Hi,
The metal-cpp distribution appears to only contain headers for Foundation and Quartzcore. The LearnMetalCPP download [1] provides a ZIP with an metal-cpp-extensions directory containing AppKit.hpp and MetalKit.hpp headers. First question: Are these headers distributed anywhere else more publicly? Without these headers only the renderer can be fully written in C++ as far as I can tell, i.e. no complete C++ NSApplication. Second question: Will these headers, if needed, be maintained (e.g. updated and/or extended) by Apple along side metal-cpp?
[1] https://developer.apple.com/metal/cpp/
Thank you and regards.
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On an iPad running iPadOS 26 beta 4, when tapping the Game Center Access Point, the overlay doesn’t show the configured achievements, leaderboards or challenges.
I should specify this is an in-development app and the achievements and leaderboards are in the “Not Live” state, however they show on other devices running iOS 18 in the Access Point UI.
Anyone else having this issue? If so, how should I test achievements and leaderboards while iOS 26 beta is out?
The UI looks like this on iPadOS 26:
I work on a team that provides an SDK for another game to handle various tasks like authentication. They are experiencing a case where devices using iOS 17 are failing to authenticate with GameCenter, receiving the message "The requested operation could not be completed because local player has not been authenticated." We imagine this is because they still have some setup to finish regarding GameCenter itself, and we're working with them to take care of that.
However, on iOS 18, their app ends up waiting indefinitely for GameCenter authentication messages that it never receives. That's where we're puzzled. We expect them to have the same outcome regardless of OS version.
We initiate GameCenter authentication by setting an authenticateHandler after some initial application setup. The handler has code to account for UI, errors, and successful authentication.
On iOS 17, it's clear that it's getting called as expected because they receive an indication that the player isn't authenticated. But on iOS 18, it looks like the same handler code on iOS 18 isn't being called at all. Are there differences in how iOS 18 interacts with the authenticationHandler that we somehow aren't accounting for? Or is there potentially something else that we're doing incorrectly that is manifesting only on iOS 18?
Here's a simplified version of our login function code (in Obj-C++). There is no OS-specific code, and the job that owns this function does stay in scope until after authentication is complete.
void beginLogin()
{
// Snip: Check if the user is already logged in.
// Snip: Prevent multiple concurrent calls to this function.
auto authenticateHandler = ^(UIViewController* gcViewController, NSError* error)
{
if (gcViewController != nil)
{
// Snip: Display the UI
}
else if (error != nil)
{
// Snip: Handle the error.
}
else
{
if ([[GKLocalPlayer localPlayer] isAuthenticated])
{
// Snip: Handle successful authentication.
}
else
{
// Snip: Handle other case.
}
}
};
[[GKLocalPlayer localPlayer] setAuthenticateHandler: authenticateHandler];
}
When previewing the recording of gameplay the buttons to exit or save are unclickable behind the top bar clock and Wi-Fi/5G status bar. Which means that you have to quit the game in order to continue.
Tested on multiple devices.
Does anyone have a solution to this? At the moment we have disabled it altogether for iOS 26 users.
I'm new here so I don't know what's this function belongs to which topic... Sorry about that!
I watched the WWDC stream and I am really interested in this function, I'm wondering if this function could be used in my apps.
I looked up the document but I find it only support visionOS(i'm not sure about that, but I saw the demo is base on the visionOS)
I have 2 planes with textures on. I want these planes to intersect [ –|– ], and I want the blend mode to be additive. Currently I get z fighting on the planes, and I can't see how to set blend modes.
I've done this before in Unity and Godot in a fairly straight forward manner.
How do I accomplish this with RealityKit, preferably using code only (my scene is quite dynamic)?
Do I need to do it with a shader manually? How can I stop the z fighting?
Hi everyone,
I'm new to visionOS development. I'm trying to create a physics-based scene (with gravity) where users can pick up and move objects on a workbench. I am struggling with physics interactions during the drag gesture:
Kinematic Mode: If I switch to .kinematic during the drag, the object moves smoothly but clips through other objects (no collisions).
Dynamic Mode: I tried keeping it .dynamic and applying linear velocity toward the hand position, but the movement feels laggy and unresponsive.
Hybrid Approach: I tried switching to .kinematic during DragGesture.onChange and back to .dynamic on collision, but this causes the entity to jitter/shake violently when touching other objects.
Has anyone found a clean way to drag objects while maintaining solid collisions.
Thanks for your help!
