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'__abort_with_payload' from CompositorNonUI on visionOS 26.2 (device + simulator, Omniverse streaming)
I am developing a custom app for Apple Vision Pro using Compositor Services to stream content from NVIDIA Omniverse. The app is based on: https://github.com/NVIDIA-Omniverse/apple-configurator-sample Environment: Device: Apple Vision Pro OS Version: visionOS 26.2 Xcode Version: 26.2 The Issue: The application crashes hard (__abort_with_payload) in "libsystem_kernel.dylib" on Task 6 immediately after initialization. This appears to be a deliberate abort triggered by the compositor, not a typical crash. The issue occurs on both physical device and simulator. Important detail: The console output shows a specific CLIENT BUG assertion. By checking the metadata of the warning, I found that it is related to "Library: CompositorNonUI". Relevant console output before abort: Missed 'FrameLimiter' target of 90.0 Hz running compositor services to get IPD, FOV, etc fence tx observer 14f27 timed out after 0.600000 fence tx observer bc1b timed out after 0.600000 BUG IN CLIENT: For mixed reality experiences please use cp_drawable_compute_projection API
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SpriteKit Offline Rendering with SKRenderer
Hi! I'd like to share a technical sample app, SKRenderer Demo. This app demonstrates: Setting up SKRenderer Recording SpriteKit scenes to image sequences Recording SpriteKit scenes to video using IOSurface and AVFoundation Applying Core Image filters Exploring SpriteKit's simulation timing and physics determinism Use Case Record SpriteKit simulations as video or images for sharing and creating content. I explored several approaches, including the excellent view.texture(from:crop:) for live recording from SKView. The SKRenderer approach assumes recording happens asynchronously: you capture user interactions as commands during live interaction, then replay those commands through an offline render pass to generate the final output. I hope this helps others working on replay systems, simulation capture, or SpriteKit projects in general!
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TapGesture stops responding on ViewAttachmentComponent after disabling or removing and re-adding the Entity (visionOS 26)
Issue When an Entity with a ViewAttachmentComponent is: disabled using isEnabled = false removed using removeFromParent() and then enabled or added back again, the attached SwiftUI view is rendered correctly, but tap interactions stop working. Specifically: Button actions inside the attached view do not fire TapGesture closures on child views do not respond Expected Behavior Tap interactions inside the attached view should continue to work after the Entity is re-enabled or re-added. Actual Behavior After being disabled or removed once, all tap interactions stop responding. Comparison When displaying the same SwiftUI view using RealityViewAttachments, this issue does not occur. Removing and re-displaying the attachment still allows taps to work correctly. Reproduction Attached sample code reproduces the issue: A RealityView with an Entity that has a ViewAttachmentComponent The attached SwiftUI view contains a Toggle The toggle updates isEnabled on the Entity After toggling off and on, tap interactions stop responding Environment Xcode 26 visionOS 26 Question Is this expected behavior of ViewAttachmentComponent, or a bug? Is there a recommended way to temporarily hide or disable an Entity with ViewAttachmentComponent without breaking tap interactions? import SwiftUI import RealityKit struct GestureTestView: View { @State var sampleEnabled = true @State var sampleEntity: Entity? var body: some View { RealityView { contents, attachments in // After deleting and re-displaying it, taps no longer respond. let sample = Entity(components: ViewAttachmentComponent(rootView: SampleView())) // Executed successfully //let sample = attachments.entity(for: "SampleView")! contents.add(sample) sample.position = [0, 1.2, -1] sampleEntity = sample let toggleButton = Entity(components: ViewAttachmentComponent(rootView: ToggleButtonView(isOn: $sampleEnabled))) contents.add(toggleButton) toggleButton.position = [0, 1, -1] } update: { _, _ in // run update closure print(sampleEnabled) // update sample entity enable sampleEntity?.isEnabled = sampleEnabled } attachments: { Attachment(id: "SampleView") { SampleView() } } } } struct ToggleButtonView: View { @Binding var isOn: Bool var body: some View { VStack { Toggle(isOn: $isOn) { Text("Toggle") } } .padding() .glassBackgroundEffect() } } struct SampleView: View { var body: some View { VStack { Button { print("Hello, World!") } label: { Text("Hello, World!") .padding() } } .padding() .glassBackgroundEffect() } } #Preview(immersionStyle: .mixed) { GestureTestView() }
