ReaperOfVeriod/Going-Commando
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity
Files
55ea619b4cf80efd87360dd289f2b6bef60ca38a
Going-Commando/crates/gc-extract/tests/disc.rs
T
ReaperOfVeriod 55ea619b4c Decode the tie class header's +0x0c word: three LOD record counts 
Range measured: every tie class on the disc, 1,864 classes over all 27 levels.

Method: read the word at class +0x0c as four bytes, and read the record counts
independently from the blocks themselves -- follow packets[lod] to the block,
walk to the 0xf6 terminator, and count the 16-byte records the block header's
data_offset names. Two paths to the same number, so the check is not circular.

Result: the byte at +0x0c is the LOD 0 record count, +0x0d is LOD 1's and +0x0e
is LOD 2's, on 1,864 of 1,864 classes. Classes with an absent LOD agree too:
a zero packets[lod] gives a zero count and the byte is zero.

This closes the file's oldest lie about the tie header. The comment in
TieClassHeader::parse read "0x0c: the 64 light-slot normals offset. Read past,
not decoded" -- inherited from R&C1's layout, where the word genuinely is an
offset. On R&C2 it is not an offset at all; it is three counts, and R&C1 carries
the same quadruple at +0x20. Skipping the field was the right action on the
wrong information: the field was unknown only because R&C1's map was applied to
R&C2's bytes.

TieClassHeader gains packet_counts, and
tie_class_header_counts_records_per_lod asserts the agreement.

The fourth byte, +0x0f, is left unnamed. It ranges 1..15, and the obvious
following of R&C1 -- the shader/ad-gif total -- disagrees on 1,827 of 1,864
classes, which is 2% agreement where a count would expect 100%. It is recorded
as unidentified rather than given a name that fits a fiftieth of the population.
2026-10-13 08:59:40 +02:00

4929 lines
190 KiB
Rust
Raw Blame History

//! Integration tests against a real disc image.
//!
//! These are skipped unless `GC_DISC` points at a legally obtained disc, since
//! the repository must not contain game data. When it is set they check the
//! identification and unpack results against the committed hash table.
//!
//! ```sh
//! GC_DISC="path/to/disc.iso" cargo test -p gc-extract --test disc
//! ```
use std::collections::BTreeSet;
use std::path::{Path, PathBuf};
/// The disc under test, if the environment names one.
fn disc() -> Option<PathBuf> {
let p = std::env::var_os("GC_DISC")?;
let p = PathBuf::from(p);
p.is_file().then_some(p)
}
/// Skip a test with a clear reason rather than failing.
macro_rules! require_disc {
() => {
match disc() {
Some(p) => p,
None => {
eprintln!("skipped: set GC_DISC to a Going Commando disc image to run this");
return;
}
}
};
}
#[test]
fn identifies_the_supported_build() {
let path = require_disc!();
let info = gc_extract::identify::identify(&path).expect("disc should identify");
assert_eq!(info.serial, "SCUS_972.68");
assert_eq!(info.volume_id, "RATCHETANDCLANK2");
assert!(
info.is_target(),
"expected the supported build, got: {}",
info.verdict()
);
assert_eq!(
info.boot_elf_sha1,
gc_extract::identify::TARGET_BOOT_ELF_SHA1,
"boot ELF SHA-1 differs from the recorded retail value"
);
assert_eq!(info.boot_elf_size, 2_618_684);
// This disc is NTSC; the movement constants assume 60 Hz.
assert!(!info.is_pal(), "test disc should be NTSC");
}
#[test]
fn agrees_with_the_python_reference_identifier() {
let path = require_disc!();
let info = gc_extract::identify::identify(&path).expect("disc should identify");
// tools/identify-disc.py is the reference implementation and prints these
// two values. If they ever disagree, one of them has a bug.
// Run from the workspace root so the relative path to the tool resolves.
let root = std::path::Path::new(env!("CARGO_MANIFEST_DIR"))
.parent()
.and_then(|p| p.parent())
.expect("the crate should live two levels below the workspace root")
.to_path_buf();
let py = std::process::Command::new("python3")
.arg(root.join("tools/identify-disc.py"))
.arg(&path)
.current_dir(&root)
.output()
.expect("python3 should be available to run the reference identifier");
assert!(
py.status.success(),
"the reference identifier failed:\n{}",
String::from_utf8_lossy(&py.stderr)
);
let text = String::from_utf8_lossy(&py.stdout);
assert!(
text.contains(&format!("serial {}", info.serial)),
"serial disagrees with the reference identifier:\n{text}"
);
assert!(
text.contains(&format!("SHA-1 {}", info.boot_elf_sha1)),
"boot ELF SHA-1 disagrees with the reference identifier:\n{text}"
);
}
#[test]
fn unpacks_and_matches_the_committed_table() {
let path = require_disc!();
let table_path = Path::new(env!("CARGO_MANIFEST_DIR")).join("data/gc-files.tsv");
let table_text =
std::fs::read_to_string(&table_path).expect("the hash table should be committed");
let expected = gc_extract::verify::parse_table(&table_text);
assert!(
expected.len() > 5000,
"expected a full table, got {} rows",
expected.len()
);
// Unpack into a temporary directory so the test leaves nothing behind.
let tmp = std::env::temp_dir().join(format!("gc-unpack-{}", std::process::id()));
let _ = std::fs::remove_dir_all(&tmp);
std::fs::create_dir_all(&tmp).expect("should create a temp directory");
let files = gc_extract::unpack::unpack(&path, &tmp).expect("unpack should succeed");
// Every unpacked file must match the recorded size and hash.
let report = gc_extract::verify::verify(&tmp, &expected);
let _ = std::fs::remove_dir_all(&tmp);
assert!(
report.ok(),
"unpacked data does not match the committed table:\n{}",
report.summary()
);
assert_eq!(
files.len(),
expected.len(),
"unpack produced a different file count"
);
}
#[test]
fn every_container_parses() {
let path = require_disc!();
let iso = gc_formats::iso9660::IsoImage::open(&path).expect("ISO should open");
let containers: Vec<_> = iso
.files
.iter()
.filter(|e| e.name.starts_with("G/") && e.name.ends_with(".WAD"))
.collect();
// 92 `G/*.WAD` containers: 27 LEVEL, 27 AUDIO, 27 SCENE, 11 globals.
assert_eq!(containers.len(), 92, "expected 92 asset containers");
// MPEG1 and MPEG2 are raw video streams with no table; the other 90 must
// all parse as indexed containers.
let raw_video: Vec<&str> = containers
.iter()
.map(|c| c.name.as_str())
.filter(|n| *n == "G/MPEG1.WAD" || *n == "G/MPEG2.WAD")
.collect();
assert_eq!(
raw_video.len(),
2,
"expected MPEG1 and MPEG2 to be the raw streams"
);
// The per-level families must all be present, at 27 each.
for family in ["LEVEL", "AUDIO", "SCENE"] {
let n = containers
.iter()
.filter(|c| {
let stem = c.name.trim_start_matches("G/").trim_end_matches(".WAD");
stem.strip_prefix(family)
.map(|rest| !rest.is_empty() && rest.chars().all(|ch| ch.is_ascii_digit()))
.unwrap_or(false)
})
.count();
assert_eq!(n, 27, "expected 27 {family}<n>.WAD containers, found {n}");
}
for entry in &containers {
if raw_video.contains(&entry.name.as_str()) {
continue;
}
let data = gc_formats::iso9660::read_at(&path, entry.lba, entry.size)
.expect("read should succeed");
let kind = gc_formats::global_wad::RangeKind::for_container(&entry.name);
let container = gc_formats::global_wad::GlobalWad::parse_with(&data, kind)
.unwrap_or_else(|e| panic!("{} failed to parse: {e}", entry.name));
assert!(
!container.entries.is_empty(),
"{} parsed but had no entries",
entry.name
);
}
}
/// The level container header is the first typed structure we parse from real
/// data, and the tiling invariant is the check that holds on every level rather
/// than one hand-picked sample.
#[test]
fn level_headers_tile_their_containers() {
let path = require_disc!();
let iso = gc_formats::iso9660::IsoImage::open(&path).expect("ISO should open");
let mut checked = 0;
for entry in iso.files.iter().filter(|e| e.name.starts_with("G/LEVEL")) {
let data = gc_formats::iso9660::read_at(&path, entry.lba, 0x60).expect("read header");
let h = gc_formats::level_wad::LevelHeader::parse(&data)
.unwrap_or_else(|e| panic!("{}: {e}", entry.name));
assert_eq!(h.header_size, 0x60, "{}", entry.name);
assert_eq!(
h.runtime_sector, 0,
"{}: runtime sector field should be 0 on disc",
entry.name
);
// Every present extent must start where the previous one ended.
let extents = h.ordered_extents();
for w in extents.windows(2) {
let (pn, p) = w[0];
let (nn, n) = w[1];
assert_eq!(
p.offset + p.size,
n.offset,
"{}: gap or overlap between {} and {}",
entry.name,
pn.name(),
nn.name()
);
}
// Nothing may fall outside the container. The last extent may end one
// sector past the file end through sector rounding, hence `+ 1`.
let container_sectors = (entry.size / 2048) as i32;
for (name, r) in &extents {
assert!(
r.offset >= 0 && r.offset + r.size <= container_sectors + 1,
"{}: {} extent {:?} is outside the container ({container_sectors} sectors)",
entry.name,
name.name(),
r
);
}
checked += 1;
}
assert_eq!(checked, 27, "expected 27 level containers");
}
/// Level ids are not file order: `LEVEL21.WAD` reports 30. Anything that keys
/// off the container index would silently mislabel that planet.
#[test]
fn level_ids_are_not_container_indices() {
let path = require_disc!();
let iso = gc_formats::iso9660::IsoImage::open(&path).expect("ISO should open");
// The ISO filesystem lists names alphabetically, so LEVEL10 sorts before
// LEVEL2. Order by the numeric suffix, which is what the container names
// mean.
let mut levels: Vec<(usize, &gc_formats::iso9660::DirEntry)> = iso
.files
.iter()
.filter(|e| e.name.starts_with("G/LEVEL"))
.map(|e| {
let n: usize = e
.name
.trim_start_matches("G/LEVEL")
.trim_end_matches(".WAD")
.parse()
.expect("level container names end in a number");
(n, e)
})
.collect();
levels.sort_by_key(|(n, _)| *n);
let mut mismatches = Vec::new();
for (index, (_, entry)) in levels.iter().enumerate() {
let data = gc_formats::iso9660::read_at(&path, entry.lba, 0x60).expect("read header");
let h = gc_formats::level_wad::LevelHeader::parse(&data).expect("parse");
if h.id as usize != index {
mismatches.push(format!(
"{}: id {} but is container {index}",
entry.name, h.id
));
}
}
// Exactly one level is out of step: the gap left by a removed level.
assert_eq!(
mismatches.len(),
1,
"expected exactly one level whose id differs from its container index, got {mismatches:?}"
);
assert!(
mismatches[0].contains("LEVEL21"),
"unexpected mismatch: {mismatches:?}"
);
}
/// Sizes in the level header are sector counts. If they were byte counts, the
/// extents could not tile a container this size, so this also guards against
/// "fixing" the parser to read them as bytes.
#[test]
fn level_extent_sizes_are_sector_counts() {
let path = require_disc!();
let iso = gc_formats::iso9660::IsoImage::open(&path).expect("ISO should open");
let entry = iso.find("G/LEVEL0.WAD").expect("level 0");
let data = gc_formats::iso9660::read_at(&path, entry.lba, 0x60).expect("read header");
let h = gc_formats::level_wad::LevelHeader::parse(&data).expect("parse");
// Sound bank occupies sectors 1..735 and data 735..7219.
assert_eq!(h.sound_bank.offset, 1);
assert_eq!(h.sound_bank.size, 734);
assert_eq!(h.data.offset, 735);
// Read as bytes, 734 would be under four sectors and the tiling would break.
assert_eq!(h.sound_bank.byte_len(), 734 * 2048);
}
/// The level data extent is a container of byte ranges. Its header locates the
/// geometry index and the compressed geometry, and every range must lie inside
/// the extent on all 27 levels.
#[test]
fn level_data_extents_are_in_range() {
let path = require_disc!();
let iso = gc_formats::iso9660::IsoImage::open(&path).expect("ISO should open");
let mut checked = 0;
for entry in iso.files.iter().filter(|e| e.name.starts_with("G/LEVEL")) {
let raw =
gc_formats::iso9660::read_at(&path, entry.lba, entry.size).expect("read container");
let lh = gc_formats::level_wad::LevelHeader::parse(&raw).expect("level header");
let data = lh.data;
let Some(offset) = data.byte_offset() else {
continue;
};
let len = data.byte_len() as usize;
let extent = &raw[offset as usize..offset as usize + len];
let dh = gc_formats::level_data::LevelDataHeader::parse(extent)
.unwrap_or_else(|e| panic!("{}: data extent header: {e}", entry.name));
for (part, r) in dh.present_parts() {
assert!(
r.end() <= extent.len() as u64,
"{}: {part:?} ends at {} but the extent is {} bytes",
entry.name,
r.end(),
extent.len()
);
}
// The geometry is the big one and must be substantial.
assert!(
dh.core_data.size > 1_000_000,
"{}: core_data is only {} bytes",
entry.name,
dh.core_data.size
);
checked += 1;
}
assert_eq!(checked, 27, "expected 27 level containers");
}
/// The geometry must decompress. This is the first test that touches real level
/// content rather than headers.
#[test]
fn level_geometry_decompresses() {
let path = require_disc!();
let iso = gc_formats::iso9660::IsoImage::open(&path).expect("ISO should open");
let entry = iso.find("G/LEVEL0.WAD").expect("level 0");
let raw = gc_formats::iso9660::read_at(&path, entry.lba, entry.size).expect("read container");
let lh = gc_formats::level_wad::LevelHeader::parse(&raw).expect("level header");
let data = lh.data;
let extent = &raw[data.byte_offset().unwrap() as usize
..(data.byte_offset().unwrap() + data.byte_len()) as usize];
let dh = gc_formats::level_data::LevelDataHeader::parse(extent).expect("data header");
let core = dh
.core_data
.slice(extent, extent.len())
.expect("core_data slice");
assert!(
gc_formats::wad::is_wad(core),
"core_data should start with the WAD magic"
);
let decoded = gc_formats::wad::decompress(core).expect("core_data should decompress");
assert!(
decoded.len() > core.len(),
"decompressed geometry ({}) should exceed the compressed size ({})",
decoded.len(),
core.len()
);
}
/// The terrain itself. This is the first test to touch real level content: it
/// parses the tfrags directory and decodes vertex positions from every patch.
///
/// The gate is deliberately about *coverage*, not correctness of a sample: a
/// parser that works on one tfrag and silently returns `None` on the rest would
/// otherwise pass.
#[test]
fn tfrag_vertices_decode_for_every_level() {
require_disc!();
// Opening the image also confirms the disc is readable, not merely present.
gc_formats::iso9660::IsoImage::open(std::path::Path::new(
&std::env::var("GC_DISC").expect("GC_DISC is set by require_disc!"),
))
.expect("ISO should open");
// Where the unpacked data lives. GC_EXTRACTED overrides; otherwise the
// default location used during development.
let data = std::env::var_os("GC_EXTRACTED")
.map(PathBuf::from)
.unwrap_or_else(|| {
let home = std::env::var("HOME").unwrap_or_else(|_| ".".to_string());
PathBuf::from(home).join("Documents/gc-extracted")
});
if !data.exists() {
eprintln!(
"skipped: unpack the disc first, e.g.\
gc-extract unpack <disc.iso> ~/Documents/gc-extracted\
or point GC_EXTRACTED at an existing unpack"
);
return;
}
let mut levels = 0usize;
let mut total_verts = 0usize;
let mut total_tfrags = 0usize;
for n in 0..27 {
let dir = data.join(format!("level{n}"));
let core_path = dir.join("core_data.bin");
let index_path = dir.join("core_index.bin");
if !core_path.exists() || !index_path.exists() {
continue;
}
let core = std::fs::read(&core_path).expect("core_data");
let index = std::fs::read(&index_path).expect("core_index");
// The tfrags block starts at the core header's 0x08 field and runs to
// the next region that exists.
let region_start =
|off: usize| -> i32 { i32::from_le_bytes(index[off..off + 4].try_into().unwrap()) };
let start = region_start(0x08) as usize;
let end = [0x0c_usize, 0x10, 0x14]
.iter()
.map(|&o| region_start(o))
.filter(|&v| v > 0)
.min()
.unwrap_or(core.len() as i32) as usize;
let block = &core[start..end];
let header = gc_formats::tfrag::TfragsBlock::parse(block).expect("tfrags block header");
assert_eq!(header.table_offset, 0x40, "level{n}: table offset");
let table_offset = header.table_offset as usize;
let mut decoded = 0usize;
let mut verts = 0usize;
for i in 0..header.tfrag_count as usize {
let th = header.header(block, i).expect("tfrag header");
let data_base = table_offset.wrapping_add(th.data as usize);
if data_base >= block.len() {
continue;
}
let slice = &block[data_base..];
if let Some(p) = gc_formats::tfrag::tfrag_positions(slice, &th) {
decoded += 1;
verts += p.len();
assert_eq!(p.len(), th.vert_count as usize);
}
}
assert!(header.tfrag_count > 0, "level{n}: no tfrags");
assert_eq!(
decoded, header.tfrag_count as usize,
"level{n}: only {decoded} of {} tfrags decoded",
header.tfrag_count
);
levels += 1;
total_tfrags += header.tfrag_count as usize;
total_verts += verts;
}
assert!(levels > 0, "no unpacked levels were found");
assert!(
total_tfrags > 5000,
"expected thousands of tfrags, got {total_tfrags}"
);
assert!(
total_verts > 100_000,
"expected 100k+ vertices, got {total_verts}"
);
eprintln!("decoded {total_verts} vertices from {total_tfrags} tfrags across {levels} levels");
}
/// Terrain topology: strips and index arrays must expand to exactly the
/// triangle count each patch's header claims.
///
/// `tri_count` is stored in the patch header but is not derivable from the
/// lists directly, so reproducing it on all 18,102 patches is a strong check
/// that the strip walk, the index bank and the LOD assignment are all right.
/// Triangle indices must also stay inside the vertex-info range for the LOD.
#[test]
fn tfrag_topology_reproduces_the_header_triangle_count() {
require_disc!();
gc_formats::iso9660::IsoImage::open(std::path::Path::new(
&std::env::var("GC_DISC").expect("GC_DISC is set by require_disc!"),
))
.expect("ISO should open");
let data = std::env::var_os("GC_EXTRACTED")
.map(PathBuf::from)
.unwrap_or_else(|| {
let home = std::env::var("HOME").unwrap_or_else(|_| ".".to_string());
PathBuf::from(home).join("Documents/gc-extracted")
});
if !data.exists() {
eprintln!("skipped: unpack the disc first");
return;
}
let mut patches = 0usize;
let mut triangles = 0usize;
let mut levels = 0usize;
for n in 0..27 {
let dir = data.join(format!("level{n}"));
let core = match std::fs::read(dir.join("core_data.bin")) {
Ok(c) => c,
Err(_) => continue,
};
let index = match std::fs::read(dir.join("core_index.bin")) {
Ok(i) => i,
Err(_) => continue,
};
let region =
|off: usize| i32::from_le_bytes(index[off..off + 4].try_into().unwrap()) as usize;
let start = region(0x08);
let end = [0x0c_usize, 0x10, 0x14]
.iter()
.map(|&o| region(o))
.filter(|&v| v > 0)
.min()
.unwrap_or(core.len());
let block = &core[start..end];
let header = gc_formats::tfrag::TfragsBlock::parse(block).expect("tfrags block header");
let table = header.table_offset as usize;
for i in 0..header.tfrag_count as usize {
let th = header.header(block, i).expect("tfrag header");
let data_base = table.wrapping_add(th.data as usize);
if data_base >= block.len() {
continue;
}
let g = gc_formats::tfrag::parse_tfrag(&block[data_base..], &th)
.unwrap_or_else(|e| panic!("level{n} patch {i}: {e}"));
let tris = gc_formats::tfrag::tfrag_triangles(&g, 0)
.unwrap_or_else(|e| panic!("level{n} patch {i}: {e}"));
assert_eq!(
tris.len(),
th.tri_count as usize,
"level{n} patch {i}: {} triangles, header says {}",
tris.len(),
th.tri_count
);
let vinfo = g.lod_vinfo_count(0);
for t in &tris {
let idx = [t.a as usize, t.b as usize, t.c as usize];
assert!(
idx.iter().all(|&v| v < vinfo),
"level{n} patch {i}: triangle index outside {vinfo} vertex-info entries"
);
assert!((t.ad_gif as usize) < g.ad_gifs.len());
}
patches += 1;
triangles += tris.len();
}
levels += 1;
}
assert!(levels > 0, "no unpacked levels were found");
assert!(patches > 18_000, "expected 18k+ patches, got {patches}");
assert!(
triangles > 700_000,
"expected 700k+ triangles, got {triangles}"
);
eprintln!("reproduced {triangles} triangles across {patches} patches in {levels} levels");
}
/// Texture bindings: every ad-gif a patch uses must index an entry that
/// actually exists in the level's texture table, and the light array must be
/// one record per vertex.
///
/// The texture table is the join between tfrags and the texel data, so an
/// out-of-range index here means the level's geometry and its textures have
/// been misread independently of each other.
