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MetalFX FrameInterpolator assertion: `Color texture width mismatch from descriptor` even when all texture sizes match
I am integrating MetalFX FrameInterpolator into a custom Unity RenderGraph–based render pipeline (C++ native plugin + C# render passes), and I am hitting the following assertion at runtime: /MetalFXDebugError.h:29: failed assertion `Color texture width mismatch from descriptor' What makes this confusing is that all input/output textures have the correct width and height, and they exactly match the values specified in the MTLFXFrameInterpolatorDescriptor. Setup Input resolution: 1024 x 512 Output resolution: 2048 x 1024 MTLFXTemporalScaler is created first and then passed into MTLFXFrameInterpolator The TemporalScaler and FrameInterpolator descriptors use the same input/output sizes and formats All Metal textures: Have no parentTexture Are 2D textures Match the descriptor sizes exactly (verified via logging) Texture bindings at encode time frameInterpolator.colorTexture = mtlTexColor; // 1024 x 512 frameInterpolator.prevColorTexture = mtlTexPrevColor; // 1024 x 512 frameInterpolator.motionTexture = mtlTexMotion; // 1024 x 512 frameInterpolator.depthTexture = mtlTexDepth; // 1024 x 512 frameInterpolator.uiTexture = mtlTexUI; // 2048 x 1024 frameInterpolator.outputTexture = mtlTexOutput; // 2048 x 1024 All widths/heights are logged and match: Color : 1024 x 512 (input) PrevColor : 1024 x 512 (input) Motion : 1024 x 512 (input) Depth : 1024 x 512 (input) UI : 2048 x 1024 (output) Output : 2048 x 1024 (output) The TemporalScaler works correctly on its own. The assertion only occurs when using FrameInterpolator. Important detail about colorTexture Originally, colorTexture was copied from BuiltinRenderTextureType.CurrentActive. After reading that this might violate MetalFX semantics, I changed the pipeline so that: colorTexture now comes from a dedicated private RenderGraph texture It is not the backbuffer It is not a drawable It is not used as a final output It is created before UI rendering Despite this, the assertion still occurs. Question Can uiTexture for MTLFXFrameInterpolator legally come from a texture copied from BuiltinRenderTextureType.CurrentActive? More generally: Are there additional hidden constraints on colorTexture / prevColorTexture (such as Metal usage, storageMode, aliasing, or hazard tracking) that could cause this assertion, even when sizes match? Does FrameInterpolator require colorTexture and prevColorTexture to be created in a very specific way (e.g. non-aliased, ShaderRead usage, identical Metal resource properties)? Any clarification on the exact semantic requirements for colorTexture, prevColorTexture, or uiTexture in MetalFX FrameInterpolator would be greatly appreciated.
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640
Jan ’26
Background GPU Access availability
I would love to use Background GPU Access to do some video processing in the background. However the documentation of BGContinuedProcessingTaskRequest.Resources.gpu clearly states: Not all devices support background GPU use. For more information, see Performing long-running tasks on iOS and iPadOS. Is there a list available of currently released devices that do (or don't) support GPU background usage? That would help to understand what part of our user base can use this feature. (And what hardware we need to test this on as developers.) For example it seems that it isn't supported on an iPad Pro M1 with the current iOS 26 beta. The simulators also seem to not support the background GPU resource. So would be great to understand what hardware is capable of using this feature!
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1.1k
Jul ’25
SpriteKit scene used as SCNView.overlaySKScene crashes due to SKShapeNode
I recently published my first game on the App Store. It uses SceneKit with a SpriteKit overlay. All crashes Xcode downloaded for it so far are related to some SpriteKit/SceneKit internals. The most common crash is caused by SKCShapeNode::_NEW_copyRenderPathData. What could cause such a crash? crash.crash While developing this game (and the BoardGameKit framework that appears in the crash log) over the years I experienced many crashes presumably caused by the SpriteKit overlay (I opened a post SceneKit app randomly crashes with EXC_BAD_ACCESS in jet_context::set_fragment_texture about such a crash in September 2024), and other people on the internet also mention that they experience crashes when using SpriteKit as a SceneKit overlay. Should I use a separate SKView and lay it on top of SCNView rather than setting SCNView.overlaySKScene? That seemed to solve the crashes for a guy on stackoverflow, but is it also encouraged by Apple? I know SceneKit is deprecated, but according to Apple critical bugs would still be fixed. Could this be considered a critical bug?
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766
Jan ’26
macOS Tahoe Beta 4 disabled __asm keyword for Metal
Hi, developers, I maintain a shipped app that uses string concatenation to construct Metal shader and compile on-device. Beta 4 seems disabled __asm keyword, resulting the compilation failure. The error is: v2/GEMMKernel.cpp:229: error: program_source:23:9: error: illegal string literal in 'asm' __asm("air.simdgroup_async_copy_1d.p3i8.p1i8"); The relevant code is available at https://github.com/liuliu/ccv/blob/unstable/lib/nnc/mfa/v2/GEMMHeaders.cpp#L30 although any __asm will trip this. Please give us guidance on whether this is a regression or this will be something enforced in 26 release. Personally, I would consider this as a bug given it won't impact anything "compiled" shaders. Thanks for your patience reading this!
Topic: Graphics & Games SubTopic: Metal Tags:
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947
Jul ’25
What good is NSBitmapFormatAlphaNonpremultiplied?
