I've been working on Swift game which is not yet launched or available for preview. The game works in such a way that it has idle CPU while the user is thinking and sustained max CPU and GPU on as many cores as possible when he makes a move. Rarely, due to OS activity or something else outside of my control (for example when dropping the OS curtain even if for just a bit then remove it), the game or some of its threads are moved to efficiency cores which results in major stuttering which persists precisely until the game is idle again at which point the game is moved back on performance cores - but if the player keeps making moves the stuttering simply won't go away and so I guess compuptation is locked onto efficiency cores. The issue does not reproduce on MacCatalyst on Intel. How do I tell Swift to avoid efficiency cores? BTW Swift and SceneKIT have AMAZING performance especially when compared to others.

I have a game built in Unreal Engine 5.6 which uses tilt motion controls to rotate an object. I've restricted the app to only run in portrait for iPhone, and everything works fine, however for iPad I've had a few issues relating to multitasking and I can't seem to solve it. Forcing the app to portrait only still allows the app to run in landscape mode, but shows black bars either side of the game, and the axes for the motion controls are incorrect. X becomes Y and Y becomes X, and there's no way for my app to know which orientation it is because the container is still technically portrait. Allowing my game to run in all orientations makes the whole app more presentable, it doesn't add black bars and the game is still functional and I'm able to map the controls correctly because the game knows it's landscape rather than portrait. The problem with allowing my app to run in landscape mode is if multitasking is enabled on the ipad, you can resize the app to be portrait, and then I run into the same problem again where the game thinks it's portrait mode and all of the axes are wrong again. I tried getting the true orientation of the device rather than the scene, but the game is intended to be played flat so instead of returning the orientation of the OS the orientation is FaceUp, which doesn't help. I need to either disable multitasking or find a way of getting the orientation of the OS (not the scene or the device). I haven't found how to get the OS orientation so I've been trying to disable multitasking. I've got Requires Fullscreen true and UIApplicationSupportsMultipleScreens false in my info.plist but my iPad still seems to allow the window to be resized in landscape view. Opening the IOS workspace of my project Requires Fullscreen is ticked but under that it says "Supports Multiple Windows" and the arrow button next to it takes my to my info.plist values, but no indication of how I can change it. I'm using Unreal Engine 5.6 and Xcode 16.0. Xcode is old I know, but this version of unreal engine doesn't seem to support any newer.

I have two devices (iPod, iPhone), each using a different Apple ID. I have an existing game to which I'm adding TBM. When the iPod invites the iPhone, it sends an iMessage invite to the iPhone; when I click on that message, I get "Retrieving", then Game Center in Settings is opened, not my App (same version installed on both devices). I start my App on the iPhone and that match is not shown in the Matchmaker View Controller. When I send an invite from the iPhone to the iPod and I click on the iMessage invite, the app starts but the match isn't listed in the MatchMaker ViewController on the iPod (but is on the iPhone). In addition, when I click on the info circle on the iPhone, it who's the two players and "App Store" under the Game Center name. However, When I do the same on the iPod, it has a "Play your turn" there. Any ideas?

