Hello, I want to create a painting app for iOS and I saw many examples use a CAShapeLayer to draw a UIBezierPath. As I understand CoreAnimation uses the GPU so I was wondering how is this implemented on the GPU? Or in other words, how would you do it with Metal or OpenGL? I can only think of continuously updating a texture in response to the user's drawing but that would be a very resource intensive operation... Thanks

In my app, I have an ARView that has cameraMode set to nonAR. I occasionally hide the ARView when it is not needed and reveal it again later. While the ARView is hidden, I'd like to pause the animation to save iPhone battery life. I'd also like to do this when I know that animation in my scene has paused and the contents of the view, although still visible, is static. This was possible using SceneKit, but I can't seem to find an equivalent way to do it using RealityKit. At least as of iOS 18, a hidden ARView with an empty scene appears to use approximately 30% of the CPU. How can I pause ARView so that it won't use the battery unnecessarily? Thank you for considering this question.

I'm testing on an iPhone 12 Pro, running iOS 17.5.1. Playing an HDR video with AVPlayer without explicitly specifying a pixel format (but specifying Metal Compatibility as below) gives buffers with the pixel format kCVPixelFormatType_Lossless_420YpCbCr10PackedBiPlanarVideoRange (&xv0). _videoOutput = [[AVPlayerItemVideoOutput alloc] initWithPixelBufferAttributes:@{ (NSString*)kCVPixelBufferMetalCompatibilityKey: @(YES) } I can't find an appropriate metal format to use for these buffers to access the data in a shader. Using MTLPixelFormatR16Unorm for the Y plane and MTLPixelFormatRG16Unorm for UV plane causes GPU command buffer aborts. My suspicion is that this compressed format isn't actually metal compatible due to the lack of padding bytes between pixels. Explicitly selecting kCVPixelFormatType_420YpCbCr10BiPlanarVideoRange (which uses 16 bits per pixel) for the AVPlayerItemVideoOutput works, but I'd ideally like to use the compressed formats if possible for the bandwidth savings. With SDR video, the pixel format is the lossless 8-bit one, and there are no problems binding those buffers to metal textures. I'm just looking for confirmation there's currently no appropriate metal format for binding the packed 10-bit planes. And if that's the case, is it a bug that AVPlayerVideoOutput uses this format despite requesting Metal compatibility?

