Hi, developers, I maintain a shipped app that uses string concatenation to construct Metal shader and compile on-device. Beta 4 seems disabled __asm keyword, resulting the compilation failure. The error is: v2/GEMMKernel.cpp:229: error: program_source:23:9: error: illegal string literal in 'asm' __asm("air.simdgroup_async_copy_1d.p3i8.p1i8"); The relevant code is available at https://github.com/liuliu/ccv/blob/unstable/lib/nnc/mfa/v2/GEMMHeaders.cpp#L30 although any __asm will trip this. Please give us guidance on whether this is a regression or this will be something enforced in 26 release. Personally, I would consider this as a bug given it won't impact anything "compiled" shaders. Thanks for your patience reading this!

Can I use them in SK and do the animations work? Thanks, Patrick

Hello, we are working on a iOS game project, as progress, the project grows larger and larger. Because we are using other game dependencies and libraries, here larger and larger refers to the whole project, and our source files integrated and compiled by Xcode are not many. Now, it seems we hit a bottleneck, when I add new files or functions to the previous files to implement a new feature, Xcode compile stucks(stops), it's Indexing | Initializing datastore forever, cannot produce a final build. macOS 15.1, Xcode 16.2 Can you provide any solutions to solve this problem? Also submitted Feedback ID #FB18432749

In my project I need to do the following: In runtime create metal Dynamic library from source. In runtime create metal Executable library from source and Link it with my previous created Dynamic library. Create compute pipeline using those two libraries created above. But I get the following error at the third step: Error Domain=AGXMetalG15X_M1 Code=2 "Undefined symbols: _Z5noisev, referenced from: OnTheFlyKernel " UserInfo={NSLocalizedDescription=Undefined symbols: _Z5noisev, referenced from: OnTheFlyKernel } import Foundation import Metal class MetalShaderCompiler { let device = MTLCreateSystemDefaultDevice()! var pipeline: MTLComputePipelineState! func compileDylib() -> MTLDynamicLibrary { let source = """ #include <metal_stdlib> using namespace metal; half3 noise() { return half3(1, 0, 1); } """ let option = MTLCompileOptions() option.libraryType = .dynamic option.installName = "@executable_path/libFoundation.metallib" let library = try! device.makeLibrary(source: source, options: option) let dylib = try! device.makeDynamicLibrary(library: library) return dylib } func compileExlib(dylib: MTLDynamicLibrary) -> MTLLibrary { let source = """ #include <metal_stdlib> using namespace metal; extern half3 noise(); kernel void OnTheFlyKernel(texture2d<half, access::read> src [[texture(0)]], texture2d<half, access::write> dst [[texture(1)]], ushort2 gid [[thread_position_in_grid]]) { half4 rgba = src.read(gid); rgba.rgb += noise(); dst.write(rgba, gid); } """ let option = MTLCompileOptions() option.libraryType = .executable option.libraries = [dylib] let library = try! self.device.makeLibrary(source: source, options: option) return library } func runtime() { let dylib = self.compileDylib() let exlib = self.compileExlib(dylib: dylib) let pipelineDescriptor = MTLComputePipelineDescriptor() pipelineDescriptor.computeFunction = exlib.makeFunction(name: "OnTheFlyKernel") pipelineDescriptor.preloadedLibraries = [dylib] pipeline = try! device.makeComputePipelineState(descriptor: pipelineDescriptor, options: .bindingInfo, reflection: nil) } }

Hi all I have two mystic issues with saving and fetching data to and from iCloud. Both repro only after first launch of an app. 1. [GKLocalPlayer fetchSavedGamesWithCompletionHandler:] After first attempt I can see 0 saved games (but i know that there is at least one saved game) and there is no any error. In case if I try fetch one more time (without any additional actions) even immediately after first attempt I receive saved games correctly (not 0) 2. [GKLocalPlayer saveGameData: withName: completionHandler:] After first attempt I can see error The requested operation could not be completed because local player has not been authenticated. In case if I try save one more time (without any additional actions) even immediately after first attempt I can save data successfully without any error I found the same issue in StackOverflow, but there are no fixes...

