WindThunder AMP_File V1.0 Format
Archived from http://www.cinnamonpirate.com/docs/wtamp on 2006/2/7
Grudgingly copied and pasted from his browser by D

AMP files are WindThunder’s transparent PCX format used in Heroine Anthem I&II. Their extension is usually .AMP, .000 or .001.

Rather than specify a mask bit, a second, monochrome PCX file is stored after the full-color image.

In theory, this format will work with other image formats besides PCX, but I do not believe it is used in the games with any other format.

Every AMP file begins with a 30 byte header. Offsets are stored in little endian ordering, and strings are padded with 0×00:

ID Tag: 'AMP_FILE V1.0' [14 bytes, string]

Image width [4 bytes, long]

Image height [4 bytes, long]

File size [4 bytes, long]

Mask size [4 bytes, long]

(data)

Immediately following the header is the first graphic. The second graphic [mask] begins at (File size + 30) and continues until the end of the file.

Proof of method code is included below:

$filename = 'CatchPointFont.000';

$fd = fopen($filename, 'rb');

if(rtrim(fread($fd, 14)) != "AMP_FILE V1.0") die;

$imgwidth = unpack('V*', fread($fd, 4));

$imgheight = unpack('V*', fread($fd, 4));

$filesize = unpack('V*', fread($fd, 4));

$masksize = unpack('V*', fread($fd, 4));

$fo = fopen($filename.'.image', "w");

fputs($fo, fread($fd, $filesize));

fclose($fo);

$fo = fopen($filename.'.mask', "w");

fputs($fo, fread($fd, $masksize));

fclose($fo);

fclose($fd);