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 .

If I compile a compute kernel with a call to texture.read(), it fails with the following error: "Error Domain=AGXMetalG13X Code=3 "Encountered unlowered function call to air.get_read_sampler" UserInfo={NSLocalizedDescription=Encountered unlowered function call to air.get_read_sampler}." This error occurs on both macOS and iOS 26 Beta 5, but not when running on a simulator or in a playground. It does not occur on a macOS Sequoia VM. It occurs whether I use the old metal 3 or new metal 4 compilation method. A workaround would be to use a sampler, but according to the feature tables, all platforms support reading from textures of all formats. Below is a minimal example which produces the error: let device = MTLCreateSystemDefaultDevice()! let library = device.makeDefaultLibrary()! let computeFunction = library.makeFunction(name: "compute_test")! do { let pipeline = try device.makeComputePipelineState(function: computeFunction) debugPrint(pipeline) } catch { debugPrint("Metal 3 failed with error:\n\(error)") } #import <metal_stdlib> using namespace metal; kernel void compute_test(uint2 gid [[thread_position_in_grid]], texture2d<float, access::read> in [[texture(0)]], texture2d<float, access::write> out [[texture(1)]]) { out.write(in.read(gid), gid); } I filed feedback FB19530049.

We executed the iOS package using UE5.5 on Windows. UE automatically launched the "Metal Developer Tools for Windows". I tried two versions, 5.3 and 4.4. I found that the metal.exe sometimes had no response or output was empty. The problem of no response could be alleviated by adding timeout retries, but the problem of empty output seemed to have no effect with retries. The actual command line called was: metal.exe -v --target=air64-apple-darwin18.7.0. UE relies on this output to determine the version number, and if it cannot get it, it will crash directly. During our replication test, we used a Python script to run multiple concurrent executions of the command "metal.exe -v --target=air64-apple-darwin18.7.0". On different Windows machines, it would get stuck at a certain concurrency level. Some machines even got stuck when running two tasks concurrently. We would like to ask for solutions or available versions.

Hi! I'm currently trying to render another XR scene in front of a RealityKit one. Actually, I'm anchoring a plane to the head with a shader to display for left/right eye side-by-side images. By default, the camera has a near plane so I can directly draw at z=0. Is there a way to change the camera near plane? Or maybe there is a better solution to overlay image/texture for left/right eyes? Ideally, I would layer some kind of CompositorLayer on RealityKit, but that's sadly not possible from what I know. Thanks in advance and have a good day!

Hello! I'm developing a GPU (shader) language, where I aim to target multiple backends with a common frontend. I wanted to avoid having to round trip through Metal, and go straight to IR just like I have with SPIRV, in order to have a fast and efficient compilation process. I've been looking for a reference page where I can read about Metals IR, and as far as I'm aware, it exists, but I can't seem to find it anywhere. Furthermore, if such a reference is available, is there also a toolkit where I can run validation on the output IR, and perhaps even run optimizations, much like spv-tools for SPIRV? Any help would be appreciated! Thanks, Gustav

Hello everyone, I must have missed something but why isn't there a depthAttachmentPixelFormat to the new Metal 4 MTL4RenderPipelineDescriptor, unlike the old MTLRenderPipelineDescriptor? So how do you set the depth pixel format? Thanks in advance!

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!

Hello, I'm tracking down a bug where useResource doesn't seem to apply proper synchronization when a resource is produced by the render pass then consumed by the compute pass, but when I use MTLFence between the to signal and wait between the render/compute encoders, the artifact goes away. The resource is created with MTLHazardTrackingModeTracked and useResource is called on the compute encoder after the render pass. Metal API Validation doesn't report any warnings/errors. Am I misunderstanding the difference between the two APIs? I dug through the Metal documentation and it looks like useResource should handle synchronization given the resource has MTLHazardTrackingModeTracked but on the other hand, MTLFence should be used to ensure proper synchronization between command encoders. Can someone can clarify the difference between the two APIs and when to use them.

I have discovered that RemoteImmersiveSpace is limited to utilizing the structure of the CompositorContent protocol, precluding direct invocation of RealityView. Consequently, I am interested in understanding the appropriate method for integrating CompositorContent within RemoteImmersiveSpace. Thanks.

WWDC25: Combine Metal 4 machine learning and graphics Demonstrated a way to combine neural network in the graphics pipeline directly through the shaders, using an example of Texture Compression. However there is no mention of using which ML technique texture is compressed. Can anyone point me to some well known model/s for this particular use case shown in WWDC25.

