ReaperOfVeriod 4bf552dab0 The alpha bug had a test named after the bug
Fixes a broken build left by 777a6a8, and the test it breaks is the interesting
part.

    texture::tests::alpha_is_scaled_from_eight_bit_halves
        assert_eq!(scale_alpha(0x7f), 0xfe);

That is not a test that happened to pin the wrong value. The test's NAME asserts
the wrong rule -- "scaled from eight bit halves" is the `a * 2` implementation
written down as intent, with 0xFE as its proof. Someone looked at this, thought
"alpha is a half-scale byte, double it", and then locked the conclusion into both
the identifier and the assertion.

So the previous commit's claim that `a * 2` was an implementation detail was wrong
in a way that matters: it had a name, a doc comment and a test defending it. That
is not an accident that escaped review, it is a convention that was adopted.

Two things follow.

The rule is now /128 * 255, and the test says so in its name. It also pins 0x7E ->
0xFB, a value the doubling cannot produce and which the disc does contain.

And 777a6a8 was pushed with a failing test in it. I only caught it because the
count came back as 100 rather than 278 and the discrepancy was worth one more
command -- `cargo test -q` plus a grep for `^test result: ok` sums only the
binaries that passed, so a failure is invisible in the total unless you go and
look at the raw lines. I had been using that filtered sum to report "278 tests"
for several commits without knowing it could hide a red build.

That is worth more than the bug it found. The measurement I had been reporting as
evidence of health was itself an instance of the defect this whole stretch has been
about: a quantity that should have had one definition, expressed as a filtered sum,
agreeing with the wrong answer and nobody comparing it against anything.

278 passing with the disc present, clippy clean.
2026-10-14 04:41:19 +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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