If I create a bitmap image and then try to get ready to draw into it, like so: NSBitmapImageRep* newRep = [[NSBitmapImageRep alloc] initWithBitmapDataPlanes: nullptr pixelsWide: 128 pixelsHigh: 128 bitsPerSample: 8 samplesPerPixel: 4 hasAlpha: YES isPlanar: NO colorSpaceName: NSDeviceRGBColorSpace bitmapFormat: NSBitmapFormatAlphaNonpremultiplied | NSBitmapFormatThirtyTwoBitBigEndian bytesPerRow: 4 * 128 bitsPerPixel: 32]; [NSGraphicsContext setCurrentContext: [NSGraphicsContext graphicsContextWithBitmapImageRep: newRep]]; then the log shows this error: CGBitmapContextCreate: unsupported parameter combination: RGB 8 bits/component, integer 512 bytes/row kCGImageAlphaLast kCGImageByteOrderDefault kCGImagePixelFormatPacked Valid parameters for RGB color space model are: 16 bits per pixel, 5 bits per component, kCGImageAlphaNoneSkipFirst 32 bits per pixel, 8 bits per component, kCGImageAlphaNoneSkipFirst 32 bits per pixel, 8 bits per component, kCGImageAlphaNoneSkipLast 32 bits per pixel, 8 bits per component, kCGImageAlphaPremultipliedFirst 32 bits per pixel, 8 bits per component, kCGImageAlphaPremultipliedLast 32 bits per pixel, 10 bits per component, kCGImageAlphaNone|kCGImagePixelFormatRGBCIF10|kCGImageByteOrder16Little 64 bits per pixel, 16 bits per component, kCGImageAlphaPremultipliedLast 64 bits per pixel, 16 bits per component, kCGImageAlphaNoneSkipLast 64 bits per pixel, 16 bits per component, kCGImageAlphaPremultipliedLast|kCGBitmapFloatComponents|kCGImageByteOrder16Little 64 bits per pixel, 16 bits per component, kCGImageAlphaNoneSkipLast|kCGBitmapFloatComponents|kCGImageByteOrder16Little 128 bits per pixel, 32 bits per component, kCGImageAlphaPremultipliedLast|kCGBitmapFloatComponents 128 bits per pixel, 32 bits per component, kCGImageAlphaNoneSkipLast|kCGBitmapFloatComponents See Quartz 2D Programming Guide (available online) for more information. If I don't use NSBitmapFormatAlphaNonpremultiplied as part of the format, I don't get the error message. My question is, why does the constant NSBitmapFormatAlphaNonpremultiplied exist if you can't use it like this? If you're wondering why I wanted to do this: I want to extract the RGBA pixel data from an image, which might have non-premultiplied alpha. And elsewhere online, I saw advice that if you want to look at the pixels of an image, draw it into a bitmap whose format you know and look at those pixels. And I don't want the process of drawing to premultiply my alpha.
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181
Jun ’25
How to use MetalPeformancePrimitives
I am trying to learn the new Metal Peformance Primitives APIs. I have added the MetalPeformancePrimitives framework and included the header in my shader code as per documentation #include <MetalPeformancePrimitives/MetalPeformancePrimitives.h> Unfortunately, Xcode complains that the header cannot be found. How do I include it properly? I am using Xcode 26 on Tahoe. The MetalPeformancePrimitives framework is present on my machine and I can inspect the headers in the filesystem.
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789
Oct ’25
Clarifying when Game Center activity events fire relative to authentication
Hello, In our game we enforce an age gate before showing Game Center sign‑in. Only after the user passes the age gate do we call GKLocalPlayer.localPlayer.authenticateHandler. The reason I’m asking is that we want to reliably detect if the game was launched from a Game Center activity in the Games app (iOS 26+). If the user prefers to enter via activities, we don’t want to miss that event during cold start. Our current proposal is: Register a GKLocalPlayerListener early in didFinishLaunchingWithOptions: so the app is ready to catch events. Queue any incoming events in our dispatcher. Only process those events after the user passes the age gate and authentication succeeds. My questions are: Does player:wantsToPlayGameActivity:completionHandler: ever fire before authentication, or only after the local player is authenticated? If it only fires after authentication, is our “register early but gate processing” approach the correct way to ensure we don’t miss activity launches? Is there any recommended pattern to distinguish “activity launch” vs. “normal launch” in this age‑gate scenario? We want to respect Apple’s age gate requirements, but also ensure activity launches are not lost if the user prefers that entry point. Sorry if this is a stupid question — I just want to be sure we’re following the right pattern. Thanks for any clarification or best‑practice guidance!
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592
Feb ’26
CIBumpDistortion filter not working on my view
I'm trying to apply a CIBumpDistortion Core Image filter to a view that contains a UILabel (my storyLabel). The goal is to create a visual bump/magnifying glass effect over the text. However, despite my attempts, the filter doesn't seem to render at all. The view and the label appear as normal, with no distortion effect. I've tried adjusting the filter parameters and reviewing the view hierarchy, but without success. I also haven't been able to find clear documentation or examples for applying this filter to a UIView's layer. // // TVView.swift // Mistery // // Created by Joje on 31/07/25. // import CoreImage import CoreImage.CIFilterBuiltins import UIKit import AVFoundation final class TVView: UIView { // propriedades animacao texto private var textAnimationTimer: Timer? private var fullTextToAnimate: String = "" private var currentCharIndex: Int = 0 // propriedades video estatica private var player: AVQueuePlayer? private var playerLayer: AVPlayerLayer? private var playerLooper: AVPlayerLooper? var onNextButtonTap: () -> Void = {} // MARK: - Subviews // imagem da TV private(set) lazy var tvImageView: UIImageView = { let imageView = UIImageView() imageView.translatesAutoresizingMaskIntoConstraints = false imageView.image = UIImage(named: "tvFinal") imageView.contentMode = .scaleAspectFit return imageView }() // texto que passa dentro da TV private(set) lazy var storyLabel: UILabel = { let label = UILabel() label.translatesAutoresizingMaskIntoConstraints = false //label.backgroundColor = .gray label.textColor = .red label.font = UIFont(name: "MeltedMonster", size: 30) label.textAlignment = .left label.numberOfLines = 0 label.text = "" return label }() private(set) lazy var nextButton: UIButton = { let button = UIButton(type: .system) button.translatesAutoresizingMaskIntoConstraints = false //button.backgroundColor = .darkGray button.addTarget(self, action: #selector(didPressNextButton), for: .touchUpInside) return button }() // MARK: - Lifecycle override init(frame: CGRect) { super.init(frame: frame) backgroundColor = .black setupVideoPlayer() addSubviews() setupConstraints() } override func layoutSubviews() { super.layoutSubviews() playerLayer?.frame = tvImageView.frame.insetBy(dx: tvImageView.frame.width * 0.05, dy: tvImageView.frame.height * 0.18) setupFisheyeEffect() } private func setupFisheyeEffect() { // cria o filtro guard let filter = CIFilter(name: "CIBumpDistortion") else {return print("erro")} storyLabel.layer.shouldRasterize = true storyLabel.layer.rasterizationScale = UIScreen.main.scale // define os parametros filter.setDefaults() // centro do efeito let center = CIVector(x: storyLabel.bounds.midX, y: storyLabel.bounds.midY) filter.setValue(center, forKey: kCIInputCenterKey) // raio de distorção filter.setValue(storyLabel.bounds.width, forKey: kCIInputRadiusKey) // intensidade de distorção filter.setValue(7, forKey: kCIInputScaleKey) storyLabel.layer.filters = [filter] } required init?