I just built Core and GameKit without errors. The command line I used was the following: python3 build.py -p Core GameKit -m macOS -c "Apple Development ID (redacted)" When importing these packages into Unity, as soon as the editor refreshes I get these errors: DllNotFoundException: GameKitWrapper assembly:<unknown assembly> type:<unknown type> member:(null) And DllNotFoundException: AppleCoreNativeMac assembly:<unknown assembly> type:<unknown type> member:(null) And Apple Unity Plug-ins] No Apple native plug-in libraries found. Were the libraries built with the build script (build.py), xcodebuild, or Xcode? Was any output generated from the build script/tool? Were there any errors or issues? Please check to ensure that libraries (.a, .framework, or .bundle files) were created and saved to each plug-in's "NativeLibraries~" folder. I made sure that the libraries were saved to this NativeLibraries folder. I made sure to update xcode, python, npm and Unity to the latest version, got the most recent commity from Github (Sept. 17th) but the errors persist. The errors also occur right as the game starts in a built player. Also occurs in a blank Unity project, where I tested both 2022.3.17f and 2022.3.48f. The versions I was trying to import was Core 3.1.4 and GameKit 3.0.0. Same issue with Core 3.1.3 and Gamekit 2.2.2. Last version I tried that works was Core 1.05 and GameKit 1.04. I haven't seen anyone else encounter this on these forums so I'm guessing that I'm personally doing something wrong rather than there being an issue with the plugins themselves, but what am I doing wrong?

Hello dear forum, I need to emit an exact amount of particles from a SCNParticleSystem in a burst (this is for an UI effect). This worked for me perfectly in the scene editor by setting the birthrate to the amount and emission duration to 0. Sadly when I either load such a particle system from a scene or creating it by code, the emitted particles are sometimes one less, or one more. The first time I run it in the simulator, it seems to work fine but then amount of particles varies as described. video: https://youtube.com/shorts/MRzqWBy2ypA?feature=share Does anybody know how to make this predictable? Thanks so much in advance, Seb

So I'm installing the toolkit but during the process the terminal just gives me this: Last 15 lines from /Users/quiqu/Library/Logs/Homebrew/game-porting-toolkit/01.configure: --enable-win64 --with-gnutls --with-freetype --with-gstreamer CC=/usr/local/opt/game-porting-toolkit-compiler/bin/clang CXX=/usr/local/opt/game-porting-toolkit-compiler/bin/clang++ checking build system type... x86_64-apple-darwin23.5.0 checking host system type... x86_64-apple-darwin23.5.0 checking whether make sets $(MAKE)... yes checking for gcc... /usr/local/opt/game-porting-toolkit-compiler/bin/clang checking whether the C compiler works... no configure: error: in /private/tmp/game-porting-toolkit-20240928-16869-7g5o5t/wine64-build': configure: error: C compiler cannot create executables See config.log' for more details If reporting this issue please do so to (not Homebrew/brew or Homebrew/homebrew-core): apple/apple quiqu@Quiques-Laptop ~ % please if someone could help I have a tournament this weekend and I need this to work

Hi folks, I'm working on a Tile based Deferred renderer, similar to this Apple example. I'm wondering how to add MSAA to the renderer, and I see two choices: Copy the single-sampled texture at the end of the GBuffer/Lighting render pass to a multi-sampled texture and resolve from that Make all render targets (GBuffer) multi-sampled and deal with sampling/resolving all intermediate textures as well as the final, combined texture. Which is the proper approach, and are there any examples of how to implement it? Thanks!

There is a sample project from Apple here. It has a scene of a city at night and you can move in it. It basically has 2 parts: application code written in what looks like Objective-C (I am more familiar with C++), which inherits from things like NSObject, MTKView, NSViewController and so on - it processes input and all app-related and window-related stuff. rendering code that also looks like Objective-C. Btw both parts are mostly in .mm files (Obj-C++ AFAIK). The application part directly uses only one class from the rendering part - AAPLRenderer. I want to move the rendering part to C++ using metal-cpp. For that I need to link metal-cpp to the project. I did it successfully with blank projects several times before using this tutorial. But with this sample project Xcode can't find Foundation/Foundation.hpp (and other metal-cpp headers). The error says this: Did not find header 'Foundation.hpp' in framework 'Foundation' (loaded from '/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX15.0.sdk/System/Library/Frameworks') Pls help

Hi I have setup animation using timeline in Reality Composer Pro like below This get triggered by a notification posts from the code.Once this time line triggered, I want to repeat this 2 animations in the timeline unitll user takes the next action. How can I make these repeat forever?

