In Instruments, I'm seeing "Zero Time Stamp" events in the "Audio Server" lane. What does that mean?

The document-based SwiftUI example app (https://developer.apple.com/documentation/swiftui/building-a-document-based-app-with-swiftui) doesn't specify a launch image. It would seem per the HIG that the "pinkJungle" background in the app would be a decent candidate for a launch image, since it will be in the background when the document browser comes up. However when specifying it as the UIImageName, it is not aligned the same as the background image. I'm having trouble figuring out how it should be aligned to match the image. The launch image seems to be scaled up a bit over scaledToFill. I suppose a launch storyboard might make this more explicit, but I still should be able to do it without one. This is the image when displayed as the launch image: and this is how it's rendered in the background right before the document browser comes up:

I'm streaming mp3 audio data using URLSession/AudioFileStream/AVAudioConverter and getting occasional silent buffers and glitches (little bleeps and whoops as opposed to clicks). The issues are present in an offline test, so this isn't an issue of underruns. Doing some buffering on the input coming from the URLSession (URLSessionDataTask) reduces the glitches/silent buffers to rather infrequent, but they do still happen occasionally. var bufferedData = Data() func parseBytes(data: Data) { bufferedData.append(data) // XXX: this buffering reduces glitching // to rather infrequent. But why? if bufferedData.count > 32768 { bufferedData.withUnsafeBytes { (bytes: UnsafeRawBufferPointer) in guard let baseAddress = bytes.baseAddress else { return } let result = AudioFileStreamParseBytes(audioStream!, UInt32(bufferedData.count), baseAddress, []) if result != noErr { print("❌ error parsing stream: \(result)") } } bufferedData = Data() } } No errors are returned by AudioFileStream or AVAudioConverter. func handlePackets(data: Data, packetDescriptions: [AudioStreamPacketDescription]) { guard let audioConverter else { return } var maxPacketSize: UInt32 = 0 for packetDescription in packetDescriptions { maxPacketSize = max(maxPacketSize, packetDescription.mDataByteSize) if packetDescription.mDataByteSize == 0 { print("EMPTY PACKET") } if Int(packetDescription.mStartOffset) + Int(packetDescription.mDataByteSize) > data.count { print("❌ Invalid packet: offset \(packetDescription.mStartOffset) + size \(packetDescription.mDataByteSize) > data.count \(data.count)") } } let bufferIn = AVAudioCompressedBuffer(format: inFormat!, packetCapacity: AVAudioPacketCount(packetDescriptions.count), maximumPacketSize: Int(maxPacketSize)) bufferIn.byteLength = UInt32(data.count) for i in 0 ..< Int(packetDescriptions.count) { bufferIn.packetDescriptions![i] = packetDescriptions[i] } bufferIn.packetCount = AVAudioPacketCount(packetDescriptions.count) _ = data.withUnsafeBytes { ptr in memcpy(bufferIn.data, ptr.baseAddress, data.count) } if verbose { print("handlePackets: \(data.count) bytes") } // Setup input provider closure var inputProvided = false let inputBlock: AVAudioConverterInputBlock = { packetCount, statusPtr in if !inputProvided { inputProvided = true statusPtr.pointee = .haveData return bufferIn } else { statusPtr.pointee = .noDataNow return nil } } // Loop until converter runs dry or is done while true { let bufferOut = AVAudioPCMBuffer(pcmFormat: outFormat, frameCapacity: 4096)! bufferOut.frameLength = 0 var error: NSError? let status = audioConverter.convert(to: bufferOut, error: &error, withInputFrom: inputBlock) switch status { case .haveData: if verbose { print("✅ convert returned haveData: \(bufferOut.frameLength) frames") } if bufferOut.frameLength > 0 { if bufferOut.isSilent { print("(haveData) SILENT BUFFER at frame \(totalFrames), pending: \(pendingFrames), inputPackets=\(bufferIn.packetCount), outputFrames=\(bufferOut.frameLength)") } outBuffers.append(bufferOut) totalFrames += Int(bufferOut.frameLength) } case .inputRanDry: if verbose { print("🔁 convert returned inputRanDry: \(bufferOut.frameLength) frames") } if bufferOut.frameLength > 0 { if bufferOut.isSilent { print("(inputRanDry) SILENT BUFFER at frame \(totalFrames), pending: \(pendingFrames), inputPackets=\(bufferIn.packetCount), outputFrames=\(bufferOut.frameLength)") } outBuffers.append(bufferOut) totalFrames += Int(bufferOut.frameLength) } return // wait for next handlePackets case .endOfStream: if verbose { print("✅ convert returned endOfStream") } return case .error: if verbose { print("❌ convert returned error") } if let error = error { print("error converting: \(error.localizedDescription)") } return @unknown default: fatalError() } } }

I'm trying to switch to UIKit's document lifecycle due to serious bugs with SwiftUI's version. However I'm noticing the template project from Xcode isn't compatible with Swift 6 (I already migrated my app to Swift 6.). To reproduce: File -> New -> Project Select "Document App" under iOS Set "Interface: UIKit" In Build Settings, change Swift Language Version to Swift 6 Run app Tap "Create Document" Observe: crash in _dispatch_assert_queue_fail Does anyone know of a work around other than downgrading to Swift 5?

I'm trying to improve my build time on macOS by not building for x86_64. I've got the following settings: This gets Xcode not to build x86_64 for my app, but not all the package dependencies. I've updated most of the packages to swift-tools-version: 6.0 but FlatBuffers is still on 5.8 and .macOS(.v10_14). GPT claims: If your deployment target is set to macOS 10.15 or earlier, Xcode may force x86_64 support for compatibility reasons. But Xcode is building x86_64 for ALL my packages, even the ones that don't depend on FlatBuffers. When I open a package in Xcode that depends on FlatBuffers, then it builds arm only, so that may be a red herring. Not sure what else to try.

