ordoor/doc/formats/mnu.md

*.mnu

These files appear to be the UI definitions for Chaos Gate. Some relate to system menus, other to in-game menus. Their names are hardcoded into the WH40K.exe binary. Each has a .obj file associated with it.

It's an ASCII-formatted text file with a 12-line header, followed by a number of descriptor records.

Here's the top of MainGame.mnu:

MainGame.obj
BACKGROUND COLOR 0..255..-1 trans : 0
HYPERTEXT COLOR 0..255            : 120
FONT TYPE 0..5                    : 10
wh40k_12
basfnt12
wh40k_47
wh40k_12_red
wh40k_12_blue
wh40k_12_green
wh40k_12_yellow
NULL

The first line of the header is a .obj file containing sprites we want to display on-screen. We see entries further down have a SPRITEID, which must reference entries in that file.

In SaveGame.mnu, we can see multiple .obj files can be referenced.

There are then 3 lines that seem to be fixed descriptor names with values that vary. Is this font colour, perhaps? Unsure.

Next is a variable-length list of font names, referencing files in the Fonts directory.

Finally, there's a list of records that specify the menu itself. Truncated contents of SaveGame.mnu:

#rem..........Background
MENUID     : 1
MENUTYPE   : 0
MOVEABLE   : 0
ACTIVE     : 1
SPRITEID   : 0
ACCELERATOR: 0
DRAW TYPE  : 0
SHARE      : -1
X-CORD     : -1
Y-CORD     : -1
DESC       :
*
#rem..........MAIN BACKGROUND
MENUID     : 2
MENUTYPE   : 45
MOVEABLE   : 0
ACTIVE     : 1
SPRITEID   : 0
ACCELERATOR: 0
DRAW TYPE  : 0
SHARE      : -1
X-CORD     : -1
Y-CORD     : -1
DESC       :
#rem.......... MAIN BACKGROUND
        SUBMENUID  : 1
        SUBMENUTYPE: 31
        FONTTYPE   : 20
        ACTIVE     : 0
        SPRITEID   : -1
        ACCELERATOR: 0
        DRAW TYPE  : 0
        SHARE      : 0
        SOUNDTYPE  : 0
        DESC       :
*
#rem..........Chat List Box Menu
MENUID     : 21
MENUTYPE   : 1
MOVEABLE   : 0
ACTIVE     : 1
SPRITEID   : 764
ACCELERATOR: 0
DRAW TYPE  : 0
SHARE      : -1
X-CORD     : -1
Y-CORD     : -1
DESC       :
[...]
*
~

We start processing these as soon as we see MENUID, I suppose. Each toplevel item is *-delimited, and the list is terminated with ~.

Each menu has a list of parameters:

Name	Examples	Purpose
MENUID	1, 2, 3	Maybe linking between menus?
MENUTYPE	0, 1, 2, 3, 45, 300	?
MOVEABLE	0	Unimplemented functionality?
ACTIVE	0, 1, 1,0	?
SPRITEID	-1, 0, 123, 16,-1,1	Select from .obj file?
ACCELERATOR		?
DRAW TYPE		?
SHARE		?
X-CORD	-1, 0, 200	X coordinate to draw at
Y-CORD	-1, 0, 200	Y coordinate to draw at
FONTTYPE		Choose a font from the above?
SOUNDTYPE		?
DESC	CHARACTER SELECT, 51005	Text, or reference to Data/USEng.dta

Submenus also show a couple of unique values:

Name	Examples	Purpose
SUBMENUID	1, 2, 3	As MENUID
SUBMENUTYPE	0, 1, 2	As MENUTYPE

It seems .mnu files can also include other files, which have the extension .mni (presumably for "Menu include"). Examples:

*
$GenDialog.mni
$GenLoad.mni

It looks like we just interpolate the named file into the text when we come across one of these lines.

