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Scene Kit Rotation - rotating around X and Y axis only, causing Z rotation
I am trying to control the orientation of a box in Scene Kit (iOS) using gestures. I am using the translation in x and y to update the x and y rotation of the SCNNode. After a long search I have realised that x and y rotation will always lead to z rotation, thanks to this excellent post: [https://gamedev.stackexchange.com/questions/136174/im-rotating-an-object-on-two-axes-so-why-does-it-keep-twisting-around-the-thir?newreg=130c66c673f848a7be2873bf675573a9) So I am trying to get the z rotation causes, and then remove this from my object by applying the inverse quaternion however when I rotate the object 90 deg around x, and then 90 deg around Y it behaves VERY weirdly. It is almost behaving as it is in gimbal lock, but I did not think that using quaternion in the way that I am would cause gimbal lock in this way. I am sure it is something I am missing, or perhaps I am not able to remove the z rotation in this way. Thanks! I have added a video of the strange behaviour here [https://github.com/marcusraty/RotationExample/blob/main/Example.MP4) And the code example is here [https://github.com/marcusraty/RotationExample)
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1k
Dec ’23
Crash when running custom train step and layers
My environment: Tensorflow: 2.14, tf-metal: 1.1, M3 Max I am working on an GAN full of residual sum and concatenation. It is trained correctly if using CPU only. However, if I enable GPU, it would cause: oc("mps_slice_1"("(mpsFileLoc): /AppleInternal/Library/BuildRoots/d615290d-668b-11ee-9734-0697ca55970a/Library/Caches/com.apple.xbs/Sources/MetalPerformanceShadersGraph/mpsgraph/MetalPerformanceShadersGraph/Core/Files/MPSGraphUtilities.mm":359:0)): error: 'mps.slice' op failed: length value 32 does not fit within the dimension size (33) with start value (32) /AppleInternal/Library/BuildRoots/d615290d-668b-11ee-9734-0697ca55970a/Library/Caches/com.apple.xbs/Sources/MetalPerformanceShadersGraph/mpsgraph/MetalPerformanceShadersGraph/Core/Files/MPSGraphExecutable.mm:2133: failed assertion `Error: MLIR pass manager failed' Some customization I guess might be related to the error: tf.bitwise.bitwise_xor, tf.concat, tf.pad in custom layers numpy.random in train steps. Another debug hint I found is that the "32" is the number of channel of my models' conv layer, and change as I change the number of channel. Is there anyone know what is wrong? Thank you so much
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623
Dec ’23
GPTK on Apple TV
I did not know that you can also get GPTK when you're working on an AppleTV app. I'm getting back into game programming so I booted up an app I installed on my AppleTV a few months ago and the display showed GPTK so I was able to see performance. Drew
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867
Dec ’23
Create CGColorSpace from CFPropertyList
I am trying to create a custom CGColorSpace in Swift on macOS but am not sure I really understand the concepts. I want to use a custom color space called Spot1 and if I extract the spot color from a PDF I get the following: "ColorSpace<Dictionary>" = { "Cs2<Array>" = ( Separation, Spot1, DeviceCMYK, { "BitsPerSample<Integer>" = 8; "Domain<Array>" = ( 0, 1 ); "Filter<Name>" = FlateDecode; "FunctionType<Integer>" = 0; "Length<Integer>" = 526; "Range<Array>" = ( 0, 1, 0, 1, 0, 1, 0, 1 ); "Size<Array>" = ( 1024 ); } ); }; How can I create this same color space using the CGColorSpace(propertyListPlist: CFPropertyList) API func createSpot1() -> CGColorSpace? { let dict0 : NSDictionary = [ "BitsPerSample": 8, "Domain" : [0,1], "Filter" : "FlateDecode", "FunctionType" : 0, "Length" : 526, "Range" : [0,1,0,1,0,1,0,1], "Size" : [1024]] let dict : NSDictionary = [ "Cs2" : ["Separation","Spot1", "DeviceCMYK", dict0] ] let space = CGColorSpace(propertyListPlist: dict as CFPropertyList) if space == nil { DebugLog("Spot1 color space is nil!") } return space }
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601
Dec ’23
Overloaded operator & device memory
Hi, In a metal shader I have a user-defined struct with a square brackets operator. This is a simplified version of it: struct MyData { float data[12]; float operator[](int i) const { return data[i]; } }; I pass a device buffer of that type in a compute kernel function: device const MyData* myDataBuffer Using the operator with a thread-space object works fine: MyData data_object = myDataBuffer[0]; float x = data_object[0]; // ok ..but trying to use it with the device-space buffer fails: float x = myDataBuffer[0][0]; // compilation error No viable overloaded operator[] for type 'const device MyData' Candidate function not viable: address space mismatch in 'this' argument ('const device MyData'), parameter type must be 'const MyData' For other operators I could define the function outside the struct and pass a reference to a device-memory object but the function for the square brackets operator can only be a member function. Am I missing something that could make the above statement compile?
