ARKit SceneKit ARSCNView with Positional Audio SCNAudioPlayer WILL NOT STOP playing - audio

Running ARKit 2.0 with an ARSCNView. iOS12
The application uses multithreading, that's why these functions are being performed on the main thread (just to be sure). I also tried without explicitly performing the functions on the main thread too, with no avail.
I'm using an .aiff sound file but have also tried a .wav. No joy.
I even tried removing audioNode_alarm from the node hierarchy & the sound still plays. I even remove the ARSCNView from the view hierarchy and the sound STILL plays. FFS
From what I can see, I'm doing things EXACTLY as I'm supposed to, to stop the audio from playing. The audio simply will not stop no matter what I try. Can anyone think why?!
weak var audioNode_alarm: SCNNode!
weak var audioPlayer_alarm: SCNAudioPlayer?
func setupAudioNode() {
let audioNode_alarm = SCNNode()
addChildNode(audioNode_alarm)
self.audioNode_alarm = audioNode_alarm
}
func playAlarm() {
DispatchQueue.main.async { [unowned self] in
self.audioNode_alarm.removeAllAudioPlayers()
if let audioSource_alarm = SCNAudioSource(fileNamed: "PATH_TO_MY_ALARM_SOUND.aiff") {
audioSource_alarm.loops = true
audioSource_alarm.load()
audioSource_alarm.isPositional = true
let audioPlayer_alarm = SCNAudioPlayer(source: audioSource_alarm)
self.audioNode_alarm.addAudioPlayer(audioPlayer_alarm)
self.audioPlayer_alarm = audioPlayer_alarm
}
}
}
func stopAlarm() {
DispatchQueue.main.async { [unowned self] in
self.audioNode_alarm?.removeAudioPlayer(self.audioPlayer_alarm!)
self.audioNode_alarm?.removeAllAudioPlayers()
}
}

What I ended up doing is stopping the sound and removing the player by
yourNode.audioPlayers.forEach { audioLocalPlayer in
audioLocalPlayer.audioNode?.engine?.stop()
yourNode.removeAudioPlayer(audioLocalPlayer)
}
According to the documentation SCNAudioPlayer has audioNode, which is supposed to be used "to vary parameters such as volume and reverb in real time during playback".
audioNode is of AVAudioNode type, so if we jump to engine prop and its type definition, we'll find all the controls we need.

Related

Should the variable value be checked before assigning?

