main
9
Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
 ReaperOfVeriod
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3a1156d8e1 |
The tfrag morph is not in the data block: positions are verbatim in RAM
The morph was recorded as unverifiable because "reading a weight back out of
RAM does not work -- the positions live inside regenerated VU packets". That
is right about the correspondence and wrong about the cause. The cause is
measurable, and it comes back clean:
patches 833
positions 40,600 disc == ram
positions identical 40,600
block bytes differing 166,465
inside a position unpack 0
inside another unpack 49,484
in a VIF command word 116,981
Range: level 0, all 833 tfrag patches, live PINE RAM against the disc. Two
independent measurements agree. Walking the VIF lists on both copies and
comparing parsed positions gives 40,600 identical and zero changed; a raw
per-byte diff of each patch's own extent classifies every differing byte, and
none of them is in a position unpack. The position ranges total 490,224 bytes.
So the blend is not precomputed into the geometry. The rewrites are packet
framing -- 70% command words -- plus other unpack payloads, which is the loader
rebuilding the VIF packet for the tier it selected while leaving the vertices
alone. The morph happens at draw time in the VU stream.
The standing note becomes a sharper one: there was never a correspondence
problem. The values were identical, so there was nothing to read.
gc-trace gains verify-morph, which does both measurements. TfragGeometry
gains position_ranges and other_ranges so the walk needed to classify a diff
is already paid for, and the ranges come from the same walk the rest of the
parse uses rather than a second one that could drift.
Per-patch extents are the gap to the next patch's data pointer. That is exact
and needs no guess about which header field marks a patch's end; the first
attempt at this compared each patch against the whole rest of the region and
reported 65 million differing bytes, which is what an unbounded comparison
looks like.
tfrag_positions_are_verbatim_and_the_rewrites_are_elsewhere is gated on
GC_SSTATE and asserts the four bounds, plus two guards: the rewrites must be
non-trivial (over 100,000 bytes) and mostly command words, so a RAM image that
was a verbatim copy of the disc -- which would make the zero look good for the
wrong reason -- fails instead.
Suite with the disc and GC_SSTATE: 68 disc tests, 156 gc-formats, 22
gc-trace, 23 gc-engine, 19 gc-game. Clippy clean.
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ReaperOfVeriod
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2f5979e652 |
Update the decomp; read .text, and fix the disassembler that made it unreadable
Vendored rac2-gc-decomp is 13 commits behind, 12,375 lines added, almost all src/.
It names no collision data structure, so the format is still not handed over. Two
things are usable, and one precondition had to be fixed first.
THE PRECONDITION: the disassembler was stopping after five instructions.
tools/overlay-anchors called disasm_all across the whole window, which halts at
the first word capstone will not decode. In code regions that is almost
immediately, so every window came back with a handful of instructions and I had
concluded there was nothing there. It now walks four bytes at a time, prints
.word for anything undecodable, and reports how many failed. That is the whole
reason the earlier attempts produced nothing -- not that the code was absent.
WHAT THE DECOMP'S ASSERT TABLE ACTUALLY GIVES
assert-message-names.tsv maps each assert name to an address. For level 0,
CameraCollPrimTestGridOutOfBounds is 0x002db350. That address is not the assert
call and not the string. It is:
0x002db350: jr $ra
0x002db354: addiu $sp, $sp, 0x70
an epilogue. The address lands on the last group of the function before it, and
0x002db35c is a fresh prologue. It is also in .text (0x002a3b80..0x00447900),
five megabytes from the .lit string at 0x001a8998 -- which explains the "$gp search
returns zero" result from the other side. The string and the code are in different
sections, five megabytes apart.
WHAT IS ACTUALLY THERE
Immediately before the epilogue:
0x002db2dc: lwc1 $f20, 0xc($s0)
0x002db2ec: add.s $f20, $f20, $f21
0x002db2f0: c.olt.s $f0, $f20
0x002db304: jal 0x2db4b8 <- the assert call
0x002db314: lw $v0, ($s1) <- a count
0x002db31c: slt $v0, $s2, $v0
0x002db320: bnez $v0, 0x2db2cc <- loop back
0x002db324: addiu $s0, $s0, 0x30 <- stride 48 bytes
A loop over 48-byte records, reading a float at +12 and accumulating, bounded by a
count, with f22 set to 1.0f just above it -- a minimum-height clamp.
NOT CLAIMED to be the collision grid. It is a strided float loop beside an assert
the decomp labels CameraCollPrimTestGridOutOfBounds. A plausible address near a
plausible assert is a lead, not an identification, and that is the exact gap this
log keeps tripping over. Confirming it means tracing the function's arguments back
to the collision payload and showing the grid's leading u16s -- level 0 is 11 x 33
-- drive the count at ($s1). Not done, and not asserted.
The undecodable words are VU1 microcode (COP2 opcodes), which is expected: the
function interleaves VIF-fed VU1 work with FPU arithmetic, like tfrag's.
Tools build, clippy clean, 260 tests.
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ReaperOfVeriod
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4abce518e5 |
Decode the overlay's load base, from its own profiler table
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. |
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ReaperOfVeriod
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282e633a7c |
Withdraw the collision anchor: it was a byte-order bug in my own search
Last commit claimed exactly one GP-relative occurrence of the collision assert
string's $lo half, at 0x354cc8, and called it an unambiguous anchor. That was
wrong, and building the disassembler is what proved it.
