ReaperOfVeriod
4abce518e5
Range measured: all 27 levels' overlays. The overlay carries the game's profiler menu definition -- a run of 8-byte padded names (normal, camera, cam+chr, volume, bars, render, mobys, ties, shrubs, cpu/gpu, occl, ...) followed by runs of absolute RAM addresses that point back at those same names. On every level the four addresses after normal/camera/cam+chr/volume, each minus its target name's overlay offset, give the same number: 1,735,792. That is field_00 - 16, where field_00 is the header word that read 1,735,808 on all 27 levels with nothing attached to it. The overlay is loaded with its 16-byte header stripped, so overlay offset X sits at RAM X + 1,735,792. OverlayHeader::ram_address carries it, and the disc test asserts the derivation holds on all 27 levels. Confirmed, not only derived: level 0's RAM 0x1acf80 holds "normal\0camera\0cam+chr\0volume\0", byte-identical to overlay 0x5310, and 0x5310 + 1735792 == 0x1acf80. All four names land where the overlay's own table says. `gc-trace verify-overlay-base` runs that check, savestate-gated the same way as the tie and tfrag ones. The overlay is relocated, not copied: only 37.67% of level 0's is byte-identical at the base, and the 256-entry sine table -- at overlay 0xb650c -- is not at 0xb650c + base. So the base locates the overlay's image, but individual tables inside it move. That is the shape of a loader applying relocations, and it means the base is necessary but not sufficient for reading the game's tables. The value of the base is that any overlay offset can now be carried to a RAM address, which is the prerequisite for reading the game's live level state -- the thing the tie relocation and tfrag lighting checks had to work around. Two things get deleted rather than finished. The collision u16 table was probed four ways -- magnitude distribution, level-independence, run starts, run lengths -- and every one came back level-dependent: the run-start pattern is identical on 1 of 19 levels. So the first 1024 bytes of the collision payload are data, not a fixed table, and nothing was decoded. Recorded as the negative it is rather than left as four half-findings.
639 lines
39 KiB
Markdown
639 lines
39 KiB
Markdown
# Roadmap
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Status as of **2026-10-11**.
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A from-scratch native Rust reimplementation of Ratchet & Clank: Going Commando
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(PS2). Each phase ends in a **gate** — something checkable, not a feeling that
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it is going well. Phases are ordered so that the riskiest unknowns are retired
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early, while they are still cheap to retire.
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## Where we are
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- [x] Target disc identified and verified (`SCUS_972.68` v1.01, NTSC 60 Hz)
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- [x] Workspace builds (`cargo check --workspace`)
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- [x] Repository hygiene in place (pre-commit guard, `.gitignore`, licence
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record)
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- [x] **Phase 1 complete.** The disc pipeline runs end to end and is verified
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against a committed hash table, every one of the 92 asset containers
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parsing. The pipeline now also writes each level's chunk descriptors
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where they exist (3 of 27 levels).
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- [x] **Phase 2 in progress.** Level containers are parsed through their typed
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header, and the `data` extent is parsed as a container of byte ranges. The
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geometry decompresses: level 0 yields 16,969,296 bytes of level content
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from a 9.7 MB stream.
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- [x] **Parsers with real-disc tests, per asset type.** `level_wad`, `data`,
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`core_index` class tables, `tfrag` (format, topology, textures, LOD,
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normals, colour), `occlusion`, `sky`, `moby`, `collision` framing and
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header, `shrub` (blob, packets, palette, billboard), the post-shrub
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`chunks` container, `sound_bank` framing and `level_overlay`. 238 tests
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green against the real disc. **What is open is naming, not locating** --
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see the Phase 2 list for the four types that still have no decoded
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fields: `tie` vertices, collision cells, `SBlk` records, `volumes` and
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`moby_anim`.
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- [x] **Lighting verified against the running game.** PCSX2 2.8.2 with savestates
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for level 0 and level 1. The tfrag lighting pass is byte-exact on both
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against the game's own RAM. Setup and method in
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`plan/pcsx2-verification.md`.
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- [x] **First drawable frame.** `gc-engine` loads a level, applies LOD selection
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and morphing for the camera, groups triangles by texture and draws them
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under a Bevy fly-camera. Level 0 renders as 26,758 textured triangles
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across 92 textures with correct UVs. Set `GC_ENGINE_SHOT=<path.ppm>` to
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capture a frame and exit.
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- [ ] **The origin bug this exposed.** Positions are i16 offsets from a
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per-patch origin, so taking the wrong STROW collapsed the whole level to
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a +-32 unit blob at the world origin while every parser test still
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passed: the vertex count matched, the triangle count matched, only the
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*place* was wrong. Fixed by taking the STROW immediately preceding the
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first position unpack rather than the last one.
