After following the instructions here: https://developer.apple.com/metal/cpp/ I attempted building my project and Xcode presented several errors. In essence it's complaining about some redeclarations in the Metal-CPP headers. NSBundle.hpp and NSError.hpp are included in the metal-cpp/foundation directory from the metal-cpp download. Any help in getting these issues resolved is appreciated. Thanks!

I notice some metal-cpp classes have static funtion like static URL* fileURLWithPath(const class String* pPath); static class ComputePassDescriptor* computePassDescriptor(); static class AccelerationStructurePassDescriptor* accelerationStructurePassDescriptor(); which return a new object. these classes also provide 'alloc' and 'init' function to create object by default. for object created by 'alloc' and 'init', I use something like NS::Shaderd_Ptr or call release directly to free memory. Because 'alloc' and 'init' not explicit call on these static function. I wonder how to correctly free object created by these static function? did they managed by autorelease pool?

I'm implementing optimized matmul on metal: https://github.com/crynux-ai/metal-matmul/blob/main/metal/1_shared_mem.metal I notice that performance is significantly different with different threadgroup memory set in [computeEncoder setThreadgroupMemoryLength] All other lines are exactly same, the only difference is this parameter. Matmul performance is roughly 250 GFLops if I set 32768 (max bytes allowed on this M1 Max), but 400 GFLops if I set 8192. Why does this happen? How can I optimize it?

The game physics work as expected using GTPK 2.0 using Crossover 24 or Whisky. However, using GPTK 2.1 with Crossover 25, the player and camera physics misbehave. See https://www.reddit.com/r/WWEGames/comments/1jx9mph/the_siamese_elbow/ and https://www.reddit.com/r/WWEGames/comments/1jx9ow4/camera_glitch/ Full video also linked in the Reddit post. I have also submitted this bug via the feedback assistant.

Hello, Thank you for attending today’s Metal & game technologies group lab at WWDC25! We were delighted to answer many questions from developers and energized by the community engagement. We hope you enjoyed it and welcome your feedback. We invite you to carry on the conversation here, particularly if your question appeared in Slido and we were unable to answer it during the lab. If your question received feedback let us know if you need clarification. You may want to ask your question again in a different lab e.g. visionOS tomorrow. (We realize that this can be confusing when frameworks interoperate) We have a lot to learn from each other so let’s get to Q&A and make the best of WWDC25! 😃 Looking forward to your questions posted in new threads.

Hi, What's the best way to handle drastic changes in scene charateristics with the new MTLFXTemporalDenoisedScaler? Let's say a visible object of the scene radically changes its material properties. I can modify the albedo and roughness textures consequently. But I suspect the history will be corrupted. Blending visual information between the new frame and the previous ones might be a nonsense. I guess the problem should be the same when objects appear or disappear instantly. Is the upsacler manage these events for us (by lowering blending), or should we use the reactive or the denoise strength mask or something like that to handle them?

Im new in the Mac area but for sure not UE. Windows is a long process to packaging but it could be done. All the documentation for Epic and from the internet is basically non existent with exactly how to package a project within UE. I have Xcode installed which makes sense, agreed to terms and install for MacOS, I've been able to make a project for several weeks now and want to package for a test run for my friends to play on Windows. Now I just get this in the log: UATHelper: Packaging (Mac): ERROR: Failed to finalize the .app with Xcode. Check the log for more information UATHelper: Packaging (Mac): Trace written to file /Users/rileysleger/Library/Logs/Unreal Engine/LocalBuildLogs/UBA-ProjectNightTerror-Mac-Development.uba with size 12.6kb UATHelper: Packaging (Mac): Total time in Unreal Build Accelerator local executor: 8.12 seconds UATHelper: Packaging (Mac): Result: Failed (OtherCompilationError) UATHelper: Packaging (Mac): Total execution time: 9.71 seconds PackagingResults: Error: Failed to finalize the .app with Xcode. Check the log for more information UATHelper: Packaging (Mac): Took 9.77s to run dotnet, ExitCode=6 UATHelper: Packaging (Mac): UnrealBuildTool failed. See log for more details. (/Users/rileysleger/Library/Logs/Unreal Engine/LocalBuildLogs/UBA-ProjectNightTerror-Mac-Development.txt) UATHelper: Packaging (Mac): AutomationTool executed for 0h 0m 10s UATHelper: Packaging (Mac): AutomationTool exiting with ExitCode=6 (6) UATHelper: Packaging (Mac): RunUAT ERROR: AutomationTool was unable to run successfully. Exited with code: 6 PackagingResults: Error: AutomationTool was unable to run successfully. Exited with code: 6 PackagingResults: Error: Unknown Error This absolutely makes no sense to me. Anyone have ideas?

