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GameKit Leaderboards not working in iOS 26.2
Leaderboards working fine in iOS 26.1 but seem to be broken in 26.2 and also in the 26.3 developer beta. Players cannot submit scores and neither can they view scores on Apple's default leaderboards. Custom leaderboards that rely on pulling information using GameKit APIs also fail. Is there a workaround or patch for this?
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421
Jan ’26
Metal 4 Argument Tables
I am puzzled by the setAddress(_:attributeStride:index:) of MTL4ArgumentTable. Can anyone please explain what the attributeStride parameter is for? The doc says that it is "The stride between attributes in the buffer." but why? Who uses this for what? On the C++ side in the shaders the stride is determined by the C++ type, as far as I know. What am I missing here? Thanks!
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1k
Jan ’26
Reality Composer Pro Transparent Textures
Hey everyone, I am currently developing an app in visionOS and using RealityComposerPro create scenes in put in my app. I have a humanoid model with hair strands, and each strand of hair has an opacity map. However, some reflections are still visible even though the opacity is zero. There are also some weird culling among hair strands (in the left circle) and weird reflections in hair cards (in the right circle). Here's my settings for the materials. Since all the hair strands are interconnected with each other, it is hard to decide the drawing order in Xcode, so I am wondering if there's an easier way to handle transparency objects. Please let me know if you know anything helpful, much appreciated!
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153
Apr ’25
How to use MTKTextureLoader to load png data
I am trying to load some PNG data with MTKTextureLoader newTextureWithData,but the result shows wrong at the alpha area. Here is the code. I have an image URL, after it downloads successfully, I try to use the data or UIImagePNGRepresentation (image), they all show wrong. UIImage *tempImg = [UIImage imageWithData:data]; CGImageRef cgRef = tempImg.CGImage; MTKTextureLoader *loader = [[MTKTextureLoader alloc] initWithDevice:device]; id<MTLTexture> temp1 = [loader newTextureWithData:data options:@{MTKTextureLoaderOptionSRGB: @(NO), MTKTextureLoaderOptionTextureUsage: @(MTLTextureUsageShaderRead), MTKTextureLoaderOptionTextureCPUCacheMode: @(MTLCPUCacheModeWriteCombined)} error:nil]; NSData *tempData = UIImagePNGRepresentation(tempImg); id<MTLTexture> temp2 = [loader newTextureWithData:tempData options:@{MTKTextureLoaderOptionSRGB: @(NO), MTKTextureLoaderOptionTextureUsage: @(MTLTextureUsageShaderRead), MTKTextureLoaderOptionTextureCPUCacheMode: @(MTLCPUCacheModeWriteCombined)} error:nil]; id<MTLTexture> temp3 = [loader newTextureWithCGImage:cgRef options:@{MTKTextureLoaderOptionSRGB: @(NO), MTKTextureLoaderOptionTextureUsage: @(MTLTextureUsageShaderRead), MTKTextureLoaderOptionTextureCPUCacheMode: @(MTLCPUCacheModeWriteCombined)} error:nil]; }] resume];
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675
May ’25
xCode26.x Metal4 classes do not compile
Hi, I am using xCode26.x. But my Metal4 classes are not compiling. I downloaded the sample code from Apple's website - https://developer.apple.com/documentation/Metal/processing-a-texture-in-a-compute-function. For example, I am getting errors like "Cannot find protocol declaration for 'MTL4CommandQueue'; I have hit a deadline. Any recommendations are very welcome. I have downloaded the Metal Tool chain. When I run the following commands on the terminal - xcodebuild -showComponent metalToolchain ; xcrun -f metal ; xcrun metal --version I get the following response - Asset Path: /System/Library/AssetsV2/com_apple_MobileAsset_MetalToolchain/86fbaf7b114a899754307896c0bfd52ffbf4fded.asset/AssetData Build Version: 17A321 Status: installed Toolchain Identifier: com.apple.dt.toolchain.Metal.32023 Toolchain Search Path: /Users/private/Library/Developer/DVTDownloads/MetalToolchain/mounts/86fbaf7b114a899754307896c0bfd52ffbf4fded /Users/private/Library/Developer/DVTDownloads/MetalToolchain/mounts/86fbaf7b114a899754307896c0bfd52ffbf4fded/Metal.xctoolchain/usr/bin/metal Apple metal version 32023.830 (metalfe-32023.830.2) Target: air64-apple-darwin24.6.0 Thread model: posix InstalledDir: /Users/private/Library/Developer/DVTDownloads/MetalToolchain/mounts/86fbaf7b114a899754307896c0bfd52ffbf4fded/Metal.xctoolchain/usr/metal/current/bin
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1.1k
Jan ’26
How to add and remove child entities to a rigged entity in RealityKit?
