ReaperOfVeriod
1f903efe23
OpenRAC/rac2-gc-decomp is the same disc as ours, verified rather than assumed:
ours 3,828,350,976 9db2e33e...b1ce5
theirs 3,828,350,976 9db2e33e...b1ce5
Vendored read-only under vendor/ (already gitignored) and added to PROVENANCE.
It names two constants this parser had measured but never explained:
* overlay.bin +0x00 = 1,735,808 = 0x1A7C80, the .lit load base. It is constant
across all 27 levels because every level's literal section loads at the same
address. So the first header word is the load base of the section the file IS,
which also establishes that overlay.bin is that section -- it holds both code
and the debug string pool. $gp = 0x1AEFF0 comes with it, and that closes the
roadmap's open "$gp for this game" item.
The program around it is seven sections -- .lit .bss .data vtbl camvtbl sndvtbl
.text -- which is precisely the "seven-section parser and relocation" Phase 3
item for this format. Known target now rather than a guess.
I then tested the obvious follow-up and it is wrong: if +0x00 is the .lit load
base, +0x0c ought to be the .lit size. It is SMALLER than the file on 16 of 27
levels, by up to 8.9% (level11: file 3,151,128 vs 2,870,792). Excluded by sign,
not by a near miss. Still unnamed.
Collision: still blocked, but no longer blocked on tooling. The decomp names
Camera_CollPrimTest(void *prim, void *grid) without decompiling it, so the cell
layout is not handed over. What it does supply is $gp, and that is enough to
start. "Camera_CollPrimTest WARNING! - grid out of bounds! (RAR)" is at
overlay+0xd18, the only copy in the file, so:
string overlay+0xd18 -> RAM 0x1a8998; delta to $gp -0x6658; $lo 0x99a8
MIPS puts the $lo half in bytes 1..3 of a 4-byte instruction. Searching the whole
overlay instruction-aligned gives exactly ONE hit:
0x354cc8 (overlay+0x1ad048)
One occurrence in 2.75 MB of code is unambiguous: that is the instruction
materialising the assert string, and its enclosing function is
Camera_CollPrimTest. That is the route in, and it needs no symbols.
tools/overlay-anchors does this step, dependency-free. I started this with
capstone for the disassembly proper and dropped it: capstone 0.14 does not
re-export Mode/Endian from a public path, and an excluded-from-the-workspace
native dependency is a poor trade for a step that does not need one yet. The
anchor search is pure byte work, so it is pure Rust. No native dependency is
added anywhere, and the tool is an ordinary workspace member.
Surveyed the rest of that project against our open items: no volume structures,
no tie vertex layouts, no SBlk/DAW fields, no wavelet tables. It is a guide to
the code, not a replacement for reading it.
5.9 KiB
PROVENANCE
This project is built on the work of other people. Their licences apply to their code, and those notices travel with anything derived from it.
Summary
| Project | Role | Licence | Code copied into this repo? |
|---|---|---|---|
| OpenRAC/rac2-gc-decomp | Byte-exact reconstruction research for the same disc (SHA-256 verified identical) -- supplied $gp, the .lit load base and the seven-section program layout |
GPL-3.0-or-later | Not yet; vendored read-only at vendor/rac2-gc-decomp |
| ReRAC | Native Rust/Bevy port of Ratchet & Clank (2002) — the architecture this follows | ISC | Not yet; derived from, attribute when used |
| OpenRAC / rac2-gc-decomp | Matching decompilation research for this game | MIT | No — consulted for documentation |
| rac2-gc-decomp community reference | Engine architecture notes, moby struct layout | MIT | Documentation only |
| Wrench | Insomniac container format documentation | GPLv3 | No. Specification reference only |
| RAC2Decomp | Functional decompilation, PAL | MIT | Not used — see below |
Game content: none
No game assets, disc images, extracted data, BIOS dumps or proprietary
toolchains are or may be committed to this repository. The build takes the
user's own legally obtained disc as input. This is enforced by
.githooks/pre-commit.
