docs: D202 M-63/M-65/M-66/M-66b + D204 writeups; audio status in README/AGENTS

- findings.md: D202 full session history (M-63 live repro, M-65 voice-leak
  guard + sndCreatePostEvent unstub, M-66 root cause — sound 203 infinite
  ADPCM loop played fire-and-forget = faithful N64 quirk; M-66b option-C
  expiration implemented + measured) and D204 (AI-queue starvation, fixed
  + measured). Index row updated; findings-index.csv regenerated.
- GE-ENV-PROBES.md: D202 probe set documented ([EXPIRE] marked permanent).
- GRAPHICS-BACKLOG.md: D172 / D176 / 1P-viewmodel rows point at the new
  research docs.
- README + AGENTS.md: audio status corrected (mixer landed post-v0.1.0;
  Phase 3 in progress, not 'no audio').

docs/dev/GRAPHICS-BACKLOG.md

@@ -18,16 +18,16 @@ once the game is playable start-to-finish without crashes.
 | **D149** | Front-end MISSION COMPLETE / mode-select 3D models (dossier, wallets) render as garbled full-screen geometry or not at all — one of the compiled sub-DLs (seg5+0x9ee4) is malformed, D146 now skips it instead of aborting. | D75 family. §F D146. |
 | **D170** | Named-NPC "flee" scripted behavior looks wrong on PC: on Silo, Ourumov breaks into a full run the instant he alerts ("Ourumov: Kill him!") rather than the N64 walk/retreat; developer reports Trevelyan behaves the same way on Cradle. **M-49 full playthrough: escalated — Cradle (`-level_51`) is "bugged out completely" from Trevelyan's behavior; the final level's scripted progression breaks. Now folded into / superseded by §F D193 (NPC AI locomotion too slow).** | **Observed, not investigated** (M-34, from a Silo playtest capture; user bug report — no fix wanted yet). Could be a genuine ailist / `chrTick` divergence, OR the D155/D156 wall-clock `deltaFrames` locomotion-anim speed-up (a catch-up spike playing the walk cycle at 2–3×). **Verify first:** capture the same beat against N64 reference footage before assuming it diverges — Ourumov may be scripted to flee. If it's real, suspect the frametiming clamp (§F D155/D156) or the Cradle-family AI path (§F D123). |
 | **D171** | Silo missile-shaft: a large translucent grey triangle sweeps across the lower frame while panning down the shaft (~3 s of the capture). Looks like a stray poly / near-plane clip fan, same family as D106 (portal near-plane min>max). | **Observed, not investigated** (M-34, Silo capture). Cosmetic, intermittent, tied to camera angle in the open vertical shaft. |
-| **D172** | Bullet-impact / blood particle spray renders magenta or cyan instead of dark red (visible on guards hit at close range on Silo). | **Observed, not investigated** (M-34, Silo capture). A channel-order / CC-mode error in the particle-sprite path (magenta = R+B, cyan = G+B) — not the D64/D120 blood-decal family (those are crash/hang + missing decals, not color). Likely a texture-format or env-color decode in `blood_animation.c` / the fast3d sprite path. |
+| **D172** | Bullet-impact / blood particle spray renders magenta or cyan instead of dark red (visible on guards hit at close range on Silo). | **Root-cause candidate found, static research done** (`docs/dev/D172-PARTICLE-COLOR-RESEARCH.md`). Particles get CC/tile state from 15 ROM records replayed via `gSPDisplayList` (`explosion.c:894`); each record contains an opcode **0xB9** that fast3d does not handle → the D146 unknown-opcode guard kills the sub-DL before the record's `G_SETCOMBINE`+`G_SETTIMG` apply → particles draw with stale state = magenta/cyan. SETCOMBINE decode itself verified correct. Verify in-game: watch console for `D146: unknown GBI opcode 0xb9` while shooting (rate-limited to 20). Fix: decode 0xB9 semantics (ginit.s missing from repo — trace gmain.s 0x80–0xBF group or infer from data) + implement in fast3d. |
 | **D178** | Objectives not listed correctly on the pre-mission briefing screen (the mission overview shown before starting a level). | **M-36 triage: the objective lines are BLANK, not wrong.** `GE_STARTMENU=10` Dam briefing renders the header fine ("OHMSS / Agent: James Bond / Mission 1: Arkangelsk / Part i: Dam / PRIMARY OBJECTIVES:") then just the bullet "a." with no text and no b/c/d. → **D143/D151 blank-text family** (`langGet()` → NULL → silent blank), *not* a propDef walk / difficulty decode. **Family B** in `docs/dev/M-36-TRIAGE.md` — find which lang bank the front-end briefing flow fails to load. Re-confirm the exact shape in a *real* briefing (the `GE_STARTMENU` boot skips real save state). Close relatives: D151 (watch objective text blank — type-35/23 `text` slot u16→u32 fix, M-28; interactive re-verify was still pending), D143 (briefing/objective text blank via `langGet` NULL), D157 (objective difficulty byte offset — could make difficulty-gated objectives appear/disappear wrongly). The pre-start briefing is a *different surface* from the in-level watch, so D151's fix may not cover it. **Next:** ask user which level + what exactly shows vs expected; compare against `docs/dev/LEVEL-OBJECTIVES.md` (regenerated post-D157); if lines are blank → D143/D151 family (`langGet` NULL guard = silent blank), if wrong objectives listed → propDef type-23 record walk / difficulty decode. |
