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Elapsed scene time used in custom shader uniform
If you create a custom shader you get access to a collection of uniform values, one is the uniforms::time() parameter which is defined as "the number of seconds that have elapsed since RealityKit began rendering the current scene" in this doc: https://developer.apple.com/metal/Metal-RealityKit-APIs.pdf Is there some way to get this value from Swift code? I want to animate a value in my shader based on the time so I need to get the starting time value so I can interpolate the animation offset from that point. If I create a System in the update() function I get a SceneUpdateContext instance and that has a deltaTime property but not an elapsedTime property which I would assume would map to the shader time() value.
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596
Jun ’24
How many warps can be run in parallel on a single shader core?
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?
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451
Aug ’24
RealityView world tracking without camera feed?
Is it possible with iOS 18 to use RealityView with world tracking but without the camera feed as background? With content.camera = .worldTracking the background is always the camera feed, and with content.camera = .virtual the device's position and orientation don't affect the view point. Is there a way to make a mixture of both? My use case is that my app "Encyclopedia GalacticAR" shows astronomical objects and a skybox (a huge sphere), like a VR view of planets, as you can see in the left image. Now that iOS 18 offers RealityView for iOS and iPadOS, I would like to make use of it, but I haven't found a way to display my skybox as environment, instead of the camera feed. I filed the suggestion FB14734105 but hope that somebody knows a workaround...
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Aug ’24
Permission denied: GenerativeFunctionMetrics
A sample of some error messages that are presented in the Xcode log for executon of a program. There is nothing in the messages that will help identify a component as the origin of the message, nor is there a locatable derinition for the various labels and fields of the text. What component or even framework does this set of messages originate? Your search engine is useless because it returns gibberish. It doesn’t even follow the common behavior of SEARCH ENGINES because it takes label strings compounded from common words and searches for the common word instead of using the catenated string that is the internal variable name that is in the text. 2024-06-22 19:45:58.089943-0500 RoomPlanExampleApp[733:30145] [ClientDonation] (+[PPSClientDonation isRegisteredSubsystem:category:]) Permission denied: GenerativeFunctionMetrics / ANEInferenceOperationPrepareForEncode. I am looking for a definition of the error with a way to locate the context in which the error occurs. 2024-06-22 19:45:58.089967-0500 RoomPlanExampleApp[733:30145] [ClientDonation] (+[PPSClientDonation sendEventWithIdentifier:payload:]) Invalid inputs: payload={ aneModelPath = "/System/Library/PrivateFrameworks/RoomScanCore.framework/PrecompiledModels/lcnn_floorplan_model.bundle/H14G.bundle/main/segment_0__ane/net.hwx"; bundleIdentfier = "com.example.apple-samplecode.RoomPlanExampleApp9QSS565686"; } 2024-06-22 19:45:58.094770-0500 RoomPlanExampleApp[733:30145] [ClientDonation] (+[PPSClientDonation sendEventWithIdentifier:payload:]) Invalid inputs: payload={ bundleIdentfier = "com.example.apple-samplecode.RoomPlanExampleApp9QSS565686"; e5FunctionName = main; numSegments = 1; }
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674
Jun ’24
In Metal compute kernels, when do thread variables get spilled into the device memory?
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.
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333
Aug ’24
Different measure units
I am creating a 3D model from multiple images using the photogrammetry session. Now, when the session generates an OBJ file and I measure the distance between two points, the distance is displayed sporadically in different units. Sometimes it's meters, then centimeters, or another unit altogether. How can I tell the photogrammetry session to always create the model in millimeters?
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331
Aug ’24
Vision Pinch 3D Object
Hello Guys, I'm looking for how to look at the 3D object around me, pinch it (from far with eyes and 2 fingers, not touch them) and display a little information on top of it (like little text). If you have the solution you will make me happy (and a bit less stupid too :) ) Cheers Mathis
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Aug ’24
Guideline 4.3(a) Original game misinterpreted as Spam
Hello, our game Nerd Survivors has been identified as spam. The game is based on an original IP and the only games that should share any resemblance with it are from our company. Today we got notified the rejection due to the violation of Guideline 4.3 but there is no reference to the other application or even a contact to the other developer. We do use Unity as our game engine, so some parts of the code might be shared across different games, but i cannot find any other justification of the failure. "Guideline 4.3(a) - Design - Spam We noticed your app shares a similar binary, metadata, and/or concept as apps submitted to the App Store by other developers, with only minor differences. Submitting similar or repackaged apps is a form of spam that creates clutter and makes it difficult for users to discover new apps."