I know this might sound like a silly question but I'm curious should I check my variable value before assigning?
like for example if I'm flipping my skin (Node2D composed of sprite & raycast) based on direction (Vector2) :
func _process(delta):
...
if(direction.x>0):
skin.scale.x=1
elif(direction.x<0):
skin.scale.x=-1
#OR
if(direction.x>0):
if(skin.scale.x!=1):
skin.scale.x=1
elif(direction.x<0):
if(skin.scale.x!=-1):
skin.scale.x=-1
would the skin scale be altered every _process hence consuming more CPU usage
OR
if the value is same will it be ignored?
First of all, given that this is GDScript, so the number of lines will be a performance factor.
We will look at the C++ side…
But before that… Be aware that GDScript does some trickery with properties.
When you say skin.scale Godot will call get_scale on the skin object, which returns a Vector2. And Vector2 is a value type. That Vector2 is not the scale that the object has, but a copy, an snapshot of the value. So, in virtually any other language skin.scale.x=1 is modifying the Vector2 and would have no effect on the scale of the object. Meaning that you should do this:
skin.scale = Vector2(skin.scale.x + 1, skin.scale.y)
Or this:
var skin_scale = skin.scale
skin_scale.x += 1
skin.scale = skin_scale
Which I bet people using C# would find familiar.
But you don't need to do that in GDScript. Godot will call set_scale, which is what most people expect. It is a feature!
So, you set scale, and Godot will call set_scale:
void Node2D::set_scale(const Size2 &p_scale) {
if (_xform_dirty) {
((Node2D *)this)->_update_xform_values();
}
_scale = p_scale;
// Avoid having 0 scale values, can lead to errors in physics and rendering.
if (Math::is_zero_approx(_scale.x)) {
_scale.x = CMP_EPSILON;
}
if (Math::is_zero_approx(_scale.y)) {
_scale.y = CMP_EPSILON;
}
_update_transform();
_change_notify("scale");
}
The method _change_notify only does something in the editor. It is the Godot 3.x instrumentation for undo/redo et.al.
And set_scale will call _update_transform:
void Node2D::_update_transform() {
_mat.set_rotation_and_scale(angle, _scale);
_mat.elements[2] = pos;
VisualServer::get_singleton()->canvas_item_set_transform(get_canvas_item(), _mat);
if (!is_inside_tree()) {
return;
}
_notify_transform();
}
Which, as you can see, will update the Transform2D of the Node2D (_mat). Then it is off to the VisualServer.
And then to _notify_transform. Which is what propagates the change in the scene tree. It is also what calls notification(NOTIFICATION_LOCAL_TRANSFORM_CHANGED) if you have enabled it with set_notify_transform. It looks like this (this is from "canvas_item.h"):
_FORCE_INLINE_ void _notify_transform() {
if (!is_inside_tree()) {
return;
}
_notify_transform(this);
if (!block_transform_notify && notify_local_transform) {
notification(NOTIFICATION_LOCAL_TRANSFORM_CHANGED);
}
}
And you can see it delegates to another _notify_transform that looks like this (this is from "canvas_item.cpp"):
void CanvasItem::_notify_transform(CanvasItem *p_node) {
/* This check exists to avoid re-propagating the transform
* notification down the tree on dirty nodes. It provides
* optimization by avoiding redundancy (nodes are dirty, will get the
* notification anyway).
*/
if (/*p_node->xform_change.in_list() &&*/ p_node->global_invalid) {
return; //nothing to do
}
p_node->global_invalid = true;
if (p_node->notify_transform && !p_node->xform_change.in_list()) {
if (!p_node->block_transform_notify) {
if (p_node->is_inside_tree()) {
get_tree()->xform_change_list.add(&p_node->xform_change);
}
}
}
for (CanvasItem *ci : p_node->children_items) {
if (ci->top_level) {
continue;
}
_notify_transform(ci);
}
}
So, no. There is no check to ignore the change if the value is the same.
However, it is worth noting that Godot invalidates the global transform instead of computing it right away (global_invalid). This is does not make multiple updates to the transform in the same frame free, but it makes them cheaper than otherwise.
I also remind you that looking at the source code is no replacement for using a profiler.
Should you check? Perhaps… If there are many children that need to be updated the extra lines are likely cheap enough. If in doubt: measure with a profiler.

Coordinating emission and subscription in Kotlin coroutines with hot flows

I am trying to design an observable task-like entity which would have the following properties:
Reports its current state changes reactively
Shares state and result events: new subscribers will also be notified if the change happens after they've subscribed
Has a lifecycle (backed by CoroutineScope)
Doesn't have suspend functions in the interface (because it has a lifecycle)
The very basic code is something like this:
class Worker {
enum class State { Running, Idle }
private val state = MutableStateFlow(State.Idle)
private val results = MutableSharedFlow<String>()
private val scope = CoroutineScope(Dispatchers.Default)
private suspend fun doWork(): String {
println("doing work")
return "Result of the work"
}
fun start() {
scope.launch {
state.value = State.Running
results.emit(doWork())
state.value = State.Idle
}
}
fun state(): Flow<State> = state
fun results(): Flow<String> = results
}
The problems with this arise when I want to "start the work after I'm subscribed". There's no clear way to do that. The simplest thing doesn't work (understandably):
fun main() {
runBlocking {
val worker = Worker()
// subscriber 1
launch {
worker.results().collect { println("received result $it") }
}
worker.start()
// subscriber 2 can also be created "later" and watch
// for state()/result() changes
}
}
This prints only "doing work" and never prints a result. I understand why this happens (because collect and start are in separate coroutines, not synchronized in any way).
Adding a delay(300) to coroutine inside doWork "fixes" things, results are printed, but I'd like this to work without artificial delays.
Another "solution" is to create a SharedFlow from results() and use its onSubscription to call start(), but that didn't work either last time I've tried.
My questions are:
Can this be turned into something that works or is this design initially flawed?
If it is flawed, can I take some other approach which would still hit all the goals I have specified in the beginning of the post?
Your problem is that your SharedFlow has no buffer set up, so it is emitting results to its (initially zero) current collectors and immediately forgetting them. The MutableSharedFlow() function has a replay parameter you can use to determine how many previous results it should store and replay to new collectors. You will need to decide what replay amount to use based on your use case for this class. For simply displaying latest results in a UI, a common choice is a replay of 1.
Depending on your use case, you may want to give your CoroutineScope a SupervisorJob() in its context so it isn't destroyed by any child job failing.
Side note, your state() and results() functions should be properties by Kotlin convention, since they do nothing but return references. Personally, I would also have them return read-only StateFlow/SharedFlow instead of just Flow to clarify that they are not cold.

