docs(D172): ROOT CAUSE FOUND + FIXED — gfx_lod_tile_offset collapse; findings D172 row + index

docs/dev/D172-PARTICLE-COLOR-RESEARCH.md

@@ -1,7 +1,32 @@
-# D172 — particle/flares wrong color (magenta/cyan blood): static research + root-cause candidate
+# D172 — particle/flares wrong color (magenta/cyan blood): ROOT CAUSE FOUND + FIXED (M-82)
 
 Symptom (user-reported, GRAPHICS-BACKLOG line 31): bullet impacts / flares / blood spatter
-render magenta/cyan instead of dark red. Static audit done; one strong root-cause candidate
+render magenta/cyan instead of dark red.
+
+## TL;DR (M-82)
+
+**Root cause:** `gfx_lod_tile_offset()` (`gfx_pc.cpp`) returns `0` unconditionally on
+the `!gfx_detail_textures_enabled` path (a D107 blurry-ceiling fix — and
+`port/src/video.c:225` sets that flag `false` at startup). Particle draws use
+`G_CC_INTERFERENCE` (`TEXEL0 * TEXEL1`) with tile 0 = IA8 smoke @ TMEM 0 and
+tile 1 = RGBA16 fire @ TMEM 0x188 — but with the offset pinned to 0, **texunit 1
+samples the smoke texture too**. `smoke * smoke` through the rest of the combine
+= the magenta/cyan. Confirmed by the `GE_D172` probe on a user Silo firefight:
+40/40 particle tris logged `cfg1[tile=1 tmem=392 fmt=RGBA]` but
+`SAMPLED1=tile0(tmem=0 fmt=IA)`.
+
+**Fix (`gfx_pc.cpp` `gfx_lod_tile_offset`):** `return rdp.tex_lod ? 0 : i;` —
+fold to the base tile only when LOD is actually active (D107's mip case,
+`tex_lod=1`, unchanged); a genuine non-LOD 2-texture combine now gets tile `i`.
+`bunker1` verify PASS (the D107 repro level). Committed on PR #34. **Owed: an
+in-game eyeball that blood/sparks now read dark red.**
+
+The 0xB9 / cycle-type false trails and the probe design are kept below for the
+record.
+
+---
+
+Original note (superseded): Static audit done; one strong root-cause candidate
 with a cheap in-game verification. **No code changed.**
 
 ## 1. How particles get their color state (mechanism)

docs/dev/GRAPHICS-BACKLOG.md

@@ -18,7 +18,7 @@ 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). | **M-82: 0xB9 root cause WITHDRAWN** (`docs/dev/D172-PARTICLE-COLOR-RESEARCH.md` §4). 0xB9 = `G_SETOTHERMODE_L` in this non-F3DEX2 build (`= G_IMMFIRST-6`), already handled by fast3d as `gsDPSetRenderMode`; `-level_09` sustained-fire run logged **zero D146 aborts**. **Cycle-type also ruled out (M-82):** the real records (`assets/oddtextures.c` `globalDL_0x078…`) *do* `gsDPSetCycleType(G_CYC_2CYCLE)`, and a `GE_D172=1` probe confirms fast3d applies it (particle combine `fc26a004` logged at `cycletype=2CYC`). Bug is the **`G_CC_INTERFERENCE` two-tile combine / TEXEL1 path** — record binds tile 0 (IA8 smoke) × tile 1 (RGBA16 fire @ tmem 0x188); magenta/cyan = TEXEL1 tmem-offset / RGBA16 decode / LOD-tile fault. Needs a display capture. Probes shipped (`GE_D172=1`, inert). Detail: `D172-PARTICLE-COLOR-RESEARCH.md` §5–6. |
+| **D172** | Bullet-impact / blood particle spray renders magenta or cyan instead of dark red (visible on guards hit at close range on Silo). | **M-82: ROOT CAUSE FOUND + FIXED (PR #34).** `GE_D172` probe on a user Silo firefight: 40/40 particle tris configure tile 1 = RGBA16 fire @ tmem 392 but fast3d **samples tile 0 (smoke) for both texunits** — `gfx_lod_tile_offset()` returns 0 unconditionally (D107 blurry-ceiling fix; `video.c:225` disables `gfx_detail_textures_enabled`). `G_CC_INTERFERENCE` = `smoke*smoke` → magenta/cyan. Fix: `return rdp.tex_lod ? 0 : i` — only fold to base tile for real LOD/mip draws. (0xB9 + cycle-type were both false trails, ruled out earlier in M-82.) **Owed: in-game eyeball — blood should be dark red.** Detail: `D172-PARTICLE-COLOR-RESEARCH.md`. |
 | **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. **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`). **M-82: PR #18 rebased onto main + Defect-1 fix applied** — cloud tile is `s_skywaterimages[0]` = 64×64 IA8; the patch's `tc = S·32` scale is correct (matches GE's `width<<5` idiom, `glass2.c:678`), the bug was `(s16)` overflow on the ±20k-texel horizon S/T; fix = per-primitive phase-fold to the 64-texel period (`sky.c` `skyPortRenderPoly`, `#ifdef PORT`). Builds clean, no crash (bunker1/statue/surface1 verify PASS). **Unverified visually** — owed: one `-level_22` screenshot (see `D176a-SKY-NOTES.md` "verification ask"). Defect 2 (horizon-band coverage / straddling tris) still open → adaptive tessellation. **(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). |

