I'm looking to create an effect on iOS that tracks the user's face position with ARKit and shifts nearer/more prominent geometry in the scene around while more "distant" geometry stays fixed to the XY plane - making it look like the geometry on screen "sticks out"
I've managed to implement most of this successfully, but it's not perfect when using PerspectiveCameraComponent in RealityKit because as I shift the camera (and change its field of view based on the user's distance) the backplane changes its orientation (it's always orthogonal to camera's direction).
I've tried adopting ProjectiveTransformCameraComponent instead. The idea is that the camera shifts around the scene, mirroring the user's head's position, looking at (0,0,0) and the back plane is adjusted to be parallel with the X,Y plane (animation replicated in Blender below).
However, I can't manage to set up ProjectiveTransformCameraComponent with an appropriate matrix or update its transform property in a RealityKit System correctly.
I also tried setting many simpler projection matrices as described in a number of guides on camera projection matrices on the internet and all I get is a blank view.
Does anyone have some guidance on what the projection matrix that ProjectiveTransformCameraComponent expects is meant to look like or how I would go about accomplishing my goal?
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I am trying to install the Game Porting Toolkit 2.1 according to the Readme file provided with the toolkit.
When I run the following command:
WINEPREFIX=~/my-game-prefix brew --prefix game-porting-toolkit/bin/wine64 winecfg
I get an error message:
zsh: no such file or directory: /usr/local/opt/game-porting-toolkit/bin/wine64
I don't know how to resolve this.
When I type in the command which brew , I get the path
/usr/local/bin/brew
What am I doing wrong?
I have been trying to run an open source Windows executable that I would like to help porting to macOS using the Game Porting Toolkit but I stumbled on an issue quite early in the application lifecycle.
It looks like the funtion GetThreadDpiHostingBehavior is missing in USER32.dll
Has anyone any idea how to solve that?
During the startup, it fails with the following error:
TiXL crashed. We're really sorry.
The last backup was saved Unknown time to...
C:\users\crossover\AppData\Roaming\TiXL\Backup
Please refer to Help > Using Backups on what to do next.
System.EntryPointNotFoundException: Unable to find an entry point named 'GetThreadDpiHostingBehavior' in DLL 'USER32.dll'.
at System.Windows.Forms.ScaleHelper.DpiAwarenessScope..ctor(DPI_AWARENESS_CONTEXT context, DPI_HOSTING_BEHAVIOR behavior)
at System.Windows.Forms.ScaleHelper.EnterDpiAwarenessScope(DPI_AWARENESS_CONTEXT awareness, DPI_HOSTING_BEHAVIOR dpiHosting)
at System.Windows.Forms.NativeWindow.CreateHandle(CreateParams cp)
at System.Windows.Forms.Control.CreateHandle()
at System.Windows.Forms.Application.ThreadContext.get_MarshallingControl()
at System.Windows.Forms.WindowsFormsSynchronizationContext..ctor()
at System.Windows.Forms.WindowsFormsSynchronizationContext.InstallIfNeeded()
at System.Windows.Forms.Control..ctor(Boolean autoInstallSyncContext)
at System.Windows.Forms.ScrollableControl..ctor()
at System.Windows.Forms.ContainerControl..ctor()
at System.Windows.Forms.Form..ctor()
at T3.Editor.SplashScreen.SplashScreen.SplashForm..ctor()
at T3.Editor.SplashScreen.SplashScreen.Show(String imagePath) in C:\Users\pixtur\dev\tooll\tixl\Editor\SplashScreen\SplashScreen.cs:line 25
at T3.Editor.Program.Main(String[] args) in C:\Users\pixtur\dev\tooll\tixl\Editor\Program.cs:line 111
Hi all im having a variety of issues with gamekit matchmaking. On the simulator the matchmaking ui pops up and I can click Quick Match, then immediately "Failed to find Players" this is the same with a real Apple ID and a sandbox account.
If I use real devices the app at least discovers a match, but then the match none of the delegate methods for the match ever get called and the logs are filled with socket not connected and various errors.
My questions are:
Should match making via quick match work in the simulator, I have seen tutorial videos etc of this working, but I can't seem to get it to work.