WatchOS and when to put methods on the main thread

It seems like for WatchOS extensions, it is more often the case where code needs to be explicitly placed on the main thread, as opposed to explicitly put in the background or another queue as in IOS. What activities need to be explicitly put on the main thread in WatchOS extensions? What I have seen is that this is being done when either updating the user interface or when changing the state of a workout with HealthKit.
For example, before I update the label values on my watchOS interface view controller I am calling the main queue:
func locationUpdate(locationDict: [String:AnyObject]) {
dispatch_async(dispatch_get_main_queue()) {
if let first = locationDict["firstValue"] as? String {
self.firstValue.setText(first)
}
if let second = locationDict["second"] as? String {
self.secondValue.setText(second)
}
}
Is this required? I would not do this in iOS. Are there other common cases? Is there a good reference regarding special main queue considerations for WatchOS?

passing around NSManagedObjects

I get strange errors when I am trying to pass around NSManagedObject through several functions. (all are in the same VC).
Here are the two functions in question:
func syncLocal(item:NSManagedObject,completionHandler:(NSManagedObject!,SyncResponse)->Void) {
let savedValues = item.dictionaryWithValuesForKeys([
"score",
"progress",
"player"])
doUpload(savedParams) { //do a POST request using params with Alamofire
(success) in
if success {
completionHandler(item,.Success)
} else {
completionHandler(item,.Failure)
}
}
}
func getSavedScores() {
do {
debugPrint("TRYING TO FETCH LOCAL SCORES")
try frc.performFetch()
if let results = frc.sections?[0].objects as? [NSManagedObject] {
if results.count > 0 {
print("TOTAL SCORE COUNT: \(results.count)")
let incomplete = results.filter({$0.valueForKey("success") as! Bool == false })
print("INCOMPLETE COUNT: \(incomplete.count)")
let complete = results.filter({$0.valueForKey("success") as! Bool == true })
print("COMPLETE COUNT: \(complete.count)")
if incomplete.count > 0 {
for pendingItem in incomplete {
self.syncScoring(pendingItem) {
(returnItem,response) in
let footest = returnItem.valueForKey("player") //only works if stripping syncScoring blank
switch response { //response is an enum
case .Success:
print("SUCCESS")
case .Duplicate:
print("DUPLICATE")
case .Failure:
print("FAIL")
}
}
} //sorry for this pyramid of doom
}
}
}
} catch {
print("ERROR FETCHING RESULTS")
}
}
What I am trying to achieve:
1. Look for locally saved scores that could not submitted to the server.
2. If there are unsubmitted scores, start the POST call to the server.
3. If POST gets 200:ok mark item.key "success" with value "true"
For some odd reason I can not access returnItem at all in the code editor - only if I completely delete any code in syncLocal so it looks like
func syncLocal(item:NSManagedObject,completionHandler:(NSManagedObject!,SyncResponse)->Void) {
completionHandler(item,.Success)
}
If I do that I can access .syntax properties in the returning block down in the for loop.
Weirdly if I paste the stuff back in, in syncLocal the completion block keeps being functional, the app compiles and it will be executed properly.
Is this some kind of strange XCode7 Bug? Intended NSManagedObject behaviour?
line 1 was written with stripped, line 2 pasted rest call back in
There is thread confinement in Core Data managed object contexts. That means that you can use a particular managed object and its context only in one and the same thread.
In your code, you seem to be using controller-wide variables, such as item. I am assuming the item is a NSManagedObject or subclass thereof, and that its context is just one single context you are using in your app. The FRC context must be the main thread context (a NSManagedObjectContext with concurrency type NSMainThreadConcurrencyType).
Obviously, the callback from the server request will be on a background thread. So you cannot use your managed objects.
You have two solutions. Either you create a child context, do the updates you need to do, save, and then save the main context. This is a bit more involved and you can look for numerous examples and tutorials out there to get started. This is the standard and most robust solution.
Alternatively, inside your background callback, you simply make sure the context updates occur on the main thread.
dispatch_async(dispatch_get_main_queue()) {
// update your managed objects & save
}

Can I use HaxeUI with HaxeFlixel?