docs/dev/findings-index.csv

@@ -45,6 +45,7 @@ D178,FIXED,Pre-mission briefing screen:,FIXED (M-36) — high confidence
 D175,?,In-game stutter / brief hang during normal play (user QA report):,"Observed, not investigated"
 D176,OPEN,"Surface exterior renders wrong (-level_36), two independent defects.","(a) root-caused, fix owed / (b) open"
 D177,FIXED,Ladders non-functional —,FIXED (M-36) — high confidence; interactive climb test owed
+D172,FIXED,"Bullet-impact / blood / spark particles render magenta or cyan instead of dark red (M-82, ROOT CAUSE FOUND + FIXED).",FIXED (port/fast3d/gfx_pc.cpp gfx_lod_tile_offset):
 D174,?,"""No blood effect"" (user QA report).",Observed; first step = BUNKER1 firefight with regenerated sidecars
 D183,OPEN,"M-36 Family A (""texture line/pitch shear"") is DISPROVEN for the Surface repro (-level_36).",Hypothesis DISPROVEN + diagnostics shipped; D176(b)/D182(2) still OPEN
 D173,?,Third-person Bond model spawns too high (user QA report):,"Observed, not investigated"

docs/dev/findings.md

@@ -419,6 +419,7 @@ covers D24–D69; the log continues in §H (D32 procedure, D70–D121).
 | D175 | **In-game stutter / brief hang during normal play** (user QA report): opening a door on Runway (`-level_35`, mission 3) and also observed on Surface. Self-recovered; no backtrace captured. Likely one of the known transient-hang classes (D155 catch-up spiral / D156 anim NaN loop / D134 task-done event / D147-D152 audio-lock steal) or a benign new-room texture-import frame spike on door open. See `GRAPHICS-BACKLOG.md` D175 for the gdb pattern-match sheet. | Observed, not investigated |
 | D176 | **Surface exterior renders wrong (`-level_36`), two independent defects.** **(a)** sky solid black — env data is correct (`Clouds=1`, warm `CloudRGB`), the cloud-sky path runs, but `skyRenderTri`/`skyRenderFull` emit only `G_RDPHALF_*` immediates which `gfx_pc.cpp:2901` deliberately no-ops → **root-caused M-37** (see "D176(a) — M-37 UPDATE"); fix = decode the RDPHALF sky-tri stream in fast3d. **(b)** cliff/rock walls = grey diagonal static — NOT a texture decode bug (D183 disproved the shear hypothesis, 0/166 loads strided); re-scope from ROM ground truth of the wall texnum (M-37: inconclusive, leaning tiling-density). See `GRAPHICS-BACKLOG.md` D176. | (a) root-caused, fix owed / (b) open |
 | D177 | **Ladders non-functional — progression blocker (user QA report) — FIXED (M-36).** Not the input path and not the ladder state machine: `MoveBond` gates the ladder-collision path on `stanGetLocusCount(&curLocus)`, which was pinned at 0 on PC. `stanCheckLinkedSpecialTile` writes the LADDER signal via raw `outFlags[1] = 1` into a `struct StandTileLocusCallbackRecord` whose first member `s32 *rooms` is pointer-widened on PC → `[1]` is the high half of `rooms`, and `count` (moved +4→+8) is never written. Compounded by `curLocus` being declared as the 8-byte placeholder `move_bond_temp_struct` (too small for the widened record) and a `(s32)coords` pointer-truncation AV waiting in `stanGetMoveBondCollisionTiles`. **Fix:** `#ifdef PORT` — write record fields by name, declare `curLocus` as the real struct, `PORT_PTRADD` for the truncating cast (`src/game/stan.c`, `src/game/bondview2.c`; no game logic). Full detail: §F "D177". | **FIXED (M-36)** — high confidence; interactive climb test owed |