I am currently using RealityKit (perspective camera) to render a character in my swiftUI app. The character has customization such as clothing items and hair and all objects are properly weighted to the rig. The way the model is setup in Blender is like so: Groups of objects that will be swapped (ex: Shoes -> Shoes objects) and an armature. I then export it to usdc with all objects active. This is the resulting hierarchy: Before exporting for the animation (armature modifier applied), I simply had to store the Model entities and swap them in but now when I export with the Armature Modifier applied, so that animations get exported, the ModelComponent gets flattened to the armature and swapping entities and applying new materials to them is no longer as simple. Here's a demo blend file and usdc export with a setup like mine, having an animated bone to swing a cube and sphere, to be swapped so that only one is visible https://www.dropbox.com/scl/fo/be2q6qcztc83z7c4gj1w0/AMapxWc_ip2KZ8oTOYDUMv8?rlkey=rcdaggcxq06dyen09mw5mqmem&st=bnc0d7j0&dl=0 This is how I'm loading the entity and removing a part, with the demo files import SwiftUI import RealityKit struct SwapDemoView: View { var body: some View { RealityView { content in let camera = PerspectiveCamera() camera.transform.translation = SIMD3(x: 0, y: 0.1, z: 3) guard let root = try? await Entity(named: "simpleSwapDemo") else { fatalError("simpleSwapDemo.usdc is not present") } print(root) // Get initial hierarchy guard let cube = root.findEntity(named: "Cube") else { fatalError("Entity cube doesn't exist") } cube.removeFromParent() // <-- Cube is still visible after removal print(root) // Get hierarchy to confirm removal of cube let resource = root.availableAnimations[0] root.playAnimation(resource.repeat()) content.add(root) content.add(camera) } .background(.white) } } And this is what the entity hierarchy looks like in RealityKit before cube removal ▿ 'root' : Entity, children: 1 ⟐ SynchronizationComponent ⟐ AnimationLibraryComponent ⟐ Transform ▿ 'Armature' : ModelEntity, children: 2 ⟐ SynchronizationComponent ⟐ ModelComponent ⟐ SkeletalPosesComponent ⟐ AnimationLibraryComponent ⟐ Transform ▿ 'Armature' : Entity ⟐ SynchronizationComponent ⟐ Transform ▿ 'Primitives' : Entity, children: 2 ⟐ SynchronizationComponent ⟐ Transform ▿ 'Sphere' : Entity, children: 1 ⟐ SynchronizationComponent ⟐ Transform ▿ 'Sphere' : Entity ⟐ SynchronizationComponent ⟐ Transform ▿ 'Cube' : Entity, children: 1 ⟐ SynchronizationComponent ⟐ Transform ▿ 'Cube' : Entity ⟐ SynchronizationComponent ⟐ Transform And here's the hierarchy after removal ▿ 'root' : Entity, children: 1 ⟐ SynchronizationComponent ⟐ AnimationLibraryComponent ⟐ Transform ▿ 'Armature' : ModelEntity, children: 2 ⟐ SynchronizationComponent ⟐ ModelComponent ⟐ SkeletalPosesComponent ⟐ AnimationLibraryComponent ⟐ Transform ▿ 'Armature' : Entity ⟐ SynchronizationComponent ⟐ Transform ▿ 'Primitives' : Entity, children: 1 ⟐ SynchronizationComponent ⟐ Transform ▿ 'Sphere' : Entity, children: 1 ⟐ SynchronizationComponent ⟐ Transform ▿ 'Sphere' : Entity ⟐ SynchronizationComponent ⟐ Transform And this is the result: What's the best practice here? Should animation be exported separately and then applied to the skeleton? If so, how is that achieved? I'm not really sure how to proceed here.
