Is there any standard way of efficiently showing a MTLTexture on a RealityKit Entity?
I can't find anything proper on how to , for example, generate a LowLevelTexture out of a MTLTexture. Closest match was this two year old thread.
In the old SceneKit app, we would just do
guard let material = someNode.geometry?.materials.first else { return }
material.diffuse.contents = mtlTexture
Our flow is as follows (for visualizing the currently detected object):
Camera-Stream -> CoreML Segmentation -> Send the relevant part of the MLShapedArray-Tensor to a MTLComputeShader that returns a MTLTexture -> Show the resulting texture on a 3D object to the user
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Apple, please bring back SceneKit.
In SceneKit, when creating an .scn file from a rigged model, the framework created an SCNNode for each bone/joint, so you could add and remove child nodes directly to and from joints, and like any other SCNNode, you could access world position and world orientation for each joint. The analog would be for joints to be accessible as child entities of a ModelEntity in RealityKit. I am unable to proceed with migrating my project from SceneKit because of this, as there does not seem to be a way to even access the true world position of a joint with the current jointNames/jointTransforms paradigm.
The translation information from the given transforms is insufficient to determine the location of a joint at any given time, and other approaches like creating a GeometricPin for the given joint name and attaching it to another entity do not seem to work. So conveniently being able to attach an item to the hand of a rigged model was trivial in SceneKit and now feels impossible in RealityKit.
I am not the first person to notice this, and am feeling demoralized about proceeding with RealityKit with such a critical piece of functionality blocked
https://stackoverflow.com/questions/76726241/how-do-i-attach-an-entity-to-a-skeletons-joint-in-realitykit
Will this be addressed in some way?
Hello
XQuartz is an open-source effort to develop a version of the X.Org X Window System (https://www.xquartz.org/), widely used to bring graphical support to applications running in remote servers (usually via SSH).
Since macOS Tahoe, XQuartz fails to refresh properly on window resize (more info here https://github.com/XQuartz/XQuartz/issues/438#issuecomment-3371409500), leading to severe usability issues.
The XQuartz developers are already aware of the issue, but I’m wondering if there’s anything we can do at the OS level to resolve it and restore the usual behavior from before macOS Tahoe.
Thanks,
KiM
Topic:
Graphics & Games
SubTopic:
General
I'm updating our app to support metal 4, but the metal 4 types don't seem to get recognized when targeting simulator. Is it known if metal 4 will be supported in the near future, or am I setting up the app wrong?
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.
Hello, we are working on a iOS game project, as progress, the project grows larger and larger. Because we are using other game dependencies and libraries, here larger and larger refers to the whole project, and our source files integrated and compiled by Xcode are not many. Now, it seems we hit a bottleneck, when I add new files or functions to the previous files to implement a new feature, Xcode compile stucks(stops), it's Indexing | Initializing datastore forever, cannot produce a final build.
macOS 15.1, Xcode 16.2
Can you provide any solutions to solve this problem?
Also submitted Feedback ID #FB18432749
Breaking Through PolySpatial's ~8k Object Limit – Seeking Alternative Approaches for Large-Scale Digital Twins
Confirmed: PolySpatial make Doubles MeshFilter Count – Hard Limit at ~8k Active Objects (15.9k Total)
Project Context & Research Goals
I’m developing an industrial digital twin application for Apple Vision Pro using Unity’s PolySpatial framework (RealityKit rendering in Unbounded_Volume mode). The scene contains complex factory environments with:
Production line equipment Many fragmented grid objects need to be merged.)