Hi, I am recently writing metal shader language to parallelize the algorithms to accelerate the speed of it. I created a simple example to show the acceleration result of it. Since Rust is used in our algorithm, so I used metal-rs as the wrapper to execute the MSL kernels from rust side. In this example, I am calculating the result of two arrays, and kernel looks like: kernel void two_array_addition_2( constant uint* a [[buffer(0)]], constant uint* b [[buffer(1)]], device uint* c [[buffer(2)]], uint idx [[thread_position_in_grid]] ) { c[idx] = a[idx] + b[idx]; } in the main.rs, you can see a function called execute_kernel() , this function has all it needs to execute the kernel in MSL (such as commandEncoder, piplelineState, etc). use core::mem; use metal::{Buffer, MTLSize}; use objc::rc::autoreleasepool; use std::time::Instant; use two_array_addition::abstractions::state::MetalState; fn execute_kernel( name: &str, state: &MetalState, input_a: &Buffer, input_b: &Buffer, output_c: &Buffer, ) -> Vec<u32> { // assert!(input_a.len() == input_b.len() && input_a.len() == output_c.len()); // let len = input_a.len() as u64; let len = input_a.length() as u64 / mem::size_of::<u32>() as u64; // 1. Init the MetalState // - we inited it // 2. Set up Pipeline State let pipeline = state.setup_pipeline(name).unwrap(); // 3. Allocate the buffers for A, B, and C // - we allocated outside of this function let mut result: &[u32] = &[]; autoreleasepool(|| { // 4. Create the command buffer & command encoder let (command_buffer, command_encoder) = state.setup_command( &pipeline, Some(&[(0, input_a), (1, input_b), (2, output_c)]), ); // 5. command encoder dispatch the threadgroup size and num of threads per threadgroup let threadgroup_count = MTLSize::new((len + 256 - 1) / 256, 1, 1); let thread_per_threadgroup = MTLSize::new(256, 1, 1); // let grid_size = MTLSize::new(len, 1, 1); // let threadgroup_count = MTLSize::new(pipeline.max_total_threads_per_threadgroup(), 1, 1); command_encoder.dispatch_thread_groups(threadgroup_count, thread_per_threadgroup); command_encoder.end_encoding(); command_buffer.commit(); command_buffer.wait_until_completed(); // 6. Copy the result back to the host let start = Instant::now(); result = MetalState::retrieve_contents::<u32>(output_c); let duration = start.elapsed(); println!("Duration for copying result back to host: {:?}", duration); }); result.to_vec() } The performance of the result is kinda interesting to me. This is the result: $ cargo run -r This is expected to run for a while... please wait... Generating input arrays... Generating input arrays... Generating output array... Generating expected output... Duration for allocating buffers: 2.015258s Executing 1st kernel (1)... Duration for copying result back to host: 5.75µs Executing 1st kernel (2)... Duration for copying result back to host: 542ns Executing 2nd kernel (1)... Duration for copying result back to host: 1µs Executing 2nd kernel (2)... Duration for copying result back to host: 458ns Duration expected: 183.406167ms Duration for 1st kernel (1): 1.894994875s Duration for 1st kernel (2): 537.318208ms Duration for 2nd kernel (1): 501.33275ms Duration for 2nd kernel (2): 497.339916ms You have successfully run the kernels! The speed is slower when executing in the MSL kernel, while I reckon of the dataset is quite big ($2^{29}$) The first kernel execution takes more time to launch. Is there any way to optimize the MSL in this case? And in most case, when you design the algorithm into parallelism, what would be the concerns? The machine I am using is M1 Pro with 14-core GPU and 16 GB memory. Does anyone have idea / explanation for why these happen? Thank you