I've got an iOS app that is using MetalKit to display raw video frames coming in from a network source. I read the pixel data in the packets into a single MTLTexture rows at a time, which is drawn into an MTKView each time a frame has been completely sent over the network. The app works, but only for several seconds (a seemingly random duration), before the MTKView seemingly freezes (while packets are still being received). Watching the debugger while my app was running revealed that the freezing of the display happened when there was a large spike in memory. Seeing the memory profile in Instruments revealed that the spike was related to a rapid creation of many IOSurfaces and IOAccelerators. Profiling CPU Usage shows that CAMetalLayerPrivateNextDrawableLocked is what happens during this rapid creation of surfaces. What does this function do? Being a complete newbie to iOS programming as a whole, I wonder if this issue comes from a misuse of the MetalKit library. Below is the code that I'm using to render the video frames themselves: class MTKViewController: UIViewController, MTKViewDelegate { /// Metal texture to be drawn whenever the view controller is asked to render its view. private var metalView: MTKView! private var device = MTLCreateSystemDefaultDevice() private var commandQueue: MTLCommandQueue? private var renderPipelineState: MTLRenderPipelineState? private var texture: MTLTexture? private var networkListener: NetworkListener! private var textureGenerator: TextureGenerator! override public func loadView() { super.loadView() assert(device != nil, "Failed creating a default system Metal device. Please, make sure Metal is available on your hardware.") initializeMetalView() initializeRenderPipelineState() networkListener = NetworkListener() textureGenerator = TextureGenerator(width: streamWidth, height: streamHeight, bytesPerPixel: 4, rowsPerPacket: 8, device: device!) networkListener.start(port: NWEndpoint.Port(8080)) networkListener.dataRecievedCallback = { data in self.textureGenerator.process(data: data) } textureGenerator.onTextureBuiltCallback = { texture in self.texture = texture self.draw(in: self.metalView) } commandQueue = device?.makeCommandQueue() } public func mtkView(_ view: MTKView, drawableSizeWillChange size: CGSize) { /// need implement? } public func draw(in view: MTKView) { guard let texture = texture, let _ = device else { return } let commandBuffer = commandQueue!.makeCommandBuffer()! guard let currentRenderPassDescriptor = metalView.currentRenderPassDescriptor, let currentDrawable = metalView.currentDrawable, let renderPipelineState = renderPipelineState else { return } currentRenderPassDescriptor.renderTargetWidth = streamWidth currentRenderPassDescriptor.renderTargetHeight = streamHeight let encoder = commandBuffer.makeRenderCommandEncoder(descriptor: currentRenderPassDescriptor)! encoder.pushDebugGroup("RenderFrame") encoder.setRenderPipelineState(renderPipelineState) encoder.setFragmentTexture(texture, index: 0) encoder.drawPrimitives(type: .triangleStrip, vertexStart: 0, vertexCount: 4, instanceCount: 1) encoder.popDebugGroup() encoder.endEncoding() commandBuffer.present(currentDrawable) commandBuffer.commit() } private func initializeMetalView() { metalView = MTKView(frame: CGRect(x: 0, y: 0, width: streamWidth, height: streamWidth), device: device) metalView.delegate = self metalView.framebufferOnly = true metalView.colorPixelFormat = .bgra8Unorm metalView.contentScaleFactor = UIScreen.main.scale metalView.autoresizingMask = [.flexibleWidth, .flexibleHeight] view.insertSubview(metalView, at: 0) } /// initializes render pipeline state with a default vertex function mapping texture to the view's frame and a simple fragment function returning texture pixel's value. private func initializeRenderPipelineState() { guard let device = device, let library = device.makeDefaultLibrary() else { return } let pipelineDescriptor = MTLRenderPipelineDescriptor() pipelineDescriptor.rasterSampleCount = 1 pipelineDescriptor.colorAttachments[0].pixelFormat = .bgra8Unorm pipelineDescriptor.depthAttachmentPixelFormat = .invalid /// Vertex function to map the texture to the view controller's view pipelineDescriptor.vertexFunction = library.makeFunction(name: "mapTexture") /// Fragment function to display texture's pixels in the area bounded by vertices of `mapTexture` shader pipelineDescriptor.fragmentFunction = library.makeFunction(name: "displayTexture") do { renderPipelineState = try device.makeRenderPipelineState(descriptor: pipelineDescriptor) } catch { assertionFailure("Failed creating a render state pipeline. Can't render the texture without one.") return } } } My question is simply: what gives?

I'm building an iOS/iPadOS app for iOS 18+ using the new RealityView in SwiftUI. (I may add visionOS, but I'm not focusing on it right now.) The 3D scene I'm rendering is fairly simple (just a few dozen vertices and a couple of textures), and I'd like to render it at 120fps on ProMotion devices if possible. I tried setting CADisableMinimumFrameDurationOnPhone to true in the info plist, but it had no effect. The frame rate in the GPU Report in Xcode stays capped at 60fps, and the gauge even tops out at 60. My question is kind of the opposite of this post, which asks how to limit the frame rate of a RealityView. I'm on Xcode 16 beta 5 on macOS Sonoma and iOS 18.0 beta 6 on my iPhone 15 Pro.

Hi, I'm trying to understand how I can get 3- or 4-channel per-vertex data into the Graph Editor. From my tests, it seems that: the "Geometric Property" node does not give access to 4-channel data, "Geometric Property (vector3)" does not give me access to custom properties besides the ones defined in MaterialX core the "Texture Coordinates" node has a vector4f mode (yay!), but according to MaterialX spec, texcoords must have 2 or 3 channels, and I can't get 4-channel data to show up there either. My assumption so far is that I must be missing some "magic" – for example, do the primvars in a file have to be in a specific order, independent of their names? Or do their names matter? (E.g. convention would be primars:st and primvars:st1 and so on) Unfortunately the forum doesn't allow me to attach any USDZ or ZIP files or GDrive links; if there's a way to share a test file I'm happy to do so!

