ReaperOfVeriod
2a5307a157
The block header's float at +0x08 gives L and the switch distances are [D0, D1, D2] = [6L, 4L, 2L] world units -- 192/128/64 on every level measured. The distance test uses the patch's bounding sphere truncated to integers against trunc(D * 1024), not the sphere's centre, so a patch straddling a threshold takes the coarser mode. Six modes result: LOD 2, LOD 1 collapse, LOD 1 morph, LOD 0 collapse, LOD 0 morph, LOD 0. A morph weight runs 0 to 1 across its tier's band. Past the far edge an entry is not blended but replaced by its first parent -- a collapse. The tested property is that distance never moves back to a finer mode, swept across the whole range, because that is what keeps terrain from popping as the camera moves. The four V4_8 parent arrays are classified by VU address and an unrecognised address is now an error, which is a real check: all 18,102 patches still parse. Every recorded parent resolves to real vertex info and real positions, and no common entry claims a parent. That is as far as it goes, and the limit is a finding rather than a rounding error. The addresses are not unique: on level 0 patch 1, unk_indices_2_lod_01_addr == parent_indices_lod_0_addr == 291, with unk_06 and unk_0a both zero, so nothing but unpacking order separates them. Across all 27 levels 57,782 of 374,349 LOD entries resolve, and 316,548 unresolved LOD-0 entries against 28,739 resolved is far too lopsided to be genuine -- either the arrays are misassigned where addresses collide, or RAC2's positions_lod_0_count means something other than RAC1's. Only 3,274 of 18,102 patches carry enough V4_8 bytes to cover positions_lod_01_count + positions_lod_0_count + extras. The vertex-info tiers themselves are confirmed: the addresses at +9 and +11 match the observed V4_16 unpacks and the three tier counts sum to vert_count on every patch, so the header layout is right and it is specifically the parent arrays that are open. Ruled out so far: address-only classification (collides) and one-parent-per-position (fails on 15,000 patches). Not yet tried: ordering by VU address instead of by declaration, and using unk_06/unk_0a to suppress an empty tier before falling through. Written up in plan/level-assets.md.
284 lines
13 KiB
Markdown
284 lines
13 KiB
Markdown
# Roadmap
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Status as of **2026-10-09**.
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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: 5,186 files, 5,685,541,143 bytes, every
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one of the 92 asset containers parsing.
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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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- [ ] Next: tfrag parent indices, then the first drawable frame.
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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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- [ ] `core_index` class tables — the header base is confirmed (the compressed
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and decompressed sizes of `core_data` sit at the same offsets in all 27
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levels), and every offset lands inside `core_data`. But the class-table
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fields do not decode under any field order or stride tried. Ruled out and
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written up in `plan/level-assets.md`. Next: identify `tfrag` by its own
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structure instead of through the header.
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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] **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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- [ ] tfrag parent indices: the four V4_8 arrays are classified by VU address,
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but the addresses collide (`unk_06` and `unk_0a` are zero, so an absent
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tier shares the next one's address). 57,782 of 374,349 LOD entries
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resolve; the 316,548 unresolved LOD-0 entries are far too lopsided to be
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genuine. Tried and ruled out in `plan/level-assets.md`.
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- [ ] `gameplay` — begins `WAD` + a per-level byte, and does *not* decode with
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the WAD LZ77 decoder. All 27 levels fail identically, so the input is
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wrong rather than the decoder. Ruled out: bit order, header length, the
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LZ77 framing. Hypotheses queued in `plan/level-assets.md`.
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- [ ] `occlusion` — 2 to 25 sectors, small enough to read whole.
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- [ ] `sound_bank` — `SBlk` and `DAW` signatures found in all 27.
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- [ ] `data` — the large one: 4.2 to 21.9 MB of geometry per level.
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- [ ] `tfrag` — terrain: LOD chains, strips, morph targets
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- [ ] `tie` — instanced environment geometry, fat vertices
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- [ ] `shrub` — foliage and decorative meshes
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- [ ] `moby` — dynamic actors; `moby_anim` — skeletal animation
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- [ ] `collision` — cells, packed vertices, faces
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- [ ] `occlusion` — the PVS grid
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- [ ] `sky`, `volumes`, `textures` (CSM1 CLUT + PS2 alpha)
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- [ ] `level_overlay` — the seven-section parser and relocation from Phase 3
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**Gate:** every parser has a golden test against bytes from the real disc, and
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reports mismatched header counts as failures rather than warnings.
