Hi Apple, In VisionOS, for real-time streaming of large 3D scenes, I plan to create Metal buffers and textures in multiple threads and then use a compute shader on the main thread to copy the Metal resources into RealityKit, minimizing main thread usage. Given that most of RealityKit's default APIs require execution on the main actor (main thread), it is not ideal for streaming data. Is this approach the best way to handle streaming data and real-time rendering? Thank you very much.

I have this drawing app that I have been working on for the past few years when I have free time. I recently rebuilt the app in Metal to build out other brushes and improve performance, need to render 10000s of lines in realtime. I’m running into this issue trying to create a uniform opacity per path. I have a solution but do not love it - as this is a realtime app and the solution could have some bottlenecks. If I just generate a triangle strip from touch points and do my best to smooth, resample, and handle miters I will always get some overlaps. See: To create a uniform opacity I render to an offscreen texture with blending disabled. I then pre-multiply the color and draw that texture to a composite texture with blending on (I do this per path). This works but gets tricky when you introduce a textured brush, the edges of the texture in the frag shader cut out the line. Pasted Graphic 1.png Solution: I discard below a threshold fragment float4 fragment_line(VertexOut in [[stage_in]], texture2d<float> texture [[ texture(0) ]]) { constexpr sampler s(coord::normalized, address::mirrored_repeat, filter::linear); float2 texCoord = in.texCoord; float4 texColor = texture.sample(s, texCoord); if (texColor.a < 0.01) discard_fragment(); // may be slow (from what I read) return in.color * texColor; } Better but still not perfect. Question: I'm looking for better ways to create a uniform opacity per path. I tried .max blending but that will cause no blending of other paths. Any tips, ideas, much appreciated. If this is too detailed of a question just achieve.

I'm currently converting my game from SceneKit to RealityKit. What's the easiest way to run an animation in which every frame I want to run custom code, similar to SCNAction.customAction which accepts a callback that is called repeatedly until the action completes?

Create the QRCode CIFilter<CIBlendWithMask> *f = CIFilter.QRCodeGenerator; f.message = [@"Message" dataUsingEncoding:NSASCIIStringEncoding]; f.correctionLevel = @"Q"; // increase level CIImage *qrcode = f.outputImage; Overlay the icon CIImage *icon = [CIImage imageWithURL:url]; CGAffineTransform *t = CGAffineTransformMakeTranslation( (qrcode.extent.width-icon.extent.width)/2.0, (qrcode.extent.height-icon.extent.height)/2.0); icon = [icon imageByApplyingTransform:t]; qrcode = [icon imageByCompositingOver:qrcode]; Round off the corners static dispatch_once_t onceToken; static CIWarpKernel *k; dispatch_once(&onceToken, ^ { k = [CIWarpKernel kernelWithFunctionName:name fromMetalLibraryData:metalLibData() error:nil]; }); CGRect iExtent = image.extent; qrcode = [k applyWithExtent:qrcode.extent roiCallback:^CGRect(int i, CGRect r) { return CGRectInset(r, -radius, -radius); } inputImage:qrcode arguments:@[[CIVector vectorWithCGRect:qrcode.extent], @(radius)]]; …and this code for the kernel should go in a separate .ci.metal source file: float2 bend_corners (float4 extent, float s, destination dest) { float2 p, dc = dest.coord(); float ratio = 1.0; // Round lower left corner p = float2(extent.x+s,extent.y+s); if (dc.x < p.x && dc.y < p.y) { float2 d = abs(dc - p); ratio = min(d.x,d.y)/max(d.x,d.y); ratio = sqrt(1.0 + ratio*ratio); return (dc - p)*ratio + p; } // Round lower right corner p = float2(extent.x+extent.z-s, extent.y+s); if (dc.x > p.x && dc.y < p.y) { float2 d = abs(dc - p); ratio = min(d.x,d.y)/max(d.x,d.y); ratio = sqrt(1.0 + ratio*ratio); return (dc - p)*ratio + p; } // Round upper left corner p = float2(extent.x+s,extent.y+extent.w-s); if (dc.x < p.x && dc.y > p.y) { float2 d = abs(dc - p); ratio = min(d.x,d.y)/max(d.x,d.y); ratio = sqrt(1.0 + ratio*ratio); return (dc - p)*ratio + p; } // Round upper right corner p = float2(extent.x+extent.z-s, extent.y+extent.w-s); if (dc.x > p.x && dc.y > p.y) { float2 d = abs(dc - p); ratio = min(d.x,d.y)/max(d.x,d.y); ratio = sqrt(1.0 + ratio*ratio); return (dc - p)*ratio + p; } return dc; }