(coder: NSCoder) { fatalError("init(coder:) has not been implemented") } // MARK: - Button actions @objc private func didPressNextButton() { onNextButtonTap() } @objc private func animateNextCharacter() { guard currentCharIndex < fullTextToAnimate.count else { textAnimationTimer?.invalidate() return } let currentTextIndex = fullTextToAnimate.index(fullTextToAnimate.startIndex, offsetBy: currentCharIndex) let partialText = String(fullTextToAnimate[...currentTextIndex]) storyLabel.text = partialText currentCharIndex += 1 } public func updateStoryText(with text: String) { textAnimationTimer?.invalidate() storyLabel.text = "" fullTextToAnimate = text currentCharIndex = 0 textAnimationTimer = Timer.scheduledTimer(timeInterval: 0.12, target: self, selector: #selector(animateNextCharacter), userInfo: nil, repeats: true) } // MARK: - Setup methods private func setupVideoPlayer() { guard let videoURL = Bundle.main.url(forResource: "static-video", withExtension: "mov") else { print("Erro: Não foi possível encontrar o arquivo de vídeo static-video.mov") return } let playerItem = AVPlayerItem(url: videoURL) player = AVQueuePlayer(playerItem: playerItem) // LINHA COM POSSIVEL ERRO playerLooper = AVPlayerLooper(player: player!, templateItem: playerItem) playerLayer = AVPlayerLayer(player: player) playerLayer?.videoGravity = .resizeAspectFill if let layer = playerLayer { self.layer.addSublayer(layer) } player?.play() } private func addSubviews() { self.addSubview(storyLabel) self.addSubview(tvImageView) self.addSubview(nextButton) } private func setupConstraints() { NSLayoutConstraint.activate([ // TV Image tvImageView.centerXAnchor.constraint(equalTo: centerXAnchor), tvImageView.centerYAnchor.constraint(equalTo: centerYAnchor), tvImageView.widthAnchor.constraint(equalTo: widthAnchor), // TV Text storyLabel.centerXAnchor.constraint(equalTo: tvImageView.centerXAnchor, constant: -50), storyLabel.centerYAnchor.constraint(equalTo: tvImageView.centerYAnchor, constant: -25), storyLabel.widthAnchor.constraint(equalTo: tvImageView.widthAnchor, multiplier: 0.35), storyLabel.heightAnchor.constraint(equalTo: tvImageView.heightAnchor, multiplier: 0.42), //TV Button nextButton.topAnchor.constraint(equalTo: tvImageView.centerYAnchor, constant: -25), nextButton.centerXAnchor.constraint(equalTo: self.centerXAnchor, constant: 190), nextButton.widthAnchor.constraint(equalToConstant: 100), nextButton.heightAnchor.constraint(equalToConstant: 160) ]) } } #Preview{ ViewController() }
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Sep ’25
How does the automatch feature work in Game Kit?
I'm developing a turn based game. When I present the GKTurnBasedMatchmakerViewController players can opt in for automatch instead of selecting a specific friend as opponent. How exactly does the matching work if a player doesn't specify anything explicitly? Does Game Center send push notifications in a round robin fashion to all friends and the first one to accept is then matched as opponent? Is this documented somewhere?
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518
Jan ’26
RealityView content scale factor
Hi, following the recent deprecation of SceneKit, I'm trying to move a couple of my SceneKit projects to RealityKit. One thing I can't seem to find is how to change the content scale factor when using a RealityView in SwiftUI. It was really easy to do in SceneKit with just a SCNView property, and it seems that it's also possible when using ARView, but I can't find a way to do it with a RealityView. Maybe it's a SwiftUI limitation?
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Jul ’25
Does VisionOS have the equivalent of ARView.physicsOrigin?
I'm trying to scale the physics of a scene without changing the apparent size to avoid the low-speed zeroing-out of motion that the physics simulation does. I found a technique for using separate simulation and physics roots in the docs, but it relies on ARView, which VisionOS doesn't have. This seems more elegant than scaling absolutely everything with shared root -- any chance I'm just failing in my searches to find the equivalent functionality?
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5d
App Freezes on iPadOS 26.x - GPU Metal Errors
I work on a Qt/QML app that uses Esri Maps SDK for Qt and that is deployed to both Windows and iPads. With a recent iPad OS upgrade to 26.1, many iPad users are reporting the application freezing after panning and/or identifying features in the map. It runs fine for our Windows users. I was able to reproduce this and grabbed the following error messages when the freeze happens: IOGPUMetalError: Caused GPU Address Fault Error (0000000b:kIOGPUCommandBufferCallbackErrorPageFault) IOGPUMetalError: Invalid Resource (00000009:kIOGPUCommandBufferCallbackErrorInvalidResource) Environment: Qt 6.5.4 (Qt for iOS) Esri Maps SDK for Qt 200.3 iPadOS 26.1 Because it appears to be a Metal error, I tried using OpenGL (Qt offers a way to easily set hte target graphics api): QQuickWindow::setGraphicsApi(QSGRendererInterface::GraphicsApi::OpenGL) Which worked! No more freezing. But I'm seeing many posts that OpenGL has been deprecated by Apple. I've seen posts that Apple deprecated OpenGL ES. But it seems to still be available with iPadOS 26.1. If so, will this fix (above) just cause problems with a future iPadOS update? Any other suggestions to address this issue? Upgrading our version of Qt + Esri SDK to the latest version is not an option for us. We are in the process to upgrade the full application, but it is a year or two out. So, we just need a fix to buy us some time for now. Appreciate any thoughts/insights....