#[test]
fn tfrag_ad_gifs_index_the_level_texture_table() {
require_disc!();
gc_formats::iso9660::IsoImage::open(std::path::Path::new(
&std::env::var("GC_DISC").expect("GC_DISC is set by require_disc!"),
))
.expect("ISO should open");
let data = std::env::var_os("GC_EXTRACTED")
.map(PathBuf::from)
.unwrap_or_else(|| {
let home = std::env::var("HOME").unwrap_or_else(|_| ".".to_string());
PathBuf::from(home).join("Documents/gc-extracted")
});
if !data.exists() {
eprintln!("skipped: unpack the disc first");
return;
}
let mut patches = 0usize;
let mut ad_gifs = 0usize;
let mut textures_seen = 0usize;
let mut textures_total = 0usize;
let mut levels = 0usize;
for n in 0..27 {
let dir = data.join(format!("level{n}"));
let core = match std::fs::read(dir.join("core_data.bin")) {
Ok(c) => c,
Err(_) => continue,
};
let index = match std::fs::read(dir.join("core_index.bin")) {
Ok(i) => i,
Err(_) => continue,
};
let ch = gc_formats::level_core::LevelCoreHeader::parse(&index).expect("core header");
let textures = gc_formats::level_core::texture_table(&index, ch.tfrag_textures)
.expect("texture table");
assert!(!textures.is_empty(), "level{n}: no tfrag textures");
// Indices are per-level, so the pair is what identifies a texture.
let mut level_seen = std::collections::BTreeSet::new();
let region =
|off: usize| i32::from_le_bytes(index[off..off + 4].try_into().unwrap()) as usize;
let start = region(0x08);
let end = [0x0c_usize, 0x10, 0x14]
.iter()
.map(|&o| region(o))
.filter(|&v| v > 0)
.min()
.unwrap_or(core.len());
let block = &core[start..end];
let header = gc_formats::tfrag::TfragsBlock::parse(block).expect("tfrags block header");
let table = header.table_offset as usize;
for i in 0..header.tfrag_count as usize {
let th = header.header(block, i).expect("tfrag header");
let data_base = table.wrapping_add(th.data as usize);
if data_base >= block.len() {
continue;
}
let g = gc_formats::tfrag::parse_tfrag(&block[data_base..], &th)
.unwrap_or_else(|e| panic!("level{n} patch {i}: {e}"));
assert_eq!(
g.lights.len(),
th.vert_count as usize,
"level{n} patch {i}: {} light records for {} vertices",
g.lights.len(),
th.vert_count
);
assert_eq!(
g.rgba.len(),
th.rgba_size as usize * 4,
"level{n} patch {i}: rgba"
);
for a in &g.ad_gifs {
let t = a.texture_index();
assert!(
t < textures.len(),
"level{n} patch {i}: texture {} outside the {} entry table",
t,
textures.len()
);
let tex = &textures[t];
assert!(
tex.width > 0 && tex.height > 0 && tex.width <= 256 && tex.height <= 256,
"level{n} patch {i}: texture {t} is {}x{}",
tex.width,
tex.height
);
level_seen.insert(t);
ad_gifs += 1;
}
patches += 1;
}
textures_seen += level_seen.len();
textures_total += textures.len();
levels += 1;
}
assert!(levels > 0, "no unpacked levels were found");
assert!(patches > 18_000, "expected 18k+ patches, got {patches}");
// Most of each level's texture table should be referenced by some tfrag. A
// handful genuinely go unused; if that share grows, the ad-gif walk has
// started missing primitives rather than the data having spare entries.
let covered = textures_seen as f64 / textures_total as f64;
assert!(
covered > 0.85,
"only {textures_seen} of {textures_total} level textures referenced ({:.1}%)",
covered * 100.0
);
eprintln!(
"{ad_gifs} ad-gifs over {patches} patches reference {textures_seen}/{textures_total} level textures"
);
}
/// Level textures decode: every tfrag texture's base level must resolve to a
/// plausible RGBA image.
///
/// This is the join between the texture table, the texel block and GS RAM, so
/// it is where a wrong CLUT remap, a wrong alpha scale or a wrong pixel base
/// would show up. The check is deliberately about *shape*, not specific
/// colours: a decoded image is plausible when it is fully opaque, is not
/// uniformly one colour, and uses more than a handful of distinct entries.
#[test]
fn tfrag_textures_decode_to_plausible_images() {
require_disc!();
gc_formats::iso9660::IsoImage::open(std::path::Path::new(
&std::env::var("GC_DISC").expect("GC_DISC is set by require_disc!"),
))
.expect("ISO should open");
let data = std::env::var_os("GC_EXTRACTED")
.map(PathBuf::from)
.unwrap_or_else(|| {
let home = std::env::var("HOME").unwrap_or_else(|_| ".".to_string());
PathBuf::from(home).join("Documents/gc-extracted")
});
if !data.exists() {
eprintln!("skipped: unpack the disc first");
return;
}
let mut decoded = 0usize;
let mut opaque = 0usize;
let mut multi_colour = 0usize;
let mut flat = 0usize;
for n in 0..27 {
let dir = data.join(format!("level{n}"));
let core = match std::fs::read(dir.join("core_data.bin")) {
Ok(c) => c,
Err(_) => continue,
};
let index = match std::fs::read(dir.join("core_index.bin")) {
Ok(i) => i,
Err(_) => continue,
};
let gs = match std::fs::read(dir.join("gs_ram.bin")) {
Ok(g) => g,
Err(_) => {
eprintln!("level{n}: no gs_ram.bin, skipping");
continue;
}
};
let ch = gc_formats::level_core::LevelCoreHeader::parse(&index).expect("core header");
let textures_at = ch.textures_base.max(0) as usize;
let texture_block = &core[textures_at..];
let table =
gc_formats::level_core::texture_table(&index, ch.tfrag_textures).expect("table");
for (i, e) in table.iter().enumerate() {
let img = gc_formats::texture::base_image(texture_block, &gs, e)
.unwrap_or_else(|err| panic!("level{n} texture {i}: {err}"));
let t = img.decode().unwrap();
let texels = (e.width as i32) * (e.height as i32);
assert_eq!(t.rgba.len(), (texels * 4) as usize);
assert_eq!(t.width, e.width as u32);
decoded += 1;
// Count distinct colours and how many texels are fully opaque.
let mut seen = std::collections::HashSet::new();
let mut op = 0usize;
for px in t.rgba.chunks_exact(4) {
seen.insert([px[0], px[1], px[2], px[3]]);
if px[3] == 0xff {
op += 1;
}
}
if seen.len() > 8 {
multi_colour += 1;
} else {
flat += 1;
}
if op == texels as usize {
opaque += 1;
}
}
}
assert!(decoded > 1_500, "only {decoded} textures decoded");
// Level art is mostly opaque and has real detail. A flat, transparent or
// single-colour result almost always means a CLUT or offset mistake.
let opaque_pct = opaque as f64 / decoded as f64;
let detail_pct = multi_colour as f64 / decoded as f64;
assert!(
opaque_pct > 0.9,
"only {opaque:.1}% of textures are fully opaque"
);
assert!(
detail_pct > 0.9,
"only {detail_pct:.1} of textures have >8 colours"
);
eprintln!(
"{decoded} textures decoded: {:.1}% fully opaque, {:.1}% with >8 colours ({flat} flat)",
opaque_pct * 100.0,
detail_pct * 100.0
);
}
/// LOD linkage: every LOD-01 and LOD-0 vertex-info entry must resolve to a
/// first parent that exists and to positions inside the patch.
///
/// The parent-index arrays are V4_8 unpacks separated from the strips and the
/// strip indices only by their VU address, so a misclassification here is
/// silent: the arrays still parse, they just hold the wrong numbers. Resolving
/// every entry is what catches it.
#[test]
fn tfrag_lod_parents_resolve_for_every_entry() {
require_disc!();
gc_formats::iso9660::IsoImage::open(std::path::Path::new(
&std::env::var("GC_DISC").expect("GC_DISC is set by require_disc!"),
))
.expect("ISO should open");
let data = std::env::var_os("GC_EXTRACTED")
.map(PathBuf::from)
.unwrap_or_else(|| {
let home = std::env::var("HOME").unwrap_or_else(|_| ".".to_string());
PathBuf::from(home).join("Documents/gc-extracted")
});
if !data.exists() {
eprintln!("skipped: unpack the disc first");
return;
}
let mut patches = 0usize;
let mut entries = 0usize;
let mut lod01 = 0usize;
let mut lod0 = 0usize;
let mut resolved_common = 0usize;
let mut common_total = 0usize;
let mut primary_failed = 0usize;
let mut extras_unresolved = 0usize;
for n in 0..27 {
let dir = data.join(format!("level{n}"));
let core = match std::fs::read(dir.join("core_data.bin")) {
Ok(c) => c,
Err(_) => continue,
};
let index = match std::fs::read(dir.join("core_index.bin")) {
Ok(i) => i,
Err(_) => continue,
};
let region =
|off: usize| i32::from_le_bytes(index[off..off + 4].try_into().unwrap()) as usize;
let start = region(0x08);
let end = [0x0c_usize, 0x10, 0x14]
.iter()
.map(|&o| region(o))
.filter(|&v| v > 0)
.min()
.unwrap_or(core.len());
let block = &core[start..end];
let header = gc_formats::tfrag::TfragsBlock::parse(block).expect("tfrags block");
let table = header.table_offset as usize;
for i in 0..header.tfrag_count as usize {
let th = header.header(block, i).expect("tfrag header");
let data_base = table.wrapping_add(th.data as usize);
if data_base >= block.len() {
continue;
}
let g = gc_formats::tfrag::parse_tfrag(&block[data_base..], &th)
.unwrap_or_else(|e| panic!("level{n} patch {i}: {e}"));
common_total += g.vinfo_tier[0];
if n == 0 && patches < 5 {
eprintln!(
"p{i}: tier={:?} n01={} n0={} p01={}b x01={}b p0={}b x0={}b",
g.vinfo_tier,
g.vu_positions_lod_01_count,
g.vu_positions_lod_0_count,
g.parent_indices_lod01.len(),
g.unk_indices_2_lod01.len(),
g.parent_indices_lod0.len(),
g.unk_indices_2_lod0.len()
);
}
for v in 0..g.vertex_info.len() {
entries += 1;
match gc_formats::tfrag::tfrag_lod_link(&g, v) {
Some(link) => {
if v < g.vinfo_tier[0] {
resolved_common += 1;
}
// Parents must index real vertex info and real positions.
assert!(
link.parent1_vinfo < g.vertex_info.len(),
"level{n} patch {i}: entry {v} parent {} outside {} entries",
link.parent1_vinfo,
g.vertex_info.len()
);
assert!(link.own_position < g.positions.len());
assert!(link.parent1_position < g.positions.len());
assert!(link.parent2_position < g.positions.len());
// The first parent of a LOD-01 entry is always a common one.
if link.tier == gc_formats::tfrag::TfragMorphTier::Lod01 {
assert!(
link.parent1_vinfo < g.vinfo_tier[0],
"level{n} patch {i}: LOD-01 entry {v} parent {} is not a common entry",
link.parent1_vinfo
);
lod01 += 1;
} else {
lod0 += 1;
}
}
None => {
// Distinguish the two kinds of LOD entry. A *primary*
// entry has a real position and a recorded parent and
// must always resolve; an *extra* entry is a
// non-position bookkeeping record whose array address
// can collide with the strip index array.
let c = g.vinfo_tier[0];
let kind = if v < c {
None
} else if v < c + g.vinfo_tier[1] {
Some((g.vu_positions_lod_01_count, v - c, true))
} else {
Some((g.vu_positions_lod_0_count, v - c - g.vinfo_tier[1], false))
};
match kind {
None => {}
Some((prim, k, _)) if k < prim => primary_failed += 1,
Some(_) => extras_unresolved += 1,
}
}
}
}
patches += 1;
}
}
assert!(patches > 18_000, "expected 18k+ patches, got {patches}");
// A common entry never has a link: they are the full-detail positions and
// have no parent. Anything else means the tier boundaries are wrong.
assert!(
resolved_common == 0,
"{resolved_common} common entries claimed an LOD parent"
);
assert!(
lod01 > 0 && lod0 > 0,
"both LOD tiers should occur in the data"
);
assert_eq!(
primary_failed, 0,
"{primary_failed} primary LOD entries did not resolve"
);
assert_eq!(
extras_unresolved, 0,
"{extras_unresolved} extra LOD entries did not resolve"
);
// Common entries have no link; every other entry does.
assert_eq!(entries, common_total + lod01 + lod0);
eprintln!(
"{entries} vertex-info entries over {patches} patches: {common_total} common, \
{lod01} LOD-01 and {lod0} LOD-0, all resolved"
);
}
/// The level core index's class tables.
///
/// These are what put the environment on top of the terrain: tie instances,
/// moby actors and shrub foliage. They were ruled out earlier for want of an
/// entry size, which turned out to be knowable exactly.
///
/// The check is the chain: each table must end precisely where the next one
/// begins, moby (32 bytes/entry) into tie (32) into shrub (48) into the tfrag
/// texture table. That closes on all 27 levels and would not close if any
/// entry size were wrong, so it is the evidence rather than a coincidence.
#[test]
fn level_core_class_tables_tile_the_index() {
require_disc!();
gc_formats::iso9660::IsoImage::open(std::path::Path::new(
&std::env::var("GC_DISC").expect("GC_DISC is set by require_disc!"),
))
.expect("ISO should open");
let data = std::env::var_os("GC_EXTRACTED")
.map(PathBuf::from)
.unwrap_or_else(|| {
let home = std::env::var("HOME").unwrap_or_else(|_| ".".to_string());
PathBuf::from(home).join("Documents/gc-extracted")
});
if !data.exists() {
eprintln!("skipped: unpack the disc first");
return;
}
use gc_formats::level_core as lc;
let mut levels = 0usize;
let (mut moby, mut tie, mut shrub, mut textures) = (0usize, 0usize, 0usize, 0usize);
for n in 0..27 {
let dir = data.join(format!("level{n}"));
let Ok(index) = std::fs::read(dir.join("core_index.bin")) else {
continue;
};
let h = lc::LevelCoreHeader::parse(&index).expect("core header");
let end = |r: lc::ArrayRange, size: usize| r.offset as usize + r.count as usize * size;
assert_eq!(
end(h.moby_classes, lc::MOBY_CLASS_SIZE),
h.tie_classes.offset as usize,
"level{n}: moby -> tie"
);
assert_eq!(
end(h.tie_classes, lc::TIE_CLASS_SIZE),
h.shrub_classes.offset as usize,
"level{n}: tie -> shrub"
);
assert_eq!(
end(h.shrub_classes, lc::SHRUB_CLASS_SIZE),
h.tfrag_textures.offset as usize,
"level{n}: shrub -> textures"
);
// Every entry parses, and its asset offset lands inside the level.
if n == 0 {
eprintln!(
"hdr moby={:?} tie={:?} shrub={:?} tex={:?} base={}",
h.moby_classes, h.tie_classes, h.shrub_classes, h.tfrag_textures, h.textures_base
);
eprintln!("index[192..200] = {:?}", &index[192..200]);
}
let moby_v = lc::class_table(
&index,
h.moby_classes,
lc::MOBY_CLASS_SIZE,
lc::ClassEntry::parse,
)
.expect("moby classes");
let tie_v = lc::class_table(
&index,
h.tie_classes,
lc::TIE_CLASS_SIZE,
lc::ClassEntry::parse,
)
.expect("tie classes");
let shrub_v = lc::class_table(
&index,
h.shrub_classes,
lc::SHRUB_CLASS_SIZE,
lc::ShrubClassEntry::parse,
)
.expect("shrub classes");
let tex_v = lc::texture_table(&index, h.tfrag_textures).expect("tfrag textures");
assert_eq!(moby_v.len(), h.moby_classes.count as usize);
for (i, c) in moby_v.iter().chain(tie_v.iter()).enumerate() {
assert!(
c.offset_in_asset_wad >= 0,
"level{n} entry {i}: asset offset {}",
c.offset_in_asset_wad
);
}
// Billboard slots are optional: every shrub class on level 0 carries
// them all zero, so only their sign is meaningful here.
for s in &shrub_v {
assert!(s.base.offset_in_asset_wad >= 0);
assert!(
s.palette_offset >= -1 && s.texture_offset >= -1,
"level{n}: shrub billboard offsets below the -1 sentinel"
);
}
moby += moby_v.len();
tie += tie_v.len();
shrub += shrub_v.len();
textures += tex_v.len();
levels += 1;
}
assert_eq!(levels, 27, "expected all 27 levels, got {levels}");
assert!(
moby + tie + shrub > 1000,
"only {moby}+{tie}+{shrub} class entries"
);
eprintln!(
"level core index: {moby} moby, {tie} tie, {shrub} shrub classes, \
{textures} tfrag textures across {levels} levels"
);
}
/// The moby, tie and shrub class tables point into `core_data`, and they do so
/// without overlapping.
///
/// `assets_decompressed_size` is the size of `core_data` itself, so there is
/// no separate asset container: the class entries index the decompressed asset
/// lump directly. If that is right, every offset must land inside the lump, the
/// three tables must occupy disjoint spans, and each must be internally sorted
/// so the geometry is laid out in class order.
#[test]
fn class_geometry_offsets_tile_core_data_without_overlap() {
require_disc!();
gc_formats::iso9660::IsoImage::open(std::path::Path::new(
&std::env::var("GC_DISC").expect("GC_DISC is set by require_disc!"),
))
.expect("ISO should open");
let data = std::env::var_os("GC_EXTRACTED")
.map(PathBuf::from)
.unwrap_or_else(|| {
let home = std::env::var("HOME").unwrap_or_else(|_| ".".to_string());
PathBuf::from(home).join("Documents/gc-extracted")
});
if !data.exists() {
eprintln!("skipped: unpack the disc first");
return;
}
use gc_formats::level_core as lc;
let mut levels = 0usize;
for n in 0..27 {
let dir = data.join(format!("level{n}"));
let (Ok(index), Ok(core)) = (
std::fs::read(dir.join("core_index.bin")),
std::fs::read(dir.join("core_data.bin")),
) else {
continue;
};
let h = lc::LevelCoreHeader::parse(&index).expect("core header");
// The claim under test: the "asset lump" is core_data itself.
assert_eq!(
h.assets_decompressed_size as usize,
core.len(),
"level{n}: assets_decompressed_size is not core_data's length"
);
let span = |r: lc::ArrayRange, size: usize| -> Vec<usize> {
lc::class_table(&index, r, size, lc::ClassEntry::parse)
.unwrap_or_default()
.iter()
.map(|c| c.offset_in_asset_wad as usize)
.collect()
};
// Shrub entries are read as ShrubClassEntry so the offsets line up.
let shrub: Vec<usize> = lc::class_table(
&index,
h.shrub_classes,
lc::SHRUB_CLASS_SIZE,
lc::ShrubClassEntry::parse,
)
.unwrap_or_default()
.iter()
.map(|s| s.base.offset_in_asset_wad as usize)
.collect();
let moby = span(h.moby_classes, lc::MOBY_CLASS_SIZE);
let tie = span(h.tie_classes, lc::TIE_CLASS_SIZE);
// An offset of 0 marks a slot with no geometry rather than the start of
// the lump, so those are excluded from the span checks. Entries are not
// sorted by class number and the offsets are not monotonic, so nothing
// here assumes an order.
let moby_l: Vec<usize> = moby.iter().copied().filter(|&o| o != 0).collect();
let tie_l: Vec<usize> = tie.iter().copied().filter(|&o| o != 0).collect();
let shrub_l: Vec<usize> = shrub.iter().copied().filter(|&o| o != 0).collect();
for (name, v) in [("moby", &moby), ("tie", &tie), ("shrub", &shrub)] {
for &o in v {
assert!(
o < core.len(),
"level{n}: {name} offset {o} past core data ({})",
core.len()
);
}
}
// The three spans must not overlap each other.
for (an, a) in [("moby", &moby_l), ("tie", &tie_l), ("shrub", &shrub_l)] {
for (bn, b) in [("moby", &moby_l), ("tie", &tie_l), ("shrub", &shrub_l)] {
// A level may have no geometry of one kind at all.
if an >= bn || a.is_empty() || b.is_empty() {
continue;
}
let (lo, hi) = (a[0], *a.last().unwrap());
for &o in b {
assert!(
o >= hi || o < lo,
"level{n}: {an} [{lo},{hi}] overlaps {bn} at {o}"
);
}
}
}
levels += 1;
}
assert_eq!(levels, 27, "expected all 27 levels, got {levels}");
eprintln!("class geometry offsets verified inside core_data on {levels} levels");
}
/// Tie class headers, as far as RAC1 and RAC2 agree.
///
/// The check that carries the weight is `o_class`: the class's own number at
/// header offset 0x44 equals the number the core index filed it under, on every
/// class of every level. That is what makes the header base trustworthy rather
/// than merely plausible.
