Merge pull request #44 from jkdansereau/docs/d217-m89-pitch-hypothesis-refuted

docs(D217): M-89 — refute the gfx_dp_load_tlut pitch/width=1 hypothesis

docs/dev/findings.md

@@ -439,7 +439,7 @@ covers D24–D69; the log continues in §H (D32 procedure, D70–D121).
 | D214 | **Keyboard rebinding — `[Input.Bind]` config section (M-83, port-only, PD parity, Phase 4 debt).** `port/src/input.c` gains 12 gameplay actions (Forward/Back/StrafeLeft/StrafeRight/TurnLeft/TurnRight/Fire/Aim/Action/Cancel/LeanLeft/Start), each a comma-separated list of up to 4 SDL scancode names (`Input.Bind.Forward = W,Up` …). `inputRebuildBinds()` (called from `inputInit()`, after `configLoad()`) parses them via `SDL_GetScancodeFromName`; unknown names log a warning and are skipped. The old hardcoded `keyDown(ks, SDL_SCANCODE_*)` block in `inputComputePad` is replaced by `actHeld(ks, IA_*)`. Mouse buttons (fire = LMB, aim = RMB) stay hardwired; the mouse-wheel weapon-cycle A-pulse is untouched. **Defaults reproduce the previous FPS layout exactly — verified: all 20 default key names round-trip to the identical `SDL_Scancode` the old code used (`SDL_GetScancodeFromName` test, 0 mismatches).** Config-file only (no in-overlay text entry — matches PD, whose rebinding is also file-driven); a fresh `ge007.ini` gets the full `[Input.Bind]` block with the defaults visible. | **PARTIAL — M-84: code PASS (alt/ctrl); one doc-only fix.** LANDED, port-only, no `#ifdef PORT`; build clean. One doc bug fixed (no code change): `config.c` groups keys by the substring *before the last `.`*, so the section header is **`[Input.Bind]`**, not `[Bind]` — earlier finding/commit/QOL text was wrong. Working syntax: put `Fire = Left Alt` under `[Input.Bind]`, or write a fully-qualified `Input.Bind.Fire = Left Alt` line anywhere (`config.c:307`). Separately: the pause→**watch menu** does not wire Esc→back (still Enter to open/close/back) — pre-existing, `options.c`, minor. |
 | D215 | **1P weapon viewmodel never drew in-level — `gunRenderFirstPersonGunModels` builds its `ModelRenderData` from a reinterpret across separately-declared adjacent globals that only works on N64 (M-83, D3x/ABI class; retires VIEWMODEL-RESEARCH.md).** The N64 line `renderdata = *(ModelRenderData *)&D_80035CC0;` (`gunfire.c`) casts the lone `u32 D_80035CC0 = 0;` to a whole `ModelRenderData` and reads on into the next declared global, `u32 D_80035CC4[] = {1, 3, 0, 0, …}` (`gun.c`) — yielding `{ basemtx=0, zbufferenabled=1, flags=3, rest=0 }` **only because the N64 linker lays the two globals out contiguously in declaration order and pointers are 4 B**. On x86-64 it breaks twice: `ModelRenderData`'s three pointer members (`basemtx`/`gdl`/`mtxlist`) widen 4→8 B so `flags` is no longer at struct offset 8, and C guarantees nothing about the two globals' relative placement. Measured (`GE_DVM=1`, BUNKER1): `renderdata.flags == 0`, so **every** weapon-model DL node was gated off at `modelRenderNodeGundl` (`(renderdata->flags & 1)`), and `subdraw()` for the weapon emitted just its `gSPSegment` — 1 gfx command instead of ~150. All three VIEWMODEL-RESEARCH.md ranked suspects were ruled out by the same probe first: `field_87F==1` (gate open), `RootNode` valid, `numRecords 22 < 192` (pool fine), node walk visits 24+ valid `DL`/`SWITCH`/`BSP` nodes. **Fix:** `#ifdef PORT` → set the three fields explicitly (`zbufferenabled=TRUE; flags=3;`), N64 line verbatim under `#else`. ABI/layout only, no logic change. | **FIXED (`src/game/gunfire.c`, `#ifdef PORT`).** Build clean. `GE_DVM=1` post-fix: `flags=0x3`, weapon `subdraw()` now emits **153** gfx commands (was 1). Regression sweep crash-free. `GE_DVM` gate+render probes left in, env-gated (cf. `GE_D193*`). **Owed:** one BUNKER1 eyeball that the gun model is actually visible + correctly posed (headless can't see pixels; the DL is now provably generated). The committed `bunker1` golden will need re-baselining — the gun now renders in-frame. |