I implemented an EntityAction to change the baseColor tint - and had it working on VisionOS 2.x. import RealityKit import UIKit typealias Float4 = SIMD4<Float> extension UIColor { var float4: Float4 { if cgColor.numberOfComponents == 4, let c = cgColor.components { Float4(Float(c[0]), Float(c[1]), Float(c[2]), Float(c[3])) } else { Float4() } } } struct ColourAction: EntityAction { // MARK: - PUBLIC PROPERTIES let startColour: Float4 let targetColour: Float4 // MARK: - PUBLIC COMPUTED PROPERTIES var animatedValueType: (any AnimatableData.Type)? { Float4.self } // MARK: - INITIATION init(startColour: UIColor, targetColour: UIColor) { self.startColour = startColour.float4 self.targetColour = targetColour.float4 } // MARK: - PUBLIC STATIC FUNCTIONS @MainActor static func registerEntityAction() { ColourAction.subscribe(to: .updated) { event in guard let animationState = event.animationState else { return } let interpolatedColour = event.action.startColour.mixedWith(event.action.targetColour, by: Float(animationState.normalizedTime)) animationState.storeAnimatedValue(interpolatedColour) } } } extension Entity { // MARK: - PUBLIC FUNCTIONS func changeColourTo(_ targetColour: UIColor, duration: Double) { guard let modelComponent = components[ModelComponent.self], let material = modelComponent.materials.first as? PhysicallyBasedMaterial else { return } let colourAction = ColourAction(startColour: material.baseColor.tint, targetColour: targetColour) if let colourAnimation = try? AnimationResource.makeActionAnimation(for: colourAction, duration: duration, bindTarget: .material(0).baseColorTint) { playAnimation(colourAnimation) } } } This doesn't work in VisionOS 26. My current fix is to directly set the material base colour - but this feels like the wrong approach: @MainActor static func registerEntityAction() { ColourAction.subscribe(to: .updated) { event in guard let animationState = event.animationState, let entity = event.targetEntity, let modelComponent = entity.components[ModelComponent.self], var material = modelComponent.materials.first as? PhysicallyBasedMaterial else { return } let interpolatedColour = event.action.startColour.mixedWith(event.action.targetColour, by: Float(animationState.normalizedTime)) material.baseColor.tint = UIColor(interpolatedColour) entity.components[ModelComponent.self]?.materials[0] = material animationState.storeAnimatedValue(interpolatedColour) } } So before I raise this as a bug, was I doing anything wrong in the former version and got lucky? Is there a better approach?

Problem Summary After upgrading to iOS 26.1 and 26.2, I'm experiencing a particle positioning bug in RealityKit where ParticleEmitterComponent particles render at an incorrect offset relative to their parent entity. This behavior does not occur on iOS 18.6.2 or earlier versions, suggesting a regression introduced in the newer OS builds. Environment Details Operating System: iOS 26.1 & iOS 26.2 Framework: RealityKit Xcode Version: 16.2 (16C5032a) Expected vs. Actual Behavior Expected: Particles should render at the position of the entity to which the ParticleEmitterComponent is attached, matching the behavior on iOS 18.6.2 and earlier. Actual: Particles appear away from their parent entity, creating a visual misalignment that breaks the intended AR experience. Steps to Reproduce Create or open an AR application with RealityKit that uses particle components Attach a ParticleEmitterComponent to an entity via a custom system Run the application on iOS 26.1 or iOS 26.2 Observe that particles render at an offset position away from the entity Minimal Code Example Here's the setup from my test case: Custom Component & System: struct SparkleComponent4: Component {} class SparkleSystem4: System { static let query = EntityQuery(where: .has(SparkleComponent4.self)) required init(scene: Scene) {} func update(context: SceneUpdateContext) { for entity in context.scene.performQuery(Self.query) { // Only add once if entity.components.has(ParticleEmitterComponent.self) { continue } var newEmitter = ParticleEmitterComponent() newEmitter.mainEmitter.color = .constant(.single(.red)) entity.components.set(newEmitter) } } } AR Setup: let material = SimpleMaterial(color: .gray, roughness: 0.15, isMetallic: true) let model = Entity() model.components.set(ModelComponent(mesh: boxMesh, materials: [material])) model.components.set(SparkleComponent4()) model.position = [0, 0.05, 0] model.name = "MyCube" let anchor = AnchorEntity(.plane(.horizontal, classification: .any, minimumBounds: [0.2, 0.2])) anchor.addChild(model) arView.scene.addAnchor(anchor) Questions for the Community Has anyone else encountered this particle positioning issue after updating to iOS 26.1/26.2? Are there known workarounds or configuration changes to ParticleEmitterComponent that restore correct positioning? Is this a confirmed bug, or could there be a change in coordinate system handling or transform inheritance that I'm missing? Additional Information I've already submitted this issue via Feedback Assistant(FB21346746)

Since macOS 15.3.2, we have observed that when another window is moved near the App Store's install button, the button disappears. We have attached a related video in the Feedback submission here https://feedbackassistant.apple.com/feedback/20444423 Our application overlays a transparent, watermark-window on top of the system window, which causes the install button in the App Store to be hidden when a user attempts to install an application.Could you advise on how to avoid this issue?

