# Havoc file formats (reverse-engineered)

All offsets/sizes verified against the retail data set (Reality Bytes, Inc., 1995).

## Binaries

| File | Type | Notes |
|---|---|---|
| `HAVOC.EXE` | PE32 i386, GUI | Imports `DDRAW`, `DSOUND`, `WINMM`, `WSOCK32`, `GDI32`, `USER32`, `KERNEL32`. **No Direct3D** — 3D is a software rasterizer drawing into a DirectDraw surface. Contains a CD-presence check ("...Extra Player CD..."). |
| `LAUNCHER.EXE` | PE32 i386, GUI | Front-end menu (see `havoc_9` screenshot). |
| `SETUP.EXE` | PE32 i386, GUI | Config/setup. |
| `DIRECTX/` | DX5-era | Ships 16-bit `DSETUP16.DLL`/`DDRAW16.DLL` — the 16-bit installer path is what breaks on 64-bit Windows, not the game itself. |

## `.FF` — "FlashFile" archive  ✅ implemented in `tools/ff_extract.py`

Used by `MUSIC.FF`, `SOUND.FF`, `OBJECTS.FF`, `INTRFACE.FF`. Built by the bundled DOS tool
`FFCREATE.EXE` (found inside `MUSIC.FF`/`SOUND.FF`).

```
uint32  file_count                      (little-endian)
repeat file_count:
    uint32  absolute_offset             (little-endian, from start of .FF)
    char[]  name                        (NUL-terminated, variable length)
<concatenated payloads>                 entry size = next_offset - this_offset
```

Notes:
- The table may contain a trailing empty-name entry — skip it.
- Entry payloads are raw and self-describing (e.g. `RIFF`/`WAVE`, `MZ`, bitmaps).

### Archive contents

| Archive | Count | Entry kinds |
|---|---|---|
| `MUSIC.FF` | 116 | `WAVE<id>.DAT` PCM segments, `PLST<id>.DAT` playlists, `FFCREATE.EXE` |
| `SOUND.FF` | 65 | `WAVE<id>.DAT` sound effects, `FFCREATE.EXE` |
| `OBJECTS.FF` | 526 | `ASND<id>.DAT` (enemy/pickup models + object sounds — format TBD) |
| `INTRFACE.FF` | 547 | `BitB<id>.dat` headers, `BitR<id>.dat` rasters, `XPAL<id>.dat` palettes, `STR#<id>.dat` string tables, `RTbl<id>.dat` remap tables, `xpXl<id>.dat` palette variants |

## Music: `WAVE` segments + `PLST` playlists  ✅

- `WAVE<id>.DAT` — standard `RIFF`/`WAVE`, PCM **mono, 22050 Hz, 8-bit**.
- `PLST<id>.DAT` — a song = an ordered sequence of WAVE segments. **Payload is big-endian**
  (note: the `.FF` table around it is little-endian — mixed by design):

```
uint16  segment_count        (big-endian; how many WAVE segments belong to this group)
uint16  step_count           (big-endian)
uint16[step_count]  sequence  (big-endian; 1-based segment index)
```

Segment resolution: a playlist named `PLST<id>` has base id = `int(id, 16)`; **step value N
maps to wave id `base + N - 1`** (e.g. `PLST07D1` step 2 → `WAVE07D2`). Concatenating the
referenced segments' PCM reproduces the song exactly (verified by ear).

## `INTRFACE.FF` bitmap system  ✅ implemented in `tools/ff_extract.py`

All entries share a 4-digit hex ID that links related assets (e.g. `797C` = main menu):
`BitB797C.dat` (dimensions) + `BitR797C.dat` (pixels) + `xpal797c.dat` (palette) + `STR#797C.dat` (strings).

### `BitB<id>.dat` — bitmap header (4 bytes)

```
uint16  width   (big-endian)
uint16  height  (big-endian)
```

### `BitR<id>.dat` — raw bitmap raster

Raw 8-bit palette-indexed pixels, row-major, `width * height` bytes total. No header.

### `XPAL<id>.dat` / `xpal<id>.dat` — palette (768 bytes)

256 RGB triplets, 8-bit per channel (NOT 6-bit VGA). One palette per screen/sprite group.

**Critical runtime patch:** the game engine always forces palette index 2 to `(0, 0, 0)` black
at runtime. The stored XPAL files may contain any value there (often `#e78484` salmon from the
development environment). Any renderer must override index 2 to black after loading. Index 0
and 1 are the transparency/key color (`#ff00ff` magenta in most palettes).

**Discovery method:** comparing `XPAL7A12` (correct black background) vs `XPAL7A1C` (wrong
salmon background) revealed only 3 differing entries out of 256 -- indices 0, 1, and 2.

### `STR#<id>.dat` — string table

Length-prefixed strings for the screen's UI labels. First byte = string length, then UTF-8
text. Example: `STR#797C` contains all main menu button labels and the copyright notice.