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565
Dec ’25
GameKit Turn Based Matches Push Notifications
I'm developing a game that supports GameKit turn based matches. What I don't understand is this: Is tapping on the Game Center notification push messages the only way for the GKTurnBasedEventListener to trigger? What if someone misses the push message (swiping it away by accident or something like that) but still wants to join? Is there some inbox somewhere where the pending messages can be seen or fetched? Also it was mentioned in a very old WWDC video (from 2013, I think that's the latest with information about turn based matches) that the notification also includes a badge for the icon. However, I do not understand how to implement that. Is there any documentation for that?
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899
Jan ’26
RealityKit .Kinematic + collisions (visionOs)
Hi everyone, I'm new to visionOS development. I'm trying to create a physics-based scene (with gravity) where users can pick up and move objects on a workbench. I am struggling with physics interactions during the drag gesture: Kinematic Mode: If I switch to .kinematic during the drag, the object moves smoothly but clips through other objects (no collisions). Dynamic Mode: I tried keeping it .dynamic and applying linear velocity toward the hand position, but the movement feels laggy and unresponsive. Hybrid Approach: I tried switching to .kinematic during DragGesture.onChange and back to .dynamic on collision, but this causes the entity to jitter/shake violently when touching other objects. Has anyone found a clean way to drag objects while maintaining solid collisions. Thanks for your help!
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1w
Memory leak when no draw calls issued to encoder
I noticed that when the render command encoder adds no draw calls an apps memory usage seems to grow unboundedly. Using a super simple MTKView-based drawing with the following delegate (code at end). If I add the simplest of draw calls, e.g., a single vertex, the app's memory usage is normal, around 100-ish MBs. I am attaching a couple screenshot, one from Xcode and one from Instruments. What's going on here? Is this an illegal program? If yes, why does it not crash, such as if the encode or command buffer weren't ended. Or is there some race condition at play here due to the lack of draws? class Renderer: NSObject, MTKViewDelegate { var device: MTLDevice var commandQueue: MTL4CommandQueue var commandBuffer: MTL4CommandBuffer var allocator: MTL4CommandAllocator override init() { guard let d = MTLCreateSystemDefaultDevice(), let queue = d.makeMTL4CommandQueue(), let cmdBuffer = d.makeCommandBuffer(), let alloc = d.makeCommandAllocator() else { fatalError("unable to create metal 4 objects") } self.device = d self.commandQueue = queue self.commandBuffer = cmdBuffer self.allocator = alloc super.init() } func mtkView(_ view: MTKView, drawableSizeWillChange size: CGSize) {} func draw(in view: MTKView) { guard let drawable = view.currentDrawable else { return } commandBuffer.beginCommandBuffer(allocator: allocator) guard let descriptor = view.currentMTL4RenderPassDescriptor, let encoder = commandBuffer.makeRenderCommandEncoder( descriptor: descriptor ) else { fatalError("unable to create encoder") } encoder.endEncoding() commandBuffer.endCommandBuffer() commandQueue.waitForDrawable(drawable) commandQueue.commit([commandBuffer]) commandQueue.signalDrawable(drawable) drawable.present() } }
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435
Jan ’26
Request: Allow Game Mode to be enabled locally for non-game App Store categories
Hi Apple team, Game Mode was introduced in iOS 18. To activate Game Mode, an app must include specific key-value pairs in its *.plist and be categorized as a "Game" on the App Store. My app (https://apps.apple.com/us/app/voidlink/id6747717070) works primarily as a self-hosted game streaming (PC->iPhone/iPad) client. Game Mode provides clear benefits in terms of latency and frame rate stability, but it can currently only be activated when running via Xcode or TestFlight. I am an individual iOS developer based in China, where an additional government license is required for apps to be listed under the "Game" category on the App Store. Obtaining such a license is very difficult for independent developers, so my app has been categorized under "Utilities" instead.(If move the app to game category, it will disappear from Chinese App Store immediately) Expectation / Suggestion: Please consider making Game Mode available as a local, user-controllable option on iOS18/26+, such as through a system “App Pool” where users can choose which apps to enable Game Mode for, regardless of App Store category. This would greatly benefit use cases like streaming clients, benchmarking tools, and remote play utilities, without requiring developers to reclassify their apps as “Games” on App Store.
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782
Nov ’25
Moving from SceneKit - fog missing
I am rewriting an unfinished SceneKit project as RealityKit (NonAR). As far as I can see, RealityKit is missing basic fog functionality? Fog was simple & easy to implement in SCeneKit (fogStartDistance / fogEndDistance / fogDensityExponent / fogColor). Are there any plans to implement something like this in RealityKit? Are there any simple workarounds?
