Displaying a point cloud using scene depth
At a glance
| Item | Summary |
|---|---|
| Purpose | Present a visualization of the physical environment by placing points based a scene’s depth data. |
| App architecture | A Metal, Swift sample with the source-visible chain PointCloudDepthSample → MetalDepthView → MTKCoordinator → ARProvider → ARKit APIs. |
| Main patterns | Protocol-oriented abstraction, Delegate or data-source callbacks, Coordinator, Binding-based state propagation |
| Project style | 10 scanned source file(s) across Metal, Swift, organized around ranked entry, type, and file boundaries. |
Project structure
Source bundle/
├── pointCloudSample/
│ ├── PointCloudDepthSample.swift
│ ├── ARDataProvider.swift
│ ├── ARReceiver.swift
│ ├── MetalPointCloud.swift
│ ├── MetalViewSample.swift
│ ├── MetalTextureViewCoefs.swift
│ ├── MetalTextureViewConfidence.swift
│ ├── MetalTextureViewDepth.swift
│ ├── EnvironmentVariables.swift
│ └── shaders.metal
├── Configuration/
│ └── SampleCode.xcconfig
└── pointCloudSample.xcodeproj/
└── .xcodesamplecode.plist
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 4 project/configuration file(s) and 18 source declaration(s).
Overall architecture
flowchart LR
N1["PointCloudDepthSample"]
N2["MetalDepthView"]
N3["MTKCoordinator"]
N4["ARProvider"]
N5["ARKit APIs"]
N1 --> N2
N2 --> N3
N3 --> N4
N4 --> N5
Reference code
pointCloudSample/PointCloudDepthSample.swift:9 — architecture anchor
@main
struct PointCloudDepthSample: App {
var body: some Scene {
WindowGroup {
MetalDepthView()
}
}
}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 ARKit.
Ownership and state
classDiagram
MetalTextureContent o-- MTLTexture : texture
ARProvider *-- Float : guidedFilterEpsilon
ARProvider *-- ARReceiver : arReceiver
ARProvider o-- ARData : lastArData
Ownership evidence
pointCloudSample/ARDataProvider.swift:17 — stored dependency or nearest verified ownership anchor
final class MetalTextureContent {
var texture: MTLTexture?
}| Owner | Object or state | Relationship | Mutation authority |
|---|---|---|---|
MetalTextureContent |
MTLTexture (texture) |
stores or receives | App/module collaborators |
ARProvider |
Float (guidedFilterEpsilon) |
owns value state | Initialized by the owner; the binding is immutable |
ARProvider |
ARReceiver (arReceiver) |
creates and retains | Initialized by the owner; the binding is immutable |
ARProvider |
ARData (lastArData) |
stores or receives | App/module collaborators |
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.
Class and protocol design
pointCloudSample/ARReceiver.swift:14 — representative type boundary
protocol ARDataReceiver: AnyObject {
func onNewARData(arData: ARData)
}| Type | Responsibility | Depends on or conforms to |
|---|---|---|
ARProvider |
Supplies a capability or framework resource | ARDataReceiver |
MetalDepthView |
User-interface presentation and input forwarding | View |
MTKCoordinator |
Cross-object flow or session coordination | NSObject, MTKViewDelegate |
ARDataReceiver |
Defines a capability or collaboration contract | AnyObject |
PointCloudDepthSample |
Represents a feature value or composable behavior | App |
MetalTextureContent |
Owns feature behavior and collaborator lifecycle | Concrete collaborators/imported frameworks |
ARData |
Represents feature data | Concrete collaborators/imported frameworks |
ARReceiver |
Owns feature behavior and collaborator lifecycle | NSObject, ARSessionDelegate |
CoordinatorPointCloud |
Owns feature behavior and collaborator lifecycle | MTKCoordinator |
CameraModes |
Defines a closed set of feature states or choices | Concrete collaborators/imported frameworks |
The source explicitly defines local protocol relationships: ARProvider → ARDataReceiver.