I am unable to get VisionOS 2.0 (simulator) to receive the GCControllerDidConnect notification and thus am unable to setup support for a gamepad. However, it works in VisionOS 1.2. For VisionOS 2.0 I've tried adding: .handlesGameControllerEvents(matching: .gamepad) attribute to the view Supports Controller User Interaction to Info.plist Supported game controller types -> Extended Gamepad to Info.plist ...but the notification still doesn't fire. It does when the code is run from VisionOS 1.2 simulator, both of which have the Send Game Controller To Device option enabled. Here is the example code. It's based on the Xcode project template. The only files updated were ImmersiveView.swift and Info.plist, as detailed above: import SwiftUI import GameController import RealityKit import RealityKitContent struct ImmersiveView: View { var body: some View { RealityView { content in // Add the initial RealityKit content if let immersiveContentEntity = try? await Entity(named: "Immersive", in: realityKitContentBundle) { content.add(immersiveContentEntity) } NotificationCenter.default.addObserver( forName: NSNotification.Name.GCControllerDidConnect, object: nil, queue: nil) { _ in print("Handling GCControllerDidConnect notification") } } .modify { if #available(visionOS 2.0, *) { $0.handlesGameControllerEvents(matching: .gamepad) } else { $0 } } } } extension View { func modify<T: View>(@ViewBuilder _ modifier: (Self) -> T) -> some View { return modifier(self) } }

hello everyone. I got a texture loading error on visionOS 2.0: Can't create texture(Error Domain=MTKTextureLoaderErrorDomain Code=0 "Pixel format(MTLPixelFormatInvalid) is not valid on this device" UserInfo={NSLocalizedDescription=Pixel format(MTLPixelFormatInvalid) is not valid on this device, MTKTextureLoaderErrorKey=Pixel format(MTLPixelFormatInvalid) is not valid on this device} But this texture can load correctly on visionOS1.3. I don't know what happen between visionOS1.3 and visionOS2.0. The texture is a ktx file which stores cubemap that encoding in astc6x6hdr. And the ktx texture has a glInternalFormat info: GL_COMPRESSED_RGBA_ASTC_6x6. I wonder if visionOS2.0 no longer supports astc6x6hdr cubemap format, or there is something wrong with my assets.

What are the specific characteristics that trigger Game Mode in an iOS game? I have several casual SpriteKit games in the App Store but only one of them triggers Game Mode. What does GCSupportsGameMode do when set to true? Will it trigger Game Mode or will the OS still decide by itself?

Apple's own USDZ files from their website does not display properly both in OPReview and in Keynote when imported. It displays properly, however, in Reality Converter bit with this error: "Invalid USD shader node in USD file Shader nodes must have “id” as the implementationSource, with id values that begin with “Usd”. Also, shader inputs with connections must each have a single, valid connection source." I tried importing other models from external sources and they work without any issue at all. Is there any potential fix or workaround this? Thanks in advance.

I use xcode16 and swiftUI for programming on a macos15 system. There is a problem. When I render a picture through mtkview, it is normal when displayed on a regular view. However, when the view is displayed through the .sheet method, the image cannot be displayed. There is no error message from xcode. import Foundation import MetalKit import SwiftUI struct CIImageDisplayView: NSViewRepresentable { typealias NSViewType = MTKView var ciImage: CIImage init(ciImage: CIImage) { self.ciImage = ciImage } func makeNSView(context: Context) -&gt; MTKView { let view = MTKView() view.delegate = context.coordinator view.preferredFramesPerSecond = 60 view.enableSetNeedsDisplay = true view.isPaused = true view.framebufferOnly = false if let defaultDevice = MTLCreateSystemDefaultDevice() { view.device = defaultDevice } view.delegate = context.coordinator return view } func updateNSView(_ nsView: MTKView, context: Context) { } func makeCoordinator() -&gt; RawDisplayRender { RawDisplayRender(ciImage: self.ciImage) } class RawDisplayRender: NSObject, MTKViewDelegate { // MARK: Metal resources var device: MTLDevice! var commandQueue: MTLCommandQueue! // MARK: Core Image resources var context: CIContext! var ciImage: CIImage init(ciImage: CIImage) { self.ciImage = ciImage self.device = MTLCreateSystemDefaultDevice() self.commandQueue = self.device.makeCommandQueue() self.context = CIContext(mtlDevice: self.device) } func mtkView(_ view: MTKView, drawableSizeWillChange size: CGSize) {} func draw(in view: MTKView) { guard let currentDrawable = view.currentDrawable, let commandBuffer = commandQueue.makeCommandBuffer() else { return } let dSize = view.drawableSize let drawImage = self.ciImage let destination = CIRenderDestination(width: Int(dSize.width), height: Int(dSize.height), pixelFormat: view.colorPixelFormat, commandBuffer: commandBuffer, mtlTextureProvider: { () -&gt; MTLTexture in return currentDrawable.texture }) _ = try? self.context.startTask(toClear: destination) _ = try? self.context.startTask(toRender: drawImage, from: drawImage.extent, to: destination, at: CGPoint(x: (dSize.width - drawImage.extent.width) / 2, y: 0)) commandBuffer.present(currentDrawable) commandBuffer.commit() } } } struct ShowCIImageView: View { let cii = CIImage.init(contentsOf: Bundle.main.url(forResource: "9-10", withExtension: "jpg")!)! var body: some View { CIImageDisplayView.init(ciImage: cii).frame(width: 500, height: 500).background(.red) } } struct ContentView: View { @State var showImage = false var body: some View { VStack { Image(systemName: "globe") .imageScale(.large) .foregroundStyle(.tint) Text("Hello, world!") ShowCIImageView() Button { showImage = true } label: { Text("showImage") } } .frame(width: 800, height: 800) .padding() .sheet(isPresented: $showImage) { ShowCIImageView() } } }

