Simulating particles in your visionOS app

At a glance

Project structure

Source bundle/
├── Particle Emitter/
│   ├── ParticleEmitterApp.swift
│   ├── EmitterView.swift
│   ├── MainView.swift
│   └── EmitterSettings.swift
├── Packages/
│   └── RealityGestures/
│       ├── Sources/
│       │   └── RealityGestures/
│       │       ├── RealityDragComponent.swift
│       │       ├── GeneralGoalComponent.swift
│       │       ├── RealityTapComponent.swift
│       │       ├── SwiftUI+RealityGestures.swift
│       │       └── RealityDragComponent+DragEvents.swift
│       └── Package.swift
├── EmitterControls.swift
└── LabelSlider.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 5 project/configuration file(s) and 19 source declaration(s).

Overall architecture

flowchart LR
    N1["ParticleEmitterApp"]
    N2["MainView"]
    N3["GeneralGoalSystem"]
    N4["RealityKit APIs"]
    N1 --> N2
    N2 --> N3
    N3 --> N4

Reference code

Particle Emitter/ParticleEmitterApp.swift:10 — architecture anchor

@main
struct ParticleEmitterApp: App {
    /// Stores settings for the particle emitter.
    @ObservedObject public var emitterSettings = EmitterSettings()

    var body: some Scene {
        WindowGroup {
            MainView()
        }.environment(emitterSettings)
    }
}

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
    ParticleEmitterApp o-- EmitterSettings : emitterSettings
    RealityDragComponent o-- Rotationlocked : rotationLocked
    RealityDragComponent o-- Clamp : clamp
    RealityDragComponent o-- Dragupdate : dragUpdate

Ownership evidence

Particle Emitter/ParticleEmitterApp.swift:13 — stored dependency or nearest verified ownership anchor

@main
struct ParticleEmitterApp: App {
    // ...
    @ObservedObject public var emitterSettings = EmitterSettings()
    // ...
}

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

Packages/RealityGestures/Sources/RealityGestures/RealityDragComponent.swift:24 — representative execution boundary

    public init(
        // ...
    ) {
        // ...
    }

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

Particle Emitter/ParticleEmitterApp.swift:11 — representative type boundary

@main
struct ParticleEmitterApp: App {
    // ...
    @ObservedObject public var emitterSettings = EmitterSettings()
    // ...
}

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

Access control

Reference code

EmitterControls.swift:23 — representative boundary

    public var body: some View {
        // ...
                presetSection
        // ...
    }

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: ParticleEmitterApp; Component: GeneralGoalComponent, RealityDragComponent, RealityTapComponent; System: GeneralGoalSystem; View: EmitterView, MainView.
• Protocols: no local protocol declaration in the scanned source.
• Methods: getCollisionPoints, getClampedPosition, getClampedRotation, handleMoveState, handleRotationState, closestPoint, clamp, get.
• Files: Particle Emitter/ParticleEmitterApp.swift, Packages/RealityGestures/Sources/RealityGestures/RealityDragComponent.swift, Packages/RealityGestures/Sources/RealityGestures/GeneralGoalComponent.swift, Packages/RealityGestures/Sources/RealityGestures/RealityTapComponent.swift, Particle Emitter/EmitterView.swift, Particle Emitter/MainView.swift.

Architecture takeaways

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