Access control
| Symbol | Access | Verified effect | Likely rationale |
|---|---|---|---|
isToUpsampleDepth (pointCloudSample/ARDataProvider.swift:76) |
public |
The symbol is visible to importing modules. | Inference: make the declaration available across a module or target boundary. |
isUseSmoothedDepthForUpsampling (pointCloudSample/ARDataProvider.swift:83) |
public |
The symbol is visible to importing modules. | Inference: make the declaration available across a module or target boundary. |
EnvironmentVariables (pointCloudSample/EnvironmentVariables.swift:19) |
private |
Use is restricted to the lexical declaration and same-file extensions allowed by Swift. | Inference: hide an implementation step that is not part of the collaboration surface. |
selectedConfidence (pointCloudSample/MetalViewSample.swift:57) |
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. |
Reference code
pointCloudSample/ARDataProvider.swift:76 — representative boundary
public var isToUpsampleDepth: Bool = false {
didSet {
processLastArData()
}
}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 |
|---|---|---|
| Cross-object flow or session coordination | MTKCoordinator |
The source’s Coordinator suffix makes this role explicit. |
| Supplies a capability or framework resource | ARProvider |
The source’s Provider suffix makes this role explicit. |
| User-interface presentation and input forwarding | MetalDepthView |
The source’s View suffix makes this role explicit. |
Design patterns
| Pattern | Source evidence | Purpose or tradeoff |
|---|---|---|
| Protocol-oriented abstraction | pointCloudSample/ARDataProvider.swift:41 |
A local protocol and concrete conformance create an explicit capability boundary. |
| Delegate or data-source callbacks | pointCloudSample/ARReceiver.swift:30 |
Callback protocols invert event delivery back into the sample’s owner. |
| Coordinator | pointCloudSample/MetalTextureViewCoefs.swift:14 |
A role-named coordinator centralizes cross-object flow. |
| Binding-based state propagation | pointCloudSample/MetalPointCloud.swift:26 |
A binding exposes controlled read/write access while the upstream owner remains authoritative. |
Naming conventions
- Types: Coordinator: MTKCoordinator; Provider: ARProvider; View: MetalDepthView.
- Protocols:
ARDataReceiver. - Methods:
texture,createTexture,start,pause,onNewARData,processLastArData,session,makePerspectiveMatrixProjection. - Files:
pointCloudSample/PointCloudDepthSample.swift,pointCloudSample/ARReceiver.swift,pointCloudSample/MetalPointCloud.swift,pointCloudSample/MetalTextureViewCoefs.swift,pointCloudSample/MetalTextureViewConfidence.swift,pointCloudSample/MetalTextureViewDepth.swift.
Architecture takeaways
PointCloudDepthSampleis the main source-visible entry or composition anchor for this sample.- Framework work reaches SwiftUI, Metal, MetalKit, ARKit 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
| Source file | Relevant symbols |
|---|---|
pointCloudSample/PointCloudDepthSample.swift |
PointCloudDepthSample |
pointCloudSample/ARDataProvider.swift |
MetalTextureContent, ARProvider |
pointCloudSample/ARReceiver.swift |
ARDataReceiver, ARData, ARReceiver |
pointCloudSample/MetalPointCloud.swift |
CoordinatorPointCloud, CameraModes, MetalPointCloud |
pointCloudSample/MetalViewSample.swift |
Texture, MetalDepthView, MtkView_Previews |
pointCloudSample/MetalTextureViewCoefs.swift |
MTKCoordinator, MetalTextureViewCoefs |
pointCloudSample/MetalTextureViewConfidence.swift |
CoordinatorConfidence, MetalTextureViewConfidence |
pointCloudSample/MetalTextureViewDepth.swift |
CoordinatorDepth, MetalTextureViewDepth |
pointCloudSample/EnvironmentVariables.swift |
EnvironmentVariables |
pointCloudSample/shaders.metal |
Feature implementation |