Sylpheed/docs/re/BACKLOG.md

RE backlog

Open items that are not being worked right now. Each entry says what is wrong or unknown, what evidence exists, and what the first step would be. Move an item into INDEX.md (with a structures/…md or a parser + test) once it is actually settled.

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✅ SOLVED (2026-08-19) — the paint order is a runtime child list, not a table in the file

The screen object the game builds at load time holds two lists of its elements: the declaration-ordered array at +0x08, and a reordered child array at +0x30 — and the second is the paint order. Read live off the title screen and checked against the draw capture: the seven nameable elements sit at child slots 0, 6, 7, 13, 16, 17, 22, strictly ascending, in exactly the captured order. See structures/ui-screen-runtime.md.

Landed rather than left open (2026-08-19): the compositor now paints in the measured order for the two builds that have been read off the running game (the title build and the GAME ARTS/SETA/anima splash) and falls back to declaration order elsewhere. Rendering that exposed a second defect the same capture settles — kind = 0x4 elements are motion-trail ghosts, absent at rest — and the title now composites correctly (captures/title-composited-measured-order.png). Disc-gated test, checked both ways. The Bevy viewer's UI Screens browser calls the same ui_layout::compose, so the fix reaches what a person actually looks at rather than only the CLI's screen render — checked in iso_loader.rs (compose_screen), which also keeps its element table in declaration order, so the per-element visibility toggles still line up.

Derivation found (2026-08-19): the order sorts by the word at +0x08 of the T8aD sprite header — non-decreasing in paint order on both measured screens, with no inversion, and on the splash it explains the whole permutation. See structures/ui-paint-order-key.md.

Wired into the compositor (2026-08-19) and regression-checked. compose sorts by the key for every build except the two whose measured order is hard coded. It reorders 341 of 965 builds, and a disc-gated test asserts every composite's draw list is strictly increasing in (key, declaration index). Against the two screens the corpus had already verified against the running game — the tutorial PAUSE menu and the title main menu — the new order changes 3.8 % and 1.1 % of pixels, max delta 45/255, with no layout change: only blends where translucent sprites overlap.

Still open:

• 🟡 Which order is more faithful on those two verified screens. The difference is too small to decide against the committed side-by-side oracle and no fresh framebuffer capture of either exists. First thing to check if one is taken.
• ❔ The tie-break. Two groups share a key and the game paints them in an order that is not declaration order; the compositor keeps declaration order there.
• ❔ What the field's bits mean — 0x8000/0x80a0/0xa110 look like flag words with a layer in some bits, not a plain depth. Sorting the whole word works on both measured screens; which bits carry the layer is unknown.
• ❔ A third measured permutation, to promote "holds on two" to a rule. The cheapest is a screen whose object is resident at the same time as the title's.
• ❔ 341 builds now composite in an order no capture has checked.

✅ SOLVED (2026-08-19) — _eff glows were being dropped as focused states

compose skips focused-state records, and the flag matched a trailing f in the name. _eff — this UI's word for a glow layer — ends in one. 2 458 elements matched; 54 have the base element they would be the focused version of, and the other 2 404 across 864 bundles are glows. Requiring the pair recovers 587 of them in composable builds; GP_OPTIONS went from two floating brackets to an actual window. The opt link was tried as a replacement and refuted — 221 targets, 2 suffix-matches, and the targets include pjnet_bg.rat. See structures/ui-focus-and-effect-elements.md.

✅ SOLVED (2026-08-19) — the developer-logo splash can be rendered

is_build required a .rat layout child; the splash has none (its elements name their sprites directly). New is_composable + opt-in --all on the screen commands. The splash draws 6/7 elements, glows first, in the order measured off the running game — so the second of the two measured paint orders is now checkable instead of merely recorded. See structures/ui-composable-bundles.md.

Opened by those two:

• ✅ .prm primitives are decoded (2026-08-19). Untextured full-screen colour quads: 0 of 369 has a payload child, kind & 0x10 ⟺ .prm with zero exceptions in either direction, 361/369 are exactly 1280×720 at 100 % in the corner, and the fill colour is the keyframe's fade ARGB — mostly black at some alpha, i.e. the fade-to-black / dim / flash layers. See structures/ui-prm-primitives.md. Still not composited, for the reason below.

• ✅ Element::rest() fixed (2026-08-19): the resting pose is the hold — the longest run of consecutive keyframes with an identical pose — not the longest gap. A keyframe is the start of a ramp toward the next one, so a long gap means the screen spends it arriving at the far end. Verified against the title framebuffer capture by edge correlation: plateau 0.4597 at shift (0,0), old rule 0.1511 and only after a (+3,+8) shift. Fixes six title elements that rested invisible and the fade quad that rested opaque black. See structures/ui-resting-pose.md and tools/re-capture/align_to_capture.py.

