DO/BTB

From Dark Omen Wiki

Contents 1 BUILDING BLOCKS 2 OVERALL FILE STRUCTURE 3 CHUNK DESCRIPTIONS 3.1 START/END CHUNK 3.2 HEADER CHUNK 3.3 UNKNOWN CHUNK 3.4 OBSTACLES CHUNK 3.5 REGION CHUNK 3.6 GAME OBJECTS CHUNK

BUILDING BLOCKS

The BTB file consists of chunks of the form:

struct CHUNK_HEADER
{
  unsigned int chunkType;
  unsigned int chunkSize; // excluding header
};

Each chunk consists of 'records' which are similar to chunks, but the record size is inclusive of the header.

struct RECORD_HEADER
{
  unsigned int recordType;
  unsigned int recordSize; // including header
};

OVERALL FILE STRUCTURE

The observed format of the BTB files in Dark Omen follows in order:

START/END CHUNK, type=0xBEAFEED0, size=0
   HEADER CHUNK, type=0, size=240
   UNKNOWN CHUNK, type=1, size=<varies>
   OBSTACLES CHUNK, type=2, size=<varies>
   
   REGION CHUNK 0, type=3, size=<varies>
   REGION CHUNK 1, type=3, size=<varies>
   .
   .
   .
   REGION CHUNK n, type=3, size=<varies>
   
   GAME OBJECT CHUNK, type=4, size=<varies>
START/END CHUNK, type=0xBEAFEEDO, size=0

CHUNK DESCRIPTIONS

START/END CHUNK

This chunk is just a marker of the start/end of the file; it contains no data

HEADER CHUNK

HEADER CHUNK, type=0, size=240
   INTEGER RECORD (Map width) type=1, size=12
   INTEGER RECORD (Map height) type=2, size=12
   STRING RECORD (Mercenary Army file name without extension) type=1001, size=40
   STRING RECORD (Enemy Army file name without extension) type=1002, size=40
   STRING RECORD (CTL filename without extension) type=1003, size=40
   STRING RECORD ("/0") type=1004, size=40
   STRING RECORD ("/0") type=1005, size=40
   2-TUPLE RECORD ( [Number of Regions in file, Number of line segments in all regions] ) type=9, size=16

UNKNOWN CHUNK

This chunk is made up of several 3-tuples, which contain unknown data

UNKNOWN CHUNK, type=2, size=<varies>
   3-TUPLE RECORD 0 (unknown) type=3, size=20
   3-TUPLE RECORD 1 (unknown) type=3, size=20 
   .
   .
   .
   3-TUPLE RECORD n (unknown) type=3, size=20

OBSTACLES CHUNK

This chunk seems to contain information about obstacles on the map (e.g. trees)

OBSTACLES CHUNK, type=3, size=<varies>
   INTEGER RECORD (unknown) type=8, size=12

   COMPOUND RECORD 0 (contains sub-records) type=501, size=80
      INTEGER RECORD (type of obstacle - might be bit flags - see table below) type=5, size=12
      INTEGER RECORD (x position) type=1, size=12
      INTEGER RECORD (y position) type=2, size=12
      INTEGER RECORD (unknown) type=4, size=12
      INTEGER RECORD (radius of area) type=6, size=12
      INTEGER RECORD (unknown - normally 0) type=7, size=12
   COMPOUND RECORD 1 (contains sub-records) type=501, size=80
   .
   .
   .
   COMPOUND RECORD n (contains sub-records) type=501, size=80

Type	Description
3	This seems to be a normal obstruction, such as a rock or a tree
5	Not sure what this is, might be tree trunks?

REGION CHUNK

This chunk contains information which delimits an area or path. It primarily consists of a list of line segments which define the path or polygon. These areas and paths seem to be used for a variety of reasons, some of which are listed below.

REGION CHUNK, type=4, size=<varies>
   STRING RECORD (the human-readable name of the region) type=1006, size=40
   INTEGER RECORD (type code - might be bit flags - see table below) type=5, size=12
   2-TUPLE RECORD ([starting X position, starting Y position]) type=10, size=16
   4-TUPLE RECORD 0 ([ line start X, line start Y, line end X, line end Y]) type=502, size=24
   4-TUPLE RECORD 1 ([ line start X, line start Y, line end X, line end Y]) type=502, size=24
   .
   .
   .
   4-TUPLE RECORD n ([ line start X, line start Y, line end X, line end Y]) type=502, size=24

GAME OBJECTS CHUNK

This chunk seems to hold a lot of the game-related info, for example initial enemy deployment, triggers for mission events, movement targets for the enemy AI.

GAME OBJECTS CHUNK, type=5, size=<varies>
   INTEGER RECORD (the number of game object compound records in this chunk) type=8, size=12

   COMPOUND RECORD 0 (contains sub-records and represents a game object) type=503, size=12
      INTEGER RECORD (type of game object - might be bit flags - see table below) type=5, size=12
      INTEGER RECORD (x position) type=1, size=12
      INTEGER RECORD (y position) type=2, size=12
      INTEGER RECORD (radius of area) type=6, size=12
      INTEGER RECORD (unknown) type=7, size=12
      INTEGER RECORD (unknown) type=11, size=12
      INTEGER RECORD (unknown for some types) type=12, size=12
      INTEGER RECORD (unknown) type=13, size=12
   COMPOUND RECORD 1 (contains sub-records and represents a game object) type=503, size=12
   .
   .
   .
   COMPOUND RECORD n (contains sub-records and represents a game object) type=503, size=12