species-forms

An alternate form (an unown letter, and later an Alolan Vulpix or a Mega) is a full species here: its own Species id, its own entry in the species YAML under src/data/species/, its own sprite folder, its own dex tallies. What makes it a form is base-form: false and the id it was given.

The numbering

form id = 1000000 + dexNumber * 100 + formIndex

The default form is not in the band: its id is its dex number, which is what keeps Species === dexNumber true everywhere that relies on it. So Unown A is 201 and Unown B is 1020101.

The scheme buys three things: a hundred slots per species (Alcremie's 63 is the largest set the mainline prints), a species' forms sorting straight after it, and the base form recoverable from the id by arithmetic alone. The helpers in src/data/ids/forms.ts, beside the per-species form lists, are speciesDexNumber, speciesFormIndex and getBaseFormSpecies.

An id is stored player data, so nothing in the band may be renumbered once it ships. The same rule the family ids keep.

What reads the base form

• Region and sheets. getSpeciesRegion asks the dex number, so a form is filed beside its species: johto/1020101. The folder is still named after the id.
• The printed dex. getBaseForms backs the dex grid and dexOrder, and both list the default form alone: twenty-eight rows all numbered 201 and all called Unown is not a dex. The row lights up when any of its forms has been met.
• The dex record. pokedex_entries is keyed on the concrete species, so each form is seen and caught on its own. A read that counts pokemon rolls that up (countDexSpecies, readCaughtDexCount); a read that shows which forms were found does not.

The two dialogs

Pressing a dex row with several forms behind it opens SpeciesFormsDialog, not the entry: the row stands for the pokemon, and which form was meant has not been said yet. That dialog is only the grid of forms, labelled by formLabel rather than by the number they share, and pressing one hands over to DexEntryDialog for that form alone.

So a form's entry is an ordinary species page. It answers for itself, and its arrows walk the forms rather than the dex, since that is the list it was reached through. The default form has no page of its own beyond the one its first square opens.

A form's own ability

A shape worn in battle (an Origin forme with its orb, Sky Shaymin with a Gracidea) brings its own ability as a bonus. It is worn with unit.wearAbility whenever the unit takes the shape, by a form item, Terastallizing or an ability such as Tera Shift, and dropped when it leaves it, on top of whatever the catch carries. The list lives in SHAPE_ABILITIES in src/battle/items/forms.ts.

• It takes no ability slot, and Role Play, Skill Swap, Gastro Acid and Worry Seed cannot touch it, the way Shadow is exempt.
• It never trades away one of the catch's abilities mid-fight.
• It never goes in the base species' pool: a base species is not handed its form's ability.

Adding one

1. An id in Species, written directly after the species' own and inside the band.
2. baseForm: false on the registration, and the same dexNumber and family as the default form.
3. A name that tells it apart in a box. The default keeps the plain name; a variant is marked (Unown Q).
4. The species' dex number in FORMS in scripts/sprites/import.ts, with how many forms the game now has ids for. Anything past the count is skipped rather than imported under an id nothing knows.
5. pnpm import-sprites && pnpm compact-sprites.