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 }

I am trying to convert a ThreeJS project to Metal for the Vision Pro. The issue is ThreeJS doesn't do any color space conversion (when I output a color in a fragment shader and then read it using the digital color meter in SRGB mode I get the same value I inputed in the fragment shader) This is not the case when using metal. When setting up my LayerRenderer I set the colorFormat to rgba16Unorm since it is the only non srgb color format supported on the vision pro apps. However switching between bgra8Unorm_srgb and rgba16Unorm seems to have no affect. when I set up the renderPassDescriptor I use the drawable colorTexture renderPassDescriptor.colorAttachments[0].texture = drawable.colorTextures[0] and when printing its pixel format it seems to be passed from the configuration. If there is anyway to disable this behavior or perform an inverse function of such that I get the original value out from the shader, that would be appreciated.

Greetings! I have been battling with a bit of a tough issue. My use case is running a pixelwise regression model on a 2D array of images using CIImageProcessorKernel and a custom Metal Shader. It mostly works great, but the issue that arises is that if the regression calculation in Metal takes too long, an error occurs and the resulting output texture has strange artifacts, for example: The specific error is: Error excuting command buffer = Error Domain=MTLCommandBufferErrorDomain Code=1 "Internal Error (0000000e:Internal Error)" UserInfo={NSLocalizedDescription=Internal Error (0000000e:Internal Error), NSUnderlyingError=0x60000320ca20 {Error Domain=IOGPUCommandQueueErrorDomain Code=14 "(null)"}} (com.apple.CoreImage) There are multiple levels of concurrency: Swift Concurrency calling the Core Image code (which shouldn't have an impact) and of course the Metal command buffer. Is there anyway to ensure the compute command encoder can complete its work? Here is the full implementation of my CIImageProcessorKernel subclass: class ParametricKernel: CIImageProcessorKernel { static let device = MTLCreateSystemDefaultDevice()! override class var outputFormat: CIFormat { return .BGRA8 } override class func formatForInput(at input: Int32) -> CIFormat { return .BGRA8 } override class func process(with inputs: [CIImageProcessorInput]?, arguments: [String : Any]?, output: CIImageProcessorOutput) throws { guard let commandBuffer = output.metalCommandBuffer, let images = arguments?["images"] as? [CGImage], let mask = arguments?["mask"] as? CGImage, let fillTime = arguments?["fillTime"] as? CGFloat, let betaLimit = arguments?["betaLimit"] as? CGFloat, let alphaLimit = arguments?["alphaLimit"] as? CGFloat, let errorScaling = arguments?["errorScaling"] as? CGFloat, let timing = arguments?["timing"], let TTRThreshold = arguments?["ttrthreshold"] as? CGFloat, let input = inputs?.first, let sourceTexture = input.metalTexture, let destinationTexture = output.metalTexture else { return } guard let kernelFunction = device.makeDefaultLibrary()?.makeFunction(name: "parametric") else { return } guard let commandEncoder = commandBuffer.makeComputeCommandEncoder() else { return } let imagesTexture = Texture.textureFromImages(images) let pipelineState = try device.makeComputePipelineState(function: kernelFunction) commandEncoder.setComputePipelineState(pipelineState) commandEncoder.setTexture(imagesTexture, index: 0) let maskTexture = Texture.textureFromImages([mask]) commandEncoder.setTexture(maskTexture, index: 1) commandEncoder.setTexture(destinationTexture, index: 2) var errorScalingFloat = Float(errorScaling) let errorBuffer = device.makeBuffer(bytes: &errorScalingFloat, length: MemoryLayout<Float>.size, options: []) commandEncoder.setBuffer(errorBuffer, offset: 0, index: 1) // Other buffers omitted.... let threadsPerThreadgroup = MTLSizeMake(16, 16, 1) let width = Int(ceil(Float(sourceTexture.width) / Float(threadsPerThreadgroup.width))) let height = Int(ceil(Float(sourceTexture.height) / Float(threadsPerThreadgroup.height))) let threadGroupCount = MTLSizeMake(width, height, 1) commandEncoder.dispatchThreadgroups(threadGroupCount, threadsPerThreadgroup: threadsPerThreadgroup) commandEncoder.endEncoding() } }

