I've been using Metal compute shaders for lattice quantum chromodynamics simulations and wanted to share the experience in case others are doing scientific computing on Metal. The workload involves SU(2) matrix operations on 4D lattice grids — lots of 2x2 and 3x3 complex matrix multiplies, reductions over lattice sites, and nearest-neighbor stencil operations. The implementation bridges a C++ scientific framework (Grid) to Metal via Objective-C++ .mm files, with MSL kernels compiled into .metallib archives during the build. Things that work well: Shared memory on M-series eliminates the CPU↔GPU copy overhead that dominates in CUDA workflows The .metallib compilation integrates cleanly with autotools builds using xcrun Float4 packing for SU(2) matrices maps naturally to MSL vector types Things I'm still figuring out: Optimal threadgroup sizes for stencil operations on 4D grids Whether to use MTLHeap for gauge field storage or stick with individual buffers Best practices for double precision — some measurements need float64 but Metal's double support varies by hardware The application is measuring chromofield flux distributions between static quarks, ultimately targeting multi-quark systems. Production runs are on MacBook Pro M-series and Mac Studio. Code: https://github.com/ThinkOffApp/multiquark-lattice-qcd

I just got the new iOS 26 beta, and I LOVE the games app, but it show all of my games, even from years back. Is there a way to remove games from your library on the app?

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?

Question: I'm encountering an issue with in-app purchases (IAP) in Unity, specifically for a non-consumable product in the iOS sandbox environment. Below are the details: Environment: Unity Version: 2022.3.55f1 Unity In-App Purchasing Version: v4.12.2 Device: iPhone (15, iOS 18.1.1) Connection: Wi-Fi iOS Settings: In-App Purchases set to “Allowed” initially Problem Behavior: I attempted to purchase a non-consumable item for the first time. The payment is successfully completed by entering the password. I then background the game app and navigate to the iOS Settings to set In-App Purchases to "Don't Allow." After returning to the game and either closing or killing the app, I try to purchase the same non-consumable item again. I checked canMakePayments() through the Apple configuration, and the app correctly detected that I could not make purchases due to the restriction. I then navigate back to Settings and set In-App Purchases to "Allow." Upon returning to the game, I try purchasing the non-consumable item again. A pop-up appears, saying, "You’ve already purchased this. Would you like to get it again for free?" The issue is: Will it deduct money for the second time, and why is the system allowing the user to purchase the same non-consumable item multiple times after purchasing it once? Is this the expected behavior for Unity In-App Purchasing, or is there something I might be missing in handling non-consumable purchases in this scenario? Additional Information: I’ve confirmed that the "In-App Purchases" are set to “Allowed” before attempting the purchase again. I understand that non-consumable products should not be purchased more than once, so I’m unsure why the system is offering to let the user purchase it again. I appreciate any insights into whether this is expected behavior or if I need to adjust how I handle the purchase flow.

I am attempting to load a jpeg image into a vImage_Buffer. I am just trying to get the data in an ARGB format. This code works fine in the Xcode 15 build , but fails with kvImageInvalidParameter error from vImageBuffer_InitWithCGImage in the Xcode 26 build. This code is written in ObjectiveC++. Here is a code fragment: int CDib_ARGB::Load(LPCSTR pFilename) { int rc = 0; if (NULL == m_pRaw_vImage_Buffer) { NSString *pNS_filename = [[NSString alloc]initWithUTF8String:pFilename]; NSImage *pNSImage = [[NSImage alloc] initWithContentsOfFile:pNS_filename]; if (nil == pNSImage) rc = -1; else { int width = pNSImage.size.width; int height = pNSImage.size.height; if (pNSImage.representations) { NSImageRep *imageRep; int jj; width = 0; height = 0; for (jj = 0; jj < pNSImage.representations.count; jj++) { imageRep = pNSImage.representations[jj]; if (imageRep.pixelsWide > width) width = imageRep.pixelsWide; if (imageRep.pixelsHigh > height) height = imageRep.pixelsHigh; } } NSSize imageSize = NSMakeSize(width, height); NSRect imageRect = NSMakeRect(0, 0, width, height); pNSImage.size = imageSize; CGImageRef cgImage = [pNSImage CGImageForProposedRect:&imageRect context:NULL hints:nil]; if (nil == cgImage) rc = -1; else { //Alloc and load vImage_Buffer. vImage_Buffer *pvImage_Buffer = new vImage_Buffer; if (NULL == pvImage_Buffer) rc = -1; else { vImage_CGImageFormat format; format.bitsPerComponent = 8; format.bitsPerPixel = 32; format.colorSpace = nil; format.bitmapInfo = kCGImageAlphaFirst | kCGBitmapByteOrderDefault;//ARGB8888 format.version = 0; format.decode = nil; format.renderingIntent = kCGRenderingIntentDefault; memset(pvImage_Buffer, 0, sizeof(vImage_Buffer)); long status = vImageBuffer_InitWithCGImage(pvImage_Buffer, &format, nil, cgImage, kvImagePrintDiagnosticsToConsole); if (kvImageNoError != status) { //This is where Xcode 26 sends me. delete pvImage_Buffer; rc = -1; } =========================

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];