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143
May ’25
MTLCaptureManager.sharedCaptureManager generates corrupted .gputrace files (0KB, invalid internal structure)
Hello, I am experiencing an issue with programmatically capturing a GPU trace using MTLCaptureManager. The .gputrace file that is generated appears to be corrupted, and I'm looking for guidance or a solution. Description of the Problem: I am using MTLCaptureManager.sharedCaptureManager to capture a Metal frame and save it to disk. The generated .gputrace file is consistently reported as 0 bytes in size by the file system. Crucially, when I compress this 0-byte .gputrace file into a .zip archive, the resulting archive contains the full, expected data. After unzipping, the file can be opened and viewed correctly in Xcode. However,When inspecting the file's contents using NSFileManager in Objective-C (treating it as a directory), the internal structure is different from a .gputrace file captured directly from Xcode's Metal Debugger. capture in xcode capture in file Finally,When capturing multiple frames programmatically, the first captured frame contains valid buffer data. However, for subsequent frames (starting from the second frame), the corresponding buffer contents are all zero-filled. Frame 1: All MTLBuffer data is correctly captured and populated. Frame 2 and onward: The same MTLBuffer objects are present in the trace, but their contents are entirely 0 (i.e., the data is not captured or is corrupted). In this case, the on-screen display is normal, but the captured frame is incorrect. The frame captured directly in Xcode is also correct. Only the frame captured to a file is abnormal.
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521
Aug ’25
Threadgroup memory for fragment shader
Hello I am trying to get thread group memory access in fragment shader. In essence, I would like to have all the fragments in a tile to bitwiseOR some value. My idea was to use simd_or across the SIMD group, then make each SIMD group thread 0 to atomic or the value into thread group memory. Finally very first thread of the tile would be tasked with writing the value down to texture with write access. Now, I can allocate the thread group memory argument to the fragment function all right. MTLRenderEncoder has setThreadgroupMemoryLength call, which I am using the following way [renderEncoder setThreagroupMemoryLength: 16 offset: 0 atIndex:0] Unfortunately, all I am getting is the following error (runtime assertion) -[MTLDebugRenderCommandEncoder setThreadgroupMemoryLength:offset:atIndex:]:3487: failed assertion Set Threadgroup Memory Length Validation offset + length(16) must be <= threadgroupMemoryLength(0).` What I am doing wrong? How I can get thread group memory in the fragment shader? I know I could use tile shading and compute function but the problem is that here I really like to use fragment stuff. Will be grateful for help.
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115
Apr ’25
PhotogrammetrySession crashes after update from iOS 18 to iOS 26
After updating iPad/iPhone devices from iOS 18 to iOS 26, PhotogrammetrySession intermittently crashes during photogrammetry processing. The same workflow was stable on iOS 18 with no code changes to the app. Environment: OS versions: Works on OS 18, crashes on OS 26 Device: iPad/iPhone (reproducible across devices) Source images: ~170-200 JPG files at 2160 x 3840 resolution Reproduction: The crash occurs consistently on the second or third sequential run of the photogrammetry session with the same image set. First run typically succeeds. Crash details: Xcode shows an uncaught exception during image processing: terminating due to uncaught exception of type std::bad_alloc: std::bad_alloc VTPixelTransferSession 420f sid 269 (2160.00 x 3840.00) [0.00 0.00 2160 3840] rowbytes( 2160, 2160 ) Color( (null), 0x0, (null), (null), ITU_R_601_4 ) => 24 sid 19 (2160.00 x 3840.00) [0.00 0.00 2160 3840] rowbytes( 6528 ) Color( 0x0, (null), (null), (null) ) This appears to be a memory allocation failure in VTPixelTransferSession during color space conversion. Has anyone else experienced similar crashes with CorePhotogrammetry on iOS 26, or found workarounds?
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368
Dec ’25
Improving person segmentation and occlusion quality in RealityKit
I’m building an app that uses RealityKit and specifically ARConfiguration.FrameSemantics.personSegmentationWithDepth. The goal is to insert an AR object into the scene behind a person, and an additional AR object in front of the person, while being as photo realistic as possible. Through testing, I’ve noticed that many times, the edges of the person segmentation mask are not well matched to the actual person, and parts of the person are transparent, with the AR object bleeding through. It’s sort of like a “bad green screen” effect, which I’d expect to see a little bit, but not to this extent. I’ve been testing on iPhone 16, iPhone 14 Pro, iPad Pro 12.9 inch 6th Generation, and iPhone 12 Pro, with similar results across all devices. I’m wondering what else I can do to improve this… either code changes, platform (like different iPhone models), or environment (like lighting, distance, etc). Attaching some example screen grabs and a minimum reproducible code sample. Appreciate any insights! import ARKit import SwiftUI import RealityKit struct RealityViewContainer: UIViewRepresentable { func makeUIView(context: Context) -> ARView { let