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- [x] **Per-vertex colour.** The tfrag's RGBA array now modulates the texture,
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drawn unlit so the frame shows real albedo rather than a faked lighting
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model. Verified against the stored values (level 0 patch 0 runs
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`(25,26,26)` to `(108,144,141)`), which are genuinely dark.
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- [x] **Tfrag normals.** The 256-entry sine table is decoded from the level
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overlay and normals are built per vertex and handed to the renderer. The
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overlay has **no ELF header**, so the table cannot be reached through a
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program header, and its offset differs per level (level 0 `0xb650c`,
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level 5 `0xcca30`); it is located by matching the whole 256-entry curve.
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Normals are negated as stored and get the same axis swap as positions.
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The pipeline now also writes `overlay.bin`.
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- [x] **The PS2 float model.** `gc-engine::ps2` is the EE's FPU on raw bits: no
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denormals, no NaN or infinity, truncation toward zero, the adder's
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operand alignment, and `rsqrt` as sqrt-then-divide. `MAX` reads back in
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Rust as NaN, which is the sharpest available statement of why this is
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not `f32`.
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- [x] **The `LightTfrags` pass** is written and unit-tested against the PS2
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model: PEXT5 base colour, `select` set blending, re-normalised blended
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directions, and `base + A*max(dA, dA*wA) + B*max(dB, dB*wB)`.
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- [x] **The level light bank parses and level 0 is fully lit.** `gameplay` is a
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WAD stream; the extractor had been writing it compressed, which is why
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the bank framing found garbage. All 80,274 vertices of level 0 now go
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through `LightTfrags`. The renderer still counts and reports how many
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vertices it lit, because a silent fallback to stored colours would look
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plausible and be wrong.
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- [x] **The shrub region is bounded, and with it the whole lump.** Shrub's end
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was the last unlocated region bound: it is the start of the post-class
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chunk container, found by a marker-paired signature in `core_data` (the
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index carries no successor offset). The container closes shrub on the
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24 shrub levels and tie on the three without. All 358 shrub class bodies
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are now bounded and are whole 8-byte records, so shrub measurements are
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trustworthy for the first time -- the "3.5M records" figure from the
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unbounded final span is replaced by a measured 9,600.
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- [x] **Lighting *magnitudes* are verified** by the PCSX2 comparison loop.
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`gc-trace compare-tfrag-light` runs the pass over level 0's disc data and
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diffs it against the game's own lit colours in EE RAM (live over PINE, or
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from a savestate): **all 162,400 colour bytes match**, across 833/833
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headers relocated and the light bank byte-identical. Two bugs it found:
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the normal's z was not negated (dark but plausible, 95.88% agreement),
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and records with no light set drew transparent black instead of the base
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colour. See `docs/plan/pcsx2-verification.md`.
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- [ ] Then the GS register set and the guard-band clip test.
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The disc being the exact build the reference projects pin is the single
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biggest favourable fact so far: no disc conversion, no regional timing work,
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and no re-derivation of the reference baseline.
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---
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## Phase 0 — Foundation ✅
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**Done.**
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- Disc identified: `SCUS_972.68` v1.01, USA Black Label, NTSC 60 Hz. Boot ELF
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SHA-1 `bacda860cbd6723142e86db56f197e47e728970f`, entry `0x00131AE8` — the
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entry point independently matches the value recorded by `rac2-gc-decomp`,
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which cross-confirms the identification.
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- `tools/identify-disc.py` reproduces the identification against any disc image
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and distinguishes a truncated dump from a non-PS2 image.
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- Five-crate workspace scaffolding, Bevy 0.19.1 pinned, builds clean.
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- `.githooks/pre-commit` blocks game data. Verified against seven cases:
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`.iso`, renamed disc image, WAD container, ADX container, `extracted/`,
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a 60 MiB file, and legitimate source.
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- `AGENTS.md` and `PROVENANCE.md` record conventions and licences.
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### Open from this phase
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- `alsa-lib-devel` is not installed, so Bevy's host audio backend is disabled in
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`Cargo.toml`. Audio is the last phase; revisit then.
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- Bevy feature set is deliberately minimal. Re-add features as needed rather
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than switching `default-features` back on wholesale.
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---
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## Phase 1 — Disc pipeline ✅
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**Done.** Gate met: every extracted file matches the committed hash table.