Hi,
How to enable multitouch on ARView?
Touch functions (touchesBegan, touchesMoved, ...) seem to only handle one touch at a time. In order to handle multiple touches at a time with ARView, I have to either:
Use SwiftUI .simultaneousGesture on top of an ARView representable
Position a UIView on top of ARView to capture touches and do hit testing by passing a reference to ARView
Expected behavior:
ARView should capture all touches via touchesBegan/Moved/Ended/Cancelled.
Here is what I tried, on iOS 26.1 and macOS 26.1:
ARView Multitouch
The setup below is a minimal ARView presented by SwiftUI, with touch events handled inside ARView. Multitouch doesn't work with this setup.
Note that multitouch wouldn't work either if the ARView is presented with a UIViewController instead of SwiftUI.
import RealityKit
import SwiftUI
struct ARViewMultiTouchView: View {
var body: some View {
ZStack {
ARViewMultiTouchRepresentable()
.ignoresSafeArea()
}
}
}
#Preview {
ARViewMultiTouchView()
}
// MARK: Representable ARView
struct ARViewMultiTouchRepresentable: UIViewRepresentable {
func makeUIView(context: Context) -> ARView {
let arView = ARViewMultiTouch(frame: .zero)
let anchor = AnchorEntity()
arView.scene.addAnchor(anchor)
let boxWidth: Float = 0.4
let boxMaterial = SimpleMaterial(color: .red, isMetallic: false)
let box = ModelEntity(mesh: .generateBox(size: boxWidth), materials: [boxMaterial])
box.name = "Box"
box.components.set(CollisionComponent(shapes: [.generateBox(width: boxWidth, height: boxWidth, depth: boxWidth)]))
anchor.addChild(box)
return arView
}
func updateUIView(_ uiView: ARView, context: Context) { }
}
// MARK: ARView
class ARViewMultiTouch: ARView {
required init(frame: CGRect) {
super.init(frame: frame)
/// Enable multi-touch
isMultipleTouchEnabled = true
cameraMode = .nonAR
automaticallyConfigureSession = false
environment.background = .color(.gray)
/// Disable gesture recognizers to not conflict with touch events
/// But it doesn't fix the issue
gestureRecognizers?.forEach { $0.isEnabled = false }
}
required dynamic init?(coder decoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
for touch in touches {
/// # Problem
/// This should print for every new touch, up to 5 simultaneously on an iPhone (multi-touch)
/// But it only fires for one touch at a time (single-touch)
print("Touch began at: \(touch.location(in: self))")
}
}
}
Multitouch with an Overlay
This setup works, but it doesn't seem right. There must be a solution to make ARView handle multi touch directly, right?
import SwiftUI
import RealityKit
struct MultiTouchOverlayView: View {
var body: some View {
ZStack {
MultiTouchOverlayRepresentable()
.ignoresSafeArea()
Text("Multi touch with overlay view")
.font(.system(size: 24, weight: .medium))
.foregroundStyle(.white)
.offset(CGSize(width: 0, height: -150))
}
}
}
#Preview {
MultiTouchOverlayView()
}
// MARK: Representable Container
struct MultiTouchOverlayRepresentable: UIViewRepresentable {
func makeUIView(context: Context) -> UIView {
/// The view that SwiftUI will present
let container = UIView()
/// ARView
let arView = ARView(frame: container.bounds)
arView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
arView.cameraMode = .nonAR
arView.automaticallyConfigureSession = false
arView.environment.background = .color(.gray)
let anchor = AnchorEntity()
arView.scene.addAnchor(anchor)
let boxWidth: Float = 0.4
let boxMaterial = SimpleMaterial(color: .red, isMetallic: false)
let box = ModelEntity(mesh: .generateBox(size: boxWidth), materials: [boxMaterial])
box.name = "Box"
box.components.set(CollisionComponent(shapes: [.generateBox(width: boxWidth, height: boxWidth, depth: boxWidth)]))
anchor.addChild(box)
/// The view that will capture touches
let touchOverlay = TouchOverlayView(frame: container.bounds)
touchOverlay.autoresizingMask = [.flexibleWidth, .flexibleHeight]
touchOverlay.backgroundColor = .clear
/// Pass an arView reference to the overlay for hit testing
touchOverlay.arView = arView
/// Add views to the container.