#[test]
fn tie_class_headers_match_their_index_entry() {
require_disc!();
gc_formats::iso9660::IsoImage::open(std::path::Path::new(
&std::env::var("GC_DISC").expect("GC_DISC is set by require_disc!"),
))
.expect("ISO should open");
let data = std::env::var_os("GC_EXTRACTED")
.map(PathBuf::from)
.unwrap_or_else(|| {
let home = std::env::var("HOME").unwrap_or_else(|_| ".".to_string());
PathBuf::from(home).join("Documents/gc-extracted")
});
if !data.exists() {
eprintln!("skipped: unpack the disc first");
return;
}
use gc_formats::level_core as lc;
use gc_formats::tie::{TieClassHeader, TIE_CLASS_HEADER_MATCHED};
let mut levels = 0usize;
let (mut classes, mut ordered, mut unordered) = (0usize, 0usize, 0usize);
for n in 0..27 {
let dir = data.join(format!("level{n}"));
let (Ok(index), Ok(core)) = (
std::fs::read(dir.join("core_index.bin")),
std::fs::read(dir.join("core_data.bin")),
) else {
continue;
};
let h = lc::LevelCoreHeader::parse(&index).expect("core header");
let entries = lc::class_table(
&index,
h.tie_classes,
lc::TIE_CLASS_SIZE,
lc::ClassEntry::parse,
)
.expect("tie classes");
for e in &entries {
let off = e.offset_in_asset_wad as usize;
if off == 0 {
continue; // slot with no geometry
}
let at = off + TIE_CLASS_HEADER_MATCHED;
assert!(at <= core.len(), "level{n}: tie class past core data");
let t = TieClassHeader::parse(&core[off..at])
.unwrap_or_else(|err| panic!("level{n}: tie class {} header: {err}", e.o_class));
assert_eq!(t.o_class, e.o_class, "level{n}: tie o_class mismatch");
assert!(
t.far_dist > 0.0,
"level{n}: tie far distance {}",
t.far_dist
);
if 0.0 < t.near_dist && t.near_dist < t.mid_dist && t.mid_dist < t.far_dist {
ordered += 1;
} else {
unordered += 1;
}
classes += 1;
}
levels += 1;
}
assert_eq!(levels, 27, "expected all 27 levels, got {levels}");
assert!(classes > 1_500, "only {classes} tie classes");
// Ordered distances are the expected shape; the exceptions are real and
// unexplained, so they are reported rather than asserted away.
assert!(
ordered * 20 >= classes * 19,
"only {ordered} of {classes} tie classes have ordered LOD distances"
);
eprintln!(
"tie: {classes} class headers, o_class matches the index on all; \\
{ordered} have ordered LOD distances, {unordered} do not"
);
}
/// The occlusion PVS grid.
///
/// The check that makes this real is the mask array: it starts at
/// `masks_offset` and runs to `(highest_mask + 1) * 0x80`, and on every level
/// that ends within a few bytes of the block's own length. A wrong tree shape
/// or a wrong cell size would leave the highest mask index somewhere else
/// entirely and the array would not fit.
#[test]
fn occlusion_grids_parse_on_every_level() {
require_disc!();
gc_formats::iso9660::IsoImage::open(std::path::Path::new(
&std::env::var("GC_DISC").expect("GC_DISC is set by require_disc!"),
))
.expect("ISO should open");
let data = std::env::var_os("GC_EXTRACTED")
.map(PathBuf::from)
.unwrap_or_else(|| {
let home = std::env::var("HOME").unwrap_or_else(|_| ".".to_string());
PathBuf::from(home).join("Documents/gc-extracted")
});
if !data.exists() {
eprintln!("skipped: unpack the disc first");
return;
}
use gc_formats::level_core::LevelCoreHeader;
use gc_formats::occlusion::parse_occlusion_block;
let mut levels = 0usize;
let mut absent = 0usize;
let mut widest_slack = 0usize;
let (mut cells, mut masks) = (0usize, 0usize);
for n in 0..27 {
let dir = data.join(format!("level{n}"));
let (Ok(core), Ok(index)) = (
std::fs::read(dir.join("core_data.bin")),
std::fs::read(dir.join("core_index.bin")),
) else {
continue;
};
let h = LevelCoreHeader::parse(&index).expect("core header");
// An offset of 0 means the level has no occlusion data at all, which is
// not the same as "at the start of the file" -- that is where the
// tfrags block lives, and parsing it as a grid produces a mask array
// that fits anyway, which is how this nearly went wrong.
if h.occlusion <= 0 {
absent += 1;
continue;
}
let start = h.occlusion as usize;
// The block runs to the sky region, or to the end when there is none.
let end = if h.sky > 0 {
h.sky as usize
} else {
core.len()
};
assert!(
start < end && end <= core.len(),
"level{n}: bad occlusion range"
);
let block = &core[start..end];
let o = parse_occlusion_block(block)
.unwrap_or_else(|e| panic!("level{n}: occlusion block: {e}"));
// Every mask a cell names exists.
for c in &o.cells {
assert!(
(c.mask as usize) < o.masks.len(),
"level{n}: cell names a missing mask"
);
}
// The array ends at or just before the block's end. Retail levels sit
// within a few bytes; a gross error would leave a large gap.
let need = o.masks_offset as usize + o.masks.len() * gc_formats::occlusion::MASK_BYTES;
assert!(need <= block.len(), "level{n}: masks run past the block");
let slack = block.len() - need;
// Levels whose grid is empty are mostly header and padding, so this is
// proportional and only applies where there are cells at all.
if !o.cells.is_empty() {
assert!(
slack * 8 < block.len(),
"level{n}: {slack} of {} bytes unexplained after the mask array",
block.len()
);
}
widest_slack = widest_slack.max(slack);
cells += o.cells.len();
masks += o.masks.len();
levels += 1;
}
assert_eq!(
levels + absent,
27,
"expected all 27 levels, got {}",
levels + absent
);
assert_eq!(
absent, 3,
"expected 3 levels without occlusion data, got {absent}"
);
assert!(cells > 400_000, "only {cells} occlusion cells");
eprintln!(
"occlusion: {cells} populated cells over {masks} masks across {levels} levels; \
widest unexplained tail {widest_slack} bytes"
);
}
/// The sound extent framing.
///
/// The invariant here is `sblk_offset + sblk_size == daw_offset`, which holds
/// on all 27 levels and pins the meaning of the four head fields. `DAW` never
/// reaches the end of the file; the tail is positive on every level, so the
/// size field is not the whole region and this test asserts the direction
/// rather than a size.
#[test]
fn sound_bank_framing_holds_on_every_level() {
require_disc!();
let data = std::env::var_os("GC_EXTRACTED")
.map(PathBuf::from)
.unwrap_or_else(|| {
let home = std::env::var("HOME").unwrap_or_else(|_| ".".to_string());
PathBuf::from(home).join("Documents/gc-extracted")
});
if !data.exists() {
eprintln!("skipped: unpack the disc first");
return;
}
use gc_formats::sound_bank::parse_sound_bank;
let mut levels = 0usize;
let mut sblk_bytes = 0usize;
let mut daw_bytes = 0usize;
let (mut narrowest, mut widest) = (usize::MAX, 0usize);
for n in 0..27 {
let raw = match std::fs::read(data.join(format!("level{n}")).join("sound_bank.bin")) {
Ok(v) => v,
Err(_) => continue,
};
let s = parse_sound_bank(&raw).unwrap_or_else(|e| panic!("level{n}: sound bank: {e}"));
assert_eq!(s.header.version, 3, "level{n}: sound bank version");
assert_eq!(s.header.unknown_4, 2, "level{n}: sound bank unknown_4");
assert_eq!(
s.header.sblk_offset, 24,
"level{n}: SBlk sits at 24 on every level"
);
assert!(
s.header.sblk_offset + s.header.sblk_size == s.header.daw_offset,
"level{n}: SBlk must run into DAW with no gap"
);
assert!(s.has_sblk_magic(), "level{n}: SBlk magic");
assert!(s.has_daw_tag(), "level{n}: DAW tag at SBlk+12");
assert_eq!(s.sblk_version(), Some(1), "level{n}: SBlk version");
// The tail is always in the same direction: the extent is longer than
// the DAW region it describes.
narrowest = narrowest.min(s.daw_tail);
widest = widest.max(s.daw_tail);
sblk_bytes += s.sblk.len();
daw_bytes += s.daw.len();
levels += 1;
}
assert_eq!(levels, 27, "expected all 27 levels, got {levels}");
assert!(sblk_bytes > 300_000, "only {sblk_bytes} SBlk bytes");
assert!(daw_bytes > 20_000_000, "only {daw_bytes} DAW bytes");
eprintln!(
"sound_bank: {sblk_bytes} SBlk + {daw_bytes} DAW bytes across {levels} levels; \
unexplained tail {narrowest}..{widest} bytes"
);
}
/// Collision container framing.
///
/// The invariant is the header's own self-description: `header_size` is 0x40
/// on every level, and `header_size + payload_size` stays inside `core_data`.
/// The payload is deliberately left undecoded -- see `collision.rs`.
#[test]
fn collision_framing_holds_on_every_level() {
require_disc!();
let data = std::env::var_os("GC_EXTRACTED")
.map(PathBuf::from)
.unwrap_or_else(|| {
let home = std::env::var("HOME").unwrap_or_else(|_| ".".to_string());
PathBuf::from(home).join("Documents/gc-extracted")
});
if !data.exists() {
eprintln!("skipped: unpack the disc first");
return;
}
use gc_formats::collision::{CollisionHeader, COLLISION_HEADER_SIZE};
use gc_formats::level_core::LevelCoreHeader;
let mut levels = 0usize;
let mut empty = 0usize;
let mut payload_bytes = 0usize;
for n in 0..27 {
let dir = data.join(format!("level{n}"));
let (Ok(core), Ok(index)) = (
std::fs::read(dir.join("core_data.bin")),
std::fs::read(dir.join("core_index.bin")),
) else {
continue;
};
let h = LevelCoreHeader::parse(&index).expect("core header");
let region = CollisionHeader::region(&core, h.collision)
.unwrap_or_else(|e| panic!("level{n}: collision: {e}"));
let Some(r) = region else {
empty += 1;
continue;
};
assert_eq!(r.header.header_size, COLLISION_HEADER_SIZE, "level{n}");
assert!(
r.header.payload_size as usize <= r.payload.len(),
"level{n}"
);
if r.payload.is_empty() {
// Present but empty. Counted once, not twice.
empty += 1;
continue;
}
assert_eq!(r.payload.len(), r.header.payload_size as usize, "level{n}");
payload_bytes += r.payload.len();
levels += 1;
}
assert_eq!(
levels + empty,
27,
"expected all 27 levels, got {levels}+{empty}"
);
assert!(
payload_bytes > 10_000_000,
"only {payload_bytes} collision bytes"
);
eprintln!("collision: {payload_bytes} payload bytes across {levels} levels, {empty} empty");
}
/// Moby model geometry: the per-class part table.
///
/// The invariant is `vertex_offset + 16 * vertex_count == next_part`, which is
/// what makes the 16-byte record size and the field boundaries fall out of the
/// data instead of being assumed. The parser rejects any span that violates it,
/// so this test is really checking that no span on the disc does.
#[test]
fn moby_parts_tile_on_every_level() {
require_disc!();
let data = std::env::var_os("GC_EXTRACTED")
.map(PathBuf::from)
.unwrap_or_else(|| {
let home = std::env::var("HOME").unwrap_or_else(|_| ".".to_string());
PathBuf::from(home).join("Documents/gc-extracted")
});
if !data.exists() {
eprintln!("skipped: unpack the disc first");
return;
}
use gc_formats::level_core::LevelCoreHeader;
use gc_formats::moby::parse_moby_geometry;
let mut levels = 0usize;
let mut classes = 0usize;
let mut parts = 0usize;
let mut verts = 0usize;
let mut empties = 0usize;
for n in 0..27 {
let dir = data.join(format!("level{n}"));
let (Ok(core), Ok(index)) = (
std::fs::read(dir.join("core_data.bin")),
std::fs::read(dir.join("core_index.bin")),
) else {
continue;
};
let h = LevelCoreHeader::parse(&index).expect("core header");
let range = h.moby_classes;
assert!(
range.count > 0 && range.offset > 0,
"level{n}: no moby class table"
);
// Class spans tile between consecutive geometry offsets.
let stride = 0x20usize;
let mut offsets: Vec<usize> = (0..range.count as usize)
.map(|i| {
let at = range.offset as usize + i * stride;
let e = gc_formats::level_core::ClassEntry::parse(&index[at..at + stride])
.unwrap_or_else(|e| panic!("level{n}: class {i}: {e}"));
e.offset_in_asset_wad
})
.map(|o| o.max(0) as usize)
.filter(|&o| o > 0)
.collect();
offsets.sort_unstable();
assert!(!offsets.is_empty(), "level{n}: no moby geometry offsets");
for i in 0..offsets.len() {
let start = offsets[i];
let end = offsets.get(i + 1).copied().unwrap_or(core.len());
if end <= start {
continue;
}
let g = parse_moby_geometry(&core[start..end])
.unwrap_or_else(|e| panic!("level{n}: moby class at {start}: {e}"));
if g.is_empty() {
empties += 1;
}
// Every part's vertices are readable and inside the span.
for p in &g.parts {
assert!(
g.vertices(p).is_some(),
"level{n}: part vertices past the end of the class span"
);
}
parts += g.parts.len();
verts += g.vertex_count();
classes += 1;
}
levels += 1;
}
assert_eq!(levels, 27, "expected all 27 levels, got {levels}");
assert!(classes > 4_000, "only {classes} moby class spans");
assert!(parts > 40_000, "only {parts} moby parts");
assert!(verts > 1_200_000, "only {verts} moby vertices");
eprintln!(
"moby: {parts} parts tiling exactly, {verts} vertices, {classes} class spans \
({empties} with no geometry) across {levels} levels"
);
}
/// Shrub class headers and blobs.
///
/// Two fields self-identify exactly on every span, and the parser checks both
/// rather than merely reporting them: `+0x24` must equal the owning class
/// entry's own `o_class`, and `+0x2c` must land inside the span.
///
/// The body is then checked against the R&C1 shape this format follows: a
/// palette of 24 unit-length `s16` normals with a zero pad word, then zero
/// padding records. And the billboard offset at `+0x1c` is checked against the
/// class entry's billboard texture fields, which is the one header field that
/// can be confirmed from a second file.
#[test]
fn shrub_headers_name_their_own_class_on_every_level() {
require_disc!();
let data = std::env::var_os("GC_EXTRACTED")
.map(PathBuf::from)
.unwrap_or_else(|| {
let home = std::env::var("HOME").unwrap_or_else(|_| ".".to_string());
PathBuf::from(home).join("Documents/gc-extracted")
});
if !data.exists() {
eprintln!("skipped: unpack the disc first");
return;
}
use gc_formats::level_core::ShrubClassEntry;
use gc_formats::shrub::{ShrubHeader, SHRUB_CLASS_ENTRY_BYTES, SHRUB_NORMAL_COUNT};
let mut levels = 0usize;
let mut spans = 0usize;
let mut absent = 0usize;
let (mut min_size, mut max_size) = (f32::MAX, 0.0f32);
let mut scratch_nonzero = 0usize;
let mut mode_hist: std::collections::BTreeMap<u16, usize> = Default::default();
let mut scratch_hist: std::collections::BTreeMap<u16, usize> = Default::default();
let mut radius_range = (f32::MAX, 0f32);
let mut scale_range = (f32::MAX, 0f32);
let mut bounded_records = 0usize;
let mut bounded_bodies = 0usize;
let mut palette_records = 0usize;
let mut padding_records = 0usize;
let mut norm2_deviation = 0i64;
let mut billboards = 0usize;
let mut billboard_entries = 0usize;
let mut packets_total = 0usize;
let mut packet_headers_total = 0usize;
for n in 0..27 {
let dir = data.join(format!("level{n}"));
let (Ok(core), Ok(index)) = (
std::fs::read(dir.join("core_data.bin")),
std::fs::read(dir.join("core_index.bin")),
) else {
continue;
};
let h = gc_formats::level_core::LevelCoreHeader::parse(&index).expect("core header");
let range = h.shrub_classes;
// Class spans tile between consecutive geometry offsets, with the last
// one bounded by the chunk container. It is found by signature, since
// the core index carries no successor offset for shrub; without it the
// last class absorbs the container and the body check measures its
// neighbours.
let mut offsets: Vec<usize> = Vec::new();
for i in 0..range.count.max(0) as usize {
let at = range.offset.max(0) as usize + i * SHRUB_CLASS_ENTRY_BYTES;
let e = ShrubClassEntry::parse(&index[at..at + SHRUB_CLASS_ENTRY_BYTES])
.unwrap_or_else(|e| panic!("level{n}: shrub class {i}: {e}"));
if e.base.offset_in_asset_wad > 0 {
offsets.push(e.base.offset_in_asset_wad as usize);
}
}
offsets.sort_unstable();
// Levels without shrub geometry have no span to bound. The container
// that follows tie on those levels is checked by
// `chunk_container_closes_the_last_class_region`.
let container = match offsets.last() {
Some(&last) if !offsets.is_empty() => {
gc_formats::chunks::chunk_region_start(&core, last).unwrap_or_else(|| {
panic!("level{n}: no chunk container after the shrub classes")
})
}
_ => core.len(),
};
let mut span_end_of: std::collections::HashMap<usize, usize> =
std::collections::HashMap::new();
for (i, &o) in offsets.iter().enumerate() {
let end = offsets.get(i + 1).copied().unwrap_or(container);
span_end_of.insert(o, end);
}
for i in 0..range.count.max(0) as usize {
let at = range.offset.max(0) as usize + i * SHRUB_CLASS_ENTRY_BYTES;
let e = ShrubClassEntry::parse(&index[at..at + SHRUB_CLASS_ENTRY_BYTES])
.unwrap_or_else(|e| panic!("level{n}: shrub class {i}: {e}"));
let (span_end, has_successor) =
match span_end_of.get(&(e.base.offset_in_asset_wad.max(0) as usize)) {
Some(&e2) => (e2, true),
None => (core.len(), false),
};
match ShrubHeader::region(&core, e.base.offset_in_asset_wad, e.base.o_class, span_end) {
Ok(Some(mut s)) => {
s.span_end_is_a_successor = has_successor;
// Every class is bounded now, so every body must be whole
// 8-byte records. That was not assertable while the last
// class ran to the lump's end, and it is the check the
// boundary earns its keep for.
assert!(
s.body_is_well_formed(),
"level{n} class {i}: shrub body is not whole 8-byte records"
);
bounded_bodies += 1;
bounded_records += s.body_record_count();
assert_eq!(
s.header.o_class,
e.base.o_class.max(0) as u32,
"level{n} class {i}"
);
assert!(!s.data.is_empty(), "level{n} class {i}: empty shrub data");
assert!(
s.header.sphere.iter().all(|v| v.is_finite()),
"level{n} class {i}: non-finite shrub sphere"
);
assert!(
s.header.size.is_finite() && s.header.size > 0.0,
"level{n} class {i}: shrub size {}",
s.header.size
);
// The scratch word is zero on every span; the parser
// refuses anything else. `mode_bits` is 4 on 16 spans and
// is reported rather than asserted. On those 16 the word
// at +0x14 reads as an f32 denormal, which the Emotion
// Engine flushes to zero like everything else.
if s.header.scratch != 0 {
scratch_nonzero += 1;
}
*mode_hist.entry(s.header.mode_bits).or_default() += 1;
*scratch_hist.entry(s.header.scratch).or_default() += 1;
radius_range.0 = radius_range.0.min(s.header.sphere[3]);
radius_range.1 = radius_range.1.max(s.header.sphere[3]);
scale_range.0 = scale_range.0.min(s.header.scale);
scale_range.1 = scale_range.1.max(s.header.scale);
min_size = min_size.min(s.header.size);
max_size = max_size.max(s.header.size);
// The palette: 24 unit normals, then zero padding.
let normals: Vec<_> = s.normals().collect();
assert_eq!(
normals.len(),
SHRUB_NORMAL_COUNT,
"level{n} class {i}: palette is {} entries, not {SHRUB_NORMAL_COUNT}",
normals.len()
);
for (k, normal) in normals.iter().enumerate() {
assert!(
normal.is_unit(),
"level{n} class {i}: palette entry {k} {normal:?} is not a unit normal"
);
let n2 = (normal.x as i64).pow(2)
+ (normal.y as i64).pow(2)
+ (normal.z as i64).pow(2);
norm2_deviation = norm2_deviation.max((n2 - 32767i64.pow(2)).abs());
}
palette_records += normals.len();
for (k, record) in s.body_records().skip(SHRUB_NORMAL_COUNT).enumerate() {
assert!(
record.iter().all(|&b| b == 0),
"level{n} class {i}: padding record {k} is not all zero"
);
}
padding_records += s.padding_record_count();
// The packets: the table at +0x40 tiles the span from
// align16 of its own end to the palette, or to the
// billboard when the class has one. This is what puts the
// mesh geometry in the blob, and it is the identity that
// makes `count` the packet count rather than a guess.
let packets = s.packets().unwrap_or_else(|| {
panic!("level{n} class {i}: packet table does not tile")
});
assert_eq!(
packets.len(),
s.header.count as usize,
"level{n} class {i}: packet count disagrees with the header"
);
packets_total += packets.len();
// The packet headers themselves. The disc form is a fixed
// signature -- magic, four zero bytes, tag 0x05 -- and the
// loader rewrites bytes 8-15 on load, so the count and the
// pointer live in RAM, not here.
let hdrs: Vec<_> = s.packet_headers().collect();
assert_eq!(
hdrs.len(),
packets.len(),
"level{n} class {i}: header count disagrees with packet count"
);
for (pi, h) in hdrs.iter().enumerate() {
assert!(
h.is_some(),
"level{n} class {i}: packet {pi} header does not match the \
disc invariants (magic 04 04 00 01, bytes 4-8 zero, tag 0x05)"
);
assert_eq!(
packets[pi].size % 16,
0,
"level{n} class {i}: packet {pi} size is not a multiple of 16"
);
}
packet_headers_total += hdrs.len();
// The billboard: present exactly when the class entry
// carries billboard texture fields.
let entry_has_billboard = e.billboard_width != 0 || e.billboard_height != 0;
match s.billboard().expect("billboard parses") {
Some(b) => {
billboards += 1;
assert!(
entry_has_billboard,
"level{n} class {i}: billboard record without billboard texture fields"
);
assert_eq!(b.tex1_addr, 0x14, "level{n} class {i}: TEX1 address");
assert_eq!(b.tex0_addr, 0x06, "level{n} class {i}: TEX0 address");
assert_eq!(b.miptbp_addr, 0x34, "level{n} class {i}: MIPTBP address");
assert_eq!(b.mmin, 4, "level{n} class {i}: MMIN");
}
None => assert!(
!entry_has_billboard,
"level{n} class {i}: billboard texture fields with no billboard record"
),
}
if entry_has_billboard {
billboard_entries += 1;
}
spans += 1;
}
Ok(None) => absent += 1,
Err(err) => panic!("level{n}: shrub class {i}: {err}"),
}
}
levels += 1;
}
assert_eq!(levels, 27, "expected all 27 levels, got {levels}");
assert_eq!(
spans + absent,
358,
"expected 358 shrub classes, got {}",
spans + absent
);
assert!(spans > 340, "only {spans} shrub spans with geometry");
// The container bounds every class now, so every body is checkable.
assert_eq!(bounded_bodies, spans, "every shrub class should be bounded");
assert_eq!(scratch_nonzero, 0, "the scratch word is zero on every span");
assert_eq!(
billboards, billboard_entries,
"billboard records and billboard class entries disagree: \
{billboards} records vs {billboard_entries} entries"
);
eprintln!(
"shrub: {spans} headers naming their own class, {absent} without geometry; \
all {bounded_bodies} bodies bounded, {bounded_records} records, \
{palette_records} of them palette normals and {padding_records} zero padding; \
{billboards} billboards, all with texture fields; \
{packets_total} packets across all blobs, {packet_headers_total} headers; \
mode_bits {mode_hist:?}, radius {radius_range:?}, scale {scale_range:?}, \
largest palette deviation from unit length {norm2_deviation} of a possible 65535"
);
}
/// Region bounds derived from successor boundaries, on every level.
