FF7/Coordinates encoding

Coordinates on the world map are stored on 2 DWords and some basic decoding has to be done before you can manipulate them.

First DWord :

[1F 1E 1D 1C 1B 1A 19 18:17 16 15 14 13 12 11 10:0F 0E 0D 0C 0B 0A 09 08:07 06 05 04 03 02 01 00]
|     DIRECTION/0x10    |  OBJECT'S ID |               X COORDINATE OF THE OBJECT               |

Second DWord :

[1F 1E 1D 1C 1B 1A 19 18:17 16 15 14 13 12 11 10:0F 0E 0D 0C 0B 0A 09 08:07 06 05 04 03 02 01 00]
|        Z COORDINATE OF THE OBJECT       |              Y COORDINATE OF THE OBJECT             |

Notes :

• X is an unsigned value ranging from 0 to 0x47FFF
• Y is an unsigned value ranging from 0 to 0x37FFF
• Z is signed
• Direction is multiplied by 0x10 after reading from save-game, but that's not affecting anything so we can think of it as a byte value.

Table: Object ID

Value	Object
0x00	Party
0x03	Highwind
0x05	Tiny Bronco
0x06	Buggy
0x0D	Submarine
0x13	Chocobo
0x1D	Weapon

How to decode coordinates in C

Assuming 1st and 2nd are respectively the first and second DWords :

X = 1st & 0x7FFFF
Y = 2nd & 0x3FFFF
Z = 2nd >> 0x12     // shift arithmetic right
ID = (1st >> 0x13) & 0x1F
DIR = (1st >> 0x14) & 0x0FF0