ml

C++ computer-vision playground — Bazel 9 + Bzlmod + OpenCV 5.

ml/
├── app/            # binaries
│   └── ml          # camera preview
├── camera/         # capture + display
└── libs/
    └── opencv/     # system OpenCV → Bazel cc_library

Requirements

Tool	Notes
Bazel	7+ (via Bazelisk)
OpenCV	4/5 — brew install opencv
macOS	Camera permission for Terminal / IDE

Optional override if OpenCV is non-standard:

export OPENCV_PREFIX="$(brew --prefix opencv)"

Quick start

# build
bazel build //app:ml

# run preview (default device 0)
bazel run //app:ml

# another device index
bazel run //app:ml -- 1

Press q or Esc to quit.

If capture fails with “not authorized”, open
System Settings → Privacy & Security → Camera and allow your terminal.

Layout

Target	Role
//app:ml	Entry binary
//camera	Thin OpenCV capture loop
//libs/opencv	Alias to @opencv (system install)
@opencv	Auto-discovered via pkg-config / Homebrew

OpenCV is not built from source. A local repository rule finds headers and dylibs and exposes them as a normal cc_library — fast, hermetic enough for local work, and tracks OpenCV 5 from Homebrew.

Tooling

• C++20 (--cxxopt=-std=c++20 in .bazelrc)
• clang-format style in .clang-format
• MODULE.bazel only — no WORKSPACE