main
3
Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
 ReaperOfVeriod
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1f903efe23 |
An external decomp turns two overlay constants from measured into named
OpenRAC/rac2-gc-decomp is the same disc as ours, verified rather than assumed:
ours 3,828,350,976 9db2e33e...b1ce5
theirs 3,828,350,976 9db2e33e...b1ce5
Vendored read-only under vendor/ (already gitignored) and added to PROVENANCE.
It names two constants this parser had measured but never explained:
* overlay.bin +0x00 = 1,735,808 = 0x1A7C80, the .lit load base. It is constant
across all 27 levels because every level's literal section loads at the same
address. So the first header word is the load base of the section the file IS,
which also establishes that overlay.bin is that section -- it holds both code
and the debug string pool. $gp = 0x1AEFF0 comes with it, and that closes the
roadmap's open "$gp for this game" item.
The program around it is seven sections -- .lit .bss .data vtbl camvtbl sndvtbl
.text -- which is precisely the "seven-section parser and relocation" Phase 3
item for this format. Known target now rather than a guess.
I then tested the obvious follow-up and it is wrong: if +0x00 is the .lit load
base, +0x0c ought to be the .lit size. It is SMALLER than the file on 16 of 27
levels, by up to 8.9% (level11: file 3,151,128 vs 2,870,792). Excluded by sign,
not by a near miss. Still unnamed.
Collision: still blocked, but no longer blocked on tooling. The decomp names
Camera_CollPrimTest(void *prim, void *grid) without decompiling it, so the cell
layout is not handed over. What it does supply is $gp, and that is enough to
start. "Camera_CollPrimTest WARNING! - grid out of bounds! (RAR)" is at
overlay+0xd18, the only copy in the file, so:
string overlay+0xd18 -> RAM 0x1a8998; delta to $gp -0x6658; $lo 0x99a8
MIPS puts the $lo half in bytes 1..3 of a 4-byte instruction. Searching the whole
overlay instruction-aligned gives exactly ONE hit:
0x354cc8 (overlay+0x1ad048)
One occurrence in 2.75 MB of code is unambiguous: that is the instruction
materialising the assert string, and its enclosing function is
Camera_CollPrimTest. That is the route in, and it needs no symbols.
tools/overlay-anchors does this step, dependency-free. I started this with
capstone for the disassembly proper and dropped it: capstone 0.14 does not
re-export Mode/Endian from a public path, and an excluded-from-the-workspace
native dependency is a poor trade for a step that does not need one yet. The
anchor search is pure byte work, so it is pure Rust. No native dependency is
added anywhere, and the tool is an ordinary workspace member.
Surveyed the rest of that project against our open items: no volume structures,
no tie vertex layouts, no SBlk/DAW fields, no wavelet tables. It is a guide to
the code, not a replacement for reading it.
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ReaperOfVeriod
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69a8398f6e |
Verify the tfrag lighting magnitudes against the running game
The harness that compares the port against the game's own memory existed but had never been compiled: tools/trace did not build (27 errors, all in the argument plumbing), and the tfrag_light.rs light-bank correction it motivated was unverified. This finishes it and runs it, and the run finds two real bugs. Result, on level 0 against three inputs -- the live emulator over PINE and two PCSX2 savestates from the same level, agreeing byte for byte: headers matching the disc on invariant bytes: 833/833 data pointers relocated as table + disc offset: 833/833 light bank in RAM at 0x50ab20, byte-identical to the disc's vertices compared: 40600 (162400 colour bytes) equal: 162400 (100.00%) The locator finds the level's tfrags block in RAM by tfrag 0's bounding sphere and accepts a candidate only when every header matches the disc on the bytes the game leaves alone and every data pointer is the relocated form, so "the block was found" is itself a verification rather than an assumption. The bank is searched in RAM by its exact section bytes, which is what settles its framing: offset at +0x04, an i32 set count, twelve bytes of pad, then the sets. The previous reading (offset at +0x00, count at +0x04) was wrong. Two bugs the comparison found, both of which produced plausible output: 1. vertex_normal_bits negated x and y and left z positive, while NormalTable::normal negates all three. dA came out -0.707 where the game had +0.707, so max(dA, dA*wA) took the wrong branch and every vertex lit near its base colour: dark, but not wrong-dark. 95.88% agreement with the bug, 100.00% without. 2. A record whose select names a set the bank lacks drew transparent black. The game writes the record's base colour; 3,130 of level 0's 40,600 vertices do this (select 0x000f, set 15 -- a runtime slot the level's directional bank does not have). The vertex is unlit, not invisible. Both are now regression tests in the engine. The comparison prints the pass's per-vertex terms (light_vertex_terms) for the first mismatches, because a colour mismatch alone cannot be attributed and the comparison is worthless without attribution -- that is how the second bug was identified from a three-line read rather than guessed at. Docs: docs/plan/pcsx2-verification.md records the harness, the result, the two bugs and what to compare next; roadmap and level-assets.md stop carrying lighting magnitudes as an open item. Findings reach tests only as numbers -- no test reads a savestate, a dump or a live emulator. |
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ReaperOfVeriod
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a02f79a6d1 |
Initialise native Rust port of Ratchet & Clank: Going Commando
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. |