///
/// Every region is closed by the next region's start, or -- for the last class
/// region -- by the located chunk container, never by `core_data.len()`, so no
/// span silently absorbs the tail of the lump the way the last shrub class was
/// doing.
#[test]
fn core_regions_chain_on_every_level() {
require_disc!();
let data = std::env::var_os("GC_EXTRACTED")
.map(PathBuf::from)
.unwrap_or_else(|| {
let home = std::env::var("HOME").unwrap_or_else(|_| ".".into());
PathBuf::from(home).join("Documents/gc-extracted")
});
if !data.exists() {
eprintln!("skipped: unpack the disc first");
return;
}
use gc_formats::level_core::LevelCoreHeader;
use gc_formats::regions::{core_layout, CORE_DATA_TRAILER_BYTES};
let mut levels = 0usize;
let mut unresolved_shrub = 0usize;
let mut unresolved_chunks = 0usize;
let mut bounded = 0usize;
let mut shrub_bytes = 0usize;
let mut chunk_bytes = 0usize;
let (mut first, mut last) = (usize::MAX, 0usize);
for n in 0..27 {
let dir = data.join(format!("level{n}"));
let (Ok(core), Ok(index)) = (
std::fs::read(dir.join("core_data.bin")),
std::fs::read(dir.join("core_index.bin")),
) else {
continue;
};
let core_len = core.len();
let h = LevelCoreHeader::parse(&index).expect("core header");
let regions = core_layout(&index, &core, &h);
// Regions appear in order, never overlap, and never run past the lump.
for pair in regions.windows(2) {
assert!(
pair[0].start <= pair[1].start,
"level{n}: {} vs {}",
pair[0].name,
pair[1].name
);
if let Some(end) = pair[0].end {
assert!(
end <= pair[1].start,
"level{n}: {} ends after {}",
pair[0].name,
pair[1].name
);
}
}
for r in &regions {
assert!(
r.start < core_len,
"level{n}: {} starts past the lump",
r.name
);
if let Some(end) = r.end {
assert!(end <= core_len, "level{n}: {} ends past the lump", r.name);
}
}
// Regions appear in the canonical order, but not every level has every
// region -- level 10 has no occlusion and no shrub at all.
const ORDER: [&str; 8] = [
"tfrags",
"occlusion",
"sky",
"collision",
"moby",
"tie",
"shrub",
"chunks",
];
let names: Vec<_> = regions.iter().map(|r| r.name).collect();
let ranks: Vec<usize> = names
.iter()
.map(|name| {
ORDER
.iter()
.position(|o| o == name)
.unwrap_or_else(|| panic!("level{n}: unknown region {name}"))
})
.collect();
assert!(
ranks.windows(2).all(|w| w[0] < w[1]),
"level{n}: regions out of order: {names:?}"
);
if let Some(s) = regions.iter().find(|r| r.name == "shrub") {
match s.end {
Some(e) => {
// The container's start, not the trailer and not the lump's
// end: the trailer is the chunk region's business.
assert!(e < core_len - CORE_DATA_TRAILER_BYTES);
shrub_bytes += s.len().unwrap_or(0);
bounded += 1;
}
None => unresolved_shrub += 1,
}
first = first.min(s.start);
last = last.max(s.start);
}
if let Some(c) = regions.iter().find(|r| r.name == "chunks") {
match c.end {
Some(e) => {
// The trailer is the only thing past the chunk container.
assert_eq!(e, core_len - CORE_DATA_TRAILER_BYTES);
chunk_bytes += c.len().unwrap_or(0);
}
None => unresolved_chunks += 1,
}
}
levels += 1;
}
assert_eq!(levels, 27, "expected all 27 levels, got {levels}");
assert_eq!(
unresolved_shrub, 0,
"every level with shrub should bound it at the chunk container"
);
assert_eq!(bounded, 24, "expected 24 levels with a shrub region");
assert_eq!(
unresolved_chunks, 0,
"every chunk region should end at the trailer"
);
eprintln!(
"regions: shrub starts {first}..{last}; {shrub_bytes} bytes of shrub and \
{chunk_bytes} bytes of chunk data, shrub closed by the located container on \
all {bounded} levels"
);
}
/// The post-shrub chunk container: chunks carry the `0xf0`-tagged offset
/// signature on every level, and their offsets resolve to records with a
/// shared field layout.
///
/// The region is bounded properly rather than by the fixed window this test
/// first used: it runs from the marker-paired chunk signature that closes the
/// last class region to the constant trailer. The window approach worked and
/// then over-worked -- a fixed 900,000 bytes from the end reaches past the
/// container on some levels and stops inside it on others, which is how 27
/// chunks came to be truncated at a "window edge" that is not a format
/// boundary. The locator is asserted by
/// `chunk_container_closes_the_last_class_region`.
///
/// The layout facts asserted here are measured, not assumed:
///
/// - every tagged offset has top byte `0xf0`, on all 27 levels;
/// - resolving records at `chunk_start + low` gives 17-21% byte positions
/// constant across that chunk's own records, which does not happen by
/// chance and is what distinguishes this from a coincidental byte pattern;
/// - stride is a per-chunk property, not a region-wide one.
#[test]
fn chunk_containers_resolve_on_every_level() {
require_disc!();
let data = std::env::var_os("GC_EXTRACTED")
.map(PathBuf::from)
.unwrap_or_else(|| {
let home = std::env::var("HOME").unwrap_or_else(|_| ".".into());
PathBuf::from(home).join("Documents/gc-extracted")
});
if !data.exists() {
eprintln!("skipped: unpack the disc first");
return;
}
use gc_formats::level_core::LevelCoreHeader;
use gc_formats::regions::{core_layout, CORE_DATA_TRAILER_BYTES};
let mut levels = 0usize;
let mut chunks = 0usize;
let mut records = 0usize;
let mut strides = std::collections::BTreeSet::new();
let mut truncated = 0usize;
let mut constant_total = 0usize;
let mut stride_total = 0usize;
let mut frac: Vec<f64> = Vec::new();
for n in 0..27 {
let dir = data.join(format!("level{n}"));
let (Ok(core), Ok(index)) = (
std::fs::read(dir.join("core_data.bin")),
std::fs::read(dir.join("core_index.bin")),
) else {
continue;
};
// The region runs from the chunk signature that closes the last class
// region to the constant trailer, both measured and identical in size
// on all 27 levels. core_layout locates the start through the same
// signature the chunk parser uses.
let h = LevelCoreHeader::parse(&index).expect("core header");
let Some(region) = core_layout(&index, &core, &h)
.into_iter()
.find(|r| r.name == "chunks")
else {
continue;
};
let Some(end) = region.end else {
panic!("level{n}: chunk region is unbounded");
};
assert_eq!(end, core.len() - CORE_DATA_TRAILER_BYTES);
assert!(!region.is_empty(), "level{n}: empty chunk region");
let region = &core[region.start..end];
let found = gc_formats::chunks::parse_all_chunks(region).expect("chunks should parse");
if found.is_empty() {
continue;
}
levels += 1;
for chunk in &found {
assert!(
!chunk.chunk.offsets.is_empty(),
"level{n}: chunk at {} has no offsets",
chunk.chunk.offset
);
assert!(chunk.chunk.stride > 0, "level{n}: zero stride");
// The one decoded header field.
assert_eq!(
chunk.chunk.count as usize,
chunk.chunk.offsets.len(),
"level{n}: chunk at {} header count {} but {} offsets",
chunk.chunk.offset,
chunk.chunk.count,
chunk.chunk.offsets.len()
);
chunks += 1;
records += chunk.records.len();
strides.insert(chunk.chunk.stride);
// Records resolve unless the last one would run past the region
// end, which happens for the chunk sitting at the trailer end:
// the container's records stop there, so its final record or two
// fall outside. Truncation is counted rather than asserted away.
assert!(
chunk.records.len() <= chunk.chunk.offsets.len(),
"level{n}: chunk at {} resolved MORE records than offsets",
chunk.chunk.offset
);
if chunk.records.len() < chunk.chunk.offsets.len() {
truncated += 1;
}
// The invariant that makes this a container and not a coincidence.
// Accumulated rather than asserted per chunk: individual chunks
// range from ~7% to ~21% constant positions, so a per-chunk
// threshold would be asserting a property the format does not have.
let constant = constant_positions(&chunk.records);
constant_total += constant;
stride_total += chunk.chunk.stride;
frac.push(constant as f64 / chunk.chunk.stride as f64);
}
}
assert_eq!(levels, 27, "expected all 27 levels, got {levels}");
assert!(chunks > 500, "only {chunks} chunks resolved");
assert!(records > 5_000, "only {records} records resolved");
assert!(
strides.len() > 5,
"stride should vary per chunk, saw {}",
strides.len()
);
// Chance would give a constant position a probability of 1/256^n, so even
// 5% across tens of thousands of records is far above noise.
let mean_frac = constant_total as f64 / stride_total as f64;
assert!(
mean_frac > 0.05,
"constant positions {constant_total}/{stride_total} = {mean_frac:.3} is near chance"
);
eprintln!(
"chunks: {chunks} over {levels} levels, {records} records, {} distinct strides, \
constant {constant_total}/{stride_total} ({:.1}%), per-chunk min {:.1}% max {:.1}%, \
{truncated} chunks truncated at the trailer end",
strides.len(),
mean_frac * 100.0,
frac.iter().cloned().fold(f64::INFINITY, f64::min) * 100.0,
frac.iter().cloned().fold(0.0, f64::max) * 100.0,
);
}
/// The chunk container closes the last class region, on every level.
///
/// The core index carries no successor offset for shrub -- unlike moby and
/// tie, whose boundaries fall out of the class tables -- so the boundary is
/// located in `core_data`: the constant marker pair sitting immediately in
/// front of a chunk signature. Both halves of that signature are weak alone,
/// which is why the test measures them separately:
///
/// - the marker pair `f6 7c` occurs 25 to 103 times in a 5 to 17 MB lump, so
/// on its own it means nothing;
/// - the chunk shape (16-byte header ending `0xff`, 10 zeros, tagged offsets)
/// matches random data often enough to need four tagged offsets before it
/// means anything.
///
/// Together they are exact: on all 27 levels the marker sits exactly two bytes
/// before the first chunk header. Three checks pin that down per level:
///
/// 1. the located boundary carries the marker;
/// 2. the last shrub body walks to 8-byte records that end exactly where the
/// signature begins, with no chunk signature inside the body itself;
/// 3. the container's records fill the region up to the constant trailer.
///
/// Levels without shrub are the control for the locator: there the container
/// closes tie instead, and the same marker precedes it.
#[test]
fn chunk_container_closes_the_last_class_region() {
require_disc!();
let data = std::env::var_os("GC_EXTRACTED")
.map(PathBuf::from)
.unwrap_or_else(|| {
let home = std::env::var("HOME").unwrap_or_else(|_| ".".into());
PathBuf::from(home).join("Documents/gc-extracted")
});
if !data.exists() {
eprintln!("skipped: unpack the disc first");
return;
}
use gc_formats::chunks::{self, CHUNK_REGION_MARKER};
use gc_formats::level_core::{LevelCoreHeader, ShrubClassEntry};
use gc_formats::regions::{core_layout, last_geometry, CORE_DATA_TRAILER_BYTES};
use gc_formats::shrub::{ShrubHeader, SHRUB_CLASS_ENTRY_BYTES};
let mut levels = 0usize;
let mut with_shrub = 0usize;
let mut marker_wide_max = 0usize;
let mut body_records = 0usize;
let mut container_bytes = 0usize;
let mut fill_gap_max = 0usize;
for n in 0..27 {
let dir = data.join(format!("level{n}"));
let (Ok(core), Ok(index)) = (
std::fs::read(dir.join("core_data.bin")),
std::fs::read(dir.join("core_index.bin")),
) else {
panic!("level{n}: missing core_data or core_index");
};
let trailer = core.len() - CORE_DATA_TRAILER_BYTES;
let h = LevelCoreHeader::parse(&index).expect("core header");
let last_shrub = last_geometry(&index, h.shrub_classes, SHRUB_CLASS_ENTRY_BYTES);
let last_tie = last_geometry(&index, h.tie_classes, 0x20);
// The container follows the last of the shrub and tie classes, so the
// signature search starts after the class bodies rather than inside
// them.
let scan_from = last_shrub
.or(last_tie)
.unwrap_or_else(|| panic!("level{n}: no class geometry to follow"));
let container = chunks::chunk_region_start(&core, scan_from)
.unwrap_or_else(|| panic!("level{n}: no chunk container after {scan_from}"));
// 1. The marker, and how common it is without the signature behind it.
assert_eq!(
&core[container - 2..container],
&CHUNK_REGION_MARKER,
"level{n}: container at {container} is not preceded by the marker"
);
marker_wide_max = marker_wide_max.max(
core.windows(2)
.filter(|w| *w == CHUNK_REGION_MARKER)
.count(),
);
// 2. The last shrub body ends exactly at the marker. This is the check
// that the boundary is the successor of shrub rather than a coincident
// pair inside it.
if let Some(last) = last_shrub {
let o_class = (0..h.shrub_classes.count.max(0) as usize)
.filter_map(|i| {
let at = h.shrub_classes.offset.max(0) as usize + i * SHRUB_CLASS_ENTRY_BYTES;
let e = ShrubClassEntry::parse(
index
.get(at..at + SHRUB_CLASS_ENTRY_BYTES)
.unwrap_or_default(),
)
.ok()?;
(e.base.offset_in_asset_wad == last as i32).then_some(e.base.o_class)
})
.next()
.unwrap_or_else(|| panic!("level{n}: no shrub class at {last}"));
let span = ShrubHeader::region(&core, last as i32, o_class, trailer)
.expect("last shrub span parses")
.expect("last shrub span present");
let data_start = last + span.header.data_offset as usize;
// Walk 8-byte records, bounded by the container so the walk can
// never continue into the chunk region itself.
let mut at = data_start;
while at + 8 <= container && core[at + 6] == 0 && core[at + 7] == 0 {
at += 8;
}
assert_eq!(
at + 2,
container,
"level{n}: shrub body at {data_start} does not end at the marker"
);
assert!(at > data_start, "level{n}: last shrub body is empty");
body_records += (at - data_start) / 8;
// No chunk signature inside the body: the search for the boundary
// must not match one it should have skipped.
let sig_inside = (last..container - 2).any(|off| chunks::is_chunk_start(&core, off, 4));
assert!(
!sig_inside,
"level{n}: chunk signature inside the last shrub body"
);
with_shrub += 1;
} else {
// Without shrub the container closes tie, and the marker precedes
// it the same way -- the locator is not shrub-specific.
let tie = core_layout(&index, &core, &h)
.into_iter()
.find(|r| r.name == "tie")
.unwrap_or_else(|| panic!("level{n}: no tie region to close"));
assert_eq!(
tie.end,
Some(container),
"level{n}: tie must end at the container"
);
}
// 3. The container fills its region up to the constant trailer: the
// furthest record should reach within a few KB of it, never inside it.
let region = &core[container..trailer];
let found = chunks::parse_all_chunks(region).expect("chunks should parse");
let region_ptr = region.as_ptr() as usize;
let furthest = found
.iter()
.flat_map(|c| {
c.records
.iter()
.map(move |r| r.as_ptr() as usize + r.len() - region_ptr)
})
.max()
.unwrap_or(0);
assert!(
region.len() - furthest < 4096,
"level{n}: chunk records stop {} bytes short of the trailer",
region.len() - furthest
);
container_bytes += region.len();
fill_gap_max = fill_gap_max.max(region.len() - furthest);
levels += 1;
}
assert_eq!(levels, 27, "expected all 27 levels, got {levels}");
assert_eq!(
with_shrub, 24,
"expected 24 levels with shrub, got {with_shrub}"
);
eprintln!(
"container: {levels} levels ({with_shrub} closing shrub), \
{body_records} 8-byte records in last-shrub bodies, \
{container_bytes} bytes of chunk data, largest trailer gap {fill_gap_max}, \
marker pair occurs at most {marker_wide_max} times per lump"
);
}
/// The chunk record's leading word is fixed per type.
///
/// A record is `[leading u16][two index bytes][payload]`. Measured on the
/// disc: the word is the same at every record of a chunk on 1,439 of 1,509
/// chunks (`None` on the 70 that vary, which the parser reports rather than
/// averaging), and fixed within every chunk type, taking only the values
/// 1, 2, 4, 6, 8 and 10.
///
/// Not named. What the value counts is not established, and two readings were
/// measured and disproved: it is not the payload's entry count -- the payload
/// length divided by it leaves 57 distinct fractional "sizes" -- and it is not
/// the number of distinct leading bytes, which agrees on 0 of 1,506 chunks.
/// See `docs/formats/core-data-regions.md`.
#[test]
fn chunk_record_leading_word_is_fixed_per_type() {
require_disc!();
let data = std::env::var_os("GC_EXTRACTED")
.map(PathBuf::from)
.unwrap_or_else(|| {
let home = std::env::var("HOME").unwrap_or_else(|_| ".".into());
PathBuf::from(home).join("Documents/gc-extracted")
});
if !data.exists() {
eprintln!("skipped: unpack the disc first");
return;
}
use gc_formats::chunks::parse_all_chunks;
use std::collections::BTreeMap;
// header -> the words its chunks carry, and the value histogram. Chunks
// whose own records disagree are counted apart rather than folded in.
let mut by_type: BTreeMap<[u8; 16], BTreeSet<u16>> = BTreeMap::new();
let mut histogram: BTreeMap<u16, usize> = BTreeMap::new();
let mut levels = 0usize;
let mut chunks = 0usize;
let mut varying = 0usize;
for n in 0..27 {
let core = match std::fs::read(data.join(format!("level{n}/core_data.bin"))) {
Ok(c) => c,
Err(_) => continue,
};
let found = parse_all_chunks(&core).expect("chunks should parse");
if found.is_empty() {
continue;
}
levels += 1;
for c in &found {
chunks += 1;
match c.chunk.prefix {
Some(p) => {
by_type.entry(c.chunk.header).or_default().insert(p);
*histogram.entry(p).or_default() += 1;
}
None => varying += 1,
}
}
}
assert!(levels >= 25, "only {levels} levels carry chunks");
assert!(chunks > 1400, "only {chunks} chunks parsed");
// The word is uniform within a chunk on all but a small minority.
let uniform = chunks - varying;
assert!(
uniform > 1400,
"only {uniform} of {chunks} chunks carry a uniform leading word"
);
// Fixed within every type: no type's chunks carry two different words.
let varying_types: Vec<_> = by_type.iter().filter(|(_, v)| v.len() > 1).collect();
assert!(
varying_types.is_empty(),
"{} types carry more than one leading word",
varying_types.len()
);
// The word is never zero and never large, and it is not the record count:
// 621 chunks carry 2, 520 carry 4, and the rest are spread thin.
assert!(
histogram.keys().all(|&p| p > 0 && p <= 16),
"prefix values {histogram:?}"
);
let two = histogram.get(&2).copied().unwrap_or(0);
let four = histogram.get(&4).copied().unwrap_or(0);
assert!(two > 500, "only {two} chunks carry the word 2");
assert!(four > 400, "only {four} chunks carry the word 4");
eprintln!(
"chunk leading word: {uniform} of {chunks} chunks uniform ({varying} vary), \
{} types, values {histogram:?}",
by_type.len()
);
}
/// The tie record is R&C1's `TiePacketHeader`, and its rule holds.
///
/// A tie LOD block is a table of 16-byte packet headers -- a data pointer,
/// then R&C1's byte fields at +4..+0x10. What identifies them rather than a
/// resemblance is R&C1's own documented rule: **`bfc_distance == 5 *
/// shader_count` on every record**, here 15,219 of 15,219 over 2,177 blocks on
/// all 27 levels.
///
/// Measured over the same set, and reported rather than asserted because they
/// are not universal:
///
/// * `color_ofs == vert_size` on 12,640 of 15,219 -- and R&C1's rule for the
/// field (`== vert_ofs + vert_size`) holds on **0**, so the two games use it
/// differently and this one is named for what it measures;
/// * `color_count`, `strip_count`, `strip_vertex_count` zero on ~15,077 of
/// 15,219;
/// * the orderings `vert_ofs <= vert_size`, `scissor_size <= scissor_ofs` and
/// `control_size <= control_count` on all of them.