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433
Dec ’23
How do I change the background color of a visionOS immersive space?
In visionOS, once an immersive space is opened, the background color is solid black. How do I change this? I just need to set a static color without any shading, but I can't find any documentation or examples on how to do this, and the template that comes with Xcode 15.1 beta 3 doesn't change the background color. I've searched around for information, but all I can find points back to MTKView.clearColor, which I can't use when drawing into an immersive space, since immersive spaces on visionOS use Compositor Services and not MTKView or CAMetalLayer for drawing 3D content.
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1.1k
Dec ’23
iOS 16 & 17 touch input stutter on Pro Motion devices. Workaround?
The touch input stutter issue that exists since iOS 16 on devices with Pro Motion Displays has not been fixed yet. I filed a bug report in July but there isn't any progress since months. I see the problem in all games I tried. My game is fast paced so the stutters are quite obvious and I receive a lot of complaining emails. My game did run smoothly on Pro Motion devices with iOS 15. Is there a known workaround? I am seeing other developers having the same issue but I can't find any solutions. Other threads about this issue: IPhone 14 Pro stuttering in most games when using touch controls FPS drops when tapping the screen on iPhone 13 Pro Max
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829
Dec ’23
MTLVertexDescriptor's offset -- everybody's doing it wrong
In pretty much every Metal tutorial out there, people use MTLVertexDescriptor like this: they create a struct like struct Vertex { var position: float3 var color: float3 } then a vertex array and buffer: let vertices: [Vertex] = ... guard let vertexBuffer = device.makeBuffer(bytes: vertices, length: MemoryLayout<Vertex>.stride * vertices.count, options: []) else { ... } This is all good, we have a buffer with interleaved position and color data. The problem is, when creating a vertex descriptor, they use MemoryLayout<float3>.stride as the offset for the second attribute: let vertexDescriptor = MTLVertexDescriptor() vertexDescriptor.attributes[0].format = .float3 vertexDescriptor.attributes[0].offset = 0 vertexDescriptor.attributes[0].bufferIndex = 0 vertexDescriptor.attributes[1].format = .float3 vertexDescriptor.attributes[1].offset = MemoryLayout<float3>.stride // <-- here! vertexDescriptor.attributes[1].bufferIndex = 0 vertexDescriptor.layouts[0].stride = MemoryLayout<Vertex>.stride This does not look correct to me. The code happens to work only because the stride of SIMD3<Float> (a.k.a. float3) matches the alignment of the fields in this particular struct. But if we have something like this: struct Vertex { var attr0: Float var attr1: Float var attr2: SIMD3<Float> } then the naive approach of using stride won't work. Because of padding, attr2 does not start right after the two floats, at offset 2 * MemoryLayout<Float>.stride but at offset = 16. So it seems to me that the only correct and robust way to set the vertex descriptor's offset is to use offset(of:), like this: vertexDescriptor.attributes[2].offset = MemoryLayout<Vertex>.offset(of: \.attr2)! Yet, I'm not able to find a single code example that does this. Am I missing something, or is everybody else just being careless with their offsets?
