This guide takes a three.js feature from an open issue to a ticked box in the README. Every step has a check that make check enforces.

Every feature in the README checklist has an issue. Comment on the open issue you take. Open a new issue for a feature that is not listed.

Put a three.js port in the package that matches three.js: geometries/, helpers/, lights/, materials/, cameras/, core/, math/ or render/. Keep three.js names where Mojo allows them. Put original content under extensions/, in a folder per subject.

Follow the house rules:

• Give every quantity a unit type. A length is a Length, an angle is an Angle.
• Make every id, mode and kind a type with an is_valid method. Refuse a wrong value at the boundary that reads it.
• Write a docstring with Args, Returns and Raises on every public symbol.
• Keep the CPU and GPU rasterizers in step. Shared arithmetic lives in a module that both can import, such as render/fillrule.mojo.

Create or extend tests/test_<module>.mojo. Cover every line, every branch and every condition. Add:

• A test that constructs a wrong value inside the right type, and asserts the refusal.
• A file in tests/compile_fail/ for each new type that replaces a bare integer.
• A parity test in tests/test_gpu.mojo when the change touches shading or sampling.

make check
make coverage

Both must pass. make coverage lists what a test has not reached.

1. Add or update the reference page in docs/wiki/. Describe what the feature is and how to call it.
2. Add an explanation page when the design has a reason that is not obvious.
3. Run make docs-check.

Follow How to write documentation.

Tick the box in the feature checklist. Link it to the wiki page. Keep the issue number.

Write the commit message as a statement. Reference the issue with Closes #N. Run make check one more time before you push.