We have EVEN MORE themes now, but some old ones are gone...
Show Posts
1261
Final Fantasy IV Research & Development / Decoding World Map Triggers
« on: October 17, 2012, 11:10:37 AM »
I've been working on figuring out the Overworld/Underworld/Moon map triggers.
Most of what follows is interpreted from Yousei's document. Hopefully this will clarify a bit what took me some experimenting and time to figure out:
The World Map trigger data is located from D0066-D01FF (headered US ROM). Each trigger is five bytes long.
Byte 0: X-Position
Byte 1: Y-Position
Byte 2: Call to load a new map (or play an event - more on this later)
Byte 3: New map X-Pos
Byte 4: New Map Y-Pos
So, at D0066, we have:
65 9C 24 10 1E
"At 65/9C (NW Corner of Baron Castle), load map 24 (Baron Castle) at position 10/1E."
If Byte 2 = FF, this is an event call. The game, as programmed, has seven of these - two in the Overworld and five in the Underworld:
It's also worth mentioning that, as with location maps, if the position of a trigger is moved, the target location must contain a trigger-friendly tile in order for the trigger to function (such as a town tile, cave, castle, etc.). You can use Yousei's FF4ed to do this (if you change the data first, the editor will blue-in the new trigger location).
Also - I think D0060-D0065 contains the data related to which triggers belong in which World Map, but have not yet experimented with this.
Most of what follows is interpreted from Yousei's document. Hopefully this will clarify a bit what took me some experimenting and time to figure out:
The World Map trigger data is located from D0066-D01FF (headered US ROM). Each trigger is five bytes long.
Byte 0: X-Position
Byte 1: Y-Position
Byte 2: Call to load a new map (or play an event - more on this later)
Byte 3: New map X-Pos
Byte 4: New Map Y-Pos
So, at D0066, we have:
65 9C 24 10 1E
"At 65/9C (NW Corner of Baron Castle), load map 24 (Baron Castle) at position 10/1E."
If Byte 2 = FF, this is an event call. The game, as programmed, has seven of these - two in the Overworld and five in the Underworld:
Quote
Event Call ID X-Pos Y-Pos Event ID DescriptionI don't quite understand why the event call IDs do not match the actual event IDs. Also, I've played around with inserting other values besides the four used, and have not found any others that work (but have not exhausted all 252 possibilities by any stretch).
------------- ----- ----- -------- -----------
(Overworld)
10 77 3E 42 Redwings Bombing Damcyan
2B DD 38 83 Boarding the ship in Fabul
(Underworld)
58 30 0F 06 Entering the Tower of Bab-il from the Underworld
"" 31 0F "" ""
36 37 14 FE Dwarf tanks shooting tower of Bab-il
"" 36 11 "" ""
"" 33 10 "" ""
It's also worth mentioning that, as with location maps, if the position of a trigger is moved, the target location must contain a trigger-friendly tile in order for the trigger to function (such as a town tile, cave, castle, etc.). You can use Yousei's FF4ed to do this (if you change the data first, the editor will blue-in the new trigger location).
Also - I think D0060-D0065 contains the data related to which triggers belong in which World Map, but have not yet experimented with this.
