Skip to content

Pokemon index extension branch

Jump to bottom
aaaaaa123456789 edited this page Mar 28, 2020 · 18 revisions

Pokémon index extension branch (expand-mon-ID)

This is the first feature branch of the repository, implementing an actual case of 16-bit extension. Pokémon species IDs are extended to 16 bits, updating the various subsystems that depend on the actual indexes to use the conversion table created by this branch.

(NOTE: this documentation page is a work in progress. Items below that don't link anywhere haven't been written yet.)

Conversion table definition

An unused, suitably-aligned region of WRAM bank 2, starting at address $D200, was reserved for the Pokémon index conversion table, as well as any further conversion tables added by future branches.

The table itself is declared as wPokemonIndexTable, with a corresponding set of parameter constants prefixed by MON_TABLE; the values of those parameters are the following:

Constant Value
MON_TABLE_ENTRIES 100
MON_TABLE_LOCKED_ENTRIES 30
MON_TABLE_CACHE_SIZE 16
MON_TABLE_SAVED_RECENT_INDEXES 8
MON_TABLE_MINIMUM_RESERVED_INDEX $FD

The parameters defined above make the table fit exactly in $100 bytes with no padding. The minimum reserved ID is set to $FD so eggs can continue using that value: the EGG constant is redefined as -3, which will expand as $FD when used as an 8-bit value and $FFFD when used as a 16-bit value; since $FD is defined as a reserved ID, it will convert to $FFFD (and vice-versa), making the EGG constant valid both as an 8-bit ID and a 16-bit index.

The home bank functions needed to access this table are declared as GetPokemonIndexFromID, GetPokemonIDFromIndex, LockPokemonID and GetLockedPokemonID. The garbage collector function is also exposed as PokemonTableGarbageCollection.

The garbage collector will look for valid IDs in the following locations to consider them as "in use":

  • Party and currently-selected PC box
  • Opponent trainer's party and linked player's party
  • Roaming Pokémon
  • Pokémon left in the Day-Care
  • Bug-Catching Contest current Pokémon and results
  • Various temporary buffers (wBattleMon, wEnemyMon, wTempMon, wBufferMon, odd egg data, base stat data)

Affected subsystems

The following subsystems in the game were updated to use 16-bit indexes correctly:

  • Base data: adapted the helper function GetBaseData to do an ID-to-index conversion and fixed other references to that data, and removed the species ID from the base data (it is now computed through an index-to-ID conversion).
  • Battle functions:
    • BattleCommand_Critical, DittoMetalPowder, LightBallBoost and ThickClubBoost use 16-bit indexes for their checks.
    • LoadEnemyMon checks for Unown's and Magikarp's 16-bit indexes now.
  • Battle Tower trainer data and party validation
  • Breeding: adapted to use 16-bit indexes all throughout, including when checking for a Ditto, a Togepi or a Nidoran.
  • Bug-Catching Contest: all tables and functions were updated to load and use 16-bit indexes.
  • Evolutions, learnsets and egg moves
  • In-game trades: redesigned the data to contain a 16-bit index for the wanted and given Pokémon, and adapted the corresponding functions.
  • Intro sequence: updated to use Wooper's 16-bit index.
  • Leftover mobile code: fixed for completeness.
  • Miscellaneous functions:
    • IsAPokemon will now check whether the ID is a valid table ID (or an egg).
    • MoonBallMultiplier will properly parse 16-bit species indexes in evolution data. (Also, it now works as expected, instead of looking for a non-existent evolutionary item.)
    • Unreferenced_CorrectPartyErrors will correctly handle table IDs and correct invalid ones.
  • Odd Egg generation: the species is now generated from a 16-bit species index table.
  • Overworld:
    • Berry Juice generation will properly check for Shuckle's 16-bit index.
    • Pokémon sprites were adapted the data and functions to index into a 16-bit table.
    • Surf icon now properly checks for Pikachu's 16-bit index.
  • Player room's decorations: adapted the data table to contain 16-bit species indexes for decorations based on Pokémon sprites (by adding a lookup table) and updated the corresponding functions to read from that table.
  • Pokémon cries, dex entries and footprints
  • Pokémon move screen: updated to check for a valid table ID (instead of an ID no greater than NUM_POKEMON) when checking for a previous or a next Pokémon in order to display scroll arrows.
  • Pokémon names, pics and palettes: adapted the loader functions to do an ID-to-index conversion.
  • Map scripts and events
  • Time Capsule: adapted to use 16-bit species indexes in checks, including specific checks for Magnemite and Magneton (whose types changed between generations 1 and 2).
  • Trainer data
  • Unown's special handling: checks for Unown when displaying or printing a Pokémon's picture, when catching a Pokémon, when evolving a Pokémon and when a Pokémon is sent out to battle adapted to check for Unown's 16-bit index.
  • Wild Pokémon: updated all wild Pokémon tables to contain 16-bit indexes and fixed the functions that load wild data to load those indexes correctly (including performing index-to-ID conversions).

Map scripting changes

TODO

Evolutions and learnsets

TODO

Trainer data

TODO

Battle Tower

TODO

Pokédex

TODO

Clone this wiki locally