+| D172 | **Bullet-impact / blood / spark particles render magenta or cyan instead of dark red (M-82, ROOT CAUSE FOUND + FIXED).** Particle billboards (`explosion.c` `explosionRenderPart`, `gSPVertex`+`gSP2Triangles`) take their CC/tile state from ROM state records replayed just before them (`g_ExplosionDisplayLists[]` = `assets/oddtextures.c` `globalDL_0x078..`). The dominant record sets `gsDPSetCycleType(G_CYC_2CYCLE)` + `gsDPSetTextureLOD(G_TL_TILE)` + `gsDPSetCombineMode(G_CC_INTERFERENCE, G_CC_MODULATEIA2)` and binds **two** tiles: tile 0 = IA8 "smoke" @ TMEM 0, tile 1 = RGBA16 "fire" @ TMEM 0x188. `G_CC_INTERFERENCE` cycle-0 = `TEXEL0 * TEXEL1`. **fast3d's `gfx_lod_tile_offset()` returns `0` unconditionally** on the `!gfx_detail_textures_enabled` branch — a D107 fix for GE's mip textures (whole chain loaded in one LOADBLOCK at TMEM 0; `port/src/video.c:225` sets the flag `false`). So texunit 1's sampled tile = `first_tile_index + 0` = tile 0 → **TEXEL1 samples the smoke texture, not fire** → `smoke * smoke` → wrong colour. Two earlier M-82 candidates were false trails: (1) "0xB9 unhandled → D146 abort" — 0xB9 is `G_SETOTHERMODE_L` in this non-F3DEX2 build, handled; zero D146 aborts in a sustained-fire run. (2) "records never set 2-cycle" — they do (`0xBA`), and fast3d applies it (probe-confirmed `cycletype=2CYC`). **Probe evidence (`GE_D172=1`, user Silo firefight, `d172_silo.log`):** 40/40 particle tris → `cfg1[tile=1 tmem=392 fmt=RGBA siz=16b]` but `SAMPLED1 = tile0 (tmem=0 fmt=IA)`, `tex_lod=0`. | **FIXED (`port/fast3d/gfx_pc.cpp` `gfx_lod_tile_offset`): `return rdp.tex_lod ? 0 : i;`** — fold to the base tile only when LOD is actually active. D107's mip case (`tex_lod=1`, blurry ceilings) unchanged; a genuine non-LOD 2-texture combine now samples tile `i`. `bunker1` verify PASS (the D107 repro level), no framediff regression. PR #34. **Owed: in-game eyeball — blood/sparks should read dark red.** Env-gated `GE_D172` probes left in tree (`#ifdef PORT`, inert). |
 | D174 | **"No blood effect" (user QA report).** Likely the unverified D120 decal fix: `d43_emit.py` now emits the opcode-0x18 `PointUsage[]` chain, but it was never interactively verified and requires a full sidecar regen to take effect (`debug.ps1` does not regen). Spray path is D172 (draws, wrong colour) — total absence would be new. See `GRAPHICS-BACKLOG.md` D174. | Observed; first step = BUNKER1 firefight with regenerated sidecars |
 | D183 | **M-36 Family A ("texture line/pitch shear") is DISPROVEN for the Surface repro (`-level_36`).** The importers' pitch assumption is real but never fires there; the Surface cliff "grey static" is not a shear. Full evidence + what the walls actually are: §F "D183" below. A defensive, provably-no-op de-stride landed in `import_texture()` anyway (covers the `gfx_dp_load_tile` case the `SUPPORT_CHECK`s assert against), plus `GE_DTEX` STRIDED marker + `GE_TEXRAW` raw-source dump. | Hypothesis DISPROVEN + diagnostics shipped; D176(b)/D182(2) still OPEN |
 | D173 | **Third-person Bond model spawns too high** (user QA report): the player-representing figure at level start floats well above the ground "a lot of the time" while the actual player spawn is correct; same on the Cuba end credits — JB ~6 ft in the air above Natalya. D75 animated-model family but a *position* defect, not absence (M-33: gun-barrel Bond renders fine). Suspects: intro/credits puppet chr spawn position vs model base transform; anim root-motion accumulation (`modelSetAnimFrame2WithChrStuff`, cf. D156); packed-float `coord3d` decode in intro setup. "Player spawning OK" localises it to the render-side model, not `g_CurrentPlayer`. See `GRAPHICS-BACKLOG.md` D173. | Observed, not investigated |