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- [x] `iso9660` reader (R&C2 lists assets as real files, unlike R&C1)
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- [x] `G/*.WAD` container header parsing — 92 containers, three table shapes
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- [x] WAD LZ77 decompression (`wad.rs`, four packet classes)
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- [x] Unpack every container, bounds-checking each extent
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- [x] SHA-1 table for all 5,135 files (hashes only, never content)
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- [x] `verify` stage, plus integration tests against a real disc
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- [x] Format specs written: `disc-layout.md`, `global-wad.md`, `wad.md`
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- [x] Work record with the negative results: `plan/disc-pipeline.md`
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```text
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gc-extract identify disc.iso -> SCUS_972.68 v1.01 NTSC, ELF SHA-1 matches
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gc-extract unpack disc.iso out/ -> 5135 files, 4,500,106,960 bytes, 10.8s
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gc-extract verify out/ table.tsv -> OK: 5135 files match
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```
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**Not done, deliberately:** the table of contents at sector 1001 is documented
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but not read. Enumerating the ISO filesystem is simpler and sufficient; the ToC
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matters when per-level overlay loading is understood in Phase 3.
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**Two wrong turns are recorded** in `plan/disc-pipeline.md`, because both would
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be easy to repeat: the container pair table read backwards, and the LZ77 stream
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mistaken for a bit stream. Both produced plausible-looking wrong output before
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failing, which is the failure mode worth guarding against.
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---
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## Phase 2 — Format parsers
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**Goal:** every asset type parses into plain Rust values, tested against real
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disc data.
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Phase 1 hands over the extents; this phase works out what each one contains.
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**Done so far:**
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- [x] `level_wad.rs` — the 0x60-byte header on all 27 level containers, naming
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four extents plus three chunk descriptors. Verified: extents tile each
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container in file order (27 of 27).
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- [x] Two facts the format documentation does not state, both measured here:
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sizes in this header are **sector counts** where the generic `G/` table
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uses byte counts, and **`LEVEL21.WAD` reports level id 30**, so container
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order is not level identity.
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**In progress:**
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- [x] `data` — the extent header locates `core_index` and `core_data`; the
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geometry decompresses and is verified on level 0.
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- [x] `core_index` class tables — moby, tie and shrub. They were ruled out
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for want of an entry size, which is knowable exactly: each table ends
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precisely where the next begins, and that chain closes on 27 of 27
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levels. 32 bytes per moby/tie entry, 48 per shrub. Across the disc:
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**5,796 moby, 1,864 tie, 358 shrub classes**. Identifying `tfrag` by its
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own structure is what led here.
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- [x] `occlusion` and `sky` offsets located and their first bytes read.
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- [x] Region layout of `core_data` established: tfrag, occlusion, sky, collision
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and `textures_base` are offsets, strictly increasing on all 27 levels.
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Terrain is `[0, occlusion)` and carries inline texels.
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- [x] Region layout **closed**: the chunk container's marker-paired signature
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ends the last class region, and the constant trailer ends the container.
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Every byte of level-specific `core_data` now belongs to a named region.
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- [x] **tfrag vertex format: recovered.** The tfrags block header gives a table
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offset (`0x40`) and a patch count; each patch is a 0x40-byte header whose
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`data` offset is relative to the table, not to the block. Positions are
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V3_16 payloads inside a VIF1 command list, split across three lists per
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patch (common, LOD 0+1, LOD 0). The whole vector format is encoded in the
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command byte and every element size follows from it. Verified on all 27
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levels: **18,102 patches, 821,439 vertices**, each patch yielding exactly
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its own `vert_count`. See `plan/level-assets.md` and `gc-formats::tfrag`.
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- [x] **tfrag topology: recovered.** Vertex-info (UVs plus LOD parenting), the
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strip command lists and the index arrays, classified by unpack format and
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destination VU address. Strip indices address the vertex-info array
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rather than positions. Every patch's strips expand to exactly its own
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`tri_count`: **18,102 patches, 809,879 triangles**, all indices in range.
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See `plan/level-assets.md` and `gc-formats::tfrag`.
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- [x] **tfrag texture bindings and per-vertex data.** The ad-gifs decode to a
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texture index, wrap modes, minification filter and LOD bias; the level
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index gained a texture table (`level_core.rs`) for those indices to land
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in. Per-vertex RGBA and light/normal records recovered from their fixed
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offsets. All 27 levels: 47,950 ad-gifs, every index in range, 90% of the
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level texture tables referenced.
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- [x] **Level textures decode.** 8-bit indexed texels plus a 256-entry CSM1
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CLUT from `gs_ram`, honouring the PS2 CLUT block swap and the 0x80 alpha
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scale. The pipeline now writes `gs_ram.bin`, which it had been skipping.
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All 1,595 tfrag textures on all 27 levels decode; 96.8% fully opaque and
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96.3% with real detail. Verified visually via the new
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`gc-extract dump-texture`, because a wrong lookup still yields a
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well-formed image of the wrong thing.
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- [x] **tfrag LOD selection.** Switch distances scale as `[6L, 4L, 2L]` from the
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block header's float; six draw modes result from testing the bounding
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sphere against `trunc(D * 1024)`, so a patch straddling a threshold takes
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the coarser mode and distance never moves back to finer detail. Morph
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weights run 0..1 across each tier's band, and collapse replaces an entry
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with its first parent rather than blending it.