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Aug ’25
MetalFX FrameInterpolator assertion: `Color texture width mismatch from descriptor` even when all texture sizes match
I am integrating MetalFX FrameInterpolator into a custom Unity RenderGraph–based render pipeline (C++ native plugin + C# render passes), and I am hitting the following assertion at runtime: /MetalFXDebugError.h:29: failed assertion `Color texture width mismatch from descriptor' What makes this confusing is that all input/output textures have the correct width and height, and they exactly match the values specified in the MTLFXFrameInterpolatorDescriptor. Setup Input resolution: 1024 x 512 Output resolution: 2048 x 1024 MTLFXTemporalScaler is created first and then passed into MTLFXFrameInterpolator The TemporalScaler and FrameInterpolator descriptors use the same input/output sizes and formats All Metal textures: Have no parentTexture Are 2D textures Match the descriptor sizes exactly (verified via logging) Texture bindings at encode time frameInterpolator.colorTexture = mtlTexColor; // 1024 x 512 frameInterpolator.prevColorTexture = mtlTexPrevColor; // 1024 x 512 frameInterpolator.motionTexture = mtlTexMotion; // 1024 x 512 frameInterpolator.depthTexture = mtlTexDepth; // 1024 x 512 frameInterpolator.uiTexture = mtlTexUI; // 2048 x 1024 frameInterpolator.outputTexture = mtlTexOutput; // 2048 x 1024 All widths/heights are logged and match: Color : 1024 x 512 (input) PrevColor : 1024 x 512 (input) Motion : 1024 x 512 (input) Depth : 1024 x 512 (input) UI : 2048 x 1024 (output) Output : 2048 x 1024 (output) The TemporalScaler works correctly on its own. The assertion only occurs when using FrameInterpolator. Important detail about colorTexture Originally, colorTexture was copied from BuiltinRenderTextureType.CurrentActive. After reading that this might violate MetalFX semantics, I changed the pipeline so that: colorTexture now comes from a dedicated private RenderGraph texture It is not the backbuffer It is not a drawable It is not used as a final output It is created before UI rendering Despite this, the assertion still occurs. Question Can uiTexture for MTLFXFrameInterpolator legally come from a texture copied from BuiltinRenderTextureType.CurrentActive? More generally: Are there additional hidden constraints on colorTexture / prevColorTexture (such as Metal usage, storageMode, aliasing, or hazard tracking) that could cause this assertion, even when sizes match? Does FrameInterpolator require colorTexture and prevColorTexture to be created in a very specific way (e.g. non-aliased, ShaderRead usage, identical Metal resource properties)? Any clarification on the exact semantic requirements for colorTexture, prevColorTexture, or uiTexture in MetalFX FrameInterpolator would be greatly appreciated.
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4
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640
Activity
Jan ’26
Background GPU Access availability
I would love to use Background GPU Access to do some video processing in the background. However the documentation of BGContinuedProcessingTaskRequest.Resources.gpu clearly states: Not all devices support background GPU use. For more information, see Performing long-running tasks on iOS and iPadOS. Is there a list available of currently released devices that do (or don't) support GPU background usage? That would help to understand what part of our user base can use this feature. (And what hardware we need to test this on as developers.) For example it seems that it isn't supported on an iPad Pro M1 with the current iOS 26 beta. The simulators also seem to not support the background GPU resource. So would be great to understand what hardware is capable of using this feature!
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4
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1.1k
Activity
Jul ’25
SpriteKit scene used as SCNView.overlaySKScene crashes due to SKShapeNode
I recently published my first game on the App Store. It uses SceneKit with a SpriteKit overlay. All crashes Xcode downloaded for it so far are related to some SpriteKit/SceneKit internals. The most common crash is caused by SKCShapeNode::_NEW_copyRenderPathData. What could cause such a crash? crash.crash While developing this game (and the BoardGameKit framework that appears in the crash log) over the years I experienced many crashes presumably caused by the SpriteKit overlay (I opened a post SceneKit app randomly crashes with EXC_BAD_ACCESS in jet_context::set_fragment_texture about such a crash in September 2024), and other people on the internet also mention that they experience crashes when using SpriteKit as a SceneKit overlay. Should I use a separate SKView and lay it on top of SCNView rather than setting SCNView.overlaySKScene? That seemed to solve the crashes for a guy on stackoverflow, but is it also encouraged by Apple? I know SceneKit is deprecated, but according to Apple critical bugs would still be fixed. Could this be considered a critical bug?
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4
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0
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766
Activity
Jan ’26
macOS Tahoe Beta 4 disabled __asm keyword for Metal
Hi, developers, I maintain a shipped app that uses string concatenation to construct Metal shader and compile on-device. Beta 4 seems disabled __asm keyword, resulting the compilation failure. The error is: v2/GEMMKernel.cpp:229: error: program_source:23:9: error: illegal string literal in 'asm' __asm("air.simdgroup_async_copy_1d.p3i8.p1i8"); The relevant code is available at https://github.com/liuliu/ccv/blob/unstable/lib/nnc/mfa/v2/GEMMHeaders.cpp#L30 although any __asm will trip this. Please give us guidance on whether this is a regression or this will be something enforced in 26 release. Personally, I would consider this as a bug given it won't impact anything "compiled" shaders. Thanks for your patience reading this!
Topic: Graphics & Games SubTopic: Metal Tags:
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4
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6
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947
Activity
Jul ’25
What good is NSBitmapFormatAlphaNonpremultiplied?