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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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995
Jan ’26
Hover effects w/ Compositor Services w/ PSVR2 controllers
Hi, I would like clarification on whether the new hover effects feature introduced in vision os 26 supported pinch gestures through the psvr 2 controllers. In your sample application, I was not able to confirm that this was working. Only pinch clicking with my hands worked. Pulling the trigger on the controller whilst looking at a 3d object did not activate the hover effect spatial event in the sample application. (The object is showing the highlight though) This is inconsistent with hover effect behavior with psvr2 controllers on swift ui views, where the trigger press does count as a button click. The sample I used was this one: https://developer.apple.com/documentation/compositorservices/rendering_hover_effects_in_metal_immersive_apps
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417
Jan ’26
Xcode Metal Trace
Code is download from apple official metal4 sample [https://developer.apple.com/documentation/metal/drawing-a-triangle-with-metal-4?language=objc] enable metal gpu trace in macOS schema and trace a frame in Xcode. Xcode may show segment fault on App from some 'GTTrace' function when click trace button. When replay a .gputrace file, Xcode may crash , throw an internal error or a XPC error. The example code using old metal-renderer can trace without any problem and everything works fine. Test Environment: Xcode Version 26.2 (17C52) macOS 26.2 (25C56) M1 Pro 16GB A2442
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Game Center When Opponent Declines Game
Turn-based games: 2 players When an opponent declines a game in the Game Center MatchMaker VC, that player sees that they quit, but no message is sent to the listener about that fact. For the person who started the match, their MMVC shows it's their turn again. Why doesn't Game Center end the match?
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461
Dec ’25
We are getting a blank image after capturing and compressing the picture.
We used below method to resize image while compress the image, Below method is correct or need to do the correction in method or "CGBitmapContextCreate" -(UIImage *)resizeImage:(UIImage *)anImage width:(int)width height:(int)height { CGImageRef imageRef = [anImage CGImage]; CGImageAlphaInfo alphaInfo = CGImageGetAlphaInfo(imageRef); if (alphaInfo == kCGImageAlphaNone) alphaInfo = kCGImageAlphaNoneSkipLast; CGContextRef bitmap = CGBitmapContextCreate(NULL, width, height, CGImageGetBitsPerComponent(imageRef), 4 * width, CGImageGetColorSpace(imageRef), alphaInfo); CGContextDrawImage(bitmap, CGRectMake(0, 0, width, height), imageRef); CGImageRef ref = CGBitmapContextCreateImage(bitmap); UIImage *result = [UIImage imageWithCGImage:ref]; CGContextRelease(bitmap); CGImageRelease(ref); return result; }
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Dec ’25
Metal recommendedMaxWorkingSetSize vs actual RAM on iPhone (LLM load fails)
Context I’m deploying large language models on iPhone using llama.cpp. A new iPhone Air (12 GB RAM) reports a Metal MTLDevice.recommendedMaxWorkingSetSize of 8,192 MB, and my attempt to load Llama-2-13B Q4_K (~7.32 GB weights) fails during model initialization. Environment Device: iPhone Air (12 GB RAM) iOS: 26 Xcode: 26.0.1 Build: Metal backend enabled llama.cpp App runs on device (not Simulator) What I’m seeing MTLCreateSystemDefaultDevice().recommendedMaxWorkingSetSize == 8192 MiB Loading Llama-2-13B Q4_K (7.32 GB) fails to complete. Logs indicate memory pressure / allocation issues consistent with the 8 GB working-set guidance. Smaller models (e.g., 7B/8B with similar quantization) load and run (8B Q4_K provide around 9 tokens/second decoding speed). Questions Is 8,192 MB an expected recommendedMaxWorkingSetSize on a 12 GB iPhone? What values should I expect on other 2025 devices including iPhone 17 (8 GB RAM) and iPhone 17 Pro (12 GB RAM) Is it strictly enforced by Metal allocations (heaps/buffers), or advisory for best performance/eviction behavior? Can a process practically exceed this for long-lived buffers without immediate Jetsam risk? Any guidance for LLM scenarios near the limit?
