After watching WWDC 2025 session "Combine Metal 4 machine learning and graphics", I have decided to give it a shot to integrate the latest MTL4MachineLearningCommandEncoder to my existing render pipeline. After a lot of trial and errors, I managed to set up the pipeline and have the app compiled.
However, I am now stuck on creating a MTLLibrary with .mtlpackage.
Here is the code I have to create a MTLLibrary according the WWDC session https://developer.apple.com/videos/play/wwdc2025/262/?time=550:
let coreMLFilePath = bundle.path(forResource: "my_model", ofType: "mtlpackage")!
let coreMLURL = URL(string: coreMLFilePath)!
do {
metalDevice.makeLibrary(URL: coreMLURL)
} catch {
print("error: \(error)")
}
With the above code, I am getting error:
Error Domain=MTLLibraryErrorDomain Code=1 "Invalid metal package" UserInfo={NSLocalizedDescription=Invalid metal package}
What is the correct way to create a MTLLibrary with .mtlpackage? Do I see this error because the .mtlpackage I am using is incorrect? How should I go with debugging this?
I'd really appreciate if I could get some help on this as I have been stuck with it for some time now. Thanks in advance!
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I recently needed to develop an application to obtain the window list, which requires Screen Recording permissions. Apple's official documentation mentions using the two functions CGPreflightScreenCaptureAccess and CGRequestScreenCaptureAccess to request permissions. These functions are stated to be available since version 10.15. However, when I used these two functions on a device running macOS 10.15.7, I encountered the errors shown in the attached screenshot. I used the nm tool to inspect the symbols in the CoreGraphics.framework and found that these two functions were not present. Could you help me understand why this is happening?
Topic:
Graphics & Games
SubTopic:
General
I've tried out a ParticleEmitter in Reality Composer Pro to produce a burst of particles that don't move (i.e. speed close to zero).
When viewing from different angles, it clearly looks like the particles are rendered exactly in the wrong order, that is, front first and back last. In other words, back particles obscure front particles.
I would prefer it the correct way around.
I've only tried this interactively in Reality Composer Pro, not programmatically, but I assume I would get the same result.
My Reality Composer Pro "File" (zipped):
https://gert-rieger-edv.de/Posts/Post-1/RealityParticles.zip
Screenshot:
Click on the ParticleEmitter object, then on its Play button, then select the Particles tab and click on "Burst" a few times to get a few random particles.
Mac Studio 2025
Apple M4 Max
macOS 15.7.2 (24G325)
Reality Composer Pro
Version 2.0 (494.60.2)
Hey I'm using the CIDepthBlurEffect Core Image Filter in my app. It seems to work ok but I get these errors in the console when calling the class.
CoreImage Metal library does not contain function for name: sparserendering_xhlrb_scan
CoreImage Metal library does not contain function for name: sparserendering_xhlrb_diffuse
CoreImage Metal library does not contain function for name: sparserendering_xhlrb_copy_back
CoreImage Metal library does not contain function for name: plain_or_sRGB_copy
Am I missing some sort of import to gain these Metal functions? I am using my own custom shaders but I assume you'd be able to use them along side the built in ones.
Was wondering if anyone from Apple could provide some clarification, The gaming studio "Epic Games" Is wondering if they could distribute the award winning game "Fortnite" back on MacOS without any retaliations.
I know Fortnite being back on MacOS would benefit thousands of MacOS Devs. Hoping to get a clarification so Epic could start on bringing Fortnite back.
I am trying to implement a ChacterControllerComponent using the following URL.
https://developer.apple.com/documentation/realitykit/charactercontrollercomponent
I have written sample code, but PhysicsSimulationEvents.WillSimulate is not executed and nothing happens.
import SwiftUI
import RealityKit
import RealityKitContent
struct ImmersiveView: View {
let gravity: SIMD3<Float> = [0, -50, 0]
let jumpSpeed: Float = 10
enum PlayerInput {
case none, jump
}
@State private var testCharacter: Entity = Entity()
@State private var myPlayerInput = PlayerInput.none
var body: some View {
RealityView { content in
// Add the initial RealityKit content
if let immersiveContentEntity = try? await Entity(named: "Immersive", in: realityKitContentBundle) {
content.add(immersiveContentEntity)
testCharacter = immersiveContentEntity.findEntity(named: "Capsule")!
testCharacter.components.set(CharacterControllerComponent())
let _ = content.subscribe(to: PhysicsSimulationEvents.WillSimulate.self, on: testCharacter) {
event in
print("subscribe run")
let deltaTime: Float = Float(event.deltaTime)
var velocity: SIMD3<Float> = .zero
var isOnGround: Bool = false
// RealityKit automatically adds `CharacterControllerStateComponent` after moving the character for the first time.