• ✅ The keyframe fade alpha is applied (2026-08-19). ARGB, multiplied on top of tint. Title composite vs the running-game capture: 0.4597 → 0.9538 edge correlation at zero shift. No-op on 4 060 of 5 200 sprite elements, hides 687 transient HUD indicators, blanks zero builds. It also exposed a defect in the resting rule — a keyframe group carries the screen's exit animation too, and the tie-break was grabbing it, which erased the word PAUSE; a run ending on the last keyframe is now excluded. See structures/ui-resting-pose.md.

• 🟡 The .prm quads are drawn, opt-in (2026-08-19). ComposeOptions::include_primitives / screen render --primitives. On the title — the one screen with ground truth — it takes mean luminance from +18 % to −1.3 % of the capture (76.30 → 63.72 vs 64.58) and mean abs diff 16.07 → 13.08. Off by default because of the item below.

• 🟡 Where a primitive paints — not in the file; measured and tabled (2026-08-19). 🔴 Refuted twice over: the declaration entry's four unread words are constant (+28=0, +36=0xffffffff, +56=0, +44 a button ordinal), and the bundle carries no data at all for a primitive — the menu build declares three and has zero RATC children for any of them. The layer comes from the game's code. ✅ But it is consistent: pteff02.prm implies a key in (0x8010, 0x8040) on both screens it appears on, pteff00.prm past the maximum on both, palogo_eff0.prm below the minimum. implied_layer_key records those, and derived_paint_order now reproduces the layer-key sequence of all three measured orders, primitives included (element-for- element on 4 of 5 bundle instances; the title differs only inside tied groups). ❔ Still open: primitives whose position has never been measured — pzeff00.prm and pceff00.prm are what wipe the 36 builds, which is why include_primitives stays off by default. A capture of any screen carrying one would close it. See structures/ui-prm-primitives.md.

• 🟡 The tie-break — refuted six ways, and its cost measured (2026-08-19). Elements sharing a layer key: on the menu and splash every tied group comes out in declaration order, which the stable sort already gives. The title is the only screen that discriminates and nothing predicts it (0x8083 ×5 paints eff1, eff2, eff5, eff3, eff4). Refuted: declaration order, RATC child order, first keyframe time, resting time, resting X/Y, and T8aD header words +00 +04 +0c +10. RATC child order is a strict improvement (7 misplaced positions instead of 9, and it recovers the logo grouping) and is exact on the other two screens — not adopted, because on the one screen that can tell them apart it is still wrong. What it costs, exactly: of 3 disagreeing pairs of drawn elements across all three screens, 2 share opaque pixels — ptlogo_back2eff5 vs eff3 (22 568 px) and vs eff4 (32 395 px). The residual is one element's blend on one screen, and it is pinned by a test. The third pair (ptlogo2 vs ptlogo_tm) overlaps by bounding box but shares no opaque pixel; a box test called it a defect and the alpha says otherwise. Next: it is one element on one screen, so the cheap move is a fourth measured screen with a tied group — not more static guessing at fields that have all now been checked. 🔴 Attempted 2026-08-19 and blocked: advancing past the title is intermittent — 1 success in 3 attempts, same binary, same profile, same procedure. ✅ And now diagnosed one layer deeper: the title does act on Ⓐ — the press spawns a slot-(1F) loader thread (exactly once per run, at the keydown, never in a run that got no press). In the successful boot that thread immediately reads six paths from the on-disc cache and the menu appears; in a failed boot it starts and issues no file I/O ever. So "the title ignores Ⓐ" is withdrawn — the loader stalls. 🔴 Refuted as the cause: the cache-flush crash. All four of today's runs have zero GUEST-THROW, CRASH DUMP and Access Violation; the guest stays alive and polling. ✅ And now measured to the bottom: with kernel logging finally on (LOG_MASK=12 LOG_LEVEL=3 — the scripts' log_mask=13 had Kernel disabled, which is why no boot log ever held a kernel call), a captured failure shows the handler doing everything right — XamUserGetXUID, NtCreateEvent, ExCreateThread(entry=0x821748F0, CREATE_SUSPENDED), NtResumeThread — and the thread then never executing: zero kernel calls of its own, and 00:00:00 host CPU time while the process runs at 546 %. A spinning thread burns CPU; this one never ran. A lost resume is a race, which is the first explanation that fits the ~1-in-3 success rate. Next probe: Xenia's XThread create/resume pair — can a resume land before the host thread starts waiting? And capture one successful boot with kernel logging, to say whether the guest sequence differs at all. See canary-scripted-input-traps.md.

• ❔ Blend mode. Everything is straight alpha-over. The near-white flash quads (0xf0ffffff) and coloured ones (0x60ff0000) may be additive. The title capture cannot separate the two — its resting elements are all 0xffffff. A screen with a coloured primitive, captured, would.

