FONT LFD Resource Type
Author: Jagged Fel (jaggedfel621@gmail.com)
Site: http://idmr.empirereborn.net
Updated: 2009.10.05
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The FONT Resource type contains the fonts seen in various locations of the
game. "font6" is used as map and FG tags within the briefing, "font8" is the
title text and caption text. "font12" and "font18" are seen in the pilot
selection screen.  These 4 are all found in EMPIRE.LFD, and are just examples,
they are used in multiple places and are not the only ones.

The information itself is a monochrome bitmap image, one for each glyph.

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FONT Structure

The following values are used through this and all of my file definitions
unless otherwise specified:
NAME	LENGTH	DESC
----	------	----
BYTE	1	unsigned 8-bit
CHAR	1	ASCII character
SHORT	2	signed Int16
INT	4	signed Int32

--
0x00	Header
0x10	SHORT	StartingChar (0x20)
0x12	SHORT	NumberOfGlyphs
0x14	SHORT	BitsPerScanline
0x16	SHORT	Height
0x18	SHORT	BaseLine
0x1A	SHORT	Reserved (0)
0x1C	BYTE[NumberOfGlyphs]	GlyphWidths
	Glyph[]
--

struct Header (size 0x10)
{
	0x0	CHAR[4]	"FONT"
	0x4	CHAR[8]	Name
	0xC	INT	Length
}

struct Glyph (size BitsPerScanline*Height/8)
{
	BYTE[Height,BitsPerScanline/8]	Rows
}

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FONT Detail

In TIE95 there are a total of seven FONT resources, all of which have a
StartingChar of 0x20, which makes sense since you kinda need a space, and
there's nothing really before that anyway. Only "TITLE.LFD/helv-20" has a
non-0x60 value for NumberOfGlyphs, which is the scrolling text in the title
crawl.

BitsPerScanline tells you how much you have to read before going on to the
next line. Always a multiple of 8. Height is just that, how many rows per
glyph. BaseLine is a zero-indexed row that is defined as the bottom of the
glyphs. This is so letters such as 'j' and 'g' hang below the line as they
should.

The GlyphWidth values are in pixels, starting from the left of the glyph.

-- Row --

The Row values within the actual glyph data are bit fields.  Monochrome
bitmaps, so '0' is transparent, '1' is solid.

E0 A0 E0 A0 A0 00	from "EMPIRE.LFD/font6" is the letter 'A'

XXX.....		E0 = b11100000
X.X.....		A0 = b10100000
XXX.....		b11100000
X.X.....		b10100000
X.X.....		b10100000
........		b00000000

If the BitsPer value is 0x10, then the rows are 16 pixels wide, 0x18 is 24 pix
wide, etc.  The Width value for the letter 'A' in this case is 03, which as can
be seen makes sense.  Spaces between letters are automatically counted as 1
pixel.
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