if let ccState = testCharacter.components[CharacterControllerStateComponent.self] {
velocity = ccState.velocity
isOnGround = ccState.isOnGround
}
if !isOnGround {
// Gravity is a force, so you need to accumulate it for each frame.
velocity += gravity * deltaTime
} else if myPlayerInput == .jump {
// Set the character's velocity directly to launch it in the air when the player jumps.
velocity.y = jumpSpeed
}
testCharacter.moveCharacter(by: velocity * deltaTime, deltaTime: deltaTime, relativeTo: nil) {
event in
print("playerEntity collided with \(event.hitEntity.name)")
}
}
}
}
}
}
The scene is loaded from RCP. It is simple, just a capsule on a pedestal.
Do I need a separate code to run testCharacter from this state?
After updating iPad/iPhone devices from iOS 18 to iOS 26, PhotogrammetrySession intermittently crashes during photogrammetry processing. The same workflow was stable on iOS 18 with no code changes to the app.
Environment:
OS versions: Works on OS 18, crashes on OS 26
Device: iPad/iPhone (reproducible across devices)
Source images: ~170-200 JPG files at 2160 x 3840 resolution
Reproduction:
The crash occurs consistently on the second or third sequential run of the photogrammetry session with the same image set. First run typically succeeds.
Crash details:
Xcode shows an uncaught exception during image processing:
terminating due to uncaught exception of type std::bad_alloc: std::bad_alloc
VTPixelTransferSession 420f sid 269 (2160.00 x 3840.00) [0.00 0.00 2160 3840]
rowbytes( 2160, 2160 ) Color( (null), 0x0, (null), (null), ITU_R_601_4 )
=> 24 sid 19 (2160.00 x 3840.00) [0.00 0.00 2160 3840] rowbytes( 6528 )
Color( 0x0, (null), (null), (null) )
This appears to be a memory allocation failure in VTPixelTransferSession during color space conversion. Has anyone else experienced similar crashes with CorePhotogrammetry on iOS 26, or found workarounds?
Topic:
Graphics & Games
SubTopic:
RealityKit
Context
I’m deploying large language models on iPhone using llama.cpp. A new iPhone Air (12 GB RAM) reports a Metal MTLDevice.recommendedMaxWorkingSetSize of 8,192 MB, and my attempt to load Llama-2-13B Q4_K (~7.32 GB weights) fails during model initialization.
Environment
Device: iPhone Air (12 GB RAM)
iOS: 26
Xcode: 26.0.1
Build: Metal backend enabled llama.cpp
App runs on device (not Simulator)
What I’m seeing
MTLCreateSystemDefaultDevice().recommendedMaxWorkingSetSize == 8192 MiB
Loading Llama-2-13B Q4_K (7.32 GB) fails to complete. Logs indicate memory pressure / allocation issues consistent with the 8 GB working-set guidance.
Smaller models (e.g., 7B/8B with similar quantization) load and run (8B Q4_K provide around 9 tokens/second decoding speed).
Questions
Is 8,192 MB an expected recommendedMaxWorkingSetSize on a 12 GB iPhone?
What values should I expect on other 2025 devices including iPhone 17 (8 GB RAM) and iPhone 17 Pro (12 GB RAM)
Is it strictly enforced by Metal allocations (heaps/buffers), or advisory for best performance/eviction behavior?
Can a process practically exceed this for long-lived buffers without immediate Jetsam risk?
Any guidance for LLM scenarios near the limit?
Problem Summary
After upgrading to iOS 26.1 and 26.2, I'm experiencing a particle positioning bug in RealityKit where ParticleEmitterComponent particles render at an incorrect offset relative to their parent entity. This behavior does not occur on iOS 18.6.2 or earlier versions, suggesting a regression introduced in the newer OS builds.
Environment Details
Operating System: iOS 26.1 & iOS 26.2
Framework: RealityKit
Xcode Version: 16.2 (16C5032a)
Expected vs. Actual Behavior
Expected: Particles should render at the position of the entity to which the ParticleEmitterComponent is attached, matching the behavior on iOS 18.6.2 and earlier.
Actual: Particles appear away from their parent entity, creating a visual misalignment that breaks the intended AR experience.