I am an AR developer working on Apple Silicon Macs. Currently, Reality Composer Pro does not allow exporting .reality files, and Reality Composer (classic) is not available for Apple Silicon. This creates a gap in the workflow for ARKit/RealityKit developers who need interactive .reality files for use in Xcode projects. Having the ability to export .reality files directly from Reality Composer Pro on Mac would greatly streamline development and enable a fully native workflow on modern Macs. Alternatively, bringing Reality Composer (classic) to Apple Silicon would also resolve this issue. I have submitted this as a feature request via Feedback Assistant (FB17900386). I encourage others with similar needs to reply or submit feedback as well. Thank you!

We have a released game in the App Store with Game Center Challenges. The challenges were working well in testing of the final version before the Game Center challenges went live. After release the activity that should take the player to the challenge in game results in this printout and we do not get informed by GKGameActivityListener of the activity happening in our code as we did before the Game Center challenges went live. “Invalid game activity definition. Failed to kick activity notification to GameKit. Error: Error Domain=GKErrorDomain Code=17 "(null)"” Also, Game Center reports that the are no challenges in GKChallengeDefinition.all even though there are ongoing challenges. The leaderboard results do get reported to Game Center though and show up as challenge entries in the Games app. At the moment we are trying to figure out if this is a problem on our end or a Game Center server issue.

I would love to use Background GPU Access to do some video processing in the background. However the documentation of BGContinuedProcessingTaskRequest.Resources.gpu clearly states: Not all devices support background GPU use. For more information, see Performing long-running tasks on iOS and iPadOS. Is there a list available of currently released devices that do (or don't) support GPU background usage? That would help to understand what part of our user base can use this feature. (And what hardware we need to test this on as developers.) For example it seems that it isn't supported on an iPad Pro M1 with the current iOS 26 beta. The simulators also seem to not support the background GPU resource. So would be great to understand what hardware is capable of using this feature!

Hello, I've been trying to leverage instanced rendering in RealityKit on visionOS but have not had success. RealityKit states this is supported: https://developer.apple.com/documentation/realitykit/validating-usd-files https://developer.apple.com/videos/play/wwdc2021/10075/?time=1373 https://developer.apple.com/videos/play/wwdc2023/10099/?time=772 RealityKit Trace metrics Validating instancing is working: To test I made a base visionOS app with immersive space and the entity replaced with my test usdz file. I've been using the RealityKit Trace profiling template in xcode instruments in the immersive space and volume closed. This gets consistent draw call results. If I have a single sphere mesh with one material I get one draw call, but the number of draw calls grows linearly with mesh count no matter how my entity is configured. What I've tried Create a test scene in blender, export with instancing enabled Create a test scene in Reality Composer Pro using references Author usda files by hand based on the OpenUSD spec Programatically create a MeshResource with Contents at runtime References https://openusd.org/release/api/_usd__page__scenegraph_instancing.html https://developer.apple.com/documentation/realitykit/meshresource https://developer.apple.com/documentation/realitykit/meshresource/instance Thank you

Hello, I recently watched the WWDC2025 session titled “Combine Metal 4 machine learning and graphics” (https://developer.apple.com/videos/play/wwdc2025/262/ ), and I’m very excited about the new Metal 4 features that integrate machine learning with graphics—such as neural ambient occlusion, shader-based ML inference, and the use of MTLTensor and MTL4MachineLearningCommandEncoder. While the session includes helpful code snippets and a compelling debug demo (e.g., the neural ambient occlusion example), the implementation details are not fully shown, and I haven’t been able to find a complete, runnable sample project that demonstrates end-to-end integration of ML and rendering in Metal 4. Would Apple be able to provide a full, working example—such as an Xcode project—that shows how to: Export a model to an .mlpackage, Convert it to an .mtlpackage, Use MTL4MachineLearningCommandEncoder alongside render passes, Or embed small neural networks directly in shaders using Shader ML? Having such a sample would greatly help developers like me adopt these powerful new capabilities correctly and efficiently. Thank you very much for your time and support! Best regards,

Hello everyone, I must have missed something but why isn't there a depthAttachmentPixelFormat to the new Metal 4 MTL4RenderPipelineDescriptor, unlike the old MTLRenderPipelineDescriptor? So how do you set the depth pixel format? Thanks in advance!