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) } }

I'm using the Apple RoomPlan sdk to generate a .usdz file, which works fine, and gives me a 3D scan of my room. But when I try to use Model I/O's MDLAsset to convert that output into an .obj file, it comes out as a completely flat model shaped like a rectangle. Here is my Swift code: let destinationURL = destinationFolderURL.appending(path: "Room.usdz") do { try FileManager.default.createDirectory(at: destinationFolderURL, withIntermediateDirectories: true) try finalResults?.export(to: destinationURL, exportOptions: .model) let newUsdz = destinationURL; let asset = MDLAsset(url: newUsdz); let obj = destinationFolderURL.appending(path: "Room.obj") try asset.export(to: obj) } Not sure what's wrong here. According to MDLAsset documentation, .obj is a supported format and exporting from .usdz to the other formats like .stl and .ply works fine and retains the original 3D shape. Some things I've tried: changing "exportOptions" to parametric, mesh, or model. simply changing the file extension of "destinationURL" (throws error)

I have an app which have an Immersive Space view and it needs the user to have a button in the bottom which have a fixed place in front of the user head like a dashboard in game or so but when the user get too close to any3d object in the view it could cover the button and make it inaccessible and it mainly would prevent the app for being approved like that in appstoreconnect I was working before on SceneKit and there was something like camera view Znear and Zfar which decide when to hide the 3d model if it comes too close or gets too far and I wonder if there is something like that in realityView / RealityKit 4. Here is My Code and the screenshots follows import SwiftUI import RealityKit struct ContentView: View { @State var myHead: Entity = { let headAnchor = AnchorEntity(.head) headAnchor.position = [-0.02, -0.023, -0.24] return headAnchor }() @State var clicked = false var body: some View { RealityView { content, attachments in // create a 3d box let mainBox = ModelEntity(mesh: .generateBox(size: [0.1, 0.1, 0.1])) mainBox.position = [0, 1.6, -0.3] content.add(mainBox) content.add(myHead) guard let attachmentEntity = attachments.entity(for: "Dashboard") else {return} myHead.addChild(attachmentEntity) } attachments: { // SwiftUI Inside Immersivre View Attachment(id: "Dashboard") { VStack { Spacer() .frame(height: 300) Button(action: { goClicked() }) { Text(clicked ? "⏸️" : "▶️") .frame(maxWidth: 48, maxHeight: 48, alignment: .center) .font(.extraLargeTitle) } .buttonStyle(.plain) } } } } func goClicked() { clicked.toggle() } }