 | **D175** | In-game stutter / brief hang during normal play — observed opening a door on Runway (mission 3, `-level_35`) and also on Surface. No backtrace captured (gdb attach missed the window; it self-recovered). | **Observed, not investigated** (user QA report). Matches known transient-hang classes rather than looking new: D155 (post-slow-load catch-up spiral — clamped), D156 (anim NaN loop — guarded, prints one-shot stderr diag if it fires), D134 (SP/DP task-done event swallowed — fixed M-22, Runway was an original victim), D147/D152 (audio `s_imLock` steal = ~2 s hiccup). Door-open specifically = new room first visible → one-off texture-import/frame spike (likely benign). **Next:** reproduce under `tools_pc/debug.ps1` with the box idle; check console for the D156 stderr diag; if it recurs, attach gdb mid-hang and pattern-match `bt` (import_texture = benign slow frame; model.c:3131 spin = D156; pthread_mutex_lock on s_imLock = D147/D152). |
-| **D176** | Surface exterior renders wrong (two co-located defects). **(a)** Sky is solid **black** — the skybox / sky gradient does not draw at all (reference: warm sunset cloud gradient). **(b)** The perimeter **tree-line backdrop renders as grey TV-static / comb interlacing** instead of snow-laden pines — the geometry is present and roughly the right silhouette but every tree texture is scrambled noise. Ground, tunnel and the dish/bunker building draw fine. | **Observed, screenshots committed** (M-35, user QA; `docs/img/bugs/d176-surface-exterior-our-build.png` vs `-reference.png`). Level is the shared Surface exterior — user reached it Dam→Surface on Agent so this is **Surface (i) `-level_36`** (confirm it also affects `-level_43`). **(a)** black sky: **M-36 partial (findings.md "D176(a)").** Env data is correct (`Sky.Clouds=1`, `CloudRGB=240,120,30`, `SkyImageId=0`); `skyRender` runs the cloud path and classifies corners correctly (switch case 12), but `skyRenderTri`/`skyRenderFull` emit nothing — not even the `env->RGB` fill shows. Not root-caused: next is probing `sub_GAME_7F097388` projected coords, verifying `skywaterimages[0]` resolves on PC (`image_bank.c` GIMG offset `0xFB4`), and a fast3d sky-tri trace. `GE_D176=1` probe shipped. **M-37: ROOT-CAUSED** — `skyRenderTri`/`skyRenderFull` build geometry *exclusively* as `G_RDPHALF_*` immediates, which `gfx_pc.cpp` deliberately no-ops (identical no-op in the PD port); fix = decode the RDPHALF tri-raster stream in fast3d (~1 session, genuine new code). **M-42: `-level_22` (Statue) confirmed a clean headless repro** — bare boot, frame ~360, upper half pure black; use it to verify the decoder. `-level_36`/`-43` intro cams face down (not a sky test without `GE_INPUTSCRIPT`). **(b)** tree/rock static: **M-36 triage — NOT the D159 family.** `texSwapAltRowBytes` is a full `#ifdef PORT` no-op (`image.c:2199`), it cannot cause this. Real cause: `port/fast3d/gfx_pc.cpp` `import_texture_*` assume `line_size_bytes == full_image_line_size_bytes` (`SUPPORT_CHECK`; rgba16's is commented out *"trips ... with a garbage size"* `:658`) → non-PoT / sub-rect tiles get a flat linear read → diagonal row shear = grey static. **Family A** in `docs/dev/M-36-TRIAGE.md`. Fix: honour `line_size_bytes` as the real source pitch. Same defect as D182(2). |