• ❔ What marks a focused state in the file. The pairing rule that shipped is a naming convention, not a decoded field. kind = 0x3002 is a button record; whether a bit of kind marks the focused variant is the cheapest probe.

• ❔ What makes a bundle a screen rather than a fragment. is_composable admits 1 786 extra bundles, mostly 2–5-element button+glow fragments.

• ❔ What opt links. Refuted as focus; unexplained otherwise.

The investigation that got here follows, kept in full because most of it is refutations that were worth the cost.

The declaration table is not a paint order on every screen

Found 2026-08-17, building the Explorer's UI Screens browser on ui_layout. Status: 🔎 open — the pause menu is right, the title screen is not.

ui-rat-layout.md says the bundle's element declaration table lists elements "in back-to-front order", verified 11/11 on the tutorial pause bundle. That holds — the tutorial and in-mission PAUSE builds both composite correctly, and pgpeff02a → parent 3 / pgp_ttrl_btn10 at (546,288) / the 70 px button pitch all reproduce exactly.

GP_TITLE.pak build 7 does not. Painting in declaration order puts ptbase2.t32 (the full-screen background art, element 13) on top of the ptlogo1/ptlogo2 wordmarks (elements 0–5), which the real title screen obviously does not do. The pause bundles never caught this because their elements barely overlap.

What has been ruled out: there is no depth/layer key in the 60-byte declaration entry. Dumping every word across the title build's 30 entries, the unknown fields are constant — +28 is 0 everywhere, +44 is 0xffffffff everywhere, +56 is 0 everywhere — and +36, which the doc lists as 0xffffffff, is not a depth either: it is 0/1 only on the kind = 0x4 repeated-instance entries (ptlogo1/ptlogo2 copies), i.e. an instance index. So the order is not recoverable by sorting the table on any field it carries.

What that leaves. The background group is contiguous — elements 12, 13, 14 are pteff00.prm, ptbase2.t32, pteff04.t32, and 12 carries kind = 0x10, a flag no pause element has (theirs are 0x0 / 0x1 / 0x3002). pteff02.prm at 17 has it too. So 0x10 marking a PRMD primitive, and primitives opening a layer that draws beneath what precedes them, is the cheapest hypothesis — but it is a hypothesis, and "draw the .prm group first" would fit this one screen without being evidence of anything.

First step: composite GP_MISSION_SELECT / GP_READY_ROOM / GP_OPTIONS, which have both a background and overlapping foreground elements, and see whether their background sits at a 0x10-adjacent index too. Two more screens agreeing turns the hypothesis into a rule; one disagreeing kills it. The Explorer's screen render/screen info commands make that a minute's work per screen, and the per-element visibility toggles isolate a suspect element.

Meanwhile the viewer paints in declaration order and does not pretend otherwise — a screen whose background lands on top is showing you this bug, not a decode failure.

2026-08-18 — measured against the running game; three orderings refuted, and half the symptom was a different bug

The premise is confirmed by the oracle, which this entry had not had: a framebuffer capture of Canary on the title screen (captures/title-screen-oracle.png) shows the PROJECT SYLPHEED wordmarks (elements 0–5) drawn over ptbase2.t32 (element 13), which is a full-screen background. Declaration order is therefore not the paint order on this screen, and no reading of the element table changes that.

But part of what the render showed was not the paint order at all. In the capture ptbase2 covers the whole screen; the compositor drew it as a 960×540-visible slab starting at (320,180), because a keyframe's scale was being grown from the keyframe's corner instead of about the declared pivot. Fixed, and pinned against the capture by cross-correlation (peak at (0,0)) — see structures/ui-rat-layout.md. That was a real defect worth separating out: it moves 865 of the disc's 5 130 resting placements, on every screen, independently of any ordering question.

Three candidate orderings are now dead, all cheaply:

• The placement region is not a second ordering. Its keyframe groups carry an explicit element index, so they could be stored in a different order — they are not, on every build on the disc (placement_region_order_is_never_a_second_ordering,

  500 builds, identity every time).

• The RATC child order is not it either. For the title build it is the declaration order with the .prm elements absent — strictly less information, and it has no place to put ptbase2 other than where the table already puts it.
• Reverse declaration order is refuted by the same capture: it would draw ptbase2 (13) over ptcopyright (28), and the copyright line is visible.

The 0x10-adjacency first step was run, and it does not survive. The background is adjacent to a kind = 0x10 .prm element on both screens that have one — but on opposite sides. GP_TITLE build 7 is 12 pteff00.prm (0x10), 13 ptbase2.t32, 14 pteff04.t32; GP_MISSION_SELECT build 0 is 0 px_mission_base.tbm, 1 px_mission_eff00.prm (0x10). So "the .prm opens a layer that draws beneath what precedes it" cannot place both, and no rule keyed on the .prm's position orders the background. GP_READY_ROOM and GP_OPTIONS turned out not to be the third and fourth witnesses this entry hoped for: neither of their largest builds carries a .prm or a full-screen background at all, so they cannot discriminate.