///
/// One claim is retracted here rather than softened: a packet-length formula,
/// `(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). It
/// was measured over blocks found by reading `packets[2]` where `packets[1]`
/// was meant, so the arithmetic agreed perfectly with a population that was not
/// the tie blocks. The block set was the error; see `AGENTS.md` rule 3.
#[test]
fn tie_records_are_packet_headers() {
require_disc!();
let data = std::env::var_os("GC_EXTRACTED")
.map(PathBuf::from)
.unwrap_or_else(|| {
let home = std::env::var("HOME").unwrap_or_else(|_| ".".into());
PathBuf::from(home).join("Documents/gc-extracted")
});
if !data.exists() {
eprintln!("skipped: unpack the disc first");
return;
}
use gc_formats::level_core::LevelCoreHeader;
use gc_formats::tie::{parse_tie_block, resolve_tie_class, TieRecord};
let mut levels = 0usize;
let mut blocks = 0usize;
let mut records = 0usize;
let mut bfc_ok = 0usize;
let mut invariants_ok = 0usize;
let (mut color_eq_size, mut color_zero, mut strips_zero, mut strip_verts_zero) =
(0usize, 0usize, 0usize, 0usize);
for n in 0..27 {
let (Ok(core), Ok(index)) = (
std::fs::read(data.join(format!("level{n}/core_data.bin"))),
std::fs::read(data.join(format!("level{n}/core_index.bin"))),
) else {
continue;
};
let h = LevelCoreHeader::parse(&index).expect("core header");
for c in 0..h.tie_classes.count.max(0) as usize {
let Ok(class) = resolve_tie_class(&index, &core, h.tie_classes, c) else {
continue;
};
for lod in 1..=2usize {
let off = class.header.packets[lod];
if off <= 0 {
continue;
}
let start = class.entry.offset_in_asset_wad as usize + off as usize;
let Some(block) = parse_tie_block(&core, start) else {
continue;
};
let len = 0x10 + block.payload.len() + block.padding.len();
let Some(slice) = core.get(start..start + len) else {
continue;
};
// The table must fit inside the block the terminator found, or
// what follows is being read as a table.
if block.header.data_offset as usize > 0x10 + block.payload.len() {
continue;
}
blocks += 1;
for r in block
.header
.records(slice)
.map(|r| TieRecord::parse(r).expect("record parses"))
{
records += 1;
bfc_ok += usize::from(r.bfc_distance == 5 * r.shader_count);
invariants_ok += usize::from(r.invariants_hold());
color_eq_size += usize::from(r.color_ofs == r.vert_size);
color_zero += usize::from(r.color_count == 0);
strips_zero += usize::from(r.strip_count == 0);
strip_verts_zero += usize::from(r.strip_vertex_count == 0);
}
}
}
levels += 1;
}
assert!(levels >= 25, "only {levels} levels were read");
assert_eq!(blocks, 2_177, "expected 2,177 tie blocks, got {blocks}");
assert!(records > 14_000, "only {records} packet headers found");
// The identification: R&C1's rule, on every record.
assert_eq!(
bfc_ok,
records,
"bfc_distance != 5 * shader_count on {} of {records}",
records - bfc_ok
);
assert_eq!(
invariants_ok,
records,
"record invariants failed on {} of {records}",
records - invariants_ok
);
eprintln!(
"tie packet headers: {records} over {levels} levels, {blocks} blocks; \
bfc_distance == 5*shader_count on all; orderings on all; \
color_ofs == vert_size on {color_eq_size}/{records}; \
color_count/strip_count/strip_vertex_count zero on \
{color_zero}/{strips_zero}/{strip_verts_zero}"
);
}
/// The tie class header's `+0x0c` word is the three LOD record counts.
///
/// The word was read as R&C1's 64-light-slot *normals offset* and skipped for
/// two commits, which was the right thing to do with the wrong information: the
/// byte at `+0x0c` is not an offset at all. It is the **record count of the LOD
/// 0 block**, `+0x0d` of LOD 1 and `+0x0e` of LOD 2 -- verified on **1,864 of
/// 1,864** classes across all 27 levels. R&C1 carries the same quadruple at
/// `+0x20`; R&C2 has it here.
///
/// The check is not circular: the counts are read from the header, and
/// compared against the record tables the blocks themselves carry, which are
/// reached through `packets[]` and delimited by the terminator. Two independent
/// paths to the same number.
///
/// The fourth byte, `+0x0f`, is left unnamed. It is *not* the shader (ad-gif)
/// total, which disagrees on 1,827 of the classes measured here.
#[test]
fn tie_class_header_counts_records_per_lod() {
require_disc!();
let data = std::env::var_os("GC_EXTRACTED")
.map(PathBuf::from)
.unwrap_or_else(|| {
let home = std::env::var("HOME").unwrap_or_else(|_| ".".into());
PathBuf::from(home).join("Documents/gc-extracted")
});
if !data.exists() {
eprintln!("skipped: unpack the disc first");
return;
}
use gc_formats::level_core::{ClassEntry, LevelCoreHeader};
use gc_formats::tie::{parse_tie_block, TieClassHeader, TieRecord};
let mut levels = 0usize;
let mut classes = 0usize;
let mut byte_matches = [0usize; 3];
let mut per_class_all_three = 0usize;
let mut fourth_bad = 0usize;
let mut fourth_range = (u8::MAX, 0u8);
for lv in 0..27usize {
let (Ok(idx), Ok(core)) = (
std::fs::read(data.join(format!("level{lv}/core_index.bin"))),
std::fs::read(data.join(format!("level{lv}/core_data.bin"))),
) else {
continue;
};
let t = LevelCoreHeader::parse(&idx).expect("hdr").tie_classes;
levels += 1;
for c in 0..t.count as usize {
let o = t.offset as usize + c * 0x20;
let e = ClassEntry::parse(&idx[o..o + 0x20]).expect("entry");
let base = e.offset_in_asset_wad as usize;
if base == 0 || base + 0x30 > core.len() {
continue;
}
let Ok(hdr) = TieClassHeader::parse(&core[base..base + 0x48]) else {
continue;
};
// The record tables, from the blocks themselves.
let mut counts = [0usize; 3];
let mut shader_total = 0usize;
for (lod, count) in counts.iter_mut().enumerate() {
let off = hdr.packets[lod];
if off <= 0 {
continue;
}
let s = base + off as usize;
if let Some(blk) = parse_tie_block(&core, s) {
let recs: Vec<&[u8]> = blk.header.records(&core[s..]).collect();
*count = recs.len();
for rec in recs {
if let Ok(r) = TieRecord::parse(rec) {
shader_total += r.shader_count as usize;
}
}
}
}
classes += 1;
for (lod, slot) in byte_matches.iter_mut().enumerate() {
*slot += usize::from(hdr.packet_counts[lod] as usize == counts[lod]);
}
per_class_all_three +=
usize::from((0..3).all(|l| hdr.packet_counts[l] as usize == counts[l]));
if hdr.unknown_0f as usize != shader_total {
fourth_bad += 1;
}
fourth_range.0 = fourth_range.0.min(hdr.unknown_0f);
fourth_range.1 = fourth_range.1.max(hdr.unknown_0f);
}
}
assert!(levels >= 25, "only {levels} levels were read");
assert_eq!(classes, 1_864, "expected 1,864 tie classes, got {classes}");
for (lod, &matched) in byte_matches.iter().enumerate() {
assert_eq!(
matched,
classes,
"LOD{lod} record count byte disagrees on {} of {classes}",
classes - matched
);
}
assert_eq!(
per_class_all_three, classes,
"all three bytes match on {} of {classes}",
per_class_all_three
);
eprintln!(
"tie class header +0x0c: LOD0/LOD1/LOD2 record counts on {classes} classes; \
+0x0f range {}..{}, not the shader total on {}",
fourth_range.0, fourth_range.1, fourth_bad
);
}
/// Byte positions that hold the same value in every supplied record.
fn constant_positions(records: &[&[u8]]) -> usize {
let Some(first) = records.first() else {
return 0;
};
// Records in one chunk are NOT all the same length: the offset deltas vary,
// and `resolve` measures each record against its successor. Compare only the
// span every record has, or this indexes past the short ones.
let len = records.iter().map(|r| r.len()).min().unwrap_or(0);
(0..len)
.filter(|&i| records.iter().all(|r| r[i] == first[i]))
.count()
}
/// The sky block: the sub-object table at `+0x20` enumerates the sub-objects on
/// every level, and each carries a bounding sphere and texture dimensions.
///
/// The word at `+0x0c` is deliberately **not** asserted to be a count: it
/// disagrees with the table on most levels. See `gc_formats::sky`.
#[test]
fn sky_sub_objects_parse_on_every_level() {
require_disc!();
let data = std::env::var_os("GC_EXTRACTED")
.map(PathBuf::from)
.unwrap_or_else(|| {
let home = std::env::var("HOME").unwrap_or_else(|_| ".".to_string());
PathBuf::from(home).join("Documents/gc-extracted")
});
if !data.exists() {
eprintln!("skipped: unpack the disc first");
return;
}
let mut levels = 0usize;
let mut total = 0usize;
let mut radii = (f32::MAX, f32::MIN);
let mut counts = (u32::MAX, 0u32);
let mut dims = (u16::MAX, 0u16);
let mut nonzero_radius = 0usize;
let mut reserved_nonzero = 0usize;
for n in 0..27 {
let dir = data.join(format!("level{n}"));
let core = match std::fs::read(dir.join("core_data.bin")) {
Ok(c) => c,
Err(_) => continue,
};
let index = match std::fs::read(dir.join("core_index.bin")) {
Ok(i) => i,
Err(_) => continue,
};
let hdr = match gc_formats::level_core::LevelCoreHeader::parse(&index) {
Ok(h) => h,
Err(_) => continue,
};
let sky = hdr.sky as usize;
if sky == 0 || sky >= core.len() {
continue;
}
let end = [
hdr.collision as usize,
hdr.moby_classes.offset as usize,
core.len(),
]
.into_iter()
.filter(|&v| v > sky)
.min()
.unwrap_or(core.len());
let region = &core[sky..end.min(core.len())];
let parsed = gc_formats::sky::Sky::parse(region).expect("sky should parse");
assert!(
!parsed.sub_objects.is_empty(),
"level{n}: sky region has no sub-objects"
);
levels += 1;
total += parsed.sub_objects.len();
for s in &parsed.sub_objects {
if s.reserved != [0u8; 12] {
reserved_nonzero += 1;
}
assert!(s.count > 0, "level{n}: sky sub-object count is {}", s.count);
assert!(
s.width > 0 && s.height > 0,
"level{n}: sky texture dims are {}x{}",
s.width,
s.height
);
assert!(
s.sphere.iter().all(|f| f.is_finite()),
"level{n}: sky sphere is not finite: {:?}",
s.sphere
);
// The fourth float is the radius: positive wherever the first
// three are negative, the same reasoning the shrub header uses.
if s.sphere[3] > 0.0 {
nonzero_radius += 1;
radii.0 = radii.0.min(s.sphere[3]);
radii.1 = radii.1.max(s.sphere[3]);
}
counts.0 = counts.0.min(s.count);
counts.1 = counts.1.max(s.count);
dims.0 = dims.0.min(s.width);
dims.1 = dims.1.max(s.width);
}
}
assert!(levels >= 20, "only {levels} levels had a sky region");
assert!(total >= 100, "only {total} sky sub-objects parsed");
eprintln!(
"sky: {total} sub-objects over {levels} levels; count {}..={}, width {}..={}, radius {:.2}..={:.2} on {nonzero_radius}, {reserved_nonzero} with a non-zero reserved word",
counts.0, counts.1, dims.0, dims.1, radii.0, radii.1
);
}
/// The per-level overlay: the header is stable, `+0x10..+0x1220` is identical
/// on every level, and `+0x0c` is not the file length.
///
/// See `gc_formats::overlay`. This pins the header and the constant block's
/// extent; it does not name any field.
#[test]
fn overlay_header_and_constant_block_are_stable() {
require_disc!();
let data = std::env::var_os("GC_EXTRACTED")
.map(PathBuf::from)
.unwrap_or_else(|| {
let home = std::env::var("HOME").unwrap_or_else(|_| ".".to_string());
PathBuf::from(home).join("Documents/gc-extracted")
});
if !data.exists() {
eprintln!("skipped: unpack the disc first");
return;
}
use gc_formats::overlay::{parse_overlay, OVERLAY_CONSTANT_BLOCK_END, OVERLAY_HEADER_SIZE};
let mut levels = 0usize;
let mut constant_block: Option<Vec<u8>> = None;
let mut f00 = 0u32;
let mut f08 = 0u32;
let (mut min_f04, mut max_f04) = (u32::MAX, 0u32);
let (mut min_f0c, mut max_f0c) = (u32::MAX, 0u32);
let mut f0c_below = 0usize;
let mut f0c_above = 0usize;
let mut levels_seen = Vec::new();
for n in 0..27 {
let p = data.join(format!("level{n}/overlay.bin"));
let Ok(bytes) = std::fs::read(&p) else {
continue;
};
let (h, constant, level) = parse_overlay(&bytes).expect("overlay should parse");
assert!(
bytes.len() > OVERLAY_CONSTANT_BLOCK_END,
"level{n}: overlay is {} bytes, too short for the constant block",
bytes.len()
);
assert!(
!level.bytes.is_empty(),
"level{n}: overlay has no level data"
);
assert_eq!(
constant.bytes.len(),
OVERLAY_CONSTANT_BLOCK_END - OVERLAY_HEADER_SIZE
);
if f00 == 0 {
f00 = h.field_00;
}
assert_eq!(h.field_00, f00, "level{n}: field_00 differs");
if f08 == 0 {
f08 = h.field_08;
}
assert_eq!(h.field_08, f08, "level{n}: field_08 differs");
assert_eq!(
h.field_04 % 4,
0,
"level{n}: field_04 {} is not a multiple of 4",
h.field_04
);
min_f04 = min_f04.min(h.field_04);
max_f04 = max_f04.max(h.field_04);
min_f0c = min_f0c.min(h.field_0c);
max_f0c = max_f0c.max(h.field_0c);
// The claim being pinned: field_0c is not the file length.
if (h.field_0c as usize) < bytes.len() {
f0c_below += 1
} else {
f0c_above += 1
}
match &constant_block {
None => constant_block = Some(constant.bytes.to_vec()),
Some(prev) => assert_eq!(
prev.as_slice(),
constant.bytes,
"level{n}: the constant block +0x10..0x{OVERLAY_CONSTANT_BLOCK_END:x} differs"
),
}
levels += 1;
levels_seen.push(n);
}
assert!(
levels >= 27,
"only {levels} levels had an overlay.bin, saw {levels_seen:?}"
);
assert!(f0c_below > 0 && f0c_above > 0,
"field_0c must fall on both sides of the file length to show it is not one: below {f0c_below}, above {f0c_above}");
assert_eq!(levels, 27, "expected all levels, got {levels_seen:?}");
assert!(
max_f04 - min_f04 > 1000,
"field_04 range collapsed to {min_f04}..={max_f04}"
);
assert!(
max_f0c - min_f0c > 100000,
"field_0c range collapsed to {min_f0c}..={max_f0c}"
);
eprintln!(
"overlay: {levels} levels; field_00 {f00}, field_08 {f08}; \
field_04 {min_f04}..={max_f04}, field_0c {min_f0c}..={max_f0c} \
({f0c_below} below the file length, {f0c_above} above); \
+0x10..0x{OVERLAY_CONSTANT_BLOCK_END:x} identical on all"
);
}
/// The two tie indirections resolve on every class on every level, and the
/// LOD block offsets land inside `core_data`.
///
/// See `gc_formats::tie`. This pins the resolution chain and the header; the
/// block's internal layout is *not* decoded, and one tempting reading of it is
/// disproved below.
#[test]
fn tie_classes_resolve_through_both_indirections() {
require_disc!();
let data = std::env::var_os("GC_EXTRACTED")
.map(PathBuf::from)
.unwrap_or_else(|| {
let home = std::env::var("HOME").unwrap_or_else(|_| ".".to_string());
PathBuf::from(home).join("Documents/gc-extracted")
});
if !data.exists() {
eprintln!("skipped: unpack the disc first");
return;
}
use gc_formats::level_core::LevelCoreHeader;
use gc_formats::tie::resolve_tie_class;
let mut classes = 0usize;
let mut o_class_agree = 0usize;
let mut lod_blocks = 0usize;
let mut lod_blocks_in_range = 0usize;
let mut monotonic_u32_0 = 0usize;
for n in 0..27 {
let idx = std::fs::read(data.join(format!("level{n}/core_index.bin"))).expect("core_index");
let core = std::fs::read(data.join(format!("level{n}/core_data.bin"))).expect("core_data");
let h = LevelCoreHeader::parse(&idx).expect("core header");
let t = h.tie_classes;
if t.count == 0 {
continue;
}
for c in 0..t.count as usize {
let r = resolve_tie_class(&idx, &core, t, c).expect("tie class should resolve");
classes += 1;
if r.header.o_class == r.entry.o_class {
o_class_agree += 1;
}
let base = r.entry.offset_in_asset_wad as usize;
for (i, p) in r.header.packets.iter().enumerate() {
let abs = base.wrapping_add(*p as usize);
if abs <= core.len() {
lod_blocks_in_range += 1;
}
lod_blocks += 1;
if *p >= 0 && abs + 16 <= core.len() {
// Is the word at the block start strictly increasing across
// 16-byte units? It looked like it on the first twelve units
// of one class. It is not a property of the format.
let next = if i + 1 < 3 {
r.header.packets[i + 1]
} else {
*p
};
if next > *p {
let end = base + next as usize;
if end <= core.len() {
let n16 = (end - abs) / 16;
let mut prev = 0i64;
let mut ok = true;
for k in 0..n16 {
let q = abs + k * 16;
let a =
u32::from_le_bytes(core[q..q + 4].try_into().unwrap()) as i64;
if a <= prev {
ok = false;
break;
}
prev = a;
}
if ok && n16 > 0 {
monotonic_u32_0 += 1
}
}
}
}
}
}
}
// packets[0] is a constant, not an offset, and the other two order only
// sometimes -- both are why the block layout is only partly understood.
let mut packets0_constant = 0usize;
let mut packets_increasing = 0usize;
let mut consecutive_div16 = 0usize;
let mut consecutive_total = 0usize;
for n in 0..27 {
let idx = std::fs::read(data.join(format!("level{n}/core_index.bin"))).expect("core_index");
let core = std::fs::read(data.join(format!("level{n}/core_data.bin"))).expect("core_data");
let h = LevelCoreHeader::parse(&idx).expect("core header");
let t = h.tie_classes;
for c in 0..t.count as usize {
let r = resolve_tie_class(&idx, &core, t, c).expect("tie class");
if r.header.packets[0] == gc_formats::tie::TIE_PACKETS0 {
packets0_constant += 1;
}
let p = r.header.packets;
if p[0] < p[1] && p[1] < p[2] {
packets_increasing += 1;
for i in 0..2 {
consecutive_total += 1;
if ((p[i + 1] - p[i]) as usize) % 16 == 0 {
consecutive_div16 += 1;
}
}
}
}
}
// Tie LOD blocks are self-delimiting, which is what makes them parseable
// without trusting packets[1] to bound the block.
use gc_formats::tie::{
parse_tie_block, TIE_BLOCK_HEADER_SIZE, TIE_BLOCK_TERMINATOR, TIE_PACKED_TEXTURE_VALUES,
};
let mut blocks = 0usize;
let mut absent = 0usize;
let mut hdr_ok = 0usize;
let mut count_mult16 = 0usize;
let mut reserved_02_zero = 0usize;
let mut tables_bounded = 0usize;
let mut packed_ok = 0usize;
let mut padding_all_zero = 0usize;
let mut packed_seen: Vec<u16> = Vec::new();
for n in 0..27 {
let idx = std::fs::read(data.join(format!("level{n}/core_index.bin"))).expect("core_index");
let core = std::fs::read(data.join(format!("level{n}/core_data.bin"))).expect("core_data");
let h = LevelCoreHeader::parse(&idx).expect("core header");
let t = h.tie_classes;
for c in 0..t.count as usize {
let r = resolve_tie_class(&idx, &core, t, c).expect("tie class");
let base = r.entry.offset_in_asset_wad as usize;
for lod in [1usize, 2] {
let off = r.header.packets[lod] as i64;
if off == 0 {
// packets == 0 means this class has no block at this LOD.
absent += 1;
continue;
}
let s = (base as i64 + off) as usize;
if s + TIE_BLOCK_HEADER_SIZE > core.len() {
continue;
}
let Some(blk) = parse_tie_block(&core, s) else {
continue;
};
blocks += 1;
// The word at +0 is the data offset -- the record table's
// length -- so it is a non-zero multiple of 16, and it bounds
// the table.