(Sub)menu types

The types seem to refer to different types of UI widget. Here's a list of unique values:

Value	Meaning
0	Background
1	Logical menu grouping?
2	?
3	Standard button?
30	Equipment?
31	"Character helmet" / "Slot"
40	"X Line Y"
41	"X Line Y"
45	?
45,10,11,9	?
45,11,12,10	?
45,14,15,13	?
45,17,18,16	?
45,3,4,2	?
45,5,6,4	?
45,6,7,5	?
45,7,8,6	?
45,8,9,7	?
45,9,10,8	?
50	?
60	Other text to display? (UltEquip.mnu)
61	Text to display
70	Hypertext to display
91	?
100	?
110	?
120	?
200	Drop-down button?
205	Single list box item?
220	Psyker power?
221	Page?
228	Big buttons in Main.mnu
232	?
233	?
300	Pop-up dialog box
400,0,0,{8, 16}	?
400,22,22,{2, 4, 5, 6, 7, 8, 9, 9, 10, 13, 16}	?
400,30,-1,5	?
405,0,0,{8, 16}	?
405,22,22,{2, 4, 5, 6, 7, 8, 9, 10, 13, 16}	?
405,30,-1,5	?

Positioning

The X-CORD and Y-CORD values would seem to be related, to this, but they are universally set to 0 or -1.

Far more important are the XOffset and YOffset values for each sprite in the associated .obj files. Taking these into account is enough to draw Options.mnu successfully, for instance:

Animation

This seems to be done by choosing a different sprite to draw every N ticks. They are laid out sequentially, but I don't yet know how to animate them. It's likely to be the same approach as used for other obj files.

Looking at Main.mnu, it points at the object fail Main.obj. This has 118 sprites, which can be described as follows:

Start	Count	Desc
0	1	Background image
1	3	New game button: base, pressed, disabled
4	3	Load game button: base, pressed, disabled
7	3	Multiplayer button: base, pressed, disabled
10	3	Settings button: base, pressed, disabled
13	3	Quit button: base, pressed, disabled
16	20	New game button: 20 animation frames
36	20	Load game button: 20 animation frames
56	20	Multiplayer button: 20 animation frames
76	20	Settings button: 20 animation frames
96	20	Quit button: 20 animation frames
116	1	Section of background ("Menu title")
117	1	Version hotspot

So we have 5 buttons with very similar characteristics, but at different sprite offsets, and two distinct ranges per button, plus some others. Here's some attributes plucked from Main.mnu:

Name	(SUB)MENUTYPE	"Active"	"SPRITEID"	"DRAW TYPE"	"SHARE"
Background	1	1	0	0	-1
Start menu	1	1	-1	0	-1
New game	228	1,0	16,-1,1	20	1
Load game	228	1,0	36,-1,4	20	4
MP game	228	1,0	56,-1,7	20	7
Options	228	1,0	76,-1,10	20	10
Quit	228	1,0	96,-1,13	20	13
Menu title	61	1	-1	0	116
V hotspot	61	1	-1	0	117

The buttons, menu title and version hotspot are submenus of the start menu.

MENUTYPE

This is the only menu where we see a type of 228. ~750 other unique values are observed, suggesting structure. For instance, we have 24, 240, 241 and 2410, but not 2411 or 2409. Sometimes we have a comma-separated list, e.g.: 400,30,-1,5.

A listing of some currently-known values:

Value	Type
0	Static image
1	Menu
3	Button
45	Thumb
50	Invoke? Button?
61	"Overlay"
70	"Hypertext"
91	Checkbox
220	Animation sample
228	Main menu button
232	Slider

Hypothesis: MENUTYPE and SUBMENUTYPE are actually distinct lists of values. So far, I've been treating them as the same thing, but, e.g., MainGame.mnu has a MENUTYPE: 45 which is labelled "MAIN BACKGROUND", while SUBMENUTYPE: 45 is tentatively labelled a "thumb" and used in text boxes. There are also a few cases where I've had to manually override the MENUTYPE because it coincides with Button.

ACTIVE

There are only 4 values seen across all menus: 0, 1, 1,0, 102 and 1,1. Perhaps this represents possible states?

Sprite selection

For the background (MENUTYPE: 1), this points simply at the sprite index in the object file. For the start menu, it's -1 (no sprite, I assume). For the menu title and version hotspot (MENUTYPE: 61, it's -1 too.

For the buttons, it's a list pointing to the start of the 20 animated frames, -1, then the start of the 3 static frames.

DRAW TYPE is the number of animated frames. We only use the animated frames when the button is focused. SHARE repeats the start of the static frames, and is the only place they're found for the menu title and version hotspot.