Port field moves from the menu, SEL with Select, and moving Pokémon in Bill's PC

Field moves chosen in the party menu run their original checks and the
ROM's from-menu scripts (Cut, Surf, Strength, Flash, Whirlpool, Waterfall,
Sweet Scent), and Softboiled and Milk Drink share HP. SEL registers a key
item that Select then uses, replacing the Key Items shortcut, and Bill's
PC moves Pokémon between the party and every box.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/game/battle/constants.ts

@@ -256,6 +256,8 @@ export const C = {
   KEY_ITEM_POCKET: 2,
   TM_HM_POCKET: 3,
   PP_UP: 0x3e,
+  SOFTBOILED: 0x87,
+  MILK_DRINK: 0xd0,
   RARE_CANDY: 0x20,
   HP_UP: 0x1a,
   PROTEIN: 0x1b,

src/game/party/storage.ts

@@ -85,6 +85,15 @@ export function withdrawnMon(data: PokemonData, box: BoxMon): PartyMon {
   return { ...mon, level, status: 0, hp: stats[0], stats };
 }
 
+/** A boxed Pokémon in MOVE PKMN W/O MAIL's wBufferMon: its stored level,
+ * CalcBufferMonStats' stats with stat experience, full HP (none for an
+ * Egg) and no status. */
+export function bufferMon(data: PokemonData, box: BoxMon): PartyMon {
+  const mon = structuredClone(box);
+  const stats = calcStats(data, mon.species, mon.dvs, mon.level, mon.statExp);
+  return { ...mon, status: 0, hp: mon.species === 0xfd ? 0 : stats[0], stats };
+}
+
 /** ReceiveItem into wNumPCItems. */
 export function receivePCItem(
   items: ItemSlot[],

src/game/rom/assets.ts

@@ -124,6 +124,7 @@ export class CrystalAssets {
       tileset: r.byte(header + 1),
       environment: r.byte(header + 2),
       paletteMode: r.byte(header + 7) & 15,
+      attributes,
       blocks: r.slice(r.far(attributes + 3), blockWidth * blockHeight),
       warps: [],
       backgroundEvents: [],

src/game/rom/profile.ts

@@ -169,6 +169,7 @@ export const EVENTS = {
   playersHouseDoll1: 1858,
   playersHouseDoll2: 1859,
   playersHouseBigDoll: 1860,
+  wallOpenedInAerodactylChamber: 809,
 } as const;
 
 /** Engine flag indices named directly by translated routines. */
@@ -219,6 +220,26 @@ export const OVERWORLD = {
   IconPointers: 0x8ebbf,
   AskSurfScript: 0xca2c,
   "UsedSurfScript.stubbed_fn": 0xc9a2,
+  Script_CutFromMenu: 0xc7fe,
+  SurfFromMenuScript: 0xc983,
+  Script_StrengthFromMenu: 0xcd29,
+  Script_UseFlash: 0xc8e6,
+  UseFlashTextScript: 0xc8f3,
+  "UseFlashTextScript.BlankText": 0xc908,
+  BlindingFlash: 0x8c7e1,
+  Script_WhirlpoolFromMenu: 0xce0b,
+  Script_WaterfallFromMenu: 0xcb1c,
+  "SweetScentFromMenu.SweetScent": 0x506c8,
+  SweetScentEncounter: 0x506ef,
+  "CheckBadge.BadgeRequiredText": 0xc73d,
+  "FieldMoveFailed.CantUseItemText": 0xc780,
+  CutNothingText: 0xc7c9,
+  CantSurfText: 0xc9ae,
+  AlreadySurfingText: 0xc9b3,
+  "EscapeRopeOrDig.CantUseDigText": 0xcc26,
+  "TeleportFunction.CantUseTeleportText": 0xccb6,
+  "Softboiled_MilkDrinkFunction.ItemCantUseOnMonText": 0xf44a,
+  RuinsOfAlphAerodactylChamber_MapAttributes: 0x958e8,
   AskCutScript: 0xd1a9,
   "AskCutScript.CheckMap": 0xd1ba,
   CantCutScript: 0xd1cd,
@@ -237,7 +258,9 @@ export const OVERWORLD = {
   ChrisStateSprites: 0x141b7,
   KrisStateSprites: 0x141c0,
   Script_GetOnBike: 0xd13e,
+  Script_GetOnBike_Register: 0xd14e,
   Script_GetOffBike: 0xd158,
+  Script_GetOffBike_Register: 0xd16b,
   Script_CantGetOffBike: 0xd171,
   UpdatePlayerSprite: 0xe4a,
   PlayMapMusic: 0x3cdf,
@@ -387,6 +410,12 @@ export const PC = {
   PCString_BoxFull: 0xe3575,
   PCString_PartyFull: 0xe3586,
   PCString_NoReleasingEGGS: 0xe3597,
+  PCString_MoveToWhere: 0xe3500,
+  PCString_TheresNoRoom: 0xe3521,
+  "_MovePKMNWithoutMail.MenuData": 0xe28cb,
+  MoveMonWOMailSaveText: 0x152a6,
+  "BillsPC_MovePKMNMenu.PCMonHoldingMailText": 0xe4f9,
+  "MovePKMNWithoutMail_InsertMon.Saving_LeaveOn": 0xe3233,
   "BillsPC_PlaceChooseABoxString.ChooseABox": 0xe37a1,
   "BillsPC_PlaceEmptyBoxString_SFX.NoMonString": 0xe37d3,
   "BillsPC_PrintBoxName.Current": 0xe36f1,
@@ -415,6 +444,11 @@ export const MENU = {
   MonMenuOptions: 0x24cd9,
   "GiveTakeItemMenuData.Items": 0x12ca3,
   String_MoveWhere: 0x1316b,
+  "MonMenu_Softboiled_MilkDrink.PokemonNotEnoughHPText": 0x12f00,
+  MayRegisterItemText: 0x13340,
+  RegisteredItemText: 0x10afd,
+  CantRegisterText: 0x10b02,
+  ItemsOakWarningText: 0x12a67,
   MailItems: 0xb9e80,
   PokemonSwapItemText: 0x12caf,
   PokemonHoldItemText: 0x12cb4,

