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GKAccessPoint triggerAccessPointWithState handler not invoked on iOS 26.0 and iOS 15.8.4
GKAccessPoint triggerAccessPointWithState handler not invoked on iOS 26.0 and iOS 15.8.4 Incorrect/Unexpected Behaviour: When calling [GKAccessPoint.shared triggerAccessPointWithState:GKGameCenterViewControllerStateAchievements handler:^{}] on a real device running iOS 26 beta (iOS 26), the overlay appears as expected, but the handler block is never called. This behavior also not working correctly on previous iOS versions(tested on iOS 15.8.4) Steps to Reproduce: Authenticate GKLocalPlayer Call triggerAccessPointWithState:handler: with a block that logs or performs logic Observe that overlay appears, but block is not executed Behavior: UI appears correctly Handler is not invoked at all Expected Result: The handler should fire immediately after the dashboard is shown. Actual Result: The handler is never called. Usecase: As GKGameCenterViewController is deprecated we are moving to GKAccesspoint but due to above functionality issue we are unable to. Environment: Device: iPhone 16, iPhone 7 iOS: 26.0 and iOS 15.8.4 Xcode: 26.0 beta and Xcode 16.4
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Oct ’25
Metal 4 & Acceleration Structures
I have really enjoyed looking through the code and videos related to Metal 4. Currently, my interest is to update a ReSTIR Project and take advantage of more robust ways to refit acceleration Structures and more powerful ways to access resources. I am working in Swift and have encountered a couple of puzzles: What is the 'accepted' way to create a MTL4BufferRange to store indices and vertices? How do I properly rewrite Swift code to build and compact an Acceleration Structure? I do realize that this is all in Beta and will happily look through Code Samples this Fall. If other guidance is available earlier, that would be fabulous! Thank you
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667
Sep ’25
CustomMetalView sample uses deprecated functions - update?
The sample code here, has code like: // Create a display link capable of being used with all active displays cvReturn = CVDisplayLinkCreateWithActiveCGDisplays(&_displayLink); But that function's doc says it's deprecated and to use NSView/NSWindow/NSScreen displayLink instead. That returns CADisplayLink, not CVDisplayLink. Also the documentation for that displayLink method is completely empty. I'm not sure if I'm supposed to add it to run loop, or what, after I get it. It would be nice to get an updated version of this sample project and/or have some documentation in NSView.displayLink
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374
Jul ’25
How to play Vorbis/OGG files with swift?
Does anyone have a working example on how to play OGG files with swift? I've been trying for over a year now. I was able to wrap the C Vorbis library in swift. I then used it to parse an OGG file successfully. Then I was required to use Obj-C\++ to fill the PCM because this method seems to only be available in C\++ and that part hangs my app for a good 40 seconds to several minutes depending on the audio file, it then plays for about 2 seconds and then crashes. I can't get the examples on the Vorbis site to work in objective-c and i tried every example on github I could find (most of which are for iOS - I want to play the files on mac) I also tried using Cricket Audio framework below. https://github.com/sjmerel/ck It has a swift example and it can play their proprietary soundbank format but it is also supposed to play OGG and it just doesn't do anything when trying to play OGG as you can see in the posted issue https://github.com/sjmerel/ck/issues/3 Right now I believe every player that can play OGGs on mac is written in Objective-C or C++. Anyway, any help/advice is appreciated. OGG format is very prevalent in the gaming community. I could use unity, which I believe plays oggs through the mono framework but I really really want to stay in swift.
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4.4k
Jul ’25
Combining render encoders
When I take a frame capture of my application in Xcode, it shows a warning that reads "Your application created separate command encoders which can be combined into a single encoder. By combining these encoders you may reduce your application's load/store bandwidth usage." In the minimal reproduction case I've identified for this warning, I have two render pipeline states: The first writes to the current drawable, the depth buffer, and a secondary color buffer. The second writes only to the current drawable. Because these are writing to a different set of outputs, I was initially creating two separate render command encoders to handle the draws under each of these states. My understanding is that Xcode is telling me I could only create one, however when I try to do that, I get runtime asserts when attempting to apply the second render pipeline state since it doesn't have a matching attachment configured for the second color buffer or for the depth buffer, so I can't just combine the encoders. Is the only solution here to detect and propagate forward the color/depth attachments from the first state into the creation of the second state? Is there any way to suppress this specific warning in Xcode?
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310
Jul ’25
How to implement c for vision ?
I want to use reality to create a custom material that can use my own shader and support Mesh instancing (for rendering 3D Gaussian splating), but I found that CustomMaterial does not support VisionOS. Is there any other interface that can achieve my needs? Where can I find examples?
