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!

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!

I have something like this drawing in an MTKView (see at bottom). I am finding it difficult to figure out when can the Swift-land resources used in making the MTLBuffer(s) be released? Below, for example, is it ok if args goes out of scope (or is otherwise deallocated) at point 1, 2, or 3? Or perhaps even earlier, as soon as argsBuffer has been created? I have been reading through various articles such as Setting resource storage modes Choosing a resource storage mode for Apple GPUs Copying data to a private resource but it's a lot to absorb and I haven't been really able to find an authoritative description of the required lifetime of the resources in CPU land. I should mention that this is Metal 4 code. In previous versions of Metal, the MTLCommandBuffer had the ability to add a completion handler to be called by the GPU after it has finished running the commands in the buffer but in Metal 4 there is no such thing (it it were even needed for the purpose I am interested in). Any advice and/or pointers to the definitive literature will be appreciated. guard let argsBuffer = device.makeBuffer(bytes: &args,... argumentTable.setAddress(argsBuffer.gpuAddress, ... encoder.setArgumentTable(argumentTable, stages: .vertex) // encode drawing renderEncoder.draw... ... encoder.endEncoding() // 1 commandBuffer.endCommandBuffer() // 2 commandQueue.waitForDrawable(drawable) commandQueue.commit([commandBuffer]) // 3 commandQueue.signalDrawable(drawable) drawable.present()

Hi all, I have been trying to get Apple's assistive touch's snap to item to work for a unity game built using Apple's Core & Accessibility API. The switch control recognises these buttons however, eye tracking will not snap to them. The case in which it needs to snap is when an external eye tracking device is connected and utilises assistive touch & assistive touch's snap to item. All buttons in the game have a AccessibilityNode with the trait 'Button' on them & an appropriate label, which, following the documentation and comments on the developer forum, should allow them to be recognised by snap to item. This is not the case, devices (iPads and iPhones) do not recognise the buttons as a snap to target. Does anyone know why this is the case, and if this is a bug?

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?

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.

What is the recommended way to attach SwiftUI views to RealityKit entities on macOS, iOS, etc? All the APIs seem to be visionOS only: https://developer.apple.com/documentation/realitykit/realityviewattachments https://developer.apple.com/documentation/realitykit/viewattachmentcomponent https://developer.apple.com/documentation/realitykit/presentationcomponent https://developer.apple.com/documentation/realitykit/imagepresentationcomponent My only idea is to do it "manually" with a ZStack and RealityView somehow? I submitted this as a feedback since it seemed like an oversight: FB18034856.

How can one match the walls and floor of a given CapturedRoom ? The transform.eulerAngles of a floor z & y are always 0 ! And the polygons seems to have a different orientation than the walls. So how to figure out the rotation and match the one from the walls ?

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

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？

iPhone(14 Pro Max)で端末の画面にリフレッシュレートを表示させたいのですが、どなたか方法をご存知ないでしょうか？

I've recently run into an issue in Xcode where the sks editor's preview canvas just vanishes for every project on my computer. I don't think it is an issue with my sks files because this works as expected on another computer with the same files, and when it happens it happens for ALL sks files in all projects. There used to be menu items to toggle the canvas and its settings, but those are now gone for me in sks files (they show up for swift files that have previews, however). Any idea what is going on here? How do I get the canvas back? I literally cannot get any work done on my primary computer because of this...

The following minimal snippet SEGFAULTS with SDK 26.0 and 26.1. Won't crash if I remove async from the enclosing function signature - but it's impractical in a real project. import Metal import MetalPerformanceShaders let SEED = UInt64(0x0) typealias T = Float16 /* Why ran in async context? Because global GPU object, and async makeMTLFunction, and async makeMTLComputePipelineState. Nevertheless, can trigger the bug without using global @MainActor let myGPU = MyGPU() */ @main struct CMDLine { static func main() async { let ptr = UnsafeMutablePointer<T>.allocate(capacity: 0) async let future: Void = randomFillOnGPU(ptr, count: 0) print("Main thread is playing around") await future print("Successfully reached the end.") } static func randomFillOnGPU(_ buf: UnsafeMutablePointer<T>, count destbufcount: Int) async { // let (device, queue) = await (myGPU.device, myGPU.commandqueue) let myGPU = MyGPU() let (device, queue) = (myGPU.device, myGPU.commandqueue) // Init MTLBuffer, async let makeFunction, makeComputePipelineState, etc. let tempDataType = MPSDataType.uInt32 let randfiller = MPSMatrixRandomMTGP32(device: device, destinationDataType: tempDataType, seed: Int(bitPattern:UInt(SEED))) print("randomFillOnGPU: successfully created MPSMatrixRandom.") // try await computePipelineState // ^ Crashes before this could return // Or in this minimal case, after randomFillOnGPU() returns // make encoder, set pso, dispatch, commit... } } actor MyGPU { let device : MTLDevice let commandqueue : MTLCommandQueue init() { guard let dev: MTLDevice = MPSGetPreferredDevice(.skipRemovable), let cq = dev.makeCommandQueue(), dev.supportsFamily(.apple6) || dev.supportsFamily(.mac2) else { print("Unable to get Metal Device! Exiting"); exit(EX_UNAVAILABLE) } print("Selected device: \(String(format: "%llX", dev.registryID))") self.device = dev self.commandqueue = cq print("myGPU: initialization complete.") } } See FB20916929. Apparently objc autorelease pool is releasing the wrong address during context switch (across suspension points). I wonder why such obvious case has not been caught before.

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

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!

My app is live but the leaderboards still aren’t updating. App was built with unreal engine 5 with blueprints. I have the leaderboard stat info entered into the node for write integer to leaderboard and a node for show platform specific leaderboard. The leaderboards are shown as live on app connect. When I run the app, the Game Center login functions and the leaderboard interface launches as expected but it just lists a group of friends to invite. There are no scores listed and it says number of players 0 even though I have scored on two different devices and accounts. I have the Game Center entitlement added in Xcode. Not sure where else to look.

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?

I recently needed to develop an application to obtain the window list, which requires Screen Recording permissions. Apple's official documentation mentions using the two functions CGPreflightScreenCaptureAccess and CGRequestScreenCaptureAccess to request permissions. These functions are stated to be available since version 10.15. However, when I used these two functions on a device running macOS 10.15.7, I encountered the errors shown in the attached screenshot. I used the nm tool to inspect the symbols in the CoreGraphics.framework and found that these two functions were not present. Could you help me understand why this is happening?

My app has a number of heterogeneous GPU workloads that all run concurrently. Some of these should be executed with the highest priority because the app’s responsiveness depends on them, while others are triggered by file imports and the like which should have a low priority. If this was running on the CPU I’d assign the former User Interactive QoS and the latter Utility QoS. Is there an equivalent to this for GPU work?

In a Unity game, if the assetBundle.Unloadinterface is called very frequently during normal gameplay, it can cause the game application's screen to freeze, although the background music continues to play normally. This issue only occurs on iPhone 16 and iPhone 17 models, with no problems on lower-version phones. How can this problem be resolved?