/// ARView goes in first, at the bottom.
container.addSubview(arView)
/// TouchOverlay goes in last, on top.
container.addSubview(touchOverlay)
return container
}
func updateUIView(_ uiView: UIView, context: Context) {
}
}
// MARK: Touch Overlay View
/// A UIView to handle multi-touch on top of ARView
class TouchOverlayView: UIView {
weak var arView: ARView?
override init(frame: CGRect) {
super.init(frame: frame)
isMultipleTouchEnabled = true
isUserInteractionEnabled = true
}
required init?(coder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
let totalTouches = event?.allTouches?.count ?? touches.count
print("--- Touches Began --- (New: \(touches.count), Total: \(totalTouches))")
for touch in touches {
let location = touch.location(in: self)
/// Hit testing.
/// ARView and Touch View must be of the same size
if let arView = arView {
let entity = arView.entity(at: location)
if let entity = entity {
print("Touched entity: \(entity.name)")
} else {
print("Touched: none")
}
}
}
}
override func touchesCancelled(_ touches: Set<UITouch>, with event: UIEvent?) {
let totalTouches = event?.allTouches?.count ?? touches.count
print("--- Touches Cancelled --- (Cancelled: \(touches.count), Total: \(totalTouches))")
}
}
Imagine a native macOS app that acts as a "launcher" for a Java game.** For example, the "launcher" app might use the Swift Process API or a similar method to run the java command line tool (lets assume the user has installed Java themselves) to run the game.
I have seen How to Enable Game Mode. If the native launcher app's Info.plist has the following keys set:
LSApplicationCategoryType set to public.app-category.games
LSSupportsGameMode set to true (for macOS 26+)
GCSupportsGameMode set to true
The launcher itself can cause Game Mode to activate if the launcher is fullscreened. However, if the launcher opens a Java process that opens a window, then the Java window is fullscreened, Game Mode doesn't seem to activate. In this case activating Game Mode for the launcher itself is unnecessary, but you'd expect Game Mode to activate when the actual game in the Java window is fullscreened.
Is there a way to get Game Mode to activate in the latter case?
** The concrete case I'm thinking of is a third-party Minecraft Java Edition launcher, but the issue can also be demonstrated in a sample project (FB13786152). It seems like the official Minecraft launcher is able to do this, though it's not clear how. (Is its bundle identifier hardcoded in the OS to allow for this? Changing a sample app's bundle identifier to be the same as the official Minecraft launcher gets the behavior I want, but obviously this is not a practical solution.)
Hello — I shipped an App Store build that signs in to Game Center using the Apple Unity Plugins (GameKit). The login banner appears, but my app still doesn’t show up in Game Center’s “All activity” (You started playing XXX 2d ago)
What I’ve done
Call await GKLocalPlayer.Authenticate();
“Game Center” is enabled for the current version in App Store Connect
Confirmed: other App Store games do appear under “All Activity” on the same device/account
Timeline: This is the first version that enables Game Center (not the app’s first release), and it has been about 2 hours since this build went live.
Questions
Is authentication alone sufficient for “Recently Played,” or is at least one Game Center component (leaderboards, achievements, activities, multiplayer) required?
Is there a typical propagation delay before “Recently Played” starts showing a newly enabled app/version?
Is there anything else I should configure in App Store Connect or entitlements to make “Recently Played” visible?
Thanks for any help.
Hey everyone,
I’m trying to run Kingdom Come: Deliverance 2 using the Game Porting Toolkit, but I’m encountering a black screen when launching the game. From what I know about the game’s requirements, it might be using Shader Model 6.5, which supports advanced features like DirectX Raytracing (DXR) Tier 1.1. This leads me to suspect that the issue could be related to missing support for DirectX 12.1 Features or Shader Model 6.5 in GPTK.
Does anyone know if these features are currently supported by GPTK? If not, are there any plans to implement them in future updates? Alternatively, is there any workaround for games that rely on Shader Model 6.5 and ray tracing?
Thanks a lot for your help!
I have a 3D model with morphing animation that works correctly in Blender.
I exported this model as a USDZ file and tried to display it in an Xcode-developed visionOS app, but the morphing animation does not play.
What I Have Tried:
Morphing animation works correctly in Blender.
After exporting to USDZ, the morphing animation does not play in the Xcode app.
Linear motion animations (such as object movement) work fine.
Behavior in Reality Converter:
GLB files do not display.
USDZ files load, but morphing animations do not play.
What I Want to Know:
Is there a way to play morphing animations in an Xcode-developed app?