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351
Dec ’23
Seeking Clarification on UsdPrimvarReader Node Functionality
Hello fellow developers, I am currently exploring the functionality of the UsdPrimvarReader node in Shader Graph Editor and would appreciate some clarification on its operational principles. Despite my efforts to understand its functionality, I find myself in need of some guidance. Specifically, I would appreciate insights into the proper functioning of the UsdPrimvarReader node, including how it should ideally operate, the essential data that should be specified in the Varname field, and the Primvars that can be extracted from a USD file. Additionally, I am curious about the correct code representation of a Primvar in USD file to ensure it can be invoked successfully. If anyone could share their expertise or point me in the right direction to relevant documentation, I would be immensely grateful. Thank you in advance for your time and consideration. I look forward to any insights or recommendations you may have.
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749
Dec ’23
Strange error when using memory barrier in MTLRenderCommandEncoder with imageblocks
I'm attempting to put two mesh draws into a MTLRenderCommandEncoder with a memory barrier between them. I'm also using image blocks in the fragment functions in the two pipelines. Something like this: [encoder setRenderPipelineState:pipeline1]; [encoder drawMeshThreadgroups:threadgroupsPerGrid threadsPerObjectThreadgroup:threadsPerObjectThreadgroup threadsPerMeshThreadgroup:threadsPerMeshThreadgroup]; [encoder memoryBarrierWithScope:MTLBarrierScopeBuffers afterStages:MTLRenderStageMesh beforeStages:MTLRenderStageObject]; [encoder setRenderPipelineState:pipeline2]; [encoder drawMeshThreadgroups:threadgroupsPerGrid threadsPerObjectThreadgroup:threadsPerObjectThreadgroup threadsPerMeshThreadgroup:threadsPerMeshThreadgroup]; I get a strange error: Execution of the command buffer was aborted due to an error during execution. Too many unique viewports, scissor rectangles or depth-bias values to support memoryless render pass attachments. (0000000c:kIOGPUCommandBufferCallbackErrorExceededHardwareLimit) I'm not using multiple viewports or scissor rectangles and I'm not using depth bias. I don't have memoryless attachments, though as mentioned, I am using imageblocks. Without the memory barrier I don't get the error. Using memoryBarrierWithResources rather than memoryBarrierWithScope This is on an M2 Max running 14.3 Beta (23D5033f) I can't tell if I encountered a real limitation or a Metal driver bug.
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376
Dec ’23
Multiple root level objects Error [USDZ/Reality Composer Pro]
Hey everyone, I'm running into this issue of my USDZ model not showing up in Reality Composer Pro, exported from Blender as a USD and converted in Reality Converter. See Attached image: It's strange, because the USDz model appears fine in Previews. But once it is brought inside RCP, I receive this pop up, and does not appear. Not sure how to resolve this multiple root level issue. If anyone can point me in the right direction or any feedback, all is much appreciated! Thank you!
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1.1k
Dec ’23
Apple Core Package for Unity
I have installed the aple game kit and when it is time to build the packages i go to unity pakage manager and find the .tgz file and open it but the apple core pakage does not appear on the list inside package manager. Using unity 2022.2.2 [08:53:18] [Package Manager Window] Error adding package: file:./Assets/External Packages/unityplugins-main/Build/fbx20133_converter_mac.pkg.tgz. Unable to add package file: /Assets/External Packages/unitvolugins-main/Build/fbx20133 converter mac.nka.tazl: [08:56:07] [Package Manager Window] Error adding package: file:./Assets/External Packages/unityplugins-main/Build/fbx20133_converter_mac.pkq.tqz. Unable to add package tile:.. Assets/External Packages unitvplugins-mainBulld/TbX20133_converter mac.pka.taz: [08:59:311 [Package Manager Window] Error adding package: file../ Assets/External Packages/unityplugins-main/Build/fbx20133_converter_mac.pkg.tgz. unable to add package TIle….. AssETS/External Packages unityplugins-main/Bulld/TOX20133_converter_mac.pkq.tqz: [09:03:111 [Package Manager Window] Error adding package: file../Assets/External Packages/unityplugins-main/Build/fbx20133_converter_mac.pkg.tgz. unable to add package Tile:.. AssEts/Extemalackagesunitypiugins-main/Bulla/TOXU133_convener_mac.pko.toz]: ¿ Perso [Package Manager Window] Error adding package: file:./ Assets/External Packages/unityplugins-main/Build/fbx20133_converter_mac.pkg.tgz. Unable to add package [file:../Assets/External Packages/unityplugins-main/Build/fbx20133_converter_mac.pkg.tgz]: The file L/var/folders/39/drmm3vg15tsggs7nt7z360lh0000gn/T/.tmp-9365-Q2GPWMjILnkO/package.json] cannot be found
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745
Dec ’23
Is CAMetalDisplayLink expected to support Metal Performance HUD?