我们想在游戏类 App 内接入 Game Center。用户可以在游戏内创建多个角色，若用户在游戏内创建了2个角色：角色1、角色2，请问： 当用户将角色1与 Game Center 绑定后，数据将上报至 Game Center。此时玩家想要将角色1与 Game Center 解除绑定，解绑后，再将角色2与 Game Center 绑定。那么这时角色1的数据是留存在 Game Center 中，还是将被移除？

Hi everyone, I’m currently learning about ParticleEmitterComponentParticleEmitterComponent and exploring the sample app provided in the Simulating particles in your visionOS app documentation. In the sample app, when I set the EmitterPreset to fireworks from the settings panel on the left side of the window and choose SystemImage, I noticed two issues: The image applied to mainEmitter appears clipped or cropped. The image on spawnedEmitter does not update to the selected SystemImage. What I want to achieve: Apply the same SystemImage to both mainEmittermainEmitter and spawnedEmitterspawnedEmitter so that it displays correctly without clipping. Remove the animation that changes the size of spawnedEmitterspawnedEmitter over time and keep it at a constant size. Could someone explain which properties should be adjusted to achieve this behavior? Any guidance or examples would be greatly appreciated. Thanks in advance!

I am just starting to learn SpriteKit and I'm having trouble selecting a scene to preview an action in the actions editor. I created a new macOS Game project (Language: Swift, Game Technology: SpriteKit). When I open the generated 'Actions.sks' file, I see the message "No Preview Scene Selected" in the editor. I see the 'GameScene.sks' scene listed in the "Select..." control in the lower right, but it is greyed out. I'm not able to figure out how to select a scene to preview the action. I'm running Xcode 26.2 on macOS 15. Thanks very much for the help.

When testing my development build for gamecenter authentication, the game crashes. I've breadcrumbed it to the "await GKLocalPlayer.Authenticate();" call. Can't find any documentation on this issue and have been looking through the forums! I've already done all of the usual stuff like verifying bundle identifiers match, ensuring game center is enabled for the app, setting up app store connect, using a sandbox account, etc... Please point me to some resources if you know any. Any help is appreciated, I'm starting to lose hope here!

Hi, I’m stuck with submitting a Game Center leaderboard and wanted to ask if others are seeing the same issue. My setup: App is already live on the App Store Game Center capability is enabled Leaderboard works perfectly in TestFlight (scores are submitted and visible) Problem: When I try to submit the leaderboard for review, I get: “A Game Center enabled app version must be added for review.” This is confusing because: The app already includes Game Center The app is already approved and published Apple documentation says Game Center components can be submitted without a new app version I also tried recreating the leaderboard and checking all settings, but the issue persists. Is this a known App Store Connect issue? Or is there something I’m missing? Thanks!

Hello, MacOS 26 Betas are limiting games (noticeably, games that use java) to the native display of the MacBook Pro (120hz). Even connecting an external display this is not changing. I have submitted a bug report, but I have not had any responses to it yet. I am looking to see if anyone may have an answer or fix to this issue. Thanks!

Why you don’t fix that ?

In the Creating A 3D Application With Hydra Rendering tutorial on the Apple Developer website, on the last step where I execute this command: cmake -S ~/Users/macuser/CreatingA3DApplicationWithHydraRendering/ -B ~/Users/macuser/CreatingA3DApplicationWithHydraRendering/ I keep getting an error: CMake Error at CMakeLists.txt:5 (include): include could not find requested file: /Users/macuser/USDInstall/bin/pxrConfig.cmake I've tried to follow the instructions as mentioned in the README.md file included in the project files at least 5 times as well as moving the pxrConfig.cmake file around and copying it in different folders, then executed the command and was still unsuccessful into generating the proper file expected to compile and render the HydraPlayer renderer. How do I get cmake to generate the Xcode file to create the HydraPlayer renderer?

The sample code just draw a triangle and sample texture. both sample code can draw a correct triangle and sample texture as expected. there are no error message from terminal. Sample code using constexpr Sampler can capture and replay well. Sample code using a argumentTable to bind a MTLSamplerState was crashed when using Metal capture and replay on Xcode. Here are sample codes. Sample Code Test Environment: M1 Pro MacOS 26.3 (25D125) Xcode Version 26.2 (17C52) Feedback ID: FB22031701

Hello, I’m porting my UIKit/SceneKit app to SwiftUI/RealityKit and I’m wondering how to change the camera target programmatically. I created a simple scene in Reality Composer Pro with two spheres. My goal is straightforward: when the user taps a sphere, the camera should look at it as the main target. Following Apple’s videos, I implemented the .gesture modifier and it is printing the tapped sphere correctly, but updating my targetEntity state doesn’t change anything, so the camera won't update its target. Is there a way to access the scene content at that level? Or what else should I do? Here’s my current code implementation: Thanks!

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?

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?

The simplest realityView (content, attachments in ... causes Contextual closure expects 1 argument but 2 were used in closure body. I have checked every example and i cannot understand why i get this error regardless of any content. Note: i have added Attachment(id: "test") to the attachment closure and get Attachment not is scope. imported both realityKit and SwiftUI.

Hi everyone, I'm using the Vision framework’s ImageAestheticsScoresObservation class (https://developer.apple.com/documentation/vision/imageaestheticsscoresobservation). I noticed that the overallScore returned sometimes gives negative values. Could someone confirm whether the expected range of the score is from -1.0 to 1.0? The documentation doesn’t explicitly state the possible score range, so I’d appreciate any clarification or insights. Thanks in advance!