Hi!
I'd like to share a technical sample app, SKRenderer Demo.
This app demonstrates:
Setting up SKRenderer
Recording SpriteKit scenes to image sequences
Recording SpriteKit scenes to video using IOSurface and AVFoundation
Applying Core Image filters
Exploring SpriteKit's simulation timing and physics determinism
Use Case
Record SpriteKit simulations as video or images for sharing and creating content.
I explored several approaches, including the excellent view.texture(from:crop:) for live recording from SKView. The SKRenderer approach assumes recording happens asynchronously: you capture user interactions as commands during live interaction, then replay those commands through an offline render pass to generate the final output.
I hope this helps others working on replay systems, simulation capture, or SpriteKit projects in general!
Delve into the world of graphics and game development. Discuss creating stunning visuals, optimizing game mechanics, and share resources for game developers.
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We are developing a hybrid iOS app where Angular content is rendered inside a WKWebView, hosted by a native Swift application.
We use the GameController framework to detect whether an external Bluetooth keyboard is connected to an iPad. The following code is executed when the app enters the foreground and also when requested by the web layer:
func keyboardStatusHandler(){
let isKeyboardConnected = GCKeyboard.coalesced != nil
if(!isKeyboardConnected){
//sent status to Angular
} else {
//sent status to Angular
}
}
Crash details
We are seeing intermittent crashes on iPad with the following stack trace:
Crashed: GCDeviceSession.HID
0 libobjc.A.dylib 0x7db8 objc_retain_x8 + 16
1 libsystem_blocks.dylib 0xfb8 void HelperBase<ExtendedInline>::copyCapture<(HelperBase<ExtendedInline>::BlockCaptureKind)3>(unsigned int) + 48
2 libsystem_blocks.dylib 0xbc4 HelperBase<GenericInline>::copyBlock(Block_layout*, Block_layout*) + 108
3 libsystem_blocks.dylib 0xc94 _call_copy_helpers_excp + 60
4 libsystem_blocks.dylib 0xef8 _Block_copy + 412
5 libdispatch.dylib 0x1a70 _dispatch_Block_copy + 32
6 libdispatch.dylib 0x792c dispatch_async + 56
7 libdispatch.dylib 0x792c dispatch_channel_async + 56
8 GameController 0xea6dc -[GCKeyboardInput _handleKeyboardEvent:] + 324
9 GameController 0x22508 __53-[_GCKeyboardEventHIDAdapter initWithSource:service:]_block_invoke + 376
10 GameController 0x11d30 -[_GCHIDEventSubject publishHIDEvent:] + 268
11 GameController 0xb79cc __40-[_GCHIDEventUIKitClient initWithQueue:]_block_invoke_3 + 44
12 libdispatch.dylib 0x1b584 _dispatch_client_callout + 16
13 libdispatch.dylib 0x12088 _dispatch_async_and_wait_invoke_and_complete_recurse + 272
14 libdispatch.dylib 0x8448 _dispatch_async_and_wait_f + 108
15 GameController 0xb7984 __40-[_GCHIDEventUIKitClient initWithQueue:]_block_invoke_2 + 132
16 GameController 0xb746c __48-[__GCHIDEventUIKitClient _initWithApplication:]_block_invoke + 256
17 UIKitCore 0x11fd394 __61-[UIEventFetcher _setHIDGameControllerEventObserver:onQueue:]_block_invoke_3 + 40
18 libdispatch.dylib 0x1aac _dispatch_call_block_and_release + 32
19 libdispatch.dylib 0x1b584 _dispatch_client_callout + 16
20 libdispatch.dylib 0xa2d0 _dispatch_lane_serial_drain + 740
21 libdispatch.dylib 0xadac _dispatch_lane_invoke + 388
22 libdispatch.dylib 0x151dc _dispatch_root_queue_drain_deferred_wlh + 292
23 libdispatch.dylib 0x14a60 _dispatch_workloop_worker_thread + 540
24 libsystem_pthread.dylib 0xa0c _pthread_wqthread + 292
25 libsystem_pthread.dylib 0xaac start_wqthread + 8
Observed scenarios
Crash occurs when the app transitions from background to foreground
Crash also occurs when the Angular layer requests keyboard status, triggering the same code path
Questions
Has anyone encountered crashes related to GCKeyboard.coalesced or GCKeyboardInput like this?
Are there known issues with the GameController framework when querying keyboard state during app lifecycle transitions?
Is there a recommended or safer way to detect external keyboard connection status on iPad (especially when using WKWebView)?
Any insights, known platform issues, or suggested workarounds would be greatly appreciated.
Thanks!
After authenticating the user I'm loading my Game Center leaderboards like this:
let leaderboards = try await GKLeaderboard.loadLeaderboards(IDs: [leaderboardID])
This is working fine, but there are times when this just returns an empty array. When I encounter this situation, the array remains empty for several hours when retrying, but then at some point it suddenly starts working again.
