Sample CodevisionOSReviewed 2026-07-21View on Apple Developer

Playing spatial audio

At a glance

Item Summary
Purpose Create and adjust spatial audio in visionOS with RealityKit.
App architecture A Swift sample with the source-visible chain EntryPointSpatialAudioViewSwiftUI / RealityKit APIs.
Main patterns No named application pattern supported by the extracted structure
Project style 4 scanned source file(s) across Swift, organized around ranked entry, type, and file boundaries.
Execution model No structured execution marker indexed; callback threading requires source review.
State/event model Source-visible mechanisms: SwiftUI state property wrapper.
Key frameworks/packages SwiftUI, RealityKit; these are source dependencies, not architecture labels.

Project structure

Source bundle/
├── SpatialAudio/
│   ├── App/
│   │   ├── EntryPoint.swift
│   │   └── Info.plist
│   ├── Views/
│   │   ├── SpatialAudioView.swift
│   │   └── DecibelSlider.swift
│   └── Visualizer/
│       └── AxisVisualizer.swift
├── Configuration/
│   └── SampleCode.xcconfig
└── SpatialAudio.xcodeproj/
    ├── .xcodesamplecode.plist
    └── project.pbxproj

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 4 source declaration(s).

Overall architecture

Reference code

SpatialAudio/App/EntryPoint.swift:10 — architecture anchor

@main
struct EntryPoint: App {
    var body: some Scene {
        WindowGroup {
            SpatialAudioView()
        }
    }
}

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

Ownership evidence

SpatialAudio/Views/SpatialAudioView.swift:14 — stored dependency or nearest verified ownership anchor

struct SpatialAudioView: View {
    // ...
    let entity = Entity()
    // ...
}
Owner Object or state Relationship Mutation authority
SpatialAudioView Entity (entity) creates and retains Initialized by the owner; the binding is immutable
SpatialAudioView Decibel (gain) owns wrapper-managed state Owning lexical scope
SpatialAudioView Decibel (directLevel) owns wrapper-managed state Owning lexical scope
SpatialAudioView Decibel (reverbLevel) owns wrapper-managed state Owning lexical scope

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.

No source-visible execution, scheduling, or synchronization boundary was found in the indexed source.

@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.

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.

Category Mechanism or module Verified role Evidence
State propagation SwiftUI state property wrapper A SwiftUI property wrapper supplies or observes UI state. SpatialAudio/Views/SpatialAudioView.swift:17
Source import SwiftUI The cited file imports this module; runtime use and architectural role are not inferred. SpatialAudio/App/EntryPoint.swift:8
Source import RealityKit The cited file imports this module; runtime use and architectural role are not inferred. SpatialAudio/Views/SpatialAudioView.swift:9

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

SpatialAudio/Views/SpatialAudioView.swift:12 — representative type boundary

struct SpatialAudioView: View {
    // ...
    let entity = Entity()
    // ...
}
Type Responsibility Depends on or conforms to
SpatialAudioView User-interface presentation and input forwarding View
EntryPoint Represents a feature value or composable behavior App
DecibelSlider Represents a feature value or composable behavior View
AxisVisualizer Represents a feature value or composable behavior Concrete collaborators/imported frameworks

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

Access control

Symbol Access Verified effect Likely rationale
gain (SpatialAudio/Views/SpatialAudioView.swift:17) private Use is restricted to the lexical declaration and same-file extensions allowed by Swift. Inference: keep state mutation or dependency lifetime inside the owning implementation.
directLevel (SpatialAudio/Views/SpatialAudioView.swift:20) private Use is restricted to the lexical declaration and same-file extensions allowed by Swift. Inference: keep state mutation or dependency lifetime inside the owning implementation.
reverbLevel (SpatialAudio/Views/SpatialAudioView.swift:23) private Use is restricted to the lexical declaration and same-file extensions allowed by Swift. Inference: keep state mutation or dependency lifetime inside the owning implementation.
DecibelSlider (SpatialAudio/Views/DecibelSlider.swift:8) implicit internal No explicit modifier means the Swift declaration is internal to the module. Inference: app-target collaboration needs no exported library surface.

Reference code

SpatialAudio/Views/SpatialAudioView.swift:17 — representative boundary

struct SpatialAudioView: View {
    // ...
    @State private var gain: Audio.Decibel = .zero
    // ...
}

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

Logic Owning type or file Placement rationale
User-interface presentation and input forwarding SpatialAudioView The source’s View suffix makes this role explicit.

Design patterns

Pattern Source evidence Purpose or tradeoff
No named application pattern SpatialAudio/App/EntryPoint.swift:10 The verified source directly composes concrete framework types; this document avoids forcing a pattern name.

Naming conventions

  • Types: View: SpatialAudioView.
  • Protocols: no local protocol declaration in the scanned source.
  • Methods: make.
  • Files: SpatialAudio/App/EntryPoint.swift, SpatialAudio/Views/SpatialAudioView.swift, SpatialAudio/Views/DecibelSlider.swift, SpatialAudio/Visualizer/AxisVisualizer.swift.

Architecture takeaways

  • EntryPoint is the main source-visible entry or composition anchor for this sample.
  • Framework work reaches SwiftUI, 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

Source file Relevant symbols
SpatialAudio/App/EntryPoint.swift Cited implementation, SwiftUI, EntryPoint
SpatialAudio/Views/SpatialAudioView.swift Cited implementation, SpatialAudioView, SwiftUI state property wrapper, RealityKit
SpatialAudio/Views/DecibelSlider.swift DecibelSlider
SpatialAudio/Visualizer/AxisVisualizer.swift AxisVisualizer