How do people debug issues with GameCenter / Gamekit to find out why its not able to connect?
Many thanks in advance
I have run into an issue where I am trying to use atomic_float in a swift package but I cannot get things to compile because it appears that the Swift Package Manager doesn't support Metal 3 (atomic_float is Metal 3 functionality). Is there any way around this? I am using
// swift-tools-version: 6.1
and my Metal code includes:
#include <metal_stdlib>
#include <metal_geometric>
#include <metal_math>
#include <metal_atomic>
using namespace metal;
kernel void test(device atomic_float* imageBuffer [[buffer(1)]],
uint id [[ thread_position_in_grid ]]) {
}
But I get an error on the definition of atomic_float .
Any help, one more importantly, where I could have found this information about this limitation, would be helpful.
-RadBobby
Topic:
Graphics & Games
SubTopic:
Metal
Hi everyone,
I’m currently learning about ParticleEmitterComponentParticleEmitterComponent and exploring the sample app provided in the Simulating particles in your visionOS app documentation.
In the sample app, when I set the EmitterPreset to fireworks from the settings panel on the left side of the window and choose SystemImage, I noticed two issues:
The image applied to mainEmitter appears clipped or cropped.
The image on spawnedEmitter does not update to the selected SystemImage.
What I want to achieve:
Apply the same SystemImage to both mainEmittermainEmitter and spawnedEmitterspawnedEmitter so that it displays correctly without clipping.
Remove the animation that changes the size of spawnedEmitterspawnedEmitter over time and keep it at a constant size.
Could someone explain which properties should be adjusted to achieve this behavior? Any guidance or examples would be greatly appreciated.
Thanks in advance!
Hello
I am trying to get thread group memory access in fragment shader. In essence, I would like to have all the fragments in a tile to bitwiseOR some value. My idea was to use simd_or across the SIMD group, then make each SIMD group thread 0 to atomic or the value into thread group memory. Finally very first thread of the tile would be tasked with writing the value down to texture with write access.
Now, I can allocate the thread group memory argument to the fragment function all right. MTLRenderEncoder has setThreadgroupMemoryLength call, which I am using the following way
[renderEncoder setThreagroupMemoryLength: 16 offset: 0 atIndex:0]
Unfortunately, all I am getting is the following error (runtime assertion)
-[MTLDebugRenderCommandEncoder setThreadgroupMemoryLength:offset:atIndex:]:3487: failed assertion Set Threadgroup Memory Length Validation
offset + length(16) must be <= threadgroupMemoryLength(0).`
What I am doing wrong? How I can get thread group memory in the fragment shader? I know I could use tile shading and compute function but the problem is that here I really like to use fragment stuff. Will be grateful for help.
I have two devices (iPod, iPhone), each using a different Apple ID. I have an existing game to which I'm adding TBM. When the iPod invites the iPhone, it sends an iMessage invite to the iPhone; when I click on that message, I get "Retrieving", then Game Center in Settings is opened, not my App (same version installed on both devices). I start my App on the iPhone and that match is not shown in the Matchmaker View Controller.
When I send an invite from the iPhone to the iPod and I click on the iMessage invite, the app starts but the match isn't listed in the MatchMaker ViewController on the iPod (but is on the iPhone).
In addition, when I click on the info circle on the iPhone, it who's the two players and "App Store" under the Game Center name. However, When I do the same on the iPod, it has a "Play your turn" there.
Any ideas?
Hello, when I'm looking to customize the icons of my phone, the applications that are in the grouping genres without replacing with all-black images, I don't know what happens by changing the color of the applications in group of change no color throws just listen not the black stuff
Topic:
Graphics & Games
SubTopic:
General
Hello,
I am experiencing an issue with programmatically capturing a GPU trace using MTLCaptureManager. The .gputrace file that is generated appears to be corrupted, and I'm looking for guidance or a solution.
Description of the Problem:
I am using MTLCaptureManager.sharedCaptureManager to capture a Metal frame and save it to disk.
The generated .gputrace file is consistently reported as 0 bytes in size by the file system.
