ReaperOfVeriod
cee17c95b1
Closes the ambiguity 05d9bf6 raised. At 0x3a8060:
263200c0 addiu r17, r18, 0x00c0 r17 = r18 + 0xc0
263000d0 addiu r17, r16, 0x00d0 r17 = r16 + 0xd0
262400e0 addiu r17, r4, 0x00e0 r17 = r4 + 0xe0
3c013f80 lui r0, r1, 0x3f80 the actual float constant: 1.0f
0xc0 is an address offset, not a float constant. The float constant is in the same
function and is 0x3f80, where it belongs -- so the ambiguity does not arise here,
and the reading of 0xc0 as moby_classes.offset survives.
The three offsets are 0xc0, 0xd0, 0xe0: sixteen bytes apart. The function walks a
table of fixed-stride structures and indexes the field at offset 0xc0, which is
what a class-table lookup looks like.
WHAT THIS DOES NOT SETTLE
That 0x3a8060 is the moby class loader. It indexes a 16-byte-stride table at
offset 0xc0, which is consistent with a moby class walk, with a different
structure that also lives at 0xc0, and with ordinary field access on an object
handed in by the caller.
The entry code sets a 64-byte frame and saves r16 through r20, and the three
indexes come off three different registers -- r18, r16 and r4. So the walk is over
arguments, not over a global. That is informative in itself: a loader would more
plausibly be handed the chunk by its caller than re-derive core_data + 0xc0 on
every call. Which also means the chunk reference is in the *caller*, and that is
where the next step is.
NEXT STEP, narrow and concrete: trace where r18 and r4 come from, and find the
call sites of this function. If a caller does `addiu r, base, 0xc0` and passes it
in, that caller is doing the chunk lookup and this function is the per-class work
inside it.
Worth recording how long the ambiguity took to close. It was raised one commit ago
and resolved by reading twelve instructions. Five commits before that the same
constant was reported as a "real shortlist", and two before that as a size
artifact. Every one of those states was arithmetically correct; only this one was
the right question, and it took looking at the operands rather than counting them
to arrive at it.
284 passing with the disc present (23 + 19 + 64 + 156 + 22; disc binary 35.00s),
clippy clean.
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.