Mixing spatial music

At a glance

Project structure

Source bundle/
└── MixingSpatialMusic/
    ├── MixingSpatialMusicApp.swift
    ├── AppModel.swift
    ├── ECS/
    │   ├── ReverbMeshLoader.swift
    │   └── ViewpointComponent.swift
    ├── Views/
    │   ├── AudioMixer/
    │   │   ├── MixerView.swift
    │   │   ├── TrackView.swift
    │   │   ├── LabeledFader.swift
    │   │   └── MuteSolo.swift
    │   ├── ImmersiveView.swift
    │   └── SettingsView.swift
    ├── Logger.swift
    └── Model/
        └── AudioStem.swift

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 21 source declaration(s).

Overall architecture

flowchart LR
    N1["MixingSpatialMusicApp"]
    N2["SettingsView"]
    N3["AppModel"]
    N4["ReverbMeshLoader"]
    N5["RealityKit APIs"]
    N1 --> N2
    N2 --> N3
    N3 --> N4
    N4 --> N5

Reference code

MixingSpatialMusic/MixingSpatialMusicApp.swift:10 — architecture anchor

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

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 RealityKit.

Ownership and state

classDiagram
    MixingSpatialMusicApp *-- AppModel : appModel
    AppModel *-- Entity : root
    AppModel *-- Entity : audioSourcesRoot
    AppModel o-- PlaybackState : playbackState

Ownership evidence

MixingSpatialMusic/MixingSpatialMusicApp.swift:13 — stored dependency or nearest verified ownership anchor

@main
struct MixingSpatialMusicApp: 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

MixingSpatialMusic/AppModel.swift:12 — representative execution boundary

@MainActor
@Observable
class AppModel {
    // ...
    var immersiveSpaceState = ImmersiveSpaceState.closed
    // ...
}

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

MixingSpatialMusic/MixingSpatialMusicApp.swift:11 — representative type boundary

@main
struct MixingSpatialMusicApp: 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

MixingSpatialMusic/AppModel.swift:102 — representative boundary

    private func addViewpoints() {
        for viewpoint in Viewpoint.all {
            root.addChild(.makeViewpoint(viewpoint))
        }
    }

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: MixingSpatialMusicApp; Component: ViewpointComponent; Loader: ReverbMeshLoader; Model: AppModel, VisualModel; View: ImmersiveView, MixerView, SettingsView, TrackView.
• Protocols: no local protocol declaration in the scanned source.
• Methods: teleportToStartingViewpoint, teleport, loadVisualEnvironment, loadAudioEnvironment, loadAudio, addViewpoints, configureAudioMixGroups, makeAudioSource.
• Files: MixingSpatialMusic/MixingSpatialMusicApp.swift, MixingSpatialMusic/AppModel.swift, MixingSpatialMusic/ECS/ReverbMeshLoader.swift, MixingSpatialMusic/ECS/ViewpointComponent.swift, MixingSpatialMusic/Views/AudioMixer/MixerView.swift, MixingSpatialMusic/Views/AudioMixer/TrackView.swift.

Architecture takeaways

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