If I create a bitmap image and then try to get ready to draw into it, like so: NSBitmapImageRep* newRep = [[NSBitmapImageRep alloc] initWithBitmapDataPlanes: nullptr pixelsWide: 128 pixelsHigh: 128 bitsPerSample: 8 samplesPerPixel: 4 hasAlpha: YES isPlanar: NO colorSpaceName: NSDeviceRGBColorSpace bitmapFormat: NSBitmapFormatAlphaNonpremultiplied | NSBitmapFormatThirtyTwoBitBigEndian bytesPerRow: 4 * 128 bitsPerPixel: 32]; [NSGraphicsContext setCurrentContext: [NSGraphicsContext graphicsContextWithBitmapImageRep: newRep]]; then the log shows this error: CGBitmapContextCreate: unsupported parameter combination: RGB 8 bits/component, integer 512 bytes/row kCGImageAlphaLast kCGImageByteOrderDefault kCGImagePixelFormatPacked Valid parameters for RGB color space model are: 16 bits per pixel, 5 bits per component, kCGImageAlphaNoneSkipFirst 32 bits per pixel, 8 bits per component, kCGImageAlphaNoneSkipFirst 32 bits per pixel, 8 bits per component, kCGImageAlphaNoneSkipLast 32 bits per pixel, 8 bits per component, kCGImageAlphaPremultipliedFirst 32 bits per pixel, 8 bits per component, kCGImageAlphaPremultipliedLast 32 bits per pixel, 10 bits per component, kCGImageAlphaNone|kCGImagePixelFormatRGBCIF10|kCGImageByteOrder16Little 64 bits per pixel, 16 bits per component, kCGImageAlphaPremultipliedLast 64 bits per pixel, 16 bits per component, kCGImageAlphaNoneSkipLast 64 bits per pixel, 16 bits per component, kCGImageAlphaPremultipliedLast|kCGBitmapFloatComponents|kCGImageByteOrder16Little 64 bits per pixel, 16 bits per component, kCGImageAlphaNoneSkipLast|kCGBitmapFloatComponents|kCGImageByteOrder16Little 128 bits per pixel, 32 bits per component, kCGImageAlphaPremultipliedLast|kCGBitmapFloatComponents 128 bits per pixel, 32 bits per component, kCGImageAlphaNoneSkipLast|kCGBitmapFloatComponents See Quartz 2D Programming Guide (available online) for more information. If I don't use NSBitmapFormatAlphaNonpremultiplied as part of the format, I don't get the error message. My question is, why does the constant NSBitmapFormatAlphaNonpremultiplied exist if you can't use it like this? If you're wondering why I wanted to do this: I want to extract the RGBA pixel data from an image, which might have non-premultiplied alpha. And elsewhere online, I saw advice that if you want to look at the pixels of an image, draw it into a bitmap whose format you know and look at those pixels. And I don't want the process of drawing to premultiply my alpha.
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3
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181
Activity
Jun ’25
Customize the Metal Performance HUD on Apple TV
Hi there, Is it possible to customize the Metal Performance HUD on Apple TV, similar to how it can be done on iPhone & iPad? Would like to see things like Compiled Shaders for my Apps on tvOS .
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3
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373
Activity
Aug ’25
Any way to save metrics presets as preferences in Metal HUD 4 on macOS?
I mean…I want to use defaults rather than launching apps via open with the saved environment variables. This is pretty easy on iOS and other platforms. So what about in macOS?
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3
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0
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446
Activity
Aug ’25
How to use MetalPeformancePrimitives
I am trying to learn the new Metal Peformance Primitives APIs. I have added the MetalPeformancePrimitives framework and included the header in my shader code as per documentation #include <MetalPeformancePrimitives/MetalPeformancePrimitives.h> Unfortunately, Xcode complains that the header cannot be found. How do I include it properly? I am using Xcode 26 on Tahoe. The MetalPeformancePrimitives framework is present on my machine and I can inspect the headers in the filesystem.
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3
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1
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789
Activity
Oct ’25
SwiftCharts to add candlestick and OHLC types to their stable?
I didn't find a suggestion box on Swift's website so I'll post it here. SwiftCharts are great but limited. I need more data on a single chart. Candlestick and OHLC type charts would be an excellent addition. Hopefully, influencers from Apple can make that happen. Thanks.
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3
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0
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258
Activity
Jun ’25
Clarifying when Game Center activity events fire relative to authentication
Hello, In our game we enforce an age gate before showing Game Center sign‑in. Only after the user passes the age gate do we call GKLocalPlayer.localPlayer.authenticateHandler. The reason I’m asking is that we want to reliably detect if the game was launched from a Game Center activity in the Games app (iOS 26+). If the user prefers to enter via activities, we don’t want to miss that event during cold start. Our current proposal is: Register a GKLocalPlayerListener early in didFinishLaunchingWithOptions: so the app is ready to catch events. Queue any incoming events in our dispatcher. Only process those events after the user passes the age gate and authentication succeeds. My questions are: Does player:wantsToPlayGameActivity:completionHandler: ever fire before authentication, or only after the local player is authenticated? If it only fires after authentication, is our “register early but gate processing” approach the correct way to ensure we don’t miss activity launches? Is there any recommended pattern to distinguish “activity launch” vs. “normal launch” in this age‑gate scenario? We want to respect Apple’s age gate requirements, but also ensure activity launches are not lost if the user prefers that entry point. Sorry if this is a stupid question — I just want to be sure we’re following the right pattern. Thanks for any clarification or best‑practice guidance!