Crucially, when I compress this 0-byte .gputrace file into a .zip archive, the resulting archive contains the full, expected data. After unzipping, the file can be opened and viewed correctly in Xcode.
However,When inspecting the file's contents using NSFileManager in Objective-C (treating it as a directory), the internal structure is different from a .gputrace file captured directly from Xcode's Metal Debugger.
capture in xcode
capture in file
Finally,When capturing multiple frames programmatically, the first captured frame contains valid buffer data. However, for subsequent frames (starting from the second frame), the corresponding buffer contents are all zero-filled.
Frame 1: All MTLBuffer data is correctly captured and populated.
Frame 2 and onward: The same MTLBuffer objects are present in the trace, but their contents are entirely 0 (i.e., the data is not captured or is corrupted).
In this case, the on-screen display is normal, but the captured frame is incorrect. The frame captured directly in Xcode is also correct. Only the frame captured to a file is abnormal.
Topic:
Graphics & Games
SubTopic:
Metal
Problem Summary
After upgrading to iOS 26.1 and 26.2, I'm experiencing a particle positioning bug in RealityKit where ParticleEmitterComponent particles render at an incorrect offset relative to their parent entity. This behavior does not occur on iOS 18.6.2 or earlier versions, suggesting a regression introduced in the newer OS builds.
Environment Details
Operating System: iOS 26.1 & iOS 26.2
Framework: RealityKit
Xcode Version: 16.2 (16C5032a)
Expected vs. Actual Behavior
Expected: Particles should render at the position of the entity to which the ParticleEmitterComponent is attached, matching the behavior on iOS 18.6.2 and earlier.
Actual: Particles appear away from their parent entity, creating a visual misalignment that breaks the intended AR experience.
Steps to Reproduce
Create or open an AR application with RealityKit that uses particle components
Attach a ParticleEmitterComponent to an entity via a custom system
Run the application on iOS 26.1 or iOS 26.2
Observe that particles render at an offset position away from the entity
Minimal Code Example
Here's the setup from my test case:
Custom Component & System:
struct SparkleComponent4: Component {}
class SparkleSystem4: System {
static let query = EntityQuery(where: .has(SparkleComponent4.self))
required init(scene: Scene) {}
func update(context: SceneUpdateContext) {
for entity in context.scene.performQuery(Self.query) {
// Only add once
if entity.components.has(ParticleEmitterComponent.self) { continue }
var newEmitter = ParticleEmitterComponent()
newEmitter.mainEmitter.color = .constant(.single(.red))
entity.components.set(newEmitter)
}
}
}
AR Setup:
let material = SimpleMaterial(color: .gray, roughness: 0.15, isMetallic: true)
let model = Entity()
model.components.set(ModelComponent(mesh: boxMesh, materials: [material]))
model.components.set(SparkleComponent4())
model.position = [0, 0.05, 0]
model.name = "MyCube"
let anchor = AnchorEntity(.plane(.horizontal, classification: .any, minimumBounds: [0.2, 0.2]))
anchor.addChild(model)
arView.scene.addAnchor(anchor)
Questions for the Community
Has anyone else encountered this particle positioning issue after updating to iOS 26.1/26.2?
Are there known workarounds or configuration changes to ParticleEmitterComponent that restore correct positioning?
Is this a confirmed bug, or could there be a change in coordinate system handling or transform inheritance that I'm missing?
Additional Information
I've already submitted this issue via Feedback Assistant(FB21346746)
When running on my iPhone SE3 under IOS 18.4.1, achievement banners show as expected. The same code running on my iPad Air2 under IOS 15.8.4, achievement banners do not show, but they are accepted (as shown in the GameCenterViewController). The banners also don't show when running the simulator under iPhone 16 Pro Max under IOS 18.2 or simulator under iPhone SE3 under IOS 18.3. I haven't tried others. [Note that I clear the achievements each run during test so that I can duplicate this]
Topic:
Graphics & Games
SubTopic:
GameKit
App Storeにある『浮遊時計 Premium』は1Hzごとか10Hzごと、または3段階以上のリフレッシュレート計測はできますか?