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; }

RealityKit spatial audio crackles and pops on iOS 26.0 beta 5. It works correctly on iOS 18.6 and visionOS 26.0 beta 5. The APIs used are AudioPlaybackController, Entity.prepareAudio, Entity.play Videos of the expected and observed behavior are attached to the feedback FB19423059. The audio should be a consistent, repeating sound, but it seems oddly abbreviated and the volume varies unexpectedly. Thank you for investigating this issue.

In the process of using ARKit's image tracking, we found that different images have significant differences in recognizability. How can we judge the quality of this image in ARKit's image tracking for this situation?

Hi, I have an Unity game. I need to have multiple App Icons for my game for it to be able to be recognized in different countries. In other words, is it possible to have an iOS app in which the App Icon changes based on device locale/language? On Android this is possible using Unity Localization package "com.unity.localization"

My IOS app generates pdf files. Every time my users open the generated pdf files, the autofill popup jumps out, but my pdf file is NOT for interacting. I'm here to ask if there's a way to mark my pdf files as "not a form", like in metadata or anywhere else?

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？

I've tried out a ParticleEmitter in Reality Composer Pro to produce a burst of particles that don't move (i.e. speed close to zero). When viewing from different angles, it clearly looks like the particles are rendered exactly in the wrong order, that is, front first and back last. In other words, back particles obscure front particles. I would prefer it the correct way around. I've only tried this interactively in Reality Composer Pro, not programmatically, but I assume I would get the same result. My Reality Composer Pro "File" (zipped): https://gert-rieger-edv.de/Posts/Post-1/RealityParticles.zip Screenshot: Click on the ParticleEmitter object, then on its Play button, then select the Particles tab and click on "Burst" a few times to get a few random particles. Mac Studio 2025 Apple M4 Max macOS 15.7.2 (24G325) Reality Composer Pro Version 2.0 (494.60.2)

I am trying to create a simple portal like that in RealityKit, but using metal instead of RealityKit. Has anyone been able to create a window or portal like thing to show a skybox outside in mixed Reality?

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

I'm trying to use MTLBinaryArchive. I collected a BinaryArchive from one device and used metal-tt to translate it for all supported iPhone devices, ranging from iPhone 7 Plus to iPhone 16. However, this BinaryArchive is quite large, around 1.5GB uncompressed, and about 500MB compressed in the IPA. I'm wondering how to address the size issue. I watched the WWDC 2022 video, which mentioned that the operating system or app installation process would handle compatibility. Does this compatibility support different GPU chips? I tried installing an IPA with a BinaryArchive collected only from an iPhone 12 on an iPhone 13, but the BinaryArchive didn't take effect. I also saw that Apple supports App Thinning. However, it seems that resources in the Asset Catalog cannot be accessed via URL, and creating an MTLBinaryArchive requires a URL. Is it possible for MTLBinaryArchive to be distributed through App Thinning? The WWDC 2022 video also mentioned using the -Os optimization flag to reduce size. Can this give an estimate of how much compression it would achieve? Are there any methods to solve the BinaryArchive size issue without impacting performance?

I have an odd bug, if I use initWithFrame as the init routine for NSView subclass that uses layers I don't see this bug. But if I embedded this view into a storyboard with a .nib file and use initWithCoder, I need to return true on (BOOL) contentsAreFlipped From the NSView subclass If I don't the CALayer actually renders from 0,0 from the view upwards and off the window. The frame sizes for the NSView and the CALayer are good.. when I see them in updateLayer. Obviously I have a fix.. but I would like to understand why.

