I'm looking to create an effect on iOS that tracks the user's face position with ARKit and shifts nearer/more prominent geometry in the scene around while more "distant" geometry stays fixed to the XY plane - making it look like the geometry on screen "sticks out" I've managed to implement most of this successfully, but it's not perfect when using PerspectiveCameraComponent in RealityKit because as I shift the camera (and change its field of view based on the user's distance) the backplane changes its orientation (it's always orthogonal to camera's direction). I've tried adopting ProjectiveTransformCameraComponent instead. The idea is that the camera shifts around the scene, mirroring the user's head's position, looking at (0,0,0) and the back plane is adjusted to be parallel with the X,Y plane (animation replicated in Blender below). However, I can't manage to set up ProjectiveTransformCameraComponent with an appropriate matrix or update its transform property in a RealityKit System correctly. I also tried setting many simpler projection matrices as described in a number of guides on camera projection matrices on the internet and all I get is a blank view. Does anyone have some guidance on what the projection matrix that ProjectiveTransformCameraComponent expects is meant to look like or how I would go about accomplishing my goal?

Hi, I can't see RealityKit statistics on Xcode Canvas using: arView.debugOptions = [.showStatistics] The statistics only show on a physical device, not Xcode live canvas with #Preview. Testing in Xcode 26.0.1 (17A400) on Tahoe 26.0.1 (25A362). Use case: I'm using RealityKit as a non-AR 3D engine. Xcode Canvas is useful for live iterations. Is this expected behavior? How can I see FPS on Xcode canvas? SKView for example shows all debug options on both Xcode Canvas and physical devices.

Hello! I have a question about how thread groups work with tile shading. When running "traditional" compute, I get to choose both thread group size and the grid size. However, when using tile shading kernel I only have dispatchThreadsPerTile method - this controls how many threads will be ran in each tile. So far so good, but what about thread groups? The examples in video "Tile Shading on A11" seem to suggest that there will be only one thread group per tile. In the video, [[thread_index_in_threadgroup]] is called "local_id" and it is used to access the image block. I assume this is the default configuration. So when one does the following: Creates MTLRenderPassDescriptor with tileWidth set to W and tileHeight set to H Fires up the tile shading kernel using dispatchThreadsPerTile with MTLSize size = { W, H, 1 } I understand that the result is 1-to-1 mapping between the tile "pixels" and kernel threads. Now, what I would like to do is to have more than one thread group there. I want this for performance reasons: I have a certain compute kernel which I know executes very well with small thread group size. In fact, { 32, 1, 1 } seems to be the fastest. My understanding is that even if I set tile size to 16x16, and so I am executing 256 threads there, there will only be one SIMD group active in a thread group. Meaning that this SIMD group has to execute 8 times over the tile. Is it possible somehow? Or perhaps the limitations of the API are pointing at the limitations of hardware itself, and if I want to execute with SIMD group sized thread groups I have to use "traditional" compute encoder? Will be grateful for help. Michał

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; }

I have run into an issue where I am trying to use atomic_float in a swift package but I cannot get things to compile because it appears that the Swift Package Manager doesn't support Metal 3 (atomic_float is Metal 3 functionality). Is there any way around this? I am using // swift-tools-version: 6.1 and my Metal code includes: #include <metal_stdlib> #include <metal_geometric> #include <metal_math> #include <metal_atomic> using namespace metal; kernel void test(device atomic_float* imageBuffer [[buffer(1)]], uint id [[ thread_position_in_grid ]]) { } But I get an error on the definition of atomic_float . Any help, one more importantly, where I could have found this information about this limitation, would be helpful. -RadBobby

Hi! Using ARView in UIKit or through a UIViewRepresentable in SwiftUI, we can do: arView.debugOptions = [.showPhysics, .showStatistics] What is the equivalent in RealityView?

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'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?