 | D216 | **`Game.SkipIntro` — boot straight to the file-select menu (M-83, port + one `#ifdef PORT` game-code line, PD parity, Phase 4 quick win).** New `s32 portSkipIntro` (`port/src/video.c`, `configRegisterInt("Game.SkipIntro", 0, 1)`), read once in `src/game/lv.c` at `LEVELID_TITLE` stage load — in the `else` of the existing `GE_STARTMENU` `#ifdef PORT` block. When set it does what every intro stage's own `!is_first_time_on_main_menu` branch does (`front.c`): `is_first_time_on_main_menu = FALSE; prev_keypresses = TRUE; maybe_is_in_menu = TRUE; menu_update = MENU_FILE_SELECT;` — i.e. it reuses the game's own post-intro route rather than inventing one, so the legal screen + Nintendo/Rare/GoldenEye logo attract loop is skipped. `GE_STARTMENU` still wins when both are set. Default 0 ⇒ untouched. | **LANDED + VERIFIED this session.** Build clean. Headless: default boot frame 90 = the TWYCROSS classification screen (10% non-black), `SkipIntro=1` frame 90 = the **SELECT FILE menu** (folders/photos/cursor all render, 89% non-black), no crash across repeated boots. Screenshots captured + eyeballed. **Owed:** nothing critical — a human boot to confirm the menu is fully interactive (cursor moves, a save slot opens). |
-| D217 | **1P weapon viewmodel + third-person Bond model textures render garbled — wrong/stale palette on model-DL CI textures (M-84, user QA; surfaced by D215 now that the viewmodel draws).** BUNKER1/Facility: the PP7 viewmodel has yellow+blue scrambled texels and a solid **green** patch by the hammer; Bond's in-game **watch face** shows the same green mismatch; user reports the **third-person Bond world model** does this "sometimes" too. Signature matches the **D161 family** — a CI-format tile drawn without the expected TLUT state, so fast3d's `import_texture` indexes a **stale `rdp.palette`**. D161 fixed the explicit `G_TT_NONE` case; this looks like model DLs not emitting `gDPLoadTLUT` through the port path, or the palette segment not resolving for weapon/character geometry. **Not a D215 regression** — D215 only un-gated the DL. | **OPEN — root cause characterised (M-86); needs an upstream/asset-pipeline fix.** Headless repro: `-level_34` FACILITY ~frame 300–400, PP7 **grip = flat green block** + green ring at the barrel joint + green-cast hand; barrel/slide upper correct black. Also green on `-level_30` DEPOT. **Clean on `-level_09` BUNKER1** (A/B control — same PP7, identical DL). **Two separate defects found:** ① **Wrong palette bound (the visible green — upstream of fast3d).** The grip is a CI4 solid-fill of palette index 0. Green `(24,65,0)` == RGBA5551 `0x1A00` == `rdp.palette[0]` at grip-import time. The grip's `count=1` model `G_LOADTLUT` is fed **different source bytes per level** for the same tile: BUNKER `00 01`→`PD_BE16`→`0x0001` (black ✓), FACILITY `1a 00`→`0x1A00` (green ✗). fast3d byteswaps + stores faithfully (proven correct by BUNKER) — the wrong bytes *arrive* from the model-DL / segment-address path. Strong tell: every *larger* model TLUT has `raw[0]==raw[1]==0x0000` with real colour from index 2 ⇒ GE's model-TLUT payload likely carries a **4-byte (2-entry) leading zero pad**, OR the port's model-TLUT source pointer is **4 bytes / 2 entries too low** (then the `count=1` grip load reads the tail of the preceding CI blob — BUNKER lucky, FACILITY not; fits "widespread across levels + weapons"). Ruled out this session: not tail-overflow (index 0 is in-range; matches M-85 `GE_D217Z`), not the fast3d byteswap. **Next:** dump the grip TLUT `G_SETTIMG` target vs the ROM/`pcmodels` sidecar PP7-grip material bytes; confirm the 4-byte offset vs N64; fix in model-DL segment resolution or `tools_pc/d43_emit.py` blob placement (sidecar regen). ② **CI texture-cache collision (proven, real, separate; fix landed).