I'm using RealityKit for a scene with many static and dynamic ModelEntitys simulating physics. When all the entities have simple collision generated from .generateCollisionShapes I don't see any issues, but for some entities I need much more complex and accurate collision. For this I've been using ShapeResource.generateStaticMesh with the mesh's data (2769 positions, 16272 face indices in this case), which works exactly as desired with a low entity count. However once there are 600+ dynamic entities introducing even one static entity with complex collision will reliably trigger a crash when colliding with one of the dynamic entities (not necessarily on first contact, but inevitably after multiple collisions). If I arbitrarily limit the number of entities to a max of around 500 it seems to prevent the issue from happening, though the likelihood seems to increase with the number of entities so there may be a low probability of it triggering even at 500 entities that I haven't hit while testing. If physx imposes some kind of entity or collision face/shape limit or something like that I'd at least like to know exactly what it is, but ideally there's a way to work around this. Right now my "fix" is just arbitrarily restricting the entity count in a way that limits what my app can do. The crash triggers inside 0x00000001a6790dfc in physx::PxcDiscreteNarrowPhasePCM(physx::PxcNpThreadContext&, physx::PxcNpWorkUnit const&, physx::Gu::Cache&, physx::PxsContactManagerOutput&) () which looks like this (crash line has an -> arrow at the bottom) CoreRE`physx::PxcDiscreteNarrowPhasePCM: ... 0x1a6790df0 <+668>: mov x1, x24 0x1a6790df4 <+672>: bl 0x1a67913d8 ; physx::PxcNpCacheStreamPair::reserve(unsigned int) 0x1a6790df8 <+676>: ldrb w8, [x23] -> 0x1a6790dfc <+680>: str w8, [x0, #0x20]

I wanted to try the new logging feature for Metal but could not get it to work. I modified the PerformingCalculationsOnAGPU example by adding os_log_default.log_debug("Hello thread: %d", index); to log the current thread id. But never saw any messages neither in the console nor in Xcode. I also added the -fmetal-enable-logging flag. I am running the Sequoia release candidate 15.0 (24A335) on M1 Max and Xcode 16.0 (16A242). What am I missing?

We’re experiencing an issue with wrong SceneKit hit testing results in iOS 17.2 compared with iOS 16.1 when using the either Metal or OpenGLES2 engines. Tapping on a 3D model to place a SCNNode // pointInScene: tapped point let hitResults = sceneView.hitTest(pointInScene, options: nil) return hitResults.first { $0.node.name?.compare("node_name") == .orderedSame }

What is the best way to display text over images - I'd like the image to fade to white underneath the text so that the text is easier to read since I have no control over the contents of the images. I thought about having a second label behind the actual label with the same text in a slightly larger font and white color. but I'd rather have it be a gradual fading of the image just under the text rather than what looks like 3D text. Any suggestions?

Hi, I'm creating a SF Symbols image like this: var img = UIImage(systemName: "x.circle" ,withConfiguration: symbolConfig)!.withTintColor(.red) In the debugger the image is really red. and I'm using this image to create a SKTexture: let shuffleTexture = SKTexture(image: img) The texture image is ALWAYS black and I have no idea how to change it's color. Nothing I've tried so far works. Any ideas how to solve this? Thank you! Best Regards, Frank

Hi everyone, I'm developing an ARKit app using RealityKit and encountering an issue where a video displayed on a 3D plane shows up as a pink screen instead of the actual video content. Here's a simplified version of my setup: func createVideoScreen(video: AVPlayerItem, canvasWidth: Float, canvasHeight: Float, aspectRatio: Float, fitsWidth: Bool = true) -> ModelEntity { let width = (fitsWidth) ? canvasWidth : canvasHeight * aspectRatio let height = (fitsWidth) ? canvasWidth * (1/aspectRatio) : canvasHeight let screenPlane = MeshResource.generatePlane(width: width, depth: height) let videoMaterial: Material = createVideoMaterial(videoItem: video) let videoScreenModel = ModelEntity(mesh: screenPlane, materials: [videoMaterial]) return videoScreenModel } func createVideoMaterial(videoItem: AVPlayerItem) -> VideoMaterial { let player = AVPlayer(playerItem: videoItem) let videoMaterial = VideoMaterial(avPlayer: player) player.play() return videoMaterial } Despite following the standard process, the video plane renders pink. Has anyone encountered this before, or does anyone know what might be causing it? Thanks in advance!