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754
May ’24
IOS issues... Guideline 4.3(a) - Design - Spam
Hey everyone, My game got rejected due to Guideline 4.3. Here's the gameplay video: https://www.youtube.com/watch?v=Vb6uBUsOSDg Does anyone have experience dealing with Guideline 4.3 and can share some insights? I already appealed, explaining that my game has online multiplayer battles, but no response yet. Feeling frustrated after spending six months on this game. Any advice or suggestions would be appreciated. Thanks!
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833
May ’24
ModelEntity with skeletal pose is missing pins
Starting with Xcode Beta 4+, any ModelEntity I load from usdz that contain a skeletal pose has no pins. The pins used to be accessible from a ModelEntity so you could use alignment with other pins. Per the documentation, any ModelEntity with a skeletal pose should have pins that are automatically generated and contained on the entity.pins object itself. https://developer.apple.com/documentation/RealityKit/Entity/pins Is this a bug with the later Xcode betas or is the documentation wrong?
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268
Aug ’24
Rounding errors in last row of entity transform
I'm trying to clone an entity that's somewhere deeper in hierarchy and I want it together with transform that takes into account parents. Initially I made something that would go back through parents, get their transforms and then reduce them to single one. Then I realized that what I'm doing is same as .transformMatrix(relativeTo: rootEntity), but to validate that what I made gives same results I started to print them both and I noticed that for some reason the last row instead of stable (0,0,0,1) is sometimes (0,0,0,0.9999...). I know that there are rounding errors, but I'd assume that 0 and 1 are "magical" in FP world. The only way I can try to explain it, is that .transformMatrix is using some fancy accelerated matrix multiplication and those produce some bigger rounding errors. That would explain slight differences in other fields between my version and function call, but still - the 1 seems weird. Here's function I'm using to compare: func cloneFlattened(entity: Entity, withChildren recursive: Bool) -> Entity { let clone = entity.clone(recursive: recursive) var transforms = [entity.transform.matrix] var parent: Entity? = entity.parent var rootEntity: Entity = entity while parent != nil { rootEntity = parent! transforms.append(parent!.transform.matrix) parent = parent!.parent } if transforms.count > 1 { clone.transform.matrix = transforms.reversed().reduce(simd_diagonal_matrix(simd_float4(repeating: 1)), *) print("QWE CLONE FLATTENED: \(clone.transform.matrix)") print("QWE CLONE RELATIVE : \(entity.transformMatrix(relativeTo: rootEntity))") } else { print("QWE CLONE SINGLE : \(clone.transform.matrix)") } return clone } Sometimes last one is not 1 QWE CLONE FLATTENED: [ [0.00042261832, 0.0009063079, 0.0, 0.0], [-0.0009063079, 0.00042261832, 0.0, 0.0], [0.0, 0.0, 0.0010000002, 0.0], [-0.0013045187, -0.009559666, -0.04027118, 1.0] ] QWE CLONE RELATIVE : [ [0.00042261826, 0.0009063076, -4.681872e-12, 0.0], [-0.0009063076, 0.00042261826, 3.580335e-12, 0.0], [3.4256328e-12, 1.8047965e-13, 0.0009999998, 0.0], [-0.0013045263, -0.009559661, -0.040271178, 0.9999997] ] Sometimes it is QWE CLONE FLATTENED: [ [0.0009980977, -6.1623556e-05, -1.7382005e-06, 0.0], [-6.136851e-05, -0.0009958588, 6.707259e-05, 0.0], [-5.8642554e-06, -6.683835e-05, -0.0009977464, 0.0], [-1.761913e-06, -0.002, 0.0, 1.0] ] QWE CLONE RELATIVE : [ [0.0009980979, -6.1623556e-05, -1.7382023e-06, 0.0], [-6.136855e-05, -0.0009958589, 6.707254e-05, 0.0], [-5.864262e-06, -6.6838256e-05, -0.0009977465, 0.0], [-1.758337e-06, -0.0019999966, -3.7252903e-09, 1.0] ] 0s in last row seem to be stable. It happens both for entities that are few levels deep and those that have only anchor as parent. So far I've never seen any value that would not be "technically a 1", but my hierarchies are not very deep and it makes me wonder if this rounding could get worse. Or is it just me doing something stupid? :)
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290
Aug ’24
xcode16beta run unreal engine has VectorIntrinsics Failed.
LogUnrealMathTest: FAILED: VectorCos: Ref vs Vec ]LogUnrealMathTest: Bad(0.000000): (0.707107 0.500000 0.342019 0.173648) (0.000000 0.000000 0.000000 0.000000) FAILED: VectorCos: Ref vs Vec LogUnrealMathTest: Bad(0.000000): (-0.707107 -0.500000 -0.342021 -0.173648) (-0.000000 -0.000000 -0.000000 -0.000000) LogMac: Error: appError called: Fatal error: [File:/Users/enginej3/Desktop/UE4/Engine/Source/Runtime/Core/Private/Tests/Math/UnrealMathTest.cpp] [Line: 1652] VectorIntrinsics Failed. this error when running after Xcode build success.this error case unreal editor crash.