+| **D176** | Surface exterior renders wrong (two co-located defects). **(a)** Sky is solid **black** — the skybox / sky gradient does not draw at all (reference: warm sunset cloud gradient). **(b)** The perimeter **tree-line backdrop renders as grey TV-static / comb interlacing** instead of snow-laden pines — the geometry is present and roughly the right silhouette but every tree texture is scrambled noise. Ground, tunnel and the dish/bunker building draw fine. | **Observed, screenshots committed** (M-35, user QA; `docs/img/bugs/d176-surface-exterior-our-build.png` vs `-reference.png`). Level is the shared Surface exterior — user reached it Dam→Surface on Agent so this is **Surface (i) `-level_36`** (confirm it also affects `-level_43`). **(a)** black sky: **M-36 partial (findings.md "D176(a)").** Env data is correct (`Sky.Clouds=1`, `CloudRGB=240,120,30`, `SkyImageId=0`); `skyRender` runs the cloud path and classifies corners correctly (switch case 12), but `skyRenderTri`/`skyRenderFull` emit nothing — not even the `env->RGB` fill shows. Not root-caused: next is probing `sub_GAME_7F097388` projected coords, verifying `skywaterimages[0]` resolves on PC (`image_bank.c` GIMG offset `0xFB4`), and a fast3d sky-tri trace. `GE_D176=1` probe shipped. **M-37: ROOT-CAUSED** — `skyRenderTri`/`skyRenderFull` build geometry *exclusively* as `G_RDPHALF_*` immediates, which `gfx_pc.cpp` deliberately no-ops (identical no-op in the PD port); fix = decode the RDPHALF tri-raster stream in fast3d (~1 session, genuine new code). **M-42: `-level_22` (Statue) confirmed a clean headless repro** — bare boot, frame ~360, upper half pure black; use it to verify the decoder. **M-47 + read-only consolidation:** Path B draft exists (`scratchpad/sky.patch`, `skyPortRenderPoly` PORT hook — geometry+texture reach GL, two unit defects open) and the full RDPHALF wire format is now decoded (S15.1 half-packing, 8-component perspective-interpolated vertex vectors); next session is mechanical per `docs/dev/D176a-SKY-NOTES.md`. `-level_36`/`-43` intro cams face down (not a sky test without `GE_INPUTSCRIPT`). **(b)** tree/rock static: **M-36 triage — NOT the D159 family.** `texSwapAltRowBytes` is a full `#ifdef PORT` no-op (`image.c:2199`), it cannot cause this. Real cause: `port/fast3d/gfx_pc.cpp` `import_texture_*` assume `line_size_bytes == full_image_line_size_bytes` (`SUPPORT_CHECK`; rgba16's is commented out *"trips ... with a garbage size"* `:658`) → non-PoT / sub-rect tiles get a flat linear read → diagonal row shear = grey static. **Family A** in `docs/dev/M-36-TRIAGE.md`. Fix: honour `line_size_bytes` as the real source pitch. Same defect as D182(2). |
 | **D174** | "No blood effect" — user reports no visible blood when shooting guards / into surfaces. | **User QA report; likely D120, unverified.** Decals: the D120 `PointUsage[]` converter fix (M-30) was never interactively verified and only takes effect after a full sidecar regen (`d43 && d69 && d88 --regen`) — check whether the playtest build had regenerated sidecars before concluding the fix failed. Spray: D172 observed the particle spray *drawing* (wrong color, magenta/cyan) on Silo — if the user sees no spray either, that's new info (different weapon/range, or the D172 decode is worse than "wrong color"). First step: BUNKER1 firefight with regenerated sidecars; if decals still absent, instrument the `chr.c:3328` decal walk. |
 | **D173** | Third-person Bond model (the player-representing figure shown at level start) spawns too high — floats well above the ground "a lot of the time" while the actual player spawn is correct. Same symptom on the Cuba end credits: JB stands ~6 ft in the air above Natalya. | **Confirmed still present across the full 21-level playthrough (M-49).** **Observed, not investigated** (user QA report). D75 animated-model family but a *position* defect, not absence — M-33 confirmed the gun-barrel Bond renders fine upright. Suspects: (a) intro/credits puppet chr spawn position vs the model's base transform; (b) anim root-motion accumulation (`modelSetAnimFrame2WithChrStuff`, D156 area) offsetting the rendered joints above the body origin; (c) a `coord3d`/packed-float decode in the intro camera/model setup. "Player spawning is OK" localises it to the render-side model, not `g_CurrentPlayer` state. |
 | **D182** | SELECT FILE screen degrades after navigating away and back (main menu → file select, or backing out of file select and re-entering). On the fresh screen the 007 gun-barrel spiral / Bond silhouette renders behind the file boxes; after a round-trip **the Bond image stops drawing entirely** and the whole background gains the **comb / interlacing** artifact (horizontal line scramble). File boxes, text and the Copy/Erase icons still draw. | **Observed, screenshot committed** (M-35, user QA; `docs/img/bugs/d182-file-select-backout-20260902.png`). Two symptoms, likely linked: **(1)** background 3D image stops rendering after re-entry → a front-end model/DL whose `render_pos` / segment binding is only valid on first construction (D149 / D75 `constructor_menuXX` family — the dossier/wallet models have the same "renders once" behavior). **(2)** interlacing = **M-36 triage: Family A**, the `import_texture_*` `line` vs `full_image_line` shear (see D176(b) / `docs/dev/M-36-TRIAGE.md`) — **not** the D159 `texSwapAltRowBytes` path (that is a full PORT no-op). Open question: why only *after* a round-trip — first import may land `line == width`, re-import may not, or the tile descriptor is stale on re-entry. Repro: `GE_STARTMENU` to file-select, back out with ESC/B, re-enter; `GE_DTEX` on the spiral texture across both visits. Shares defect (2) with D176(b). |