src/game/runtime.ts

@@ -9,7 +9,6 @@ import { WorldRenderer } from "./rendering/renderer";
 export class NativeRuntime implements GameRuntime {
   readonly id = "crystal-native-world-v1";
   world?: GameWorld;
-  fieldMenuOpen = false;
   private renderer?: WorldRenderer;
   private pressed = new Set<Button>();
   private raf = 0;
@@ -26,7 +25,6 @@ export class NativeRuntime implements GameRuntime {
   ) {}
   async load(bytes: Uint8Array, canvas: HTMLCanvasElement) {
     this.dispose();
-    this.fieldMenuOpen = false;
     const assets = new CrystalAssets(bytes);
     const world = new GameWorld(assets);
     this.world = world;
@@ -72,18 +70,17 @@ export class NativeRuntime implements GameRuntime {
     )
       world.moveCursor(button as Direction);
     if (button === "start") world.openStartMenu();
+    if (button === "select") world.useSelect();
     this.publish();
   }
   /** Start: the start menu, while the player stands still. */
   openStartMenu() {
-    this.fieldMenuOpen = false;
     this.world?.openStartMenu();
     this.publish();
   }
-  useBicycle() {
-    this.fieldMenuOpen = false;
-    if (this.world && !this.world.useBicycle())
-      this.world.notice = "You can’t use the BICYCLE here.";
+  /** Select: the registered item (SelectMenu). */
+  useSelect() {
+    this.world?.useSelect();
     this.publish();
   }
   /** Choose a pack entry from a pointer control. */
@@ -128,7 +125,7 @@ export class NativeRuntime implements GameRuntime {
       let ticks = 0;
       while (this.pending >= 1 / TICKS_PER_SECOND && ticks < 6) {
         this.pending -= 1 / TICKS_PER_SECOND;
-        if (!this.fieldMenuOpen) world.tick(held);
+        world.tick(held);
         ticks++;
       }
       if (ticks === 6) this.pending = 0;
@@ -247,7 +244,6 @@ export class NativeRuntime implements GameRuntime {
   restoreState(bytes: Uint8Array) {
     if (!this.world || bytes.length > 64_000)
       throw new Error("Invalid native save size.");
-    this.fieldMenuOpen = false;
     this.world.restore(
       JSON.parse(new TextDecoder("utf-8", { fatal: true }).decode(bytes)),
     );

src/game/scripts/interpreter.ts

@@ -102,6 +102,9 @@ export interface ScriptState {
    * (a dark cave lit) and STATUSFLAGS_NO_WILD_ENCOUNTERS_F (wildoff). */
   flash: boolean;
   noWildEncounters: boolean;
+  /** wWhichRegisteredItem (pocket in the top two bits, 1-based slot below)
+   * and wRegisteredItem: the item Select uses; zeros when none. */
+  registeredItem: { which: number; item: number };
 }
 export const emptyScriptState = (): ScriptState => ({
   decorations: emptyDecorations(),
@@ -126,6 +129,7 @@ export const emptyScriptState = (): ScriptState => ({
   backupWarp: null,
   flash: false,
   noWildEncounters: false,
+  registeredItem: { which: 0, item: 0 },
 });
 export const copyScriptState = (state: ScriptState): ScriptState => ({
   decorations: { ...state.decorations },
@@ -153,6 +157,7 @@ export const copyScriptState = (state: ScriptState): ScriptState => ({
   backupWarp: state.backupWarp && { ...state.backupWarp },
   flash: state.flash,
   noWildEncounters: state.noWildEncounters,
+  registeredItem: { ...state.registeredItem },
 });
 