** `gfx_texture_cache_lookup` (`gfx_pc.cpp:522`) keyed CI textures on `{addr, palette_addrs[0/1], palidx, size_bytes}` with **no palette-content check**; GE reissues `gDPLoadTLUT` from repeated scratch-arena addresses with different content, so a later material could take a stale HIT and sample another material's decoded palette. **Fix on branch `fix/d217-model-texture-palette` (commit `f6fc0399`):** FNV-1a hash of the 512-byte `rdp.palette` computed only in `gfx_dp_load_tlut()`, added to the CI cache key (`port/fast3d/gfx_pc.{cpp,h}`, fast3d-internal, no `#ifdef`). Cheap, cannot worsen a decode; **owes a full 21-level `verify.sh sweep`** before merge (touches every palettized world texture's import path — cache-churn risk only). Does **not** fix defect ①. Screenshots: session scratchpad `d217/`, `fac_gun_crop.png`. Cross-ref `docs/dev/GRAPHICS-BACKLOG.md`. **User playtest matrix (M-87, raw notes — not yet triaged):** DAM/PPK: watch still green; AK47 viewmodel has white (missing-texture) patches on the magazine + barrel. FACILITY: PPK garbled **green AND blue**; 3rd-person Bond world model shows greenness on level load-in; AK47 has "weird blue / glitched" textures. JUNGLE: M16 viewmodel is orange in spots. Confirms multi-weapon (PP7/AK47/M16), multi-color (green/blue/white/orange) — consistent with the upstream model-TLUT-source theory (different trailing garbage per weapon/material) rather than one single fixed offset. **Scope clarified (M-87):** not just Bond's 1P viewmodel / 3P world model — **NPC-held weapon models (other characters' guns in third person) show the same glitched-color/white-missing texture symptom.** So the defect is in the shared weapon-model-DL/TLUT path used by *any* character holding that weapon, not something specific to Bond's model or the 1P viewmodel rig — widens the likely fix surface (weapon model loading in general) beyond "Bond's gun." **M-87 clarification:** not uniform across levels — severity and glitch *type* both vary per level (some levels show it lightly, some not at all in a given session, and the specific wrong-color/missing pattern differs), consistent with the per-material trailing-garbage theory rather than one fixed global offset. **M-88 update: defect ① is NOT a `tools_pc/d43_*.py` sidecar bug — the theory in this row is refuted; the model converter never touches texture/palette bytes at all.** Line truncated
+| D217 | **1P weapon viewmodel + third-person Bond model textures render garbled — wrong/stale palette on model-DL CI textures (M-84, user QA; surfaced by D215 now that the viewmodel draws).** BUNKER1/Facility: the PP7 viewmodel has yellow+blue scrambled texels and a solid **green** patch by the hammer; Bond's in-game **watch face** shows the same green mismatch; user reports the **third-person Bond world model** does this "sometimes" too. Signature matches the **D161 family** — a CI-format tile drawn without the expected TLUT state, so fast3d's `import_texture` indexes a **stale `rdp.palette`**. D161 fixed the explicit `G_TT_NONE` case; this looks like model DLs not emitting `gDPLoadTLUT` through the port path, or the palette segment not resolving for weapon/character geometry. **Not a D215 regression** — D215 only un-gated the DL. | **OPEN — root cause characterised (M-86); needs an upstream/asset-pipeline fix.** Headless repro: `-level_34` FACILITY ~frame 300–400, PP7 **grip = flat green block** + green ring at the barrel joint + green-cast hand; barrel/slide upper correct black. Also green on `-level_30` DEPOT. **Clean on `-level_09` BUNKER1** (A/B control — same PP7, identical DL). **Two separate defects found:** ① **Wrong palette bound (the visible green — upstream of fast3d).