Overworld Encounter Scripting Tools
What It Does
Three tools that make overworld wild Pokémon encounters usable in scripts and cutscenes, not just as ambient spawns. The tools were built in two commits, then improved by LordRainDance.
How It’s Implemented
GetOverworldMonSpecies reads the graphicsId of the last selected object event and returns a species ID. It covers every Pokémon object event in vanilla Emerald, and handles the expansion’s OBJ_EVENT_GFX_SPECIES() macro automatically as well. Shininess is also checked. The species and shiny status are written into VAR_0x8004 and VAR_0x8005 respectively.
startoverworldencounter is a macro that chains this function and others to start a battle. It calls GetOverworldMonSpecies, plays the returned species cry, creates the enemy party and triggers the wild battle. Originally the macro required a level argument, meaning every encounter in script needed its own level written in manually.
setobjectaswildencounter calls the script command ScrCmd_SetObjectAsWildEncounter that reads a localId and encounterType. This object must be a variable object event. It calculates spawn odds from SPAWN_ODDS/65536, and either hides the object via flag or pulls from the map’s actual wild encounter table to pick a species. Supported encounter types are ENCOUNTER_FIXED, ENCOUNTER_LAND, ENCOUNTER_SURF, ENCOUNTER_ROCK_SMASH, ENCOUNTER_OLD_ROD, ENCOUNTER_GOOD_ROD, and ENCOUNTER_SUPER_ROD. There is also a fallback table, in case the encounter header could not be used or if ENCOUNTER_FIXED is used. The species is packed into the object’s graphics ID variable, which is how the overworld encounter system reads it back.
The Contributor Improvement
A PR from lordraindance2 refactored startoverworldencounter so levels are drawn automatically from the route’s encounter table data rather than requiring a manual argument. The getter functions (GetLocalLandMon, GetLocalWaterMon, GetLocalRockSmashMon, GetLocalFishingMon) were changed from returning just a species ID to returning a full WildPokemon struct with level included. A new GenerateOverworldWildMon() function was added to get encounter data by graphics ID.
Wander Movement Types
Two additional movement types restrict where object events can wander, making them behave more naturally as overworld wild Pokémon. MOVEMENT_TYPE_WANDER_IN_GRASS prevents an object from stepping onto any non-grass metatile, and MOVEMENT_TYPE_WANDER_IN_WATER does the same for surfable water. Both use the existing wander step functions from MovementType_WanderAround, with only the direction-selection step (Step4) overridden to check metatile behaviour before committing to a move. If no valid tile exists in any direction, the object falls back to looking around in place rather than walking into an invalid tile.
The movement types are registered in sMovementTypeCallbacks, sMovementTypeHasRange, and gInitialMovementTypeFacingDirections in src/event_object_movement.c, and their step tables live in src/data/object_events/movement_type_func_tables.h. Note that MovementType_Wander_Step3 was consolidated in pokeemerald-expansion v1.9.2 — projects on earlier versions should use MovementType_WanderAround_Step3 instead.
Installation
This feature can be pulled by commits. The README.md of this branch can be used to add these changes. A full tutorial for the new movement types can be found on the Team Aqua’s Asset Repo wiki.
Why It’s In Ikigai
Pokémon Ikigai has scripted moments built around specific wild Pokémon, and these may contain encounters that can be shown better than just having the player step into grass. These tools make that possible without hardcoding species into battle setup scripts or writing specific workarounds for every encounter.