 /** Object operands keep the script's numbering: 0 is the player, 2+ are map
@@ -472,6 +477,11 @@ export class ScriptRun {
       rival: this.state.rivalName,
       strings: { ...this.host.text().strings, ...this.strings },
       numbers: { ...this.host.text().numbers, ...this.numbers },
+      // UseFlashTextScript: SFX_FLASH, then an empty text.
+      asm: (offset) =>
+        offset === OVERWORLD.UseFlashTextScript + 4
+          ? OVERWORLD["UseFlashTextScript.BlankText"]
+          : undefined,
     };
   }
 
@@ -759,6 +769,13 @@ export class ScriptRun {
           ) {
             const tile = this.host.playerCollision();
             value = Number(!(tile === 0x33 || tile === 0x3b)); // CheckWaterfallTile
+          } else if (routine === OVERWORLD.BlindingFlash) {
+            // STATUSFLAGS_FLASH_F; the fades and palettes are presentation.
+            this.state.flash = true;
+          } else if (routine === OVERWORLD.SweetScentEncounter) {
+            // Chosen by the world when the move was used (CanEncounterWildMon,
+            // GetMapEncounterRate and ChooseWildEncounter).
+            value = Number(this.options.wild !== undefined);
           } else if (routine === OVERWORLD["UsedSurfScript.stubbed_fn"]) {
             // StubbedTrainerRankings_Surf: the cut Trainer Rankings feature.
           } else if (!Object.values(EMPTY_ROUTINES).includes(routine as never))

src/game/scripts/pc.ts

@@ -1,14 +1,23 @@
 import type { RomReader } from "../rom/reader";
 import type { PokemonData } from "../rom/pokemon";
-import { ENGINE_FLAGS, PC, RAM } from "../rom/profile";
+import { ENGINE_FLAGS, MENU, PC, RAM } from "../rom/profile";
 import { receiveItem, removeFromSlot, type ItemSlot } from "../party/bag";
-import { BOX_NAME_PATTERN, PARTY_LENGTH } from "../party/pokemon";
 import {
+  BOX_NAME_PATTERN,
+  PARTY_LENGTH,
+  type PartyMon,
+} from "../party/pokemon";
+import {
+  MONS_PER_BOX,
   NUM_BOXES,
+  bufferMon,
   currentBox,
   depositMon,
   receivePCItem,
+  restorePP,
+  toBoxMon,
   withdrawnMon,
+  type BoxMon,
 } from "../party/storage";
 import { readString, readText, type TextContext } from "./text";
 import type { MartEntry, ScriptEffect, ScriptState } from "./interpreter";
@@ -422,15 +431,128 @@ export class PcSession {
       if (choice === BILLSPC_WITHDRAW) yield* this.withdrawMons();
       else if (choice === BILLSPC_DEPOSIT) yield* this.depositMons();
       else if (choice === BILLSPC_CHANGE_BOX) yield* this.changeBox();
-      else if (choice === BILLSPC_MOVE)
-        yield {
-          kind: "notice",
-          text: "Moving Pokémon between boxes is not ported yet.",
-        };
+      else if (choice === BILLSPC_MOVE) yield* this.movePKMNMenu();
       else return;
     }
   }
 