What is still open, stated plainly: nothing in the bundle has been found that orders element 13 behind elements 0–5. Every ordering the file itself carries is now either identical to the declaration table or refuted by the capture. The next step is no longer static — it is either the guest code that walks this table, or a per-draw capture of the title screen showing the order the game submits.

Blocker, checked rather than assumed. The obvious move is to reuse Canary's existing RE instrumentation, which is already in the built binary on sylpheed-re. Neither hook can answer this:

• --log_draws (command_processor.cc) de-dups by a vertex-declaration fingerprint — shader hash + primitive type + per-stream element formats/offsets + index-buffer guest base — and writes each distinct one once. A screen's sprites share a declaration, so they collapse; and the record carries no texture identity and no per-frame submission order, only first-seen order. It is a mesh-format log, not a draw-order log.
• The F10 ship capture does preserve per-draw order within a frame and de-dups on (vertex base, WVP transform, index range), which would separate the elements — but it explicitly drops UI draws: if (pos_off_bytes < 0 …) return; // no float-position stream (UI/effects) — skip. It requires an f32x3 position attribute, which a 2D quad stream does not have.

So this needs a new hook in Canary — log each draw in submission order with its bound texture fetch (or its screen-space quad), gated behind a cvar the way the other two are — and therefore a build-canary run. That is the cost to state up front rather than discover halfway in; it is not a container limitation, just a long build plus a title-screen run.

2026-08-18 (later) — the hook was built and run; the order is now measured

log_ui_draws exists (Canary branch auto/re-ui-draw-order), and the title screen's paint order is ground truth rather than a candidate: ui-title-paint-order-capture.md.

Background first, then the back2 glow pair, then ptlogo1 + ptlogo_tm, then ptlogo2, then ptcopyright, then the PRESS Ⓐ BUTTON plate — i.e. declaration indices 13, 22|24, 23, 0, 11, 1, 28 and then two elements that are not in build 7 at all. Two more orderings die on that evidence (keyframe start time, resting-keyframe time), and one structural fact reframes the whole item: the screen composites two bundles (build 7 plus the one-element build 2 that is the button), so no single build's element table can be the paint order whatever its order.

Still open, and now sharper: the rule. The bundle's 60-byte declaration entry carries no depth field (dumped, above); the per-element .rat record has not been checked for one against this ground truth, and nothing yet explains how the two bundles are sequenced. Both are static questions again — the oracle side is answered.

2026-08-18 (third pass) — the bundle does not carry the order at all

Three more places checked, all empty, so the static avenue for this item is exhausted (detail and evidence in ui-title-paint-order-capture.md):

• the geometry has no depth. A UI quad's attribute 0 is k_32_32_32_FLOAT, so it carries a Z — and every Z in the capture is 0.00000. Submission order is the entire ordering.
• the declaration table has no key. Every word of every entry dumped for the build the game actually runs: +28 0, +32 0xffffffff, +36 0xffffffff (except an instance index on kind = 0x4), +44 0xffffffff, +56 0.
• the placement region has none either, including its per-group lead word, which is 0 for all 24 groups; and the region is followed straight by the RATC child stream, so there is no table hiding behind it.

Also corrected: the running screen is build 4, not the largest build 7 that screen info defaults to — the two disagree on sprite sizes and the capture matches build 4. The conclusions are unchanged, the indices are not.

So the next step is the guest code, not the file: the splash draw path from the emulator-era work (sub_821CC7A0, item vtable 0x820b30b4) submits with exactly the PS hash E59B2B3D this capture sees, and xenia-rs/sylpheed.db is available in the container.

And a second screen is NO LONGER BLOCKED, but it is not routine either. The main menu has been reached (screenshot in canary-scripted-input-traps.md), so the "Ⓐ is dead" reading is withdrawn. Not routine after all — see the 2026-08-19 tables in canary-scripted-input-traps.md: 4 of 5 successes without --log_ui_draws, 0 of 7 with it. An interleaved series refuted the boot-time confound (the latest title of all, 268 s, accepted Ⓐ; a 232 s title refused), and no mechanism exists for the flag — it is read only when F10 arms a capture, and F10 was never pressed. The variable was removed rather than believed — F10 now arms the capture unconditionally — and with it gone a fresh run still failed, so the flag is not the cause either. Net: Ⓐ succeeds about half the time and nothing measurable predicts which; five explanations are eliminated. The input path is now mapped statically (entry_point → sub_8216EA68 main loop → sub_822F1AA8 per-frame input → sub_82457038 pad poll → XamInputGetKeystrokeEx), and the poll itself is not state-gated, so the gate is in a consumer further up. Until that is separated, capturing a screen and navigating to it in the same run is not dependable. The earlier claim, kept: the title that ends the boot sequence accepts a single Ⓐ (2 of 2 at the time); the title the attract loop returns to accepts nothing (Ⓐ, START, B, BACK, X, Y — dozens of delivered presses). The proposed tell was refuted on the way: the two states draw 13 identical quads, ptbtn00 included, so they differ only to the guest. Recipe: first title after boot, one tap, and never tap during the boot (88 presses over the intro ends on a permanent black screen).