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461
Aug ’24
Save UIImage with CATransform3D applied
I have a 3х3 Matrix which I need to apply to UIImage and save it in Documents folder. I successfully converted the 3x3 Matrix (represented as [[Double]]) to CATrasform3D and then I have broken my head with trying to figure out how to apply it to UIImage. The only property where I can I apply it is UIView(or UIImageView in case with working with UIImage) transform property. But it has nothing to do with UIImage itself. I can't save the UIImage from transformed the UIImageView with all the transformations. And all the CoreGraphic methods (like concatenate for CGContext) only work with affine transformations which not suits for me. Please give me a hint what direction I should look. Does Apple has native methods or I have to use 3rd party frameworks for this functionality?
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393
Aug ’24
View Matrix in Metal "Game" Sample code
I tried to understand the view matrix. The part from original code as below: private func updateGameState() { /// Update any game state before rendering uniforms[0].projectionMatrix = projectionMatrix let rotationAxis = SIMD3<Float>(1, 1, 0) let modelMatrix = matrix4x4_rotation(radians: rotation, axis: rotationAxis) let viewMatrix = matrix4x4_translation(0.0, 0.0, -8.0) uniforms[0].modelViewMatrix = simd_mul(viewMatrix, modelMatrix) rotation += 0.01 } If the view matrix is initialed in x = -0.5, as:let viewMatrix = matrix4x4_translation(-0.5, 0.0, -8.0) The cube in the MetalView will move left. I think it should move to right hand side because View Matrix is camera position, am I wrong?
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335
Aug ’24
Loading a lighting resource for a RealityKit view on macOS - image not embedded in app bundle
I'm trying to load up a virtual skybox, different from the built-in default, for a simple macOS rendering of RealityKit content. I was following the detail at https://developer.apple.com/documentation/realitykit/environmentresource, and created a folder called "light.skybox" with a single file in it ("prairie.hdr"), and then I'm trying to load that and set it as the environment on the arView when it's created: let ar = ARView(frame: .zero) do { let resource = try EnvironmentResource.load(named: "prairie") ar.environment.lighting.resource = resource } catch { print("Unable to load resource: \(error)") } The loading always fails when I launch the sample app, reporting "Unable to load resource ..." and when I look in the App bundle, the resource that's included there as Contents/Resources/light.realityenv is an entirely different size - appearing to be the default lighting. I've tried making the folder "light.skybox" explicitly target the app bundle for inclusion, but I don't see it get embedded with it toggle that way, or just default. Is there anything I need to do to get Xcode to process and include the lighting I'm providing? (This is inspired from https://stackoverflow.com/questions/77332150/realitykit-how-to-disable-default-lighting-in-nonar-arview, which shows an example for UIKit)
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528
Aug ’24
AirPods pro2麦克风问题
我用的iPhone14ProMax iOS 18.0 beta5 AirPods是最新os 我玩暗区突围时队友说耳机有电流声/滋滋声 噪音很大 有的时候没有有的时候突然就有了 我使用手机麦克风就没有此问题 AirPods不在召唤范围但在保
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306
Aug ’24
Xcode Error in Scene Editor and Entity/Component Architecture
Hello, I'm writing to report an issue (or a documentation error). I am using the Entity/Component Architecture incorporated in the GamePlayKit framework. Additionally, I want to take advantage of the user interface provided by the Scene Editor. This is essential for me if I want to involve more people in the project. The issue occurs when linking the user interface data with the GKScene of the aforementioned framework. The first issue arises when adding a component through the interface as shown in the image Then at that moment: if let scene = GKScene(fileNamed: "GameScene") { // Get the SKScene from the loaded GKScene if let sceneNode = scene.rootNode as! GameScene? { Scene.rootNode is nil, and the scene is not presented. However, I can work around this issue by initializing the scene separately: if let scene = GKScene(fileNamed: "GameScene") { // Get the SKScene loaded separately if let sceneNode = SKScene(fileNamed: "GameScene") as! GameScene? { But from here, two issues arise: The node contains a component, and the scene has been loaded separately When trying to access a specific entity through its SKSpriteNode: self.node?.entity // Is nil It becomes very difficult to access a specific entity. When adding a component, an entity is automatically created. This is demonstrated here: The node contains a component, and the scene has been loaded separately. I only have one way to access this entity, and since there is only one, it's easy: sceneNode.entities[0] But even so, it's not very useful because when I try to access its components, it turns out they don't exist. I just wanted to mention this because it would be very helpful for me if this issue could be resolved. Thank you very much in advance.
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342
Aug ’24