I am trying to implement a ChacterControllerComponent using the following URL. https://developer.apple.com/documentation/realitykit/charactercontrollercomponent I have written sample code, but PhysicsSimulationEvents.WillSimulate is not executed and nothing happens. import SwiftUI import RealityKit import RealityKitContent struct ImmersiveView: View { let gravity: SIMD3<Float> = [0, -50, 0] let jumpSpeed: Float = 10 enum PlayerInput { case none, jump } @State private var testCharacter: Entity = Entity() @State private var myPlayerInput = PlayerInput.none var body: some View { RealityView { content in // Add the initial RealityKit content if let immersiveContentEntity = try? await Entity(named: "Immersive", in: realityKitContentBundle) { content.add(immersiveContentEntity) testCharacter = immersiveContentEntity.findEntity(named: "Capsule")! testCharacter.components.set(CharacterControllerComponent()) let _ = content.subscribe(to: PhysicsSimulationEvents.WillSimulate.self, on: testCharacter) { event in print("subscribe run") let deltaTime: Float = Float(event.deltaTime) var velocity: SIMD3<Float> = .zero var isOnGround: Bool = false // RealityKit automatically adds `CharacterControllerStateComponent` after moving the character for the first time. if let ccState = testCharacter.components[CharacterControllerStateComponent.self] { velocity = ccState.velocity isOnGround = ccState.isOnGround } if !isOnGround { // Gravity is a force, so you need to accumulate it for each frame. velocity += gravity * deltaTime } else if myPlayerInput == .jump { // Set the character's velocity directly to launch it in the air when the player jumps. velocity.y = jumpSpeed } testCharacter.moveCharacter(by: velocity * deltaTime, deltaTime: deltaTime, relativeTo: nil) { event in print("playerEntity collided with \(event.hitEntity.name)") } } } } } } The scene is loaded from RCP. It is simple, just a capsule on a pedestal. Do I need a separate code to run testCharacter from this state?

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

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

In the Creating A 3D Application With Hydra Rendering tutorial on the Apple Developer website, on the last step where I execute this command: cmake -S ~/Users/macuser/CreatingA3DApplicationWithHydraRendering/ -B ~/Users/macuser/CreatingA3DApplicationWithHydraRendering/ I keep getting an error: CMake Error at CMakeLists.txt:5 (include): include could not find requested file: /Users/macuser/USDInstall/bin/pxrConfig.cmake I've tried to follow the instructions as mentioned in the README.md file included in the project files at least 5 times as well as moving the pxrConfig.cmake file around and copying it in different folders, then executed the command and was still unsuccessful into generating the proper file expected to compile and render the HydraPlayer renderer. How do I get cmake to generate the Xcode file to create the HydraPlayer renderer?

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!

Hello! I'm a developer working on a plugin for the Elgato Stream Deck, called GPU Metrics. The plugin currently only works on Windows but I'd like to bring it to macOS. However, based on forum posts I've read (and StackOverflow) there isn't a very clear path to query GPU metrics like usage, temperature, used GPU memory, and power consumption. There are some tools out there that do similar things, but I wanted to see what would be the recommendation from Apple's engineering team to get this data via a public API. Requirements: Access GPU utilization, temperature, memory usage, power usage C/C++ based API for querying the metrics so I can expose the data to JavaScript via Node Addon No need to compatibile with Intel-based Macs, as Apple silicon will be fine for now Plugin GitHub Thank you! Noah

TLDR; I can't get QueueName to work with matchmaking a turn-based match in Unity using matchmaking rules. Long version: I'm using the apple unity plugin found here: https://github.com/apple/unityplugins/blob/main/plug-ins/Apple.GameKit/Apple.GameKit_Unity/Assets/Apple.GameKit/Documentation~/Apple.GameKit.md I have created a Queue, RuleSet and a simple Rule to match players by following these docs tightly: https://developer.apple.com/documentation/gamekit/finding-players-using-matchmaking-rules. Here is the single rule I have that drives matchmaking: { "data" : { "type" : "gameCenterMatchmakingRules", "id" : "[hiddden-rule-id]", "attributes" : { "referenceName" : "ComplimentaryFactionPreference", "description" : "default desc", "type" : "MATCH", "expression" : "requests[0].properties.preference != requests[1].properties.preference", "weight" : null }, "links" : { "self" : "https://api.appstoreconnect.apple.com/v1/gameCenterMatchmakingRules/[hidden-rule-id]" } }, "links" : { "self" : "https://api.appstoreconnect.apple.com/v1/gameCenterMatchmakingRules" } } which belongs to a rule set which belongs to a queue. I have verified these are setup and linked via the App Store Connect API. Additionally, when I tested queue-based matchmaking without a queue established, I got an error in Unity. Now, with this, I do not. However there is a problem when I attempt to use the queue for matchmaking. I have the basic C# function here: public override void StartSearch(NSMutableDictionary<NSString, NSObject> properties) { if (searching) return; base.StartSearch(properties); //Establish matchmaking requests _matchRequest = GKMatchRequest.Init(); _matchRequest.QueueName = _PreferencesToQueue(GetSerializedPreferences()); _matchRequest.Properties = properties; _matchRequest.MaxPlayers = PLAYERS_COUNT; _matchRequest.MinPlayers = PLAYERS_COUNT; _matchTask = GKTurnBasedMatch.Find(_matchRequest); } The _PreferencesToQueue(GetSerializedPreferences()); returns the exact name of the queue I added my ruleset to. After this function is called, I poll the task generated from the .Find(...) function. Every time I run this function, a new match is created almost instantly. No two players are ever added to the same match. Further, I'm running two built game instances, one on a mac and another on an ipad and when I simultaneously test, I am unable to join games this way. Can someone help me debug why I cannot seem to match make when using a queue based approach?