Is this a known issue? Or am I hitting some kind of quota maybe (as I do it quite often while developing my game)?.
Edit: My leaderboards are grouped in sets if that makes any difference here.
Starting with iOS 18.0 beta 1, I've noticed that RealityKit frequently crashes in the simulator when an app launches and presents an ARView.
I was able to create a small sample app with repro steps that demonstrates the issue, and I've submitted feedback: FB16144085
I've included a crash log with the feedback.
If possible, I'd appreciate it if an Apple engineer could investigate and suggest a workaround. It's awkward to be restricted to the iOS 17 simulator, which does not exhibit this behavior.
Please let me know if there's anything I can do to help.
Thank you.
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)
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 am trying the simplest use of attachment in realityKit and get Contextual closure type @MainActor, @Sendable (inout RealityViewCameraContent) async -> void expects 1 argument, but 2 were used in closure body.
Also i get cannot find Attachment in scope
Hi,
Introducing Swift Concurrency to my Metal app has been a bit challenging as Swift Concurrency is limited by the cooperative thread pool.
GPU work is obviously not CPU bound and can block forward moving progress, especially when using waitUntilCompleted on the command buffer. For concurrent render work this has the potential of under utilizing the CPU and even creating dead locks.
My question is, what is the Metal's teams general recommendation when it comes to concurrency? It seems to me that Dispatch or OperationQueues are still the preferred way for Metal bound tasks in order to gain maximum performance?
To integrate with Swift Concurrency my idea is to use continuations that kick off render jobs via Dispatch or Queues? Would this be the best solution to bridge async tasks with Metal work?
Thanks!
When trying to play with friends Krazy Krownz doesn’t allow me to click multiplayer even though my Apple Game Center connected and my friends Apple game center connected as well. I even tried sending an invite from Apple Game Center to friends and Krazy Krownz doesn’t even show up on the list of available multiplayer games.
I’ve signed out and back in the same issue remain.
I’ve try to contact the game developer, but the website doesn’t work.
Topic:
Graphics & Games
SubTopic:
GameKit
I have a game built in Unreal Engine 5.6 which uses tilt motion controls to rotate an object. I've restricted the app to only run in portrait for iPhone, and everything works fine, however for iPad I've had a few issues relating to multitasking and I can't seem to solve it.
Forcing the app to portrait only still allows the app to run in landscape mode, but shows black bars either side of the game, and the axes for the motion controls are incorrect. X becomes Y and Y becomes X, and there's no way for my app to know which orientation it is because the container is still technically portrait.
Allowing my game to run in all orientations makes the whole app more presentable, it doesn't add black bars and the game is still functional and I'm able to map the controls correctly because the game knows it's landscape rather than portrait.
The problem with allowing my app to run in landscape mode is if multitasking is enabled on the ipad, you can resize the app to be portrait, and then I run into the same problem again where the game thinks it's portrait mode and all of the axes are wrong again.
I tried getting the true orientation of the device rather than the scene, but the game is intended to be played flat so instead of returning the orientation of the OS the orientation is FaceUp, which doesn't help.
I need to either disable multitasking or find a way of getting the orientation of the OS (not the scene or the device). I haven't found how to get the OS orientation so I've been trying to disable multitasking.
I've got Requires Fullscreen true and UIApplicationSupportsMultipleScreens false in my info.plist but my iPad still seems to allow the window to be resized in landscape view. Opening the IOS workspace of my project Requires Fullscreen is ticked but under that it says "Supports Multiple Windows" and the arrow button next to it takes my to my info.plist values, but no indication of how I can change it.
I'm using Unreal Engine 5.6 and Xcode 16.0. Xcode is old I know, but this version of unreal engine doesn't seem to support any newer.
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
Post can be removed.
My app is live but the leaderboards still aren’t updating. App was built with unreal engine 5 with blueprints. I have the leaderboard stat info entered into the node for write integer to leaderboard and a node for show platform specific leaderboard. The leaderboards are shown as live on app connect.
When I run the app, the Game Center login functions and the leaderboard interface launches as expected but it just lists a group of friends to invite. There are no scores listed and it says number of players 0 even though I have scored on two different devices and accounts. I have the Game Center entitlement added in Xcode. Not sure where else to look.
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
In a Unity game, if the assetBundle.Unloadinterface is called very frequently during normal gameplay, it can cause the game application's screen to freeze, although the background music continues to play normally. This issue only occurs on iPhone 16 and iPhone 17 models, with no problems on lower-version phones. How can this problem be resolved?
Hey there,
I tried to install GPTK again, since I had to reinstall the OS for irrelevant reasons. But every time I try to install the tool kit, it gives me theError: apple/apple/game-porting-toolkit 1.1 did not build error. Before that error occired, I had the Openssl error, which I fixed with the rbenv version of openssl. Is there any way to fix this error? Down bellow you'll find the full error message it gave me. The specs for my Mac are (if they are helpful in any way): M1 Pro MBP 14" with 16GB Ram and 512GB SSD.
Thanks!