The sample code here, has code like: // Create a display link capable of being used with all active displays cvReturn = CVDisplayLinkCreateWithActiveCGDisplays(&_displayLink); But that function's doc says it's deprecated and to use NSView/NSWindow/NSScreen displayLink instead. That returns CADisplayLink, not CVDisplayLink. Also the documentation for that displayLink method is completely empty. I'm not sure if I'm supposed to add it to run loop, or what, after I get it. It would be nice to get an updated version of this sample project and/or have some documentation in NSView.displayLink

I am using Unreal Engine 5.6 on a MacBook Pro with an M3 chip and macOS 15.5. I’ve installed Xcode and accepted the license, but Unreal is not detecting the latest Metal Shader Standard (Metal v3.0). The maximum version Unreal sees is Metal v2.4, even though the hardware and OS should support Metal 3.0. I’ve also run sudo xcode-select -s /Applications/Xcode.app and accepted the license via Terminal. Is there anything in Xcode settings, SDK availability, or system permissions that could be preventing access to Metal 3.0 features?"

Hello! I'm developing a GPU (shader) language, where I aim to target multiple backends with a common frontend. I wanted to avoid having to round trip through Metal, and go straight to IR just like I have with SPIRV, in order to have a fast and efficient compilation process. I've been looking for a reference page where I can read about Metals IR, and as far as I'm aware, it exists, but I can't seem to find it anywhere. Furthermore, if such a reference is available, is there also a toolkit where I can run validation on the output IR, and perhaps even run optimizations, much like spv-tools for SPIRV? Any help would be appreciated! Thanks, Gustav

Our APP has integrated 3D function, in order to reduce the memory occupation of the APP in the background, we will uninstall the 3D after the APP enters the background. However, the uninstall also causes problems. When the uninstall process is executed in the background, the app will briefly trigger the background GPU rendering error warning with the error warning code: OGPUMetalError: Insufficient Permission (to submit GPU work from background) (00000006:kIOGPUCommandBufferCallbackErrorBackgroundExecutionNotPermitted) Execution of the command buffer was aborted due to an error during execution. Insufficient Permission (to submit GPU Work from background) (00000006: kIOGPUCommandBufferCallbackErrorBackgroundExecutionNotPermitted) excuse me this warning system will tighten APP permissions background?​ For example, limit or shorten the background survival time of the APP. In addition, will the background refresh function fail, resulting in the failure of Bluetooth Ibeacon activation?

We set the CVDisplayLink on macOS to 0 or 120, and get the following. This then clamps maximum refresh to 60Hz on the 120Hz ProMotion display on a MBP M2 Max laptop. How is this not fixed in 4 macOS releases? CoreVideo: currentVBLDelta returned 200000 for display 1 -- ignoring unreasonable value CoreVideo: [0x7fe2fb816020] Bad CurrentVBLDelta for display 1 is zero. defaulting to 60Hz.

Just wondering if anyone knows what it will take to hit greater than 60hz when targeting iPhone. If I set the preferredFramesPerSecond of an MTKView to 120, it works on the iPad, but on iPhone it never goes over 60hz, even with a simple hello triangle sample app... is this a limitation of targeting iPhone?

Can't seem to get the Metal HUD to display value range's (pre 26 Tahoe). The documented environment variable MTL_HUD_SHOW_VALUE_RANGE doesn't seem to work. https://developer.apple.com/documentation/xcode/monitoring-your-metal-apps-graphics-performance#Display-the-value-range-of-metrics Anyone having any luck?