Does RealityKit support morphing animations?
Can morphing animations be played in an Xcode-developed app?
If RealityKit does not support morphing animations, what alternative methods can be used to play them?
I am looking for a way to use the existing animations without recreating them.
Additional Information:
I have both the Blender file (where animations work) and the USDZ file (where animations do not play).
I am developing a visionOS app using Xcode.
Any advice or solutions would be greatly appreciated.
Thank you in advance!
Hello,
In our game we enforce an age gate before showing Game Center sign‑in. Only after the user passes the age gate do we call GKLocalPlayer.localPlayer.authenticateHandler.
The reason I’m asking is that we want to reliably detect if the game was launched from a Game Center activity in the Games app (iOS 26+). If the user prefers to enter via activities, we don’t want to miss that event during cold start.
Our current proposal is:
Register a GKLocalPlayerListener early in didFinishLaunchingWithOptions: so the app is ready to catch events.
Queue any incoming events in our dispatcher.
Only process those events after the user passes the age gate and authentication succeeds.
My questions are:
Does player:wantsToPlayGameActivity:completionHandler: ever fire before authentication, or only after the local player is authenticated?
If it only fires after authentication, is our “register early but gate processing” approach the correct way to ensure we don’t miss activity launches?
Is there any recommended pattern to distinguish “activity launch” vs. “normal launch” in this age‑gate scenario?
We want to respect Apple’s age gate requirements, but also ensure activity launches are not lost if the user prefers that entry point.
Sorry if this is a stupid question — I just want to be sure we’re following the right pattern.
Thanks for any clarification or best‑practice guidance!
Issue
When an Entity with a ViewAttachmentComponent is:
disabled using isEnabled = false
removed using removeFromParent()
and then enabled or added back again, the attached SwiftUI view is rendered correctly, but tap interactions stop working.
Specifically:
Button actions inside the attached view do not fire
TapGesture closures on child views do not respond
Expected Behavior
Tap interactions inside the attached view should continue to work after the Entity is re-enabled or re-added.
Actual Behavior
After being disabled or removed once, all tap interactions stop responding.
Comparison
When displaying the same SwiftUI view using RealityViewAttachments, this issue does not occur.
Removing and re-displaying the attachment still allows taps to work correctly.
Reproduction
Attached sample code reproduces the issue:
A RealityView with an Entity that has a ViewAttachmentComponent
The attached SwiftUI view contains a Toggle
The toggle updates isEnabled on the Entity
After toggling off and on, tap interactions stop responding
Environment
Xcode 26
visionOS 26
Question
Is this expected behavior of ViewAttachmentComponent, or a bug?
Is there a recommended way to temporarily hide or disable an Entity with ViewAttachmentComponent without breaking tap interactions?
import SwiftUI
import RealityKit
struct GestureTestView: View {
@State var sampleEnabled = true
@State var sampleEntity: Entity?
var body: some View {
RealityView { contents, attachments in
// After deleting and re-displaying it, taps no longer respond.
let sample = Entity(components: ViewAttachmentComponent(rootView: SampleView()))
// Executed successfully
//let sample = attachments.entity(for: "SampleView")!
contents.add(sample)
sample.position = [0, 1.2, -1]
sampleEntity = sample
let toggleButton = Entity(components: ViewAttachmentComponent(rootView: ToggleButtonView(isOn: $sampleEnabled)))
contents.add(toggleButton)
toggleButton.position = [0, 1, -1]
} update: { _, _ in
// run update closure
print(sampleEnabled)
// update sample entity enable
sampleEntity?.isEnabled = sampleEnabled
} attachments: {
Attachment(id: "SampleView") {
SampleView()
}
}
}
}
struct ToggleButtonView: View {
@Binding var isOn: Bool
var body: some View {
VStack {
Toggle(isOn: $isOn) {
Text("Toggle")
}
}
.padding()
.glassBackgroundEffect()
}
}
struct SampleView: View {
var body: some View {
VStack {
Button {
print("Hello, World!")
} label: {
Text("Hello, World!")
.padding()
}
}
.padding()
.glassBackgroundEffect()
}
}
#Preview(immersionStyle: .mixed) {
GestureTestView()
}
Hi,
I'm rewriting my game from SceneKit to RealityKit, and I'm having trouble implementing the following scenario:
I tap on the iPhone screen to select an Entity that I want to drag.
If an Entity was tapped, it should then be possible to drag it left, right, etc.