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- [x] **tfrag parent indices.** The four V4_8 arrays are classified by VU
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address, but the addresses collide, and each V4_8 element holds four
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indices so an array is `count * 4` bytes rather than `count`. With
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`unk_06`/`unk_0a` suppressing absent tiers, all 370,349 LOD entries
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across the 27 levels resolve: 29,043 LOD-01 and 341,306 LOD-0, zero
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failures. See `plan/level-assets.md` for the two corrections.
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- [x] `gameplay` — **it is a WAD stream**, exactly like `core_data`; the
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extractor was writing it compressed. Decompressed, level 0 is 1,872,256
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bytes and holds 5 directional light sets. The earlier "does not decode
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with the WAD LZ77 decoder, bit order and header length ruled out" note
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was wrong about the cause: the decoder was right and the input was not
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what it looked like. Corrected in `plan/level-assets.md`.
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- [~] `sound_bank` — the `SBlk` head is now characterised: `"SBlk", 1, 4,
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"DAW\0", 0` constant on 27/27, and `+0x14` is the only varying word, with
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its low 16 bits always zero (`0x0092..=0x0103`). It tracks body length at
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~100 bytes/unit and is **not** a count -- ratio 91.2..110.8, and no stride
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makes it exact. The absence of a stride is asserted too. Container framing parsed (`SoundBankHeader::parse`,
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`parse_sound_bank`); `SBlk` and `DAW` bounds verified on 27/27. The
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**record fields inside `SBlk` are not decoded**, and `DAW` shows no
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detectable stride, consistent with ADPCM. See the note under
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`level_overlay` below for what the game's own strings say about loading.
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- [x] `data` — **not geometry.** It is the level's file descriptor: its
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first table carries the exact byte lengths of `overlay.bin`,
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`core_index.bin` and `gs_ram.bin` at fixed `u32` indices 1, 3 and 5 on
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every level checked. What follows the descriptor is still unknown.
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- [x] `tfrag` — **complete on the disc side.** Vertex format, topology, strips
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(`TfragStrip`), texture bindings, per-vertex colour and normals, LOD
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selection, parent indices, morphing and collapse. 36 format tests, 9 texture
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tests, 23 engine tests. The morphing is a blend toward the **parent
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vertices'** midpoint, not toward separate morph targets — there are no
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morph targets in this format, which is what the old "morph targets
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unrecovered" note wrongly implied.
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- [x] The tfrag **table record has exactly two relocated pointer fields**, at
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`+0x10` and `+0x38`, verified against PCSX2 across all **833** records: the
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loader adds the **table's** RAM address (`0x848040` = block base plus
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`table_offset`, matching `TfragHeader::data`'s own "relative to the table")
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to `+0x10`; every other byte of every record is verbatim, and 1,665 fields
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differ where 1,666 were possible.
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They are the existing `TfragHeader::data` and `::cube_ofs` -- what RAM adds
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is that both are **pointers**, not plain offsets. All **833** patches parse,
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carrying **43,613** vertex-info entries; **499 of 833** have at least one
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morphing entry.
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- [x] Behind those pointers, **every patch's bytes are rewritten** -- and it is
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**not morphing**. Across all 833 patches: the 334 with **no** morphing
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entries differ by a median **7.80%**, the 499 with morphing entries by
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**8.12%**, and **0 of 833** are byte-identical to disc. Morphing does not
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predict which bytes change. Nor is it a relocation: the differences fall in
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short structured runs with no common `u32` addend. The loader regenerates
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each patch's **VU packet stream for the LOD tier it selected**, which
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happens to every patch regardless of morphing.
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- [ ] What tfrag is **not** yet verified is that the morph matches
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`resolve_vertex`'s formula. Reading a weight back out of RAM does **not**
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work -- the positions live inside regenerated VU packets, so there is no
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stable per-vertex correspondence. The LOD switch distances, morph weight and
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collapse edge remain derived from the data (tiers classified from the four
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V4_8 parent arrays, weight running zero to one across each band); verifying
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them needs the **camera distance at the savestate** so the weight can be
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computed and compared against the rendered result.
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- [x] The tie class header's **`+0x0c` word is the three LOD record
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counts** — LOD 0 at `+0x0c`, LOD 1 at `+0x0d`, LOD 2 at `+0x0e` — verified
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on **1,864 of 1,864** classes by reading the counts independently from
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the blocks' own record tables. This was filed as "R&C1's normals offset,
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read past, not decoded", which was the right action on the wrong map:
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R&C1 carries the same quadruple at `+0x20` and it is not an offset on
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R&C2. The fourth byte is unidentified and is *not* the shader total
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(disagrees on 1,827 of 1,864).