** The grip is a CI4 solid-fill of palette index 0. Green `(24,65,0)` == RGBA5551 `0x1A00` == `rdp.palette[0]` at grip-import time. The grip's `count=1` model `G_LOADTLUT` is fed **different source bytes per level** for the same tile: BUNKER `00 01`→`PD_BE16`→`0x0001` (black ✓), FACILITY `1a 00`→`0x1A00` (green ✗). fast3d byteswaps + stores faithfully (proven correct by BUNKER) — the wrong bytes *arrive* from the model-DL / segment-address path. Strong tell: every *larger* model TLUT has `raw[0]==raw[1]==0x0000` with real colour from index 2 ⇒ GE's model-TLUT payload likely carries a **4-byte (2-entry) leading zero pad**, OR the port's model-TLUT source pointer is **4 bytes / 2 entries too low** (then the `count=1` grip load reads the tail of the preceding CI blob — BUNKER lucky, FACILITY not; fits "widespread across levels + weapons"). Ruled out this session: not tail-overflow (index 0 is in-range; matches M-85 `GE_D217Z`), not the fast3d byteswap. **Next:** dump the grip TLUT `G_SETTIMG` target vs the ROM/`pcmodels` sidecar PP7-grip material bytes; confirm the 4-byte offset vs N64; fix in model-DL segment resolution or `tools_pc/d43_emit.py` blob placement (sidecar regen). ② **CI texture-cache collision (proven, real, separate; fix landed).** `gfx_texture_cache_lookup` (`gfx_pc.cpp:522`) keyed CI textures on `{addr, palette_addrs[0/1], palidx, size_bytes}` with **no palette-content check**; GE reissues `gDPLoadTLUT` from repeated scratch-arena addresses with different content, so a later material could take a stale HIT and sample another material's decoded palette. **Fix on branch `fix/d217-model-texture-palette` (commit `f6fc0399`):** FNV-1a hash of the 512-byte `rdp.palette` computed only in `gfx_dp_load_tlut()`, added to the CI cache key (`port/fast3d/gfx_pc.{cpp,h}`, fast3d-internal, no `#ifdef`). Cheap, cannot worsen a decode; **owes a full 21-level `verify.sh sweep`** before merge (touches every palettized world texture's import path — cache-churn risk only). Does **not** fix defect ①. Screenshots: session scratchpad `d217/`, `fac_gun_crop.png`. Cross-ref `docs/dev/GRAPHICS-BACKLOG.md`. **User playtest matrix (M-87, raw notes — not yet triaged):** DAM/PPK: watch still green; AK47 viewmodel has white (missing-texture) patches on the magazine + barrel. FACILITY: PPK garbled **green AND blue**; 3rd-person Bond world model shows greenness on level load-in; AK47 has "weird blue / glitched" textures. JUNGLE: M16 viewmodel is orange in spots. Confirms multi-weapon (PP7/AK47/M16), multi-color (green/blue/white/orange) — consistent with the upstream model-TLUT-source theory (different trailing garbage per weapon/material) rather than one single fixed offset. **Scope clarified (M-87):** not just Bond's 1P viewmodel / 3P world model — **NPC-held weapon models (other characters' guns in third person) show the same glitched-color/white-missing texture symptom.** So the defect is in the shared weapon-model-DL/TLUT path used by *any* character holding that weapon, not something specific to Bond's model or the 1P viewmodel rig — widens the likely fix surface (weapon model loading in general) beyond "Bond's gun." **M-87 clarification:** not uniform across levels — severity and glitch *type* both vary per level (some levels show it lightly, some not at all in a given session, and the specific wrong-color/missing pattern differs), consistent with the per-material trailing-garbage theory rather than one fixed global offset. **M-88 update: defect ① is NOT a `tools_pc/d43_*.py` sidecar bug — the theory in this row is refuted; the model converter never touches texture/palette bytes at all.** Line truncated