Topic:
Graphics & Games
SubTopic:
General
Hello!
I have a question about how thread groups work with tile shading. When running "traditional" compute, I get to choose both thread group size and the grid size. However, when using tile shading kernel I only have dispatchThreadsPerTile method - this controls how many threads will be ran in each tile. So far so good, but what about thread groups?
The examples in video "Tile Shading on A11" seem to suggest that there will be only one thread group per tile. In the video, [[thread_index_in_threadgroup]] is called "local_id" and it is used to access the image block.
I assume this is the default configuration. So when one does the following:
Creates MTLRenderPassDescriptor with tileWidth set to W and tileHeight set to H
Fires up the tile shading kernel using dispatchThreadsPerTile with MTLSize size = { W, H, 1 }
I understand that the result is 1-to-1 mapping between the tile "pixels" and kernel threads. Now, what I would like to do is to have more than one thread group there. I want this for performance reasons: I have a certain compute kernel which I know executes very well with small thread group size. In fact, { 32, 1, 1 } seems to be the fastest. My understanding is that even if I set tile size to 16x16, and so I am executing 256 threads there, there will only be one SIMD group active in a thread group. Meaning that this SIMD group has to execute 8 times over the tile.
Is it possible somehow? Or perhaps the limitations of the API are pointing at the limitations of hardware itself, and if I want to execute with SIMD group sized thread groups I have to use "traditional" compute encoder?
Will be grateful for help.
Michał
Code is download from apple official metal4 sample
[https://developer.apple.com/documentation/metal/drawing-a-triangle-with-metal-4?language=objc]
enable metal gpu trace in macOS schema and trace a frame in Xcode.
Xcode may show segment fault on App from some 'GTTrace' function when click trace button.
When replay a .gputrace file, Xcode may crash , throw an internal error or a XPC error.
The example code using old metal-renderer can trace without any problem and everything works fine.
Test Environment:
Xcode Version 26.2 (17C52)
macOS 26.2 (25C56)
M1 Pro 16GB A2442
Hello I trying to implement authentication via apple services in unity game with server made as another unity app On client side I succesfully got teamPlayerID signature salt timestamp publicKeyUrl According to this documentation https://developer.apple.com/documentation/gamekit/gklocalplayer/fetchitems(foridentityverificationsignature:)?language=objc
I have to
Verify with the appropriate signing authority that Apple signed the public key.
As I said my server is special build of unity project So now I have this kind of C# programm to check apple authority over public certificate i got from publicKeyUrl
TextAsset textAsset;
byte[] bytes;
textAsset = Resources.Load<TextAsset>("AppleRootCA-G3");
bytes = textAsset.bytes;
rootCert.ChainPolicy.ExtraStore.Add(new X509Certificate2(bytes));
textAsset = Resources.Load<TextAsset>("AppleRootCA-G2");
bytes = textAsset.bytes;
rootCert.ChainPolicy.ExtraStore.Add(new X509Certificate2(bytes));
textAsset = Resources.Load<TextAsset>("AppleIncRootCertificate");
bytes = textAsset.bytes;
rootCert.ChainPolicy.ExtraStore.Add(new X509Certificate2(bytes));
rootCert.Build(cert);
Where cert is X509Certificate2 object I ge from publicKeyUrl
AppleIncRootCertificate AppleRootCA-G2 AppleRootCA-G3 is certificates I got from https://www.apple.com/certificateauthority/
But it is not work Anytime rootCert.Build(cert); return false Why it is not work? May be I build keychain using wrong root CA cert? Or whole approach incorrect? Please help
In my game 854159268 (com.1791entertainment.qugame), in my quMostRecent3 leaderboard, the top 2 entries have 'vanished'. They were there yesterday. I know these players have played today, as I see their scores on other leaderboards.
Any ideas how to get these back?
These 2 players (me and my tester) are both TestFlight ing - not sure if that changes things.
Topic:
Graphics & Games
SubTopic:
GameKit
After updating iPad/iPhone devices from iOS 18 to iOS 26, PhotogrammetrySession intermittently crashes during photogrammetry processing. The same workflow was stable on iOS 18 with no code changes to the app.