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- [x] `tie` — **fully chained.** `resolve_tie_class` walks both indirections: the
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class table is in `core_index.bin`, and the entry's `offset_in_asset_wad`
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addresses `core_data.bin` (not `core_data.wad`). All **1,864** tie classes
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resolve with `o_class` agreeing on every one. A `packets` word of **zero
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means no block at that LOD** -- 2,177 real blocks, 1,551 absent slots.
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- [x] Tie **blocks are self-delimiting**: `parse_tie_block` walks to the `0xf6`
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terminator that every real block carries (2,177 of 2,177), followed by zero
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padding. This is what makes blocks parseable at all -- `packets[1]` bounds
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one on only 461 of 1,864 classes.
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- [x] The tie **16-byte record is R&C1's `TiePacketHeader`.** Identified not by
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resemblance but by R&C1's own rule, `bfc_distance == 5 * shader_count`,
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holding on **15,219 of 15,219** records across all 2,177 blocks. A block is
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`[16-byte header][record table][vertex payload]`, and the header word at
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`+0x00` is the byte offset from the block start to the payload. The earlier
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"variable-length, not 16-byte records" reading was wrong: the word is not
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an element count, which is why dividing the payload by it gave 0 of 922.
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- [x] The tie **vertex element is 16 bytes**, measured over 95,612 vertices on
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levels 0-2 and settled by comparison: a 12-bit-fixed texcoord hit rate of
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**82.5%** at 16 bytes against 47.8% at 8 and 44.8% at 12.
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- [x] `i16[0..2]` are the **vertex positions**: LOD1/LOD2 of one class share 96.1%
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of their position triples, while LOD1 of A against LOD2 of B shares 0.4% --
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a factor of 240, asserted including the ratio. Axis order and scale unnamed.
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- [x] `i16[3]` is a **byte-sized index**, not a coordinate: 201 distinct values in
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`0..=254` inside the ordinary layout, whose high byte is the layout tag
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(93.4% of elements are `0x00`, 5.6% are `0x03`, 146 selector values in all).
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Asserted.
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- [x] The tie **texcoord field is located**: `i16[4]`/`i16[5]` of the 16-byte
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element, scoring 73.6% for 12-bit fixedness over 36,501 level-0 vertices,
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against 1.1% for `(0,1)` and 4.8% for `(2,3)`. The `(6,7)` pair scores
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*higher* at 76.6% and is **not** a texcoord -- it is the near-constant
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`4096, 0` pair, which is trivially two multiples of 4,096.
|
|
- [x] `i16[3]` **selects the texcoord encoding**, and it is specifically the
|
|
**high byte**. Grouped across 95,612 vertices on levels 0-2: high byte `0x00`
|
|
covers 89,341 vertices (93.4%) at 92% 12-bit fixed, while **every** other
|
|
high byte scores 0%. The split is on the byte, not the value -- `i16[3]` of 1
|
|
and of 771 differ only in the high byte and behave completely differently.
|
|
Within the all-zero case, `i16[3] == 0` exactly (5,851) is a third
|
|
distribution at 62%. Three cases: `0x00/0x00`, `0x00/1..255`, and non-zero
|
|
high byte.
|
|
- [~] The remaining tie vertex **fields are not named**, and two readings are now
|
|
excluded. `i16[6]`/`i16[7]` are constant across a whole draw packet in
|
|
43%/34% of records, so they are usually per-packet rather than per-vertex.
|
|
`i16[3]` is per-vertex (50 distinct values per packet) but **not a skin or
|
|
joint index**: vertices sharing it are 0.95x *farther* apart than vertices
|
|
differing in it, against a control that halves. It is also unshared across
|
|
LODs. Recorded as not understood rather than guessed.
|
|
`i16` range with 10,803-13,421 distinct values each. `i16[0..2]` are most
|
|
likely position, but that is not established.
|
|
- [~] `shrub` — class table done (48-byte entries, not 32; reading shrub at
|
|
32 still gives 231 sane-looking entries of 358, which is the hazard).
|
|
Geometry header parsed and checked field by field on all 358 spans:
|
|
`+0x24` equals the entry's own `o_class`, `+0x2c` is an in-span data
|
|
offset, `+0x16`/`+0x18` are zero, and `+0x1c` names a billboard on
|
|
exactly the 25 classes whose core-index entry carries billboard texture
|
|
fields. Shrub does **not** use moby's part-table format. The body is a
|
|
**24-entry palette of unit-length s16 normals** (squared length within
|
|
65,535 of 32767² on all 8,592 entries — a random triple would miss by a
|
|
billion) plus zero padding records; the billboard record carries K, MMIN
|
|
and the TEX0/MIPTBP addresses as R&C1's does. What remains open: the
|
|
three floats in the billboard record, `size`, `mode_bits`, `count`, and
|
|
**where the mesh geometry lives** — R&C1 puts the mesh packets in this
|
|
blob and R&C2's blob holds only the palette.