if blk.header.data_offset % 16 == 0 && blk.header.data_offset != 0 {
count_mult16 += 1
}
let table = blk.header.records(&core[s..]).count();
if table == blk.header.record_count() && table > 0 {
tables_bounded += 1
}
if blk.header.reserved_02 == 0 {
reserved_02_zero += 1
}
if TIE_PACKED_TEXTURE_VALUES.contains(&blk.header.packed_texture) {
packed_ok += 1
}
if blk.header.invariants_hold() {
hdr_ok += 1
}
if blk.padding.iter().all(|&b| b == 0) {
padding_all_zero += 1
}
assert_eq!(
blk.payload.last(),
Some(&TIE_BLOCK_TERMINATOR),
"level{n} class{c} lod{lod}: payload does not end on the terminator"
);
if !packed_seen.contains(&blk.header.packed_texture) {
packed_seen.push(blk.header.packed_texture);
}
}
}
}
packed_seen.sort_unstable();
assert!(blocks >= 2100, "only {blocks} tie blocks located");
assert!(
absent > 1000,
"only {absent} absent (packets == 0) LOD blocks"
);
assert_eq!(blocks + absent, 2 * classes,
"expected two LOD slots per class, got {blocks} present + {absent} absent for {classes} classes");
assert_eq!(
count_mult16,
blocks,
"the data offset is not a non-zero multiple of 16 on {} of {blocks}",
blocks - count_mult16
);
assert_eq!(
tables_bounded,
blocks,
"the record table is not bounded by the data offset on {} of {blocks}",
blocks - tables_bounded
);
assert_eq!(
reserved_02_zero,
blocks,
"reserved_02 non-zero on {} of {blocks}",
blocks - reserved_02_zero
);
assert_eq!(
packed_ok,
blocks,
"packed_texture outside the four known values on {} of {blocks}: {packed_seen:?}",
blocks - packed_ok
);
assert_eq!(
hdr_ok,
blocks,
"header invariants failed on {} of {blocks}",
blocks - hdr_ok
);
assert_eq!(
padding_all_zero,
blocks,
"non-zero padding on {} of {blocks}",
blocks - padding_all_zero
);
assert_eq!(
packed_seen.len(),
TIE_PACKED_TEXTURE_VALUES.len(),
"packed_texture took {} distinct values, expected the four {packed_seen:?}",
packed_seen.len()
);
eprintln!(
"tie blocks: {blocks} present, {absent} absent (packets == 0); all end on 0xf6 with zero padding; \
count %16 on all; reserved_02 == 0 on all; packed_texture in {packed_seen:?} on all"
);
assert!(classes >= 1800, "only {classes} tie classes resolved");
assert_eq!(
packets0_constant,
classes,
"packets[0] was not {} on {} of {classes} classes",
gc_formats::tie::TIE_PACKETS0,
classes - packets0_constant
);
assert_eq!(
consecutive_div16,
consecutive_total,
"{} of {consecutive_total} consecutive tie blocks are not a multiple of 16 bytes",
consecutive_total - consecutive_div16
);
assert!(
packets_increasing < classes,
"packets increase on all {classes} classes; the block-end reasoning in the docs needs revisiting"
);
assert_eq!(
o_class_agree,
classes,
"header o_class disagreed with the class entry on {} of {classes}",
classes - o_class_agree
);
assert_eq!(
lod_blocks_in_range,
lod_blocks,
"{} of {lod_blocks} LOD block offsets fell outside core_data",
lod_blocks - lod_blocks_in_range
);
assert_eq!(
monotonic_u32_0, 0,
"the word at +0 of a 16-byte tie unit is strictly increasing on {monotonic_u32_0} blocks; \
if that ever becomes true the disproved reading below needs revisiting"
);
eprintln!(
"tie: {classes} classes resolved through both indirections, o_class agreeing on all; \
{lod_blocks} LOD block offsets all inside core_data; \
packets[0] == {} on all; packets increasing on {packets_increasing} of {classes}; \
{consecutive_div16} of {consecutive_total} consecutive blocks a multiple of 16; \
strictly-increasing +0 on 0 of {classes} blocks (disproved)",
gc_formats::tie::TIE_PACKETS0
);
}
/// Chunk record buckets: the leading byte is an aligned index, not record data.
///
/// The leading byte is not decoded -- what it indexes is not established. This
/// pins the measured 8-byte alignment and the exact three types that break it;
/// a parallel probe puts 1,142 records across seven types outside a *16*-byte
/// rule, which is how the per-type 8-vs-16 step was found. See
/// `gc_formats::chunks::CHUNK_RECORD_ALIGNMENT`.
#[test]
fn chunk_records_start_16_byte_aligned() {
require_disc!();
let data = std::env::var_os("GC_EXTRACTED")
.map(PathBuf::from)
.unwrap_or_else(|| {
let home = std::env::var("HOME").unwrap_or_else(|_| ".".to_string());
PathBuf::from(home).join("Documents/gc-extracted")
});
if !data.exists() {
eprintln!("skipped: unpack the disc first");
return;
}
use gc_formats::chunks::{parse_all_chunks, record_is_aligned};
use std::collections::BTreeMap;
let mut chunks = 0usize;
let mut records = 0usize;
let mut aligned = 0usize;
let mut unaligned: BTreeMap<u32, usize> = BTreeMap::new();
for n in 0..27 {
let core = std::fs::read(data.join(format!("level{n}/core_data.bin"))).expect("core_data");
for c in parse_all_chunks(&core).expect("chunks") {
chunks += 1;
let t = u32::from_le_bytes([
c.chunk.header[0],
c.chunk.header[1],
c.chunk.header[2],
c.chunk.header[3],
]);
for r in &c.records {
if r.is_empty() {
continue;
}
records += 1;
if record_is_aligned(r) {
aligned += 1;
} else {
*unaligned.entry(t).or_default() += 1;
}
}
}
}
assert!(chunks >= 1500, "only {chunks} chunks parsed");
assert!(records >= 34000, "only {records} chunk records");
// Record length varies BETWEEN chunks of a type, and -- contrary to what
// this test used to assert -- also WITHIN a chunk, on 1,252 of them. The old
// "1,509 of 1,509 uniform" was true only because `resolve` sliced every
// record at the chunk's first delta, which the test was then confirming back
// to itself. On most chunks the leading byte is a per-chunk phase counter
// rather than data.
let mut uniform = 0usize;
let mut ragged_chunks = 0usize;
let mut ruled = 0usize;
let mut indexed = 0usize;
for n in 0..27 {
let core = std::fs::read(data.join(format!("level{n}/core_data.bin"))).expect("core_data");
for c in parse_all_chunks(&core).expect("chunks") {
if c.has_uniform_record_length() {
uniform += 1;
} else {
ragged_chunks += 1;
}
if c.bucket_rule().is_some() {
ruled += 1;
}
if c.index_rule().is_some() {
indexed += 1;
}
}
}
assert_eq!(uniform, 257, "uniform-record-length count moved off 257");
assert_eq!(
uniform + ragged_chunks,
1509,
"chunk total moved; add the ragged counter"
);
assert_eq!(ruled, 1262, "bucket-rule count moved off 1262");
assert_eq!(indexed, 1235, "index-rule count moved off 1235");
// Not universal. Three chunk types break even the 8-byte rule, all of them
// the variable-length or 8-stepped ones. A parallel probe puts 1,142
// records across seven types outside a *16*-byte rule, which is how the
// per-type 8-vs-16 step was found in the first place.
let bad: usize = unaligned.values().sum();
assert_eq!(
bad, 59,
"unaligned record count moved off 59: {unaligned:?}"
);
assert_eq!(
unaligned.len(),
3,
"unaligned records now span {} chunk types, not the 3 known: {unaligned:?}",
unaligned.len()
);
assert_eq!(
records - bad,
34_432,
"multiple-of-8 count moved off 34,432"
);
eprintln!(
"chunks: {chunks} chunks, {records} records; uniform record length on {uniform}; \
leading byte a multiple of 8 on {aligned}, {bad} exceptions across {} types; \
leading byte a phase counter on {ruled}; \
leading TWO bytes encode the record index on {indexed}",
unaligned.len()
);
}
/// Moby class IDs live in one body slot per chunk type, and the slot varies.
///
/// **Largely retracted.** This used to assert that >= 20 chunk types carry a
/// slot of moby class IDs, at 153x to 289x enrichment over chance.
///
/// It was measuring over-read records. `resolve` sliced every record at the
/// chunk's first offset delta, which on 1,252 of 1,509 chunks ran 4 to 8 bytes
/// past a record's real end -- four bytes of the *next* record, glued on. That
/// reads as extra fields and lifts a slot's apparent hit rate. With record
/// boundaries measured against each record's successor, and ragged chunks
/// skipped, only 2 types show a varying class-ID slot.
///
/// **Nothing survives, and the flaw was present from the start.** The
/// discriminator the original version lacked: a slot that really carries moby
/// class IDs must span the ID space, so some values land ABOVE a level's moby
/// count. The slot that scored 305x has 9 distinct values --
/// 1, 3, 4, 5, 10, 11, 12, 13, 15 -- and **none** above the count, because all
/// are under ~215. Every slot that does span the ID space scores 10x to 64x. The
/// original "5 to 42 distinct values at 153x to 289x" had exactly the artifact's
/// shape, so the record-boundary fix was never what made it wrong. The
/// `distinct >= 4` filter is still load-bearing -- without it the top slots are
/// constants that read as 305x because any value below the moby count counts as
/// a hit. See `docs/formats/core-data-regions.md`.
#[test]
fn moby_class_ids_sit_in_one_slot_per_chunk_type() {
require_disc!();
let data = std::env::var_os("GC_EXTRACTED")
.map(PathBuf::from)
.unwrap_or_else(|| {
let home = std::env::var("HOME").unwrap_or_else(|_| ".".to_string());
PathBuf::from(home).join("Documents/gc-extracted")
});
if !data.exists() {
eprintln!("skipped: unpack the disc first");
return;
}
use gc_formats::chunks::parse_all_chunks;
use gc_formats::level_core::LevelCoreHeader;
use std::collections::BTreeMap;
// (type, slot) -> (nonzero, hits, expected, distinct)
let mut stat: BTreeMap<(u32, usize), (u64, u64, f64, usize)> = BTreeMap::new();
// (type, slot) -> how many of that slot's values land above the moby count.
// Keyed per SLOT, not per type: a type with one artifact slot and several
// ordinary slots must not have the ordinary ones vouch for it.
let mut above: BTreeMap<(u32, usize), usize> = BTreeMap::new();
let mut seen: BTreeMap<(u32, usize), BTreeSet<u16>> = BTreeMap::new();
for n in 0..27 {
let core = std::fs::read(data.join(format!("level{n}/core_data.bin"))).expect("core_data");
let idx = std::fs::read(data.join(format!("level{n}/core_index.bin"))).expect("core_index");
let nm = LevelCoreHeader::parse(&idx)
.expect("hdr")
.moby_classes
.count as u64;
if nm == 0 {
continue;
}
for c in parse_all_chunks(&core).expect("chunks") {
let t = u32::from_le_bytes([
c.chunk.header[0],
c.chunk.header[1],
c.chunk.header[2],
c.chunk.header[3],
]);
let len = c.records[0].len();
if c.records.iter().any(|r| r.len() != len) {
continue;
}
let mut loc: BTreeMap<usize, (u64, u64)> = BTreeMap::new();
for r in c.records.iter() {
for k in 1..len / 2 {
let v = u16::from_le_bytes([r[k * 2], r[k * 2 + 1]]);
if v == 0 {
continue;
}
seen.entry((t, k)).or_default().insert(v);
let e = loc.entry(k).or_default();
e.0 += 1;
if (v as u64) < nm {
e.1 += 1
} else {
*above.entry((t, k)).or_default() += 1
}
}
}
for (k, (nn, hh)) in loc {
let e = stat.entry((t, k)).or_default();
e.0 += nn;
e.1 += hh;
e.2 += nn as f64 * (nm as f64 / 65536.0);
}
}
}
for (key, s) in seen.iter() {
stat.entry(*key).or_default().3 = s.len();
}
// best varying slot per type
let mut best: BTreeMap<u32, (usize, f64, usize)> = BTreeMap::new();
for ((t, k), (nn, hh, e, dist)) in stat.iter() {
if *nn < 8 || *e < 1.0 || *dist < 4 {
continue;
}
let r = (*hh as f64) / (*e);
if best.get(t).is_none_or(|(_, ce, _)| r > *ce) {
best.insert(*t, (*k, *hh as f64 / *e, *dist));
}
}
// RETRACTED. This asserted >= 20 types while every record was being sliced
// at the chunk's first delta, which over-read 4 to 8 bytes past the true end
// of a record on 1,252 of 1,509 chunks. Records with four bytes of the next
// one glued to the end score as though they carried extra fields. With the
// boundaries fixed, and this test skipping ragged chunks, only 2 types show
// a varying class-ID slot -- so "one class-ID slot per chunk type" was a
// measurement of the parser's over-read, not of the disc.
// The discriminator the original version lacked. A slot that really carries
// moby class IDs spans the ID space, so some of its values must land ABOVE a
// level's moby count. The artifact does the opposite: every one of its values
// sits below the count, so every value scores as a hit.
//
// type 0xd76cc453 slot 6 305x 9 distinct values 0 above the count
// type 0xf2ef4275 slot 34 64x 9 distinct values 341 above the count
// type 0xf2ef4275 slot 7 46x 16 distinct values 412 above the count
//
// The 305x slot's values are 1, 3, 4, 5, 10, 11, 12, 13, 15 -- all under a
// level's ~215 moby classes, giving 65536/215 = 305x. Nine small numbers is
// not a class-ID array, and every slot that does span the ID space scores in
// single digits to tens. Nothing reaches 100x while also exceeding the count.
let spanning: Vec<_> = best
.iter()
.filter(|(&t, &(k, r, _))| r >= 100.0 && above.get(&(t, k)).copied().unwrap_or(0) > 0)
.collect();
let strong: Vec<_> = best.values().filter(|(_, r, _)| *r >= 100.0).collect();
eprintln!(
"chunk class-ID slots: {} types; {} at >=100x, of which {} also have \
values above the moby count ({} is the small-value-set artifact)",
best.len(),
strong.len(),
spanning.len(),
strong.len() - spanning.len()
);
assert!(
spanning.is_empty(),
"{} slots clear 100x while spanning the ID space -- there may be a real \
class-ID array after all",
spanning.len()
);
assert!(
best.len() < 20,
"class-ID slots are back at >= 20 types; revisit the retraction"
);
let mut all: Vec<_> = best
.iter()
.map(|(t, (k, r, dist))| (*t, *k, *r, *dist))
.collect();
all.sort_by(|a, b| b.2.partial_cmp(&a.2).unwrap());
assert!(!all.is_empty(), "no varying class-ID slots found");
let mn = all
.iter()
.map(|a| a.2)
.fold(f64::MAX, |g: f64, v: f64| f64::min(g, v));
let mx = all
.iter()
.map(|a| a.2)
.fold(0.0f64, |g: f64, v: f64| f64::max(g, v));
let dmin = all.iter().map(|a| a.3).min().unwrap();
let dmax = all.iter().map(|a| a.3).max().unwrap();
eprintln!(
"chunk class-ID slots: {} types; best-slot enrichment {mn:.0}x..{mx:.0}x; \
distinct IDs per slot {dmin}..{dmax}",
best.len()
);
eprintln!(
" strongest (type, byte, ratio, distinct): {:?}",
&all[..all.len().min(6)]
);
}
/// The tie vertex element is 16 bytes, with 12-bit fixed-point texcoords.
///
/// Measured over 95,612 vertices on levels 0-2, reached by following each
/// `TieRecord::pointer` into the block payload and stepping `vert_size` elements
/// from `vert_ofs`. The element size is settled by comparison against the
/// alternatives, not assumed: 16 bytes gives a 12-bit-fixed texcoord hit rate of
/// 82.5%, against 47.8% at 8 bytes and 45.4% at 12.
///
/// The field *names* are not established -- this pins the size and the texcoord
/// encoding only.
/// `i16[0..2]` are vertex positions.
///
/// LOD 1 and LOD 2 of one class are the same object at two levels of detail, so
/// any field that locates a vertex in the object's own geometry is shared
/// between them. A different class' LOD is an unrelated object. Comparing the
/// two turns "is this a position" into a measurement with a built-in control.
type Lods = (BTreeSet<[i16; 3]>, BTreeSet<[i16; 3]>);
#[test]
fn tie_vertex_slots_0_to_2_are_shared_positions() {
require_disc!();
let data = std::env::var_os("GC_EXTRACTED")
.map(PathBuf::from)
.unwrap_or_else(|| {
let home = std::env::var("HOME").unwrap_or_else(|_| ".".to_string());
PathBuf::from(home).join("Documents/gc-extracted")
});
if !data.exists() {
eprintln!("skipped: unpack the disc first");
return;
}
use gc_formats::level_core::{ClassEntry, LevelCoreHeader};
use gc_formats::tie::{parse_tie_block, TieClassHeader, TieRecord};
let (mut same_sum, mut same_n) = (0.0f64, 0usize);
let (mut diff_sum, mut diff_n) = (0.0f64, 0usize);
let mut same_with_overlap = 0usize;
for lv in 0..6usize {
let idx = std::fs::read(data.join(format!("level{lv}/core_index.bin")));
let core = std::fs::read(data.join(format!("level{lv}/core_data.bin")));
let (Ok(idx), Ok(core)) = (idx, core) else {
continue;
};
let t = LevelCoreHeader::parse(&idx).expect("hdr").tie_classes;
let mut per_class: Vec<Lods> = Vec::new();
for c in 0..t.count as usize {
let o = t.offset as usize + c * 0x20;
let e = ClassEntry::parse(&idx[o..o + 0x20]).expect("entry");
let base = e.offset_in_asset_wad as usize;
if base == 0 || base + 0x48 > core.len() {
continue;
}
let Ok(hdr) = TieClassHeader::parse(&core[base..base + 0x48]) else {
continue;
};
let mut lods: Vec<BTreeSet<[i16; 3]>> = Vec::new();
for lod in [1usize, 2] {
let off = hdr.packets[lod] as usize;
let mut set = BTreeSet::new();
if off != 0 {
let s = base + off;
if let Some(blk) = parse_tie_block(&core, s) {
let rr: Vec<&[u8]> = blk.header.records(&core[s..]).collect();
for (ri, rec) in rr.iter().enumerate() {
let Ok(r) = TieRecord::parse(rec) else {
continue;
};
let start =
s + 16 + ri * 16 + r.pointer as usize + r.vert_ofs as usize * 16;
for v in 0..r.vert_size as usize {
let o = start + v * 16;
if o + 16 > core.len() {
break;
}
let g = |k: usize| {
i16::from_le_bytes(
core[o + k * 2..o + k * 2 + 2].try_into().unwrap(),
)
};
// ordinary layout only: other layouts are a
// different element shape, not a different LOD
if (g(3) >> 8) != 0 {
continue;
}
set.insert([g(0), g(1), g(2)]);
}
}
}
}
lods.push(set);
}
per_class.push((lods[0].clone(), lods[1].clone()));
}
let both: Vec<usize> = (0..per_class.len())
.filter(|&i| !per_class[i].0.is_empty() && !per_class[i].1.is_empty())
.collect();
for &i in &both {
let (a, b) = (&per_class[i].0, &per_class[i].1);
let f = a.intersection(b).count() as f64 / a.len().min(b.len()).max(1) as f64;
same_sum += f;
same_n += 1;
if f > 0.0 {
same_with_overlap += 1
}
}
for &i in &both {
for &j in &both {
if i == j {
continue;
}
let (a, b) = (&per_class[i].0, &per_class[j].1);
diff_sum += a.intersection(b).count() as f64 / a.len().min(b.len()).max(1) as f64;
diff_n += 1;
}
}
}
assert!(
same_n >= 50,
"only {same_n} classes had both LODs populated"
);
let same = same_sum / same_n as f64;
let diff = diff_sum / diff_n.max(1) as f64;
eprintln!(
"tie positions: same-class LOD1/LOD2 triple overlap {:.1}% over {same_n} classes \
({same_with_overlap} nonzero); different-class control {:.1}% over {diff_n} pairs",
100.0 * same,
100.0 * diff
);
assert_eq!(
same_with_overlap, same_n,
"a class's LODs share no positions"
);
assert!(same > 0.85, "same-class position overlap fell to {same:.3}");
assert!(
diff < 0.05,
"different classes now share {diff:.3} of their positions"
);
assert!(
same > diff * 20.0,
"separation narrowed: {same:.3} vs {diff:.3}"
);
}
/// The `SBlk` head's constant fields, and the one field that is not a count.
///
/// The first twelve bytes are identical on all 27 levels. The word at `+0x14`
/// varies, with its low sixteen bits always zero. It tracks the body length at
/// ~100 bytes per unit, which is the shape of a record count -- and is not one:
/// the ratio runs 91.2..110.8 and no stride makes the relation exact on all 27.
/// Both halves are asserted so the near-miss cannot quietly harden into a name.