App Storeにある『浮遊時計 Premium』は1Hzごとか10Hzごと、または3段階以上のリフレッシュレート計測はできますか？

The code is pretty simple kernel void naive( constant RunParams *param [[ buffer(0) ]], const device float *A [[ buffer(1) ]], // [N, K] device float *output [[ buffer(2) ]], uint2 gid [[ thread_position_in_grid ]]) { uint a_ptr = gid.x * param->K; for (uint i = 0; i < param->K; i++, a_ptr++) { val += A[b_ptr]; } output[ptr] = val; } when uint a_ptr = gid.x * param->K, the code got 150 GFLops when uint a_ptr = gid.y * param->K, the code got 860 GFLops param->K = 256; thread per group: [16, 16] I'd like to understand why the performance is so different, and how can I profile/diagnose this to help with further optimization.

Given a graph with added obstacles I want to make a copy of it. When I make the copy: currentGrath added 20 obstacles. var newGrapth = currentGrath.copy() as? GKObstacleGraph newGrapth2.removeObstacles([newGrapth!.obstacles.first!]) This returns a BAD ACCESS. I don't understand what's going on or what the problem is. If I do this same thing with the main network there is no problem: currentGrath.removeObstacles([currentGrath!.obstacles.first!]) Thanks for the help

When running on my iPhone SE3 under IOS 18.4.1, achievement banners show as expected. The same code running on my iPad Air2 under IOS 15.8.4, achievement banners do not show, but they are accepted (as shown in the GameCenterViewController). The banners also don't show when running the simulator under iPhone 16 Pro Max under IOS 18.2 or simulator under iPhone SE3 under IOS 18.3. I haven't tried others. [Note that I clear the achievements each run during test so that I can duplicate this]

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.

Hello, I am currently working on a research project under ENINCA Consulting, focused on advanced diagnostic tools for pseudorandom number generators (structural metrics, multi-seed stability, cross-architecture reproducibility, and complementary indicators to TestU01). To validate this diagnostic framework, I prototyped a small non-linear 64-bit PRNG (not as a goal in itself, but simply as a vehicle to test the methodology). During these evaluations, I observed something interesting on Apple Silicon (Mac M1): • bit-exact reproducibility between M1 ARM CPU and M1 Metal GPU, • full BigCrush pass on both CPU and Metal backends, • excellent p-values, • stable behaviour across multiple seeds and runs. This was not the intended objective, the goal was mainly to validate the diagnostic concepts, but these results raised some questions about deterministic compute behaviour in Metal. My question: Is there any official guidance on achieving (or expecting) deterministic RNG or compute behaviour across CPU ↔ Metal GPU on Apple Silicon? More specifically: • Are deterministic compute kernels expected or guaranteed on Metal for scientific workloads? • Are there recommended patterns or best practices to ensure reproducibility across GPU generations (M1 → M2 → M3 → M4)? • Are there known Metal features that can introduce non-determinism? I am not sharing the internal recurrence (this work is proprietary), but I can discuss the high-level diagnostic observations if helpful. Thank you for any insight, very interested in how the Metal engineering team views deterministic compute patterns on Apple Silicon. Pascal ENINCA Consulting

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"

So, I'm done with GPTK and decided to delete it. The only thing I installed was brew -v install apple/apple/game-porting-toolkit and the external libraries from the ditto command. Now, I tried to remove it, but even after brew remove game-porting-toolkit brew autoremove all of the dependencies installed with brew are still there. The most obvious was game-porting-toolkit-compiler, but even after removing this there are so many libraries that are now orphaned and it's just impossible to manually identify those. Is there a way or is the easiest way to simply uninstall Homebrew completely and reinstall it again?

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'm using RealityView in my iOS game mxied with SwiftUI. For the following 2 example usages, the simulator will only render the first RealityView, and the second one is either super laggy or show a black model. Running on the real device is all good, just simualtor has this issue. Have a TabView and each tab has a RealityView. Have a root view and detail view connected via a push navigation, both root and detail have a RealityView. In the Simulator, the second RealityView is going to be very choppy and basically unusable, but on a real iPhone everything looks great. Is this a known simulator issue or I did something bad?

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?

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!