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arcattackandClaude Opus 4.8 1cd57ade85 context-system: bootstrap the progressive-context expert knowledge base (foundation)

Adapt the spark-lesson / expert-seed.md progressive-context pattern to the bt411 port:
a thin router + context/*.md knowledge graph so the 2236-line CLAUDE.md's deep knowledge
loads on-demand instead of every session.

NON-DESTRUCTIVE foundation pass (live CLAUDE.md unchanged; proposed router is a draft):
- reference/glossary.yaml        -- ~45 terms (engine/formats/scene/reconstruction)
- context/decomp-reference.md    -- the quantitative hub: resource types, ClassID map,
                                    mech offsets, damage delivery, weapon constants, env gates, tools
- context/reconstruction-gotchas.md -- the 12 systemic bug classes (conventions/DO-NOT hub)
- context/bgf-format.md          -- geometry format + CONN/PCONN + LOD-sqrt3 + ramp shading
- context/gauges-hud.md          -- the gauge/MFD system (the just-completed wave)
- context/open-questions.md      -- deferred systems + get-from-Nick
- context/_ROUTER-DRAFT.md       -- the proposed slim CLAUDE.md (identity, protocols,
                                    quick-lookup, evidence tiers T0-T4, conventions, structure)
- phases/phase-01-context-restructure.md -- design + migration plan + status

docs/*.md ledgers stay as the DETAILED logs; context/*.md are the curated digests that
route into them. Remaining: ~10 topic files (project-overview, subsystems, combat-damage,
rendering, locomotion, wintesla-port, build-and-run, ...) then the CLAUDE.md swap.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

2026-07-07 22:06:53 -05:00

3.8 KiB

Raw Blame History

id, title, status, source_sections, related_topics, key_terms, open_questions

title

status

source_sections

related_topics

key_terms

open_questions

bgf-format

BGF Model Format (DIV-BIZ2 geometry) + the render gotchas

established

docs/BGF_FORMAT.md (full spec); CLAUDE.md §5, §10 render-fidelity notes

asset-formats

rendering

decomp-reference

BGF

DIV-BIZ2

PMESH

CONN

PCONN

LOD

material-ramp

SV_SPECIAL

Replacement-LOD selection for NON-additive multi-LOD models (hot-spot/reference semantics)

BGF Model Format

.BGF = DIV-BIZ2 little-endian nested Tag-Length-Value geometry. Full byte-level parsing spec (verified against all 1275 content .BGF files) lives in docs/BGF_FORMAT.md — this topic captures the structure + the hard-won gotchas that cost real debugging. Loader of record: engine/MUNGA_L4/bgfload.cpp (game-callable via LoadBgfFile); standalone reference reader DivLoader/VGCDivLoader.cpp. Tag names: dsys/PFBIZTAG.H.

Structure

OBJECT → LOD → PATCH (geogroup) → PMESH. Interleaved float32 verts; QUAD faces (must triangulate [a b c][a c d]); materials referenced by library:material name (resolved against the map's .BMF libs). Damage/articulation are name-driven via SV_SPECIAL (0x2037) dz_* tokens, not stored geometry. [T1]

Indices — the CONN/PCONN story (two corrections)

A PMESH carries faces in CONNECTION_LIST (0x0047) and/or PCONN_LIST:

CONNECTION_LIST is a FLAT TRIANGLE LIST (3 indices/face) — NOT "one polygon, fan-triangulate" (the original doc was wrong; fan-triangulating turned buttec's 115 tris into 341 fan-garbage). Corpus-verified: ALL 3488 CONN chunks have n%3==0. [T2]
CONN and PCONN COEXIST — a pmesh can carry quads/hexes in PCONN PLUS loose triangles in CONN. 370 of 841 GEO models had mixed pmeshes silently dropping their CONN triangles until both were processed always (the "turret base missing panels" bug). ppf=6 hexagons exist. [T2]

LODs — the √3 decode

Each LOD chunk carries a 0x2046 header = [near..far) viewing band. The board selected the LOD whose band contains the camera distance.

√3 range decode: every stored band value is the authored euclidean distance ÷ √3 (92% of the corpus is exactly nice-number/√3; hand-conversion typos prove it). Multiply parsed bands by √3 (kLodRangeScale=1.7320508). [T2]
Metric = the instance-transformed OBJECT ORIGIN distance, ONE shared d for all LODs of an object (a bounding-sphere-SURFACE metric desyncs sibling bands — wrong). [T2]
ADDITIVE_LODS (object-level SV_SPECIAL token, 135 pod BGFs — all arena structures): at eye distance d, EVERY LOD with d < OutDist draws (near detail ADDS onto coarser massing). Non-additive keep first-LOD-only (the 2007 engine's own behavior). [T2]
PUNCH (patch-level SV_SPECIAL): cutout geogroups — black texels = HOLES (alpha-test in the opaque pass). Coplanar shells inside one LOD z-fight → depth-bias by submission ordinal. [T2]

Shading model (from libDPL DPLTYPES.H)

Shading is selected PER-GEOMETRY by vertex type:

No-normal geometry (XYZ_UV / XYZ_RGBA_UV: mesas/ground/sky/buildings/mech, WHITE baked verts) is UNLIT, colorized by the material's 2-endpoint RAMP (see material-ramp).
Normal-bearing geometry (XYZ_N_UV: ~150 vehicle/missile files) is LIT by the map light.
Applying the ramp to lit geometry = the "dusty white blobs" bug — gate on hasNormals. [T2]

Skeleton assembly

A mech is not one BGF — it's a .SKL skeleton (a DCS tree of joints) whose each joint's Object=part.bgf is loaded + posed, then animated by .ANI clips. See asset-formats / locomotion for skeleton + animation. [T1]

Key Relationships

Detailed spec: docs/BGF_FORMAT.md.
Consumed by: rendering (the D3D9 draw path), locomotion (skeleton parts).
Related: asset-formats (BMF/BSL/SKL/ANI), decomp-reference.

3.8 KiB Raw Blame History