I rewrote my graphics pipeline to use Load/Store better for clearing and don't care cases. All my tests pass, and in the Metal debugger, all the draw calls succeed. But when I present drawables (before [commandBuffer commit]) I only get a pink screen. I've tried everything I can think of: making sure the pixel formats are the same for the back buffer as my render targets, etc. But it's still pink. Could you point me in the right direction so I can fix this, or help describe why it's pink. That would be really helpful. Thank you, Brian Hapgood

It’s great that we’ll be able to use Metal custom renderers in passthrough mode on visionOS. https://developer.apple.com/wwdc24/10092 This is a lot of complicated set-up, however. It’s also unclear how occlusion and custom algorithms / raytracing will work in tandem with scene understanding. May we have a project template and/or sample? Preferably with the C api and not just swift. This would be much-appreciated and helpful to everyone who wants this set-up. I’d like to see the whole process. Thank you for introducing this feature!

Hello Everyone, within the renderEncoder?.drawIndexedPrimitives(type: .line…. function, I can't render all the lines of the object. I can see approx. 80%. Do you know what could be causing this? Other game engines, like those in C++, handle this just fine. import MetalKit class Renderer: NSObject, MTKViewDelegate { var parent: ContentView var metalDevice: MTLDevice! var metalCommandQueue: MTLCommandQueue! let allocator: MTKMeshBufferAllocator let pipelineState: MTLRenderPipelineState var scene: RenderScene let mesh: ObjMesh init(_ parent: ContentView) { self.parent = parent if let metalDevice = MTLCreateSystemDefaultDevice() { self.metalDevice = metalDevice } self.metalCommandQueue = metalDevice.makeCommandQueue() self.allocator = MTKMeshBufferAllocator(device: metalDevice) mesh = ObjMesh(device: metalDevice, allocator: allocator, filename: "cube") let pipelineDescriptor = MTLRenderPipelineDescriptor() let library = metalDevice.makeDefaultLibrary() pipelineDescriptor.vertexFunction = library?.makeFunction(name: "vertexShader") pipelineDescriptor.fragmentFunction = library?.makeFunction(name: "fragmentShader") pipelineDescriptor.colorAttachments[0].pixelFormat = .bgra8Unorm pipelineDescriptor.vertexDescriptor = MTKMetalVertexDescriptorFromModelIO(mesh.metalMesh.vertexDescriptor) do { try pipelineState = metalDevice.makeRenderPipelineState(descriptor: pipelineDescriptor) } catch { fatalError() } scene = RenderScene() super.init() } func mtkView(_ view: MTKView, drawableSizeWillChange size: CGSize) { } func draw(in view: MTKView) { //update scene.update() guard let drawable = view.currentDrawable else { return } let commandBuffer = metalCommandQueue.makeCommandBuffer() let renderPassDescriptor = view.currentRenderPassDescriptor renderPassDescriptor?.colorAttachments[0].clearColor = MTLClearColorMake(0, 0.5, 0.5, 1.0) renderPassDescriptor?.colorAttachments[0].loadAction = .clear renderPassDescriptor?.colorAttachments[0].storeAction = .store let renderEncoder = commandBuffer?.makeRenderCommandEncoder(descriptor: renderPassDescriptor!) renderEncoder?.setRenderPipelineState(pipelineState) var cameraData: CameraParameters = CameraParameters() cameraData.view = Matrix44.create_lookat( eye: scene.player.position, target: scene.player.position + scene.player.forwards, up: scene.player.up ) cameraData.projection = Matrix44.create_perspective_projection( fovy: 45, aspect: 800/600, near: 0.1, far: 10 ) renderEncoder?.setVertexBytes(&cameraData, length: MemoryLayout<CameraParameters>.stride, index: 2) renderEncoder?.setVertexBuffer(mesh.metalMesh.vertexBuffers[0].buffer, offset: 0, index: 0) for cube in scene.cubes { var model: matrix_float4x4 = Matrix44.create_from_rotation(eulers: cube.eulers) model = Matrix44.create_from_translation(translation: cube.position) * model renderEncoder?.setVertexBytes(&model, length: MemoryLayout<matrix_float4x4>.stride, index: 1) for submesh in mesh.metalMesh.submeshes { renderEncoder?.drawIndexedPrimitives( type: .line, indexCount: submesh.indexCount, indexType: submesh.indexType, indexBuffer: submesh.indexBuffer.buffer, indexBufferOffset: submesh.indexBuffer.offset ) } } renderEncoder?.endEncoding() commandBuffer?.present(drawable) commandBuffer?.commit() } } ==================== import MetalKit class ObjMesh { let modelIOMesh: MDLMesh let metalMesh: MTKMesh init(device: MTLDevice, allocator: MTKMeshBufferAllocator, filename: String) { guard let meshURL = Bundle.main.url(forResource: filename, withExtension: "obj") else { fatalError() } let vertexDescriptor = MTLVertexDescriptor() var offset: Int = 0 //position vertexDescriptor.attributes[0].format = .float3 vertexDescriptor.attributes[0].offset = offset vertexDescriptor.attributes[0].bufferIndex = 0 offset += MemoryLayout<SIMD3<Float>>.stride vertexDescriptor.layouts[0].stride = offset let meshDescriptor = MTKModelIOVertexDescriptorFromMetal(vertexDescriptor) (meshDescriptor.attributes[0] as! MDLVertexAttribute).name = MDLVertexAttributePosition let asset = MDLAsset(url: meshURL, vertexDescriptor: meshDescriptor, bufferAllocator: allocator) self.modelIOMesh = asset.childObjects(of: MDLMesh.self).first as! MDLMesh do { metalMesh = try MTKMesh(mesh: self.modelIOMesh, device: device) } catch { fatalError("couldn't load mesh") } } } =============== cube.obj Blender v2.91.0 OBJ File: '' www_blender_org mtllib piece.mtl o Cube_Cube.001 v -1.000000 1.000000 -1.000000 v -1.000000 1.000000 1.000000 v 1.000000 1.000000 -1.000000 v 1.000000 1.000000 1.000000 v -1.000000 -1.000000 -1.000000 v -1.000000 -1.000000 1.000000 v 1.000000 -1.000000 -1.000000 v 1.000000 -1.000000 1.000000 vt 0.375000 0.000000 vt 0.625000 0.000000 vt 0.625000 0.250000 vt 0.375000 0.250000 vt 0.625000 0.500000 vt 0.375000 0.500000 vt 0.625000 0.750000 vt 0.375000 0.750000 vt 0.625000 1.000000 vt 0.375000 1.000000 vt 0.125000 0.500000 vt 0.125000 0.750000 vt 0.875000 0.500000 vt 0.875000 0.750000 vn 0.0000 1.0000 0.0000 vn 1.0000 0.0000 0.0000 vn 0.0000 -1.0000 0.0000 vn -1.0000 0.0000 0.0000 vn 0.0000 0.0000 -1.0000 vn 0.0000 0.0000 1.0000 usemtl None s off f 1/1/1 2/2/1 4/3/1 3/4/1 f 3/4/2 4/3/2 8/5/2 7/6/2 f 7/6/3 8/5/3 6/7/3 5/8/3 f 5/8/4 6/7/4 2/9/4 1/10/4 f 3/11/5 7/6/5 5/8/5 1/12/5 f 8/5/6 4/13/6 2/14/6 6/7/6