+  // ------------------------------------------------ MOVE PKMN W/O MAIL
+
+  /** BillsPC_MovePKMNMenu: refused while a party Pokémon holds MAIL
+   * (IsAnyMonHoldingMail), then StartMoveMonWOMail_SaveGame's question. The
+   * native session saves by itself, so no save messages follow. */
+  private *movePKMNMenu(): Gen {
+    const r = this.host.reader;
+    const mail = new Set<number>();
+    for (let p = MENU.MailItems; r.byte(p) !== 0xff; p++) mail.add(r.byte(p));
+    if (this.state.party.some((mon) => mail.has(mon.item)))
+      return yield* this.print(PC["BillsPC_MovePKMNMenu.PCMonHoldingMailText"]);
+    const ok = yield { kind: "yesno", pages: this.pages(PC.MoveMonWOMailSaveText) };
+    if (ok) yield* this.moveWithoutMail();
+  }
+  /** wBillsPC_LoadedBox: 0 is the party, 1-14 the boxes. */
+  private loadedBox(box: number): (PartyMon | BoxMon)[] {
+    return box ? this.state.storage.boxes[box - 1] : this.state.party;
+  }
+  private loadedBoxName(box: number) {
+    return box
+      ? this.boxName(box - 1)
+      : this.string(PC["BillsPC_BoxName.PartyPKMN"]);
+  }
+  /** Choose the party or a box (left and right in the original). */
+  private *chooseLoadedBox(prompt: string, selected: number): Gen<number> {
+    const boxes = Array.from({ length: NUM_BOXES + 1 }, (_, box) => box);
+    return yield* this.menu(
+      [prompt],
+      boxes.map((box) => this.loadedBoxName(box)),
+      boxes.map((box) => `${this.loadedBox(box).length}/${box ? MONS_PER_BOX : PARTY_LENGTH}`),
+      selected,
+    );
+  }
+  /** _MovePKMNWithoutMail: choose a Pokémon in the party or a box, MOVE it
+   * (STATS shows it) and choose where it goes; the list is presented per
+   * box instead of with left and right. */
+  private *moveWithoutMail(): Gen {
+    const data = this.host.data;
+    const choose = this.string(PC.PCString_ChooseaPKMN),
+      where = this.string(PC.PCString_MoveToWhere),
+      cancel = this.string(PC["BillsPC_RefreshTextboxes.CancelString"]),
+      options = this.strings(PC["_MovePKMNWithoutMail.MenuData"] + 2, 3);
+    let loaded = this.state.storage.current + 1;
+    for (;;) {
+      const from = yield* this.chooseLoadedBox(choose, loaded);
+      if (from < 0) return;
+      loaded = from;
+      const list = this.loadedBox(from);
+      const index = yield* this.menu(
+        [`${this.loadedBoxName(from)}\n${choose}`],
+        [...list.map((mon) => mon.nickname), cancel],
+        this.monDetails(list),
+      );
+      if (index < 0 || index >= list.length) continue;
+      const action = yield* this.menu([this.string(PC.PCString_WhatsUp)], options);
+      if (action === 1) {
+        const mon = list[index];
+        yield {
+          kind: "stats",
+          mon: from ? bufferMon(data, mon as BoxMon) : structuredClone(mon as PartyMon),
+        };
+        continue;
+      }
+      if (action !== 0) continue;
+      // BillsPC_CheckMail_PreventBlackout, even within the party.
+      if (!from && !(yield* this.partyMonMayLeave(index))) continue;
+      // Where: a box, then the position to insert before.
+      for (;;) {
+        const to = yield* this.chooseLoadedBox(where, from);
+        if (to < 0) break;
+        const destination = this.loadedBox(to);
+        const position = yield* this.menu(
+          [`${this.loadedBoxName(to)}\n${where}`],
+          [...destination.map((mon) => mon.nickname), "▶"],
+          this.monDetails(destination),
+          destination.length,
+        );
+        if (position < 0) continue;
+        // BillsPC_CheckSpaceInDestination
+        if (
+          to !== from &&
+          destination.length >= (to ? MONS_PER_BOX : PARTY_LENGTH)
+        ) {
+          yield* this.placeString(this.string(PC.PCString_TheresNoRoom));
+          continue;
+        }
+        yield* this.placeString(
+          this.string(PC["MovePKMNWithoutMail_InsertMon.Saving_LeaveOn"]),
+          10,
+        );
+        this.insertMon(from, index, to, position);
+        loaded = to;
+        break;
+      }
+    }
+  }
+  /** MovePKMNWithoutMail_InsertMon: remove, then insert before `position`
+   * (one earlier when moving down the same list, .CheckTrivialMove). A
+   * boxed Pokémon joining the party gets CalcBufferMonStats' full HP;
+   * InsertPokemonIntoBox restores the PP. */
+  private insertMon(from: number, index: number, to: number, position: number) {
+    const data = this.host.data;
+    const source = this.loadedBox(from);
+    const [moved] = source.splice(index, 1);
+    if (from === to && index < position) position--;
+    if (to) {
+      const stored = from ? (moved as BoxMon) : toBoxMon(moved as PartyMon);
+      restorePP(data, stored);
+      this.state.storage.boxes[to - 1].splice(position, 0, stored);
+    } else
+      this.state.party.splice(
+        position,
+        0,
+        from ? bufferMon(data, moved as BoxMon) : (moved as PartyMon),
+      );
+  }
+
   /** BillsPC_CheckMail_PreventBlackout for a party Pokémon: the last one,
    * or the last that has not fainted, stays. No MAIL exists yet. */
   private *partyMonMayLeave(index: number): Gen<boolean> {

src/game/scripts/start-menu.ts

@@ -1,6 +1,6 @@
 import type { RomReader } from "../rom/reader";
 import type { PokemonData } from "../rom/pokemon";
-import { BATTLE, ENGINE_FLAGS, MENU, RAM } from "../rom/profile";
+import { BATTLE, ENGINE_FLAGS, MENU, OVERWORLD, RAM } from "../rom/profile";
 import { C } from "../battle/constants";
 import {
   changedHappiness,
@@ -79,6 +79,22 @@ export interface MenuCursors {
   pocket: number;
 }
 