The second screen is captured — the main menu, GP_TITLE build 5 — and it does not discriminate: its background sits at declaration indices 1–2, so "declaration order" and "background first" predict the same sequence. Same failure mode as GP_READY_ROOM/GP_OPTIONS. The next screen worth capturing is one whose background sits late in its table, as the title's does.

The earlier reading, kept because it is what the evidence looked like: the title's Ⓐ leads into a content/save path that crashes the guest with --mem_watch=true and stalls it with --mem_watch=false. Three separate traps had to be cleared to establish that much — see canary-scripted-input-traps.md, which also carries the reproduction and the fix for two of them.

2026-08-18 (fourth pass) — the crash is named, and the code avenue is scoped

The crash PC resolves to an MSVC std::map/set erase that throws std::out_of_range from the game's cache-manager flush, and the trigger is now controlled: an incomplete on-disc cache throws ~100 s into a boot, a complete one never does. The access violation people have been chasing is only that throw returning, because this build does not unwind guest EH. And the handoff's suspect #1 is eliminated — cold cache with --mem_watch=false throws just the same, which withdraws a claim made here yesterday. See title-crash-stl-tree.md. That is a by-product of this item and belongs to whoever picks up the crash bisection.

For the ordering itself, three more negatives, all recorded in ui-title-paint-order-capture.md: the two time-based orderings were re-checked against build 4 (the previous pass used build 7's numbers, and build 7 is not what runs) and both still fail on the same element; and a fresh candidate — painter's order by resting Y — reproduces the capture to within a single transposition but is refuted by ptlogo_tm and by the background, so it is not the rule either.

The code avenue is scoped rather than walked: the splash item vtable 0x820b30b4 is real (25 slots, three construction sites), RTTI carries no class names disc-wide, and the format tags are fourcc immediates behind a virtual call rather than strings — so this needs a deliberate read of the UI engine, not a keyword search.

Capital ships assemble wrong in the viewer

Reported: 2026-07-30, by the user. Status: ✅ format-side cause found and fixed 2026-08-12 — see below for the 2026-08-10 diagnosis this supersedes.

The remaining format-side defect this entry pointed at (a shared turret decoding ~100× too large in some containers) was real and is gone. e303_wep_01 decoded as a 1600×2100×4800 block in Stage_S02, swallowing the e106 hull; requiring an index buffer to cover its vertex pool exactly moved it to the block every other container agrees on, and it now decodes 49×23×42 everywhere and places at ±179 on the hull. The same fix repaired e106_bdy_03 (a 600×1600×998 slab) and moved 29 anchors disc-wide, 22 of which had been carrying another resource's geometry under their own name. See structures/xbg7-mesh.md.

Two things are worth carrying forward rather than closing:

• the assembler was audited and exonerated — every composite node carries scale 1.0 and an orthonormal matrix, so nothing on that side inflates a part;
• no metric caught this. Coverage, cross-container consistency, the capture oracle and the twin invariant were all green while a 1 600-unit slab sat through the ship. It was found by rendering the ship and looking at it, and the numeric screens written afterwards to automate that check both failed.

The 2026-08-10 diagnosis follows, and its viewer-side pointers still stand.

Status (2026-08-10): 🔎 the format layer is exonerated. Runtime captures of three classes (f105, e105, e106) at controlled range reproduce assemble_ship to ≤0.43 units in translation and to 0.000 in rotation for every part that does not move; see ship-placement-capture-generalisation.md §4. So look at the viewer: first that it passes include_external = true (iso_loader.rs:4012 — with false an e106 loses its bridge and both nacelles, 5 parts instead of 11), then its own transform stack.

One real format-side bug was found on the way and is fixed: index-less parts (e105_brg) never matched their GN_Bridge_01 hardpoint, so 34 (stage, ship) entries — e102, e104, e105 across Stages 02–29 — assembled without a bridge. The other apparent exception (e105_eng_01 rotation) was an aggregation artefact and is 0.000.

The original report and its reasoning follow.

The reborn viewer builds capital ships from the split XBG7 parts via sylpheed-formats::ship::assemble_ship, and they come out wrong — parts in the wrong place / wrong orientation.