I've been attempting to use the new CAMetalDisplayLink to simplify the code needed to sync my rendering with the display across Apple platforms. One thing I noticed since moving to using CAMetalDisplayLink is that the Metal Performance HUD which I had previously been using to analyze the total memory used by my app (among other things) is suddenly no longer appearing when using CAMetalDisplayLink. This issue can be reproduced with the Frame Pacing sample from WWDC23 Anyone from Apple know if this is expected behavior or have an idea on how to get this to work properly? I've filed FB13495684 for official review.
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755
Dec ’23
When is a `simdgroup_barrier()` required?
Metal offers both threadgroup_barrier() and simdgroup_barrier(). I understand the need for threadroup barriers — it would not be possible to rely on well cooperation between threads in a threadgroup without them, as different threads can execute on different SIMD partitions at different times. But I don't really get the simdgroup_barrier() — it was my impression that all threads in a simdgroup execute in lockstep and this if one thread in a simdgroup makes progress, all other active threads in the simdgroup are also guaranteed to make progress. If this were not the case we'd need to insert simdgroup barrier pretty much any time we read or write any storage or perform SIMD-scoped operations. It doesn't seem like Apple uses simdgroup_barrier() in any of their sample code. In fact, it seems like it's a no-op on current Apple Silicon hardware. Is there a situation when I need to use simdgroup barriers or is this a superfluous operation? P.S. It seems that Apple engineers are as confused by this as I am, see https://github.com/ml-explore/mlx/blame/1f6ab6a556045961c639735efceebbee7cce814d/mlx/backend/metal/kernels/scan.metal#L355
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840
Dec ’23
App renders as a black on screen
Hello, I am creating an application that is cross-platform with Flutter, the problem is that when I launch my application on my Macbook there is only a black page displayed. This is a recurring problem with all Flutter applications on this Mac. When I debug my application, this is what appears in the console. Error submitting command buffer. 2023-12-27 15:58:12.468 tranzic[2333:21044] Error Domain=MTLCommandBufferErrorDomain Code=4 "Ignored (for causing prior/excessive GPU errors) (00000004:kIOAccelCommandBufferCallbackErrorSubmissionsIgnored)" UserInfo={NSLocalizedDescription=Ignored (for causing prior/excessive GPU errors) (00000004:kIOAccelCommandBufferCallbackErrorSubmissionsIgnored), MTLCommandBufferEncoderInfoErrorKey=( "<errorState: MTLCommandEncoderErrorStatePending, label: (null), debugSignposts: (null)>", "<errorState: MTLCommandEncoderErrorStatePending, label: (null), debugSignposts: (null)>", "<errorState: MTLCommandEncoderErrorStatePending, label: (null), debugSignposts: (null)>" )} Error submitting command buffer. 2023-12-27 15:58:18.455 tranzic[2333:21044] Error Domain=MTLCommandBufferErrorDomain Code=4 "Ignored (for causing prior/excessive GPU errors) (00000004:kIOAccelCommandBufferCallbackErrorSubmissionsIgnored)" UserInfo={NSLocalizedDescription=Ignored (for causing prior/excessive GPU errors) (00000004:kIOAccelCommandBufferCallbackErrorSubmissionsIgnored), MTLCommandBufferEncoderInfoErrorKey=( "<errorState: MTLCommandEncoderErrorStatePending, label: (null), debugSignposts: (null)>", "<errorState: MTLCommandEncoderErrorStatePending, label: (null), debugSignposts: (null)>", "<errorState: MTLCommandEncoderErrorStatePending, label: (null), debugSignposts: (null)>" )} I have a Macbook Pro mid-2012 running macOS Monterey and here's an issue I opened on the flutter repo for more details. https://github.com/flutter/flutter/issues/137859
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633
Dec ’23