LFD Format Overview

The LFD format is the standard multi-purpose data storage file type used by
LucasArts Entertainment LLC. Storage types vary from text to animations, and
all files end in the .LFD extension.

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LFD Structure

The following values are used through this and all of my file definitions
unless otherwise specified:
NAME	LENGTH	DESC
----	------	----
CHAR	1	ASCII character
INT	4	signed Int32

The LFD file has two main sections; the file header, and data block (which may 
include a sub-header).  Header blocks are 16-bytes with the following 
structure:

CHAR[4]	Type;
CHAR[8]	Name;
INT	Length;

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-- Type --

Multiple resource types exist that can be used in a given LFD file, and the use
of certain kinds allow for multiple types and multiple data blocks to be
contained in a single file.  Known resource types follow:

Type	Type (hex)	Data block contents
----	-----------	-----------------------------------------------------
ANIM	41 4E 49 4D	2D Animations
BLAS	42 4C 41 53	Creative .VOC sound data (mostly weapons)
BMAP	42 4D 41 50	Bitmap data?
CUST	43 55 53 54	??? Image data?
DELT	44 45 4C 54	Image data
FILM	46 49 4C 4D	View layout
FONT	46 4F 4E 54	Font glyph definition
GMID	47 4D 49 44	MIDI data
MASK	4D 41 53 4B	Cockpit transparency mask
MTRX	4D 54 52 58	???
PANL	50 41 4E 4C	Cockpit panel image data
PLTT	50 4C 54 54	Palette data
RMAP	52 4D 41 50	Subheader information for additional data blocks,
					will only appear as first header
SHIP	53 48 49 50	Craft External View vector data?
TEXT	54 45 58 54	Plain text data
VOIC	56 4F 49 43	Creative .VOC sound data (mostly sound fx/voice)
XACT	58 41 43 54	Backdrops, explosion graphics, etc

The RMAP type is always accompanied by a TITLE of "resource", and the LENGTH
will always be a multiple of 0x10, due to the data block containing only
additional headers.  When editing data within a RMAP-using LFD, care must be
taken to ensure that the LENGTHs defined in a given sub-header defined in the
RMAP matches the LENGTH for the corresponding data block.

The TEXT type can contain an unlimited number of seperate strings, but the
numbers of strings within a given TEXT section must remain constant to prevent
application failure.  If strings are being removed, the zero bytes on either
side must be kept.  A safe practice is to replace a string with 0x20 if you
truly wish for it to be removed.  LENGTH must be adjusted as well, unless care
is taken to adjust multiple strings such that the overall length does not
change. All TEXT data blocks begin with a WORD value I'll define as
TEXT_STRINGS. This is the number of STRINGs contained in the data block that
have STRING_LENGTH values, not the sub-strings within them.

Other TYPEs will be dealt with on an individual basis or within specific
LFD variants.

-- Name --

This value seems to have little bearing on function, other than to make a hex
dump slightly more readable.  Abbreviated descriptions are the norm.  Note that
certain resource types (FILM, for example) use the TITLE to define properties
in the layout.

-- Length --

This is the length of the data block in bytes that immediate follows the
header.  This value is little-endian, such that 0x0001224D is stored as
4D 22 01 00.

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