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.
ReRAC — ISC
The direct model for this project. ReRAC re-implements the first Ratchet & Clank as a native Rust application on Bevy, reading assets from the player's own disc. This project follows the same architecture for the second game.
What we take from ReRAC:
- The architecture. Crate split (
formats/extract/game/engine/video), Bevy 0.19.1, the PS2 float-model discipline, and the milestone gating style. - Overlay relocation.
rc-formats::level_overlayimplements relocation-tolerant code-identity matching so one level's function can be found on every other level. R&C2's 27 overlays have the same seven-section layout (.lit,.bss,.data,lvl.vtbl,lvl.camvtbl,lvl.sndvtbl,.text), so this machinery transfers directly. It is the single most valuable thing we inherit. - Verified format specs.
docs/formats/disc_layout.mddocuments all four R&C games' container layouts, derived from behavioural analysis. - Discipline worth copying. Golden tests against committed snapshot hashes; bit-exact CPU/GPU identity checks; documenting negative results.
ISC permits use, modification and redistribution with the notice intact. When code is derived from ReRAC it must carry:
Copyright (c) 2026 ReRAC contributors
Licensed under the ISC License.
Pinned checkout: vendor/rerac at commit
d00cb00ad4018f776556e72640dcba438d098a77 (2026-10-09). Not tracked by git —
clone it yourself; the commit is recorded so everyone uses the same one.
Note that ReRAC targets a different game. Its per-level documentation is a useful hint about Insomniac's engine in general, but R&C2's spherical worlds changed roughly 50,000 lines of gameplay code, so nothing about R&C1's movement, camera or level geometry should be treated as directly applicable.
OpenRAC / rac2-gc-decomp — MIT
Matching decompilation research for this game, targeting exactly our disc
(SCUS_972.68 v1.01). It reconstructs the boot ELF and all 27 level overlays
byte-for-byte, and publishes verified struct layouts, symbol names and engine
documentation.
We use it as a reference, not as source. Its value is that it tells us what the structures are, which saves a great deal of guessing.
Its matching progress is low (~1.6% of code in C) and byte-matching is not a prerequisite for this port anyway — it is a verification technique. We are not pursuing a byte-identical rebuild.
Wrench — GPLv3, specification reference only
Community documentation and tooling for Insomniac's container formats. We use the written format specifications as a reference for how the data is laid out.
No Wrench code is copied into this repository. That is deliberate and
load-bearing: copying GPLv3 code would impose GPLv3 terms on everything derived
from it. Clean-room reimplementation from a written specification does not. If
this boundary is ever crossed, the licensing of this project changes and
AGENTS.md must be updated to say so.
RAC2Decomp — not used
A functional (non-byte-matching) decompilation of the PAL release. It is recorded here only so its absence is a decision rather than an oversight.
The rac2-gc-decomp community reference explicitly flags it as "criticized by
community for questionable provenance and non-clean-room C code. Avoid
copying." Given that we are building a reimplementation and its provenance is
disputed, we do not use it. It is also the wrong region: PAL, 50 Hz.
Third-party libraries
Rust dependencies keep their own licences; see Cargo.lock and each crate's
LICENSE file. Notable ones:
- Bevy (MIT / Apache-2.0) — application framework and wgpu renderer.
- wgpu / wgpu-hal / wgpu-types (MIT / Apache-2.0) — GPU abstraction used for the Graphics Synthesizer reimplementation.
- bytemuck (Zlib OR Apache-2.0 OR MIT) — zero-copy casts over asset structures.
- thiserror, anyhow (MIT OR Apache-2.0) — error handling.
When you add a dependency or port code
- Record it in this file, with its licence and what you took.
- Keep the upstream notice intact in any file containing derived code.
- If it would change this project's licensing terms, stop and say so first.