Question about MBM texture files (technical)

[Krupski]

Hi all,

I've written a small utility called "mbm2png" that converts MBM texture files to PNG. I wish to write the reverse utility also.

I've got one small question that I need to figure out first...

In the MBM file header are five 32 bit little-endian dwords that describe, in order:

Offset 0x00: 3KSP (i.e. a "magic number")

Offset 0x04: Bitmap WIDTH (i.e. 0x00020000 == 512 pixels wide)

Offset 0x08: Bitmap HEIGHT (i.e. 0x00020000 == 512 pixels tall)

Offset 0x0C: UNKNOWN (0x00000000 or 0x01000000 == 0 or 1)

Offset 0x10: Bit (color) depth (0x18000000 == 24 bits, 0x20000000 == 32 bits)

Offset 0x14: Texture data begins

Here's an example from a typical file:

-------------------------------------------------------------------------

00000000 03 4B 53 50 00 02 00 00 00 02 00 00 00 00 00 00 .KSP............

00000010 18 00 00 00 75 75 75 75 75 75 75 75 75 75 75 75 ....uuuuuuuuuuuu

00000020 75 75 75 75 75 75 75 75 75 75 75 75 75 75 75 75 uuuuuuuuuuuuuuuu

00000030 75 75 75 75 75 75 75 75 75 75 75 75 75 75 75 75 uuuuuuuuuuuuuuuu

00000040 75 75 75 75 75 75 75 75 75 75 75 75 75 75 75 75 uuuuuuuuuuuuuuuu

-------------------------------------------------------------------------

The one shown as "unknown" is the one I need to know about.

It's USUALLY a zero for 24 bit textures and a one for 32 bit textures (making me think it flags "transparency" or something)... but once in a while there is a 32 bit color depth file that has this word set to "zero".

It doesn't seem to matter when converting an MBM file to PNG, but I am assuming it's important the other way around (else it wouldn't be there - right?).

So, if anyone can tell me what this flag means so I can set it correctly in my "PNG2MBM" program, I will greatly appreciate it.

Thanks!

-- Roger