Animating hand models in visionOS

At a glance

Project structure

Source bundle/
├── AnimatingHandModels/
│   ├── AnimatingHandModelsApp.swift
│   ├── AppModel.swift
│   ├── ContentView.swift
│   ├── ImmersiveView.swift
│   ├── ToggleImmersiveSpaceButton.swift
│   └── Info.plist
├── AnimatingHandModels.xcodeproj/
│   ├── .xcodesamplecode.plist
│   └── project.pbxproj
└── Configuration/
    └── SampleCode.xcconfig

Structure observations

• Architecturally prominent files are ranked from entry points and role-named declarations; resource-only paths are omitted.
• Primary languages: Swift.
• The verified tree contains 4 project/configuration file(s) and 6 source declaration(s).

Overall architecture

flowchart LR
    N1["AnimatingHandModelsApp"]
    N2["ContentView"]
    N3["AppModel"]
    N4["SwiftUI / ARKit APIs"]
    N1 --> N2
    N2 --> N3
    N3 --> N4

Reference code

AnimatingHandModels/AnimatingHandModelsApp.swift:10 — architecture anchor

@main
struct AnimatingHandModelsApp: App {
    @State private var appModel = AppModel()

    var body: some Scene {
        WindowGroup {
            ContentView()
                .environment(appModel)
                .task {
                    await appModel.observeHandTrackingAuthorizationStatus()
                }
        }

        ImmersiveSpace(id: appModel.immersiveSpaceID) {
            ImmersiveView()
                .environment(appModel)
                .onAppear {
                    appModel.immersiveSpaceState = .open
                }
                .onDisappear {
                    appModel.immersiveSpaceState = .closed
                }
        }
        .immersionStyle(selection: .constant(.full), in: .full)
        .upperLimbVisibility(.hidden)
    }
}

Interpretation

The arrows summarize the source-visible entry, role-named types or folders, and framework direction; when nodes come from structural folders, the sequence is a high-level interpretation rather than proof that every adjacent node calls the next. Ownership is claimed only where the next section cites a stored property or assignment. The diagram is intentionally limited to the dominant path into visionOS.

Ownership and state

classDiagram
    AnimatingHandModelsApp *-- AppModel : appModel
    AppModel o-- AuthorizationStatus : handTrackingAuthorizationStatus
    ImmersiveView *-- ARKitSession : arkitSession
    ImmersiveView *-- HandTrackingProvider : handTrackingProvider

Ownership evidence

AnimatingHandModels/AnimatingHandModelsApp.swift:12 — stored dependency or nearest verified ownership anchor

@main
struct AnimatingHandModelsApp: App {
    @State private var appModel = AppModel()
    // ...
}

Composition arrows indicate a source-visible construction expression or locally owned value state; aggregation means the owner stores or receives a dependency without proving exclusive lifetime ownership.

Concurrency, scheduling, and thread safety

Evidence limit: actor isolation, async/await, or Task creation does not by itself prove background-thread execution; Sendable conformance alone does not prove thread-safe mutation.

@MainActor/MainActor.run, DispatchQueue.main, and RunLoop.main are reported as distinct isolation, queue, and event-loop mechanisms. A plain Task is kept separate from Task.detached; neither is labeled as a background thread.

Reference code

AnimatingHandModels/AnimatingHandModelsApp.swift:19 — representative execution boundary

@main
struct AnimatingHandModelsApp: App {
    // ...
                    await appModel.observeHandTrackingAuthorizationStatus()
    // ...
}

State propagation, frameworks, and dependencies

Evidence limit: an import proves a source-level compilation dependency at the cited line; it does not prove runtime use, architectural adoption, or whether a Swift package is a direct application dependency.

receive(on:) describes downstream delivery scheduling, while subscribe(on:) describes upstream subscription/request/cancel scheduling. An import Combine alone establishes neither behavior nor a Store, reducer, Redux, or other application architecture.

Class and protocol design

AnimatingHandModels/AnimatingHandModelsApp.swift:11 — representative type boundary

@main
struct AnimatingHandModelsApp: App {
    @State private var appModel = AppModel()
    // ...
}

No local protocol conformance is claimed as protocol-oriented design; external framework conformances are listed only as dependencies.

Access control

Reference code

AnimatingHandModels/AnimatingHandModelsApp.swift:12 — representative boundary

@main
struct AnimatingHandModelsApp: App {
    @State private var appModel = AppModel()
    // ...
}

Swift declarations without a modifier are internal; explicit private, fileprivate, private(set), public, or open entries above are interpreted by language semantics. Objective-C/C samples instead rely on header and implementation boundaries, which are not equivalent to Swift lexical privacy.

Logic ownership and placement

Design patterns

Naming conventions

• Types: App: AnimatingHandModelsApp; Model: AppModel; View: ContentView, ImmersiveView.
• Protocols: no local protocol declaration in the scanned source.
• Methods: observeHandTrackingAuthorizationStatus, loadGloveModel, startHandTracking, updateGlovesFromHandAnchors, updateJointRotations.
• Files: AnimatingHandModels/AnimatingHandModelsApp.swift, AnimatingHandModels/AppModel.swift, AnimatingHandModels/ContentView.swift, AnimatingHandModels/ImmersiveView.swift, AnimatingHandModels/ToggleImmersiveSpaceButton.swift.

Architecture takeaways

• AnimatingHandModelsApp is the main source-visible entry or composition anchor for this sample.
• Framework work reaches SwiftUI, ARKit, RealityKit through a deliberately small high-level chain; the detailed API graph remains inside the cited implementation files.
• Stored-property evidence identifies lifecycle collaboration; it does not by itself prove exclusive object ownership.
• Access-control conclusions separate verified language visibility from the likely design rationale.
• The source does not justify labeling the design protocol-oriented.

Source map

• Official Apple documentation