved a pixel at a time to the right, and a new (or recycled) segment takes its place at the left side of the screen.
Here's the code that moves unchanged segments to the right by a pixel:
for s: GraphViewSegment in self.segments {
var position = s.layer.position
position.x += 1.0;
s.layer.position = position;
//s.layer.hidden = false
s.layer.setNeedsDisplay()
}
I don't think that the setNeedsDisplay is strictly necessary here, since it's called for the layer when the segment at the left gets a new line segment.
Here's how new layers are added:
public func addSegment() -> GraphViewSegment {
// Create a new segment and add it to the segments array.
var segment = GraphViewSegment(coder: self.coder)
// We add it at the front of the array because -recycleSegment expects the oldest segment
// to be at the end of the array. As long as we always insert the youngest segment at the front
// this will be true.
self.segments.insert(segment, atIndex: 0)
// this is now a weak reference
// Ensure that newly added segment layers are placed after the text view's layer so that the text view
// always renders above the segment layer.
self.layer.insertSublayer(segment.layer, below: self.text.layer)
// Position it properly (see the comment for kSegmentInitialPosition)
segment.layer.position = kSegmentInitialPosition;
//println("New segment added")
self.layer.setNeedsDisplay()
segment.layer.setNeedsDisplay()
return segment;
}
At this point I'm pretty confused. I've tried calling setNeedsDisplay all over the place, including the owning UIView. I've tried making the sublayers UIViews, and I've tried making them not be UIViews. No matter what I do, the behavior is always the same.
Everything is set up in viewDidLoad:
override func viewDidLoad() {
super.viewDidLoad()
pause.possibleTitles?.setByAddingObjectsFromArray([kLocalizedPause, kLocalizedResume])
isPaused = false
useAdaptive = false
self.changeFilter(LowpassFilter)
var accelerometerQueue = NSOperationQueue()
motionManager.accelerometerUpdateInterval = 1.0 / kUpdateFrequency
motionManager.startAccelerometerUpdatesToQueue(accelerometerQueue,
withHandler:
{(accelerometerData: CMAccelerometerData!, error: NSError!) -> Void in
self.accelerometer(accelerometerData)})
unfiltered.isAccessibilityElement = true
unfiltered.accessibilityLabel = "unfiltered graph"
filtered.isAccessibilityElement = true
filtered.accessibilityLabel = "filtered graph"
}
func accelerometer (accelerometerData: CMAccelerometerData!) {
if (!isPaused) {
let acceleration: CMAcceleration = accelerometerData.acceleration
filter.addAcceleration(acceleration)
unfiltered!.addPoint(acceleration.x, y: acceleration.y, z: acceleration.z)
filtered!.addPoint(filter.x, y: filter.y, z: filter.z)
//unfiltered.setNeedsDisplay()
}
}
Any idea?
I quite like Swift as a language - it takes the best parts of Java and C#, and adds some nice syntactic sugar. But this is driving me spare! I'm sure it's some little thing that I've overlooked, but I can't figure out what.
Since you've created a new NSOperationQueue for your accelerometer updates handler, everything that handler calls is also running in a separate queue, sequestered from the main run loop. I'd suggest either running that handler on the main thread NSOperationQueue.mainQueue() or moving anything that could update the UI back to the main thread via a block on the main queue:
NSOperationQueue.mainQueue().addOperationWithBlock {
// do UI stuff here
}