SceneKit solution:
func CGPointToSCNVector3(_ view: SCNView, depth: Float, point: CGPoint) -> SCNVector3 {
let projectedOrigin = view.projectPoint(SCNVector3Make(0, 0, Float(depth)))
let locationWithz = SCNVector3Make(Float(point.x), Float(point.y), Float(projectedOrigin.z))
return view.unprojectPoint(locationWithz)
}
and then I was calling:
SCNView().hitTest(location, options: [SCNHitTestOption.firstFoundOnly:true])
the code was called inside of the UIPanGestureRecognizer in my UIViewController.
Could I reuse that code or should I go with the SwiftUI approach - something like that:
var body: some View {
RealityView {
....
} .gesture(TapGesture().onEnded {
})
?
I already have this code:
@State private var location: CGPoint?
.onTapGesture { location in
self.location = location
}
I'm trying to identify the entity that was tapped within the RealityView like that:
RealityView { content in
let box: ModelEntity = createBox() // for now there is only one box, however there will be many boxes
content.add(box)
let anchor = AnchorEntity(world: [0, 0, 0])
content.add(anchor)
_ = content.subscribe(to: SceneEvents.Update.self) { event in
//TODO: find tapped entity, so that it could be dragged inside of the DragGesture()
}
Any help would be appreciated.
I also noticed that if I create a TapGesture like that:
TapGesture(count: 1)
.targetedToAnyEntity()
and add it to my view using .gesture() then it is not triggered.
Code is download from apple official metal4 sample
[https://developer.apple.com/documentation/metal/drawing-a-triangle-with-metal-4?language=objc]
enable metal gpu trace in macOS schema and trace a frame in Xcode.
Xcode may show segment fault on App from some 'GTTrace' function when click trace button.
When replay a .gputrace file, Xcode may crash , throw an internal error or a XPC error.
The example code using old metal-renderer can trace without any problem and everything works fine.
Test Environment:
Xcode Version 26.2 (17C52)
macOS 26.2 (25C56)
M1 Pro 16GB A2442
I have something like this drawing in an MTKView (see at bottom).
I am finding it difficult to figure out when can the Swift-land resources used in making the MTLBuffer(s) be released? Below, for example, is it ok if args goes out of scope (or is otherwise deallocated) at point 1, 2, or 3? Or perhaps even earlier, as soon as argsBuffer has been created?
I have been reading through various articles such as
Setting resource storage modes
Choosing a resource storage mode for Apple GPUs
Copying data to a private resource
but it's a lot to absorb and I haven't been really able to find an authoritative description of the required lifetime of the resources in CPU land.
I should mention that this is Metal 4 code. In previous versions of Metal, the MTLCommandBuffer had the ability to add a completion handler to be called by the GPU after it has finished running the commands in the buffer but in Metal 4 there is no such thing (it it were even needed for the purpose I am interested in).
Any advice and/or pointers to the definitive literature will be appreciated.
guard let argsBuffer = device.makeBuffer(bytes: &args,...
argumentTable.setAddress(argsBuffer.gpuAddress, ...
encoder.setArgumentTable(argumentTable, stages: .vertex)
// encode drawing
renderEncoder.draw...
...
encoder.endEncoding() // 1
commandBuffer.endCommandBuffer() // 2
commandQueue.waitForDrawable(drawable)
commandQueue.commit([commandBuffer]) // 3
commandQueue.signalDrawable(drawable)
drawable.present()
Topic:
Graphics & Games
SubTopic:
Metal
There is a sample project from Apple here. It has a scene of a city at night and you can move in it.
It basically has 2 parts:
application code written in what looks like Objective-C (I am more familiar with C++), which inherits from things like NSObject, MTKView, NSViewController and so on - it processes input and all app-related and window-related stuff.
rendering code that also looks like Objective-C. Btw both parts are mostly in .mm files (Obj-C++ AFAIK). The application part directly uses only one class from the rendering part - AAPLRenderer.
I want to move the rendering part to C++ using metal-cpp. For that I need to link metal-cpp to the project. I did it successfully with blank projects several times before using this tutorial. But with this sample project Xcode can't find Foundation/Foundation.hpp (and other metal-cpp headers). The error says this:
Did not find header 'Foundation.hpp' in framework 'Foundation' (loaded from '/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX15.0.sdk/System/Library/Frameworks')
Pls help
Post can be removed.
How to create a beautiful fire animation using Swift?
Which API is better to use?