I am trying to learn Metal development on my MacBook Pro M1 Pro (Sequoia 15.3.1) on Xcode Playground, but when I write these two lines of code: import Metal let device = MTLCreateSystemDefaultDevice()! I get the error The LLDB RPC server has crashed. Any ideas as to what I can do to solve this? I have rebooted the machine and reinstalled Xcode...

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]) -&gt; 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! 🚀

I'm developing a game that supports GameKit turn based matches. What I don't understand is this: Is tapping on the Game Center notification push messages the only way for the GKTurnBasedEventListener to trigger? What if someone misses the push message (swiping it away by accident or something like that) but still wants to join? Is there some inbox somewhere where the pending messages can be seen or fetched? Also it was mentioned in a very old WWDC video (from 2013, I think that's the latest with information about turn based matches) that the notification also includes a badge for the icon. However, I do not understand how to implement that. Is there any documentation for that?

Hi team, I'm looking for the RealityKit debugger in Xcode 26 beta 3. I'm running a RealityKit app on my iPad running iPadOS 26 b3, but the debugger option is not there in Xcode.

I'm developing a turn based game. When I present the GKTurnBasedMatchmakerViewController players can opt in for automatch instead of selecting a specific friend as opponent. How exactly does the matching work if a player doesn't specify anything explicitly? Does Game Center send push notifications in a round robin fashion to all friends and the first one to accept is then matched as opponent? Is this documented somewhere?

I haven't been looking at screensavers for a long time because of Apple's lack of will (or resources?) to provide a public version of the private modern SDK used by Apple for a very long time now. I'm now looking at the Screen Saver pane in System Settings (the What-If version of System Preferences in an alternate universe where all screens are in portrait mode). In macOS Sequoia, it seems like 3rd party screensavers are not welcome considering that they are relegated to the "Other" section at the bottom of the list and you have to click Show All to start seeing 3rd party screen savers. I also had a quick look at macOS Tahoe Beta 3 and it looks like that all the real screensavers are gone (3rd party and the ones from Apple: Hello, Message, Flurry, etc.) or at least it requires to be a Nobel Prize to find them (and the Search field is not useful). I tried to install a 3rd party screen saver on macOS Tahoe Beta 3, it doesn't show up in the list. To summarize: No public access to modern APIs AFAIK. UI that is hostile to 3rd party screen savers on macOS Sequoia. Apparently only screensavers that are slideshows or movies curated by Apple in macOS Tahoe b3. Hence the question: Is there any future for screen savers on macOS? Because if there's none, I won't waste my time trying to update some old screen savers.

For an app of mine I use CGSetDisplayTransferByTable to adjust the gamma table of the device. Since macOS Tahoe, these modifications are silently ignored. The display's actual gamma curve remains unchanged despite the API reporting successful completion. I've filed a FB for it a few weeks ago, and would love to figure out what could be causing this. FB18559786

I'm experiencing an issue with PDFKit where page.removeAnnotation(annotation) successfully removes the annotation from the page's data structure, but the PDFView no longer updates automatically to reflect the change visually. Issue Details: The annotation is removed (verified by checking page.annotations.count) The PDFView display doesn't refresh to show the removal This code was working correctly before and suddenly stopped working No code changes were made on my end

Hi Apple team, Game Mode was introduced in iOS 18. To activate Game Mode, an app must include specific key-value pairs in its *.plist and be categorized as a "Game" on the App Store. My app (https://apps.apple.com/us/app/voidlink/id6747717070) works primarily as a self-hosted game streaming (PC->iPhone/iPad) client. Game Mode provides clear benefits in terms of latency and frame rate stability, but it can currently only be activated when running via Xcode or TestFlight. I am an individual iOS developer based in China, where an additional government license is required for apps to be listed under the "Game" category on the App Store. Obtaining such a license is very difficult for independent developers, so my app has been categorized under "Utilities" instead.(If move the app to game category, it will disappear from Chinese App Store immediately) Expectation / Suggestion: Please consider making Game Mode available as a local, user-controllable option on iOS18/26+, such as through a system “App Pool” where users can choose which apps to enable Game Mode for, regardless of App Store category. This would greatly benefit use cases like streaming clients, benchmarking tools, and remote play utilities, without requiring developers to reclassify their apps as “Games” on App Store.