Hello everyone and thank you for you're time! I got an issue with uploading several icons to testflight. I'm using Game Maker Studio as my engine for the game. This is the error that I'm getting, even when I try to use the old icons for the game, that worked in the past. I tried to transform the icons, using this site "https://makeappicon.com/", but I still got the same validation error. Can you help me fixing the issue - thank you so much!

Dear colleagues, when will you add the ability to manually adjust the display's color temperature? Everyone is familiar with the color rendering issue on the 17 series. Many complain about the display's yellowish tint. I'm one of those people, with a G9N panel, but I can't get whites right; there's a persistent yellow tint. TrueTone only solves this problem under cool, white lighting conditions. So, the display might work as intended, but how can I make it work consistently? If there were a way to manually adjust TrueTone, many users wouldn't be so upset when buying a new device, fearing the display would be yellow. I'd like users to be able to choose their preferred color, warm or cool, and have a scale to adjust it! This would solve the yellowish tint issue on 17 series displays! Thank you.

Hi. I'm a 3D designer, using Blender for most of my work. The most recent Blender conference discussed utilizing the Open Shading Language (OSL) in their latest versions, which allows designers to write custom shaders for their workflows. At the moment, only Nvidia Optix GPU's can utilize this language for rendering (from what I understand), but Blender developers stated they are waiting on other GPU manufacturers to implement this feature as well. I'm not sure if there are any licensing issues here, but would this be something Apple could implement in Metal to make their hardware more attractive to the 3D design community? Any help or knowledge on this topic would be greatly appreciated.

Updated my app to include turn-based matches. Beta testing through FlightTest and all was well between iOS 18.x and 26.2 devices. One beta tester upgraded to 26.2 during beta testing and now when the MatchMaker VC is opened, it does not show existing matches. Worse, he can create new matches and play his turn, but the new match won't even show up in MMVC, even after opponent takes turn. My app has been reviewed and is ready for release, but I'd like to know how to solve this before I release. He has tried re-installing the app, including an updated FlightTest version that is the same as the about-to-be-released reviewed version.

I am trying to create a simple portal like that in RealityKit, but using metal instead of RealityKit. Has anyone been able to create a window or portal like thing to show a skybox outside in mixed Reality?

In my turn-based game, I receive GKListener event receivedTurnEventForMatch and decode the match.matchData. On occasion, the matchData is clearly stale and is from the previous turn. If I call the MatchMaker ViewController up and select that same match, the data is not stale, so it's not a matter of not calling endTurn. I have tried both loadMatchWithID and loadMatchesWithCompletionHandler after receiving the receivedTurnEventForMatch, but the data is still stale. Advice?

I'm running into a persistent visual issue while deploying a floral corridor scene to Apple Vision Pro using Unity 6.0 with URP and Metal. The issue only appears on the Vision Pro device — everything looks fine in the Unity Editor. Issue Description When the frame rate drops to around 60–70 FPS, noticeable distortion artifacts appear around the edges of foliage models. It seems like the background meshes (behind the plants) get warped and leak through the edges of the foliage. Although this is most visible around the leaves, even solid objects like standard URP wall or box models show distorted edges when the issue occurs. All the foliage uses Opaque or Alpha Clipping materials. Things I've Tried Changing the foliage materials to Transparent mode —distortion around edges disappears, but using Transparent for a large number of foliage assets is not ideal for performance or sorting complexity. Reducing the number of foliage objects — with only a few plants in the scene and the frame rate staying around 100 FPS, the distortion disappears. However, this isn’t a practical solution for a full environment. Possible Cause? I came across this note in the Unity documentation: "Ensure depth-buffer for each pixel is non-zero - on visionOS, the depth buffer is used for reprojection. To ensure visual effects like skyboxes and shaders are displayed beautifully, ensure that some value is written to the depth for each pixel." Could this be related to the issue? Is it possible that Alpha Clipping with low pixel coverage leads to some pixels not writing to the depth buffer, which then causes problems during Vision Pro’s reprojection or foveated rendering? However, even when I disable Alpha Clipping entirely, the distortion issue still persists, so it may not be solely caused by clipping itself. Project Setup Unity 6.0 (URP) Depth Texture: Enable Using Metal as the graphics backend Running on real Vision Pro hardware (not simulator) Any advice on how to avoid these distortion issues on Vision Pro would be greatly appreciated. Thanks!

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?

Hello, Could someone post code that shows how to implement GCVirtualController to move a box around the screen? I've been poking around with GCVirtualController and gotten as far as having the D-pad and A B buttons appear on the display. But how do I make it do anything?