Dynamic product racks (state-switchable assets)
Animated worker avatars
To optimize performance, I’m systematically testing visionOS’s rendering capacity limits. Through controlled stress tests, I’ve identified a critical threshold:
Key Finding
When the total MeshFilter count reaches 15,970 (system baseline + 7,985 user-created objects × 2 due to PolySpatial cloning), the application crashes consistently. This suggests:
PolySpatial’s mirroring mechanism effectively doubles GameObject overhead
An apparent hard limit exists around ~8k active mesh objects in practice
Objectives for This Discussion
Verify if others have encountered similar limits with PolySpatial/RealityKit
Understand whether this is a:
Memory constraint (per-app allocation)
Render pipeline limit (Metal draw calls)
Unity-specific PolySpatial behavior
Explore optimization strategies beyond brute-force object reduction
Why This Matters
Industrial metaverse applications require rendering thousands of interactive objects . Confirming these limits will help our team:
Design safer content guidelines
Prioritize GPU instancing/LOD investments
Potentially contribute back to PolySpatial’s optimization
I’d appreciate insights from engineers who’ve:
Pushed similar large-scale scenes in visionOS
Worked around PolySpatial’s cloning overhead
Discovered alternative capacity limits (vertices/draw calls)
I am an AR developer working on Apple Silicon Macs. Currently, Reality Composer Pro does not allow exporting .reality files, and Reality Composer (classic) is not available for Apple Silicon. This creates a gap in the workflow for ARKit/RealityKit developers who need interactive .reality files for use in Xcode projects.
Having the ability to export .reality files directly from Reality Composer Pro on Mac would greatly streamline development and enable a fully native workflow on modern Macs. Alternatively, bringing Reality Composer (classic) to Apple Silicon would also resolve this issue.
I have submitted this as a feature request via Feedback Assistant (FB17900386). I encourage others with similar needs to reply or submit feedback as well.
Thank you!
Topic:
Graphics & Games
SubTopic:
RealityKit
Tags:
ARKit
Reality Composer
RealityKit
Reality Composer Pro
I have really enjoyed looking through the code and videos related to Metal 4. Currently, my interest is to update a ReSTIR Project and take advantage of more robust ways to refit acceleration Structures and more powerful ways to access resources.
I am working in Swift and have encountered a couple of puzzles:
What is the 'accepted' way to create a MTL4BufferRange to store indices and vertices?
How do I properly rewrite Swift code to build and compact an Acceleration Structure?
I do realize that this is all in Beta and will happily look through Code Samples this Fall. If other guidance is available earlier, that would be fabulous!
Thank you
I'm building a game with a client-server architecture. Using GKMatch.chooseBestHostingPlayer(_:) rarely works. When I started testing it today, it worked once at the very beginning, and since then it always succeeds on one client and returns nil on the other client. I'm testing with a Mac and an iPhone. Sometimes it fails on the Mac, sometimes on the iPhone. On the device that it succeeds on, the provided host can be the device itself or the other one.
I created FB9583628 in August 2021, but after the Feedback Assistant team replied that they are not able to reproduce it, the feedback never went forward.
import SceneKit
import GameKit
#if os(macOS)
typealias ViewController = NSViewController
#else
typealias ViewController = UIViewController
#endif
class GameViewController: ViewController, GKMatchmakerViewControllerDelegate, GKMatchDelegate {
var match: GKMatch?
var matchStarted = false
override func viewDidLoad() {
super.viewDidLoad()
GKLocalPlayer.local.authenticateHandler = authenticate
}
private func authenticate(_ viewController: ViewController?, _ error: Error?) {
#if os(macOS)
if let viewController = viewController {
presentAsSheet(viewController)
} else if let error = error {
print(error)
} else {
print("authenticated as \(GKLocalPlayer.local.gamePlayerID)")
let viewController = GKMatchmakerViewController(matchRequest: defaultMatchRequest())!
viewController.matchmakerDelegate = self
GKDialogController.shared().present(viewController)
}
#else
if let viewController = viewController {
present(viewController, animated: true)
} else if let error = error {
print(error)
} else {
print("authenticated as \(GKLocalPlayer.local.gamePlayerID)")
let viewController = GKMatchmakerViewController(matchRequest: defaultMatchRequest())!
viewController.matchmakerDelegate = self
present(viewController, animated: true)
}
#endif
}
private func defaultMatchRequest() -> GKMatchRequest {
let request = GKMatchRequest()
request.minPlayers = 2
request.maxPlayers = 2
request.defaultNumberOfPlayers = 2
request.inviteMessage = "Ciao!"
