FF7/WorldMap Module

Preamble

The following was originaly described by Tonberry, in qhimm's forum. It was completed by Ficedula sometimes later, who reversed texture data.

Two formats

BOT and MAP files are similar; BOT files are redundant and look like optimized versions of the corresponding MAP files.

Content

• WM0 is the above water map.
• WM2 is the underwater (submarine) map.
• WM3 is the snowstorm map.

MAP Format

File Structure

A worldmap file is divided in sections of 0xB800 bytes, each section representing a square block of the map.

Map Block

Each block consists in 16 meshes, organized in a grid-like fashion:

Map Block Grid arrangement

0	1	2	3
4	5	6	7
8	9	10	11
12	13	14	15

A block is recorded following the structure (all pointers are expressed in bytes relative to offset 0 of block):

For each m in 16 meshes:

size	description
4 bytes	Pointer to compressed data for mesh m

Followed by, for each m in 16 meshes:

size	description
variable	Compressed data for mesh m

The data for each mesh is independently compressed using LZSS, so the first 4 bytes are the size in bytes of the compressed data and the rest is the compressed data itself.

WM0.MAP

wm0.map contains 68 blocks. The first 63 of them are arranged in a grid-like fashion, made of 7 rows of 9 columns, like this:

wm0.map block arrangement

0	1	2	3	4	5	6	7	8
9	10	11	12	13	14	15	16	17
18	19	20	21	22	23	24	25	26
27	28	29	30	31	32	33	34	35
36	37	38	39	40	41	42	43	44
45	46	47	48	49	50	51	52	53
54	55	56	57	58	59	60	61	62

The last 5 meshes 63, 64, 65, 66, 67 and 68 replaces meshes 50, 41, 42, 60, 47 and 48 (respectively), according to the story of the game.

Mesh Structure

A worldmap mesh is recorded like this:

Header:

size	description
2 bytes	Number of triangles
2 bytes	Number of vertices

For each triangle t in number of triangles:

size	description
1 byte	Index of vertex 0 of triangle t
1 byte	Index of vertex 1 of triangle t
1 byte	Index of vertex 2 of triangle t
1 byte	Walkmap status of triangle t (see below)
1 byte	Coordinate u in texture for vertex 0
1 byte	Coordinate v in texture for vertex 0
1 byte	Coordinate u in texture for vertex 1
1 byte	Coordinate v in texture for vertex 1
1 byte	Coordinate u in texture for vertex 2
1 byte	Coordinate v in texture for vertex 2
2 bytes	Texture (see below)

For each vertex v in number of vertices:

size	description
2 bytes	Coordinate x of vertex v (signed)
2 bytes	Coordinate y of vertex v (signed)
2 bytes	Coordinate z of vertex v (signed)
2 bytes	(Unknown: Coordinate w of vertex v?)

For each vertex v in number of vertices:

size	description
2 bytes	Coordinate x of normal for vertex v
2 bytes	Coordinate y of normal for vertex v
2 bytes	Coordinate z of normal for vertex v
2 bytes	(Unknown: Coordinate w of normal for vertex v? "Always 0")

Walkmap

code	description
0x23	Deep sea (can't land highwind, water spray when flying low)
0x22	No sea spray from highwind, can't land
0x21	No sea spray from highwind, can't land
0x20	No sea spray, can land and walk

Observe that 0x21 and 0x22 describe the same status; it is thought that it may differentiate chocobos' behavior.

Texture

The lower 9 bits contain a texture number (0-511, but only 0-281 appear to be used). The text files in the Reeve download show how each number maps to one (or more) .TEX files within WORLD_US.LGP. The upper bits have something to do with texture coordinate mapping.

BOT format

(FIXME)