Hi, I have been getting the following crash in my app which has a Custom Metal Render Engine CoreFoundation                   -[__NSSetM clumpingFactor] + 264 libobjc.A.dylib                  __objc_empty_cache + 888 CoreAutoLayout                   DA979160-E330-3C35-BF6F-D3248DCC3246 + 67536 CoreAutoLayout                   DA979160-E330-3C35-BF6F-D3248DCC3246 + 68272 UIKitCore                        __OBJC_$_INSTANCE_METHODS__UIDatePickerCalendarTimeLabel + 600 UIKitCore                        __OBJC_$_INSTANCE_METHODS__UINavigationBarStarkVisualStyle + 100 UIKitCore                        ___79+[UISwitchModernVisualElement _modernThumbImageWithColor:mask:traitCollection:]_block_invoke_2 + 204 UIKitCore                        -[UISwitchModernVisualElement _switchTrackPositionAnimationWithFromValue:toValue:on:] + 388 UIKitCore                        -[UISwitchModernVisualElement _effectiveGradientImage] + 128 UIKitCore                        __OBJC_$_INSTANCE_METHODS__UISearchBarVisualProviderLegacy + 1924 QuartzCore                       CA::Layer::add_animation(CAAnimation*, __CFString const*) + 72 QuartzCore                       CA::Layer::remove_sublayer(CA::Transaction*, CALayer*) + 272 QuartzCore                       CA::OGL::Context::draw_elements(CA::OGL::PrimitiveMode, unsigned int, unsigned short const*, CA::OGL::Vertex const*, unsigned int, unsigned int, CA::OGL::ClipPlane const*) + 60 QuartzCore                       CAML::cgcolor_end(CAML::Context*, CAML::State*, char*, unsigned long) + 1252 QuartzCore                       native_window_swap(_EAGLNativeWindowObject*, unsigned int, double) + 712 QuartzCore                       -[CAStateControllerAnimation initWithLayer:key:] + 52 CoreFoundation                   ___CFSocketSetSocketReadBufferAttrs + 444 CoreFoundation                   __CFNonObjCEqual + 8 CoreFoundation                   __CFRelease + 952 Foundation                       4E7D1FF6-6B64-3833-9E60-CC662AFE2647 + 36236 danmu                            -[DMEngineBase runMetalThread] (in DMEngineBase.mm:148) Foundation                       4E7D1FF6-6B64-3833-9E60-CC662AFE2647 + 1549068 libsystem_pthread.dylib          _pthread_rwlock_unlock$VARIANT$armv81 + 160 libsystem_pthread.dylib          __pthread_create + 1196 this crash seems caused by the Metal Thread Rendering which triggered a CoreAnimation drawing and finally crashed at CoreAutoLayout internal method : Crashed View : appEnterForeground Exception Name : NSInternalInconsistencyException Exception Reason : Modifications to the layout engine must not be performed from a background thread after it has been accessed from the main thread. In the latest Version I have been trying solved this crash by add some protected like this : - (void)runMetalThread {   NSRunLoop *runLoop = [NSRunLoop currentRunLoop];   [_displayLink addToRunLoop:runLoop forMode:DMMetalRunLoopModelFrame];   BOOL continueRunLoop = YES;   while (continueRunLoop)   {     @autoreleasepool     {       [runLoop runMode:DMMetalRunLoopModelFrame beforeDate:[NSDate distantFuture]];     }     continueRunLoop = _continueRunLoop;   } } - (void)onBulletDraw:(CADisplayLink*)displayLink {   self.renderer.stoped = !_isActive || _stoped;   self.renderer.paused = _isPaused;   [self.renderer onDanmuDraw:displayLink]; } #pragma mark - Notification - (void)willResignActive {   self.isActive = NO;   MTLog(@"metal# engine %@ resign active", self); } - (void)didBecomeActive {   //Protected by delay active the metal engine after app state didBecomeActive   dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.7 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{     if (UIApplication.sharedApplication.applicationState == UIApplicationStateActive) {       self.isActive = YES;       MTLog(@"metal# engine %@ become active", self);     }else{       MTLog(@"metal# engine still inactive after 0.7s");     }   }); } this protected has make sure to STOPed the Metal Render after the app resign active, and seems has some effect which reduced 84% crashes on my released app . but it did not completely solve this problem still has 16% crashes in some unknown scene . I have been checked all my Metal Rendering thread code , I can be guaranteed that no method will trigger CoreAnimation drawing in this metal thread. So is there has an Perfective Solution of this bug ?