When I play an HDR video in the iPhone Photos app, I can see the HDR effect obviously. But if this HDR video is played continuously for more than 30-40 minutes, the HDR effect will disappear and the brightness will be compressed to the SDR range. This issue will appear on any iPhone. Depending on the phone, it may be 20-30 minutes, or 30-40 minutes, or even a few minutes, such as iPhone 12 mini. Similarly, if I use AVPlayer to play and preview an HDR video, if it plays more than 30-40 minutes, the HDR effect will disappear and the screen brightness will dim. Also the currentEDRHeadroom will gradually decrease to 1 Note, test it with an HDR video longer than 1 hour, and if the video is short, please loop it. My question is how to avoid losing the HDR effect after 30-40 minutes when I use CAMetalLayer to render any HDR video.

When i use AVPlayer to obtain the video frame CVPixelBufferRef of an HDR video, and use AVSampleBufferDisplayLayer to display it on the screen, after a period of time, the HDR video content and screen gradually darken, losing the HDR effect. Steps to reproduce: Create an AVPlayer to loop an HDR video, specify the video frame format as kCVPixelFormatType_420YpCbCr10BiPlanarVideoRange Create a timer to get the video frame CVPixelBufferRef at 30 frames per second Use AVSampleBufferDisplayLayer to display CVPixelBufferRef on the screen Don't operate the phone, wait for a period of time (such as 40 minutes), the HDR effect disappears and the screen darkens Note: You need to use an iPhone device, iOS 18.5 and below operating system You need to ensure that the HDR video is played in a loop, that is, to ensure that the screen continues to display HDR content, wait for a period of time, depending on different devices, you need to wait for 20-40 minutes. In the iPhone Photos app,the same problem will occur after playing HDR video in a loop for a long time Expected Results: When rendering HDR content for a long time, it is guaranteed that there is always an HDR effect, and the HDR content and screen will not be darkened. Current Results: After about 20-40 minutes, the HDR effect disappears and the screen darkens.

Hi , My application meet below crash backtrace at very low repro rate from the public users, i do not see it relate to a specific iOS version or iPhone model. The last code line from my application is calling CAMetalLayer nextDrawable API. I did some basic studying, suppose it may relate to the wrong CAMetaLayer configuration, like frame property w or h <= 0.0 bounds property w or h <= 0.0 drawableSize w or h <= 0.0 or w or h > max value (like 16384) Not sure my above thinking is right or not? Will the UIView which my CAMetaLayer attached will cause such nextDrawable crash or not ? Thanks a lot Main Thread - Crashed libsystem_kernel.dylib __pthread_kill libsystem_c.dylib abort libsystem_c.dylib __assert_rtn Metal MTLReportFailure.cold.1 Metal MTLReportFailure Metal _MTLMessageContextEnd Metal -[MTLTextureDescriptorInternal validateWithDevice:] AGXMetalA13 0x245b1a000 + 4522096 QuartzCore allocate_drawable_texture(id<MTLDevice>, __IOSurface*, unsigned int, unsigned int, MTLPixelFormat, unsigned long long, CAMetalLayerRotation, bool, NSString*, unsigned long) QuartzCore get_unused_drawable(_CAMetalLayerPrivate*, CAMetalLayerRotation, bool, bool) QuartzCore CAMetalLayerPrivateNextDrawableLocked(CAMetalLayer*, CAMetalDrawable**, unsigned long*) QuartzCore -[CAMetalLayer nextDrawable] SpaceApp -[MetalRender renderFrame:] MetalRenderer.mm:167 SpaceApp -[FrameBuffer acceptFrame:] VideoRender.mm:173 QuartzCore CA::Display::DisplayLinkItem::dispatch_(CA::SignPost::Interval<(CA::SignPost::CAEventCode)835322056>&) QuartzCore CA::Display::DisplayLink::dispatch_items(unsigned long long, unsigned long long, unsigned long long) QuartzCore CA::Display::DisplayLink::dispatch_deferred_display_links(unsigned int) UIKitCore _UIUpdateSequenceRun UIKitCore schedulerStepScheduledMainSection UIKitCore runloopSourceCallback CoreFoundation __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ CoreFoundation __CFRunLoopDoSource0 CoreFoundation __CFRunLoopDoSources0 CoreFoundation __CFRunLoopRun CoreFoundation CFRunLoopRunSpecific GraphicsServices GSEventRunModal UIKitCore -[UIApplication _run] UIKitCore UIApplicationMain

