Files

T

ReaperOfVeriod 16c04db559 Fix level extents read as bytes, and extract the level geometry

A defect in the Phase 1 extractor, found by reading the data extent's contents:
level extents are declared in sector counts, the generic G/ pair table uses byte
counts, and level containers were being routed through the generic path. So
LEVEL0.WAD's data extent -- 6,484 sectors -- was taken as 6,484 bytes. Every
test still passed, because a truncated file is still a file.

The extent's own header gave it away: it declares an uncompressed total of
13,277,920 bytes, and 13,277,920 / 6,484 is 2047.7. A ratio landing on 2048 is
a unit error, not a compression ratio. Across 27 levels this had been discarding
roughly 300 MB of level content.

Level containers now go through the typed LevelHeader instead. Level 0 yields:

  data.bin         13,279,232   the data extent
  core_data.wad     9,738,678   the geometry, compressed
  core_data.bin    16,969,296   the geometry, decompressed
  core_index.bin       31,600   the geometry directory
  gameplay.bin       659,456
  sound_bank.bin   1,503,232

core_data is a WAD LZ77 stream -- the format already implemented for the game --
and it decompresses cleanly. The first real level content this project has
recovered.

New: LevelDataHeader parses the data extent's own header, a table of byte ranges
naming the level overlay executable, the geometry directory, the GS RAM image,
the HUD banks and the geometry. Note this is a third meaning for a "size" field
on the same disc, after sector counts in the level header and byte counts in the
generic table; all three are documented together in level-data.md so the next
parser does not rediscover this the hard way.

The geometry directory's offsets were checked against the geometry rather than
taken on trust: all twelve land inside the 16.9 MB of decompressed core_data,
which is what confirms the header is being read correctly. The class tables
themselves do not yet decode under the documented layout, and that is recorded
as open work in plan/level-assets.md rather than papered over.

75 unit tests, 9 integration tests against the real disc. Hash table regenerated
at 5,159 files and 5,671,915,799 bytes -- hashes only, no content. Extraction
now writes to ~/Documents/gc-extracted rather than /tmp, which is 16 GB and did
not have room for a 5.3 GB output.

2026-10-09 16:28:26 +02:00

9.7 KiB

Raw Blame History

Roadmap

Status as of 2026-10-09.

A from-scratch native Rust reimplementation of Ratchet & Clank: Going Commando (PS2). Each phase ends in a gate — something checkable, not a feeling that it is going well. Phases are ordered so that the riskiest unknowns are retired early, while they are still cheap to retire.

Where we are

Target disc identified and verified (SCUS_972.68 v1.01, NTSC 60 Hz)
Workspace builds (cargo check --workspace)
Repository hygiene in place (pre-commit guard, .gitignore, licence record)
Phase 1 complete. The disc pipeline runs end to end and is verified against a committed hash table: 5,135 files, 4,500,106,960 bytes, every one of the 92 asset containers parsing.
Phase 2 in progress. Level containers are parsed through their typed header, and the data extent is parsed as a container of byte ranges. The geometry decompresses: level 0 yields 16,969,296 bytes of level content from a 9.7 MB stream.
Next: the geometry directory's class tables, then tfrag terrain.

The disc being the exact build the reference projects pin is the single biggest favourable fact so far: no disc conversion, no regional timing work, and no re-derivation of the reference baseline.

Phase 0 — Foundation ✅

Done.

Disc identified: SCUS_972.68 v1.01, USA Black Label, NTSC 60 Hz. Boot ELF SHA-1 bacda860cbd6723142e86db56f197e47e728970f, entry 0x00131AE8 — the entry point independently matches the value recorded by rac2-gc-decomp, which cross-confirms the identification.
tools/identify-disc.py reproduces the identification against any disc image and distinguishes a truncated dump from a non-PS2 image.
Five-crate workspace scaffolding, Bevy 0.19.1 pinned, builds clean.
.githooks/pre-commit blocks game data. Verified against seven cases: .iso, renamed disc image, WAD container, ADX container, extracted/, a 60 MiB file, and legitimate source.
AGENTS.md and PROVENANCE.md record conventions and licences.

Open from this phase

alsa-lib-devel is not installed, so Bevy's host audio backend is disabled in Cargo.toml. Audio is the last phase; revisit then.
Bevy feature set is deliberately minimal. Re-add features as needed rather than switching default-features back on wholesale.

Phase 1 — Disc pipeline ✅

Done. Gate met: every extracted file matches the committed hash table.

iso9660 reader (R&C2 lists assets as real files, unlike R&C1)
G/*.WAD container header parsing — 92 containers, three table shapes
WAD LZ77 decompression (wad.rs, four packet classes)
Unpack every container, bounds-checking each extent
SHA-1 table for all 5,135 files (hashes only, never content)
verify stage, plus integration tests against a real disc
Format specs written: disc-layout.md, global-wad.md, wad.md
Work record with the negative results: plan/disc-pipeline.md

gc-extract identify disc.iso        -> SCUS_972.68 v1.01 NTSC, ELF SHA-1 matches
gc-extract unpack   disc.iso out/   -> 5135 files, 4,500,106,960 bytes, 10.8s
gc-extract verify   out/ table.tsv -> OK: 5135 files match

Not done, deliberately: the table of contents at sector 1001 is documented but not read. Enumerating the ISO filesystem is simpler and sufficient; the ToC matters when per-level overlay loading is understood in Phase 3.