Why this is a real finding and not a known limitation: the RE write-up ship-placement-runtime-capture.md declares static assembly ✅ exact as of 2026-07-26 — 9-channel joint tables [TX TY TZ RY RX RZ SX SY SZ], Euler Ry·Rx·Rz, with ship::tests::static_assembly_matches_runtime_capture asserting static == runtime capture (T < 1.0, R < 0.02). So either the viewer is not using that path, or the claim generalises worse than the test suggests.

The likely gap: that test is one ship — the e106 destroyer, 8 parts plus two nacelles, two turrets and the hull mirror. Nothing pins the other classes. Rules that were derived from e106 and could easily be e106-specific:

• the engine cluster rig mounted at GN_Engine_01 (two mirrored nacelles + centre);
• "X-reflect the shared-geometry twin whose lateral offset opposes the geometry's dominant side" — a heuristic, not a decoded flag;
• cross-id turret instancing (×2).

First step (the oracle already exists): re-run the runtime capture on a different capital ship and diff static vs captured, exactly as e106 was done — F10 in the capture-ship-placement build of xenia-canary-native dumps the ship shader's c0..c2 WorldViewProjection rows per part; WV_ref⁻¹ · WV_p is the ship-space rigid transform, which is ground truth. Pick a class whose rig differs from e106 (different engine count, a ship with no sld, a carrier). Then extend static_assembly_matches_runtime_capture into a per-ship table so a regression in one class cannot hide behind e106 passing.

Also worth ruling out first, cheaply: that the viewer's own transform stack (scale, handedness, node-instance recursion) is not re-breaking a correct assembly — compare the viewer's placement against assemble_ship's output directly before blaming the format layer.

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Viewer: include_external is already on — that hypothesis is dead

Checked 2026-08-11. The item above names "first that it passes include_external = true (iso_loader.rs:4012)" as the cheap first step. It does: ShipBrowser::show_external defaults to true (iso_loader.rs:643), the checkbox reads it (ui.rs:1593) and it is threaded through RequestShipRender → build_ship_model → assemble_ship unchanged (ui.rs:1689, iso_loader.rs:4012). So a ship rendered by the viewer is the full external assembly, not the bare hull.

The viewer also does not have a transform stack of its own to blame: it bakes ScenePart::apply straight into the vertices and rotates normals by the same p.m (iso_loader.rs:4030-4062), so its placement is assemble_ship's output by construction. What remains unexcluded, in order of cheapness: the mirror handling (det < 0 reverses triangle winding only — a reflected part keeps its reflected geometry), Xbg7Model::models_named resolving the wrong sub-model when a resource name repeats, and the exhaust cones. Next step is a visual: the diagnosis has run out of things it can settle by reading, so the viewer needs to be run against a known-good class (e106) and its render compared with ship_render's.

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Viewer: the duplicate-resource-name hypothesis is dead too

Checked 2026-08-11. The diagnosis above left three candidates for why capital ships assemble wrong in the viewer: mirror handling, Xbg7Model::models_named resolving the wrong sub-model when a resource name repeats, and the exhaust cones. The second is now refuted, and comprehensively.

build_ship_model resolves each placement with base.iter().find(|m| m.name == p.resource) (iso_loader.rs:4041) — first match wins — so a repeated resource name inside a container would silently draw the wrong geometry. It cannot happen: decoding every XBG7 resource in all 22 stage containers gives 4 603 resources and zero repeated names.

Stage_S01  62/62      Stage_S07 323/323     Stage_S13 290/290     Stage_S25 351/351
Stage_S02 304/304     Stage_S08 388/388     Stage_S14  22/22      Stage_S26 318/318
Stage_S03 214/214     Stage_S09 316/316     Stage_S15 386/386     Stage_S27 321/321
Stage_S04 179/179     Stage_S10   7/7       Stage_S16  65/65      Stage_S28 118/118
Stage_S05  92/92      Stage_S11 157/157     Stage_S24 162/162     Stage_S29 386/386
Stage_S06 266/266     Stage_S12 376/376

Per-ship it is tighter still: e106 wants 9 distinct names and decodes exactly 9 models for 11 placements; e105 9 for 9; f105 5 for 6. Every placement resolves to the one model it names.

So two of the three candidates are gone (this one and include_external), leaving mirror handling and the exhaust cones — and the still-untried visual comparison, which remains the right next step.

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Viewer: mirror handling and the exhaust cones are cleared too — the static avenue is exhausted

Checked 2026-08-11. Both remaining candidates were tested across every ship on the disc, and neither shows the reported signature.

Mirror handling. The concern was that ScenePart::apply bakes R·(S·v)+T while the viewer takes its winding-flip decision from det(m) alone and rotates normals by m alone — both ignoring s. A mirror encoded as a negative scale would then reflect geometry without flipping winding, drawing the part inside-out. It never happens: across 1 485 assembled parts in all 22 containers there are 22 mirrored parts, every one with det(m) < 0, and zero parts with a negative scale or a non-uniform one. apply_twin_mirrors writes the reflection into m (negating its X column), so the viewer's flip always fires, and ignoring s for normals is harmless because s is always uniform.