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510
Oct ’25
Bone deformation
I have been tasked with creating content for the Apple Vision Pro. Just the 3D content and animation, not the programming end of things. I can't seem to get any kind of mesh deformation animation to import into Reality Composer Pro. By that I mean bones/skin, or even point cache. I work on PC, and my main software is 3DS Max, but I'm borrowing an iMac for this job, and was instructed to use RCP on it for testing before handing things off to the programmer. My files open and play fine in other USD programs, like Omniverse, or USD View, just not Reality Composer Pro. I've seen the dinosaur demo in AVP, so I know mesh deformation is possible. If there are other essential tools that might make this possible, I have not been made aware of them. I am experimenting with bouncing things off of Blender, in case that exports better, but not really having luck there either -though my results are different. Thanks.
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Sep ’25
Unity GameKit Plugin w/ Matchmaking Queue is not working
TLDR; I can't get QueueName to work with matchmaking a turn-based match in Unity using matchmaking rules. Long version: I'm using the apple unity plugin found here: https://github.com/apple/unityplugins/blob/main/plug-ins/Apple.GameKit/Apple.GameKit_Unity/Assets/Apple.GameKit/Documentation~/Apple.GameKit.md I have created a Queue, RuleSet and a simple Rule to match players by following these docs tightly: https://developer.apple.com/documentation/gamekit/finding-players-using-matchmaking-rules. Here is the single rule I have that drives matchmaking: { "data" : { "type" : "gameCenterMatchmakingRules", "id" : "[hiddden-rule-id]", "attributes" : { "referenceName" : "ComplimentaryFactionPreference", "description" : "default desc", "type" : "MATCH", "expression" : "requests[0].properties.preference != requests[1].properties.preference", "weight" : null }, "links" : { "self" : "https://api.appstoreconnect.apple.com/v1/gameCenterMatchmakingRules/[hidden-rule-id]" } }, "links" : { "self" : "https://api.appstoreconnect.apple.com/v1/gameCenterMatchmakingRules" } } which belongs to a rule set which belongs to a queue. I have verified these are setup and linked via the App Store Connect API. Additionally, when I tested queue-based matchmaking without a queue established, I got an error in Unity. Now, with this, I do not. However there is a problem when I attempt to use the queue for matchmaking. I have the basic C# function here: public override void StartSearch(NSMutableDictionary<NSString, NSObject> properties) { if (searching) return; base.StartSearch(properties); //Establish matchmaking requests _matchRequest = GKMatchRequest.Init(); _matchRequest.QueueName = _PreferencesToQueue(GetSerializedPreferences()); _matchRequest.Properties = properties; _matchRequest.MaxPlayers = PLAYERS_COUNT; _matchRequest.MinPlayers = PLAYERS_COUNT; _matchTask = GKTurnBasedMatch.Find(_matchRequest); } The _PreferencesToQueue(GetSerializedPreferences()); returns the exact name of the queue I added my ruleset to. After this function is called, I poll the task generated from the .Find(...) function. Every time I run this function, a new match is created almost instantly. No two players are ever added to the same match. Further, I'm running two built game instances, one on a mac and another on an ipad and when I simultaneously test, I am unable to join games this way. Can someone help me debug why I cannot seem to match make when using a queue based approach?
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Sep ’25
How can I get pixel coordinates in the fragment tile function?
In this video, tile fragment shading is recommended for image processing. In this example, the unpack function takes two arguments, one of which is RasterizerData. As I understand it, this is the data passed to us from the previous stage (Vertex) of the graphics pipeline. However, the properties of MTLTileRenderPipelineDescriptor do not include an option for specifying a Vertex function. Therefore, in this render pass, a mix of commands is used: first, a draw command is executed to obtain UV coordinates, and then threads are dispatched. My question is: without using a draw command, only dispatch, how can I get pixel coordinates in the fragment tile function? For the kernel tile function, everything is clear. typedef struct { float4 OPTexture [[ color(0) ]]; float4 IntermediateTex [[ color(1) ]]; } FragmentIO; fragment FragmentIO Unpack(RasterizerData in [[ stage_in ]], texture2d<float, access::sample> srcImageTexture [[texture(0)]]) { FragmentIO out; //... // Run necessary per-pixel operations out.OPTexture = // assign computed value; out.IntermediateTex = // assign computed value; return out; }
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181
Mar ’25
Black Screen in GPTK – DX 12.1 / Shader Model 6.5 Issue?