The Metal feature set tables specifies that beginning with the Apple4 family, the "Maximum threads per threadgroup" is 1024. Given that a single threadgroup is guaranteed to be run on the same GPU shader core, it means that a shader core of any new Apple GPU must be capable of running at least 1024/32 = 32 warps in parallel. From the WWDC session "Scale compute workloads across Apple GPUs (6:17)": For relatively complex kernels, 1K to 2K concurrent threads per shader core is considered a very good occupancy. The cited sentence suggests that a single shader core is capable of running at least 2K (I assume this is meant to be 2048) threads in parallel, so 2048/32 = 64 warps running in parallel. However, I am curious what is the maximum theoretical amount of warps running in parallel on a single shader core (it sounds like it is more than 64). The WWDC session mentions 2K to be only "very good" occupancy. How many threads would be "the best possible" occupancy?

Our app encountered the following error: Execution of the command buffer was aborted due to an error during execution. Ignored (for causing prior/excessive GPU errors) (00000004:kIOGPUCommandBufferCallbackErrorSubmissionsIgnored)

How many 32-bit variables can I use concurrently in a single thread of a Metal compute kernel without worrying about the variables getting spilled into the device memory? Alternatively: how many 32-bit registers does a single thread have available for itself? Let's say that each thread of my compute kernel needs to store and work with its own array of N float variables, where N can be 128, 256, 512 or more. To achieve maximum possible performance, I do not want to the local thread variables to get spilled into the slow device memory. I want all N variables to be stored "on-chip", in the thread memory space. To make my question more concrete, let's say there is an array thread float localArray[N]. Assuming an unrealistic hypothetical scenario where localArray is the only variable in the whole kernel, what is the maximum value of N for which no portion of localArray would get spilled into the device memory? I searched in the Metal feature set tables, but I could not find any details.

We have a production Metal app with a complex multithreaded Metal pipeline. When everything is operating smoothly, it works great. Even when extremely overloaded, it does not crash for days at a time. This isn't good enough for our users. Unfortunately, when I have zero visibility into id, I have no way of knowing when metal is "done" with an id. When overloaded, stale metal render passes need to be 'aborted', which results in metal callbacks not being called. for example, these callbacks may not be called after an aborted pass: id<MTLCommandBuffer> m_cmdbuf; [m_cmdbuf addScheduledHandler:^(id <MTLCommandBuffer> cb) { cpr->scheduled = MachAbsoluteTime(); }]; [m_cmdbuf addCompletedHandler:^(id <MTLCommandBuffer> cb) { cpr->completed = MachAbsoluteTime(); }]; For the moment, our workaround is a system which waits a few seconds after we "think" a rendering pass should be done with all its (aborted) resources before releasing buffers. This is not ideal, to say the least. So, in summary, my question is, it would be nice to be able to 'query' an id to know when metal is done with it, so that we know that its safe to release it along with our own internal resources. Is there any such (undocumented) mechanism? I have exhaustively read all existing Metal documentation many times. An idea that I've been toying with... it would be nice to have something akin to Zombie detection running all the time for id only. In OpenGL, it was OK to use a released texture... you may display a bad frame, but not CRASH!. Is there any similar option for id?