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3
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0
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592
Activity
Feb ’26
CIBumpDistortion filter not working on my view
I'm trying to apply a CIBumpDistortion Core Image filter to a view that contains a UILabel (my storyLabel). The goal is to create a visual bump/magnifying glass effect over the text. However, despite my attempts, the filter doesn't seem to render at all. The view and the label appear as normal, with no distortion effect. I've tried adjusting the filter parameters and reviewing the view hierarchy, but without success. I also haven't been able to find clear documentation or examples for applying this filter to a UIView's layer. // // TVView.swift // Mistery // // Created by Joje on 31/07/25. // import CoreImage import CoreImage.CIFilterBuiltins import UIKit import AVFoundation final class TVView: UIView { // propriedades animacao texto private var textAnimationTimer: Timer? private var fullTextToAnimate: String = "" private var currentCharIndex: Int = 0 // propriedades video estatica private var player: AVQueuePlayer? private var playerLayer: AVPlayerLayer? private var playerLooper: AVPlayerLooper? var onNextButtonTap: () -> Void = {} // MARK: - Subviews // imagem da TV private(set) lazy var tvImageView: UIImageView = { let imageView = UIImageView() imageView.translatesAutoresizingMaskIntoConstraints = false imageView.image = UIImage(named: "tvFinal") imageView.contentMode = .scaleAspectFit return imageView }() // texto que passa dentro da TV private(set) lazy var storyLabel: UILabel = { let label = UILabel() label.translatesAutoresizingMaskIntoConstraints = false //label.backgroundColor = .gray label.textColor = .red label.font = UIFont(name: "MeltedMonster", size: 30) label.textAlignment = .left label.numberOfLines = 0 label.text = "" return label }() private(set) lazy var nextButton: UIButton = { let button = UIButton(type: .system) button.translatesAutoresizingMaskIntoConstraints = false //button.backgroundColor = .darkGray button.addTarget(self, action: #selector(didPressNextButton), for: .touchUpInside) return button }() // MARK: - Lifecycle override init(frame: CGRect) { super.init(frame: frame) backgroundColor = .black setupVideoPlayer() addSubviews() setupConstraints() } override func layoutSubviews() { super.layoutSubviews() playerLayer?.frame = tvImageView.frame.insetBy(dx: tvImageView.frame.width * 0.05, dy: tvImageView.frame.height * 0.18) setupFisheyeEffect() } private func setupFisheyeEffect() { // cria o filtro guard let filter = CIFilter(name: "CIBumpDistortion") else {return print("erro")} storyLabel.layer.shouldRasterize = true storyLabel.layer.rasterizationScale = UIScreen.main.scale // define os parametros filter.setDefaults() // centro do efeito let center = CIVector(x: storyLabel.bounds.midX, y: storyLabel.bounds.midY) filter.setValue(center, forKey: kCIInputCenterKey) // raio de distorção filter.setValue(storyLabel.bounds.width, forKey: kCIInputRadiusKey) // intensidade de distorção filter.setValue(7, forKey: kCIInputScaleKey) storyLabel.layer.filters = [filter] } required init?(coder: NSCoder) { fatalError("init(coder:) has not been implemented") } // MARK: - Button actions @objc private func didPressNextButton() { onNextButtonTap() } @objc private func animateNextCharacter() { guard currentCharIndex < fullTextToAnimate.count else { textAnimationTimer?.invalidate() return } let currentTextIndex = fullTextToAnimate.index(fullTextToAnimate.startIndex, offsetBy: currentCharIndex) let partialText = String(fullTextToAnimate[...currentTextIndex]) storyLabel.text = partialText currentCharIndex += 1 } public func updateStoryText(with text: String) { textAnimationTimer?.invalidate() storyLabel.text = "" fullTextToAnimate = text currentCharIndex = 0 textAnimationTimer = Timer.scheduledTimer(timeInterval: 0.12, target: self, selector: #selector(animateNextCharacter), userInfo: nil, repeats: true) } // MARK: - Setup methods private func setupVideoPlayer() { guard let videoURL = Bundle.main.url(forResource: "static-video", withExtension: "mov") else { print("Erro: Não foi possível encontrar o arquivo de vídeo static-video.mov") return } let playerItem = AVPlayerItem(url: videoURL) player = AVQueuePlayer(playerItem: playerItem) // LINHA COM POSSIVEL ERRO playerLooper = AVPlayerLooper(player: player!, templateItem: playerItem) playerLayer = AVPlayerLayer(player: player) playerLayer?.videoGravity = .resizeAspectFill if let layer = playerLayer { self.layer.addSublayer(layer) } player?.play() } private func addSubviews() { self.addSubview(storyLabel) self.addSubview(tvImageView) self.addSubview(nextButton) } private func setupConstraints() { NSLayoutConstraint.activate([ // TV Image tvImageView.centerXAnchor.constraint(equalTo: centerXAnchor), tvImageView.centerYAnchor.constraint(equalTo: centerYAnchor), tvImageView.widthAnchor.constraint(equalTo: widthAnchor), // TV Text storyLabel.centerXAnchor.constraint(equalTo: tvImageView.centerXAnchor, constant: -50), storyLabel.centerYAnchor.constraint(equalTo: tvImageView.centerYAnchor, constant: -25), storyLabel.widthAnchor.constraint(equalTo: tvImageView.widthAnchor, multiplier: 0.35), storyLabel.heightAnchor.constraint(equalTo: tvImageView.heightAnchor, multiplier: 0.42), //TV Button nextButton.topAnchor.constraint(equalTo: tvImageView.centerYAnchor, constant: -25), nextButton.centerXAnchor.constraint(equalTo: self.centerXAnchor, constant: 190), nextButton.widthAnchor.constraint(equalToConstant: 100), nextButton.heightAnchor.constraint(equalToConstant: 160) ]) } } #Preview{ ViewController() }
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3
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192
Activity
Sep ’25
How does the automatch feature work in Game Kit?
I'm developing a turn based game. When I present the GKTurnBasedMatchmakerViewController players can opt in for automatch instead of selecting a specific friend as opponent. How exactly does the matching work if a player doesn't specify anything explicitly? Does Game Center send push notifications in a round robin fashion to all friends and the first one to accept is then matched as opponent? Is this documented somewhere?
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3
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0
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518
Activity
Jan ’26
RealityView content scale factor
Hi, following the recent deprecation of SceneKit, I'm trying to move a couple of my SceneKit projects to RealityKit. One thing I can't seem to find is how to change the content scale factor when using a RealityView in SwiftUI. It was really easy to do in SceneKit with just a SCNView property, and it seems that it's also possible when using ARView, but I can't find a way to do it with a RealityView. Maybe it's a SwiftUI limitation?
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3
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1
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207
Activity
Jul ’25
Does VisionOS have the equivalent of ARView.physicsOrigin?
I'm trying to scale the physics of a scene without changing the apparent size to avoid the low-speed zeroing-out of motion that the physics simulation does. I found a technique for using separate simulation and physics roots in the docs, but it relies on ARView, which VisionOS doesn't have. This seems more elegant than scaling absolutely everything with shared root -- any chance I'm just failing in my searches to find the equivalent functionality?
