ReaperOfVeriod
a02f79a6d1
Sets up the foundation for reimplementing the PS2 game in Rust rather than emulating it. Nothing is implemented yet; this is the scaffold, the verified target and the working agreements that keep a long project coherent. Target disc, verified against a real image: SCUS_972.68 v1.01, USA Black Label, NTSC 60 Hz boot ELF 2,618,684 bytes, SHA-1 bacda860...d098a77, entry 0x00131AE8 The entry point independently matches the value recorded by the rac2-gc-decomp community reference, which cross-confirms the identification. This is the exact build the upstream research pins; Greatest Hits v2.00 is a different binary and is not the target. NTSC matters beyond label compatibility: PAL discs run 50 Hz, which would make chargeboots and other speed-sensitive movement run at 5/6 speed. Verifying the disc before writing movement code avoids discovering that in Phase 5. Contents: - Five-crate workspace (formats, extract, game, video, engine) on Bevy 0.19.1, matching the version ReRAC uses so its Graphics Synthesizer and VU work stays portable. `cargo check --workspace` is clean. - tools/identify-disc.py, which reproduces the identification against any disc image and distinguishes a truncated dump from a non-PS2 image. - .githooks/pre-commit, refusing game data from entering git history: disc image extensions, asset directories, container signatures at offset 0, and files over 50 MiB. Verified against seven cases including a disc image renamed to look like source. Now that this pushes to a remote, this matters more than it would have locally. - AGENTS.md, the operating agreements: no game data ever, reproduce the PS2 float model rather than approximating it, bound every read, verify against the real disc. - PROVENANCE.md, recording that this follows ReRAC (ISC) and learns from rac2-gc-decomp (MIT). Wrench is used as a written specification only and no GPLv3 code is copied, since that would relicense everything derived from it. RAC2Decomp is explicitly not used: its provenance is disputed in the upstream community reference, and it targets the wrong region. - docs/roadmap.md, phased so the riskiest unknowns are retired early. The two that matter: overlay relocation transfers from ReRAC and makes 27 level overlays tractable, while VU1 microcode is binary and is the hardest single item. Phase 5 is a deliberately scoped Veldin vertical slice as the go/no-go.
194 lines
7.1 KiB
Markdown
194 lines
7.1 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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- [ ] Nothing else implemented yet
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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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**Goal:** turn the disc image into verified, unpacked asset files.
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- [ ] `iso9660` reader (R&C2 lists assets as real files, unlike R&C1)
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- [ ] `RC2.HDR` table of contents parser (408,444 bytes at disc root)
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- [ ] WAD LZ77 decompression
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- [ ] Unpack global WADs (`G/*.WAD`) and per-level WADs
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- [ ] Commit a size+SHA-1 table per target file (hashes only, never content)
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- [ ] `verify` stage
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**Gate:** every extracted file matches the committed hash table, and the
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decompressed size of every WAD stream matches its header.
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**Note:** the three MPEG WADs total roughly 2.4 GB of the 3.8 GB disc. Video is
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a data problem before it is a decoding problem — plan to stream.
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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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- [ ] `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`. |