+/** The world's verdict on a field move chosen from the party menu: a
+ * script to run once the menu closes (with the context the world checked),
+ * the messages of a failed attempt, or a notice for what is not ported. */
+export type MenuFieldMove =
+  | {
+      script: number;
+      fieldMove: {
+        mon: number;
+        surfState?: number;
+        block?: { x: number; y: number; block: number };
+      };
+      wild?: { species: number; level: number };
+    }
+  | { texts: number[] }
+  | { notice: string };
+
 /** What the start menu needs from the world. */
 export interface StartMenuHost {
   reader: RomReader;
@@ -86,11 +102,13 @@ export interface StartMenuHost {
   text(): TextContext;
   /** BikeFunction: the script that getting on or off the Bicycle queues
    * here, or undefined when .CheckEnvironment refuses it. */
-  bicycleScript(state: ScriptState): number | undefined;
+  bicycleScript(state: ScriptState, select: boolean): number | undefined;
   /** wTimeOfDay: morning 0, day 1, night 2. */
   timeOfDay(): number;
   /** GetWorldMapLocation for the current map (LevelUpHappinessMod). */
   landmark(): number;
+  /** A field move's checks for party slot `mon`, on the menu's draft. */
+  fieldMove(state: ScriptState, mon: number, move: number): MenuFieldMove;
 }
 
 /** The overworld start menu (engine/menus/start_menu.asm) with its
@@ -105,6 +123,8 @@ export class StartMenuRun {
    * closes, with the item named as UseItem names it. */
   deferred?: number;
   deferredItem?: number;
+  /** The field move context and wild Pokémon a queued script needs. */
+  deferredMove?: Extract<MenuFieldMove, { script: number }>;
   /** The menu cursors kept in work RAM between openings. */
   readonly cursors: MenuCursors;
   private strings: Record<number, string> = {};
@@ -112,14 +132,19 @@ export class StartMenuRun {
   private iterator: Gen;
   private done = false;
 
+  /** wUsingItemWithSelect: the registered item is being used. */
+  private usingSelect = false;
+
+  /** `select` runs SelectMenu (the Select button) instead of StartMenu. */
   constructor(
     state: ScriptState,
     private host: StartMenuHost,
     cursors: MenuCursors = { start: 0, party: 0, pocket: 0 },
+    select = false,
   ) {
     this.state = copyScriptState(state);
     this.cursors = { ...cursors };
-    this.iterator = this.run();
+    this.iterator = select ? this.selectMenu() : this.run();
   }
 
   /** Advance until the next effect, or undefined when the menu closed. */
@@ -270,6 +295,55 @@ export class StartMenuRun {
     }
   }
 
+  // -------------------------------------------------------- select menu
+
+  /** SelectMenu: use the registered item, or suggest registering one. */
+  private *selectMenu(): Gen {
+    const registered = this.checkRegisteredItem();
+    if (!registered) return yield* this.print(MENU.MayRegisterItemText);
+    const { item, index } = registered;
+    // UseRegisteredItem by the item's field menu.
+    const menu = this.data.itemFieldMenu(item);
+    if (menu < ITEMMENU_CURRENT) return yield* this.print(MENU.ItemsOakWarningText);
+    this.usingSelect = menu === ITEMMENU_CLOSE;
+    const used = yield* this.doItemEffect(index, item);
+    this.usingSelect = false;
+    if (menu === ITEMMENU_CLOSE && used === false)
+      yield* this.print(MENU.ItemsOakWarningText);
+  }
+  /** CheckRegisteredItem: the registered item if it is still in its slot
+   * (or, for key items, anywhere in the pocket); otherwise the
+   * registration is cleared. A registered ball is never found, because
+   * .CheckBall's slot test is inverted. */
+  private checkRegisteredItem(): { item: number; index: number } | undefined {
+    const registered = this.state.registeredItem,
+      bag = this.state.bag;
+    const pocket = registered.which >> 6,
+      index = (registered.which & 0x3f) - 1;
+    let found: { item: number; index: number } | undefined;
+    if (registered.which) {
+      if (pocket === 0) {
+        if (index < bag.items.length && bag.items[index].item === registered.item)
+          found = { item: registered.item, index };
+      } else if (pocket === KEY_ITEM_POCKET) {
+        if (bag.keyItems.includes(registered.item))
+          found = { item: registered.item, index: -1 };
+      }
+    }
+    if (!found) this.state.registeredItem = { which: 0, item: 0 };
+    return found;
+  }
+  /** RegisterItem: CANT_SELECT items cannot be registered. */
+  private *registerItem(pocket: PocketIndex, index: number, item: number): Gen {
+    if (this.data.itemUnselectable(item)) return yield* this.print(MENU.CantRegisterText);
+    this.state.registeredItem = {
+      which: ((pocket << 6) & 0xc0) | ((index + 1) & 0x3f),
+      item,
+    };
+    this.nameItem(item);
+    yield* this.print(MENU.RegisteredItemText);
+  }
+
   // --------------------------------------------------------- party menu
 
