Applying temporal antialiasing and upscaling using MetalFX

At a glance

Project structure

Source bundle/
├── Application/
│   ├── iOS/
│   │   ├── AAPLAppDelegate.swift
│   │   ├── AAPLViewController.swift
│   │   └── Base.lproj/
│   │       ├── LaunchScreen.storyboard
│   │       └── Main.storyboard
│   └── macOS/
│       ├── AAPLAppDelegate.swift
│       └── AAPLViewController.swift
└── Renderer/
    ├── AAPLRenderer.swift
    ├── AAPLRenderTarget.swift
    ├── AAPLRendererHelper.swift
    ├── Shaders.metal
    ├── AAPLMathUtilities.swift
    └── ShaderTypes.h

Structure observations

• Architecturally prominent files are ranked from entry points and role-named declarations; resource-only paths are omitted.
• Primary languages: C/Objective-C header, Metal, Swift.
• The verified tree contains 8 project/configuration file(s) and 9 source declaration(s).

Overall architecture

flowchart LR
    N1["AAPLAppDelegate"]
    N2["AAPLViewController"]
    N3["AAPLRenderer"]
    N4["Metal APIs"]
    N1 --> N2
    N2 --> N3
    N3 --> N4

Reference code

Application/iOS/AAPLAppDelegate.swift:10 — architecture anchor

@main
class AAPLAppDelegate: UIResponder, UIApplicationDelegate {
    // ...
    var window: UIWindow?
    // ...
}

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 MetalFX.

Ownership and state

classDiagram
    AAPLAppDelegate o-- UIWindow : window
    AAPLRenderer *-- Bool : animationEnabled
    AAPLRenderer *-- Bool : resetHistoryEnabled
    AAPLRenderer *-- Bool : firstFrameTemporal

Ownership evidence

Application/iOS/AAPLAppDelegate.swift:13 — stored dependency or nearest verified ownership anchor

@main
class AAPLAppDelegate: UIResponder, UIApplicationDelegate {
    // ...
    var window: UIWindow?
    // ...
}

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

Renderer/AAPLRenderer.swift:43 — representative execution boundary

class AAPLRenderer: NSObject, MTKViewDelegate {
    // ...
    let inFlightSemaphore = DispatchSemaphore(value: AAPLMaxBuffersInFlight)
    // ...
}

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

Application/iOS/AAPLAppDelegate.swift:11 — representative type boundary

@main
class AAPLAppDelegate: UIResponder, UIApplicationDelegate {
    // ...
    var window: UIWindow?
    // ...
}

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

Access control

Reference code

Renderer/AAPLRenderTarget.swift:22 — representative boundary

class AAPLRenderTarget {
    // ...
    public var renderScale: Float = 0.5
    // ...
}

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: Controller: AAPLViewController; Delegate: AAPLAppDelegate; Renderer: AAPLRenderer.
• Protocols: no local protocol declaration in the scanned source.
• Methods: application, applicationWillResignActive, applicationDidEnterBackground, applicationWillEnterForeground, applicationDidBecomeActive, applicationDidFinishLaunching, applicationWillTerminate, applicationShouldTerminateAfterLastWindowClosed.
• Files: Application/iOS/AAPLAppDelegate.swift, Application/macOS/AAPLAppDelegate.swift, Renderer/AAPLRenderer.swift, Application/iOS/AAPLViewController.swift, Application/macOS/AAPLViewController.swift, Renderer/AAPLRenderTarget.swift.

Architecture takeaways

• AAPLAppDelegate is the main source-visible entry or composition anchor for this sample.
• Framework work reaches MetalKit, simd, Cocoa, Metal 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