In my Swift app, Xcode has decided to put various important settings like, SWIFT_VERSION under "User Defined." Does anyone know why?

I want to turn off my ray-tracing conditionally. There's is_null_acceleration_structure but when I don't bind an acceleration structure (or pass nil to setFragmentAccelerationStructure), I get the following API validation error: -[MTLDebugRenderCommandEncoder validateCommonDrawErrors:]:5782: failed assertion `Draw Errors Validation Fragment Function(vol_deferred_lighting): missing instanceAccelerationStructure binding at index 6 for accelerationStructure[0]. I can turn off API validation and it works, but it seems like I should be able to use nil for the acceleration structure w/o triggering a validation error. Seems like a bug, right? I suppose I can work around this by creating a separate pipeline with the ray-tracing disabled via a function constant instead of using is_null_acceleration_structure. (Can we get a ray-tracing tag for questions?)

I just tried the "Building a document-based app with SwiftUI" sample code for iOS 18. https://developer.apple.com/documentation/swiftui/building-a-document-based-app-with-swiftui I can create a document and then close it. But once I open it back up, I can't navigate back to the documents browser. It also struggles to open documents (I would tap multiple times and nothing happens). This happens on both simulator and device. Will file a bug, but anyone know of a work-around? I can't use a document browser that is this broken.

I've been using an XCFramework of LuaJIT for years now in my app. After upgrading to Xcode 16, calls to the LuaJIT interpreter started segfaulting on macOS in release mode only. Works on iOS (both debug/release). Works fine with Xcode 15.4 (both debug/release). I have a very simple repro. Wondering what could actually cause that sort of thing, given it's the same XCFramework (i.e. precompiled with optimization on). Guessing this is something having to do with the way LuaJIT is called, or the environment in which it runs, when the optimizer is turned on. https://github.com/LuaJIT/LuaJIT/issues/1290 (FB15512926)

I'm wondering if it's possible to do Parallax Occlusion Mapping in RealityKit? Does RK's metal shader API provide enough? I think it would need to be able to discard fragments and thus can't be run as a deferred pass. Not sure though!

"Specifically, your App Description and screenshot references paid features but does not inform users that a purchase is required to access this content." My App Description (Pro 3D art app) doesn't mention that the entire app is a subscription. I didn't think I needed to because Final Cut Pro and Logic Pro don't do that either. Anyone had experience with this? Is there a double-standard or did App Review just make a mistake? Suppose I can add some language at the end of the App Description like "All Features unlocked with subscription"

I'm trying to ray-march an SDF inside a RealityKit surface shader. For the SDF primitive to correctly render with other primitives, the depth of the fragment needs to be set according to the ray-surface intersection point. Is there a way to do that within a RealityKit surface shader? It seems the only values I can set are within surface::surface_properties. If not, can an SDF still be rendered in RealityKit using ray-marching?

In my Metal-based app, I ray-march a 3D texture. I'd like to use RealityKit instead of my own code. I see there is a LowLevelTexture (beta) where I could specify a 3D texture. However on the Metal side, there doesn't seem to be any way to access a 3D texture (realitykit::texture::textures::custom returns a texture2d). Any work-arounds? Could I even do something icky like cast the texture2d to a texture3d in MSL? (is that even possible?) Could I encode the 3d texture into an argument buffer and get that in somehow?

I'm recreating the sleep timer from the Podcasts app. How can I display an icon for the picker instead of the current selection? This doesn't work: Picker("Sleep Timer", systemImage: "moon.zzz.fill", selection: $sleepTimerDuration) { Text("Off").tag(0) Text("5 Minutes").tag(5) Text("10 Minutes").tag(10) Text("15 Minutes").tag(15) Text("30 Minutes").tag(30) Text("45 Minutes").tag(45) Text("1 Hour").tag(60) } Do I need to drop down to UIKit for this?

I'm trying to create a MTLFXTemporalScaler as follows (this is adapted from the sample code): func updateTemporalScaler() { let desc = MTLFXTemporalScalerDescriptor() desc.inputWidth = renderTarget.renderSize.width desc.inputHeight = renderTarget.renderSize.height desc.outputWidth = renderTarget.windowSize.width desc.outputHeight = renderTarget.windowSize.height desc.colorTextureFormat = .bgra8Unorm desc.depthTextureFormat = .depth32Float desc.motionTextureFormat = .rg16Float desc.outputTextureFormat = .bgra8Unorm guard let temporalScaler = desc.makeTemporalScaler(device: device) else { fatalError("The temporal scaler effect is not usable!") } temporalScaler.motionVectorScaleX = Float(renderTarget.renderSize.width) temporalScaler.motionVectorScaleY = Float(renderTarget.renderSize.height) mfxTemporalScaler = temporalScaler } I'm getting the following error the 3rd time the code is called: /AppleInternal/Library/BuildRoots/91a344b1-f985-11ee-b563-fe8bc7981bff/Library/Caches/com.apple.xbs/Sources/MetalPerformanceShadersGraph/mpsgraph/MetalPerformanceShadersGraph/Runtimes/MPSRuntime/Operations/RegionOps/ANRegion.mm:855: failed assertion `ANE intermediate buffer handle not same!' When I copy the code out to a playground, it succeeds when called with the same sequence of descriptors. Does this seem like a bug with MTLFXTemporalScaler?