ReaperOfVeriod aec462df21 Record that shrub span bounds are wrong, and what that invalidates
A follow-up measurement contradicted the body size implied by the
differential analysis, and the cause is bad span bounds rather than
anything in the format.

Shrub spans were bounded by the next shrub offset, with the last running
to the end of core_data. On level 0 that gives the final shrub class a
925,008-byte span, absorbing most of the lump's tail. The moby-to-tie
boundary is clean by comparison: last moby offset 13414592, first tie
13416192, exactly 1600 bytes apart.

What that invalidates:

- The 3.5M record / 28 MB body figure is an artifact of the oversized final
  span and should not be quoted.
- The "payload looks uniform-random" measurement ran over the same
  contaminated range, so it says nothing about shrub geometry either way.
- The differential result itself still stands -- it was computed on groups,
  and the groups used had bounded spans. The global aggregates built on it
  do not.

What is needed is the offset ending the shrub region. It is not in the core
index, and there is no obvious successor boundary the way moby->tie has one.

This is the second confident-sounding number in this format that turned out
to rest on a bad bound, the first being the VIF reading. Aggregates across
many spans are only as good as the span bounds under them, and bounds are
the easy thing to get wrong because nothing errors when you do.
2026-10-11 02:54:19 +02:00

Going Commando

A native PC reimplementation of Ratchet & Clank: Going Commando (PlayStation 2, 2003), written in Rust.

The game is reimplemented, not emulated. There is no MIPS interpreter here and no CPU emulator: the systems are ported to Rust so they run as ordinary native code.

Status: initial scaffold. The disc is identified and verified, the workspace builds, and nothing else is implemented yet. See docs/roadmap.md for where things stand and what comes next.

The target

Game Ratchet & Clank: Going Commando
Platform PlayStation 2
Disc SCUS_972.68 v1.01, USA Black Label
Video NTSC, 60 Hz
Boot ELF SHA-1 bacda860cbd6723142e86db56f197e47e728970f

Verified against a real disc — see docs/disc-identification.md. This is the build the reference projects pin; Greatest Hits v2.00 is a different binary and is not the target.

No game content

This repository contains no game assets, no disc images, no BIOS dumps and no proprietary toolchains. You supply your own legally obtained copy of the disc as an input, the way the upstream reference projects do.

A pre-commit hook enforces this, blocking disc images, asset directories, container signatures and files over 50 MiB. If you clone elsewhere, enable it:

git config core.hooksPath .githooks

Layout

crates/
  gc-formats/    asset format parsers (pure, no I/O beyond the caller's buffer)
  gc-extract/    disc pipeline: identify, unpack, verify
  gc-game/       game logic: hero, weapons, moby classes, progression, saves
  gc-video/      IPU / MPEG-2 decode
  gc-engine/     Bevy app: Graphics Synthesizer, VU0/VU1, renderer, frame loop
docs/
  disc-identification.md   which disc we build against, verified
  roadmap.md               phases, gates, current status
  plan/                    one file per subsystem, written as work proceeds
  formats/                 format specs, written as formats are reversed
tools/
  identify-disc.py         identify any Going Commando disc image
vendor/
  rerac/                   pinned upstream reference checkout (not tracked)

Building

Requires a Rust toolchain via rustup.

cargo check --workspace
cargo test  --workspace

The host audio backend is disabled in Cargo.toml (see the comment there) so that the workspace builds without system ALSA development headers. Audio decode is the last phase of the port and lives in gc-video; re-enable it and install alsa-lib-devel when that work starts.

Identifying a disc

python3 tools/identify-disc.py <your-disc.iso>

Reports the serial, version and video mode from SYSTEM.CNF, hashes the boot executable, and warns when the disc is not the supported build. Reads only a few megabytes, so it is near-instant.

How it will be verified

Visual and behavioural comparison against PCSX2, replaying recorded input and comparing frames, level by level. The PS2 float model is reproduced rather than approximated — see AGENTS.md.

Credits and licensing

This project learns from and is built on the work of others. Licences are recorded in PROVENANCE.md and notices must travel with any code derived from them.

  • ReRAC — a native Rust/Bevy port of Ratchet & Clank (2002), the first game. ISC. The architecture this project follows.
  • OpenRAC / rac2-gc-decomp — matching decompilation research for this game. MIT. Source of verified struct layouts and engine documentation.
  • Wrench — community documentation of Insomniac's container formats. GPL, used as a specification reference only; no code is copied.

Ratchet & Clank is a trademark of Sony Interactive Entertainment. This is an unofficial fan project, not affiliated with or endorsed by Sony Interactive Entertainment or Insomniac Games.

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