Steps to Reproduce
Create or open an AR application with RealityKit that uses particle components
Attach a ParticleEmitterComponent to an entity via a custom system
Run the application on iOS 26.1 or iOS 26.2
Observe that particles render at an offset position away from the entity
Minimal Code Example
Here's the setup from my test case:
Custom Component & System:
struct SparkleComponent4: Component {}
class SparkleSystem4: System {
static let query = EntityQuery(where: .has(SparkleComponent4.self))
required init(scene: Scene) {}
func update(context: SceneUpdateContext) {
for entity in context.scene.performQuery(Self.query) {
// Only add once
if entity.components.has(ParticleEmitterComponent.self) { continue }
var newEmitter = ParticleEmitterComponent()
newEmitter.mainEmitter.color = .constant(.single(.red))
entity.components.set(newEmitter)
}
}
}
AR Setup:
let material = SimpleMaterial(color: .gray, roughness: 0.15, isMetallic: true)
let model = Entity()
model.components.set(ModelComponent(mesh: boxMesh, materials: [material]))
model.components.set(SparkleComponent4())
model.position = [0, 0.05, 0]
model.name = "MyCube"
let anchor = AnchorEntity(.plane(.horizontal, classification: .any, minimumBounds: [0.2, 0.2]))
anchor.addChild(model)
arView.scene.addAnchor(anchor)
Questions for the Community
Has anyone else encountered this particle positioning issue after updating to iOS 26.1/26.2?
Are there known workarounds or configuration changes to ParticleEmitterComponent that restore correct positioning?
Is this a confirmed bug, or could there be a change in coordinate system handling or transform inheritance that I'm missing?
Additional Information
I've already submitted this issue via Feedback Assistant(FB21346746)
iPhone(14 Pro Max)で端末の画面にリフレッシュレートを表示させたいのですが、どなたか方法をご存知ないでしょうか?
Topic:
Graphics & Games
SubTopic:
General
Create the QRCode
CIFilter<CIBlendWithMask> *f = CIFilter.QRCodeGenerator;
f.message = [@"Message" dataUsingEncoding:NSASCIIStringEncoding];
f.correctionLevel = @"Q"; // increase level
CIImage *qrcode = f.outputImage;
Overlay the icon
CIImage *icon = [CIImage imageWithURL:url];
CGAffineTransform *t = CGAffineTransformMakeTranslation(
(qrcode.extent.width-icon.extent.width)/2.0,
(qrcode.extent.height-icon.extent.height)/2.0);
icon = [icon imageByApplyingTransform:t];
qrcode = [icon imageByCompositingOver:qrcode];
Round off the corners
static dispatch_once_t onceToken;
static CIWarpKernel *k;
dispatch_once(&onceToken, ^ {
k = [CIWarpKernel kernelWithFunctionName:name
fromMetalLibraryData:metalLibData()
error:nil];
});
CGRect iExtent = image.extent;
qrcode = [k applyWithExtent:qrcode.extent
roiCallback:^CGRect(int i, CGRect r) {
return CGRectInset(r, -radius, -radius); }
inputImage:qrcode
arguments:@[[CIVector vectorWithCGRect:qrcode.extent], @(radius)]];
…and this code for the kernel should go in a separate .ci.metal source file:
float2 bend_corners (float4 extent, float s, destination dest)
{
float2 p, dc = dest.coord();
float ratio = 1.0;
// Round lower left corner
p = float2(extent.x+s,extent.y+s);
if (dc.x < p.x && dc.y < p.y) {
float2 d = abs(dc - p);
ratio = min(d.x,d.y)/max(d.x,d.y);
ratio = sqrt(1.0 + ratio*ratio);
return (dc - p)*ratio + p;
}
// Round lower right corner
p = float2(extent.x+extent.z-s, extent.y+s);
if (dc.x > p.x && dc.y < p.y) {
float2 d = abs(dc - p);
ratio = min(d.x,d.y)/max(d.x,d.y);
ratio = sqrt(1.0 + ratio*ratio);
return (dc - p)*ratio + p;
}
// Round upper left corner
p = float2(extent.x+s,extent.y+extent.w-s);
if (dc.x < p.x && dc.y > p.y) {
float2 d = abs(dc - p);
ratio = min(d.x,d.y)/max(d.x,d.y);
ratio = sqrt(1.0 + ratio*ratio);
return (dc - p)*ratio + p;
}
// Round upper right corner
p = float2(extent.x+extent.z-s, extent.y+extent.w-s);
if (dc.x > p.x && dc.y > p.y) {
float2 d = abs(dc - p);
ratio = min(d.x,d.y)/max(d.x,d.y);
ratio = sqrt(1.0 + ratio*ratio);
return (dc - p)*ratio + p;
}
return dc;
}
I have two devices (iPod, iPhone), each using a different Apple ID. I have an existing game to which I'm adding TBM. When the iPod invites the iPhone, it sends an iMessage invite to the iPhone; when I click on that message, I get "Retrieving", then Game Center in Settings is opened, not my App (same version installed on both devices). I start my App on the iPhone and that match is not shown in the Matchmaker View Controller.
