ReaperOfVeriod 05d9bf6cd7 The 72 concentrated candidates, and a float-constant ambiguity
Looking at the 72 candidates with fewer than 16 distinct immediates, the sets are
full of values that look like lui high halves: 0x3f80 is the high half of 1.0f,
and 0xff40/0xff70/0xff80/0xffc0 are negative high halves. 0xc0 << 16 is 0x00c00000,
a small float.

So 0xc0 in these functions may be a float constant rather than a chunk offset.
The neighbour control cannot tell the difference, because 0xb8 and 0xc8 are
equally plausible float high halves and are rare for their own reasons.

Also recorded, and explicitly not as a finding: exactly 1 of 394 candidates
contains another chunk offset, and none of the 72 does. That sounds like evidence
of moby-specificity and is not -- the other chunk offsets are 0x1e80 and above and
are globally rare (0 to 2 functions each, measured in 3ea5ab7), so their absence
here is exactly what rarity predicts.

What survives is the enrichment fact from a2f8c92. What does not survive is
reading 0xc0 as a chunk offset. There are now two live explanations, a moby chunk
reference and a float constant, and only disassembly separates them.

Cheapest test: 0x3a8060, 148 bytes, six immediates. If the lui carrying 0xc0 is
paired with an ori it is a float; if it feeds an addiu computing base + 0xc0 it is
the chunk.

284 passing with the disc present, clippy clean.
2026-10-14 05:36:13 +02:00
2026-10-11 20:59:19 +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.

PCSX2 is installed and working on this machine; the comparison loop that reads the game's own memory over its debug protocol is up, and level 0's and level 1's tfrag lighting are verified byte-exact against it. See docs/plan/pcsx2-verification.md for the setup and how to run it.

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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