arView = ARView(frame: .zero) arView.environment.sceneUnderstanding.options.insert(.occlusion) arView.renderOptions.insert(.disableMotionBlur) arView.renderOptions.insert(.disableDepthOfField) let configuration = ARWorldTrackingConfiguration() configuration.planeDetection = [.horizontal] if ARWorldTrackingConfiguration.supportsFrameSemantics(.personSegmentationWithDepth) { configuration.frameSemantics.insert(.personSegmentationWithDepth) } arView.session.run(configuration) arView.session.delegate = context.coordinator context.coordinator.arView = arView } func makeCoordinator() -> Coordinator { Coordinator(self) } class Coordinator: NSObject, ARSessionDelegate { var parent: RealityViewContainer var floorAnchor: ARPlaneAnchor? init(_ parent: RealityViewContainer) { self.parent = parent } func session(_ session: ARSession, didAdd anchors: [ARAnchor]) { if let arView,floorAnchor == nil { for anchor in anchors { if let horizontalPlaneAnchor = anchor as? ARPlaneAnchor, horizontalPlaneAnchor.alignment == .horizontal, horizontalPlaneAnchor.transform.columns.3.y < arView.cameraTransform.translation.y { // filter out ceiling floorAnchor = horizontalPlaneAnchor let backgroundEntity = BackgroundEntity() let anchorEntity = AnchorEntity(anchor: horizontalPlaneAnchor) anchorEntity.addChild(background) let foregroundEntity = ForegroundEntity() backgroundEntity.addChild(foregroundEntity) arView.scene.addAnchor(anchorEntity) arView.installGestures([.rotation, .translation], for: backgroundEntity) break // Stop after adding the first horizontal plane (floor) } } } } } }
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116
May ’25
Walking an entity around an immersive space in visionOS like the window drag bar
I'm trying to understand how Apple handles dragging windows around in an immersive space. 3d Gestures seem to be only half of the solution in that they are great if you're standing still and want to move the window an exaggerated amount around the environment, but if you then start walking while dragging, the amplified gesture sends the entity flying off into the distance. It seems they quickly transition from one coordinate system to another depending on if the user is physically moving. If you drag a window and start walking the movement suddenly matches your speed. When you stop moving, you can push and pull the windows around again like a super hero. Am I missing something obvious in how to copy this behavior? Hello world, which uses the 3d gesture has the same problem. You can move the world around but if you walk with it, it flies off. Are they tracking the head movement and if it's moved more than a certain amount it uses that offset instead? Is there anything out of the box that can do this before I try and hack my own solution?
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1.2k
Dec ’25
iOS Metal system delayed one Vsync period to really display the frame on the screen
View Layout Add the following views in a view controller: Label View A, with a subview of the same size: MTKView A View B, with a subview of the same size: MTKView B Refresh Rates of Each View The label view refreshes at 60fps (driven by CADisplayLink). MTKView A and B refresh at 15fps. MTKView Implementation Details The corresponding CAMetalLayer's maximumDrawableCount is set to 2, changed to double buffering. The scheduling mechanism is modified; drawing is not driven by the internal loop but is done manually. The draw call is triggered immediately upon receiving a frame. self.metalView.enableSetNeedsDisplay = NO; self.metalView.paused = YES; A new high-priority queue is created for drawing, instead of handling it on the main queue. MTKView Latency Tracking The GPU completion time T1 is observed through the addCompletedHandler callback of the CommandBuffer. The presentation time T2 of the frame is observed through the addPresentedHandler callback of the currentDrawable in MTKView. Testing shows that T2 - T1 > 16.6ms (the Vsync period at 60Hz). This means that after the GPU rendering in MTLView is finished, the frame is not actually displayed at the next Vsync instruction but only at the Vsync instruction after that. I believe there is an extra 16.6ms of latency here, which I want to eliminate by adjusting the rendering mechanism. Observation from Instruments From Instruments, the Surface presentation aligns with the above test results. After the Metal encoder finishes, the Surface in Display switches only after the next-next Vsync instruction. See the image in the link for details. Questions According to a beginner's understanding, after MTKView's GPU rendering is finished, the next Vsync instruction should officially display (make it visible). However, this is not what is observed. Does the subview MTKView need to wait for another Vsync cycle to be drawn to the actual display buffer? The label updates its text at 60fps, so the entire interface should be displayed at 60fps. Is the content of MTKView not synchronized when the display happens? Explanation of the Reasoning Behind Some MTKView Code Details Changing from the default triple buffering to double buffering helps reduce the latency introduced by rendering. Not using MTKView's own scheduling mechanism but using manual triggering of the draw method is because MTKView's own scheduling mechanism is driven by CADisplayLink. Therefore, if a frame falls within a Vsync window, it needs to wait for the next Vsync window to trigger the draw operation, which introduces waiting latency.
