ReaperOfVeriod b66e77855c Locate a per-cell offset table in collision, on level 4
Range measured: longest strictly-ascending u32 run (delta under 65536) in each
level's collision payload, levels 0 to 5.

Level 4 is the clean case. Grid 3x25, payload 2660608, and at payload +5932 a
run of 19 entries whose values are all inside the payload, starting at 146012:

  deltas 204, 212, 216, 224, 224, 228, 228

The deltas grow monotonically, which is the signature of a prefix sum over
records of increasing size -- what a per-cell offset table looks like when cell
contents vary.

The others are not:

  level 0  11x33   +21232   17   8193, 24575, 8192, 8192   multiples of 8192,
                                                              coincidental on
                                                              dense data
  level 1  24x16   +41452   29   32771, 57339, 24575        wild, no trend
  level 2   1x53   +13752   49   24, 64, 396, 104          in-region but
                                                              irregular
  level 3  19x31  +667152   18   769, 257, 257, 257        values ~5.2e8, far
                                                              outside the payload
  level 4   3x25    +5932   19   204, 212, 216, 224        growing, in-region

Only level 4's run has both properties a prefix sum needs: values inside the
payload, and deltas that grow.

What this does not give: level 4's run is 19 entries against 75 grid cells, so
it is not one offset per cell -- either most cells share an offset, are empty,
or the table covers something other than the grid. Nothing measured picks between
those.

Next to check: whether 19 relates to 3x25 by any arithmetic, and whether the
same offset at +5932 exists in other levels at a position given by their leading
counts. Neither has been tried.
2026-10-12 03:03:18 +02:00
2026-10-11 20:59:19 +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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