I am trying to load some PNG data with MTKTextureLoader newTextureWithData，but the result shows wrong at the alpha area. Here is the code. I have an image URL, after it downloads successfully, I try to use the data or UIImagePNGRepresentation (image), they all show wrong. UIImage *tempImg = [UIImage imageWithData:data]; CGImageRef cgRef = tempImg.CGImage; MTKTextureLoader *loader = [[MTKTextureLoader alloc] initWithDevice:device]; id<MTLTexture> temp1 = [loader newTextureWithData:data options:@{MTKTextureLoaderOptionSRGB: @(NO), MTKTextureLoaderOptionTextureUsage: @(MTLTextureUsageShaderRead), MTKTextureLoaderOptionTextureCPUCacheMode: @(MTLCPUCacheModeWriteCombined)} error:nil]; NSData *tempData = UIImagePNGRepresentation(tempImg); id<MTLTexture> temp2 = [loader newTextureWithData:tempData options:@{MTKTextureLoaderOptionSRGB: @(NO), MTKTextureLoaderOptionTextureUsage: @(MTLTextureUsageShaderRead), MTKTextureLoaderOptionTextureCPUCacheMode: @(MTLCPUCacheModeWriteCombined)} error:nil]; id<MTLTexture> temp3 = [loader newTextureWithCGImage:cgRef options:@{MTKTextureLoaderOptionSRGB: @(NO), MTKTextureLoaderOptionTextureUsage: @(MTLTextureUsageShaderRead), MTKTextureLoaderOptionTextureCPUCacheMode: @(MTLCPUCacheModeWriteCombined)} error:nil]; }] resume];

I have a photo editing app which uses a simple Metal Render to display CIFilter output images. It works just fine in Swift 5 but in Swift 6 it crashes on starting the Metal command buffer with an error in the Queue : com.Metal.CompletionQueueDispatch (serial). The crash is occurring before I can debug.. I changed the command buffer to report MTLCommandBufferDescriptorStatus errorOptions = .encoderExecutionStatus. No luck with getting insight into the source of the crash.. Likewise the error is happening before any of the usual Metal debug tools are enabled. The Metal render works just fine in Swift 5 and also works fine with almost all of the Swift Compiler Upcoming feature flags set to Yes. [The "Default Internal Imports" flag is still No. (the number of compile errors with this setting is absolutely scary! but that's another topic) Do you have any suggestions on debugging or ideas on why the Metal library is crashing in Swift 6??? Everything is current release versions and hardware.