   /** The party menu with PlacePartyMenuText's prompt. Returns the party
@@ -314,7 +388,7 @@ export class StartMenuRun {
     for (;;) {
       const slot = yield* this.partyMenu(PARTYMENUACTION_CHOOSE_POKEMON);
       if (slot < 0) return false;
-      yield* this.pokemonActionSubmenu(slot);
+      if (yield* this.pokemonActionSubmenu(slot)) return true;
     }
   }
 
@@ -353,8 +427,9 @@ export class StartMenuRun {
     return this.stringList(MENU.MonMenuOptionStrings, value)[value - 1];
   }
 
-  /** PokemonActionSubmenu (MonSubmenu); B is CANCEL. */
-  private *pokemonActionSubmenu(slot: number): Gen {
+  /** PokemonActionSubmenu (MonSubmenu); B is CANCEL. Returns true when a
+   * field move closes every menu to run its script. */
+  private *pokemonActionSubmenu(slot: number): Gen<boolean> {
     const mon = this.state.party[slot];
     const items = this.monSubmenuItems(mon);
     const choice = yield* this.menu(
@@ -366,22 +441,77 @@ export class StartMenuRun {
       case MONMENUITEM_STATS:
         // OpenPartyStats
         yield { kind: "stats", mon };
-        return;
+        break;
       case MONMENUITEM_SWITCH:
-        return yield* this.switchPartyMons(slot);
+        yield* this.switchPartyMons(slot);
+        break;
       case MONMENUITEM_ITEM:
-        return yield* this.giveTakePartyMonItem(slot);
+        yield* this.giveTakePartyMonItem(slot);
+        break;
       case MONMENUITEM_MOVE:
-        return yield* this.managePokemonMoves(slot);
+        yield* this.managePokemonMoves(slot);
+        break;
       case MONMENUITEM_CANCEL:
-        return;
+        break;
       case MONMENUITEM_MAIL:
-        return yield* this.notice(`MAIL ${NOT_PORTED}`);
+        yield* this.notice(`MAIL ${NOT_PORTED}`);
+        break;
       default:
-        return yield* this.notice(
-          `Using ${this.monMenuString(item)} from the menu ${NOT_PORTED}`,
-        );
+        return yield* this.fieldMove(slot, item);
     }
+    return false;
+  }
+
+  /** MonMenu_Cut and the other field moves: Softboiled and Milk Drink run
+   * here; the others ask the world, which checks the map. */
+  private *fieldMove(slot: number, item: number): Gen<boolean> {
+    const r = this.reader;
+    let p = MENU.MonMenuOptions;
+    while (r.byte(p + 1) !== item) p += 3;
+    const move = r.byte(p + 2);
+    if (move === C.SOFTBOILED || move === C.MILK_DRINK) {
+      yield* this.softboiledMilkDrink(slot);
+      return false;
+    }
+    const result = this.host.fieldMove(this.state, slot, move);
+    if ("script" in result) {
+      this.deferred = result.script;
+      this.deferredMove = result;
+      return true;
+    }
+    if ("notice" in result) yield* this.notice(result.notice);
+    else for (const text of result.texts) yield* this.print(text);
+    return false;
+  }
+
+  /** MonMenu_Softboiled_MilkDrink: the user needs more than a fifth of
+   * its maximum HP, and gives that much to another Pokémon that has not
+   * fainted and is not at full HP. */
+  private *softboiledMilkDrink(user: number): Gen {
+    const party = this.state.party,
+      source = party[user];
+    const fifth = Math.floor(source.stats[0] / 5);
+    if (source.hp <= fifth) {
+      yield* this.print(MENU["MonMenu_Softboiled_MilkDrink.PokemonNotEnoughHPText"]);
+      return;
+    }
+    for (;;) {
+      const target = yield* this.partyMenu(PARTYMENUACTION_HEALING_ITEM);
+      if (target < 0) break;
+      const mon = party[target];
+      if (target === user || !mon.hp || mon.hp >= mon.stats[0]) {
+        yield* this.print(
+          OVERWORLD["Softboiled_MilkDrinkFunction.ItemCantUseOnMonText"],
+        );
+        continue;
+      }
+      source.hp = Math.max(0, source.hp - fifth);
+      this.setHP(mon, restoreHealth(mon.hp, mon.stats[0], fifth));
+      yield* this.itemActionText(target, C.PARTYMENUTEXT_HEAL_HP);
+      break;
+    }
+    // .skip: the cursor returns to the user.
+    this.cursors.party = user + 1;
   }
 