Hi, I am trying to use PhotogrammetrySample input sequence according to the WWDC video. I modified only the following code in the sample: var images = try FileManager.default.contentsOfDirectory(at: captureFolderManager.imagesFolder, includingPropertiesForKeys: nil, options: .skipsHiddenFiles) let inputSequence = images.lazy.compactMap { file in return self.loadSampleAndMask(file: file) } // Next line causes the exception photogrammetrySession = try PhotogrammetrySession( input: inputSequence, configuration: configuration) private func loadSampleAndMask(file: URL) -> PhotogrammetrySample? { do { var sample = try PhotogrammetrySample(contentsOf: file) return sample } catch { return nil } } I am getting following runtime error: Thread 1: EXC_BREAKPOINT (code=1, subcode=0x240d88904)

Hello. I have an application that exports a 3D object with vertex color to USDC. I'm using an MDLAsset and its functionality to export to USDC with [asset exportAssetToURL:[NSURL fileURLWithPath:filePath]]. In version 1.3 of the system, everything works correctly. But after updating to version 2.0, the exported object appears white (using the same code). Any suggestions? Thank you very much.

If I import a USDZ model with blendMode set to alpha, occlusion does not work on iPhone with iOS 18. How should transparent materials and occlusion be properly used in the new RealityKit? Additionally, new artifacts have appeared when working with transparent objects overlapping each other. The transparency results do not blend but rather parts of the model just not rendering.