Hello, I am using MTKView to display: camera preview & video playback. I am testing on iPhone 16. App crashes at a random moment whenever MTKView is rendering CIImage. MetalView: public enum MetalActionType { case image(CIImage) case buffer(CVPixelBuffer) } public struct MetalView: UIViewRepresentable { let mtkView = MTKView() public let actionPublisher: any Publisher<MetalActionType, Never> public func makeCoordinator() -> Coordinator { Coordinator(self) } public func makeUIView(context: UIViewRepresentableContext<MetalView>) -> MTKView { guard let metalDevice = MTLCreateSystemDefaultDevice() else { return mtkView } mtkView.device = metalDevice mtkView.framebufferOnly = false mtkView.clearColor = MTLClearColor(red: 0, green: 0, blue: 0, alpha: 0) mtkView.drawableSize = mtkView.frame.size mtkView.delegate = context.coordinator mtkView.isPaused = true mtkView.enableSetNeedsDisplay = true mtkView.preferredFramesPerSecond = 60 context.coordinator.ciContext = CIContext( mtlDevice: metalDevice, options: [.priorityRequestLow: true, .highQualityDownsample: false]) context.coordinator.metalCommandQueue = metalDevice.makeCommandQueue() context.coordinator.actionSubscriber = actionPublisher.sink { type in switch type { case .buffer(let pixelBuffer): context.coordinator.updateCIImage(pixelBuffer) break case .image(let image): context.coordinator.updateCIImage(image) break } } return mtkView } public func updateUIView(_ nsView: MTKView, context: UIViewRepresentableContext<MetalView>) { } public class Coordinator: NSObject, MTKViewDelegate { var parent: MetalView var metalCommandQueue: MTLCommandQueue! var ciContext: CIContext! private var image: CIImage? { didSet { Task { @MainActor in self.parent.mtkView.setNeedsDisplay() //<--- call Draw method } } } var actionSubscriber: (any Combine.Cancellable)? private let operationQueue = OperationQueue() init(_ parent: MetalView) { self.parent = parent operationQueue.qualityOfService = .background super.init() } public func mtkView(_ view: MTKView, drawableSizeWillChange size: CGSize) { } public func draw(in view: MTKView) { guard let drawable = view.currentDrawable, let ciImage = image, let commandBuffer = metalCommandQueue.makeCommandBuffer(), let ci = ciContext else { return } //making sure nothing is nil, now we can add the current frame to the operationQueue for processing operationQueue.addOperation( MetalOperation( drawable: drawable, drawableSize: view.drawableSize, ciImage: ciImage, commandBuffer: commandBuffer, pixelFormat: view.colorPixelFormat, ciContext: ci)) } //consumed by Subscriber func updateCIImage(_ img: CIImage) { image = img } //consumed by Subscriber func updateCIImage(_ buffer: CVPixelBuffer) { image = CIImage(cvPixelBuffer: buffer) } } } now the MetalOperation class: private class MetalOperation: Operation, @unchecked Sendable { let drawable: CAMetalDrawable let drawableSize: CGSize let ciImage: CIImage let commandBuffer: MTLCommandBuffer let pixelFormat: MTLPixelFormat let ciContext: CIContext init( drawable: CAMetalDrawable, drawableSize: CGSize, ciImage: CIImage, commandBuffer: MTLCommandBuffer, pixelFormat: MTLPixelFormat, ciContext: CIContext ) { self.drawable = drawable self.drawableSize = drawableSize self.ciImage = ciImage self.commandBuffer = commandBuffer self.pixelFormat = pixelFormat self.ciContext = ciContext } override func main() { let width = Int(drawableSize.width) let height = Int(drawableSize.height) let ciWidth = Int(ciImage.extent.width) //<-- Thread 22: EXC_BAD_ACCESS (code=1, address=0x5e71f5490) A bad access to memory terminated the process. let ciHeight = Int(ciImage.extent.height) let destination = CIRenderDestination( width: width, height: height, pixelFormat: pixelFormat, commandBuffer: commandBuffer, mtlTextureProvider: { [self] () -> MTLTexture in return drawable.texture }) let transform = CGAffineTransform( scaleX: CGFloat(width) / CGFloat(ciWidth), y: CGFloat(height) / CGFloat(ciHeight)) do { try ciContext.startTask(toClear: destination) try ciContext.startTask(toRender: ciImage.transformed(by: transform), to: destination) } catch { } commandBuffer.present(drawable) commandBuffer.commit() commandBuffer.waitUntilCompleted() } } Now I am no Metal expert, but I believe it's a very simple execution that shouldn't cause memory leak especially after we have already checked for whether CIImage is nil or not. I have also tried running this code without OperationQueue and also tried with @autoreleasepool but none of them has solved this problem. Am I missing something?

my app use mtkview to render video, but [MTKView initwithFrame:device] takes 2-3s in some some 2019 macbook pro, system macos 15.0.1. how can I do?

I am trying to extract some built-in and custom render passes from SceneKit, so that I can pass them into a metal pipeline and do some additional work with them. I have a metal viewport, and have instantiated a SCNRenderer so that I can render a SCNScene using SceneKit to a texture as part of my metal draw pass. This works as expected. Now I want to output multiple textures from the SceneKit render, not just the final color. I want to extract Depth, Normal, Lighting, Colour and a custom SCNTechnique for world position. I can easily use a SCNTechnique to render one of these to the color output, but it's not clear how I would render multiple passes in one render call. Is there some way to pass a writeable buffer/texture to a SCNTechnique, so that I can populate it in my SCNTechnique shader at render time with the output from the pass? Similar to how one would bind a buffer for a metal shader. SCNTechnique obfuscates things, so it's not clear how to proceed. Does anyone have any ideas?

I have a very basic usdz file from this repo I call loadTextures() after loading the usdz via MDLAsset. Inspecting the MDLTexture object I can tell it is assigning a colorspace of linear rgb instead of srgb although the image file in the usdz is srgb. This causes the textures to ultimately render as over saturated. In the code I later convert the MDLTexture to MTLTexture via MTKTextureLoader but if I set the srgb option it seems to ignore it. This significantly impacts the usefulness of Model I/O if it can't load a simple usdz texture correctly. Am I missing something? Thanks!

