Rendering a scene with deferred lighting in C++

At a glance

Project structure

Source bundle/
├── Application/
│   ├── main.m
│   ├── AAPLAppDelegate.h
│   ├── AAPLAppDelegate.m
│   ├── AAPLViewController.h
│   ├── AAPLViewController.mm
│   ├── WindowSceneDelegate.h
│   └── WindowSceneDelegate.m
└── Renderer/
    ├── AAPLViewAdapter.h
    ├── AAPLRenderer.cpp
    ├── AAPLBufferExaminationManager.h
    ├── AAPLMesh.h
    └── AAPLRenderer.h

Structure observations

• Architecturally prominent files are ranked from entry points and role-named declarations; resource-only paths are omitted.
• Primary languages: C++, C/Objective-C header, Metal, Objective-C, Objective-C++, Python.
• The verified tree contains 9 project/configuration file(s) and 35 source declaration(s).

Overall architecture

flowchart LR
    Bundle["Sample bundle"]
    V1["Application"]
    V2["metal-cpp"]
    Boundary["Metal / metal_stdlib APIs"]
    Bundle --> V1
    V1 --> Boundary
    Bundle --> V2
    V2 --> Boundary

Reference code

Application/main.m:19 — architecture anchor

#if defined(TARGET_IOS) || defined(TARGET_TVOS)
int main(int argc, char * argv[])
{
    @autoreleasepool {
        return UIApplicationMain(argc, argv, nil, NSStringFromClass([AAPLAppDelegate class]));
    }
}
#endif

Interpretation

The branches represent separate entry-bearing project variants in the downloaded bundle, not runtime calls between those variants. Each branch is intentionally collapsed at the documented framework boundary; the detailed target-local flow remains in the cited files. Ownership is claimed only where the next section cites a stored property or assignment.

Ownership and state

classDiagram
    WindowSceneDelegate o-- UIWindow : window

Ownership evidence

Application/WindowSceneDelegate.h:17 — stored dependency or nearest verified ownership anchor

#if defined(TARGET_IOS) || defined(TARGET_TVOS)
@property (nonatomic, strong) UIWindow *window;
#endif

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.

No source-visible execution, scheduling, or synchronization boundary was found in the indexed source.

@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.

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/AAPLAppDelegate.h:12 — representative type boundary

#if defined(TARGET_IOS) || defined(TARGET_TVOS)
@interface AAPLAppDelegate : UIResponder <UIApplicationDelegate>

@end
#endif

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

Access control

Reference code

Application/WindowSceneDelegate.h:17 — representative boundary

#if defined(TARGET_IOS) || defined(TARGET_TVOS)
@property (nonatomic, strong) UIWindow *window;
#endif

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: Adapter: AAPLViewAdapter; Controller: AAPLViewController; Delegate: AAPLAppDelegate, WindowSceneDelegate; Manager: BufferExaminationManager; Renderer: Renderer.
• Protocols: no local protocol declaration in the scanned source.
• Methods: application, applicationShouldTerminateAfterLastWindowClosed, viewDidLoad, _setupView, dealloc, mtkView, drawInMTKView, touchesBegan.
• Files: Application/AAPLAppDelegate.h, Renderer/AAPLViewAdapter.h, Application/AAPLAppDelegate.m, Application/AAPLViewController.h, Application/AAPLViewController.mm, Application/WindowSceneDelegate.h.

Architecture takeaways

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