Create the QRCode CIFilter<CIBlendWithMask> *f = CIFilter.QRCodeGenerator; f.message = [@"Message" dataUsingEncoding:NSASCIIStringEncoding]; f.correctionLevel = @"Q"; // increase level CIImage *qrcode = f.outputImage; Overlay the icon CIImage *icon = [CIImage imageWithURL:url]; CGAffineTransform *t = CGAffineTransformMakeTranslation( (qrcode.extent.width-icon.extent.width)/2.0, (qrcode.extent.height-icon.extent.height)/2.0); icon = [icon imageByApplyingTransform:t]; qrcode = [icon imageByCompositingOver:qrcode]; Round off the corners static dispatch_once_t onceToken; static CIWarpKernel *k; dispatch_once(&onceToken, ^ { k = [CIWarpKernel kernelWithFunctionName:name fromMetalLibraryData:metalLibData() error:nil]; }); CGRect iExtent = image.extent; qrcode = [k applyWithExtent:qrcode.extent roiCallback:^CGRect(int i, CGRect r) { return CGRectInset(r, -radius, -radius); } inputImage:qrcode arguments:@[[CIVector vectorWithCGRect:qrcode.extent], @(radius)]]; …and this code for the kernel should go in a separate .ci.metal source file: float2 bend_corners (float4 extent, float s, destination dest) { float2 p, dc = dest.coord(); float ratio = 1.0; // Round lower left corner p = float2(extent.x+s,extent.y+s); if (dc.x < p.x && dc.y < p.y) { float2 d = abs(dc - p); ratio = min(d.x,d.y)/max(d.x,d.y); ratio = sqrt(1.0 + ratio*ratio); return (dc - p)*ratio + p; } // Round lower right corner p = float2(extent.x+extent.z-s, extent.y+s); if (dc.x > p.x && dc.y < p.y) { float2 d = abs(dc - p); ratio = min(d.x,d.y)/max(d.x,d.y); ratio = sqrt(1.0 + ratio*ratio); return (dc - p)*ratio + p; } // Round upper left corner p = float2(extent.x+s,extent.y+extent.w-s); if (dc.x < p.x && dc.y > p.y) { float2 d = abs(dc - p); ratio = min(d.x,d.y)/max(d.x,d.y); ratio = sqrt(1.0 + ratio*ratio); return (dc - p)*ratio + p; } // Round upper right corner p = float2(extent.x+extent.z-s, extent.y+extent.w-s); if (dc.x > p.x && dc.y > p.y) { float2 d = abs(dc - p); ratio = min(d.x,d.y)/max(d.x,d.y); ratio = sqrt(1.0 + ratio*ratio); return (dc - p)*ratio + p; } return dc; }

Hi I've noticed one issue in Metal HUD, but I'm not sure if it is a bug in the Metal HUD or if there is a purpose for this behavior. Metal HUD has an option to send the data to system log in raw format where the numbers are like metal-HUD: ,,,,,..., https://developer.apple.com/documentation/xcode/monitoring-your-metal-apps-graphics-performance/ If the HUD is displayed, it works just fine, but it seems that when the HUD is hidden (with shift-F9), it still send the data to system log, but the numbers are the same all the time and are not updated while is still being updated. I would expect that it should log the data no matter if the HUD is displayed or not, this of course leads to incorrect FPS calculations Here is an example of the system log entries when the HUD is not visible:

We have a macOS app (not yet released, but in use by ourselves), that provides scoreboards for streaming sport events. Today it is expected, that there are nice animations for goals, etc. We are streaming using NDI, which requires a CVPixelBuffer for each frame. We currently create these animations using CABasicAnimation, CAAnimation and CAKeyframeAnimation. In addition we use ScreenCaptureKit to generate the frames. This works fine with 25/30 fps, as long as the window where our animations are performed in is visible. But this is not what it should be. We have a smaller window as main app window and control display performing the animations in reduced size, while the streaming animations need to be in HD format and later maybe in 4K. When using an offscreen window, the animations are not calculated. We get 1 frame per second or so. So we actually have to connect an external display to the MacBook and open the large windows there. Ugly solution. Do we use a completely wrong approach? Or is there a way to tell the macOS to perform the animations although it is an offscreen window? If it cannot work that way, what is an alternative?