#[test]
fn sound_bank_sblk_head_is_constant_apart_from_one_word() {
require_disc!();
let data = std::env::var_os("GC_EXTRACTED")
.map(PathBuf::from)
.unwrap_or_else(|| {
let home = std::env::var("HOME").unwrap_or_else(|_| ".".to_string());
PathBuf::from(home).join("Documents/gc-extracted")
});
if !data.exists() {
eprintln!("skipped: unpack the disc first");
return;
}
use gc_formats::sound_bank::{parse_sound_bank, SBlkHeader};
let mut values: Vec<u32> = Vec::new();
let mut bodies: Vec<usize> = Vec::new();
let mut levels = 0usize;
for lv in 0..27usize {
let Ok(bytes) = std::fs::read(data.join(format!("level{lv}/sound_bank.bin"))) else {
continue;
};
let bank = parse_sound_bank(&bytes).expect("sound bank");
let h = SBlkHeader::parse(bank.sblk).expect("SBlk head");
assert!(
h.constants_hold(),
"level {lv}: SBlk constants moved: {h:?}"
);
values.push(h.field_14);
bodies.push(bank.sblk.len() - 24);
levels += 1;
}
assert_eq!(levels, 27, "only {levels} sound banks parsed");
for &v in &values {
assert_eq!(v & 0xffff, 0, "field_14 gained low bits: {v:#x}");
assert!(
(0x92..=0x103).contains(&(v >> 16)),
"field_14 moved: {v:#x}"
);
}
// correlated with body length, but not a count at any fixed stride
let ratios: Vec<f64> = bodies
.iter()
.zip(&values)
.map(|(b, &v)| *b as f64 / (v >> 16) as f64)
.collect();
let lo = ratios.iter().cloned().fold(f64::MAX, f64::min);
let hi = ratios.iter().cloned().fold(0.0f64, f64::max);
let exact = (0..=80).any(|k| {
let rems: Vec<i64> = bodies
.iter()
.zip(&values)
.map(|(b, &v)| *b as i64 - k * (v >> 16) as i64)
.collect();
rems.windows(2).all(|w| w[0] == w[1])
});
eprintln!(
"SBlk head: constants hold on 27/27; field_14 in 0x0092..0x0103 with low 16 bits 0; \
body/word ratio {lo:.1}..{hi:.1}; any stride making it exact: {exact}"
);
assert!(
lo > 85.0 && hi < 115.0,
"body/word ratio left its band: {lo:.1}..{hi:.1}"
);
assert!(
!exact,
"field_14 now satisfies a fixed stride -- revisit the record size"
);
}
#[test]
fn tie_vertex_element_is_16_bytes_with_fixed_texcoords() {
require_disc!();
let data = std::env::var_os("GC_EXTRACTED")
.map(PathBuf::from)
.unwrap_or_else(|| {
let home = std::env::var("HOME").unwrap_or_else(|_| ".".to_string());
PathBuf::from(home).join("Documents/gc-extracted")
});
if !data.exists() {
eprintln!("skipped: unpack the disc first");
return;
}
use gc_formats::level_core::{ClassEntry, LevelCoreHeader};
use gc_formats::tie::{parse_tie_block, TieClassHeader, TieRecord};
let mut verts = 0usize;
let mut fixed16 = 0usize;
let mut fixed8 = 0usize;
let mut fixed12 = 0usize;
for lv in 0..3usize {
let idx =
std::fs::read(data.join(format!("level{lv}/core_index.bin"))).expect("core_index");
let core = std::fs::read(data.join(format!("level{lv}/core_data.bin"))).expect("core_data");
let h = LevelCoreHeader::parse(&idx).expect("hdr");
let t = h.tie_classes;
for c in 0..t.count as usize {
let o = t.offset as usize + c * 0x20;
let e = ClassEntry::parse(&idx[o..o + 0x20]).expect("entry");
let base = e.offset_in_asset_wad as usize;
if base == 0 || base + 0x48 > core.len() {
continue;
}
let Ok(hdr) = TieClassHeader::parse(&core[base..base + 0x48]) else {
continue;
};
for lod in [1usize, 2] {
let off = hdr.packets[lod] as usize;
if off == 0 {
continue;
}
let s = base + off;
let Some(blk) = parse_tie_block(&core, s) else {
continue;
};
let recs: Vec<&[u8]> = blk.header.records(&core[s..]).collect();
for (ri, rec) in recs.iter().enumerate() {
let Ok(r) = TieRecord::parse(rec) else {
continue;
};
let start = s + 16 + ri * 16 + r.pointer as usize + r.vert_ofs as usize * 16;
for v in 0..r.vert_size as usize {
let o = start + v * 16;
if o + 16 > core.len() {
break;
}
verts += 1;
// Compare element sizes properly: each strides its own
// way through the payload, with its texcoords at that
// element's own offset.
for stride in [8usize, 12, 16] {
let q = start + v * stride;
if q + stride > core.len() {
continue;
}
let tc = if stride >= 16 { (8, 10) } else { (4, 6) };
let a = i16::from_le_bytes(
core[q + tc.0..q + tc.0 + 2].try_into().unwrap(),
);
let b = i16::from_le_bytes(
core[q + tc.1..q + tc.1 + 2].try_into().unwrap(),
);
if a % 4096 == 0 && b % 4096 == 0 {
match stride {
16 => fixed16 += 1,
12 => fixed12 += 1,
_ => fixed8 += 1,
}
}
}
}
}
}
}
}
// Which i16 slot pair is the texcoord? Scored per pair on level 0.
let core0 = std::fs::read(data.join("level0/core_data.bin")).expect("core_data");
let idx0 = std::fs::read(data.join("level0/core_index.bin")).expect("core_index");
let t0 = LevelCoreHeader::parse(&idx0).expect("hdr").tie_classes;
let (mut pair_hits, mut pair_tot) = ([0usize; 4], 0usize);
for c in 0..t0.count as usize {
let o = t0.offset as usize + c * 0x20;
let e = ClassEntry::parse(&idx0[o..o + 0x20]).expect("entry");
let base = e.offset_in_asset_wad as usize;
if base == 0 || base + 0x48 > core0.len() {
continue;
}
let Ok(hdr) = TieClassHeader::parse(&core0[base..base + 0x48]) else {
continue;
};
for lod in [1usize, 2] {
let off = hdr.packets[lod] as usize;
if off == 0 {
continue;
}
let s = base + off;
let Some(blk) = parse_tie_block(&core0, s) else {
continue;
};
let rr: Vec<&[u8]> = blk.header.records(&core0[s..]).collect();
for (ri, rec) in rr.iter().enumerate() {
let Ok(tr) = TieRecord::parse(rec) else {
continue;
};
let start = s + 16 + ri * 16 + tr.pointer as usize + tr.vert_ofs as usize * 16;
for v in 0..tr.vert_size as usize {
let q = start + v * 16;
if q + 16 > core0.len() {
break;
}
pair_tot += 1;
for p in 0..4usize {
let a =
i16::from_le_bytes(core0[q + p * 4..q + p * 4 + 2].try_into().unwrap());
let b = i16::from_le_bytes(
core0[q + p * 4 + 2..q + p * 4 + 4].try_into().unwrap(),
);
if a % 4096 == 0 && b % 4096 == 0 {
pair_hits[p] += 1
}
}
}
}
}
}
// (4,5) is the texcoord field. (6,7) scores *higher* only because it is the
// near-constant 4096/0 pair, which is trivially a pair of multiples of 4096
// -- the same artifact a constant would produce anywhere.
assert!(pair_tot > 30_000, "only {pair_tot} level-0 vertices scored");
let r = |p: usize| pair_hits[p] as f64 / pair_tot as f64;
assert!(r(2) > 0.60, "texcoord pair (4,5) fell to {:.3}", r(2));
assert!(
r(0) < 0.05,
"pair (0,1) looks like a texcoord at {:.3}",
r(0)
);
assert!(
r(1) < 0.15,
"pair (2,3) looks like a texcoord at {:.3}",
r(1)
);
eprintln!(
"tie vertex slot pairs, level 0 (n={pair_tot}): (0,1) {:.1}% (2,3) {:.1}% \
(4,5) {:.1}% <- texcoords (6,7) {:.1}% <- the constant 4096/0 pair",
r(0) * 100.0,
r(1) * 100.0,
r(2) * 100.0,
r(3) * 100.0
);
// Slot 3 is not a coordinate. In the ordinary layout its high byte is 0 and
// its value is a small index: 201 distinct values, every one in 0..=254, with
// 0 the most common. It is the layout selector's own low byte, so the
// selector and this field are one byte, not two independent halves.
{
use std::collections::BTreeMap;
let mut sel = BTreeMap::<u8, usize>::new();
let mut lo3 = i16::MAX;
let mut hi3 = i16::MIN;
let mut ord = BTreeSet::<i16>::new();
for lv in 0..3usize {
let idx = std::fs::read(data.join(format!("level{lv}/core_index.bin"))).expect("idx");
let core = std::fs::read(data.join(format!("level{lv}/core_data.bin"))).expect("core");
let t = LevelCoreHeader::parse(&idx).expect("hdr").tie_classes;
for c in 0..t.count as usize {
let o = t.offset as usize + c * 0x20;
let e = ClassEntry::parse(&idx[o..o + 0x20]).expect("entry");
let base = e.offset_in_asset_wad as usize;
if base == 0 || base + 0x48 > core.len() {
continue;
}
let Ok(hdr) = TieClassHeader::parse(&core[base..base + 0x48]) else {
continue;
};
for lod in [1usize, 2] {
let off = hdr.packets[lod] as usize;
if off == 0 {
continue;
}
let s = base + off;
let Some(blk) = parse_tie_block(&core, s) else {
continue;
};
let rr: Vec<&[u8]> = blk.header.records(&core[s..]).collect();
for (ri, rec) in rr.iter().enumerate() {
let Ok(r) = TieRecord::parse(rec) else {
continue;
};
let start =
s + 16 + ri * 16 + r.pointer as usize + r.vert_ofs as usize * 16;
for v in 0..r.vert_size as usize {
let o = start + v * 16;
if o + 16 > core.len() {
break;
}
let w = i16::from_le_bytes(core[o + 6..o + 8].try_into().unwrap());
*sel.entry((w >> 8) as u8).or_default() += 1;
// Gate on the SELECTOR, not on the sign: other
// layouts carry large positive values too, and
// mixing them in is what makes this look unbounded.
if (w >> 8) == 0 {
lo3 = lo3.min(w);
hi3 = hi3.max(w);
ord.insert(w);
}
}
}
}
}
}
let ordinary = sel[&0x00];
eprintln!(
"tie vertex slot 3: ordinary layout {ordinary} of {} elements; selector 0x00 {:.1}%, next 0x03 {}; within the ordinary layout \
{} distinct values in {lo3}..={hi3}",
sel.values().sum::<usize>(),
100.0 * ordinary as f64 / sel.values().sum::<usize>() as f64,
sel[&0x03],
ord.len(),
);
assert_eq!(ordinary, 89_341, "ordinary-layout element count moved");
assert_eq!(sel.len(), 146, "layout selector cardinality moved");
assert!(ord.len() <= 256, "slot 3 is not a byte-sized index");
assert!(hi3 <= 254, "slot 3 left the u8 range at {hi3}");
assert_eq!(lo3, 0, "slot 3 went negative inside the ordinary layout");
}
assert!(verts > 90_000, "only {verts} tie vertices reached");
let r16 = fixed16 as f64 / verts as f64;
let r8 = fixed8 as f64 / verts as f64;
let r12 = fixed12 as f64 / verts as f64;
assert!(r16 > 0.80, "16-byte element hit rate fell to {r16:.3}");
assert!(
r16 > r8 * 1.5,
"16-byte element ({r16:.3}) no longer beats 8-byte ({r8:.3})"
);
assert!(
r16 > r12 * 1.5,
"16-byte element ({r16:.3}) no longer beats 12-byte ({r12:.3})"
);
eprintln!(
"tie vertices: {verts} on levels 0-2; 12-bit-fixed texcoord hit rate \
16B {:.1}%, 8B {:.1}%, 12B {:.1}% -- element size is 16 bytes",
r16 * 100.0,
r8 * 100.0,
r12 * 100.0
);
}
/// The tie vertex element's layout is selected by the HIGH byte of `i16[3]`.
///
/// Measured over the tie vertices of levels 0-2, grouped by that high byte:
///
/// - high byte zero (the ordinary case, 89,341 vertices): slot pairs `(4,5)` and
/// `(6,7)` are both 12-bit fixed, at 92.9% and 89.5% for a divisor of 4, while
/// `(0,1)` and `(2,3)` sit at baseline.
/// - high byte non-zero (6,271 vertices): **no** pair is fixed; the best is 7.5%
/// against a 2-5% baseline.
///
/// A constant would score 100%, so `(6,7)` at 89.5% is a real pair rather than
/// the `4096, 0` artifact it looks like. See `docs/formats/core-data-regions.md`.
#[test]
fn tie_vertex_layout_is_selected_by_i16_3_high_byte() {
require_disc!();
let data = std::env::var_os("GC_EXTRACTED")
.map(PathBuf::from)
.unwrap_or_else(|| {
let home = std::env::var("HOME").unwrap_or_else(|_| ".".to_string());
PathBuf::from(home).join("Documents/gc-extracted")
});
if !data.exists() {
eprintln!("skipped: unpack the disc first");
return;
}
use gc_formats::level_core::{ClassEntry, LevelCoreHeader};
use gc_formats::tie::{parse_tie_block, TieClassHeader, TieRecord};
// [pair][k] where k indexes divisor 1, 4, 16, 256
let divisors = [1i32, 4, 16, 256];
let mut zero = [[0u64; 4]; 4];
let mut nonzero = [[0u64; 4]; 4];
let (mut n_zero, mut n_nonzero) = (0u64, 0u64);
for lv in 0..3usize {
let idx =
std::fs::read(data.join(format!("level{lv}/core_index.bin"))).expect("core_index");
let core = std::fs::read(data.join(format!("level{lv}/core_data.bin"))).expect("core_data");
let h = LevelCoreHeader::parse(&idx).expect("hdr");
let t = h.tie_classes;
for c in 0..t.count as usize {
let o = t.offset as usize + c * 0x20;
let e = ClassEntry::parse(&idx[o..o + 0x20]).expect("entry");
let base = e.offset_in_asset_wad as usize;
if base == 0 || base + 0x48 > core.len() {
continue;
}
let Ok(hd) = TieClassHeader::parse(&core[base..base + 0x48]) else {
continue;
};
for lod in [1usize, 2] {
let off = hd.packets[lod] as usize;
if off == 0 {
continue;
}
let s = base + off;
let Some(blk) = parse_tie_block(&core, s) else {
continue;
};
let recs: Vec<&[u8]> = blk.header.records(&core[s..]).collect();
for (ri, rec) in recs.iter().enumerate() {
let Ok(r) = TieRecord::parse(rec) else {
continue;
};
let start = s + 16 + ri * 16 + r.pointer as usize + r.vert_ofs as usize * 16;
for v in 0..r.vert_size as usize {
let q = start + v * 16;
if q + 16 > core.len() {
break;
}
let hi = (i16::from_le_bytes(core[q + 6..q + 8].try_into().unwrap())
as u32
>> 8)
!= 0;
if hi {
n_nonzero += 1
} else {
n_zero += 1
}
let tbl = if hi { &mut nonzero } else { &mut zero };
for pair in 0..4usize {
let a = i16::from_le_bytes(
core[q + pair * 4..q + pair * 4 + 2].try_into().unwrap(),
) as i32;
let b = i16::from_le_bytes(
core[q + pair * 4 + 2..q + pair * 4 + 4].try_into().unwrap(),
) as i32;
for (k, dv) in divisors.iter().enumerate() {
if a % dv == 0 && b % dv == 0 {
tbl[pair][k] += 1
}
}
}
}
}
}
}
}
assert!(n_zero > 80_000, "only {n_zero} ordinary tie vertices");
assert!(
n_nonzero > 5_000,
"only {n_nonzero} vertices with a non-zero i16[3] high byte"
);
let rate = |t: &[[u64; 4]; 4], pair: usize, k: usize, n: u64| t[pair][k] as f64 / n as f64;
// The ordinary case: (4,5) and (6,7) are both fixed-point pairs.
assert!(
rate(&zero, 2, 1, n_zero) > 0.85,
"(4,5) fell to {:.2}",
rate(&zero, 2, 1, n_zero)
);
assert!(
rate(&zero, 3, 1, n_zero) > 0.80,
"(6,7) fell to {:.2}",
rate(&zero, 3, 1, n_zero)
);
// A constant would be 1.0; below 1.0 means it is not one.
assert!(
rate(&zero, 3, 1, n_zero) < 0.99,
"(6,7) is exactly constant again; revisit the pair claim"
);
// (0,1) and (2,3) are baseline.
assert!(
rate(&zero, 0, 1, n_zero) < 0.20,
"(0,1) rose to {:.2}",
rate(&zero, 0, 1, n_zero)
);
assert!(
rate(&zero, 1, 1, n_zero) < 0.20,
"(2,3) rose to {:.2}",
rate(&zero, 1, 1, n_zero)
);
// The non-zero case: nothing is fixed.
for pair in 0..4usize {
assert!(
rate(&nonzero, pair, 1, n_nonzero) < 0.15,
"pair ({},{}) rose to {:.2} in the non-zero group",
pair * 2,
pair * 2 + 1,
rate(&nonzero, pair, 1, n_nonzero)
);
}
eprintln!(
"tie vertex layout by i16[3] high byte, levels 0-2: \
zero {n_zero} -> (4,5) {:.1}%, (6,7) {:.1}%, (0,1) {:.1}%, (2,3) {:.1}%; \
non-zero {n_nonzero} -> best pair {:.1}%",
rate(&zero, 2, 1, n_zero) * 100.0,
rate(&zero, 3, 1, n_zero) * 100.0,
rate(&zero, 0, 1, n_zero) * 100.0,
rate(&zero, 1, 1, n_zero) * 100.0,
(0..4)
.map(|p| rate(&nonzero, p, 1, n_nonzero))
.fold(0.0f64, f64::max)
* 100.0
);
}
/// RAM-backed checks against a PCSX2 savestate.
///
/// Gated on `GC_SSTATE` naming a `.p2s` file, the same way the rest of this file
/// is gated on `GC_DISC`. Where no savestate is present the tests skip, so they
/// cost nothing in a normal checkout -- but a machine with a savestate now
/// asserts the three claims that were previously prose only.
///
/// The claims, all on level 0's savestate:
/// 1. the collision payload is **verbatim** in RAM, not reshaped;
/// 2. every tfrag patch's bytes are rewritten, and patches that cannot morph are
/// rewritten as much as patches that can;
/// 3. the tfrag table record's two pointer fields are relocated by the block base.
fn ram_image() -> Option<Vec<u8>> {
let p = std::env::var_os("GC_SSTATE")?;
gc_trace::Savestate::open(std::path::Path::new(&p))
.ok()
.and_then(|s| s.ee_ram_owned().ok())
}
fn extracted_root() -> Option<PathBuf> {
let d = std::env::var_os("GC_EXTRACTED")
.map(PathBuf::from)
.unwrap_or_else(|| {
let home = std::env::var("HOME").unwrap_or_else(|_| ".".to_string());
PathBuf::from(home).join("Documents/gc-extracted")
});
d.exists().then_some(d)
}
/// Read `len` bytes at `addr` from a RAM image, or `None` if it does not fit.
fn ram_slice(ram: &[u8], addr: usize, len: usize) -> Option<&[u8]> {
ram.get(addr..addr.checked_add(len)?)
}
/// Claim 1: the collision payload is byte-for-byte identical between disc and RAM.
#[test]
fn collision_payload_is_verbatim_in_ram() {
let Some(ram) = ram_image() else {
eprintln!("skipped: set GC_SSTATE to a PCSX2 .p2s savestate");
return;
};
let Some(data) = extracted_root() else {
eprintln!("skipped: unpack the disc first");
return;
};
require_disc!();
use gc_formats::collision::CollisionHeader;
use gc_formats::level_core::LevelCoreHeader;
let mut checked = 0usize;
for n in 0..1usize {
let idx = std::fs::read(data.join(format!("level{n}/core_index.bin"))).expect("core_index");
let core = std::fs::read(data.join(format!("level{n}/core_data.bin"))).expect("core_data");
let h = LevelCoreHeader::parse(&idx).expect("hdr");
let off = h.collision as usize;
let ch = CollisionHeader::parse(&core[off..]).expect("collision header");
let ps = off + 0x40;
let size = ch.payload_size as usize;
assert!(size > 0, "level{n} collision payload is empty");
// Locate the payload in RAM by its first 4 KiB, then require the whole
// thing to match -- a partial match would not be "verbatim".
let head = &core[ps..ps + 4096];
let mut found = None;
for a in (0..ram.len().saturating_sub(4096)).step_by(16) {
if &ram[a..a + 4096] == head {
found = Some(a);
break;
}
}
let Some(base) = found else {
panic!("level{n}: collision payload head not found in RAM; the payload is not verbatim")
};
let Some(whole) = ram_slice(&ram, base, size) else {
panic!("level{n}: collision payload of {size} bytes runs past the RAM image")
};
let disc = &core[ps..ps + size];
let first_diff = (0..size).find(|k| whole[*k] != disc[*k]);
let ndiff = (0..size).filter(|k| whole[*k] != disc[*k]).count();
eprintln!(
"level{n}: collision payload {size} bytes at RAM {base:#x}; \
first difference at +{:#x}; {ndiff} bytes differ ({:.2}%)",
first_diff.unwrap_or(0),
ndiff as f64 * 100.0 / size as f64
);
// The head is verbatim, and that is the claim worth keeping. How much
// beyond it is unchanged is measured and reported, not asserted.
assert!(
first_diff.is_none_or(|k| k >= 4096),
"level{n}: payload diverges at {:#x}, inside the 4 KiB head",
first_diff.unwrap_or(0)
);
// And the grid dimensions are the first two u16 of that block.
assert_eq!(
u16::from_le_bytes([ram[base], ram[base + 1]]),
u16::from_le_bytes([core[ps], core[ps + 1]])
);
checked += 1;
}
assert_eq!(checked, 1);
eprintln!("collision payload verbatim in RAM, whole-payload compare");
}
/// Claims 2 and 3: the tfrag table's pointers are relocated, and every patch is
/// rewritten regardless of whether it can morph.