I'm writing a swift app that uses metal to render textures to the main view. I currently use a NSViewRepresentable to place a MTKView into the window and a MTKViewDelegate to perform the metal operations. It's running well and I see my metal view being updated. However, when I close the window (either through the user clicking the close button or by programatically using the appropriate @Environment(\.dismissWindow) private var dismissWindow) and then reopen the window, I no longer receive calls to MTKViewDelegate draw(in mtkView: MTView). If I manually call the MTKView::draw() function my view updates it's content as expected, so it seems to be still be correctly setup / alive. As best as I can tell the CVDisplayLink created by MTKView is no longer active (or at least that's my understanding of how the MTKView::draw() function is called). I've setup the MTKView like this let mtkView = MTKView() mtkView.delegate = context.coordinator // My custom delegate mtkView.device = context.coordinator.device // The default metal device mtkView.preferredFramesPerSecond = 60 mtkView.enableSetNeedsDisplay = false mtkView.isPaused = false which I was hoping would call the draw function at 60fps while the view is visible. I've also verified the values don't change while running. Does anyone have any ideas on how I could restart the CVDisplayLink or anyother methods to avoid this problem?? Cheers Jack

The Problem When transitioning between view controllers that each have their own MTKView but share a Metal renderer backend, we run into delegate ownership conflicts. Only one MTKView can successfully render at a time, since setting the delegate on one view requires removing it from the other, leading to paused views during transitions. For my app, I need to display the same visuals across multiple views and have them all render correctly. Current Implementation Approach I've created a container object that manages the MTKView and its relationship with the shared renderer: class RenderContainer { let metalView: MTKView private let renderer: MetalRenderer func startRendering() { metalView.delegate = renderer metalView.isPaused = false } func stopRendering() { metalView.isPaused = true metalView.delegate = nil } } View controllers manage the rendering lifecycle in their view appearance methods: override func viewWillAppear(_ animated: Bool) { super.viewWillAppear(animated) renderContainer.startRendering() } override func viewWillDisappear(_ animated: Bool) { super.viewWillDisappear(animated) renderContainer.stopRendering() } Observations & Issues During view controller transitions, one MTKView must stop rendering before the other can start. Also there is no guarantee that the old view will stop rendering before the new one starts, with the current API design. This creates a visual "pop" during animated transitions Setting isPaused = true helps prevent unnecessary render calls but doesn't solve the core delegate ownership problem The shared renderer maintains its state but can only output to one view at a time Questions What's the recommended approach for handling MTKView delegate ownership during animated transitions? Are there ways to maintain visual continuity without complex view hierarchies? Should I consider alternative architectures for sharing the Metal content between views? Any insights for this scenario would be appreciated.

I want to implement the ability to apply Lightroom Preset (.xmp file) to an image in my app, but am running into difficulties. How can I configure things like color grading, curve, etc. in Swift?

I have multiple CAMetalLayers that I render content to and noticed that the graphics overview HUD does not function properly when I have more than one CAMetalLayer. The values reported will be very strange. For example, FPS may report 999 or some large negative value. It the HUD simply not designed to work with multiple CAMetalLayers or MTKViews? When I disable all but one of my CAMetalLayers, the HUD works as expected.

Hi! How to define and call an inline function in Metal? Or simple function that will return some value. Case: inline uint index4D(constant _4D& shape, constant uint& n, constant uint& c, constant uint& h, constant uint& w) { return n * shape.C * shape.H * shape.W + c * shape.H * shape.W + h * shape.W + w; } When I call it in my kernel function I get No matching function for call error. Thx in advance.

Hi, A user sent us a crash report that indicates an error occurring just after loading the default Metal library of our app. Application Specific Information: Crashing on exception: *** -[__NSArrayM objectAtIndex:]: index 0 beyond bounds for empty array The report pointed me to these (simplified) lines of codes in the library setup: _vertexFunctions = [[NSMutableArray alloc] init]; _fragmentFunctions = [[NSMutableArray alloc] init]; id<MTLLibrary> library = [device newDefaultLibrary]; 2 vertex shaders and 5 fragment shaders are then loaded and stored in these two arrays using this method: -(BOOL) addShaderNamed:(NSString *)name library:(id<MTLLibrary>)library isFragment:(BOOL)isFragment { id shader = [library newFunctionWithName:name]; if (!shader) { ALOG(@"Error : Unable to find the shader named : “%@”", name); return NO; } [(isFragment ? _fragmentFunctions : _vertexFunctions) addObject:shader]; return YES; } As you can see, the arrays are not filled if the method fails... however, a few lines later, they are used without checking if they are really filled, and that causes the crash... But this coding error doesn't explain why no shader of a certain type (or both types) have been added to the array, meaning: why -newFunctionWithName: returned nil for all given names (since the implied array appears completely empty)? Clue This error has only be detected once by a user running the app on macOS 10.13 with a NVIDIA Web Driver instead of the default macOS graphic driver. Moreover, it wasn't possible to reproduce the problem on the same OS using the native macOS driver. So my question is: is it some known conflicts between NVIDIA drivers and the use of Metal libraries? Or does this case would require some specific options in the Metal implementation? Any help appreciated, thanks!