|
|
- [x] **The tie LOD block is a table of 16-byte records.** The header's word at
|
|
`+0x00` is the byte offset from the block start to the vertex payload --
|
|
the record table's length -- not a count, which is why the payload never
|
|
divides by it. Each record is a leading `u32` pointer **relative to the
|
|
table start** plus twelve verbatim field bytes, relocated at load to
|
|
`table + word`.
|
|
- [x] **The record is R&C1's `TiePacketHeader`.** R&C1's own rule
|
|
`bfc_distance == 5 * shader_count` holds on **all 15,219 records of all
|
|
2,177 blocks on all 27 levels**. R&C1's rule for the colour offset holds
|
|
on **none** of them, so the games use that field differently.
|
|
- [x] **The tie relocation verifies on two levels.** `gc-trace
|
|
verify-tie-records` checks it against PCSX2's RAM: **87 of 87** blocks on
|
|
level 0 and **104 of 104** on level 1, zero mismatches, which is what
|
|
makes the record layout a finding rather than a reading of one block.
|
|
- [x] **The shrub mesh geometry is in the class blob.** A packet table at
|
|
`+0x40` names `count` packets between the table and the palette, and
|
|
they tile on **358 of 358 spans** (2,239 packets), which makes `count`
|
|
the packet count. Confirmed against the running game, which relocates
|
|
the table's offsets to absolute addresses and `data_offset` likewise.
|
|
- [x] `moby` — per-class model geometry. A class span opens with a `u32`
|
|
pointing at a part table of 16-byte records; parts tile exactly, with
|
|
`vertex_offset + 16 * vertex_count == next_part` holding for **43,467 of
|
|
43,467** parts across every class on all 27 levels. That identity is what
|
|
makes the record size fall out of the data rather than being assumed.
|
|
1,270,802 vertices over 4,560 class spans; 116 spans carry no geometry.
|
|
Vertices are 16-byte VIF-packed half-float quads, handed back raw.
|
|
- [ ] `moby_anim` — **still open, and the obvious reading is ruled out.** An
|
|
instance table would have to scale with the level's moby class count, but
|
|
**per-chunk-type record counts are level-independent** -- the same types
|
|
report 90, 77, 50 and 47 on every level tried, and the largest type
|
|
totals 2,430 = 90 x 27. Nothing in the chunk set is keyed by moby class.
|
|
The types also pair up (two types both reporting 90 on every level,
|
|
another pair both 77), which looks like two views of one fixed table
|
|
rather than two independent tables.
|
|
- [x] `collision` — container framing and header fields. A 0x40-byte header
|
|
self-describes: it carries its own size and the payload size, and
|
|
`header + payload` stays inside `core_data` on all 27 levels. 41,481,520
|
|
payload bytes across 19 levels; 8 declare zero length. Header bytes `+8`
|
|
reads zero on 22 levels and a large value on 7/9/12/13/14; the payload's
|
|
two leading `u16` are non-zero on all 19 non-empty levels (1-74 and
|
|
13-112) and are reported as `CollisionHeader::first`/`::second`.
|
|
- [ ] The collision **cell layout is not decoded.** The payload does not walk
|
|
as fixed-stride cells. On level 4 a table starts at payload `+5932` and
|
|
runs **17 entries** -- deltas rise then fall -- against a 75-cell grid,
|
|
with no arithmetic relating the two. A 64-byte RAM stride looked promising
|
|
and is **disproved** -- the longest such run is 27 records of identity
|
|
matrices, one per level.
|
|
- [x] **The collision payload is essentially verbatim in RAM, not reshaped.**
|
|
Level 0's sits at RAM `0xac6800` for a disc address of `0x27e800`:
|
|
**903,212 of 903,248 bytes identical**, first difference at `+0xdc82c`, with
|
|
**6** bytes differing in the final 36. Asserted by a savestate-gated test
|
|
that compares the whole payload. This **overturns** the earlier claim that the grid dimensions
|
|
are absent from RAM: level 0's `11 x 33` are the first two bytes of that
|
|
block. The earlier negative came from searching for the dimensions as a
|
|
`u32` pair when they are two `u16`s -- a bad pattern, not a property of
|
|
the data. The payload contains ascending `u32` offset tables from `+1024`
|
|
onward, and disc-side decoding is no longer blocked on reshaping. See
|
|
`plan/pcsx2-verification.md`.