I tried to use both HaxeUI and HaxeFlixel, but what I obtain is HaxeUI's interface over a white background, covering everything underneath. Moreover, even if it was possible to somewhat make HaxeUI and HaxeFlixel work together, it's not clear how to change the UI of HaxeUI when the state change in HaxeFlixel. Here is the code I used:
private function setupGame():Void {
Toolkit.theme = new GradientTheme();
Toolkit.init();
var stageWidth:Int = Lib.current.stage.stageWidth;
var stageHeight:Int = Lib.current.stage.stageHeight;
if (zoom == -1) {
var ratioX:Float = stageWidth / gameWidth;
var ratioY:Float = stageHeight / gameHeight;
zoom = Math.min(ratioX, ratioY);
gameWidth = Math.ceil(stageWidth / zoom);
gameHeight = Math.ceil(stageHeight / zoom);
}
trace('stage: ${stageWidth}x${stageHeight}, game: ${gameWidth}x${gameHeight}, zoom=$zoom');
addChild(new FlxGame(gameWidth, gameHeight, initialState, zoom, framerate, framerate, skipSplash, startFullscreen));
Toolkit.openFullscreen(function(root:Root) {
var view:IDisplayObject = Toolkit.processXmlResource("assets/xml/haxeui-resource.xml");
root.addChild(view);
});
}
I can guess that, probably, both HaxeUI and HaxeFlixel have their own main loop and that their event handling might not be compatible, but just in case, can someone have a more definitive answer?
Edit:
Actually, it's much better when using openPopup:
Toolkit.openPopup( { x:20, y:150, width:100, height:100 }, function(root:Root) {
var view:IDisplayObject = Toolkit.processXmlResource("assets/xml/haxeui-naming.xml");
root.addChild(view);
});
It's possible to interact with the rest of the screen (managed with HaxeFlixel), but the mouse pointer present in the part of the screen managed with HaxeFlixel remains under the HaxeUI user interface elements.
When using Flixel and HaxeUI together, its almost like running two applications at once. However, they both rely on OpenFL as a back-end and each attach themselves to its display tree.
One technique I'm experimenting with right now is to open a Flixel sub state, and within the sub state, call Toolkit.openFullscreen(). From inside of this, you can set the alpha of the root's background to 0, which allows you to see through it onto the underlying bitmap that Flixel uses to render.
Here is a minimal example of how you might "embed" an editor interface inside a Flixel sub state:
import haxe.ui.toolkit.core.Toolkit;
import haxe.ui.toolkit.core.RootManager;
import haxe.ui.toolkit.themes.DefaultTheme;
import flixel.FlxG;
import flixel.FlxSubState;
// This would typically be a Haxe UI XMLController
import app.MainEditor;
class HaxeUIState extends FlxSubState
{
override public function create()
{
super.create();
// Flixel uses a sprite-based cursor by default,
// so you need to enable the system cursor to be
// able to see what you're clicking.
FlxG.mouse.useSystemCursor = true;
Toolkit.theme = new DefaultTheme();
Toolkit.init();
Toolkit.openFullscreen(function (root) {
var editor = new MainEditor();
// Allows you to see what's going on in the sub state
root.style.backgroundAlpha = 0;
root.addChild(editor.view);
});
}
override public function destroy()
{
super.destroy();
// Switch back to Flixel's cursor
FlxG.mouse.useSystemCursor = true;
// Not sure if this is the "correct" way to close the UI,
// but it works for my purposes. Alternatively you could
// try opening the editor in advance, but hiding it
// until the sub-state opens.
RootManager.instance.destroyAllRoots();
}
// As far as I can tell, the update function continues to get
// called even while Haxe UI is open.
override public function update() {
super.update();
if (FlxG.keys.justPressed.ESCAPE) {
// This will implicitly trigger destroy().
close();
}
}
}
In this way, you can associate different Flixel states with different Haxe UI controllers. (NOTE: They don't strictly have to be sub-states, that's just what worked best in my case.)
When you open a fullscreen or popup with haxeui, the program flow will be blocked (your update() and draw() function won't be called). You should probably have a look at flixel-ui instead.
From my experience haxeflixel and haxeui work well together but they are totally independent projects, and as such, any coordination between flixel states and displayed UI must be added by the coder.
I don't recall having the white background problem you mention, it shouldn't happen unless haxeui root sprite has a solid background, in that case it should be addressed to haxeui project maintainer.

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