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102
Jul ’25
JPEG2000 (JP2) Decoding Works on iOS 16 but Fails on iOS 18
I am extracting a JPEG2000 (JP2) facial image from an NFC passport chip (ISO/IEC 19794-5) and attempting to create a UIImage from it. On iOS 16, the following code works fine: import ImageIO import UIKit func getUIImage(from imageData: [UInt8]) -> UIImage? { let data = Data(imageData) guard let imageSource = CGImageSourceCreateWithData(data as CFData, nil), let cgImage = CGImageSourceCreateImageAtIndex(imageSource, 0, nil) else { print("Failed to decode JP2 image!") return nil } return UIImage(cgImage: cgImage) } However, on iOS 18, this fails with errors like: initialize:1415: *** invalid JPEG2000 file *** makeImagePlus:3752: *** ERROR: 'JP2 ' - failed to create image [-50] CGImageSourceCreateImageAtIndex: *** ERROR: failed to create image [-59] Questions: Did Apple remove or modify JPEG2000 support in iOS 18? Is there an official workaround for decoding JPEG2000 on iOS 18? Should I use Vision/Metal/Core Image instead? Is there a recommended way to convert JPEG2000 to JPEG/PNG before creating a UIImage? Are there any Apple-provided APIs that maintain backward compatibility for JPEG2000 decoding? Additional Info: The UInt8 array has a valid JPEG2000 header (0x00 0x00 0x00 0x0C 6A 50 ...). The image works on iOS 16 but fails on iOS 18. Tested on iPhone running iOS 18.0 beta. Any insights on how to handle JPEG2000 decoding in iOS 18 would be greatly appreciated! 🚀
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Mar ’25
Unknown CHHapticError.Code (1852797029 == 'nope') in iOS 18+ on iPhone 11 Pro
Hello, I'm getting this error when launching a SpriteKit Swift game in iOS 18+ on an iPhone 11 Pro, whose shell is partly damaged in the back: CHHapticEngine.mm:1206 -[CHHapticEngine doStartWithCompletionHandler:]_block_invoke: ERROR: Player start failed: The operation couldn’t be completed. (com.apple.CoreHaptics error 1852797029.) Haptics do not work on this device, due to the damaged shell, so some error — which obviously occurs when calling start(completionHandler:) — is definitely expected; what is not expected is the main thread sometimes blocking for up to 5 seconds — although the method is not called from the main thread... the error itself is always displayed from some other secondary (system) thread. During this time, the main thread does not access the haptics engine at all; on average, it blocks once every four or five launches. In each launch (blocking or not), the 'nope' error is displayed ~5 seconds after trying to start the engine. After going nuts with all kinds of breakpoints and instrumentation, I'm at a loss as to why the main thread would sometimes block... Ideas, anyone? Thank you, D.
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Jul ’25
Bug Report - Incorrect trackingAreaIdentifier in visionOS 26 Hover Effect Sample Code
Description: In the official visionOS 26 Hover Effect sample code project , I encountered an issue where the event.trackingAreaIdentifier returned by onSpatialEvent does not reset as expected. Steps to Reproduce: Select an object with trackingAreaID = 6 in the sample app. Look at a blank space (outside any tracking area) and perform a pinch gesture . Expected Behavior: The event.trackingAreaIdentifier should return 0 when interacting with a non-tracking area. Actual Behavior: The event.trackingAreaIdentifier still returns 6, even after restarting the app or killing the process. This persists regardless of where the pinch gesture is performed
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289
Jul ’25
GameKit Configuration File - Apple Documentation out of Date
This is the first time I have tried adding achievements to my games. The online documentation says: "Before you can access achievements in your code, you can configure them in Xcode and sync the configuration updates you make with App Store Connect. Begin configuring achievements by creating a GameKit configuration file. In Xcode, choose File > New > File from Template. Select GameKit File, and click Next. In the sheet that appears, enter a name for the configuration and click Create." Sounds easy - except Xcode 16.2 does not have a GameKit File as one of the Templates. Please advise on how to proceed and it would be nice if the documentation were updated.
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149
May ’25
WWDC25 Metal & game technologies group lab
Hello, Thank you for attending today’s Metal & game technologies group lab at WWDC25! We were delighted to answer many questions from developers and energized by the community engagement. We hope you enjoyed it and welcome your feedback. We invite you to carry on the conversation here, particularly if your question appeared in Slido and we were unable to answer it during the lab. If your question received feedback let us know if you need clarification. You may want to ask your question again in a different lab e.g. visionOS tomorrow. (We realize that this can be confusing when frameworks interoperate) We have a lot to learn from each other so let’s get to Q&A and make the best of WWDC25! 😃 Looking forward to your questions posted in new threads.