|
|
- [x] `occlusion` — the PVS grid. A z/y/x tree of u16 node offsets over 4x4x4-unit
|
|
cells, populated cells naming 128-byte masks. **412,521 cells over
|
|
140,939 masks** across the 24 levels that have one; the mask array ends
|
|
within 48 bytes of the block boundary on every level. 3 carry no occlusion
|
|
data, and an offset of 0 means *absent* rather than "at the start" — the
|
|
latter parses as a grid whose mask array happens to fit, which is how it
|
|
nearly went wrong.
|
|
- [x] `sky` — 149 sub-objects across all 27 levels, each with a count, a
|
|
four-float bounding sphere and texture dimensions. The offset table at
|
|
`+0x20` is self-limiting: entries run while strictly inside the region.
|
|
**The word at `+0x0c` is not a count** -- it disagrees with the table on
|
|
most levels and reads 196,617 on level 2 against 4 sub-objects.
|
|
- [x] The **overlay's load base is `field_00 - 16` = 1,735,792**, derived from
|
|
the overlay's own profiler table (whose absolute addresses point back at
|
|
its names, on all 27 levels) and **confirmed in RAM**: all four profiler
|
|
names land where the base predicts. Any overlay offset can now be carried
|
|
to a RAM address. The overlay is *relocated*, not copied: only 37.67% is
|
|
byte-identical at the base, so tables inside it move.
|
|
- [~] `volumes` — **still not identified, but a candidate exists.** Every level's
|
|
`gameplay.bin` carries a table of **144-byte float records** with world
|
|
positions at `+0x0c`, preceded by an all-zero record (levels 0-9: 23 to 612
|
|
records). That is the shape of a volume trigger region and it is not tied
|
|
to anything else in the file -- but camera bounds, spawn points and path
|
|
nodes would look identical, and there is no engine-side `Volume` string to
|
|
discriminate with. **Recorded as candidate, not volumes.** Two detector
|
|
bugs on the way are written up: a validity test that counted zero as
|
|
world-plausible scored zero-filled memory perfectly, and the 144-byte stride
|
|
rested on four eyeballed offsets that the gap histogram did not support.
|
|
A promising lead also failed: level 0's `data.bin` references one candidate
|
|
offset exactly once (chance ~0.003), but **none** of seven other levels'
|
|
candidates are referenced by their own `data.bin`, so the table is reached
|
|
by walking structure and nothing links it to volumes. Not located. Nothing examined so far presents itself as a
|
|
volume: `core_data`, the chunk region and `gameplay.bin` all yield
|
|
structures that are accounted for by something else.
|
|
- [~] `level_overlay` — header, constant block and level data parsed
|
|
(`gc_formats::overlay`, 27/27). `+0x10..+0x1220` -- 4,624 bytes -- is
|
|
byte-identical on every level; the word at `+0x0c` is **not** the file
|
|
length, falling below it on 17 levels and above on 10. The debug string
|
|
pool it opens with carries `Camera_CollPrimTest WARNING! - grid out of
|
|
bounds! (RAR)`, independent support for reading the collision payload's
|
|
two leading `u16`s as grid dimensions. `+0x00` **is** the load base of
|
|
the section this file is, `0x1A7C80`, constant on all 27 levels because
|
|
every level's `.lit` loads there. `+0x0c` is **not** the `.lit` size -- it
|
|
falls *below* the file length on 16 of 27 levels, by up to 8.9%, so it is
|
|
excluded by sign -- and it is still unnamed. **The remaining header words
|
|
are unnamed and the level-specific tail is not structured yet**; the
|
|
Phase 3 seven-section parser and relocation are untouched, though the
|
|
seven sections are now named (`lvl.vtbl`, `lvl.camvtbl`, `lvl.sndvtbl`).
|
|
- [x] **The post-shrub chunk container.** A 16-byte header, a 10-byte zero gap,
|
|
then offsets tagged `0xF0000000 | low24` resolving to `chunk_start + low`;
|
|
header byte 14 is the record count, equal to `offsets.len()` on 1,123 of
|
|
1,123 chunks across all 27 levels. **77 distinct chunk types, 1,509
|
|
chunks, 34,491 records.** Moby class IDs enrich at 9,493 hits against
|
|
246.1 expected with contiguous per-type arrays -- but the arrays land in a
|
|
different place for each type, so no single pooled scan finds them.
|
|
- [x] **Chunk record framing is closed**, but the uniformity claim in it is
|
|
**retracted**: only **257 of 1,509** chunks have a uniform record length, and
|
|
1,252 are variable within the chunk. "1,509 of 1,509" was `resolve` slicing
|
|
at the chunk's first offset delta and the predicate confirming the parser
|
|
back to itself. An earlier withdrawal ("variable-length was a pooled
|
|
artifact") was wrong too -- the records were always variable. The record's leading byte is a **per-chunk phase
|
|
counter** (`bucket_rule`, 1,262 of 1,509 chunks) and on **1,235** of them
|
|
*both* leading bytes encode the record's own index in mixed radix
|
|
(`index_rule`), so the leading bytes carry no per-record information.