return request
}
func matchmakerViewControllerWasCancelled(_ viewController: GKMatchmakerViewController) {
print("cancelled")
}
func matchmakerViewController(_ viewController: GKMatchmakerViewController, didFailWithError error: Error) {
print(error)
}
func matchmakerViewController(_ viewController: GKMatchmakerViewController, didFind match: GKMatch) {
self.match = match
match.delegate = self
startMatch()
}
func match(_ match: GKMatch, player: GKPlayer, didChange state: GKPlayerConnectionState) {
print("\(player.gamePlayerID) changed state to \(String(describing: state))")
startMatch()
}
func startMatch() {
let match = match!
if matchStarted || match.expectedPlayerCount > 0 {
return
}
print("starting match with local player \(GKLocalPlayer.local.gamePlayerID) and remote players \(match.players.map({ $0.gamePlayerID }))")
match.chooseBestHostingPlayer { host in
print("host is \(String(describing: host?.gamePlayerID))")
}
}
}
I am developing a macOS terminal app, running on an M4 Pro, and using Metal.
I am not able use float8 or float16, both reporting Variable has incomplete type 'float16' (aka '__Reserved_Name__Do_not_use_float16').
Based on the system I should be able to use these. Either it is because it is also compiling to Intel, which they are not allowed, or something else. Either way I have not been able to figure out how to get past this.
IIs there a compiler setting I need to set to make this work? if so which one and what setting do I need? I only want to run this on M processes, on the latest version of OS so not interested in Intel version or backward compatibility.
I'm a newbee at Vulkan and Xcode.
I have my project on github https://github.com/flocela/OrangeSpider/
Whenever I run, two windows open instead of only one.
I added testing, which means I have an OrangeSpider.xctestplan in the OrangeSpider/TestsOrangeSpider/ folder.
This is my first time adding testing to an XCode project, so I think this may be where the problem is.
I also get this error message:
ViewBridge to RemoteViewService Terminated: Error Domain=com.apple.ViewBridge Code=18 "(null)" UserInfo={com.apple.ViewBridge.error.hint=this process disconnected remote view controller -- benign unless unexpected, com.apple.ViewBridge.error.description=NSViewBridgeErrorCanceled}
Topic:
Graphics & Games
SubTopic:
Metal
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!
We have a released game in the App Store with Game Center Challenges. The challenges were working well in testing of the final version before the Game Center challenges went live. After release the activity that should take the player to the challenge in game results in this printout and we do not get informed by GKGameActivityListener of the activity happening in our code as we did before the Game Center challenges went live.
“Invalid game activity definition.
Failed to kick activity notification to GameKit. Error: Error Domain=GKErrorDomain Code=17 "(null)"”
Also, Game Center reports that the are no challenges in GKChallengeDefinition.all even though there are ongoing challenges.
The leaderboard results do get reported to Game Center though and show up as challenge entries in the Games app.
At the moment we are trying to figure out if this is a problem on our end or a Game Center server issue.
Topic:
Graphics & Games
SubTopic:
GameKit
Hello,
I recently watched the WWDC2025 session titled “Combine Metal 4 machine learning and graphics” (https://developer.apple.com/videos/play/wwdc2025/262/ ), and I’m very excited about the new Metal 4 features that integrate machine learning with graphics—such as neural ambient occlusion, shader-based ML inference, and the use of MTLTensor and MTL4MachineLearningCommandEncoder.
While the session includes helpful code snippets and a compelling debug demo (e.g., the neural ambient occlusion example), the implementation details are not fully shown, and I haven’t been able to find a complete, runnable sample project that demonstrates end-to-end integration of ML and rendering in Metal 4.
Would Apple be able to provide a full, working example—such as an Xcode project—that shows how to:
Export a model to an .mlpackage,
Convert it to an .mtlpackage,
Use MTL4MachineLearningCommandEncoder alongside render passes,
Or embed small neural networks directly in shaders using Shader ML?
Having such a sample would greatly help developers like me adopt these powerful new capabilities correctly and efficiently.
Thank you very much for your time and support!
Best regards,
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?
Can I use them in SK and do the animations work?
Thanks, Patrick
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!
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!