   /** SwitchPartyMons and _SwitchPartyMons: "Move to where?" without a
@@ -591,7 +721,7 @@ export class StartMenuRun {
         yield* this.tossMenu(pocket, index, item);
         return false;
       case "sel":
-        yield* this.notice(`Registering items for SELECT ${NOT_PORTED}`);
+        yield* this.registerItem(pocket, index, item);
         return false;
       default:
         return false;
@@ -660,13 +790,16 @@ export class StartMenuRun {
     }
     const used = yield* this.doItemEffect(index, item);
     if (menu !== ITEMMENU_CLOSE) return false;
-    if (!used) yield* this.print(BATTLE.OakThisIsntTheTimeText);
-    return used;
+    if (used === false) yield* this.print(BATTLE.OakThisIsntTheTimeText);
+    return used === true;
   }
 
   /** _DoItemEffect: ItemEffects by ROM address. Returns
-   * wItemEffectSucceeded. */
-  private *doItemEffect(index: number, item: number): Gen<boolean> {
+   * wItemEffectSucceeded, or "unported" after a notice. */
+  private *doItemEffect(
+    index: number,
+    item: number,
+  ): Gen<boolean | "unported"> {
     const r = this.reader;
     this.nameItem(item);
     const effect = r.near(
@@ -722,7 +855,7 @@ export class StartMenuRun {
       case MENU.EvoStoneEffect:
         return yield* this.evoStoneEffect(use);
       case MENU.BicycleEffect: {
-        const script = this.host.bicycleScript(this.state);
+        const script = this.host.bicycleScript(this.state, this.usingSelect);
         if (script === undefined) return false;
         this.deferred = script;
         this.deferredItem = item;
@@ -730,7 +863,7 @@ export class StartMenuRun {
       }
     }
     yield* this.notice(`Using ${this.data.itemName(item)} ${NOT_PORTED}`);
-    return false;
+    return "unported";
   }
 
   /** UseItem_SelectMon: the party menu for an item. The party index, or

src/game/scripts/text.ts

@@ -85,7 +85,7 @@ export interface TextContext {
   battle?: { turn: number; player: string; enemy: string; enemyPrefix: string };
   /** Native handlers for text_asm, keyed by the command's ROM offset. They
    * return where text continues, as the original routine returns in hl. */
-  asm?: (offset: number) => number;
+  asm?: (offset: number) => number | undefined;
 }
 
 export const defaultTextContext = (player: string): TextContext => ({

src/game/world/constants.ts

@@ -51,6 +51,7 @@ export const OW = {
   ENGINE_HIVEBADGE: 28,
   ENGINE_PLAINBADGE: 29,
   ENGINE_FOGBADGE: 30,
+  ENGINE_STORMBADGE: 32,
   ENGINE_GLACIERBADGE: 33,
   ENGINE_RISINGBADGE: 34,
   // Map environments (constants/map_data_constants.asm).
@@ -99,6 +100,14 @@ export const OW = {
   WHIRLPOOL: 250,
   WATERFALL: 127,
   HEADBUTT: 29,
+  FLY: 0x13,
+  DIG: 0x5b,
+  TELEPORT: 0x64,
+  FLASH: 0x94,
+  SWEET_SCENT: 0xe6,
+  ROCK_SMASH: 0xf9,
+  // SpriteMovementData (constants/map_object_constants.asm).
+  SPRITEMOVEDATA_SMASHABLE_ROCK: 0x18,
   BICYCLE: 7,
   PIKACHU: 25,
   EGG: 0xfd,

src/game/world/types.ts

@@ -57,6 +57,8 @@ export interface GameMap {
   tileset: number;
   environment: number;
   paletteMode: number;
+  /** The map attributes' ROM offset, which some routines compare. */
+  attributes?: number;
   blocks: Uint8Array;
   warps: Warp[];
   backgroundEvents: BackgroundEvent[];

src/game/world/world.ts

@@ -7,6 +7,7 @@ import { CrystalAssets } from "../rom/assets";
 import { TrainerData } from "../rom/trainers";
 import {
   ENGINE_FLAGS,
+  EVENTS,
   INITIAL_POSITION,
   NUM_FRUIT_TREES,
   OVERWORLD,
@@ -27,7 +28,11 @@ import {
   type ScriptState,
 } from "../scripts/interpreter";
 import { IntroRun } from "../scripts/intro";
-import { StartMenuRun, type MenuCursors } from "../scripts/start-menu";
+import {
+  StartMenuRun,
+  type MenuCursors,
+  type MenuFieldMove,
+} from "../scripts/start-menu";
 import { PartyEvolution } from "../scripts/evolution";
 import type { MovementPose, MovementStep } from "../scripts/movement";
 import { emptyBag, validBag, type Bag, type ItemSlot } from "../party/bag";
@@ -107,6 +112,8 @@ export interface NativeSave {
   /** STATUSFLAGS_FLASH_F and STATUSFLAGS_NO_WILD_ENCOUNTERS_F. */
   flash: boolean;
   noWildEncounters: boolean;
+  /** wWhichRegisteredItem and wRegisteredItem, for Select. */
+  registeredItem: { which: number; item: number };
 }
 