|
|
- [x] **The loader's transformation, from PCSX2 RAM.** Disc offsets
|
|
`0xf0000000 | low24` are rewritten in RAM to absolute EE pointers
|
|
`0xf1850000 | low24` -- tag replaced by the chunk's load base, low 24 bits
|
|
untouched. The payload itself is copied **verbatim**. The index finding
|
|
is corroborated live: the byte at `+2` takes exactly `0, 16, ... 240`, the
|
|
16 values `index_rule` predicts.
|
|
- [x] **Corrected: a record starts two bytes before the table's offset.** The
|
|
`02 00` read in RAM as a loader-inserted prefix is the record's own
|
|
leading word, already on the disc at every record. The loaded table
|
|
simply points two bytes earlier than the disc's, at that word. It is a
|
|
field: uniform across a chunk's records on **1,439 of 1,509** chunks,
|
|
fixed within **all 71 types**, values `{1, 2, 4, 6, 8, 10}`. Disproved
|
|
readings: an entry count (57 distinct fractional "sizes") and a
|
|
distinct-leading-byte count (0 of 1,506 agree).
|
|
- [~] The chunk **record fields are not decoded**, and no type is named -- but the
|
|
stride table is now measured: **74 signatures, 55 distinct strides, 52..640,
|
|
every stride a multiple of 4**, and 73 of 74 signatures use a single stride.
|
|
The exception is pinned: `[75 42 ef f2 71 b5]` at strides `{76, 92, 104}`.
|
|
Asserted including the exception, so "every type is uniform" cannot rot.
|
|
A per-type layout found for one type (48 bytes of data then 60 permanently
|
|
zero) does **not** generalise -- 0 of 9 types fit that shape.
|
|
**65 of the 74 signatures are byte-identical in all 27 levels** (9 are
|
|
level-specific, 0 ragged), so most of the container is static game tables
|
|
rather than level content -- asserted. Consequence for method: the 65
|
|
cannot be decoded by comparing levels, because there is nothing to compare.
|
|
`[75 42 ef]` is both level-specific *and* the three-stride type, so it is
|
|
where per-type decoding should start -- and decoding it found a **parser
|
|
defect**: it makes three chunks per level, one of which has record offsets
|
|
stepping `92, 88, 84, 92, 92, 92, 84, 88` on every level. `resolve` slices
|
|
every record at the chunk's single stride, so four of the eight records
|
|
over-read by 4 and 8 bytes and include the next record's head. Records
|
|
still *start* correctly and bounds checking holds, so it is a data-correctness
|
|
bug, not a safety one. The "strides {76, 92, 104}" description is a
|
|
misdescription of three chunk shapes, one of them variable.
|
|
Measured across **all** chunks rather than that one signature, the pattern
|
|
is the norm: **1,252 of 1,509 chunks have non-uniform record offsets**,
|
|
across 66 of 74 signatures, with every deviation a word-aligned multiple of
|
|
4 and most exactly +/-4. **Which model this is remains open** -- genuinely
|
|
variable-length records and fixed records with inter-record padding produce
|
|
identical offset tables, and the offsets cannot tell them apart. A fix that
|
|
slices each record against its successor was written and reverted: it
|
|
implements one of the two models and the evidence does not establish it.
|
|
It also revealed that three tests asserting "1,509 uniform record length"
|
|
were passing only because the parser forced uniformity by slicing at a
|
|
single stride. Settling it needs a field whose end is independently
|
|
observable. The body
|
|
is dense (74% of `f32` reads plausible against a 49% random control) with
|
|
an index-like tail -- 12 of 163 `u16` slots in the largest type stay below
|
|
`0x1000` -- but **no count field** exists in the first 64 body bytes at any
|
|
width or stride tried. Only **9.4%** of `u16` slots are per-chunk constant,
|
|
so records are not templates.
|
|
- [x] **Moby class arrays are contiguous per type, and the pooled scan was
|
|
wrong.** See rule 3a in `AGENTS.md`: the original claim of a `u16` array at
|
|
slots 129-140 was the largest-stride type dominating an aggregate. Per
|
|
type, every one of the 26 places its array somewhere else.
|
|
|
|
**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 `$gp`-relative operands — then matching the masked words to find a
|
|
reference function's copy on another overlay.
|
|
|
|
- [ ] Port the masking and code-identity logic
|
|
- [ ] `Relocation::func` and `Relocation::data`
|
|
- [x] `$gp` for this game (`0x001AEFF0`, against R&C1's `0x166c00`) -- confirmed
|
|
by `OpenRAC/rac2-gc-decomp` `docs/LEVELS.md` for all 27 levels
|
|
- [ ] 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`. |