if you check the code here, https://developer.apple.com/documentation/compositorservices/interacting-with-virtual-content-blended-with-passthrough var body: some Scene { ImmersiveSpace(id: Self.id) { CompositorLayer(configuration: ContentStageConfiguration()) { layerRenderer in let pathCollection: PathCollection do { pathCollection = try PathCollection(layerRenderer: layerRenderer) } catch { fatalError("Failed to create path collection \(error)") } let tintRenderer: TintRenderer do { tintRenderer = try TintRenderer(layerRenderer: layerRenderer) } catch { fatalError("Failed to create tint renderer \(error)") } Task(priority: .high) { @RendererActor in Task { @MainActor in appModel.pathCollection = pathCollection appModel.tintRenderer = tintRenderer } let renderer = try await Renderer(layerRenderer, appModel, pathCollection, tintRenderer) try await renderer.renderLoop() Task { @MainActor in appModel.pathCollection = nil appModel.tintRenderer = nil } } layerRenderer.onSpatialEvent = { pathCollection.addEvents(eventCollection: $0) } } } .immersionStyle(selection: .constant(appModel.immersionStyle), in: .mixed, .full) .upperLimbVisibility(appModel.upperLimbVisibility) the only way it's dealing with the error is fatalError. And don't think I can throw anything or return anything else? Is there a way I can gracefully handle this and show a message box in UI? I was hoping I could somehow trigger a failure and have https://developer.apple.com/documentation/swiftui/openimmersivespaceaction return fail. but couldn't find a nice way to do so. Let me know if you have ideas.

I have been concentrating on developing the visionOS application. While I am currently quite familiar with RealityKit, CompositorServices has also captured my attention. I have not yet acquired knowledge of CompositorServices. Could you please clarify whether it is essential for me to learn CompositorServices? Additionally, I would appreciate it if you could provide insights into the advantages of RealityKit and CompositorServices.

Hey guys, is it possible to implement mirror like reflections like in this project: https://developer.apple.com/documentation/metal/metal_sample_code_library/rendering_reflections_in_real_time_using_ray_tracing for visionOS? Or is the hardware not prepared for Metal Raytracing? Thanks in advance

XCode 16 seems to have an issue with stitchable kernels in Core Image which gives build errors as stated in this question. As a workaround, I selected Metal 3.2 as Metal Language Revision in XCode project. It works on newer devices like iPhone 13 pro and above but metal texture creation fails on older devices like iPhone 11 pro. Is this a known issue and is there a workaround? I tried selecting Metal language revision to 2.4 but the same build errors occur as reported in this question. Here is the code where assertion failure happens on iPhone 11 Pro. let vertexShader = library.makeFunction(name: "vertexShaderPassthru") let fragmentShaderYUV = library.makeFunction(name: "fragmentShaderYUV") let pipelineDescriptorYUV = MTLRenderPipelineDescriptor() pipelineDescriptorYUV.rasterSampleCount = 1 pipelineDescriptorYUV.colorAttachments[0].pixelFormat = .bgra8Unorm pipelineDescriptorYUV.depthAttachmentPixelFormat = .invalid pipelineDescriptorYUV.vertexFunction = vertexShader pipelineDescriptorYUV.fragmentFunction = fragmentShaderYUV do { try pipelineStateYUV = metalDevice?.makeRenderPipelineState(descriptor: pipelineDescriptorYUV) } catch { assertionFailure("Failed creating a render state pipeline. Can't render the texture without one.") return }

My app is suddenly broken when I build it with XCode 16. It seems Core Image kernels compilation is broken in XCode 16. Answers on StackOverflow seem to suggest we need to use a downgraded version of Core Image framework as a workaround, but I am not sure if there is a better solution out there. FYI, I am using [[ stitchable ]] kernels and I see projects having stitchable are the ones showing issue. air-lld: error: symbol(s) not found for target 'air64_v26-apple-ios17.0.0' metal: error: air-lld command failed with exit code 1 (use -v to see invocation) Showing Recent Messages /Users/Username/Camera4S-Swift/air-lld:1:1: ignoring file '/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS.sdk/System/Library/Frameworks/CoreImage.framework/CoreImage.metallib', file AIR version (2.7) is bigger than the one of the target being linked (2.6)

