Code audit: find duplicated / orphan / unused code in WebARKit (excluding vendored lib/SRC and AR/ headers)

[kalwalt]

Goal

Sweep the WebARKit-specific C++ code for duplicated, orphan, or unused code, and clean it up. Several recent fixes (#43, #44, #46) surfaced vestigial paths (e.g. the disabled pyrDown block, the no-op _featureDetectScaleFactor rescale) that had been carrying dead weight for a long time. Likely there is more.

Scope

In scope — WebARKit/ only:

• WebARKit/WebARKitTrackers/WebARKitOpticalTracking/WebARKitTracker.cpp + headers
• WebARKit/WebARKitTrackers/WebARKitOpticalTracking/TrackingPointSelector.{h,cpp}
• WebARKit/WebARKitTrackers/WebARKitOpticalTracking/HomographyInfo.{h,cpp}
• WebARKit/WebARKitTrackers/WebARKitOpticalTracking/WebARKitConfig.{h,cpp}
• WebARKit/WebARKitManager.{h,cpp}, WebARKit/WebARKitCamera.{h,cpp}, WebARKit/WebARKitGL.{h,cpp}, WebARKit/WebARKitPattern.{h,cpp}, WebARKit/WebARKitLog.{h,cpp}

Out of scope — vendored code:

• lib/SRC/AR/**, lib/SRC/ARUtil/**, include/AR/** (vendored old ARToolKit5 sources/headers — untouched).
• OpenCV and submodules under opencv/, opencv_contrib/.

Note: ArtoolkitX remains the design reference for the OCVT planar tracker under WebARKit/WebARKitTrackers/WebARKitOpticalTracking/ (cross-checked against artoolkitx/artoolkitx); that is separate from the vendored ARToolKit5 utility code.

Companion scope — also audit webarkit/webarkit-testing

• src/ (JS controller + utils)
• emscripten/ glue (WebARKitJS.{h,cpp}, bindings.cpp)
• examples/ (post-Fix CV->GL pose conversion in updateTrackable() #36 cleanup) — small surface; spot-check for orphans
• tools/makem.js (any orphan source entries)
• Look for dead package.json scripts / webpack.config.js targets (already trimmed SpeedyVisionSinkImageData in webarkit-testing#41).

What to look for

• Dead members: fields declared on WebARKitTrackerImpl and friends that are written but never read (or never written).
• Commented-out blocks that have outlived their purpose (e.g. the pyrDown/detection-guard blocks were finally removed in Feature keypoints double-scaled for frames larger than featureImageMinSize (marker mis-localized at ~2x position) #43/Restore downsampled feature detection + single-marker detection guard for performance (reconcile with ArtoolkitX OCVT) #44 prep; check for others).
• _trackVizActive / TrackerVisualization — referenced throughout but no public toggle / not consumed by any example. Confirm dead-or-load-bearing.
• getPoseMatrix vs getPoseMatrix2 — both are bound to JS but only getPoseMatrix2() is read in process_raw(). Is the other unused?
• computePose in WebARKitPattern.cpp — declared but not called from anywhere in the live path.
• getTransformationMatrix vs getGLViewMatrix vs matrixGL_RH — three GL-ish matrices flowing through the manager + bindings; some may be unused by every consumer.
• points2d / points3d on _pattern — populated in initTracker but check for use.
• Duplicated helpers (e.g. convert2Grayscale, GrayScale JS class, and convertJSArrayToNumberVector paths).
• process_raw vs processFrame — both shapes exist; one wraps the other; check if both are still consumed.
• Header-only declarations whose .cpp definitions are gone, and vice-versa.

Acceptance

• Per-file inventory of dead / duplicated / orphan code, with proposed removal.
• Each removal verified to leave behavior unchanged (recompile + the static-image and webcam examples track).
• If any "dead-looking" symbol turns out to be load-bearing (used by another consumer / tooling), document why and leave it.
• Repeat the inventory + cleanup pass on the in-scope parts of webarkit-testing.

Tooling

• clang-tidy (misc-unused-using-decls, bugprone-*, readability-*)
• compiler warnings with -Wunused-* + -Wmissing-declarations
• cppcheck for dead-code detection
• ripgrep / xref for "declared but never called" sweeps

Notes

This is a quality / debt issue, not a bug — defer behind active bug work (#44 perf, #48 markerless).

[kalwalt]

Inventory complete (doc only — removals to follow)

Manual cross-repo (C++ + JS/bindings) dead-code inventory done, audited at submodule 28ff065. Doc + master cleanup decision table: docs/audit-dead-code-issue50.md in webarkit/webarkit-testing#44. No code removed yet — each removal gets its own verified PR (recompile + static + webcam examples track).

Named suspects — resolved

• getPoseMatrix vs getPoseMatrix2 → both kept as public API, but getPoseMatrix is broken (returns a zero pose3d) → filed as getPoseMatrix() returns a zero matrix — pose3d is never populated in the live path #55, with rename getPoseMatrixCV/getPoseMatrixGL riding along.
• computePose → dead (only commented call); drags in invertPose, computeGLviewMatrix() no-arg, pose3d, and the _pattern.points2d/points3d it consumed.
• getTransformationMatrix/getGLViewMatrix/matrixGL_RH → keep (public API); emitted in getMarker even if examples render only matrixGL_RH.
• _trackVizActive/TrackerVisualization → unreachable (no setter exists) → DECIDE: wire a toggle or remove.
• process_raw vs processFrame → not a duplicate (public entry vs internal helper) — keep both.
• _pattern.points2d/points3d → dead (orphaned inputs of computePose); keep the struct (size is live, Fix crash when a marker is detected on the first frame (#37) #38).
• grayscale/convert2Grayscale/GrayScale.js → distinct layers, all live.

Additional confirmed-dead (per-file in the doc)

getWebARKitVersion, getTracker, update() (declared, never defined), the cv::Mat initTracker/arglCameraViewRHf overloads, getDistortionCoefficients, GetAllFeatures/CleanUp, WebARKitHomographyInfo::inlier_matches, TrackedPoint::IsSelected/markerRoi, grayscale()/im_gray()/webarkitGetVersion(char**), and dead constants N / featureDetectPyramidLevel / VERSION_MAJOR/MINOR/TINY/DEV.

Clean

Examples (full HTML→worker graph traced), tools/makem.js, webpack.config.js, WebARKitEnums.h — no orphans.

Coverage

Full xref on Manager, Pattern, GL, Camera, Config, TrackingPointSelector, HomographyInfo, TrackedPoint, Utils, Enums + the JS/glue/examples chain + the active paths of WebARKitTracker.cpp (commented _trackables[...] scaffolding characterised, ~37 lines). Low-risk remaining: WebARKitLog, individual package.json scripts.