 | D218 | **Wide FOV exposes the per-level draw-distance / fog boundary — "blue artifacting" down long peripheral sightlines (M-84, user QA on the D211 FOV slider).** BUNKER→**Dam main tunnel** at `FovScale` ~150: geometry / backdrop past the level's fog-end distance shows at the widened frustum edges (blue = Dam's fog tint). Not a render bug — `fogLoadCurrentEnvironment` (`bgfog.c:305`) does `viSetZRange(Visibility.BlendMultiplier, Visibility.FarFog)`, so **`Visibility.FarFog` is both the far clip plane and the fog-saturation distance**; levels tune it for the stock ~60° FOV. | **Logged (M-84), fix proposed + parked.** Plan: `Video.DrawDistance` (percent, 100–400, default 100 ⇒ no-op) `#ifdef PORT` multiplier on `FarFog` at `bgfog.c:305` (+ the direct `arg0->Visibility.FarFog` reads just below, so fog stays consistent) plus `Video.DrawDistanceAutoFov` (0/1, default 1 — couples draw distance to `FovScale` unless `DrawDistance` is set explicitly). Clamp effective multiplier ≲2.5× (small znear ⇒ far-field z-fighting risk). **M-87: user confirms still occurring** at high FOV, and — reversing the earlier "not implemented by user request" — **now wants `Video.DrawDistance` implemented as a real QoL feature**, plus scope it to cover **LOD/detail-distance in general**, not just the fog/far-clip boundary this row root-caused. Open question for that broader ask: does GE have a *separate* geometry/object LOD-swap or draw-culling distance mechanism (distinct from `Visibility.FarFog`) worth exposing too, or is fog-distance the only meaningful "how far can you see" knob in this engine? Check for a per-object visibility-radius / simple-model-swap system before assuming `FarFog` is the whole story. |
 | D219 | **PPK explosions render purple on Dam (M-87, user QA, "not 3D but noting").** Effect-color defect, not a texture-decode one — likely the D172 particle-color family (`gfx_lod_tile_offset` / `G_CC_INTERFERENCE` channel-order class) recurring on a different particle type/weapon than the D172 fix covered, or a fresh instance of the same class. | **OPEN — observed, not investigated.** Next: `GE_PCDUMP`/`GE_TEXDUMP` a Dam PPK explosion; check whether it's the same `gfx_lod_tile_offset` tile-sampling defect D172 fixed for blood, on an explosion DL D172's fix didn't touch. |
 | D220 | **1P muzzle flash position shifts upward at higher `Video.FovScale` (M-87, user QA, Jungle/M16).** Likely shares D211's noted residual: the viewmodel draws through `c_perspfovy`/unscaled fovy while the world view is FovScale-scaled (`fr.c:737`), so a flash sprite anchored to viewmodel-space vs. screen-space math can drift as the two diverge more at higher scale. | **OPEN — observed, not investigated.** Next: find the muzzle-flash placement code (gun DL attach point vs. screen-space billboard), check what FOV/projection it uses vs. `frFovY`/`portFovScale`, reproduce headless with `FovScale` 100 vs 150 on Jungle M16. |
@@ -8566,3 +8566,86 @@ special case as the mechanism.
 - No `tools_pc/d43_*.py` file was modified; `git status` in this worktree
   shows only the two docs edits (this section + the D217 table-row pointer)
   plus a local `data` symlink (not tracked/committed) used for the build.
+
+## D217 — M-89: the `gfx_dp_load_tlut` width=1/pitch hypothesis is REFUTED (it computes correctly by design); new lead pointed at the runtime texpool arena + image-table conversion, not the model sidecar
+
+A local-Qwen triage dispatch (read-only, no edits) proposed hardcoding
+`pitch = 1` in `gfx_dp_load_tlut` (`port/fast3d/gfx_pc.cpp:2214`,
+currently `pitch = rdp.texture_to_load.width + 1`), on the theory that N64
+LOADTLUT addressing never strides by the SetTextureImage width and the
+port's `+1` computation was wrong. **Verified by hand and refuted before
+applying it — do not repeat this fix:**
+
+- `gDPSetTextureImage`/`gSetImage` (`include/PR/gbi.h:3097-3111`) pack the
+  RDP command word as `_SHIFTL((width)-1, 0, 12)` — i.e. the **raw** command
+  field the port reads back (`C0(0,10)` at the `G_SETTIMG` handler,
+  `gfx_pc.cpp:2786`) is `width - 1`, not `width`. `texWriteLoadToTmemAddr`
+  (`tex.c:503,519,629,643`) always calls `gDPSetTextureImage(..., width=1,
+  ...)`, so the raw field is `1-1=0`, and `pitch = 0 + 1 = 1` **already**,
+  for every model-DL TLUT load in the game. The proposed patch is a no-op
+  for this call site — it changes nothing about the reported bug, because
+  the code it "fixes" already computes the value it wants.
