ReaperOfVeriod
31f4ba3f7c
Finishes the rule layer. Two traps, both of which produce a picture that looks slightly wrong rather than obviously broken: AFAIL READS BACKWARDS. The PS2's alpha-test register holds an enable, a 7-bit reference, and a bit that looks like "fail if alpha is above the reference". On the hardware it means the opposite -- AFAIL = 0 discards where alpha is BELOW the reference. passes_alpha_test takes the side explicitly rather than encoding the register, and both directions are tested so the convention is pinned in code rather than in a comment. THE OPAQUE BIT MUST STAY OUT OF THE COMPARISON. 0x80 is fully opaque, but it is also numerically 128, so a test that compares the raw byte against a 0x40 reference would have every fully-opaque fragment pass every threshold, and nothing would ever be discarded. passes_alpha_test clamps the opaque bit off first, and there is a test that asserts exactly that -- the failure mode here is a scene that renders correctly with the wrong shading, which is not something anyone notices by looking. Blend is the four GS primitive types, decoded from the primitive-type byte and named by what they do rather than by the documentation's IIIB/IIIA/IIIC labels, which name two different modes identically. Out-of-range types decode to Off rather than panicking, because the byte comes from asset data. Addition clamps at 255 rather than rescaling, matching the GS's 7-bit clamp; a caller wanting a true average blends before widening, and the doc says so. That completes the four rules the roadmap names for this item: alpha 0x80 == 1.0 alpha_to_8 CLAMP wrap clamp01 mip selection mip_level blend + alpha test BlendMode, passes_alpha_test Nine unit tests, no wgpu work, and the roadmap item stays [~] rather than [x] -- the rules are the input to the renderer, not the renderer. Worth noting the pattern in both traps: each one produces output that is plausible and slightly-off, with no error anywhere. That is the same shape as the sign inversion in mip_level and the byte-order bug in the anchor search. The tests are the only thing that catches this class, which is the argument for having them even though nothing here needs a GPU.
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.