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587
Dec ’25
Is there a way to get all the turnbasematches that can join
I am using Unity's GameKit to implement a turnbase game. I want to make a UI in Unity to show all the games I can join. I tried using var matches = await GKTurnBasedMatch.LoadMatches(); to get all the open matches. But it seems that I can only get the matcm related to the current apple account. Can you help me get all the matches? ALSO I used var match = await GKTurnBasedMatchmakerViewController.Request(request); to exit the gamecenter interface and start a game (automatic matching, no one was invited) Another device used var match = await GKTurnBasedMatch.Find(request); to find the game, but it did not find the game, but it start a new game (automatic matching). Can you help me solve these problems?
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304
Mar ’25
GKLeaderboard.loadLeaderboards returns empty array
After authenticating the user I'm loading my Game Center leaderboards like this: let leaderboards = try await GKLeaderboard.loadLeaderboards(IDs: [leaderboardID]) This is working fine, but there are times when this just returns an empty array. When I encounter this situation, the array remains empty for several hours when retrying, but then at some point it suddenly starts working again. Is this a known issue? Or am I hitting some kind of quota maybe (as I do it quite often while developing my game)?. Edit: My leaderboards are grouped in sets if that makes any difference here.
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513
Dec ’25
Why does game mode not get triggered for my App?
I think I really have tried everything and I did all according to official documentation to support game mode on iOS or iPadOS but it doesn't matter what I do it just doesn't get triggered. Funny enough it works during development when I install it via Xcode but as soon as it is live on the store and when I install it from there game mode doesn't get triggered anymore. What I have atm I have added (even though it is deprecated) <key>GCSupportsGameMode</key> <true/> I have set the (but it seems only supported for macOS) <key>LSApplicationCategoryType</key> <string>public.app-category.games</string> I have added <key>LSSupportsGameMode</key> <true/> It just doesn't work. Is there anything else what needs to be done? Should the flag LSSupportsGameMode not be enough normally? The reason why this is so annoying is that my app is a real time streaming app and I want to profit from minimised background activities for smoother gameplay and more consistent frame rates like mentioned in the documentation.
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673
Nov ’25
Game Porting Toolkit installation fails: CMake compatibility error in game-porting-toolkit-compiler
I'm encountering a build failure when trying to install the Game Porting Toolkit via Homebrew. The installation fails during the game-porting-toolkit-compiler dependency build phase with a CMake compatibility error. Error Message: CMake Error at CMakeLists.txt:3 (cmake_minimum_required): Compatibility with CMake < 3.5 has been removed from CMake. Update the VERSION argument <min> value. Or, use the <min>...<max> syntax to tell CMake that the project requires at least <min> but has been updated to work with policies introduced by <max> or earlier. Or, add -DCMAKE_POLICY_VERSION_MINIMUM=3.5 to try configuring anyway. -- Configuring incomplete, errors occurred! Environment: macOS: 15.6.1 (Sequoia) Homebrew: 5.0.1 CMake: 3.20.2 Architecture: x86_64 (via Rosetta) Formula: apple/apple/game-porting-toolkit-compiler v0.1 Source: crossover-sources-22.1.1.tar.gz Steps to Reproduce: Install x86_64 Homebrew for Rosetta compatibility Run: arch -x86_64 /usr/local/bin/brew install apple/apple/game-porting-toolkit Build fails during dependency installation Root Cause: The LLVM/Clang sources included in crossover-sources-22.1.1.tar.gz contain a CMakeLists.txt file that specifies a minimum CMake version lower than 3.5. Modern CMake versions (3.5+) have removed backward compatibility with these older version requirements. Potential Solutions: Update the Homebrew formula to patch the CMakeLists.txt with cmake_minimum_required(VERSION 3.5) or higher Update to newer CrossOver sources with updated CMake requirements Add the -DCMAKE_POLICY_VERSION_MINIMUM=3.5 flag to the CMake build command in the formula Is this a known issue? Are there plans to update the formula or the source package to resolve this compatibility problem? Any guidance on a workaround would be appreciated. Full log available at: /Users/kentarovadney/Library/Logs/Homebrew/game-porting-toolkit-compiler/02.cmake.log Thanks for any assistance!
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989
Nov ’25
screencapturekit
I have code that captures a window and displays a cropped image. The problem is 2 fold. Kit doesn't seem to allow to modify stop and recapture image in window mode to capture a portion of the screen. So this makes me having to crop and display the cropped image via a published variable. This all works find. But seems to stop after some time. Using an M1 16gig ram. program is taking less than 100meg of mem with 40-70%cpu as the crow flies. printing captured success in debug mode and sometimes frame isn't valid so guarding against it. any ideas on how to improve my strategy?
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141
Jun ’25