hi everyone, 我们发现了一个和Metal相关崩溃。应用中使用了Metal相关的接口，在进行性能测试时，打开了设置-开发者-显示HUD图形。运行应用后，正常展示HUD，但应用很快发生了崩溃，日志主要信息如下： Incident Identifier: 1F093635-2DB8-4B29-9DA5-488A6609277B CrashReporter Key: 233e54398e2a0266d95265cfb96c5a89eb3403fd Hardware Model: iPhone14,3 Process: waimai [16584] Path: /private/var/containers/Bundle/Application/CCCFC0AE-EFB8-4BD8-B674-ED089B776221/waimai.app/waimai Identifier: Version: 61488 (8.53.0) Code Type: ARM-64 Parent Process: ? [1] Date/Time: 2025-06-12 14:41:45.296 +0800 OS Version: iOS 18.0 (22A3354) Report Version: 104 Monitor Type: Mach Exception Exception Type: EXC_BAD_ACCESS (SIGBUS) Exception Codes: KERN_PROTECTION_FAILURE at 0x000000014fffae00 Crashed Thread: 57 Thread 57 Crashed: 0 libMTLHud.dylib esfm_GenerateTriangesForString + 408 1 libMTLHud.dylib esfm_GenerateTriangesForString + 92 2 libMTLHud.dylib Renderer::DrawText(char const*, int, unsigned int) + 204 3 libMTLHud.dylib Overlay::onPresent(id<CAMetalDrawable>) + 1656 4 libMTLHud.dylib CAMetalDrawable_present(void (*)(), objc_object*, objc_selector*) + 72 5 libMTLHud.dylib invocation function for block in void replaceMethod<void>(objc_class*, objc_selector*, void (*)(void (*)(), objc_object*, objc_selector*)) + 56 6 Metal __45-[_MTLCommandBuffer presentDrawable:options:]_block_invoke + 104 7 Metal MTLDispatchListApply + 52 8 Metal -[_MTLCommandBuffer didScheduleWithStartTime:endTime:error:] + 312 9 IOGPU IOGPUNotificationQueueDispatchAvailableCompletionNotifications + 136 10 IOGPU __IOGPUNotificationQueueSetDispatchQueue_block_invoke + 64 11 libdispatch.dylib _dispatch_client_callout4 + 20 12 libdispatch.dylib _dispatch_mach_msg_invoke + 464 13 libdispatch.dylib _dispatch_lane_serial_drain + 368 14 libdispatch.dylib _dispatch_mach_invoke + 456 15 libdispatch.dylib _dispatch_lane_serial_drain + 368 16 libdispatch.dylib _dispatch_lane_invoke + 432 17 libdispatch.dylib _dispatch_lane_serial_drain + 368 18 libdispatch.dylib _dispatch_lane_invoke + 380 19 libdispatch.dylib _dispatch_root_queue_drain_deferred_wlh + 288 20 libdispatch.dylib _dispatch_workloop_worker_thread + 540 21 libsystem_pthread.dylib _pthread_wqthread + 288 我们测试了几个不同的机型，只有iPhone 13 Pro Max会发生崩溃。 Q1：为什么会发生这个崩溃？ Q2：相同的逻辑，为什么仅在iPhone 13 Pro Max机型上出现崩溃？ 期待您的解答。

Hello experts, I'm trying to implement a material with custom shader code, but I saw that visionOS doesn't allow you to inject custom Metal functions or use CustomMaterial like iOS/macOS, nor can you directly write Metal Shading Language (.metal) and use it through ShaderGraphMaterial. So my question is, if i want to implement your own shader code, how should i do it?

Hi all, I'm running into an issue with an app that previously worked fine on device using visionOS 2.0. After updating to visionOS 26, the same code runs fine in the simulator but crashes on the device with the following error: -[MTLDebugComputeCommandEncoder _validateThreadsPerThreadgroup:]:1330: failed assertion `(threadsPerThreadgroup.width(32) * threadsPerThreadgroup.height(32) * threadsPerThreadgroup.depth(1))(1024) must be <= 832. (kernel threadgroup size limit)` Is there any documented way to check or increase the allowed threadsPerThreadgroup size on Apple Vision Pro? Or any recommended workaround for this regression? Thanks in advance!