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439
Jul ’25
How to Enable Game Mode
What is Game Mode? Game Mode optimizes your gaming experience by giving your game the highest priority access to your CPU and GPU, lowering usage for background tasks. And it doubles the Bluetooth sampling rate, which reduces input latency and audio latency for wireless accessories like game controllers and AirPods. See Use Game Mode on Mac See Port advanced games to Apple platforms How can I enable Game Mode in my game? Add the Supports Game Mode property (GCSupportsGameMode) to your game’s Info.plist and set to true Correctly identify your game’s Application Category with LSApplicationCategoryType (also Info.plist) Note: Enabling Game Mode makes your game eligible but is not a guarantee; the OS decides if it is ok to enable Game Mode at runtime An app that enables Game Mode but isn’t a game will be rejected by App Review. How can I disable Game Mode? Set GCSupportsGameMode to false. Note: On Mac Game Mode is automatically disabled if the game isn’t running full screen.
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533
Jul ’25
Testing Achievements - Apple Documentation out of Date
New to achievements. I added them in App Store Connect and want to test them. Apple Documentation says this: "Before you begin testing your GameKit configuration, you need to enable Debug Mode. In Xcode, choose Product > Scheme > Edit Scheme. From the Run configuration, select Options and toggle Enable Debug Mode. To begin testing your achievement configuration, open the game Progress Manager. In Xcode, choose Debug > GameKit > Manage Game Progress." Sounds easy enough, but there is no "GameKit" under Debug in Xcode 16.2.
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150
May ’25
CAMetalLayer nextDrawable crash
Hi , My application meet below crash backtrace at very low repro rate from the public users, i do not see it relate to a specific iOS version or iPhone model. The last code line from my application is calling CAMetalLayer nextDrawable API. I did some basic studying, suppose it may relate to the wrong CAMetaLayer configuration, like frame property w or h <= 0.0 bounds property w or h <= 0.0 drawableSize w or h <= 0.0 or w or h > max value (like 16384) Not sure my above thinking is right or not? Will the UIView which my CAMetaLayer attached will cause such nextDrawable crash or not ? Thanks a lot Main Thread - Crashed libsystem_kernel.dylib __pthread_kill libsystem_c.dylib abort libsystem_c.dylib __assert_rtn Metal MTLReportFailure.cold.1 Metal MTLReportFailure Metal _MTLMessageContextEnd Metal -[MTLTextureDescriptorInternal validateWithDevice:] AGXMetalA13 0x245b1a000 + 4522096 QuartzCore allocate_drawable_texture(id<MTLDevice>, __IOSurface*, unsigned int, unsigned int, MTLPixelFormat, unsigned long long, CAMetalLayerRotation, bool, NSString*, unsigned long) QuartzCore get_unused_drawable(_CAMetalLayerPrivate*, CAMetalLayerRotation, bool, bool) QuartzCore CAMetalLayerPrivateNextDrawableLocked(CAMetalLayer*, CAMetalDrawable**, unsigned long*) QuartzCore -[CAMetalLayer nextDrawable] SpaceApp -[MetalRender renderFrame:] MetalRenderer.mm:167 SpaceApp -[FrameBuffer acceptFrame:] VideoRender.mm:173 QuartzCore CA::Display::DisplayLinkItem::dispatch_(CA::SignPost::Interval<(CA::SignPost::CAEventCode)835322056>&) QuartzCore CA::Display::DisplayLink::dispatch_items(unsigned long long, unsigned long long, unsigned long long) QuartzCore CA::Display::DisplayLink::dispatch_deferred_display_links(unsigned int) UIKitCore _UIUpdateSequenceRun UIKitCore schedulerStepScheduledMainSection UIKitCore runloopSourceCallback CoreFoundation __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ CoreFoundation __CFRunLoopDoSource0 CoreFoundation __CFRunLoopDoSources0 CoreFoundation __CFRunLoopRun CoreFoundation CFRunLoopRunSpecific GraphicsServices GSEventRunModal UIKitCore -[UIApplication _run] UIKitCore UIApplicationMain
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371
Jul ’25
Problem running Unreal 5.6
I am using Unreal Engine 5.6 on a MacBook Pro with an M3 chip and macOS 15.5. I’ve installed Xcode and accepted the license, but Unreal is not detecting the latest Metal Shader Standard (Metal v3.0). The maximum version Unreal sees is Metal v2.4, even though the hardware and OS should support Metal 3.0. I’ve also run sudo xcode-select -s /Applications/Xcode.app and accepted the license via Terminal. Is there anything in Xcode settings, SDK availability, or system permissions that could be preventing access to Metal 3.0 features?"