When I send an invite from the iPhone to the iPod and I click on the iMessage invite, the app starts but the match isn't listed in the MatchMaker ViewController on the iPod (but is on the iPhone).
In addition, when I click on the info circle on the iPhone, it who's the two players and "App Store" under the Game Center name. However, When I do the same on the iPod, it has a "Play your turn" there.
Any ideas?
Problem Summary
After upgrading to iOS 26.1 and 26.2, I'm experiencing a particle positioning bug in RealityKit where ParticleEmitterComponent particles render at an incorrect offset relative to their parent entity. This behavior does not occur on iOS 18.6.2 or earlier versions, suggesting a regression introduced in the newer OS builds.
Environment Details
Operating System: iOS 26.1 & iOS 26.2
Framework: RealityKit
Xcode Version: 16.2 (16C5032a)
Expected vs. Actual Behavior
Expected: Particles should render at the position of the entity to which the ParticleEmitterComponent is attached, matching the behavior on iOS 18.6.2 and earlier.
Actual: Particles appear away from their parent entity, creating a visual misalignment that breaks the intended AR experience.
Steps to Reproduce
Create or open an AR application with RealityKit that uses particle components
Attach a ParticleEmitterComponent to an entity via a custom system
Run the application on iOS 26.1 or iOS 26.2
Observe that particles render at an offset position away from the entity
Minimal Code Example
Here's the setup from my test case:
Custom Component & System:
struct SparkleComponent4: Component {}
class SparkleSystem4: System {
static let query = EntityQuery(where: .has(SparkleComponent4.self))
required init(scene: Scene) {}
func update(context: SceneUpdateContext) {
for entity in context.scene.performQuery(Self.query) {
// Only add once
if entity.components.has(ParticleEmitterComponent.self) { continue }
var newEmitter = ParticleEmitterComponent()
newEmitter.mainEmitter.color = .constant(.single(.red))
entity.components.set(newEmitter)
}
}
}
AR Setup:
let material = SimpleMaterial(color: .gray, roughness: 0.15, isMetallic: true)
let model = Entity()
model.components.set(ModelComponent(mesh: boxMesh, materials: [material]))
model.components.set(SparkleComponent4())
model.position = [0, 0.05, 0]
model.name = "MyCube"
let anchor = AnchorEntity(.plane(.horizontal, classification: .any, minimumBounds: [0.2, 0.2]))
anchor.addChild(model)
arView.scene.addAnchor(anchor)
Questions for the Community
Has anyone else encountered this particle positioning issue after updating to iOS 26.1/26.2?
Are there known workarounds or configuration changes to ParticleEmitterComponent that restore correct positioning?
Is this a confirmed bug, or could there be a change in coordinate system handling or transform inheritance that I'm missing?
Additional Information
I've already submitted this issue via Feedback Assistant(FB21346746)
App Storeにある『浮遊時計 Premium』は1Hzごとか10Hzごと、または3段階以上のリフレッシュレート計測はできますか?
Topic:
Graphics & Games
SubTopic:
General
I'm new to graphics and game design and I just wanted to know if a compute pipeline could be as efficient as a render pipeline for rasterization and an explanation on how and why. Also is it possible to manually perform rasterization with a render pipeline as in manipulate individual pixel data in a metal texture yourself but do it with a render pipeline?
I've coded a text-adventure game in SwiftUI. (My game has no graphics or sound effects.)
My app already supports keyboard navigation; I would like to add support for game controllers on iPhone. I can't figure out how to do it. I especially can't see any way to allow controller users to enter text in a TextField.
I've read https://developer.apple.com/documentation/gamecontroller/supporting-game-controllers and it's all about button events. There's no reference to SwiftUI at all in that documentation, or any input-method editing at all. The only mention of "keyboard" is about treating the keyboard itself as if it were a game controller providing button events.
How do I implement this?
Hi everyone,
I’ve been developing a custom, end-to-end 3D rendering engine called Crescent from scratch using C++20 and Metal-cpp (targeting macOS and visionOS). My primary goal is to build a zero-bottleneck, GPU-driven pipeline that maximizes the potential of Apple Silicon’s Unified Memory and TBDR architecture.
