Capturing depth using the LiDAR camera

At a glance

Project structure

Source bundle/
└── LiDARDepth/
    ├── LiDARDepthApp.swift
    ├── ContentView.swift
    ├── Model/
    │   ├── CameraController.swift
    │   └── CameraManager.swift
    └── Views/
        ├── Metal/
        │   ├── MetalContentView.swift
        │   ├── MetalTextureView.swift
        │   ├── MetalPointCloud.swift
        │   ├── MetalTextureColorThresholdDepth.swift
        │   ├── MetalTextureColorZap.swift
        │   ├── MetalTextureViewColor.swift
        │   └── MetalTextureViewDepth.swift
        └── DepthOverlay.swift

Structure observations

• Architecturally prominent files are ranked from entry points and role-named declarations; resource-only paths are omitted.
• Primary languages: Metal, Swift.
• The verified tree contains 3 project/configuration file(s) and 26 source declaration(s).

Overall architecture

flowchart LR
    N1["LiDARDepthApp"]
    N2["ContentView"]
    N3["MTKColorTextureCoordinator"]
    N4["AVFoundation APIs"]
    N1 --> N2
    N2 --> N3
    N3 --> N4

Reference code

LiDARDepth/LiDARDepthApp.swift:10 — architecture anchor

@main
struct LiDARDepthApp: App {
    var body: some Scene {
        WindowGroup {
            ContentView()
        }
    }
}

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 AVFoundation.

Ownership and state

classDiagram
    ContentView *-- CameraManager : manager
    ContentView *-- Float : maxDepth
    ContentView *-- Float : minDepth
    ContentView *-- Float : scaleMovement

Ownership evidence

LiDARDepth/ContentView.swift:14 — stored dependency or nearest verified ownership anchor

struct ContentView: View {
    // ...
    @StateObject private var manager = CameraManager()
    // ...
}

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

LiDARDepth/Model/CameraController.swift:26 — representative execution boundary

class CameraController: NSObject, ObservableObject {
    // ...
    private let videoQueue = DispatchQueue(label: "com.example.apple-samplecode.VideoQueue", qos: .userInteractive)
    // ...
}

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

LiDARDepth/Model/CameraController.swift:12 — representative type boundary

protocol CaptureDataReceiver: AnyObject {
    func onNewData(capturedData: CameraCapturedData)
    func onNewPhotoData(capturedData: CameraCapturedData)
}

The source explicitly defines local protocol relationships: CameraManager → CaptureDataReceiver, MetalPointCloudView → MetalRepresentable, MetalTextureColorThresholdDepthView → MetalRepresentable, MetalTextureColorZapView → MetalRepresentable, MetalTextureView → MetalRepresentable, MetalTextureViewColor → MetalRepresentable.

Access control

Reference code

LiDARDepth/ContentView.swift:14 — representative boundary

struct ContentView: View {
    // ...
    @StateObject private var manager = CameraManager()
    // ...
}

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

Main application flow

sequenceDiagram
    participant Session as Capture session
    participant Sync as Data synchronizer
    participant Controller as CameraController
    participant Manager as CameraManager
    participant View as Metal views
    Session->>Sync: video + depth outputs
    Sync->>Controller: synchronized collection
    Controller->>Controller: create textures and CameraCapturedData
    Controller->>Manager: onNewData(capturedData)
    Manager->>Manager: update stable capturedData reference
    Manager-->>View: published dataAvailable/state
    View->>View: coordinators render textures

Reference code

LiDARDepth/Model/CameraController.swift:159 — dataOutputSynchronizer

    func dataOutputSynchronizer(_ synchronizer: AVCaptureDataOutputSynchronizer,
                                didOutput synchronizedDataCollection: AVCaptureSynchronizedDataCollection) {
        // Retrieve the synchronized depth and sample buffer container objects.
        guard let syncedDepthData = synchronizedDataCollection.synchronizedData(for: depthDataOutput) as? AVCaptureSynchronizedDepthData,
              let syncedVideoData = synchronizedDataCollection.synchronizedData(for: videoDataOutput) as? AVCaptureSynchronizedSampleBufferData else { return }

        guard let pixelBuffer = syncedVideoData.sampleBuffer.imageBuffer,
              let cameraCalibrationData = syncedDepthData.depthData.cameraCalibrationData else { return }

        // Package the captured data.
        let data = CameraCapturedData(depth: syncedDepthData.depthData.depthDataMap.texture(withFormat: .r16Float, planeIndex: 0, addToCache: textureCache),
                                      colorY: pixelBuffer.texture(withFormat: .r8Unorm, planeIndex: 0, addToCache: textureCache),
                                      colorCbCr: pixelBuffer.texture(withFormat: .rg8Unorm, planeIndex: 1, addToCache: textureCache),
                                      cameraIntrinsics: cameraCalibrationData.intrinsicMatrix,
                                      cameraReferenceDimensions: cameraCalibrationData.intrinsicMatrixReferenceDimensions)

        delegate?.onNewData(capturedData: data)
    }

Naming conventions

• Types: App: LiDARDepthApp; Controller: CameraController; Coordinator: MTKColorTextureCoordinator, MTKColorThresholdDepthTextureCoordinator, MTKColorZapCoordinator, MTKCoordinator, MTKDepthTextureCoordinator; Manager: CameraManager; View: ContentView, MetalPointCloudView, MetalTextureColorThresholdDepthView, MetalTextureColorZapView, MetalTextureDepthView.
• Protocols: CaptureDataReceiver, MetalRepresentable.
• Methods: onNewData, onNewPhotoData, setupSession, setupCaptureInput, setupCaptureOutputs, startStream, stopStream, dataOutputSynchronizer.
• Files: LiDARDepth/LiDARDepthApp.swift, LiDARDepth/ContentView.swift, LiDARDepth/Model/CameraController.swift, LiDARDepth/Model/CameraManager.swift, LiDARDepth/Views/Metal/MetalTextureView.swift, LiDARDepth/Views/Metal/MetalTextureViewColor.swift.

Architecture takeaways

• LiDARDepthApp is the main source-visible entry or composition anchor for this sample.
• Framework work reaches SwiftUI, Metal, MetalKit, AVFoundation 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.
• Local protocol relationships provide an explicit substitution boundary.

Source map

• Official Apple documentation