Environment:
OS versions: Works on OS 18, crashes on OS 26
Device: iPad/iPhone (reproducible across devices)
Source images: ~170-200 JPG files at 2160 x 3840 resolution
Reproduction:
The crash occurs consistently on the second or third sequential run of the photogrammetry session with the same image set. First run typically succeeds.
Crash details:
Xcode shows an uncaught exception during image processing:
terminating due to uncaught exception of type std::bad_alloc: std::bad_alloc
VTPixelTransferSession 420f sid 269 (2160.00 x 3840.00) [0.00 0.00 2160 3840]
rowbytes( 2160, 2160 ) Color( (null), 0x0, (null), (null), ITU_R_601_4 )
=> 24 sid 19 (2160.00 x 3840.00) [0.00 0.00 2160 3840] rowbytes( 6528 )
Color( 0x0, (null), (null), (null) )
This appears to be a memory allocation failure in VTPixelTransferSession during color space conversion. Has anyone else experienced similar crashes with CorePhotogrammetry on iOS 26, or found workarounds?
Topic:
Graphics & Games
SubTopic:
RealityKit
I'm trying to get video material to work on an imported 3D asset, and this asset is a USDC file. There's actually an example in this WWDC video from Apple. You can see it running on the flag in this airplane, but there are no examples of this, and there are no other examples on the internet. Does anybody know how to do this?
You can look at 10:34 in this video.
https://developer.apple.com/documentation/realitykit/videomaterial
I am using the latest version of the Game Center plugin for Unity and have noticed that my game will crash on launch when trying to authenticate.
I've tried this in an empty project with just the plugin and it still crashes with this exception.
GfxDevice: creating device client; threaded=1; jobified=0
Initializing Metal device caps: Apple A14 GPU
Initialize engine version: 2022.3.62f2 (7670c08855a9)
GameKitException: Code=-7 Domain=GKErrorDomain Description=The operation couldn’t be completed. (GKErrorDomain error -7.) (UnsupportedOperationForOSVersion)
at Apple.GameKit.DefaultNSErrorHandler.ThrowNSError (System.IntPtr nsErrorPtr) [0x00000] in <00000000000000000000000000000000>:0
Rethrow as TypeInitializationException: The type initializer for 'Apple.GameKit.GKGameActivity' threw an exception.
And the area in the native code that is triggering the crash is this inside the GKLocalPlayer_SetAuthenticateHandler function
`_onAuthenticate!(tid, _mostRecentAuthenticatePlayer!.passRetainedUnsafeMutablePointer());
I am using Unity 2022.3.62f2 and MacOS 15.6 with iOS 18.6.2 which based on the min specs for the plugin we should be within spec.
I have also included this message because I thought it might help too
`terminating due to uncaught exception of type Il2CppExceptionWrapper
Could not import Swift modules for translation unit: failed to get module "GameKitWrapper" from AST context:
error: 'GKErrorCodeExtension.h' file not found
in file included from :1:
error: could not build Objective-C module 'GameKitWrapper'
warning: Ignoring missing VFS file: /Users/james/Library/Developer/Xcode/DerivedData/GameKitWrapper-dzawbtxqdxdviiakfxmfunexppqv/Build/Intermediates.noindex/GameKitWrapper.build/Release-iphoneos/GameKitWrapper-bc72bd3638f4d2956cac9b00e84c1a7d-VFS-iphoneos/all-product-headers.yaml
This is the likely root cause for any subsequent compiler
errors.warning: Ignoring missing VFS file: /Users/bill/Library/Developer/Xcode/DerivedData/GameKitWrapper-dzawbtxqdxdviiakfxmfunexppqv/Build/Intermediates.noindex/GameKitWrapper.build/Release-iphoneos/GameKitWrapper iOS.build/unextended-module-overlay.yaml
This is the likely root cause for any subsequent compiler errors.warning: TypeSystemSwiftTypeRef::GetNumChildren: had to engage SwiftASTContext fallback for type $syyXCD
I've also attached the script that I am using for authentication, this script runs on the first scene.
GameCenterManager.cs