Hi, Reading the copyFromBuffer documentation states that on macOS, sourceOffset, destinationOffset, and size "needs to be a multiple of 4, but can be any value in iOS and tvOS". However, I have noticed that, at least on my M2 Max, this limitation does not seem to exist as there are no warnings and the copy works correctly regardless of the offset value. I'm curious to know if this is something that should still be avoided. Is the multiple of 4 limitation reserved for non Apple Silicon devices and that note can be ignored for Apple Silicon? I ask because I am a contributor to Metal.jl, and recently noticed that our tests pass even when copying using copyWithBuffer with offsets and sizes that are not multiples of 4. If that coul cause issues/correctness problems, we would need to fix that. Thank you. Christian

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?

Suppose I want to draw a red rectangle onto my render target using a compute shader. id<MTLComputeCommandEncoder> encoder = [commandBuffer computeCommandEncoder]; [encoder setComputePipelineState:pipelineState]; simd_ushort2 position = simd_make_ushort2(100, 100); simd_ushort2 size = simd_make_ushort2(50, 50); [encoder setBytes:&position length:sizeof(position) atIndex:0]; [encoder setTexture:drawable.texture atIndex:0]; [encoder dispatchThreads:MTLSizeMake(size.x, size.y, 1) threadsPerThreadgroup:MTLSizeMake(32, 32, 1)]; [encoder endEncoding]; #include <metal_stdlib> using namespace metal; kernel void Compute(ushort2 position_in_grid [[thread_position_in_grid]], constant ushort2 &position, texture2d<half, access::write> texture) { texture.write(half4(1, 0, 0, 1), position_in_grid + position); } This works just fine: Now, say for whatever reason I want to start using imageblocks in my compute kernel. First, I set the imageblock size on the CPU side: id<MTLComputeCommandEncoder> encoder = [commandBuffer computeCommandEncoder]; [encoder setComputePipelineState:pipelineState]; MTLSize threadgroupSize = MTLSizeMake(32, 32, 1); [encoder setImageblockWidth:threadgroupSize.width height:threadgroupSize.height]; simd_ushort2 position = simd_make_ushort2(100, 100); simd_ushort2 size = simd_make_ushort2(50, 50); [encoder setBytes:&position length:sizeof(position) atIndex:0]; [encoder setTexture:drawable.texture atIndex:0]; MTLSize gridSize = MTLSizeMake(size.x, size.y, 1); [encoder dispatchThreads:gridSize threadsPerThreadgroup:threadgroupSize]; And then I update the compute kernel to simply declare the imageblock – note I never actually read from or write to it: #include <metal_stdlib> using namespace metal; struct Foo { int foo; }; kernel void Compute(ushort2 position_in_grid [[thread_position_in_grid]], constant ushort2 &position, texture2d<half, access::write> texture, imageblock<Foo> imageblock) { texture.write(half4(1, 0, 0, 1), position_in_grid + position); } And now out of nowhere Metal’s shader validation starts complaining about mismatched texture usage flags: 2024-06-22 00:57:15.663132+1000 TextureUsage[80558:4539093] [GPUDebug] Texture usage flags mismatch executing kernel function "Compute" encoder: "1", dispatch: 0 2024-06-22 00:57:15.672004+1000 TextureUsage[80558:4539093] [GPUDebug] Texture usage flags mismatch executing kernel function "Compute" encoder: "1", dispatch: 0 2024-06-22 00:57:15.682422+1000 TextureUsage[80558:4539093] [GPUDebug] Texture usage flags mismatch executing kernel function "Compute" encoder: "1", dispatch: 0 2024-06-22 00:57:15.687587+1000 TextureUsage[80558:4539093] [GPUDebug] Texture usage flags mismatch executing kernel function "Compute" encoder: "1", dispatch: 0 2024-06-22 00:57:15.698106+1000 TextureUsage[80558:4539093] [GPUDebug] Texture usage flags mismatch executing kernel function "Compute" encoder: "1", dispatch: 0 The texture I’m writing to comes from a CAMetalDrawable whose associated CAMetalLayer has framebufferOnly set to NO. What am I missing?

got the above error when using PyTorch with diffusion model same error comes up in few games when running through D3D metal Anyone has any idea what this is about?

What is the info property of SwiftUI::Layer? I couldn't find any document or resource about it. It appears in SwiftUI::Layer's definition: struct Layer { metal::texture2d<half> tex; float2 info[5]; /// Samples the layer at `p`, in user-space coordinates, /// interpolating linearly between pixel values. Returns an RGBA /// pixel value, with color components premultipled by alpha (i.e. /// [R*A, G*A, B*A, A]), in the layer's working color space. half4 sample(float2 p) const { p = metal::fma(p.x, info[0], metal::fma(p.y, info[1], info[2])); p = metal::clamp(p, info[3], info[4]); return tex.sample(metal::sampler(metal::filter::linear), p); } };

I have a very simple Mac app with just a MTKView in it which shows a single color. I want to move the rendering code to C++. For this I created a C++ framework target which interoperates with the Swift code - main project target. I am trying to link metal-cpp library to the C++ framework target using these instructions. Approach described in this article works with simple C++ Mac console apps. But in my mixed Swift/C++ project Xcode cannot find Foundation/Foundation.hpp (and probably other headers) to include into the C++ header. I inserted metal-cpp folder into my project and added it to C++ target's header search paths, as written in the instructions.

The title is self-exploratory. I wasn't able to find the CAMetalDisplayLink on the most recent metal-cpp release (metal-cpp_macOS15_iOS18-beta). Are there any plans to include it in the next release?

Hi. I am developing an immersive application in Metal. The problem is that when the application starts for the first time, it shows two system windows: one related to the player's surrounding environment and the other to hand tracking permissions. The latter is the one in focus, and when I select the option to grant permissions, both windows disappear and the transition to the immersive view does not occur. I don't know how to handle this issue.

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?!

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

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?

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 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'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!

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?

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 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?

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

VisionOS 2 beta 5 ，unity text shader errors