Summary: I’m working on a VisionOS project where I need to dynamically load a .bundle file containing RealityKit content from the app’s Application Support directory. The .bundle is saved to disk after being downloaded or retrieved as an On-Demand Resource (ODR). Sample project with the issue: Github repo. Play the target test-odr to use with the local bundle and have the crash. Overall problem: Setup: Add a .bundle named RealityKitContent_RealityKitContent.bundle to the app’s resources. This bundle contains a Reality file with two USDA,: “Immersive” and “Scene”. Save to Disk: save the bundle to the Application Support directory, ensuring that the file is correctly copied and saved. Load the Bundle: load the bundle from the saved URL using Bundle(url: bundleURL) to initialize the Bundle object. Load Entity from Bundle: load a specific entity (“Scene”) from the bundle. When trying to load the entity using let storedEntity = try await Entity(named: "Scene", in: bundle), the app crashes with an EXC_BREAKPOINT error. ContentsOf Method Issue: If I use the Entity.load(contentsOf:realityFileURL, withName: entityName) method, it always loads the first root entity found (in this case, “Immersive”) rather than “Scene”, even when specifying the entity name. This is why I want to use the Bundle to load entities by name more precisely. Issue: The crash consistently occurs on the Entity(named: "Scene", in: bundle) line. I have verified that the bundle exists and is accessible at the specified path and that it contains the expected .reality file with multiple entities (“Immersive” and “Scene”). The error code I get is EXC_BREAKPOINT (code=1, subcode=0x1d135d4d0). What I’ve Tried: • Ensured the bundle is properly saved and accessible. • Checked that the bundle is initialized correctly from the URL. • Tested loading the entity using the contentsOf method, which works fine but always loads the “Immersive” entity, ignoring the specified name. Hence, I want to use the Bundle-based approach to load multiple USDA entities selectively. Question: Has anyone faced a similar issue or knows why loading entities using Entity(named:in:) from a disk-based bundle causes this crash? Any advice on how to debug or resolve this, especially for managing multiple root entities in a .reality file, would be greatly appreciated.

I am having a difficult time to create particle systems in Reality Composer Pro (visionOS beta 3). They tend to start to flicker and all particles disappear and reappear in semi-random intervals. I can clearly see that happening with one effect that I put inside a small box consisting of 4 transparent walls that has a solid floor. When I change the view angle the particle system starts to flicker when viewed from below its emission height. I tried all combinations of particle rendering: billboard->free, additive etc and it does not change anything. I am using the default particle image. Any help appreciated

I have a legacy OpenGL fixed-pipeline app which has been ported from Windows (32-bit) to MacOS 64-bit. The problem is that if I have a scene with a non-positional light, everything works great. If I add a positional spotlight the two lights interact, and I get incorrect results. This problem does not occur on X86_64 Macs. It does occur when the app is X86_64 running under Rosetta or native ARM64. So it's either an Apple Silicon OpenGL driver behaviour my code is triggering, or something with the on-chip Apple Silicon graphics. Here is the "normal" case: the spotlight is to the right: Here, I have moved the spotlight down (Y = 1). Notice the black areas on the cube. That's incorrect. Now, I turn off the spotlight by commenting out the "makeALight" call for the spotlight (light 6). Now, the cube is evenly lit. Here is the test code I use to generate the lights. You will need to install glfw with brew to build it. main.cpp

Hi, I created a leaderboard in my application, and a method to record a new score: GKLeaderboard.loadLeaderboards(IDs: [leaderboardID]) { (leaderboards, error) in if let error = error { print("Error loading leaderboards: \(error.localizedDescription)") } guard let leaderboard = leaderboards?.first else { print("Leaderboard not found") return } leaderboard.submitScore(score, context: 0, player: self.localPlayer) { error in if let error = error { print("Error reporting score: \(error.localizedDescription)") } else { print("Score reported successfully!") } } } } When debuging, this method is correctly called and I have a success, so I tried to test it with an internal TestFlight release. The leaderboard is never updated. Is there a way to perform a test of a leaderboard before publishing the app? I have the same question for achievements: let achievement = GKAchievement(identifier: identifier) achievement.percentComplete = percentComplete GKAchievement.report([achievement]) { error in if let error = error { print("Error reporting achievement: \(error.localizedDescription)") } } } Thanks!