Hello all, I need my texture to be not premultiplied alpha, because is use the alpha for some additional calculations in the fragment shader. At the moment I load my texture like this let textureLoader = MTKTextureLoader(device: sceneView.device!) myTexture = try textureLoader.newTexture(URL: URL(fileURLWithPath: path!), options: [MTKTextureLoader.Option.SRGB: false]) because I need the raw RGBA values. But of course it gets premultiplied. How can I turn off this behavior?

I notice that when I open the Photos app on my iPhone 12 Pro, viewing Photos or Videos shot in HDR makes them brighter than the overall display brightness level. On macOS, there are APIs like EDRMetadata on CAMetalLayer and maximumExtendedDynamicRangeColorComponentValue on NSScreen. I did see CAMetalLayer.wantsExtendedDynamicRangeContent, but I'm not sure if this does what I'm looking for. The "Using Color Spaces to Display HDR Content" - https://developer.apple.com/documentation/metal/drawable_objects/displaying_hdr_content_in_a_metal_layer/using_color_spaces_to_display_hdr_content?language=objc documentation page describes setting the .colorspace on the CAMetalLayer for BT2020_PQ content, but it's not clear if this is referring to macOS or iOS. Is that the right way to get colors to be "brighter" than 1.0 on "XDR" mobile displays?

I have CVPixelBuffer's in kCVPixelFormatType_420YpCbCr10BiPlanarVideoRange, which is 10 bit HDR. I need to convert these to RGB and display in MTKView. I need to know the correct pixel format to use, the BT2020 conversion matrix, and displaying the 10 bit RGB pixel buffer in MTKView.

When I use metal to render, the application switch to the background resulting in metal rendering failure in iOS 15 sys. How can I do? Error: Execution of the command buffer was aborted due to an error during execution.Insufficient Permission (to submit GPU work from background) (00000006:kIOGPUCommandBufferCallbackErrorBackgroundExecutionNotPermitted)

I have tried everything but it looks to be impossible to get MTKView to display full range of colors of HDR CIImage made from CVPixelBuffer (in 10bit YUV format). Only builtin layers such as AVCaptureVideoPreviewLayer, AVPlayerLayer, AVSampleBufferDisplayLayer are able to fully display HDR images on iOS. Is MTKView incapable of displaying full BT2020_HLG color range? Why does MTKView clip colors no matter even if I set pixel Color format to bgra10_xr or bgra10_xr_srgb?  convenience init(frame: CGRect, contentScale:CGFloat) {         self.init(frame: frame)         contentScaleFactor = contentScale     }     convenience init(frame: CGRect) {         let device = MetalCamera.metalDevice         self.init(frame: frame, device: device)         colorPixelFormat = .bgra10_xr         self.preferredFramesPerSecond = 30     }     override init(frame frameRect: CGRect, device: MTLDevice?) {         guard let device = device else {             fatalError("Can't use Metal")         }         guard let cmdQueue = device.makeCommandQueue(maxCommandBufferCount: 5) else {             fatalError("Can't make Command Queue")         }         commandQueue = cmdQueue         context = CIContext(mtlDevice: device, options: [CIContextOption.cacheIntermediates: false])         super.init(frame: frameRect, device: device)         self.framebufferOnly = false         self.clearColor = MTLClearColor(red: 0, green: 0, blue: 0, alpha: 0)     } And then rendering code:  override func draw(_ rect: CGRect) {         guard let image = self.image else {             return         }         let dRect = self.bounds         let drawImage: CIImage         let targetSize = dRect.size         let imageSize = image.extent.size         let scalingFactor = min(targetSize.width/imageSize.width, targetSize.height/imageSize.height)         let scalingTransform = CGAffineTransform(scaleX: scalingFactor, y: scalingFactor)         let translation:CGPoint = CGPoint(x: (targetSize.width - imageSize.width * scalingFactor)/2 , y: (targetSize.height - imageSize.height * scalingFactor)/2)         let translationTransform = CGAffineTransform(translationX: translation.x, y: translation.y)         let scalingTranslationTransform = scalingTransform.concatenating(translationTransform)        drawImage = image.transformed(by: scalingTranslationTransform)         let commandBuffer = commandQueue.makeCommandBufferWithUnretainedReferences()         guard let texture = self.currentDrawable?.texture else {             return         }         var colorSpace:CGColorSpace                 if #available(iOS 14.0, *) {             colorSpace = CGColorSpace(name: CGColorSpace.itur_2100_HLG)!         } else {             // Fallback on earlier versions             colorSpace = drawImage.colorSpace ?? CGColorSpaceCreateDeviceRGB()         }         NSLog("Image \(colorSpace.name), \(image.colorSpace?.name)")         context.render(drawImage, to: texture, commandBuffer: commandBuffer, bounds: dRect, colorSpace: colorSpace)         commandBuffer?.present(self.currentDrawable!, afterMinimumDuration: 1.0/Double(self.preferredFramesPerSecond))         commandBuffer?.commit()     }