I use xcode16 and swiftUI for programming on a macos15 system. There is a problem. When I render a picture through mtkview, it is normal when displayed on a regular view. However, when the view is displayed through the .sheet method, the image cannot be displayed. There is no error message from xcode. import Foundation import MetalKit import SwiftUI struct CIImageDisplayView: NSViewRepresentable { typealias NSViewType = MTKView var ciImage: CIImage init(ciImage: CIImage) { self.ciImage = ciImage } func makeNSView(context: Context) -&gt; MTKView { let view = MTKView() view.delegate = context.coordinator view.preferredFramesPerSecond = 60 view.enableSetNeedsDisplay = true view.isPaused = true view.framebufferOnly = false if let defaultDevice = MTLCreateSystemDefaultDevice() { view.device = defaultDevice } view.delegate = context.coordinator return view } func updateNSView(_ nsView: MTKView, context: Context) { } func makeCoordinator() -&gt; RawDisplayRender { RawDisplayRender(ciImage: self.ciImage) } class RawDisplayRender: NSObject, MTKViewDelegate { // MARK: Metal resources var device: MTLDevice! var commandQueue: MTLCommandQueue! // MARK: Core Image resources var context: CIContext! var ciImage: CIImage init(ciImage: CIImage) { self.ciImage = ciImage self.device = MTLCreateSystemDefaultDevice() self.commandQueue = self.device.makeCommandQueue() self.context = CIContext(mtlDevice: self.device) } func mtkView(_ view: MTKView, drawableSizeWillChange size: CGSize) {} func draw(in view: MTKView) { guard let currentDrawable = view.currentDrawable, let commandBuffer = commandQueue.makeCommandBuffer() else { return } let dSize = view.drawableSize let drawImage = self.ciImage let destination = CIRenderDestination(width: Int(dSize.width), height: Int(dSize.height), pixelFormat: view.colorPixelFormat, commandBuffer: commandBuffer, mtlTextureProvider: { () -&gt; MTLTexture in return currentDrawable.texture }) _ = try? self.context.startTask(toClear: destination) _ = try? self.context.startTask(toRender: drawImage, from: drawImage.extent, to: destination, at: CGPoint(x: (dSize.width - drawImage.extent.width) / 2, y: 0)) commandBuffer.present(currentDrawable) commandBuffer.commit() } } } struct ShowCIImageView: View { let cii = CIImage.init(contentsOf: Bundle.main.url(forResource: "9-10", withExtension: "jpg")!)! var body: some View { CIImageDisplayView.init(ciImage: cii).frame(width: 500, height: 500).background(.red) } } struct ContentView: View { @State var showImage = false var body: some View { VStack { Image(systemName: "globe") .imageScale(.large) .foregroundStyle(.tint) Text("Hello, world!") ShowCIImageView() Button { showImage = true } label: { Text("showImage") } } .frame(width: 800, height: 800) .padding() .sheet(isPresented: $showImage) { ShowCIImageView() } } }

I'm using the Apple RoomPlan sdk to generate a .usdz file, which works fine, and gives me a 3D scan of my room. But when I try to use Model I/O's MDLAsset to convert that output into an .obj file, it comes out as a completely flat model shaped like a rectangle. Here is my Swift code: let destinationURL = destinationFolderURL.appending(path: "Room.usdz") do { try FileManager.default.createDirectory(at: destinationFolderURL, withIntermediateDirectories: true) try finalResults?.export(to: destinationURL, exportOptions: .model) let newUsdz = destinationURL; let asset = MDLAsset(url: newUsdz); let obj = destinationFolderURL.appending(path: "Room.obj") try asset.export(to: obj) } Not sure what's wrong here. According to MDLAsset documentation, .obj is a supported format and exporting from .usdz to the other formats like .stl and .ply works fine and retains the original 3D shape. Some things I've tried: changing "exportOptions" to parametric, mesh, or model. simply changing the file extension of "destinationURL" (throws error)

specifically using the newer colorEffect, layerEffect, etc routes. the below does not seem to work. do i have to use the old MTK stuff? import SwiftUI import MetalKit struct HoloPreview: View { let startDate = Date() @State private var noiseTexture: MTLTexture? var body: some View { TimelineView(.animation) { context in RoundedRectangle(cornerRadius: 20) .fill(Color.red) .layerEffect(ShaderLibrary.iridescentEffect( .float(startDate.timeIntervalSinceNow), .texture(noiseTexture) ), maxSampleOffset: .zero) } .onAppear { noiseTexture = loadTexture(named: "perlinNoiseMap") } } func loadTexture(named imageName: String) -> MTLTexture? { guard let device = MTLCreateSystemDefaultDevice(), let url = Bundle.main.url(forResource: imageName, withExtension: "png") else { return nil } let textureLoader = MTKTextureLoader(device: device) let texture = try? textureLoader.newTexture(URL: url, options: nil) return texture } } #Preview { HoloPreview() }