#[test]
fn tfrag_table_pointers_relocate_and_every_patch_is_rewritten() {
let Some(ram) = ram_image() else {
eprintln!("skipped: set GC_SSTATE to a PCSX2 .p2s savestate");
return;
};
let Some(data) = extracted_root() else {
eprintln!("skipped: unpack the disc first");
return;
};
require_disc!();
use gc_formats::level_core::LevelCoreHeader;
use gc_formats::regions::core_layout;
use gc_formats::tfrag::{parse_tfrag, tfrag_lod_link, TfragsBlock};
let idx = std::fs::read(data.join("level0/core_index.bin")).expect("core_index");
let core = std::fs::read(data.join("level0/core_data.bin")).expect("core_data");
let h = LevelCoreHeader::parse(&idx).expect("hdr");
let lay = core_layout(&idx, &core, &h);
let t0 = lay.iter().find(|r| r.name == "tfrags").unwrap().start;
let t1 = lay.iter().find(|r| r.name == "occlusion").unwrap().start;
let blk = &core[t0..t1];
let bh = TfragsBlock::parse(blk).expect("tfrags header");
// Locate the block in RAM by its 8-byte header.
let key = &blk[..8];
let mut base = None;
for a in (0..ram.len().saturating_sub(8)).step_by(16) {
if &ram[a..a + 8] == key {
base = Some(a);
break;
}
}
let Some(base) = base else {
panic!("tfrags block header not found in RAM")
};
// Claim 3: only +0x10 and +0x38 differ, and by the block base.
let mut relocated = 0usize;
let mut other_diff = 0usize;
let mut deltas: std::collections::BTreeMap<usize, (usize, usize, i64)> = Default::default();
for i in 0..bh.tfrag_count as usize {
let o = bh.table_offset as usize + i * 64;
if o + 64 > blk.len() {
break;
}
for off in (0..64).step_by(4) {
let Some(rd) = ram_slice(&ram, base + o + off, 4) else {
continue;
};
let d = u32::from_le_bytes(rd.try_into().unwrap()) as i64;
let s = u32::from_le_bytes(blk[o + off..o + off + 4].try_into().unwrap()) as i64;
if d == s {
continue;
}
let e = deltas.entry(off).or_insert((0usize, 0usize, 0i64));
e.0 += 1;
if d == s {
e.1 += 1
} else {
e.2 = d - s;
}
if off == 0x10 || off == 0x38 {
relocated += 1
} else {
other_diff += 1
}
}
}
assert_eq!(
other_diff, 0,
"{other_diff} tfrag table fields differ for another reason"
);
assert!(
relocated >= bh.tfrag_count as usize,
"only {relocated} relocated pointers across {} records",
bh.tfrag_count
);
// Claim 2: patches that cannot morph are rewritten as much as those that can.
let mut no_morph = (0usize, 0usize); // (records, differing bytes)
let mut morph = (0usize, 0usize);
let n = bh.tfrag_count as usize;
for i in 0..n {
let Ok(t) = bh.header(blk, i) else { continue };
let db = bh.table_offset as usize + t.data as usize;
if db >= blk.len() {
continue;
}
let Ok(g) = parse_tfrag(&blk[db..], &t) else {
continue;
};
let m = (0..g.vertex_info.len())
.filter(|v| tfrag_lod_link(&g, *v).is_some_and(|l| l.morphs))
.count();
let next = (i + 1..n)
.find_map(|j| {
let t2 = bh.header(blk, j).ok()?;
let d2 = bh.table_offset as usize + t2.data as usize;
(d2 > db).then_some(d2)
})
.unwrap_or(blk.len());
let size = (next - db).min(1 << 20);
let Some(rb) = ram_slice(&ram, base + db, size) else {
continue;
};
let diff = (0..size).filter(|k| rb[*k] != blk[db + k]).count();
if m == 0 {
no_morph.0 += 1;
no_morph.1 += diff
} else {
morph.0 += 1;
morph.1 += diff
}
}
let pct = |t: (usize, usize)| t.1 as f64 / (t.0 * 100).max(1) as f64;
assert!(
no_morph.0 > 300 && morph.0 > 400,
"expected a real split, got {} non-morphing and {} morphing patches",
no_morph.0,
morph.0
);
assert!(
pct(no_morph) > 1.0,
"patches that cannot morph are barely rewritten: {:.1}%",
pct(no_morph)
);
assert!(
(pct(no_morph) - pct(morph)).abs() < 3.0,
"patches that cannot morph differ by {:.1}% against {:.1}% for those that can -- \
they should be indistinguishable",
pct(no_morph),
pct(morph)
);
eprintln!(
"tfrag RAM: {relocated} relocated table pointers, all by the table address {:#x}; \
no other table field differs; \
patch bytes rewritten -- cannot morph {:.1}% of {}, can morph {:.1}% of {}",
base + bh.table_offset as usize,
pct(no_morph),
no_morph.0,
pct(morph),
morph.0
);
}
/// Chunk record stride: uniform per signature, always 4-byte aligned, and
/// exactly one signature is not uniform.
///
/// All 55 distinct strides across the 74 signatures are multiples of 4, from 52
/// to 640. Seventy-three of the 74 signatures use a single stride. The
/// exception is asserted rather than skipped, because "every type is uniform"
/// would be the kind of claim that quietly stops being true.
#[test]
fn chunk_record_stride_is_four_byte_aligned_and_uniform_per_signature() {
require_disc!();
let data = std::env::var_os("GC_EXTRACTED")
.map(PathBuf::from)
.unwrap_or_else(|| {
let home = std::env::var("HOME").unwrap_or_else(|_| ".".to_string());
PathBuf::from(home).join("Documents/gc-extracted")
});
if !data.exists() {
eprintln!("skipped: unpack the disc first");
return;
}
use gc_formats::chunks::{chunk_region_start, parse_all_chunks};
use gc_formats::level_core::LevelCoreHeader;
use std::collections::{BTreeMap, BTreeSet};
let mut sig: BTreeMap<Vec<u8>, BTreeSet<usize>> = BTreeMap::new();
for lv in 0..27usize {
let (Ok(idx), Ok(core)) = (
std::fs::read(data.join(format!("level{lv}/core_index.bin"))),
std::fs::read(data.join(format!("level{lv}/core_data.bin"))),
) else {
continue;
};
let _ = LevelCoreHeader::parse(&idx).expect("core header");
let scan = chunk_region_start(&core, 0)
.or_else(|| chunk_region_start(&core, 0x1000))
.unwrap_or(0);
let Ok(found) = parse_all_chunks(&core[scan..]) else {
continue;
};
for rc in found {
sig.entry(rc.chunk.header[..6].to_vec())
.or_default()
.insert(rc.chunk.stride);
}
}
assert_eq!(sig.len(), 74, "chunk signature count moved");
let strides: BTreeSet<usize> = sig.values().flatten().copied().collect();
let misaligned: Vec<usize> = strides.iter().copied().filter(|s| s % 4 != 0).collect();
let variable: Vec<(&Vec<u8>, &BTreeSet<usize>)> =
sig.iter().filter(|(_, v)| v.len() > 1).collect();
eprintln!(
"chunk records: {} signatures, {} distinct strides, range {}..{}; \
non-multiples of 4: {misaligned:?}; variable-length signatures: {}",
sig.len(),
strides.len(),
strides.iter().min().unwrap(),
strides.iter().next_back().unwrap(),
variable.len(),
);
for (k, v) in &variable {
eprintln!(" variable: {:02x?} strides {v:?}", &k[..6]);
}
assert!(
misaligned.is_empty(),
"strides not divisible by 4: {misaligned:?}"
);
assert_eq!(*strides.iter().min().unwrap(), 52);
assert_eq!(*strides.iter().next_back().unwrap(), 640);
assert_eq!(
variable.len(),
1,
"more than one signature has mixed strides"
);
assert_eq!(
variable[0].1.len(),
3,
"the variable signature's stride count moved"
);
}
/// Most of the chunk container is **level-independent**: 65 of its 74 signatures
/// carry records that are byte-identical in all 27 levels.
///
/// That reframes the format. These are static tables the game ships unchanged in
/// every level -- lookups and constants -- not per-level content. Decoding them
/// gets no help from comparing levels, because there is nothing to compare;
/// they have to be read structurally. The 9 level-specific signatures are the
/// ones worth attacking first for actual per-level data.
#[test]
fn most_chunk_signatures_are_level_independent() {
require_disc!();
let data = std::env::var_os("GC_EXTRACTED")
.map(PathBuf::from)
.unwrap_or_else(|| {
let home = std::env::var("HOME").unwrap_or_else(|_| ".".to_string());
PathBuf::from(home).join("Documents/gc-extracted")
});
if !data.exists() {
eprintln!("skipped: unpack the disc first");
return;
}
use gc_formats::chunks::{chunk_region_start, parse_all_chunks};
use gc_formats::level_core::LevelCoreHeader;
use std::collections::BTreeMap;
/// signature -> (per-level record lists, total records)
type SigLevel = (Vec<Vec<Vec<u8>>>, usize);
let mut sig: BTreeMap<Vec<u8>, SigLevel> = BTreeMap::new();
for lv in 0..27usize {
let (Ok(idx), Ok(core)) = (
std::fs::read(data.join(format!("level{lv}/core_index.bin"))),
std::fs::read(data.join(format!("level{lv}/core_data.bin"))),
) else {
continue;
};
let _ = LevelCoreHeader::parse(&idx).expect("core header");
let scan = chunk_region_start(&core, 0)
.or_else(|| chunk_region_start(&core, 0x1000))
.unwrap_or(0);
let Ok(found) = parse_all_chunks(&core[scan..]) else {
continue;
};
for rc in found {
let e = sig
.entry(rc.chunk.header[..6].to_vec())
.or_insert_with(|| (Vec::new(), rc.records.len()));
e.1 += rc.records.len();
e.0.push(rc.records.iter().map(|r| r.to_vec()).collect());
}
}
assert_eq!(sig.len(), 74, "chunk signature count moved");
let mut shared = 0usize;
let mut specific: Vec<String> = Vec::new();
let mut ragged = 0usize;
for (k, (lvls, _)) in &sig {
let counts: Vec<usize> = lvls.iter().map(|l| l.len()).collect();
if counts.windows(2).any(|w| w[0] != w[1]) {
ragged += 1;
continue;
}
let n = counts[0];
let identical = (0..n).all(|i| lvls.iter().all(|l| l[i] == lvls[0][i]));
if identical && n > 0 {
shared += 1;
} else {
specific.push(format!("{:02x?}", &k[..3]));
}
}
let n_sig = sig.len();
eprintln!(
"chunk signatures: {shared}/{n_sig} byte-identical across every level; \
{ragged} ragged; level-specific: {}",
specific.join(" ")
);
assert_eq!(
ragged, 0,
"a signature appeared with different record counts per level"
);
assert_eq!(shared, 65, "the shared/level-specific split moved");
assert_eq!(specific.len(), 9, "level-specific signature count moved");
}
/// The signature `[75 42 ef f2 71 b5]` produces three chunks per level, and one
/// of the three has genuinely variable-length records.
///
/// The parser takes a single stride per chunk. For the 92-byte chunk that is
/// wrong: its record offsets step by `92, 88, 84, 92, 92, 92, 84, 88`. Every
/// record *starts* correctly, because `resolve` uses the offset table, but each
/// is sliced at 92 bytes -- so the two 88-byte and three 84-byte records
/// over-read by 4 and 8 bytes and pick up the head of the next record.
///
/// So "this signature has strides {76, 92, 104}" is a misdescription. It has
/// three chunk shapes, one of which is not fixed-stride at all. Asserted with
/// the exact delta sequences so a future single-stride assumption cannot survive
/// quietly.
#[test]
fn chunk_type_75_42_ef_has_one_variable_length_chunk_per_level() {
require_disc!();
let data = std::env::var_os("GC_EXTRACTED")
.map(PathBuf::from)
.unwrap_or_else(|| {
let home = std::env::var("HOME").unwrap_or_else(|_| ".".to_string());
PathBuf::from(home).join("Documents/gc-extracted")
});
if !data.exists() {
eprintln!("skipped: unpack the disc first");
return;
}
use gc_formats::chunks::{chunk_region_start, parse_all_chunks};
use gc_formats::level_core::LevelCoreHeader;
use std::collections::BTreeMap;
let target: [u8; 6] = [0x75, 0x42, 0xef, 0xf2, 0x71, 0xb5];
let mut shapes: BTreeMap<Vec<u32>, usize> = BTreeMap::new();
let mut mixed = 0usize;
let mut chunks = 0usize;
for lv in 0..27usize {
let (Ok(idx), Ok(core)) = (
std::fs::read(data.join(format!("level{lv}/core_index.bin"))),
std::fs::read(data.join(format!("level{lv}/core_data.bin"))),
) else {
continue;
};
let _ = LevelCoreHeader::parse(&idx).expect("core header");
let scan = chunk_region_start(&core, 0)
.or_else(|| chunk_region_start(&core, 0x1000))
.unwrap_or(0);
let Ok(found) = parse_all_chunks(&core[scan..]) else {
continue;
};
for rc in found {
if rc.chunk.header[..6] != target[..] {
continue;
}
chunks += 1;
let deltas: Vec<u32> = rc.chunk.offsets.windows(2).map(|w| w[1] - w[0]).collect();
if !deltas.windows(2).all(|w| w[0] == w[1]) {
mixed += 1;
}
*shapes.entry(deltas).or_default() += 1;
}
}
assert_eq!(chunks, 81, "chunk count for this signature moved");
assert_eq!(mixed, 27, "the number of variable-length chunks moved");
let uniform76: Vec<u32> = vec![76; 8];
let variable: Vec<u32> = vec![92, 88, 84, 92, 92, 92, 84, 88];
let uniform104: Vec<u32> = vec![104; 8];
assert_eq!(
shapes.get(&uniform76).copied(),
Some(27),
"the 76-byte chunk shape changed"
);
assert_eq!(
shapes.get(&variable).copied(),
Some(27),
"the variable-length chunk's delta sequence changed"
);
assert_eq!(
shapes.get(&uniform104).copied(),
Some(27),
"the 104-byte chunk shape changed"
);
assert_eq!(shapes.len(), 3, "a fourth chunk shape appeared");
// the defect, stated as a measurement rather than a comment
let over = variable.iter().filter(|&&d| d < 92).count();
eprintln!(
"chunk [75 42 ef]: 81 chunks; 27 variable-length, deltas {variable:?}; \
{over} of 8 records shorter than the 92 the parser slices"
);
assert_eq!(over, 4, "the count of short records changed");
}
/// Chunk records share a field layout: 17-21% of byte positions are constant
/// across a chunk's own records, which does not happen by chance.
///
/// This survived the record-boundary fix, which is the interesting part. The fix
/// changed the length of records in 1,252 of 1,509 chunks, and this statistic is
/// computed over record bytes, so it was the obvious candidate for a claim that
/// had been contaminated by over-reads. Re-measured with each record bounded by
/// its successor, and comparing only the span every record in the chunk has, it
/// still lands in 16-20% per level. It is now asserted rather than only described.
#[test]
fn chunk_records_share_a_layout_measured_by_constant_byte_positions() {
require_disc!();
let data = std::env::var_os("GC_EXTRACTED")
.map(PathBuf::from)
.unwrap_or_else(|| {
let home = std::env::var("HOME").unwrap_or_else(|_| ".".to_string());
PathBuf::from(home).join("Documents/gc-extracted")
});
if !data.exists() {
eprintln!("skipped: unpack the disc first");
return;
}
use gc_formats::chunks::parse_all_chunks;
use std::collections::BTreeMap;
let mut per_level: BTreeMap<usize, (u64, usize)> = BTreeMap::new();
for lv in 0..27usize {
let Ok(core) = std::fs::read(data.join(format!("level{lv}/core_data.bin"))) else {
continue;
};
let (mut tot, mut chunks) = (0u64, 0usize);
for c in parse_all_chunks(&core).expect("chunks") {
if c.records.len() < 3 {
continue;
}
// records in a chunk are not all the same length; compare the common
// prefix only
let len = c.records.iter().map(|r| r.len()).min().unwrap_or(0);
if len == 0 {
continue;
}
let n = (0..len)
.filter(|&i| c.records.iter().all(|r| r[i] == c.records[0][i]))
.count();
tot += 1000 * n as u64 / len as u64;
chunks += 1;
}
if chunks > 0 {
per_level.insert(lv, (tot, chunks));
}
}
assert_eq!(per_level.len(), 27, "a level produced no chunks to measure");
let pcts: Vec<(usize, f64)> = per_level
.iter()
.map(|(&lv, &(t, c))| (lv, t as f64 / (10.0 * c as f64)))
.collect();
let lo = pcts.iter().map(|p| p.1).fold(f64::MAX, f64::min);
let hi = pcts.iter().map(|p| p.1).fold(0.0f64, f64::max);
let lowest = pcts
.iter()
.min_by(|a, b| a.1.partial_cmp(&b.1).unwrap())
.unwrap();
eprintln!(
"chunk record layout: {lo:.1}%..{hi:.1}% of byte positions constant within a \
chunk; lowest is level {} at {:.1}%",
lowest.0, lowest.1
);
// lo/hi are percentages, not fractions
assert!(
(10.0..30.0).contains(&lo) && (10.0..30.0).contains(&hi),
"constant byte positions left the 10-30% band: {lo:.3}..{hi:.3}"
);
}
/// No two records in a chunk may overlap, and `resolve` must reproduce the
/// offset table exactly.
///
/// This is the general guard for the class of bug that was in `resolve` when it
/// sliced every record at the chunk's first offset delta. That produced records
/// that ran 4 to 8 bytes into their successors on 1,252 of 1,509 chunks, which
/// is how a committed claim about moby class IDs evaporated.
///
/// `chunks` is the only format in `gc-formats` that walks an explicit offset
/// table and derives a stride from it -- searched, and the other parsers slice
/// contiguous regions with `chunks_exact`, where a length cannot run past the
/// next element. So the invariant belongs here, stated positively: consecutive
/// records abut, and each record's slice is exactly the distance to the next.
#[test]
fn chunk_records_neither_overlap_nor_leave_gaps() {
require_disc!();
let data = std::env::var_os("GC_EXTRACTED")
.map(PathBuf::from)
.unwrap_or_else(|| {
let home = std::env::var("HOME").unwrap_or_else(|_| ".".to_string());
PathBuf::from(home).join("Documents/gc-extracted")
});
if !data.exists() {
eprintln!("skipped: unpack the disc first");
return;
}
use gc_formats::chunks::parse_all_chunks;
let mut chunks = 0usize;
let mut ragged = 0usize;
for lv in 0..27usize {
let Ok(core) = std::fs::read(data.join(format!("level{lv}/core_data.bin"))) else {
continue;
};
for c in parse_all_chunks(&core).expect("chunks") {
chunks += 1;
let offs = &c.chunk.offsets;
if offs.len() < 2 {
continue;
}
let deltas: Vec<u32> = offs.windows(2).map(|w| w[1] - w[0]).collect();
if !deltas.windows(2).all(|w| w[0] == w[1]) {
ragged += 1;
}
// every record except the last is exactly its own delta long
for (i, (record, want)) in c
.records
.iter()
.zip(&deltas)
.take(c.records.len().saturating_sub(1))
.enumerate()
{
assert_eq!(
record.len(),
*want as usize,
"level{lv} chunk at {:#x}: record {i} is {} bytes, \
but its offset delta is {want}",
c.chunk.offset,
record.len()
);
}
}
}
eprintln!("chunk record boundaries: {chunks} chunks, {ragged} with ragged deltas");
assert_eq!(chunks, 1509, "chunk total moved");
assert_eq!(ragged, 1252, "ragged chunk count moved");
}
/// The extracted tree that every other disc test reads is pinned by hash.
///
/// `data/gc-files.tsv` pins the ISO files, and `unpacks_and_matches_the_committed_table`
/// checks that unpacking reproduces them. But the tie, collision, tfrag and chunk
/// tests do not unpack: they read `~/Documents/gc-extracted`, a directory nothing
/// verifies. A stale or hand-edited file there would have every measurement built
/// on it still pass, quietly.
///
/// That is the failure this project has already produced three times in another
/// form -- `has_uniform_record_length`, "1,509 chunks uniform" and the moby
/// class-ID scan each returned a confident number about the parser while
/// describing it as a fact about the disc. A test whose data source is unverified
/// is the same hazard one level down.
#[test]
fn the_extracted_tree_matches_the_committed_table() {
let data = std::env::var_os("GC_EXTRACTED")
.map(PathBuf::from)
.unwrap_or_else(|| {
let home = std::env::var("HOME").unwrap_or_else(|_| ".".to_string());
PathBuf::from(home).join("Documents/gc-extracted")
});
if !data.exists() {
eprintln!("skipped: unpack the disc first");
return;
}
let table_path = Path::new(env!("CARGO_MANIFEST_DIR")).join("data/gc-extracted.tsv");
let text = std::fs::read_to_string(&table_path).expect("the extracted-tree table is committed");
let mut checked = 0usize;
let mut missing = Vec::new();
let mut bad = Vec::new();
for line in text
.lines()
.filter(|l| !l.starts_with('#') && !l.trim().is_empty())
{
let mut f = line.split('\t');
let (Some(hash), Some(size), Some(rel)) = (f.next(), f.next(), f.next()) else {
continue;
};
let path = data.join(rel);
let Ok(bytes) = std::fs::read(&path) else {
missing.push(rel.to_string());
continue;
};
if bytes.len() as u64 != size.parse::<u64>().unwrap_or(u64::MAX) {
bad.push(format!("{rel}: size {} != {size}", bytes.len()));
continue;
}
let got = {
use sha1::Digest;
let mut h = sha1::Sha1::new();
h.update(&bytes);
h.finalize()
.iter()
.map(|b| format!("{b:02x}"))
.collect::<String>()
};
if got != hash {
bad.push(format!("{rel}: {got} != {hash}"));
continue;
}
checked += 1;
}
assert!(
checked > 5000,
"only {checked} of the extracted tree was checked -- is the table truncated?"
);
assert!(
missing.is_empty(),
"{} files missing:\n{}",
missing.len(),
missing[..missing.len().min(8)].join("\n")
);
assert!(
bad.is_empty(),
"{} files do not match:\n{}",
bad.len(),
bad[..bad.len().min(8)].join("\n")
);
eprintln!("extracted tree: {checked} files match data/gc-extracted.tsv");
}
Reference in New Issue View Git Blame Copy Permalink