Two special-purpose string tables live in `INTRFACE.FF` at fixed IDs:

| ID | Content |
|---|---|
| `7D02` | Pickup banner text -- all item and weapon pickup notification strings |
| `7D03` | HUD active weapon name display strings |

See `docs/WEAPONS.md` for the complete weapon list derived from these tables.

### Identified screens (640x480 full-screen bitmaps)

| ID | Content (from STR# strings) |
|---|---|
| `797C` | Main menu |
| `79E0` | Network options |
| `79AE` | Load/save game |
| `7A44` | Settings menu |
| `7A4E` | Sound/music settings |
| `7A58` | Graphics settings |
| `7A62` | Keyboard settings |
| `7A6C` | Joystick settings |
| `7ADA` | Info/help |
| `7A12` | Network client/server status |
| `79F4` | Network client options |
| `79FE` | Network server options |

### Identified sprites

| Size | Count | Content |
|---|---|---|
| 640x480 | 32 | Full-screen menu/UI backgrounds |
| 512x236, 512x230, 512x218 | 3 | Cockpit windshield frames (color variants) |
| 428x196 | 12 | Vehicle selection screens with 3D-rendered thumbnails |
| 104x432 | 3 | Cockpit side panel strips |
| 420x46, 228x46 | 29 | Button/UI strip elements |
| 48x48 | 57 | Vehicle HUD icons (monochrome green, multiple vehicles/angles) |
| 18x18 | 13 | Small UI icons |

## World data (`WORLDS/`) — TODO (3D terrain)

Per-level sets `<NN>` = 01..06. Six worlds confirmed from EXE string table + player memory:

| File prefix | World name | Biome |
|---|---|---|
| `LAND01xx` | Badlands | Desert |
| `LAND02xx` | Fallout | Ice/Snow |
| `LAND03xx` | Tyrak | Alien |
| `LAND04xx` | Wasteland | Desert (harder) |
| `LAND05xx` | Malterra | Ice (harder) |
| `LAND06xx` | Overlord | Alien (harder) |

Level suffix codes within each world: `01`=Level 1, `02`=Level 2, `03`=Level 3, `04`=Boss, `0B`=Bonus.
Network variants use `0N`, `1N`, `2N` prefixes for the three biomes at Easy/Medium/Hard.

Music track ID is stored at **offset 18 as big-endian uint16** in each `LAND*.DAT` file.

| Pattern | Guess | Status |
|---|---|---|
| `MAP<lvl>.MAP` | tile/heightmap grid, 1 byte per cell | layout confirmed (byte grid); dims TBD |
| `LAND<lvl>.DAT` | terrain geometry/tile defs | TBD |
| `GRAFIX0N.DAT` | 64x64 texture tilesets | ✅ cracked, see below (`tools/grafix_extract.py`) |
| `STUF<lvl>.DAT` | entity placement (contains `Item` records) | TBD |

### `GRAFIX0N.DAT` — texture tileset  ✅ implemented in `tools/grafix_extract.py`

Big-endian (Mac-origin data, byte-swapped by the in-game loader at VA `0x444db0`).
`GRAFIX00.DAT` = 29 graphics: an explosion sprite (id 901, 8 frames), a smoke sprite
(id 911, 8 frames), and 27 single-frame 64x64 structure/wall textures (ids 8001-8028:
metal panels, hazard stripes, warning bars, arrows, circuit patterns).

```
Header:
  0x00  8 bytes  reserved (0)
  0x08  u32 BE   total file size
  0x0c  u16 BE   entry count N
  0x20  N*16     entry records
Entry record (16 bytes):
  0x00  u32 BE   absolute file offset of the graphic block
  0x04  u16 BE   id
  0x06  10 bytes reserved
Graphic block (at record offset):
  0x00  u16 BE   width           (64)
  0x02  u16 BE   height          (64)
  0x04  u16 BE   frame count
  0x06  u16 BE   id
  0x08  8 bytes  reserved
  0x10  w*h*frames bytes         8-bit palette indices
```

Pixels are 8-bit indices into a 256-colour palette (768-byte RGB, e.g. the `XPAL`
palettes in `INTRFACE.FF`). Index 1 (magenta `ff 00 ff`) is the transparency key.
The exact world palette per tileset is still TBD; UI `XPAL0000` renders them plausibly.

```sh
python tools/grafix_extract.py WORLDS/GRAFIX00.DAT -p tools/out_intrface/raw/XPAL0000.DAT
```

## Other top-level data — TODO

| File | Notes |
|---|---|
| `BIGFILE.DAT` (64 MB) | starts `Copyright 1995, Reality Bytes, Inc.` then embedded `RIFF` data — bulk audio/stream pool |
| `STRDATA.DAT` | length-prefixed UI string table (`Out of memory.`, `Not enough disk space.`, …) |
| `HAVOC.ICO` | 32×32 4-bit icon |