bcdfa — The Big Container

bcdfa — The Big Container

bcdfa (197,894 bytes) is the game’s mixed container. It is not a flat run of RLE streams — some blocks are RLE-compressed, some are raw. This is the single most important thing to know about it: locate blocks by marker string, never by blind stream-splitting from offset 0.

It’s loaded by bcdft‘s own code (OpenBcdfaFile, S_1 +0x1DBD2), which reads a real 13-entry container directory at S_1 +0x1DC54 — the same 3-word (offset, size, compressed) shape as the tilesets’ chunk directories. That directory sums to bcdfa’s exact file size, 13/13, zero deviation.

What’s inside

Offset	Size	Content	Status
0x00000	18,932 B	UI panel bank — 32 records, 15 named	Solved
0x06F4D	28,846 B	Effect sound bank — raw signed 8-bit PCM	Solved
0x0DFFB	16,576 B	BCSPEED.GFK — 73 effect sprites (16×16, mask+6bpp)	Solved
0x10779	4,288 B	Message-log font (four fonts, all code-confirmed)	Solved
0x111E1	34,340 B	UI / Automap resource bank — 13 records	Mostly solved
0x15F8D	20,195 B	BCSPEED.EFF — 95 effect particle scripts (raw)	Solved
0x1AE70	1,308 B	BCSPEED.PRG — 34 uncompressed animation scripts	Solved
0x1B5B3	75,600 B	Item icon bank — 175 icons (24×24, 6bpp, no mask)	Solved
0x270C4	31,388 B	Dungeon-floor item sprites — 147 = 49 items × 3 depths	Solved
0x2D05E	13,224 B	Chest armour paperdoll — 19 × 32×29, 6bpp	Solved
0x2FE5C	2,160 B	Item icons — 5 more (24×24)	Solved
0x300C2	1,092 B	Throwing-items projectiles — Arrow + Dagger × 3 depths × 2 facings	Solved
0x036FD	—	Large equipment-panel art — 7 records (48-px rows)	Solved

The UI panel bank (0x00000)

32 records, 15 named, every one a 7-plane masked sprite (stencil + 6 EHB colour). The named records were confirmed against the DOS port’s clipper.clp:

• as_stats — the class LV:/AC: stat panel
• face_square — the portrait placeholder frame
• gem_stone — the twin-gem ring-slot graphic
• options — the Save/Rest buttons
• up_arrows — the movement compass
• ghost — a 50% black stipple (DOS’s Ghost)
• page_1–page_5, pressure_plate_1/2_up/down

BCSPEED — the spell effects

bcdfa holds three related “BCSPEED” banks that together implement the game’s spell/projectile effects:

1. .GFK — one RLE stream at +0x0DFFB, decoding to 16,576 B = 16 records. Each record is 12-byte name + BE count + count×224, and each 224-byte frame is a 16×16 sprite in 7 planes (mask + 6bpp EHB). 73 frames total — bee, stars, fireballs, ice burst, flames, fly, skull, serpent, bolts.
2. .PRG — uncompressed, 34 records of name + BE count + count×3.
3. .EFF — 95 effect particle-emitter scripts (raw), tying the GFK sprites to the PRG movement scripts.

All three were confirmed 100% against the DOS port’s clipper.clp spell-effect atlas (73 frames, same order, 100.000% silhouette agreement).

Item icons (+0x1B5B3 / +0x2FE5C)

180 item icons in two RLE streams: 175 at +0x1B5B3, 5 at +0x2FE5C. Each is 24×24 @ 6 sequential bitplanes with no mask plane — the only Black Crypt sprite format without one — 432 bytes per record. Confirmed three ways: the whole bank is byte-for-byte resident in chip RAM at $7D918 in three savestates; the DOS port holds the same 180 icons in the same order with 100.000% silhouette agreement; and 13 in-game placements match pixel-exactly.

Dungeon-floor item sprites (+0x270C4)

147 sprites = 49 items × 3 view depths. Pixels are one RLE stream (31,388 bytes); geometry comes from a 147 × 10-byte blit-descriptor table in decompressed bcdft S_1 +0x271B6. Variable per-sprite geometry (16–80 px wide, 1–26 rows), 7 planes (mask + 6bpp EHB), packed back to back. Verified 100.000% against 43 placements in 10 real screenshots.

The four fonts

The chunk at +0x10779 is four fonts, not two:

• Region A — the in-dungeon message-log font, 64 glyphs, 8×8, 1bpp.
• Region B — a micro font, 59 glyphs, 4×5, 1bpp.
• Regions C+D — a big font, mask + colour, 59 glyphs, 8×8, 6bpp masked.

All four are code-confirmed via their consumer routines in the decompressed bcdft image.

Sound, projectiles, and the rest

• Effect sound bank (0x06F4D) — 10 raw signed 8-bit PCM samples, byte identical to 14 DOS clipper.clp sound entries.
• Throwing projectiles (0x300C2) — Arrow + Dagger at 3 view depths × 2 facings (12 records, 7-plane masked), 100% DOS agreement.

The open bits

Most of bcdfa is solved. The remaining unclassified ranges (a heterogeneous multi-record UI/text bank inside the 0x111E1 chunk) are tracked on the status page.