``Error: apple/apple/game-porting-toolkit 1.1 did not build
Logs:
/Users/myuser/Library/Logs/Homebrew/game-porting-toolkit/00.options.out
/Users/myuser/Library/Logs/Homebrew/game-porting-toolkit/01.configure
/Users/myuser/Library/Logs/Homebrew/game-porting-toolkit/01.configure.cc
/Users/myuser/Library/Logs/Homebrew/game-porting-toolkit/wine64-build
If reporting this issue please do so at (not Homebrew/brew or Homebrew/homebrew-core):
https://github.com/apple/homebrew-apple/issues```
I think I really have tried everything and I did all according to official documentation to support game mode on iOS or iPadOS but it doesn't matter what I do it just doesn't get triggered. Funny enough it works during development when I install it via Xcode but as soon as it is live on the store and when I install it from there game mode doesn't get triggered anymore. What I have atm
I have added (even though it is deprecated)
<key>GCSupportsGameMode</key>
<true/>
I have set the (but it seems only supported for macOS)
<key>LSApplicationCategoryType</key>
<string>public.app-category.games</string>
I have added
<key>LSSupportsGameMode</key>
<true/>
It just doesn't work. Is there anything else what needs to be done? Should the flag LSSupportsGameMode not be enough normally?
The reason why this is so annoying is that my app is a real time streaming app and I want to profit from minimised background activities for smoother gameplay and more consistent frame rates like mentioned in the documentation.
Hi,
seems MSL is missing support for a clock() shader instruction available in other graphics APIs like Vulkan or OpenGL for example..
useful for counting cost in number of clock cycles of some code insider shader with much finer granularity than launching a micro kernel with same instructions and measuring cycles cost from CPU..
also useful for MoltenVK to support that extensions..
thanks..
Matchmaking rules
https://developer.apple.com/documentation/gamekit/matchmaking-rules?language=objc
AppStoreConnectApi rules
https://developer.apple.com/documentation/appstoreconnectapi/rules?language=objc
・Environment
Unity 6000.2.2f1
XCode 16.1
iOS 26
3 iPhones
・AppStoreConnectApi rules
"type": "gameCenterMatchmakingRuleSets",
"id": "f6a88caf-85db-42bf-xxxxxxxxxxxxxxxxxxxx",
"attributes": {
"referenceName": "co.mygame.RuleSets.GvERandom34",
"ruleLanguageVersion": 1,
"minPlayers": 3,
"maxPlayers": 4
},
"type": "gameCenterMatchmakingRules",
"id": "6afa68ce-4d2c-496f-xxxxxxxxxxxxxxxxxxxx",
"attributes": {
"referenceName": "GameVersion",
"description": "Check Game Version. GvERandom34",
"type": "COMPATIBLE",
"expression": "requests[0].properties.gameVersion == requests[1].properties.gameVersion",
"weight": null
},
"type": "gameCenterMatchmakingQueues",
"id": "7fb645ef-4eca-4510-xxxxxxxxxxxxxxxxxxxx",
"attributes": {
"referenceName": "co.mygame.que.GvERandom34",
"classicMatchmakingBundleIds": []
},
・Objective-C Execution code
queueName = "co.mygame.que.GvERandom34"
keyStr = "gameVersion "
valueStr = "1.0"
- (void)MatchQueueParamStr1Start:(NSString*)queueName keyStr:(NSString*)keyStr valueStr:(NSString*)valueStr
{
if (@available(iOS 17.2, tvOS 17.2, macOS 14.2, visionOS 1.1, *) == NO)
{
DBGLOG(@"MatchQueueParamStr1Start Not support.");
return;
}
self->_matchMakingFlag = YES;
self->_matchFinishFlag = NO;
self->_myMatch = nil;
GKMatchRequest *req = [[GKMatchRequest alloc] init];
if (@available(iOS 17.2, tvOS 17.2, macOS 14.2, visionOS 1.1, *))
{
req.queueName = queueName;
req.properties = @{keyStr: valueStr};
}
[[GKMatchmaker sharedMatchmaker] findMatchForRequest:req withCompletionHandler: ^(GKMatch *match, NSError *error)
{
if (error)
{
[self SetupErrorInfo:error descriptionText:@"findMatchForRequest"];
}
else if(match)
{
self->_myMatch = match;
self->_myMatch.delegate = self;
}
self->_matchMakingFlag = NO;
self->_matchFinishFlag = YES;
}];
}
・
I'm trying to match with three devices.
Matching doesn't work.
5 minutes later times out.
What's the problem?
I used xcode gpu capture to profile render pipeline's bandwidth of my game.Then i found depth buffer and stencil buffer use the same buffer whitch it's format is Depth32Float_Stencil8.
But why in a single pass of pipeline, this buffer was loaded twice, and the Load Attachment Size of Encoder Statistics was double.
Is there any bug with xcode gpu capture?Or the pass really loaded the buffer twice times?
Topic:
Graphics & Games
SubTopic:
Metal