FF7/WorldMap Module

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Revision as of 22:44, 30 December 2006 by my_wiki>Cyberman (Map Block)
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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 mesh 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)