The Art

Relevant files:

art.mul artidx.mul



• In the art files the graphics for land and static tiles are found.
  


• artidx.mul holds the index offsets for art.mul.
  To read an art sprite, first look into the artidx.mul file for it's offset, and then get it from art.mul. artidx.mul also contains the size of the data sprites, allowing to read the whole relevant chunk to speed IO.
  


• art.mul contains the art graphics.
  

Art types

There exist three different kinds of art data:


• Map Tiles: The map tiles have an id of 0 ... 0x4000 (0 ... 16384).
  They are used to display the unstretched map data. (Textures are used for the stretched ones) (Well at least should be..., Arachnide currently also stretches the map art...)



• Static Tiles: The static tiles have an id of 0x4000 ... 0x8000 (16384 ... 32768).
  These are all the static tiles, the world is constructed of.
  The static tiles are saved in a different format than the map tiles, although they are in the same file! (see blow)
  NOTE: To read a static tile graphic you have to add 0x4000 to it's id. This fact is bushed under the carpet at the InsideUO documentation. Dozens of programmers had to refind it out this several times...
  
  
• Character test: Character tests have id's of >= 0x8000 (>= 32768).
  They are stored in the same data format as the static tiles.
  Their use and sense are completely unknown... so as usual: know >> tell

InsideUO used to call the tiles 'raw' and 'run'. For me it's rather confusing, so in the Arachnide source and this documentation they are continuously called 'map' and 'static' instead.

artidx.mul

This file contains the indexes and to art.mul.
It's structured into groups of 12 bytes.
To load an art sprite with a specific ID, search for ID * 12 in this file, to get the correct index.

Index Record (12 bytes):



0	1	2	3	4	5	6	7	8	9	A	B
index				size				unknown

Map tiles (art.mul)

All map tiles have a size of 44x44 with a diagonal square of data.

First is a 4 byte (UNSIGNED INT32) header. Alazane has made some assumptions that it determines if it's a run or raw flag. However exact meaning has still to verified.
Are there maybe possibly map tile formated entries in the static data?

I've fired up good old paintbrush to get this a little visualized. The numeration here has an offset of 0 (as it is the natural index of most programs), so the maximum value is 43.


As all map tiles have identical size and format (mask), there is no need to store this information. The foreground data is simply stored as an continuous string out of 1012 pixels. (2024 bytes)

Static tiles (art.mul)

Header:

UNSIGNED INT32	Same (unknown) header again as for map tiles
UNSIGNED INT16	Width
UNSIGNED INT16	Height
UNSIGNED INT16 [Height]	Table of offset's for each row (the read-offset in this file).


The data for each row starts at the end of the Header plus the offset from the table.
A row is constructed out of one or several 'runs'.

Run:

UNSIGNED INT16	x-offset
UNSIGNED INT16	run (how many pixels to read)
UNSIGNED INT16 [run] ...	pixels


InsideUO defines all statics with an width or height >= 1024 as invalid, don't know if this is correct.
If xoffset + run are equal to zero this is the last run for this row, continue with next row.
(Start searching the new file position from the offset table).

Converse to the animation data, x-offset is here not (always) the offset to 0, but the offset to the end of the last run for this row!

- finished.

(A side note: I've on purpose not written in pseudo-code, as I think if some is interested in this, he can directly look into the Arachnide source. (it's written clearly enough :o) (and beside InsideUO is also there...)