I have followed the documentation to download the UnityPlugins from https://github.com/apple/unityplugins. When I run through the quick guide to create the .tgz builds it builds all the packages except for the Apple.GameKit package, which is the one I need. It looks like during the build process there is a build failure which is likely causing this issue I will post the code below. This is blocking me and I have tried multiple times to the same result. (I removed some of the code error because it was too long just showing start and finish) Building Release GameKit native libraries for platform: iOS Build command: xcodebuild -scheme iOS - Release -destination generic/platform=iOS clean build ** BUILD FAILED ** The following build commands failed: SwiftCompile normal arm64 Compiling\ GKAchievementDescription.swift,\ GKLeaderboard.swift,\ GKTurnBasedMatchmakerViewControllerDelegate.swift,\ GKChallengeDelegate.swift,\ GKMatchDelegate.swift,\ GKMatchmakerViewControllerDelegate.swift,\ GKInvite.swift,\ GKChallenge.swift,\ DefaultHandlers.swift,\ GKTurnBasedParticipant.swift,\ GKLocalPlayerListener.swift,\ GKGameCenterViewController.swift,\ GKSavedGameDelegate.swift,\ GKAccessPoint.swift,\ GKBasePlayer.swift,\ GKAchievementChallenge.swift,\ GKLeaderboardEntry.swift,\ GKTurnBasedExchangeReply.swift,\ GKTurnBasedMatchmakerViewController.swift,\ AppleCoreRuntimeShared.swift,\ GKErrorCodeExtension.swift,\ GKMatchmaker.swift,\ GKTurnBasedExchange.swift,\ GKNotificationBanner.swift,\ GKScoreChallenge.swift,\ GKLocalPlayer.swift,\ GKLeaderboardSet.swift,\ GKSavedGame.swift,\ GKMatchRequest.swift,\ GKMatch.swift,\ GKAchievement.swift,\ GKVoiceChat.swift,\ GKTurnBasedMatchDelegate.swift,\ UiUtilities.swift,\ GKTurnBasedMatch.swift,\ GKMatchmakerViewController.swift,\ GameKitUIDelegateHandler.swift,\ GKPlayer.swift,\ GKInviteDelegate.swift /Users/brookehowell/Downloads/apple/unityplugins/plug-ins/Apple.GameKit/Native/GameKitWrapper/GKAchievementDescription.swift /Users/brookehowell/Downloads/apple/unityplugins/plug-ins/Apple.GameKit/Native/GameKitWrapper/GKLeaderboard.swift /Users/brookehowell/Downloads/apple/unityplugins/plug-ins/Apple.GameKit/Native/GameKitWrapper/GKTurnBasedMatchmakerViewControllerDelegate.swift /Users/brookehowell/Downloads/apple/unityplugins/plug-ins/Apple.GameKit/Native/GameKitWrapper/GKChallengeDelegate.swift /Users/brookehowell/Downloads/apple/unityplugins/plug-ins/Apple.GameKit/Native/GameKitWrapper/GKMatchDelegate.swift /Users/brookehowell/Downloads/apple/unityplugins/plug-ins/Apple.GameKit/Native/GameKitWrapper/GKMatchmakerViewControllerDelegate.swift /Users/brookehowell/Downloads/apple/unityplugins/plug-ins/Apple.GameKit/Native/GameKitWrapper/GKInvite.swift /Users/brookehowell/Downloads/apple/unityplugins/plug-ins/Apple.GameKit/Native/GameKitWrapper/GKChallenge.swift /Users/brookehowell/Downloads/apple/unityplugins/plug-ins/Apple.GameKit/Native/GameKitWrapper/DefaultHandlers.swift /Users/brookehowell/Downloads/apple/unityplugins/plug-ins/Apple.GameKit/Native/GameKitWrapper/GKTurnBasedParticipant.swift /Users/brookehowell/Downloads/apple/unityplugins/plug-ins/Apple.GameKit/Native/GameKitWrapper/GKLocalPlayerListener.swift /Users/brookehowell/Downloads/apple/unityplugins/plug-ins/Apple.GameKit/Native/GameKitWrapper/GKGameCenterViewController.swift /Users/brookehowell/Downloads/apple/unityplugins/plug-ins/Apple.GameKit/Native/GameKitWrapper/GKSavedGameDelegate.swift /Users/brookehowell/Downloads/apple/unityplugins/plug-ins/Apple.GameKit/Native/GameKitWrapper/GKAccessPoint.swift /Users/brookehowell/Downloads/apple/unityplugins/plug-ins/Apple.GameKit/Native/GameKitWrapper/GKBasePlayer.swift /Users/brookehowell/Downloads/apple/unityplugins/plug-ins/Apple.GameKit/Native/GameKitWrapper/GKAchievementChallenge.swift /Users/brookehowell/Downloads/apple/unityplugins/plug-ins/Apple.GameKit/Native/GameKitWrapper/GKLeaderboardEntry.swift /Users/brookehowell/Downloads/apple/unityplugins/plug-ins/Apple.GameKit/Native/GameKitWrapper/GKTurnBasedExchangeReply.swift /Users/brookehowell/Downloads/apple/unityplugins/plug-ins/Apple.GameKit/Native/GameKitWrapper/GKTurnBasedMatchmakerViewController.swift /Users/brookehowell/Downloads/apple/unityplugins/plug-ins/Apple.GameKit/Native/GameKitWrapper/AppleCoreRuntimeShared.swift /Users/brookehowell/Downloads/apple/unityplugins/plug-ins/Apple.GameKit/Native/GameKitWrapper/GKErrorCodeExtension.swift /Users/brookehowell/Downloads/apple/unityplugins/plug-ins/Apple.GameKit/Native/GameKitWrapper/GKMatchmaker.swift /Users/brookehowell/Downloads/apple/unityplugins/plug-ins/Apple.GameKit/Native/GameKitWrapper/GKTurnBasedExchange.swift /Users/brookehowell/Downloads/apple/unityplugins/plug-ins/Apple.GameKit/Native/GameKitWrapper/GKNotificationBanner.swift /Users/brookehowell/Downloads/apple/unityplugins/plug-ins/Apple.GameKit/Native/GameKitWrapper/GKScoreChallenge.swift /Users/brookehowell/Downloads/apple/unityplugins/plug-ins/Apple.GameKit/Native/GameKitWrapper/GKLocalPlayer.swift /Users/brookehowell/Downloads/apple/unityplugins/plug-ins/Apple.GameKit/Native/GameKitWrapper/GKLeaderboardSet.swift /Users/brookehowell/Downloads/apple/unityplugins/plug-ins/Apple.GameKit/Native/GameKitWrapper/GKSavedGame.swift /Users/brookehowell/Downloads/apple/unityplugins/plug-ins/Apple.GameKit/Native/GameKitWrapper/GKMatchRequest.swift /Users/brookehowell/Downloads/apple/unityplugins/plug-ins/Apple.GameKit/Native/GameKitWrapper/GKMatch.swift /Users/brookehowell/Downloads/apple/unityplugins/plug-ins/Apple.GameKit/Native/GameKitWrapper/GKAchievement.swift /Users/brookehowell/Downloads/apple/unityplugins/plug-ins/Apple.GameKit/Native/GameKitWrapper/GKVoiceChat.swift /Users/brookehowell/Downloads/apple/unityplugins/plug-ins/Apple.GameKit/Native/GameKitWrapper/GKTurnBasedMatchDelegate.swift /Users/brookehowell/Downloads/apple/unityplugins/plug-ins/Apple.GameKit/Native/GameKitWrapper/UiUtilities.swift /Users/brookehowell/Downloads/apple/unityplugins/plug-ins/Apple.GameKit/Native/GameKitWrapper/GKTurnBasedMatch.swift /Users/brookehowell/Downloads/apple/unityplugins/plug-ins/Apple.GameKit/Native/GameKitWrapper/GKMatchmakerViewController.swift /Users/brookehowell/Downloads/apple/unityplugins/plug-ins/Apple.GameKit/Native/GameKitWrapper/GameKitUIDelegateHandler.swift /Users/brookehowell/Downloads/apple/unityplugins/plug-ins/Apple.GameKit/Native/GameKitWrapper/GKPlayer.swift /Users/brookehowell/Downloads/apple/unityplugins/plug-ins/Apple.GameKit/Native/GameKitWrapper/GKInviteDelegate.swift (in target 'GameKitWrapper iOS' from project 'GameKitWrapper') CompileSwift normal arm64 (in target 'GameKitWrapper iOS' from project 'GameKitWrapper') (2 failures)