We have been having a mysterious crash in our media server app that I've never seen before. After fixing a number of other rare thread safety crashes relating to Metal buffers, this rare crash happens inside a Metal com.Metal.CompletionQueueDispatch? I have no clue what is happening here. It looks to me like Metal is specifically calling abort() for some reason. All of the other threads in the crash log appear to be in a normal state. Thread 70 Crashed:: updateAllMedia Dispatch queue: com.Metal.CompletionQueueDispatch 0 libsystem_kernel.dylib 0x1af572d38 __pthread_kill + 8 1 libsystem_pthread.dylib 0x1af5a7ee0 pthread_kill + 288 2 libsystem_c.dylib 0x1af4e2330 abort + 168 3 libc++abi.dylib 0x1af562b18 abort_message + 132 4 libc++abi.dylib 0x1af552a3c demangling_terminate_handler() + 312 5 libobjc.A.dylib 0x1af4481c8 _objc_terminate() + 160 6 libc++abi.dylib 0x1af561eb4 std::__terminate(void (*)()) + 20 7 libc++abi.dylib 0x1af561e50 std::terminate() + 64 8 libdispatch.dylib 0x1af3e4288 _dispatch_client_callout4 + 40 9 libdispatch.dylib 0x1af40053c _dispatch_mach_msg_invoke + 464 10 libdispatch.dylib 0x1af3eb784 _dispatch_lane_serial_drain + 376 11 libdispatch.dylib 0x1af40125c _dispatch_mach_invoke + 456 12 libdispatch.dylib 0x1af3eb784 _dispatch_lane_serial_drain + 376 13 libdispatch.dylib 0x1af3ec438 _dispatch_lane_invoke + 444 14 libdispatch.dylib 0x1af3eb784 _dispatch_lane_serial_drain + 376 15 libdispatch.dylib 0x1af3ec404 _dispatch_lane_invoke + 392 16 libdispatch.dylib 0x1af3f6c98 _dispatch_workloop_worker_thread + 648 17 libsystem_pthread.dylib 0x1af5a4360 _pthread_wqthread + 288 18 libsystem_pthread.dylib 0x1af5a3080 start_wqthread + 8 Note that the thread name "updateAllMedia" is a misnomer because this thread appears to be a general Metal dispatch queue. I wish there was a debugging option in Metal that called "setThreadName" to name its internal threads.

VisionOS 2 beta 5 ，unity text shader errors

I have a test application that draws a large number of simple textured polygons (sprites). Setting CAMetalLayer's displaySyncEnabled to FALSE will cause load on InterruptEventSourceBridge thread in kernel_task. (In this case, nanosleep is used to adjust the amount of METAL commands per unit time so that they are approximately the same) This appears to be a drawing-related thread, but there is no overhead when displaySyncEnabled is TRUE. What are these differences? A specific application is the SDL test program, SDL/test/testsprite.c. https://github.com/libsdl-org/SDL/issues/10475

I have a test application that draws a large number of simple textured polygons (sprites). Setting CAMetalLayer's displaySyncEnabled to FALSE will cause load on InterruptEventSourceBridge thread in kernel_task. In this case, nanosleep() is used to adjust the amount of METAL commands per unit time so that they are approximately the same. This appears to be a drawing-related thread, but there is no overhead when displaySyncEnabled is TRUE. What are these differences? A specific application is the SDL test program, SDL/test/testsprite.c. https://github.com/libsdl-org/SDL/issues/10475

Why do I get this error almost immediately on starting my rendering pass? Multiline BlockQuote. 2024-05-29 20:02:22.744035-0500 RoomPlanExampleApp[491:10341] [] <<<< AVPointCloudData >>>> Fig assert: "_dataBuffer" at bail (AVPointCloudData.m:217) - (err=0) 2024-05-29 20:02:22.744455-0500 RoomPlanExampleApp[491:10341] [] <<<< AVPointCloudData >>>> Fig assert: "_dataBuffer" at bail (AVPointCloudData.m:217) - (err=0) 2024-05-29 20:05:54.079981-0500 RoomPlanExampleApp[491:10025] [CAMetalLayer nextDrawable] returning nil because allocation failed. 2024-05-29 20:05:54.080144-0500 RoomPlanExampleApp[491:10341] [] <<<< AVPointCloudData >>>> Fig assert: "_dataBuffer" at bail (AVPointCloudData.m:217) - (err=0)

I use quad_sum to optimize the lighting grid and shadow filter performance. Based on Metal Feature Set Tables, Apple Family 4 should support quad group operations like quad_sum and quad_max. However, on the iPhone X and iPhone 8, during creating pipeline states, we have the following error output: Encountered unlowered function call to air.quad_sum.f32. It works perfectly for iPhone 11 and higher versions. Should I improve my feature-checking logic from Apple Family 4 to Apple Family 5, or do I have other options to fix this unexpected behavior?

Is there new API for generating Indirect Commands for the Metal Shader Converter? Is there any example project? I currently use a shader to copy indirect commands. Is there a way to do that with the new Shader Converter pipeline?