Exhaust cones. These are the one piece of geometry the viewer invents — a cone at each GN_Jet/GN_SJet frame, because the real engine geometry is recessed and the game draws FX there instead. If they landed wrongly they would read exactly as "a part in the wrong place". Across 335 assembled ships, 192 of which have exhaust frames, not one cone sits outside its hull's bounding box (tolerance 10 % of the axis span).

Caveat, stated rather than glossed: "inside the hull box" does not prove a cone is right — orientation and size are untested, and a cone could be wrong while still inside. What it does rule out is the reported symptom for that part.

So every mechanism this diagnosis proposed is now eliminated: include_external, duplicate resource names, mirror handling, and cones-in-the-wrong-place. The format and assembly layers pass every static test available, and the visual comparison is no longer merely the next step — it is the only remaining one. Render e106 in the viewer beside ship_render's output of the same assemble_ship result; if they agree, the bug is in neither and the original report needs re-grounding against a specific ship and a specific expectation.

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⚠️ DIAGNOSED 2026-08-12 — a mis-decode; the locality fix was written, then withdrawn

Resolution at the end of this entry. Kept in full because the two wrong turns along the way (a "stray volume", then "monotonic anchoring") are the useful part.

⚠️ The format layer is NOT exonerated — but the cause is a MIS-DECODE, not a stray volume

Found 2026-08-11 by finally doing the visual, which the notes above kept naming as the next step. It overturns their conclusion.

Render e106 from the static assembly and from the baked runtime capture and compare — ship_render does both:

	placements	parts
runtime capture (ground truth)	8	bdy_01…04, brg_01, eng_01, eng_02, wep_02_01
assemble_ship(--static)	11	the same 8, plus e303_wep_01 ×2 and a second e106_eng_01

The render makes it obvious: the destroyer sits inside a white slab that dwarfs it (capture). That slab is e303_wep_01, and its own geometry is:

e303_wep_01     172 verts, 110 tris   bounds X[-1000, 600] Y[-1050, 1050] Z[-2400, 2400]   1600 x 2100 x 4800
e106_wep_02_01 1002 verts, 772 tris   269 x 179 x 417      ← what a real e106 turret looks like
e106_brg_01     202 verts, 202 tris   105 x  76 x 305

110 triangles, perfectly round axis-aligned bounds, and bigger than the ship it is mounted on.

CORRECTION (same day, one iteration later): it is not a volume — it is a bad decode

The first reading of this was that e303_wep_01 is a collision/trigger volume the assembler wrongly draws. That is wrong, and the evidence that settles it is decoding the same resource from every container that holds it:

Stage_S01   172 verts 110 tris   X[-24.5, 24.5] Y[0.0, 23.4] Z[-20.8, 20.8]   ← 49 × 23 × 42, a turret
Stage_S02   172 verts 110 tris   X[-1000, 600] Y[±1050]      Z[±2400]         ← 1600 × 2100 × 4800
Stage_S03…  172 verts 110 tris   49 × 23 × 42  (correct)
Stage_S08   …                    1600 × 2100 × 4800
Stage_S26   …                    1600 × 2100 × 4800

Same resource, same vertex and triangle count, decoding correctly in eleven containers and wrongly in exactly three (Stage_S02, S08, S26). So:

• the placement is legitimate — e303_wep_01 is a small shared turret, cross-mounted on e101 and e106, and at its true size it is unremarkable;
• the original author's explanation of the capture's silence (vbase dedup) stands, and my "dedup would show one, not zero" objection does not survive: with the correct decode the turret is small, ordinary geometry;
• the defect is in the mesh decoder, which resolved this resource's vertex data differently in three containers.

The render and the symptom are real; the cause named in the first version of this entry was not.

The part that matters more than this one resource

The decoder can produce wrong geometry without declining. The XBG7 audit counted 814 resources it refuses — a visible, honest failure. This is the other kind: e303_wep_01 decodes "fine" in Stage_S02 and is silently 100× too large. Screening for the signature (bounds that are exact multiples of 50 with a span over 1000) flags 22–32 models in each of S02, S03, S08, S26, S27 — but that screen also catches legitimate e_rou_* composite proxies, so it is a candidate list, not a count of bugs.

Next: diff the anchor scan's chosen vb0 for e303_wep_01 between Stage_S01 (correct) and Stage_S02 (wrong) — same resource, two outcomes, so the divergence is directly observable — then use whatever distinguishes them to add a post-decode sanity check, so a silent 100× mis-decode becomes a decline.

