Docking a video player in an immersive scene

At a glance

Project structure

Source bundle/
├── Models/AVPlayerViewModel.swift  # AVPlayerViewModel
├── Views/AVPlayerView.swift  # AVPlayerView
├── App/DockingApp.swift  # DockingApp
├── Models/AppModel.swift  # AppModel, ImmersiveSpaceState
├── Views/ContentView.swift  # ContentView
├── Views/ImmersivePickerView.swift  # ImmersivePickerView
├── Views/ImmersiveView.swift  # ImmersiveView
└── Packages/RealityKitContent/Package.realitycomposerpro/ProjectData/main.json  # authored RealityKit content

Structure observations

• The runtime boundary is WindowGroup + ImmersiveSpace; the tree is pruned to lifecycle, state, framework, rendering, and ECS files.
• The source is Swift; its compact size does not erase any explicit owner shown below.
• Authored .reality, .rkassets, or Reality Composer Pro content is an implementation boundary; Swift loads or drives it rather than reproducing its entity graph.

Overall architecture

flowchart LR
    DockingApp_1["DockingApp"]
    WindowGroup___ImmersiveSpace_2["WindowGroup + ImmersiveSpace"]
    AVPlayerView_3["AVPlayerView"]
    AVPlayerViewModel_4["AVPlayerViewModel"]
    RealityKit_entity_graph_5["RealityKit entity graph"]
    AVPlayer___RealityKit_presentation_6["AVPlayer + RealityKit presentation"]
    DockingApp_1 --> WindowGroup___ImmersiveSpace_2
    WindowGroup___ImmersiveSpace_2 --> AVPlayerView_3
    AVPlayerView_3 --> AVPlayerViewModel_4
    AVPlayerViewModel_4 --> RealityKit_entity_graph_5
    RealityKit_entity_graph_5 --> AVPlayer___RealityKit_presentation_6

Reference code

App/DockingApp.swift:11 — executable or app-lifecycle anchor.

struct DockingApp: App {
    // ...
}

The diagram is a responsibility flow, not a claim that every adjacent node directly calls the next. It separates lifecycle, presentation, stable state, framework/session work, and the RealityKit entity graph.

Ownership and state

classDiagram
    AVPlayerViewModel --> AVPlayerViewController : avPlayerViewController
    AVPlayerViewModel *-- AVPlayer : avPlayer
    DockingApp *-- AppModel : appModel
    DockingApp *-- AVPlayerViewModel : avPlayerViewModel

Ownership evidence

Models/AVPlayerViewModel.swift:14 — representative stored state or nearest verified lifecycle anchor.

@MainActor
@Observable
class AVPlayerViewModel: NSObject {
    // ...
    private var avPlayerViewController: AVPlayerViewController?
    // ...
}

Ownership is intentionally narrow: environment, bindings, observed objects, weak links, and delegate callbacks do not prove lifetime ownership. Initialized stored services and wrapper-managed state do; entities added inside a RealityKit content closure belong to that entity graph.

Class and protocol design

The reviewed source defines no local substitution protocol. Its App, View, delegate, renderer, ARKit, and RealityKit conformances are framework-facing contracts, so this document does not label the whole app protocol-oriented.

Access control

No reviewed Swift access example uses fileprivate, private(set), open; declarations without a modifier are internal.

Reference code

App/DockingApp.swift:13 — representative visibility boundary.

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

Logic ownership and placement

Design patterns

Naming conventions

• Role suffixes are evidence, not decoration: App: DockingApp; ViewModel: AVPlayerViewModel; Model: AppModel; View: AVPlayerView, ContentView, ImmersivePickerView, ImmersiveView.
• Protocols: no app-defined protocol in the reviewed source.
• Commands use verb-led methods: makePlayerViewController, play, reset, playerViewController, makeUIViewController, updateUIViewController.
• Files and folders use primary-type or responsibility names such as Views, Models, Rendering, Components, Systems, Packages, or feature names where those boundaries exist.

Architecture takeaways

• Treat DockingApp as the owner of executable or scene lifecycle, not automatically as the owner of every entity created later.
• Keep view/controller input near presentation, but move sessions, reconstruction, capture, rendering, shared game state, or documents into stable owners when their lifetime exceeds one callback or render pass.
• Count authored Reality Composer Pro assets as implementation; the Swift shell is not the complete architecture.
• The compact source does not justify repository, coordinator, or protocol layers beyond boundaries the sample actually declares.

Source map

• Official Apple documentation