The following code runs fine when compiled with Swift 5, but crashes when compiled with Swift 6 (stack trace below). In the draw method, commenting out the addCompletedHandler line fixes the problem. I'm testing on iOS 18.0 and see the same behavior in both the simulator and on a device. What's going on here? import Metal import MetalKit import UIKit class ViewController: UIViewController { @IBOutlet var metalView: MTKView! private var commandQueue: MTLCommandQueue? override func viewDidLoad() { super.viewDidLoad() guard let device = MTLCreateSystemDefaultDevice() else { fatalError("expected a Metal device") } self.commandQueue = device.makeCommandQueue() metalView.device = device metalView.enableSetNeedsDisplay = true metalView.isPaused = true metalView.delegate = self } } extension ViewController: MTKViewDelegate { func mtkView(_ view: MTKView, drawableSizeWillChange size: CGSize) {} func draw(in view: MTKView) { guard let commandQueue, let commandBuffer = commandQueue.makeCommandBuffer() else { return } commandBuffer.addCompletedHandler { _ in } // works with Swift 5, crashes with Swift 6 commandBuffer.commit() } } Here's the stack trace: Thread 10 Queue : connection Queue (serial) #0 0x000000010581c3f8 in _dispatch_assert_queue_fail () #1 0x000000010581c384 in dispatch_assert_queue () #2 0x00000002444c63e0 in swift_task_isCurrentExecutorImpl () #3 0x0000000104d71ec4 in closure #1 in ViewController.draw(in:) () #4 0x0000000104d71f58 in thunk for @escaping @callee_guaranteed (@guaranteed MTLCommandBuffer) -> () () #5 0x0000000105ef1950 in __47-[CaptureMTLCommandBuffer _preCommitWithIndex:]_block_invoke_2 () #6 0x00000001c50b35b0 in -[MTLToolsCommandBuffer invokeCompletedHandlers] () #7 0x000000019e94d444 in MTLDispatchListApply () #8 0x000000019e94f558 in -[_MTLCommandBuffer didCompleteWithStartTime:endTime:error:] () #9 0x000000019e95352c in -[_MTLCommandQueue commandBufferDidComplete:startTime:completionTime:error:] () #10 0x0000000226ef50b0 in handleMainConnectionReplies () #11 0x00000001800c9690 in _xpc_connection_call_event_handler () #12 0x00000001800cad90 in _xpc_connection_mach_event () #13 0x000000010581a86c in _dispatch_client_callout4 () #14 0x0000000105837950 in _dispatch_mach_msg_invoke () #15 0x0000000105822870 in _dispatch_lane_serial_drain () #16 0x0000000105838c10 in _dispatch_mach_invoke () #17 0x0000000105822870 in _dispatch_lane_serial_drain () #18 0x00000001058237b0 in _dispatch_lane_invoke () #19 0x00000001058301f0 in _dispatch_root_queue_drain_deferred_wlh () #20 0x000000010582f75c in _dispatch_workloop_worker_thread () #21 0x00000001050abb74 in _pthread_wqthread ()