Hey everyone, I’m trying to run Kingdom Come: Deliverance 2 using the Game Porting Toolkit, but I’m encountering a black screen when launching the game. From what I know about the game’s requirements, it might be using Shader Model 6.5, which supports advanced features like DirectX Raytracing (DXR) Tier 1.1. This leads me to suspect that the issue could be related to missing support for DirectX 12.1 Features or Shader Model 6.5 in GPTK. Does anyone know if these features are currently supported by GPTK? If not, are there any plans to implement them in future updates? Alternatively, is there any workaround for games that rely on Shader Model 6.5 and ray tracing? Thanks a lot for your help!
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Feb ’25
Game Center save game data to iCloud
We are trying to implement saving and fetching data to and from iCloud, but it have some problems. MacOS: 15.3 Here is what I do: Enable Game Center and iCloud capbility in Signing & Capabilities, pick iCloud Documents, create and select a Container. Sample code: void SaveDataToCloud( const void* buffer, unsigned int datasize, const char* name ) { if(!GKLocalPlayer.localPlayer.authenticated) return; NSData* data = [ NSData dataWithBytes:databuffer length:datasize]; NSString* filename = [ NSString stringWithUTF8String:name ]; [[GKLocalPlayer localPlayer] saveGameData:data withName:filename completionHandler:^(GKSavedGame * _Nullable savedGame, NSError * _Nullable){ if (error != nil) { NSLog( @"SaveDataToCloud error:%@", [ error localizedDescription ] ); } }]; } void FetchCloudSavedGameData() { if ( !GKLocalPlayer.localPlayer.authenticated ) return; [ [ GKLocalPlayer localPlayer ] fetchSavedGamesWithCompletionHandler:^(NSArray<GKSavedGame *> * _Nullable savedGames, NSError * _Nullable error) { if ( error == nil ) { for ( GKSavedGame *item in savedGames ) { [ item loadDataWithCompletionHandler:^(NSData * _Nullable data, NSError * _Nullable error) { if ( error == nil ) { //handle data } else { NSLog( @"FetchCloudSavedGameData failed to load iCloud file: %@, error:%@", item.name, [ error localizedDescription ] ); } } ]; } } else { NSLog( @"FetchCloudSavedGameData error:%@", [ error localizedDescription ] ); } } ]; } Both saveGameData and fetchSavedGamesWithCompletionHandler are not reporting any error, when debugging, saveGameData completionHandler got a nil error, and can get a valid "savedGame", but when try to rebot the game and use "fetchSavedGamesWithCompletionHandler" to fetch data, we got nothing, no error reported, and the savedGames got a 0 length. From this page https://developer.apple.com/forums/thread/718541?answerId=825596022#825596022 we try to wait 30sec after authenticated , then try fetchSavedGamesWithCompletionHandler, still got the same error. Checked: Game Center and iCloud are enabled and login with the same account. iCloud have enough space to save. So what's wrong with it.
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710
Mar ’25
Trouble with MDLMesh.newBox()
I'm trying to build an MDLMesh then add normals let mdlMesh = MDLMesh.newBox(withDimensions: SIMD3<Float>(1, 1, 1), segments: SIMD3<UInt32>(2, 2, 2), geometryType: MDLGeometryType.triangles, inwardNormals:false, allocator: allocator) mdlMesh.addNormals(withAttributeNamed: MDLVertexAttributeNormal, creaseThreshold: 0) When I render the mesh, some normals are (0,0,0). I don't know if the problem is in the mesh, or in the conversion to MTKMesh. Is there a way to examine an MDLMesh with the geometry viewer? When I look at the variable values for my mdlMesh I get this: Not too useful. I don't know how to track down the normals. What's the best way to find out where the normals getting broken?
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150
May ’25
Low Power Mode on MacOS 26 Tahoe + Vsync fullscreen limits application to 30 fps
I'm experiencing a specific issue where when using any of the MacOS 26 Tahoe betas with Low Power Mode enabled and using Vsync in fullscreen, my application framerate gets limited to a hard 30 fps. I have not experienced this on any older OS. For example Low Power Mode on 13.6 Ventura with Vsync fullscreen lets my application run at full 60 fps without issues. Is this a bug or a change in behavior of Low Power Mode on Tahoe? My application is 3D, runs at 60 fps and is sensitive to tearing, so I need Vsync and it is mostly utilized in fullscreen. And Low Power Mode is a default for many Macs, so default experience on Tahoe currently is a halved 30 fps. However there also seems to be inconsistencies of on which machines this happens, but older OSes are always fine.
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Aug ’25