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501
Jul ’25
RealityKit and Reality Composer Pro aren't forward or backward compatible with each other
TL;DR: RealityKit and Reality Composer Pro aren't forward or backward compatible with each other, and the resulting error message is terse and unhelpful. (FB14828873) So far, I've been sticking with Xcode 16.4 for development and only using Xcode 26.0 beta experimentally. Yesterday, I used xcode-select to switch to Xcode 26.0 beta 3 to test it, but I forgot to switch back. Consequently, this morning I unintentionally used the future Reality Composer Pro (the version included with Xcode 26) to make a small change to a USD file. Now I realize that if I'm unlucky, it's possible Reality Composer Pro may have silently introduced a small change into the USD file that may make RealityKit fail to read the file on iOS 18 and visionOS 2, which in the past has resulted in hours of debugging to track down the source of the failure, often a single line in the USD file that RealityKit can't communicate to me other than with the error "the operation couldn't be completed". As an analogy, this situation is as if, during regular development (not involving Reality Composer Pro), Xcode didn't warn you about specific API version conflicts, but instead failed with a generic error message, without highlighting the line in your Swift file that was the source of the error.
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473
Jul ’25
How to Configure angularLimitInYZ for PhysicsSphericalJoint in RealityKit (Pendulum/Swing Behavior)
Hello RealityKit developers, I'm currently working on physics simulations in my visionOS app and am trying to adapt the concepts from the official sample Simulating physics joints in your RealityKit app. In the sample, a sphere is connected to the ceiling using a PhysicsRevoluteJoint to create a hinge-like simulation. I've successfully modified this setup to use a PhysicsSphericalJoint instead. The basic replacement works as expected: pin1 (attached to the sphere) rotates freely around pin0 (attached to the ceiling), much like a ball-and-socket joint should, removing all translational degrees of freedom. My challenge lies with the PhysicsSphericalJoint's angularLimitInYZ property. The documentation mentions that this property allows limiting the rotation around the Y and Z axes, defining an "elliptical cone shape around the x-axis of pin0." However, I'm struggling to understand how to specify these values to achieve a desired rotational limit. If I have a sphere that is currently capable of rotating 360 degrees around pin0 (like a free-spinning ball on a string), how would I use angularLimitInYZ to restrict its rotation to a certain height or angular range, preventing it from completing a full circle? Specifically, I'm trying to achieve a "swing" like behavior where the sphere oscillates back and forth but cannot rotate completely overhead or underfoot. What values or approach should I use for the angularLimitInYZ tuple to define such a restricted pendulum-like motion? Any insights, code examples, or explanations on how to properly configure angularLimitInYZ for this kind of behavior would be incredibly helpful! The following code is modified from the sample. extension MainView { func addPinsTo(ballEntity: Entity, attachmentEntity: Entity) throws { let hingeOrientation = simd_quatf(from: [1, 0, 0], to: [0, 0, 1]) let attachmentPin = attachmentEntity.pins.set( named: "attachment_hinge", position: .zero, orientation: hingeOrientation ) let relativeJointLocation = attachmentEntity.position( relativeTo: ballEntity ) let ballPin = ballEntity.pins.set( named: "ball_hinge", position: relativeJointLocation, orientation: hingeOrientation ) // Create a PhysicsSphericalJoint between the two pins. let revoluteJoint = PhysicsSphericalJoint(pin0: attachmentPin, pin1: ballPin) try revoluteJoint.addToSimulation() } } The following image is a screenshot of the operation when changing to PhysicsSphericalJoint. Thank you in advance for your assistance.
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275
Jul ’25
How to obtain frame rate for iOS proMotion devices
Due to the release of ProMotion devices, the system may switch frame rates in certain scenarios, resulting in the loss of reference value for data collected through CADisplayLink callbacks at a fixed 60Hz frame rate. We cannot distinguish whether the slow callback of CADisplayLink is due to a stutter or a system switch in frame rate. I know Hitch Time Ratio, but I can't use this scheme for some reasons. How can I distinguish between stuck and frame rate gear shift in CADisplaylink callback? In iOS 15, CADisplayLink.preferredFrameRateRange.preferred always returns 0, while minimum and maximum do change. Can I use these minimum and maximum range values as criteria to distinguish between frame rate switching and stuttering?
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154
May ’25