Why this was missed

assemble_ship treats every rou_* node in the composite as a drawable part, and the doc comment states the cross-id mount as intended behaviour — "INCLUDING repeated instances and cross-id turret mounts (rou_e303_wep_01_root ×2 on the e106 hull)" — with ship::tests::static_assembly_matches_runtime_capture asserting count("e303_wep_01") == 2. The absence from the capture was explained away as vbase dedup, but dedup would show one instance, not zero.

The test cannot catch it either: it walks the capture's parts and looks each up in the static output, so extra static placements are invisible to it. That is the same shape of gap as the earlier include_external hypothesis — a test that can only fail one way.

Scope, stated carefully

Sweeping all 335 assembled ships for the signature ship-scale span with under 400 triangles flags 20 ships and 58 placements over 28 distinct resources (e005_ant_*, f001_ant_*, f002_bdy_*, f301_barrel, f303_body, e303_wep_01, …). Only the e106/e303_wep_01 case is proven — by render, by capture absence, and by geometry. Some of the others may be legitimately large low-poly parts, and each needs the same three checks before being called a bug.

Still true, and independent of the correction above: static_assembly_matches_runtime_capture walks the capture's parts and looks each up in the static output, so extra static placements can never fail it. That is worth fixing regardless — it is the same one-way-test shape as the earlier include_external hypothesis.

Also unchanged: only two cross-id placements exist fleet-wide (e303_wep_01 on e101 ×24 and e106 ×36, across 335 assembled ships), so cross-id mounting is a narrow, real feature rather than a systemic guess.

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Resolution (2026-08-12)

anchor_pool_mesh took the first candidate in file order from a container-global scan, so a resource could be handed another resource's block whenever both shared (stride, vertex count, index count). Fixed by anchoring each resource near its descriptor neighbours (two-pass: learn, then re-anchor).

• it took inconsistency 125 → 51 with coverage unchanged, and made e106 render correctly (after)
• but it flipped the e106 twin-mirror decision, which static_assembly_matches_runtime_capture (ISO-gated, so it skips in a plain cargo test) catches against the runtime capture — so it was reverted
• the user-reported "capital ships assemble wrong" is therefore diagnosed, not yet fixed; see xbg7 for what the real fix needs

Still open from this entry: static_assembly_matches_runtime_capture walks only the capture's parts, so extra static placements still cannot fail it.

2026-08-18 — that last line was stale, and the residual gap is now closed too

The one-way-test complaint had already been fixed when this entry was written down: 64d372c (the revert commit itself) added an extras check, so "extra static placements cannot fail it" has not been true since. Checked rather than assumed — perturbing the expectation makes the test fail with the real disc behind it, so it runs and is live, not a SYLPHEED_ISO-less skip.

But it compared a set of resource names, which leaves one direction open: a resource placed twice when the capture lists it once changes no set. That is not hypothetical — a duplicated instance is exactly what a bad node walk emits, and the two legitimate duplicates here (e106_eng_01, e303_wep_01) are the reason the test had to special-case counts at all. Replaced with the full multiset, pinned to the e106 ground truth:

e106_bdy_01 1  e106_bdy_02 1  e106_bdy_03 1  e106_bdy_04 1  e106_brg_01 1
e106_eng_01 2  e106_eng_02 1  e106_wep_02_01 1  e303_wep_01 2

— 9 resources, 11 placements, against the capture's 8 dedup'd parts. That subsumes the two hand-written count assertions, and it now fails on an extra resource, a missing one, and a duplicated one. Refuted before believing: declaring e106_bdy_01 twice makes it fail, with the real multiset on the left.

Not closed by this, and worth keeping separate: the multiset is e106's alone. The generalisation this entry originally asked for — a per-ship table so a regression in one class cannot hide behind e106 passing — still needs a runtime capture of a second capital ship.

That entry's stated blocker is stale (checked 2026-08-19): the ship capture is in the current build — RequestShipCaptureFrame / CaptureShipDrawForRE are in command_processor.cc on auto/re-ui-draw-order, and F10 wrote a 2.9 MB xenia_ship_capture_01.log from this session's binary. No separate capture-ship-placement build is needed.

What blocks it now is the cache-flush crash, not navigation — measured 2026-08-19. tools/re-capture/tutorial_launch.sh (which retries whole boots, because re-pressing the same title never works) gets all the way from the title through the main menu to DIFFICULTY and then SELECT DATA, and the guest dies there at 0x82307128 — the same std::map/set erase as the boot-time throw, 537 stacked dumps, with --mem_watch=false. See title-crash-stl-tree.md.

So a second capital-ship capture needs that crash dealt with first. Everything up to the save-slot screen is now scripted and works, and one run got past it — SELECT DATA reached with zero crashes, slot chosen, the game proceeding into a cinematic — before crashing at the same 0x82307128. The crash is intermittent in where it fires, not whether, so there is no menu route around it. See title-crash-stl-tree.md for the end-to-end measurement and for what has been ruled out (--mem_watch=false, twice).