Difference between revisions of "SCUMM/Technical Reference/Index File"

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[[Category: SCUMM Technical Reference]]

Revision as of 09:49, 13 April 2007

SCUMM Technical ReferenceSCUMM index file


Introduction

Most of the information below are retrieved from the LucasHacks! site and from the Pascal source code of the IndexFileReader 1.2 (written by Ben Gorman (Bgbennyboy, http://quick.mixnmojo.com). In addition, ScummRevisited (written by Jimmi Thøgersen (Serge), http://www.mixnmojo.com/scumm/scummrev) turned out to be very useful in verifying the found offsets.

The SCUMM index file contains special information to allow quick random access to the resources in the other game files. It also includes the room names and some max limits for the game. The following filenames are used:


filenameSCUMM version
00.lfl / 000.lflV3/4
.000V5/6
.LA0V7/8


Version 1 to 3 use hardcoded offsets and cannot be treated that easily. For the other games, the index file can be used to determine the SCUMM version because there have been slight changes in each version.

  • Version 4: the 5th and 6th byte match RN or OR
  • Version 5: RNAM xor'ed with 0x69 at the beginning of the file, next 4 byte integer xor'ed with 0x69 is > 9
  • Version 6: RNAM xor'ed with 0x69 at the beginning, next 4 byte integer xor'ed with 0x69 is 9 (actually it's the size of the chunk. In V6 games, no room names are stored so the size is 4 bytes (header) + 4 bytes (size) + 1 byte for the termination character).
  • Version 7: RNAM at the beginning of the file (not xor'ed this time), next 4 bytes result in BE integer 9. (NOTE: must be verified!)
  • Version 8: RNAM at the beginning of the file, next 4 bytes integer is > 9


Conventions

As usual, the endianness (Wikipedia) is important. Unless stated, little endianess (LE) is used. BE is used as abbreviation for big endianness.

A Chunk is a named part of the file, e.g. RNAM. Each chunk has a header that contains at least the chunk name and its size. The following chunks are available:


RNAM Room Names In V5+
MAXS Maximum Values In V5+
DROO Directory of Rooms In V5+
DRSC Direcory of Room Scripts In V8
DSCR Directory of Scripts In V5+
DSOU Directory of Sounds In V5+
DCOS Directory of Costumes In V5+
DCHR Directory of Charsets In V5+
DOBJ Directory of Objects In V5+
AARY List of Arrays In V6+
ANAM Animation Names? In V7
RM Room Names In V3/4
0R Directory Of Rooms In V3/4
0S Directory Of Scripts? In V3/4
0N Directory Of Sounds? In V3/4
0C Directory Of Costumes? In V3/4
0O Directory Of Objects? In V3/4


Scumm 3/4

  • File's aren't xor'ed
  • Block Size does not include the 4 block size bytes, it's the size of the data that follows.


RN

Block Size         (4 bytes)
Block Name         (2 bytes)
  #Room No         (1 byte)
  #Room Name       (9 bytes) XOR'ed with FF
Blank (00) byte    (1 byte) Marks end of chunk


0R

Block Size         (4 bytes)
Block Name         (2 bytes)
No of items        (2 bytes)
  *Room Number     (1 byte)
  *Offset          (4 bytes)

0S

Block Size         (4 bytes)
Block Name         (2 bytes)
No of items        (2 bytes)
  *Room Number     (1 byte)
  *Offset          (4 bytes)

0N

Block Size         (4 bytes)
Block Name         (2 bytes)
No of items        (2 bytes)
  *Room Number     (1 byte)
  *Offset          (4 bytes)

0C

Block Size         (4 bytes)
Block Name         (2 bytes)
No of items        (2 bytes)
  *Room Number     (1 byte)
  *Offset          (4 bytes)

0O

Block Size         (4 bytes)
Block Name         (2 bytes)
No of items        (2 bytes)
  *Owner of Object (1 byte)


Scumm 5

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Scumm 6

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Scumm 7

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Scumm 8

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