I am trying to work out how to enable the Metal HUD on iOS for App Store games? I am aware you can go into Developer settings and enable it… but it only appears for some games like HADES or TestFlight apps. I know the HUD appears for sideloaded games too. With sideloadly, I’ve sideloaded GRID Autosport and Myst - per screenshots. But it’s a very time consuming process, on demand resources usually don’t download… and I’m not sure if its legal. I tried using Xcode and Attach to Process for a game like Resident Evil 7 or just anything… but it doesn’t work. I’ve tried restoring a backup and editing the .GlobalPreferences.plist and info.plist file with “MetalForceHudEnabled Boolean Yes”, in a new row… but nothing. any ideas?

I'm trying to create heat maps for a variety of functions of two variables. My first implementation didn't use Metal and was far too slow so now I'm looking into doing it with Metal. I managed to get a very simple example running but I can't figure out how to pass different functions to the fragment shader. Here's the example: in ContentView.swift: struct ContentView: View { var body: some View { Rectangle() .aspectRatio(contentMode: .fit) .visualEffect { content, gp in let width = Shader.Argument.float(gp.size.width) let height = Shader.Argument.float(gp.size.height) return content.colorEffect( ShaderLibrary.heatMap(width, height) ) } } } in Shader.metal: #include <metal_stdlib> using namespace metal; constant float twoPi = 6.283185005187988; // input in [0,1], output in [0,1] float f(float x) { return (sin(twoPi * x) + 1) / 2; } // inputs in [0,1], output in [0,1] float g(float x, float y) { return f(x) * f(y); } [[ stitchable ]] half4 heatMap(float2 pos, half4 color, float width, float height) { float u = pos.x / width; float v = pos.y / height; float c = g(u, v); return half4(c/2, 1-c, c, 1); } As it is, it works great and is blazing fast... ...but the function I'm heat-mapping is hardcoded in the metal file. I'd like to be able to write different functions in Swift and pass them to the shader from within SwiftUI (ie, from the ContentView, by querying a model to get the function). I tried something like this in the metal file: // (u, v) in [0,1] x [0,1] // w = f(u, v) in [0,1] [[ stitchable ]] half4 heatMap( float2 pos, half4 color, float width, float height, float (*f) (float u, float v), half4 (*c) (float w) ) { float u = pos.x / width; float v = pos.y / height; float w = f(u, v); return c(w); } but I couldn't get Swift and C++ to work together to make sense of the function pointers and and now I'm stuck. Any help is greatly appreciated. Many thanks!

Hello As part of my app, I am using Metal shaders on CustomMaterials created and managed using RealityKit. Using the ECS approach, I have a Shader system that iterates through all my materials every frame and passes a SIMD4 of variables (that I can manage on the swift side) that can be interpreted and used every frame on the Metal side to influence elements of the shader. This does work as intended but is limited to just 4 variables when I need more for my use case. I've experimented with trying multiple simd4 or other approaches for passing these to metal and be useable but I haven't had very much luck. I was hoping for some recommendations on the best scalable approach. Swift: class ShaderSystem: System { static let query = EntityQuery(where: .has(ModelComponent.self)) private var startTime: Date required init(scene: Scene) { startTime = Date() } func update(context: SceneUpdateContext) { let audioLevel = AudioSessionManager.shared.audioLevel let elapsedTime = Float(Date().timeIntervalSince(startTime)) guard let sceneType = SceneManager.shared.currentScenes.keys.first else { return } let sceneTime = SceneComposer.shared.getSceneTime(for: sceneType) let multiplier = ControlManager.shared.getControlValue(parameterName: "elapsedTimeMultiplier") ?? 1.0 for entity in context.scene.performQuery(Self.query) { guard var modelComponent = entity.components[ModelComponent.self] as? ModelComponent else { continue } modelComponent.materials = modelComponent.materials.map { material in guard var customMaterial = material as? CustomMaterial else { return material } // Passing audioLevel, elapsedTime, sceneTime, and multiplier customMaterial.custom.value = SIMD4<Float>(audioLevel, elapsedTime, sceneTime, multiplier) return customMaterial } entity.components[ModelComponent.self] = modelComponent } } } metal: struct CustomMaterialUniforms { float4 custom; }; [[visible]] void fractalShader(realitykit::surface_parameters params) { auto uniforms = params.uniforms(); float4 customValues = uniforms.custom_parameter(); float audioLevel = customValues.x; .... Thank you for the assistance