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 have a bare-bones Metal app setup where I attach a CAMetalLayer to a window that inherits from a NSWindow with a custom delegate. Everything else is vanilla. I'm also using metal-cpp and metal shader converter. I'm running into a issue where the application runs fine in the beginning, but once I resize the window, it starts hitching. It turns out that [CAMetalLayer nextDrawable:] frequently (but not always) takes around a full second (plus or minus a few milliseconds) to return once drawableSize has been updated. I've tried setting allowsNextDrawableTimeout to false which doesn't work; it returns a valid drawable after a second instead of nil. Setting displaySyncEnabled to false reduces the likelihood of this happening to around 50% from 90%+ but does not eliminate it. Setting maximumDrawableCount to 2 or 3 does not seem to make a difference. By dumping the resource IDs of the returned textures I've noticed something interesting: Before resizing, the layer seems to shuffle between 2 textures or at least 2 resource IDs, but after resizing it starts to create new textures for each returned drawable. Occasionally it seems to reuse a previous resource ID, but it does not seem to have anything to do with whether the method returns quickly or not. Why does this happen, and how can I fix it? Should I create a new CAMetalLayer when resizing the window instead of updating drawableSize?

*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[NSBundle allFrameworks]: unrecognized selector sent to instance NS::Bundle* Bundle = NS::Bundle::mainBundle(); Bundle->allFrameworks(); call to allFrameworks() and allBundles() will throw exception, but other functions work well.