1. Field jump — how the game moves between maps
    1. Jump request globals
    2. Triggers
      1. Field script opcodes
      2. Gateways (walked field exits)
      3. World map → field
    3. wm2field.tbl record format
    4. Field ID → filename: the maplist
    5. Where the field ID comes from
    6. End-to-end flow
    7. Address table

Field jump — how the game moves between maps

The complete path that takes the party from one field to another (or to the world map / a disc change): what triggers a jump, how the destination is described, how a field ID resolves to a filename, and how the party is placed on arrival. Addresses for FF8_EN.exe, image base 0x400000. The field runtime that consumes the loaded files is on Field rendering and collision.

Jump request globals

Every jump, whatever triggered it, fills the same handful of globals and lets the module handler act on them:

Global Address Meaning
globalFieldNextModuleID 0x1CE4760 Destination module: 1 = field, 6 = disc change (cdcheck), 7 = world map, 4 = intro/credits
MenuState_opcode_menu_id — Multi-purpose “next module parameter”; for a field jump = destination field ID
wm2field_FieldX / FieldY 0x1CE4764 / … Spawn X/Y on the destination field (0x7FFF = keep current position)
wm2field_FieldZ — Destination walkmesh triangle / Z
wm2field_FieldTarget — Facing direction on arrival

Triggers

Field script opcodes

Field scripts pop their arguments off the entity script stack and set the globals:

Opcode Function Behaviour
MAPJUMP 0x521A20 Jump to field ID with spawn X, Y, triangle (arg) and facing
MAPJUMP0 0x521C30 Jump keeping the party’s current position (X=Y=0x7FFF), target 0
MAPJUMP3 0x521AC0 Like MAPJUMP with an extra parameter word
WORLDMAPJUMP 0x521820 Sets globalFieldNextModuleID=7 → world map (toggles the savemap save-enable flag)
DISCJUMP 0x521B70 Sets globalFieldNextModuleID=6 → disc-change screen, disables the menu

Gateways (walked field exits)

Field_Collision_CheckGatewayCrossing (0x477980) tests the 12 gateway records in the .inf file (.inf+100, 32 bytes each). A gateway fires when the player is within touch radius of its line and the cross-product sign against the line flips between the previous and current position. On firing it sets the same globals from the record: destination field ID (< 0x48 routes to the world map = module 7, otherwise a field = module 1), spawn X/Y, triangle and facing. See the gateway record layout on the rendering/collision page.

World map → field

Boarding an entrance on the world map calls World_FindFieldEntrance, whose returned index selects a record in wm2field.tbl. The module handler (0x4708AC) reads that record to fill CURRENT_FIELD_ID + spawn globals, then enters the field.

wm2field.tbl record format

wm2field.tbl is an array of 24-byte records indexed by entrance ID:

Offset Size Field
+0 u16 spawn X
+2 u16 spawn Y
+4 u16 walkmesh triangle / Z
+6 u16 destination field ID
+8 u8 facing direction

(The table is loaded near the module handler; the same 24-byte stride is used by the world-map field-entrance path.)

Field ID → filename: the maplist

Field_LoadResources (0x471010) resolves the numeric field ID to a field name through mapdata\maplist — a plain newline-separated text file, one field name per line:

A field’s ID is simply its 0-based line number in maplist.

The loader (0x4710B1) reads maplist into a buffer and walks it: it skips control characters (< 16, i.e. CR/LF) between lines, counting lines until the count equals CURRENT_FIELD_ID, then copies that line’s printable characters (> 16) as CURRENT_FIELD_NAME. That name builds the field archive path and each section file is loaded:

.inf (gateways/triggers) · .ca (camera) · .id (walkmesh) · .map + .mim (background) · .msk (movie mask) · .rat / .mrt (encounter) · .msd (dialog) · .gsm / .sfx (sound) · .pmd (particles) · .jsm (scripts) · .pcb (extra).

Where the field ID comes from

CURRENT_FIELD_ID is set from different sources depending on the trigger:

  • World → field: the wm2field.tbl record’s field-ID word (module handler 0x4708CC).
  • Field → field / disc jump: MenuState_opcode_menu_id, which the jump opcode set (copied to CURRENT_FIELD_ID on field re-entry; the disc path copies it at 0x470EC0 after the disc check).
  • A few hardcoded returns exist (e.g. field 0x4B on a specific game-over return).

End-to-end flow 

flowchart TD
    A[Trigger: MAPJUMP opcode / gateway crossing / world-map entrance] --> B[Set globalFieldNextModuleID + field ID + spawn X/Y/triangle/facing]
    B --> C[FFModuleHandler_main_loop reads globalFieldNextModuleID]
    C -->|1 field| D[CURRENT_FIELD_ID set<br>from wm2field.tbl or MenuState_opcode_menu_id]
    C -->|7 world map| W[worldmap_init]
    C -->|6 disc| X[cdcheck screen]
    D --> E[Field_LoadResources: maplist line = field ID -> field name]
    E --> F[Load NAME.fs sections .inf/.ca/.id/.map/.mim/...]
    F --> G[Field_Walkmesh_PlaceEntitiesOnLoad:<br>spawn party at wm2field_FieldX/Y/triangle/facing<br>0x7FFF X/Y = keep position]
    G --> H[Field running]

Address table

Name Address
Field_Collision_CheckGatewayCrossing 0x477980
SCRIPT_MAPJUMP / MAPJUMP0 / MAPJUMP3 0x521A20 / 0x521C30 / 0x521AC0
SCRIPT_WORLDMAPJUMP / DISCJUMP 0x521820 / 0x521B70
FFModuleHandler_main_loop (module switch) 0x4706B0
Field_LoadResources (maplist + archive load) 0x471010
Field_Walkmesh_PlaceEntitiesOnLoad (spawn) 0x477C90
jumpFromWorldmapToField 0x52C579
globalFieldNextModuleID 0x1CE4760
CURRENT_FIELD_ID / CURRENT_FIELD_NAME 0x1CD2FC0 / 0x1CD2DB0

Addresses are for FF8_EN.exe (2000 PC release) as mapped in IDA (image base 0x400000).