ReaperOfVeriod
0b660cb0ce
Pulling the 0x80 convention out of the renderer and into gc_formats::gs -- the
side benefit I claimed last commit rather than took -- immediately produced a
contradiction, which is the argument for having done it.
crates/gc-engine/src/level.rs already read it inline:
let a = if c.a < 0x80 { c.a as f32 / 128.0 } else { 1.0 };
My first alpha_to_8 scaled by 127 instead of 128, which made 0x7F fully opaque
where the renderer had it at 253/255. One of them was wrong and it was not the new
one: the disc convention is a 0..0x80 range with 0x80 as the top, so 0x7F is
127/128, not 127/127.
Corrected to match, and the doc now records why -- including that the renderer was
already right, so this is a correction to code I wrote two commits ago rather than
to anyone else's.
One genuine ambiguity remains and it is stated rather than papered over: 0x40 is
exactly the midpoint, and the renderer works in floats where it is exactly 0.5.
Widening to an integer has to round, and this rounds half away from zero giving
128. There is no way to check that against the disc -- it needs a frame, which is
the tfrag morph item's unblock condition -- so it is documented as a choice.
The engine's call site keeps its inline form and now says why: it wants a float,
and the rule has one live site. Converting it would have meant changing working
code for no benefit, which is the opposite of what extracting the rule was for.
Worth noting what actually happened here. Extracting a rule to remove a magic
constant found that two expressions of it disagreed. Neither was obviously wrong
from its own code -- mine looked cleaner, and was not. That is a better argument
for centralising a rule than any amount of saying so.
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.