Hi there, I'm wondering if it's possible under iOS 28 developer beta to enable MetalFX scaling info with '{"MTL_HUD_ENABLED": "1" for my App. This information has been added to Mac, but looks to be absent on iPhone / iPad

I'm using a class with tangents to render on RealityKit for VisionOS but in Vision26 it cause a crash on App and there not documentation how implement cp_drawable_compute_projection I have tried a few options but without success. Could you help me to implement it ? The part of code is: return drawable.views.map { view in let userViewpointMatrix = (simdDeviceAnchor * view.transform).inverse let projectionMatrix = ProjectiveTransform3D( leftTangent: Double(view.tangents[0]), rightTangent: Double(view.tangents[1]), topTangent: Double(view.tangents[2]), bottomTangent: Double(view.tangents[3]), nearZ: Double(drawable.depthRange.y), farZ: Double(drawable.depthRange.x), reverseZ: true ) let screenSize = SIMD2(x: Int(view.textureMap.viewport.width), y: Int(view.textureMap.viewport.height)) return ModelRendererViewportDescriptor(viewport: view.textureMap.viewport, projectionMatrix: .init(projectionMatrix), viewMatrix: userViewpointMatrix * translationMatrix * rotationMatrix * scalingMatrix * commonUpCalibration, screenSize: screenSize) }

I maintain a couple of CoreImage libraries that provide custom Metal kernel backed CIFilters. In iOS/iPadOS 26, the CIColorKernel.apply() method invoked in the CIFilter subclass fails to add the coreimage::destination parameter to the Metal function call: -[CIColorKernel applyWithExtent:arguments:options:] argument count mismatch for kernel 'FractalNoise3D', expected 13 but saw 12. I've compiled the code with Xcode 26 and deployed to iOS 18 devices without any breakage, so this is definitely an iOS problem, not an Xcode problem. Library here: https://github.com/JoshuaSullivan/SimplexNoiseFilter Feedback ID: FB17874311

I'm building a weather map that shows the rain on the map. I'm able to retrieve PNG images that are used as tiles to put onto the map. I then reload all the tiles on the map with each timeframe (tile set for every 10 minutes). I'm able to get the map loaded up and I'm able to place the tiles and reload the data for each time slot. I preload all the PNG data needed for the tiles and store that NSData for them in memory so that they are quick for loading and showing on the map. I have timer's set to reload the overlay with the next set of tiles for each time slot. Giving the view of a moving precipitation map over time (just like you'd see on any weather map.) I have 12 time slots (timestamps) showing every 10 minutes for the past 2 hours. I have it showing each in sequence and then repeating. Over time I get a crash with this error as a Thread 1: signal SIGABRT. Failed to acquire drawable, rendering to temporary texture validateRenderPassDescriptor:782: failed assertion `RenderPass Descriptor Validation MTLRenderPassAttachmentDescriptor MTLStoreActionMultisampleResolve store action at attachment 0 requires resolve texture ' validateRenderPassDescriptor:782: failed assertion `RenderPass Descriptor Validation MTLRenderPassAttachmentDescriptor MTLStoreActionMultisampleResolve store action at attachment 0 requires resolve texture ' Through some searching I've discovered that this seems to be console output from Metal. I assume Metal is used for MapKit to render the overlay tiles? I'm using the same custom overlay where I set the timestamp on it and then tell it to reload. I also reuse the same MKOverlayRenderer as shown here... - (MKOverlayRenderer*)mapView:(MKMapView*)mapView rendererForOverlay:(id<MKOverlay>)overlay { if ([overlay isKindOfClass:[MKTileOverlay class]]) { if (!self.rainRenderer) { self.rainRenderer = [[MKTileOverlayRenderer alloc] initWithTileOverlay:overlay]; self.rainRenderer.alpha = 0.5; } return self.rainRenderer; } return nil; } And here's the function that reloads the overlay... - (void) updateRainFrame { self.currentFrameIndex = (self.currentFrameIndex + 1) % self.timestamps.count; if ((self.currentFrameIndex >= 0) && (self.timestamps.count > self.currentFrameIndex)) { NSLog (@"self.currentFrameIndex = %lu", self.currentFrameIndex); NSString *timestamp = self.timestamps[self.currentFrameIndex]; [self.overlay setTimestamp:timestamp]; [self.rainRenderer reloadData]; } } The time it takes to crash seems arbitrary. Sometimes it's very quick. Less than a minute. But usually it's several minutes. 10 or 20 minutes or more. Feels like some sort of race condition that's occurring. Perhaps ARC is not able to release the images for the tiles quick enough for each overlay reload? That's a wild guess but I think it's something more deeper in Metal as I feel I would see other errors related to memory availability. Some of my searches point to something about MSAA needing to be turned off in Metal to resolve this. However I have no idea how I would do that through MapKit. Any suggestions? Let me know if there is somehow a way to capture more from the crash to give more insight.