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3
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1
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684
Activity
5d
App Freezes on iPadOS 26.x - GPU Metal Errors
I work on a Qt/QML app that uses Esri Maps SDK for Qt and that is deployed to both Windows and iPads. With a recent iPad OS upgrade to 26.1, many iPad users are reporting the application freezing after panning and/or identifying features in the map. It runs fine for our Windows users. I was able to reproduce this and grabbed the following error messages when the freeze happens: IOGPUMetalError: Caused GPU Address Fault Error (0000000b:kIOGPUCommandBufferCallbackErrorPageFault) IOGPUMetalError: Invalid Resource (00000009:kIOGPUCommandBufferCallbackErrorInvalidResource) Environment: Qt 6.5.4 (Qt for iOS) Esri Maps SDK for Qt 200.3 iPadOS 26.1 Because it appears to be a Metal error, I tried using OpenGL (Qt offers a way to easily set hte target graphics api): QQuickWindow::setGraphicsApi(QSGRendererInterface::GraphicsApi::OpenGL) Which worked! No more freezing. But I'm seeing many posts that OpenGL has been deprecated by Apple. I've seen posts that Apple deprecated OpenGL ES. But it seems to still be available with iPadOS 26.1. If so, will this fix (above) just cause problems with a future iPadOS update? Any other suggestions to address this issue? Upgrading our version of Qt + Esri SDK to the latest version is not an option for us. We are in the process to upgrade the full application, but it is a year or two out. So, we just need a fix to buy us some time for now. Appreciate any thoughts/insights....
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3
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0
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565
Activity
Dec ’25
GameKit Turn Based Matches Push Notifications
I'm developing a game that supports GameKit turn based matches. What I don't understand is this: Is tapping on the Game Center notification push messages the only way for the GKTurnBasedEventListener to trigger? What if someone misses the push message (swiping it away by accident or something like that) but still wants to join? Is there some inbox somewhere where the pending messages can be seen or fetched? Also it was mentioned in a very old WWDC video (from 2013, I think that's the latest with information about turn based matches) that the notification also includes a badge for the icon. However, I do not understand how to implement that. Is there any documentation for that?
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3
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0
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899
Activity
Jan ’26
RealityKit .Kinematic + collisions (visionOs)
Hi everyone, I'm new to visionOS development. I'm trying to create a physics-based scene (with gravity) where users can pick up and move objects on a workbench. I am struggling with physics interactions during the drag gesture: Kinematic Mode: If I switch to .kinematic during the drag, the object moves smoothly but clips through other objects (no collisions). Dynamic Mode: I tried keeping it .dynamic and applying linear velocity toward the hand position, but the movement feels laggy and unresponsive. Hybrid Approach: I tried switching to .kinematic during DragGesture.onChange and back to .dynamic on collision, but this causes the entity to jitter/shake violently when touching other objects. Has anyone found a clean way to drag objects while maintaining solid collisions. Thanks for your help!
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3
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0
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828
Activity
1w
Memory leak when no draw calls issued to encoder
I noticed that when the render command encoder adds no draw calls an apps memory usage seems to grow unboundedly. Using a super simple MTKView-based drawing with the following delegate (code at end). If I add the simplest of draw calls, e.g., a single vertex, the app's memory usage is normal, around 100-ish MBs. I am attaching a couple screenshot, one from Xcode and one from Instruments. What's going on here? Is this an illegal program? If yes, why does it not crash, such as if the encode or command buffer weren't ended. Or is there some race condition at play here due to the lack of draws? class Renderer: NSObject, MTKViewDelegate { var device: MTLDevice var commandQueue: MTL4CommandQueue var commandBuffer: MTL4CommandBuffer var allocator: MTL4CommandAllocator override init() { guard let d = MTLCreateSystemDefaultDevice(), let queue = d.makeMTL4CommandQueue(), let cmdBuffer = d.makeCommandBuffer(), let alloc = d.makeCommandAllocator() else { fatalError("unable to create metal 4 objects") } self.device = d self.commandQueue = queue self.commandBuffer = cmdBuffer self.allocator = alloc super.init() } func mtkView(_ view: MTKView, drawableSizeWillChange size: CGSize) {} func draw(in view: MTKView) { guard let drawable = view.currentDrawable else { return } commandBuffer.beginCommandBuffer(allocator: allocator) guard let descriptor = view.currentMTL4RenderPassDescriptor, let encoder = commandBuffer.makeRenderCommandEncoder( descriptor: descriptor ) else { fatalError("unable to create encoder") } encoder.endEncoding() commandBuffer.endCommandBuffer() commandQueue.waitForDrawable(drawable) commandQueue.commit([commandBuffer]) commandQueue.signalDrawable(drawable) drawable.present() } }
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3
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435
Activity
Jan ’26
Request: Allow Game Mode to be enabled locally for non-game App Store categories
Hi Apple team, Game Mode was introduced in iOS 18. To activate Game Mode, an app must include specific key-value pairs in its *.plist and be categorized as a "Game" on the App Store. My app (https://apps.apple.com/us/app/voidlink/id6747717070) works primarily as a self-hosted game streaming (PC->iPhone/iPad) client. Game Mode provides clear benefits in terms of latency and frame rate stability, but it can currently only be activated when running via Xcode or TestFlight. I am an individual iOS developer based in China, where an additional government license is required for apps to be listed under the "Game" category on the App Store. Obtaining such a license is very difficult for independent developers, so my app has been categorized under "Utilities" instead.(If move the app to game category, it will disappear from Chinese App Store immediately) Expectation / Suggestion: Please consider making Game Mode available as a local, user-controllable option on iOS18/26+, such as through a system “App Pool” where users can choose which apps to enable Game Mode for, regardless of App Store category. This would greatly benefit use cases like streaming clients, benchmarking tools, and remote play utilities, without requiring developers to reclassify their apps as “Games” on App Store.
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3
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1
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782
Activity
Nov ’25
Moving from SceneKit - fog missing
I am rewriting an unfinished SceneKit project as RealityKit (NonAR). As far as I can see, RealityKit is missing basic fog functionality? Fog was simple & easy to implement in SCeneKit (fogStartDistance / fogEndDistance / fogDensityExponent / fogColor). Are there any plans to implement something like this in RealityKit? Are there any simple workarounds?
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3
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1
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616
Activity
Aug ’25