Two wrong turns are recorded in plan/disc-pipeline.md, because both would be easy to repeat: the container pair table read backwards, and the LZ77 stream mistaken for a bit stream. Both produced plausible-looking wrong output before failing, which is the failure mode worth guarding against.

Phase 2 — Format parsers

Goal: every asset type parses into plain Rust values, tested against real disc data.

Phase 1 hands over the extents; this phase works out what each one contains.

Done so far:

level_wad.rs — the 0x60-byte header on all 27 level containers, naming four extents plus three chunk descriptors. Verified: extents tile each container in file order (27 of 27).
Two facts the format documentation does not state, both measured here: sizes in this header are sector counts where the generic G/ table uses byte counts, and LEVEL21.WAD reports level id 30, so container order is not level identity.

In progress:

data — the extent header locates core_index and core_data; the geometry decompresses and is verified on level 0.
core_index class tables — offsets all land inside core_data, which confirms the header, but the ArrayRange fields do not decode to a usable class table under the documented layout. Next thing to resolve.
gameplay — begins WAD + a per-level byte, and does not decode with the WAD LZ77 decoder. All 27 levels fail identically, so the input is wrong rather than the decoder. Ruled out: bit order, header length, the LZ77 framing. Hypotheses queued in plan/level-assets.md.
occlusion — 2 to 25 sectors, small enough to read whole.
sound_bank — SBlk and DAW signatures found in all 27.
data — the large one: 4.2 to 21.9 MB of geometry per level.
tfrag — terrain: LOD chains, strips, morph targets
tie — instanced environment geometry, fat vertices
shrub — foliage and decorative meshes
moby — dynamic actors; moby_anim — skeletal animation
collision — cells, packed vertices, faces
occlusion — the PVS grid
sky, volumes, textures (CSM1 CLUT + PS2 alpha)
level_overlay — the seven-section parser and relocation from Phase 3

Gate: every parser has a golden test against bytes from the real disc, and reports mismatched header counts as failures rather than warnings.

Discipline: bound every read. Typed errors, no panics, no reads past the buffer.

Phase 3 — Overlay system

Goal: make 27 level overlays tractable.

Every overlay carries the same seven sections (.lit, .bss, .data, lvl.vtbl, lvl.camvtbl, lvl.sndvtbl, .text) and the same engine code, linked at different addresses. ReRAC solves this by masking relocations — j/ jal targets, lui immediates of main-RAM addresses, the %lo that completes them, and $gp-relative operands — then matching the masked words to find a reference function's copy on another overlay.

Port the masking and code-identity logic
Relocation::func and Relocation::data
$gp for this game (0x001AEFF0, against R&C1's 0x166c00)
Extend the level table from 19 to 27

Gate: every level-01 function's relocated copy is found on all 27 overlays; cross-checked against an independent cluster hash.

Why this is high-value: it turns "27 overlays of unknown code" into a table lookup, and it is the main thing inherited from ReRAC.

Phase 4 — Engine core

Goal: draw a frame.

Graphics Synthesizer in wgpu, with the GS's own rules: its round(log2(z/n) + K) mip selection, blend and alpha-test behaviour, alpha 0x80 meaning 1.0, CLAMP wrap
VU0/VU1 skinning and lighting on the PS2 float model
LOD/morph/cull per TfragProc and TieProc
Occlusion culling, fog, shadows
GIF/VIF packet stream interpretation

Gate: CPU and GPU paths agree on every vertex of a reference level — the same identity check ReRAC runs.

Risk: VU1 microcode is binary in the game's .vutext section, so it is reverse engineered rather than parsed. This is the hardest single item in the project and the main threat to the timeline. Note that ReRAC's own moby VU1 analysis trips their disassembler on two opcodes.

Phase 5 — Veldin vertical slice

Goal: one planet, playable start to finish.

Ratchet's controller on a spherical planet
Chargeboots: hold/release timing, chained jumps, dash
Wrench and the camera
Collision and the HUD

Gate: Veldin is completable and visually matches PCSX2 frame-for-frame under replayed input.

This is the go/no-go for the project. If Veldin works, the other 26 levels are content. If it does not, the reason is discovered while it is still cheap. Spherical gravity is the thing most likely to break, because it invalidates R&C1's movement and camera assumptions wholesale.

Phase 6 — Remaining overlays and the shell

Per-level moby class dispatch via lvl.vtbl
Remaining 26 levels
Planets, travel, the Gadgetron vendor, RPG upgrades
Weapon modification bitmasks (lock-on, shock, acid, …)
Minigames and challenges
The 25-state memory-card FSM and its UI
IFF chunk saves, including import of a R&C1 save to unlock legacy weapons

Phase 7 — Audio and video

989snd v2 audio decode and playback (not CRI ADX — a different codec)
SPU2 mixing, reverb zones, level sounds
IPU/MPEG-2 video for the title screen and cutscenes

Phase 8 — Fidelity pass

Differential testing against PCSX2 across every level:

Recorded-input frame comparison, per planet
Geometry, fog, blend, alpha, texture sampling
Audio sync and 60 Hz timing
Behavioural comparison: traversal routes, boss timing, RNG

Principles

A gate is pass/fail, not a percentage. "Looks fine" is not progress.
Negative results are written down. A ruled-out approach saves the next attempt as much as a working one.
The float model is not negotiable. Approximate is not the same as faithful, and the difference is visible in how the game feels.
Fidelity over tidiness. Where the original does something that looks like a bug, reproduce it and say why in a comment. See AGENTS.md.

9.7 KiB Raw Blame History