Here is the test code run in a macOS app (MacOS 15 Beta3). If the excutable path does not contain Chinese character, every thing go as We expect. Otherwise(simply place excutable in a Chinese named directory) , the MTLLibrary We made by newLibraryWithSource: function contains no functions, We just got logs: "Library contains the following functions: {}" "Function 'squareKernel' not found." Note: macOS 14 works fine id<MTLDevice> device = MTLCreateSystemDefaultDevice(); if (!device) { NSLog(@"not support Metal."); } NSString *shaderSource = @ "#include <metal_stdlib>\n" "using namespace metal;\n" "kernel void squareKernel(device float* data [[buffer(0)]], uint gid [[thread_position_in_grid]]) {\n" " data[gid] *= data[gid];\n" "}"; MTLCompileOptions *options = [[MTLCompileOptions alloc] init]; options.languageVersion = MTLLanguageVersion2_0; NSError *error = nil; id<MTLLibrary> library = [device newLibraryWithSource:shaderSource options:options error:&error]; if (error) { NSLog(@"New MTLLibrary error: %@", error); } NSArray<NSString *> *functionNames = [library functionNames]; NSLog(@"Library contains the following functions: %@", functionNames); id<MTLFunction> computeShaderFunction = [library newFunctionWithName:@"squareKernel"]; if (computeShaderFunction) { NSLog(@"Found function 'squareKernel'."); NSError *pipelineError = nil; id<MTLComputePipelineState> pipelineState = [device newComputePipelineStateWithFunction:computeShaderFunction error:&pipelineError]; if (pipelineError) { NSLog(@"Create pipeline state error: %@", pipelineError); } NSLog(@"Create pipeline state succeed!"); } else { NSLog(@"Function 'squareKernel' not found."); }

I'm trying to create a MTLFXTemporalScaler as follows (this is adapted from the sample code): func updateTemporalScaler() { let desc = MTLFXTemporalScalerDescriptor() desc.inputWidth = renderTarget.renderSize.width desc.inputHeight = renderTarget.renderSize.height desc.outputWidth = renderTarget.windowSize.width desc.outputHeight = renderTarget.windowSize.height desc.colorTextureFormat = .bgra8Unorm desc.depthTextureFormat = .depth32Float desc.motionTextureFormat = .rg16Float desc.outputTextureFormat = .bgra8Unorm guard let temporalScaler = desc.makeTemporalScaler(device: device) else { fatalError("The temporal scaler effect is not usable!") } temporalScaler.motionVectorScaleX = Float(renderTarget.renderSize.width) temporalScaler.motionVectorScaleY = Float(renderTarget.renderSize.height) mfxTemporalScaler = temporalScaler } I'm getting the following error the 3rd time the code is called: /AppleInternal/Library/BuildRoots/91a344b1-f985-11ee-b563-fe8bc7981bff/Library/Caches/com.apple.xbs/Sources/MetalPerformanceShadersGraph/mpsgraph/MetalPerformanceShadersGraph/Runtimes/MPSRuntime/Operations/RegionOps/ANRegion.mm:855: failed assertion `ANE intermediate buffer handle not same!' When I copy the code out to a playground, it succeeds when called with the same sequence of descriptors. Does this seem like a bug with MTLFXTemporalScaler?