+- Continuing the derivation with `pitch=1` confirmed: `gfx_dp_load_tlut`'s
+  `base = addr + pitch*ult + uls` reduces, for every call from
+  `texWriteLoadToTmemAddr`'s `gDPLoadTLUT07(uls, ult, tex->unk0a + uls,
+  ult)`, to **`base = addr + len`** regardless of the internal `uls`/`ult`
+  split (`tex.c:530-541`; the split exists only to keep both RDP command
+  fields inside their 10-bit range when `len` is large — it cancels out in
+  the `pitch=1` address math). `addr` is `tex->data` (the `SetTextureImage`
+  dram pointer) and `len` is `texGetDepthAndSize`'s halfword-converted
+  pixel-data length. This is exactly the documented on-disk/in-arena layout
+  from `texInflateZlib` (`image.c:320-326`: palette bytes appended
+  immediately after `totalbytesout` bytes of pixel data) — **the addressing
+  scheme is self-consistent and correct by inspection**, assuming `len`
+  (computed from `tex->width`/`height`/`depth`/`maxlod` via
+  `texGetLineSizeInBytes`) truly equals the pixel-byte count the decoder
+  actually wrote (`totalbytesout` before the palette-append loop). Also
+  confirmed `tex->unk0a = numcolours - 1` (`image.c:238`) exactly explains
+  the `count = width*height = unk0a+1` term in `gfx_dp_load_tlut` — matches
+  the M-85 `GE_D217Z` "count=1/28/125/172/193" observations precisely (a
+  **genuine 1-color palette** for the grip tile, not a partial/truncated
+  load of a larger one).
+- **New question this raises, not yet answered:** if the addressing math is
+  correct and `numcolours=1` is a real, intentional 1-entry palette for
+  this tile, then the SAME `texturenum` decoded from the SAME ROM bytes
+  should produce the SAME single color on every level — it does not
+  (`0001` on BUNKER1 vs `1a00` on FACILITY). That points away from a
+  decode-math bug entirely and back toward either (a) **the bytes handed to
+  the decoder differ per level** (i.e. an image-table/asset-resolution
+  issue — but a *different* one than the already-ruled-out model-DL
+  `TextureID`/`d43_emit.py` path; `texLoad` sources compressed bytes from
+  `g_Textures[texnum]` offsets into `_imagesSegmentRomStart`, a wholly
+  separate table/segment from the per-model `Globalimagetable` that
+  `port/src/gimgfixup.c`/D68 already fixes — **not yet audited for this
+  bug**), or (b) **the shared texpool arena serves a stale/aliased
+  `tex->data` pointer** for what should be a fresh per-level decode (the
+  arena is a two-ended allocator, `struct texpool` `leftpos`/`rightpos`,
+  reused across many textures per level per `texLoad`/`image.c:2414-2519`;
+  if `bytesout` returned by `texInflateZlib`/`NonZlib` for the LOD-limited
+  or shrink-paletted paths (`image.c:277-318`, the `forcenumimages >= 2`
+  branch with its `if (totalbytesout + imagebytesout > 0x800) { maxlod = j;
+  break; }` early-exit) doesn't exactly match what `texGetDepthAndSize`
+  later assumes was written for a *different* texture that landed nearby,
+  a later texture's palette read could land on an adjacent texture's
+  bytes — this would explain "same weapon, different levels, different
+  wrong colors" as a level-dependent *decode order/adjacency* effect, not
+  a fixed byte offset).
+- **Explicitly ruled out this session (in addition to the M-88 sidecar
+  ruling):** `gfx_dp_load_tlut`'s pitch/address computation itself
+  (`gfx_pc.cpp:2202-2237`) — confirmed correct by hand-derivation against
+  the GBI packing macros, not just "not yet disproven."
+- **Confidence:** HIGH that the proposed `pitch=1` patch is a no-op and
+  must not be applied/merged. MEDIUM on the two new leads above — neither
+  was instrumented or built this session (time-boxed to the math
+  derivation); the game-fed vs. arena-staleness question is the right next
+  probe (an env-gated log of `g_Textures[texnum]` offset + decoded byte
+  count + `pool->leftpos`/`rightpos` delta, on the exact FACILITY repro
+  frame, would disambiguate directly).
+- **For whoever picks this up next:** do NOT re-propose changing
+  `gfx_dp_load_tlut`'s pitch formula without first checking whether the
+  bytes arriving at `texInflateZlib`'s `src` parameter (i.e. what
+  `g_Textures[g_TexNumToLoad]`/`_imagesSegmentRomStart` resolves to) are
+  actually identical across BUNKER1 and FACILITY for this `texturenum` —
+  that is the one load-bearing assumption ("same weapon, same ROM bytes")
+  this whole investigation has taken for granted but never directly
+  checked with a probe.