While the fundamental systems are stable, I am looking for architectural feedback from Metal framework engineers regarding specific synchronization and latency challenges.
Current Core Implementations:
GPU-Driven Instance Culling: High-performance occlusion culling using a Hierarchical Z-Buffer (HZB) approach via Compute Shaders.
Clustered Forward Shading: Support for high-count dynamic lights through view-space clustering.
Temporal Stability: Custom TAA with history rejection and Motion Blur resolve.
Asset Infrastructure: Robust GUID-based scene serialization and a JSON-driven ECS hierarchy.
The Architectural Challenge:
I am currently seeing slight synchronization overhead when generating the HZB mip-chain. On Apple Silicon, I am evaluating the cost of encoder transitions versus cache-friendly barriers.
&& m_hzbInitPipeline && m_hzbDownsamplePipeline && !m_hzbMipViews.empty();
if (canBuildHzb) {
MTL::ComputeCommandEncoder* hzbInit = commandBuffer->computeCommandEncoder();
hzbInit->setComputePipelineState(m_hzbInitPipeline);
hzbInit->setTexture(m_depthTexture, 0);
hzbInit->setTexture(m_hzbMipViews[0], 1);
if (m_pointClampSampler) {
hzbInit->setSamplerState(m_pointClampSampler, 0);
} else if (m_linearClampSampler) {
hzbInit->setSamplerState(m_linearClampSampler, 0);
}
const uint32_t hzbWidth = m_hzbMipViews[0]->width();
const uint32_t hzbHeight = m_hzbMipViews[0]->height();
const uint32_t threads = 8;
MTL::Size tgSize = MTL::Size(threads, threads, 1);
MTL::Size gridSize = MTL::Size((hzbWidth + threads - 1) / threads * threads,
(hzbHeight + threads - 1) / threads * threads,
1);
hzbInit->dispatchThreads(gridSize, tgSize);
hzbInit->endEncoding();
for (size_t mip = 1; mip < m_hzbMipViews.size(); ++mip) {
MTL::Texture* src = m_hzbMipViews[mip - 1];
MTL::Texture* dst = m_hzbMipViews[mip];
if (!src || !dst) {
continue;
}
MTL::ComputeCommandEncoder* downEncoder = commandBuffer->computeCommandEncoder();
downEncoder->setComputePipelineState(m_hzbDownsamplePipeline);
downEncoder->setTexture(src, 0);
downEncoder->setTexture(dst, 1);
const uint32_t mipWidth = dst->width();
const uint32_t mipHeight = dst->height();
MTL::Size downGrid = MTL::Size((mipWidth + threads - 1) / threads * threads,
(mipHeight + threads - 1) / threads * threads,
1);
downEncoder->dispatchThreads(downGrid, tgSize);
downEncoder->endEncoding();
}
if (m_instanceCullHzbPipeline) {
dispatchInstanceCulling(m_instanceCullHzbPipeline, true);
}
}
My Questions:
Encoder Synchronization: Would you recommend moving this loop into a single ComputeCommandEncoder using MTLBarrier between dispatches to maintain L2 cache residency, or is the overhead of separate encoders negligible for depth-downsampling on TBDR?
visionOS Bindless Latency: For stereo rendering on visionOS, what are the best practices for managing MTL4ArgumentTable updates at 90Hz+? I want to ensure that updating bindless resources for each eye doesn't introduce unnecessary CPU-to-GPU latency.
Memory Management: Are there specific hints for Memoryless textures that could be applied to intermediate HZB levels to save bandwidth during this process?
I’ve attached a screenshot of a scene rendered with the engine (PBR, SSR, and IBL).
In a Unity game, if the assetBundle.Unloadinterface is called very frequently during normal gameplay, it can cause the game application's screen to freeze, although the background music continues to play normally. This issue only occurs on iPhone 16 and iPhone 17 models, with no problems on lower-version phones. How can this problem be resolved?
Hello
If you add a ModelEntity to a world inside a portal, the drawing of the model will be occluded properly to the portal bounds.
However the invisible shape of the InputTargetComponent and CollisionComponent are not occluded. They are able to cross the portal, and if you have gestures on your ModelEntity you can trigger them in areas outside the portal bounds. This happens even if the ModelEntity has no PortalCrossingComponent.
Topic:
Graphics & Games
SubTopic:
RealityKit
I want to use reality to create a custom material that can use my own shader and support Mesh instancing (for rendering 3D Gaussian splating), but I found that CustomMaterial does not support VisionOS. Is there any other interface that can achieve my needs? Where can I find examples?
Topic:
Graphics & Games
SubTopic:
RealityKit