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. e.g: 00: South, 40: East, 80: North, C0: West

Table: Object ID

Value	Object
0x00	Cloud
0x01	Tifa
0x02	Cid
0x03	Highwind
0x04	Yellow Chocobo
0x05	Tiny Bronco
0x06	Buggy
0x07	Cannon from Junon
0x0C	Phoenix from Fort Condor
0x0D	Submarine
0x0E	Gold Saucer
0x0F	Rocket
0x10	Rocket launch pad
0x13	Chocobo
0x18	North crater dome
0x19	Ancient Forest
0x1D	Weapon

How to decode coordinates

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