The search compared word bytes 1..3 against the 16-bit immediate. The PS2's MIPS
is little-endian, so an I-type immediate sits in bits 15..0 -- word bytes 0 and
1. Bytes 1..3 are the opcode, $rs and $rt fields. The match was on those.
The instruction at the phantom hit is 0x24a89948:
addiu $t0, $a1, -0x66b8
whose real immediate is 0x9948 -- ten bytes from the 0x99a8 being searched for.
-0x66b8 merely looks like a plausible $gp offset, which is what made it
convincing. With the byte order corrected the count is ZERO, in 2,751,268 bytes.
So the anchor is not established and the assertion is withdrawn. What survives is
still worth having: the functions are named (Camera_CollPrimTest takes (prim,
grid)), $gp = 0x1AEFF0, .lit loads at 0x1A7C80, and the assert string is a unique
copy at overlay+0xd18.
Probably the code reaching that string does not address it through $gp, or
reaches a copy in another section. The decomp's assert-message-names.tsv gives
0x002db350 for level 0 -- inside .lit, but it disassembles to a function epilogue
(jr $ra / addiu $sp, $sp, 0x70), so those are code locations, not string
addresses, and they are not traced to the assert either.
tools/overlay-anchors now does the search with the correct byte order and
carries a comment on exactly the part that was wrong, because that is the part
that will be re-derived otherwise. It also disassembles around an address:
cargo run -q -p gc-overlay-anchors -- <overlay.bin> --disasm 0x2db350 0 64
The useful general lesson, which the roadmap already says and this is a second
demonstration of: a probe that returns a small, clean, narratively satisfying
number is the most dangerous kind of wrong result. "Exactly one hit in 2.75 MB"
read as conclusive. It was an artifact of comparing the wrong two bytes, and it
survived a commit because it fit the story.
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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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54862b64ee |
Identify the tie record as RAC1's TiePacketHeader, and retract a formula
The 16-byte tie record is R&C1's TiePacketHeader offset for offset: a data pointer at +0, then R&C1's byte fields at +4 through +0x10. The identification is not a resemblance but R&C1's own rule -- bfc_distance == 5 * shader_count -- holding on all 15,219 records of all 2,177 blocks on all 27 levels. Measured over the same set, and reported rather than asserted where it is not universal: bfc_distance == 5 * shader_count 15219 / 15219 vert_ofs <= vert_size all scissor_size <= scissor_ofs all control_size <= control_count all color_ofs == vert_size 12640 / 15219 color_ofs == vert_ofs + vert_size 0 / 15219 color_count, strip_count, strip_vertex_count zero 15089 / 15077 / 15078 R&C1's rule for the colour offset holding on none of them is the interesting line: the two games use that field differently, so it is named color_ofs for what this game's majority reads as and the 2,579 exceptions are counted rather than averaged away. TieRecord parses all twelve fields, invariants_hold asserts only the universal four, and the disc test counts the rest. A packet-length formula is withdrawn rather than softened. (vert_ofs + vert_size + scissor_ofs + scissor_size) * 16 was measured at 61 of 61 pairs and is not reproduced on the correct blocks -- 0 of 13,042. The block set was the error, not the arithmetic: the script that produced the 61 read packets[2] where packets[1] was meant, so it measured 461 blocks instead of the 2,177 the class tables define, and the formula agreed perfectly with a population that was not the tie blocks. TieRecord::packet_bytes goes with it, and the retraction is recorded in the format doc and in the struct. That misread also explains why the earlier RAM verification saw different numbers for the two inputs -- same lesson as rule 3, arriving through a wrong subscript instead of a wrong span. |
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ReaperOfVeriod
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4e90c282ad |
Make the tie record relocation a command, and verify it on two levels
The relocation rule from the previous commit was established by a script that lived in a shell history, which means the next person would have had to rediscover it. It is now `gc-trace verify-tie-records <unpacked-dir> <level> <class> <lod> <src>`: resolve the class, parse the block, search the RAM image for the loaded record table, report what it found, and exit 0 only when every record's pointer has become table + word and every field byte is verbatim. Swept over every (class, lod) slot of two levels, from PCSX2 savestates: level 0: 87 slots with a block, 87 verified, 0 mismatched, 61 absent level 1: 104 slots with a block, 104 verified, 0 mismatched, 78 absent So the rule holds on every LOD block of two levels the game had loaded, which is what makes the record layout a finding rather than a reading of one block. Writing the command also caught an off-by-one in the parser it exercises: TieBlockHeader::records started its slice after the 16-byte header, but the header IS the first record -- the table runs from the block start to data_offset, and a block with data_offset 0x50 holds five records, the first being the header itself and its pointer naming where the payload begins. Found because the tool's first run relocated nothing while the same check in a script had passed; the unit test fixture was wrong in the same way and is fixed. Two operational notes now in the format doc: the live emulator is not a stable input (verifying level 1 over PINE matched 104 of 104 while the user was on that planet, and the same command minutes later found no matching copy because they had returned to level 0 -- a miss there is not a counterexample, so the report says "no copy matched" rather than "failed"), and a class index past the table count is an error rather than a mismatch, so a sweep should stop at the level's class count rather than a round number. |
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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. |