Unity 2022.3.33f1 For some reason modifying MeshRenderer material shader SetVectorArray doesn't work on IOS, but it works on android and windows builds!! I was working on Fog Of War, where I used SimpleFOW by Revision3 it's very simple FOW shader where it manipulates the alpha based on UVs vertices. This is the FogOfWarShaderControl.cs script using System.Collections; using System.Collections.Generic; using UnityEngine; namespace SimpleFOW { [RequireComponent(typeof(MeshRenderer))] public class FogOfWarShaderControl : MonoBehaviour { public static FogOfWarShaderControl Instance { get; private set; } [Header("Maximum amount of revealing points")] [SerializeField] private uint maximumPoints = 512; [Header("Game Camera")] [SerializeField] private Camera mainCamera; private List<Vector4> points = new List<Vector4>(); private Vector2 meshSize, meshExtents; private Vector4[] sendBuffer; private MeshRenderer meshRenderer; private void Awake() { Instance = this; Init(); } // Initialize required variables public void Init() { meshRenderer = GetComponent<MeshRenderer>(); meshExtents = meshRenderer.bounds.extents; meshSize = meshRenderer.bounds.size; points = new List<Vector4>(); sendBuffer = new Vector4[maximumPoints]; } // Transform world point to UV coordinate of FOW mesh public Vector2 WorldPointToMeshUV(Vector2 wp) { Vector2 toRet = Vector2.zero; toRet.x = (transform.position.x - wp.x + meshExtents.x) / meshSize.x; toRet.y = (transform.position.y - wp.y + meshExtents.y) / meshSize.y; return toRet; } // Show or hide FOW public void SetEnabled(bool on) { meshRenderer.enabled = on; } // Add revealing point to FOW renderer if amount of points is lower than MAX_POINTS public void AddPoint(Vector2 worldPoint) { if (points.Count < maximumPoints) { points.Add(WorldPointToMeshUV(worldPoint)); } } // Remove FOW revealing point public void RemovePoint(Vector2 worldPoint) { if (worldPoint == new Vector2(0, 0)) { return; } if (points.Contains(WorldPointToMeshUV(worldPoint))) { points.Remove(WorldPointToMeshUV(worldPoint)); } } // Send any change to revealing point list to shader for rendering public void SendPoints() { points.ToArray().CopyTo(sendBuffer, 0); meshRenderer.material.SetVectorArray("_PointArray", sendBuffer); meshRenderer.material.SetInt("_PointCount", points.Count); } // Send new range value to shader public void SendRange(float range) { meshRenderer.material.SetFloat("_RadarRange", range); } // Send new scale value to shader public void SendScale(float scale) { meshRenderer.material.SetFloat("_Scale", scale); } } } And this is the FogOfWar.shader Shader "Revision3/FogOfWar" { Properties { _MainTex ("Texture", 2D) = "black" {} _PointCount("Point count", Range(0,512)) = 0 _Scale("Scale", Float) = 1.0 _RadarRange("Range", Float) = .5 _MaxAlpha("Maximum Alpha", Float) = 1.0 } SubShader { Tags { "RenderType"="Transparent" "Queue"="Transparent" } LOD 100 ZWrite Off Blend SrcAlpha OneMinusSrcAlpha Pass { CGPROGRAM #pragma vertex vert #pragma fragment frag // make fog work #pragma multi_compile_fog #include "UnityCG.cginc" struct appdata { float4 vertex : POSITION; float2 uv : TEXCOORD0; }; struct v2f { float2 uv : TEXCOORD0; UNITY_FOG_COORDS(1) float4 vertex : SV_POSITION; }; sampler2D _MainTex; float4 _MainTex_ST; float _RadarRange; uint _PointCount; float _Scale; float _MaxAlpha; float2 _PointArray[512]; v2f vert (appdata v) { v2f o; o.vertex = UnityObjectToClipPos(v.vertex); o.uv = TRANSFORM_TEX(v.uv, _MainTex); return o; } float getDistance(float2 pa[512], float2 uv) { float cdist = 99999.0; for (uint i = 0; i < _PointCount; i++) { cdist = min(cdist, distance(pa[i]*_Scale, uv)); } return cdist; } fixed4 frag (v2f i) : SV_Target { // sample the texture fixed4 col = tex2D(_MainTex, i.uv); i.uv *= _Scale; if (_PointCount > 0) col.w = min(_MaxAlpha, max(0.0f, getDistance(_PointArray, i.uv) - _RadarRange)); else col.w = _MaxAlpha; return col; } ENDCG } } } Now I create a gameobject called FogOfWar as follows And then in Unit.cs script and Building.cs script I add the following logic private Vector3 lastPos; private void Update() { if (lastPos != transform.position) { FogOfWarShaderControl.Instance.RemovePoint(lastPos); FogOfWarShaderControl.Instance.AddPoint(transform.position); lastPos = transform.position; FogOfWarShaderControl.Instance.SendPoints(); } } Now this gives me the effect of FOW as follows on IOS where the result should be as follows on other devices I don't know what causes this to happen only on IOS devices. The logic works fine on android/windows/Linux/editor but not IOS devices. So why metal API doesn't support shader set vector array?!