I was following raywenderlich's Metal tutorial, but got stuck rendering a texture on a plane, it seems to be showing only one color of the image, not the entire image. I'm running on an iPad iOS 12.3. The weirdest thing is that I can render a multicolored rectangle when the texture is nil, but can't render the texture. Here's a repo for the project: https://github.com/TheJoseph-Dev/MyMetalProgram May anyone help me?

While developing my Metal application I noticed that making a draw call is a lot slower than using a tile shader. In particular, when operating on a 4k resolution texture it takes about 3ms to complete a draw call while the tile shader takes about 150ns. I was wondering, is a tile shader the preferred approach for drawing with Metal now? Or is there any particular reason why a typical draw call should be used.

I have a 3D scene with a perspective camera and I'd like some of the elements to be projected using an orthographic projection instead. My use case is that I have some 3D elements with attached text nodes. I'd like the text on these nodes to always be the same size no matter how far away the camera is. Is there a way I can use SceneKit to mix and match? Or is there another technique I can use?

I am trying to push content to an MTKView in SwiftUI, wrapped in a UIViewRepresentable by manually calling draw(in: MTKView) on the MTKViewDelegate. My question is how to obtain and release the correct drawable from the 3 available. As I only want to push draw calls from an external source, the view settings are: mtkView.isPaused = true // only push data mtkView.enableSetNeedsDisplay = false // only push data from our single source mtkView.framebufferOnly = true // we don't render to anything but the screen The MTKViewDelegate draw call is as follows: func draw(in view: MTKView) { autoreleasepool() { let passDescriptor = view.currentRenderPassDescriptor! // make command buffer, encoder from descriptor // encode data let drawable = view.currentDrawable! commandBuffer.present(drawable) commandBuffer.commit() } } This works fine for the first trigger of draw and on the second draw call raises [CAMetalLayerDrawable texture] should not be called after already presenting this drawable. Get a nextDrawable instead. and Each CAMetalLayerDrawable can only be presented once! Setting mtkView.isPaused = false renders fine, so I suppose whatever internal loop is handling calling nextDrawable(). How should I go about ensuring that I am getting the next drawable and releasing the current one when I assume control of drawing? Best regards,

Hello, could you please advise how to use UIScrollView with MTKView. So I have 3 MTKViews and want to scroll them up and down. A have error with drawable

I am just starting to learn AR. Thanks for the help. I am trying to bind large objects to a certain location in an open area. I tried to bind using an image, an object in a reality composer. After snapping, when moving, objects do not remain in the same place. ARGeoTrackingConfiguration is not available in my region. If you scan the world around you and then define it, then with a rainy day or the slightest change in the area (for example, mowing the lawn), the terrain will not be determined. What do you advise?

Given six KTX, ASTC compressed textures -- all equal in size and attributes -- a.ktx, b.ktx, c.ktx, d.ktx, e.ktx, & f.ktx, I can embed them in the bundle and then create a working cube via- let cube = MDLTexture(cubeWithImagesNamed: [ "a.ktx", "b.ktx", "c.ktx", "d.ktx", "e.ktx", "f.ktx"]) This can be assigned to background.contents and works great. If, on the other hand, I have loaded those six textures from some other source into six separate MTLTextures, I cannot provide them as an array to background.contents (it fails with "image at index 0 is NULL). I have attempted to create a cube MTLTexture with the appropriate MTLTextureDescriptor.textureCubeDescriptor (using the pixel format and other attributes from the source textures), then copying the data via MTLBlitCommandEncoder, however the end result, while error free, is a cube that is wholly purple. I suspect this may be that the source textures are ASTC compressed, but am a bit at a loss as the documentation is rather sparse. Everything else seems to be incredibly easy relative to this very simple need of creating a cube from textures that aren't named bundle items. Any guidance or hints would be greatly appreciated.