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**Discipline:** bound every read. Typed errors, no panics, no reads past the
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buffer.
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---
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## Phase 3 — Overlay system
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**Goal:** make 27 level overlays tractable.
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Every overlay carries the same seven sections (`.lit`, `.bss`, `.data`,
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`lvl.vtbl`, `lvl.camvtbl`, `lvl.sndvtbl`, `.text`) and the same engine code,
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linked at different addresses. ReRAC solves this by masking relocations — `j`/
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`jal` targets, `lui` immediates of main-RAM addresses, the `%lo` that completes
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them, and `$gp`-relative operands — then matching the masked words to find a
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reference function's copy on another overlay.
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- [ ] Port the masking and code-identity logic
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- [ ] `Relocation::func` and `Relocation::data`
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- [ ] `$gp` for this game (`0x001AEFF0`, against R&C1's `0x166c00`)
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- [ ] Extend the level table from 19 to 27
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**Gate:** every level-01 function's relocated copy is found on all 27 overlays;
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cross-checked against an independent cluster hash.
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**Why this is high-value:** it turns "27 overlays of unknown code" into a table
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lookup, and it is the main thing inherited from ReRAC.
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---
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## Phase 4 — Engine core
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**Goal:** draw a frame.
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- [ ] Graphics Synthesizer in wgpu, with the GS's own rules: its
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`round(log2(z/n) + K)` mip selection, blend and alpha-test behaviour,
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alpha `0x80` meaning 1.0, CLAMP wrap
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- [ ] VU0/VU1 skinning and lighting on the PS2 float model
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- [ ] LOD/morph/cull per `TfragProc` and `TieProc`
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- [ ] Occlusion culling, fog, shadows
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- [ ] GIF/VIF packet stream interpretation
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**Gate:** CPU and GPU paths agree on every vertex of a reference level — the
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same identity check ReRAC runs.
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**Risk:** VU1 microcode is **binary** in the game's `.vutext` section, so it is
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reverse engineered rather than parsed. This is the hardest single item in the
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project and the main threat to the timeline. Note that ReRAC's own moby VU1
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analysis trips their disassembler on two opcodes.
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---
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## Phase 5 — Veldin vertical slice
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**Goal:** one planet, playable start to finish.
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- [ ] Ratchet's controller on a **spherical** planet
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- [ ] Chargeboots: hold/release timing, chained jumps, dash
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- [ ] Wrench and the camera
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- [ ] Collision and the HUD
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**Gate:** Veldin is completable and visually matches PCSX2 frame-for-frame under
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replayed input.
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**This is the go/no-go for the project.** If Veldin works, the other 26 levels
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are content. If it does not, the reason is discovered while it is still cheap.
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Spherical gravity is the thing most likely to break, because it invalidates
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R&C1's movement and camera assumptions wholesale.
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---
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## Phase 6 — Remaining overlays and the shell
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- [ ] Per-level moby class dispatch via `lvl.vtbl`
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- [ ] Remaining 26 levels
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- [ ] Planets, travel, the Gadgetron vendor, RPG upgrades
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- [ ] Weapon modification bitmasks (lock-on, shock, acid, …)
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- [ ] Minigames and challenges
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- [ ] The 25-state memory-card FSM and its UI
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- [ ] IFF chunk saves, including import of a R&C1 save to unlock legacy weapons
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---
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## Phase 7 — Audio and video
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- [ ] 989snd v2 audio decode and playback (not CRI ADX — a different codec)
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- [ ] SPU2 mixing, reverb zones, level sounds
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- [ ] IPU/MPEG-2 video for the title screen and cutscenes
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---
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## Phase 8 — Fidelity pass
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Differential testing against PCSX2 across every level:
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- [ ] Recorded-input frame comparison, per planet
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- [ ] Geometry, fog, blend, alpha, texture sampling
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- [ ] Audio sync and 60 Hz timing
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- [ ] Behavioural comparison: traversal routes, boss timing, RNG
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---
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## Principles
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- **A gate is pass/fail, not a percentage.** "Looks fine" is not progress.
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- **Negative results are written down.** A ruled-out approach saves the next
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attempt as much as a working one.
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- **The float model is not negotiable.** Approximate is not the same as
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faithful, and the difference is visible in how the game feels.
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- **Fidelity over tidiness.** Where the original does something that looks like
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a bug, reproduce it and say why in a comment. See `AGENTS.md`. |