 | **D197** | Character face/head textures wrap wrong — the face texture repeats around the side of the head "and continues weird" instead of clamping to the front. Seen on **Silo** (M-49 playtest), intermittent ("sometimes"). Reads as **`G_TX_CLAMP` not honoured** for the character-skin tile in fast3d (→ `GL_REPEAT`, so the face UV region tiles around the skull), or wrong `shifts`/`shiftt` / LOD-tile selection on the head texture, or the D167 non-PoT wrap-period issue (head textures are often non-PoT) hitting skinned models. | **Observed, not investigated** (M-49, user bug report — needs a capture + which chr/level). Distinct from D176(b)/D182(2) (those are *bg wall* pitch shear). Related: RC3/D167 (`Video.WrapFix`, non-PoT wrap period) + the `texWriteTileLods` `shifts=shiftt=lod` note in findings §F "D176(b) → 4. candidate 2". First checks: does `gfx_pc.cpp` map N64 `cms/cmt` `G_TX_CLAMP` → `GL_CLAMP_TO_EDGE` for character DLs; is the head tile getting the base tile vs an LOD tile (D107); try `Video.WrapFix=1` on a repro. |
 | **D195** | Transparency / alpha-blended surfaces render wrong — reported on **Control** (Severnaya bunker basement — Natalya's console room; heavy on glass partitions and the translucent projected/holographic wall displays). Exact failure mode not yet pinned by the reporter (M-49 playtest): candidates are alpha-blended geometry drawing fully opaque, translucent panels drawing invisible, or draw-order/sort so translucent surfaces occlude what's behind. | **Observed, not investigated** (M-49, user bug report — needs a `GE_PCDUMP` capture + which surfaces). fast3d render-mode / combiner path. Same neighborhood as D161 (CI8 tile + `G_TT_NONE` → garbage), D172 (particle-sprite channel order), D176(b) (texture pitch shear) — but this is a *blend/alpha* defect, not a texture-decode one. Note D128 already touched Control's `specialportalarray` (portal struct stride) — check whether the affected surfaces are portal-adjacent. First checks: does `gfx_pc.cpp` honour `G_RM_*` XLU render modes + `G_AC_THRESHOLD`/`G_CC` alpha for these DLs; is `gDPSetRenderMode` `w1` being parsed (cf. findings §F "zbuf-clear w1 scribble"); is Z-write-vs-blend ordering right for XLU surfaces. Get the reporter to say: opaque-where-should-be-clear, invisible, or wrong edges? |
-| **1P weapon viewmodel** | In-level first-person weapon models don't draw at all (no gun visible while playing). | Already documented — **AUDIT-M6 #5** (`docs/dev/AUDIT-M6-player-offsets.md`, "prime suspect") + §F D115 "still open (MED)"; M-8 handoff listed it NOT STARTED with a plan: instrument `gunfire.c:600-661` setup + `field_87F` gating first, then check `weaponModel.render_pos` arena lifetime and `weaponRwPool[192]` sizing. Note M-32b's "render_pos/dynAllocate RULED OUT" probe was the **front-end gun-barrel** path (`title.c`), not this in-level path — candidate #5 still stands. Distinct from the watch-page "dark/faint weapon model" (D75, D141 note). |
+| **1P weapon viewmodel** | In-level first-person weapon models don't draw at all (no gun visible while playing). | **Static research done — `docs/dev/VIEWMODEL-RESEARCH.md`.** Ruled out: arena lifetime (setup + render same frame; `dynSwapBuffers` only at frame end), word-index math (D52 `u32*` pool), segment/render_pos mechanism (bodies + watch-menu weapon models render through it). Ranked suspects: **#1 `field_87F` gate** — the `(Gun_hand_without_item(h) == 0)` clear-term (`gun.c:812`) reads as "hide when holding an item"; a PC init divergence in `hand_item`/`field_2A44`/`hand_invisible` yields exactly this symptom (render loop `continue`s at `gunfire.c:1537`). **#2** `weaponRwPool[192]` capacity vs PC-wide rw records (no bounds check; DEBUG print's 32-word threshold is stale N64). **#3** stale `copy_of_body_obj_header` → NULL `RootNode` → `subdraw` silent no-op (`model.c:5326`). Next: one `GE_DVM=1` probe in the setup block triages all three in a single BUNKER1 run. |
 
 ## Resolved (for reference)