# Contributing — clean-room rules

This tree must stay publishable as engine code only. Never commit:
- game data in any form: `.gob` contents, extracted catalogs, saves, textures, strings dumps;
- the original binaries, or anything derived from them by a decompiler/disassembler
  (no decompiler output, no disassembly excerpts, no pasted pseudo-code — not even in comments);
- copied fixture files from the game. Test fixtures are hand-written minimal samples.

Facts *about* the binary (addresses, calling conventions, prototypes, struct layouts) enter this
repo only through `include/generated/sots_addresses.h`, which is generated from the RE repo with a
provenance header. Everything else is written from understanding, in our own words and code.

Real-data tests read `$SOTS_DATA_DIR` (the owner's installed copy) and must skip cleanly when unset.
Run `tools/clean_room_check.sh` before committing.

## Build toolchain gotcha

The engine needs **CMake >= 3.25**. Debian/Ubuntu hosts ship 3.22, which fails with an
unhelpful preset error. Either build on CT111 (which has 3.31), or locally:

```sh
uv run --with cmake --with ninja cmake --preset host -DPython3_EXECUTABLE=/usr/bin/python3
```

Pass `-DPython3_EXECUTABLE=/usr/bin/python3` explicitly — without it the fixture step
captures uv's ephemeral interpreter, which disappears after the run.

Two lanes independently hit the CMake floor, so to be explicit: if you do not want to build on
CT111, `uv tool install cmake` puts a current CMake on `~/.local/bin` and works for the host preset.