Hello! Bare with me here, as there is a lot to explain! I am working on implementing a Game Center high score leaderboard into my game. I have looked around for examples of how to properly implement this code, but have come up short on finding much material. Therefore, I have tried implementing it myself based off information I found on apples documentation. Long story short, I am getting success printed when I update my score, but no scores are actually being posted (or at-least no scores are showing up on the Game Center leaderboard when opened). Before I show the code, one thing I have questioned is the fact that this game is still in development. In AppStoreConnect, the status of the leaderboard is "Not Live". Does this affect scores being posted? Onto the code. I have created a GameCenter class which handles getting the leaderboards and posting scores to a specific leaderboard. I will post the code in whole, and will discuss below what is happening. PLEASE VIEW ATTACHED TEXT TO SEE THE GAMECENTER CLASS! GameCenter class - https://developer.apple.com/forums/content/attachment/0dd6dca8-8131-44c8-b928-77b3578bd970 In a different GameScene, once the game is over, I request to post a new high score to Game Center with this line of code: GameCenter.shared.submitScore(id: GameCenterLeaderboards.HighScore.rawValue) Now onto the logic of my code. For the longest time I struggled to figure out how to submit a score. I figured out that in Xcode 12, they deprecated a lot of functions that previously worked for me. Not is seems that we have to load all leaderboards (or the ones we want). That is the purpose behind the leaderboards private variable in the Game Center class. On the start up of the app, I call authenticate player. Once this callback is reached, I call loadLeaderboards which will load the leaderboards for each string id in an enum that I have elsewhere. Each of these leaderboards will be created as a Leaderboard object, and saved in the private leaderboard array. This is so I have access to these leaderboards later when I want to submit a score. Once the game is over, I am calling submitScore with the leaderboard id I want to post to. Right now, I only have a high score, but in the future I may add a parameter to this with the value so it works for other leaderboards as well. Therefore, no value is passed in since I am pulling from local storage which holds the high score. submitScore will get the leaderboard from the private leaderboard array that has the same id as the one passed in. Once I get the correct leaderboard, I submit a score to that leaderboard. Once the callback is hit, I receive the output "Successfully submitted score to leaderboard". This looks promising, except for the fact that no score is actually posted. At startup, I am calling updatePlayerHighScore, which is not complete - but for the purpose of my point, retrieves the high score of the player from the leaderboard and is printing it out to the console. It is printing out (0), meaning that no score was posted. The last thing I have questions about is the context when submitting a score. According to the documentation, this seems to just be metadata that GameCenter does not care about, but rather something the developer can use. Therefore, I think I can cross this off as causing the problem. I believe I implemented this correctly, but for some reason, nothing is posting to the leaderboard. This was ALOT, but I wanted to make sure I got all my thoughts down. Any help on why this is NOT posting would be awesome! Thanks so much! Mark

Hello, Asking the following as, I was unable to find answers via search on the forum and in the documentation: Invitations sent via iMessage seem to work correctly with my custom image ( GKMessageImage.png ) however, notifications sent to Game Center Friends via invites generated in Game Center do not include the custom image ( GKMessageImage.png ). Questions: Is this expected behavior? Is there a different way to customize the image in the notification? Note the Game Center notification includes the App name correctly. I also noted in the WWDC session in 2016 ( saw video recently ) that there was some mention of no longer adding friends via Game Center. Is that currently true? Thanks in advance.

Hello, I’m trying to run Age of Mythology Retold on my Mac using the Game Porting Toolkit. Unfortunately, the game crashes before it opens. Has anyone experienced something similar or have any suggestions on how to resolve it? Thank you!

I'm trying to ray-march an SDF inside a RealityKit surface shader. For the SDF primitive to correctly render with other primitives, the depth of the fragment needs to be set according to the ray-surface intersection point. Is there a way to do that within a RealityKit surface shader? It seems the only values I can set are within surface::surface_properties. If not, can an SDF still be rendered in RealityKit using ray-marching?