 /** A random byte from the platform's secure generator. */
@@ -1364,7 +1371,20 @@ export class GameWorld {
     )
       return;
     if (isIce(collision)) return;
-    // GetMapEncounterRate: CheckOnWater picks the water rate.
+    const table = this.encounterTable(state);
+    if (!(this.random() < table.rate)) return;
+    const chosen = this.chooseWildEncounter(table);
+    if (!chosen) return;
+    if (!state.party.some((mon) => mon.hp > 0)) return;
+    this.startScript(SYMBOLS.wildBattleScript, PLAYER, {
+      committedPosition: previous,
+      wild: chosen,
+    });
+  }
+  /** GetMapEncounterRate: CheckOnWater picks the water table and rate,
+   * which a Cleanse Tag halves. */
+  private encounterTable(state: ScriptState) {
+    const collision = this.assets.collision(this.map, this.x, this.y);
     const water = this.assets.permission(collision) === OW.WATER_TILE,
       kanto = this.inKanto();
     const grass = water
@@ -1376,10 +1396,17 @@ export class GameWorld {
     let rate = (water ? sea?.rate : grass?.rates[this.clockTimeOfDay]) ?? 0;
     // ApplyCleanseTagEffectOnEncounterRate
     if (state.party.some((mon) => mon.item === C.CLEANSE_TAG)) rate >>= 1;
-    if (!(this.random() < rate)) return;
-    // ChooseWildEncounter: 1-100 against GrassMonProbTable or
-    // WaterMonProbTable, whose entries are (percent, slot offset).
-    if (!grass && !sea) return;
+    return { water, grass, sea, rate };
+  }
+  /** ChooseWildEncounter: 1-100 against GrassMonProbTable or
+   * WaterMonProbTable, whose entries are (percent, slot offset); surfing
+   * varies the level. Undefined when no valid Pokémon is chosen. */
+  private chooseWildEncounter({
+    water,
+    grass,
+    sea,
+  }: ReturnType<GameWorld["encounterTable"]>) {
+    if (!grass && !sea) return undefined;
     let roll: number;
     do roll = this.random();
     while (roll >= 100);
@@ -1399,12 +1426,167 @@ export class GameWorld {
     }
     // ValidateTempWildMonSpecies; Unown needs unlocked Unown (not ported).
     if (!chosen.species || chosen.species > 251 || chosen.species === C.UNOWN)
-      return;
-    if (!state.party.some((mon) => mon.hp > 0)) return;
-    this.startScript(SYMBOLS.wildBattleScript, PLAYER, {
-      committedPosition: previous,
-      wild: chosen,
-    });
+      return undefined;
+    return chosen;
+  }
+  /** CanEncounterWildMon: wildoff; caves and dungeons need no grass; never
+   * on ice. */
+  private canEncounterWildMon(state: ScriptState) {
+    const map = this.map,
+      collision = this.assets.collision(map, this.x, this.y);
+    return (
+      !state.noWildEncounters &&
+      (map.environment === OW.CAVE ||
+        map.environment === OW.DUNGEON ||
+        this.assets.grassCollisions().includes(collision)) &&
+      !isIce(collision)
+    );
+  }
+
+  /** A field move chosen from the party menu (CutFunction, SurfFunction and
+   * the rest in engine/events/overworld.asm), checked on the menu's draft
+   * for party slot `mon`: a script queued for when the menu closes, the
+   * messages of a failed attempt, or a notice for what is not ported. */
+  private menuFieldMove(
+    state: ScriptState,
+    mon: number,
+    move: number,
+  ): MenuFieldMove {
+    const [dx, dy] = VECTORS[this.player.direction];
+    const x = this.player.x + dx,
+      y = this.player.y + dy;
+    const tile = this.assets.collision(this.map, x, y) ?? 0;
+    const env = this.map.environment,
+      outdoors = env === OW.TOWN || env === OW.ROUTE;
+    const failed = { texts: [OVERWORLD["FieldMoveFailed.CantUseItemText"]] };
+    const badge = (flag: number) =>
+      state.flags.has(flag)
+        ? undefined
+        : { texts: [OVERWORLD["CheckBadge.BadgeRequiredText"]] };
+    const facingObject = () =>
+      this.objects().find((object) => object.x === x && object.y === y);
+    switch (move) {
+      case OW.CUT: {
+        const block = this.fieldMoveBlock(x, y, tile, "cut");
+        return (
+          badge(OW.ENGINE_HIVEBADGE) ??
+          (block
+            ? {
+                script: OVERWORLD.Script_CutFromMenu,
+                fieldMove: { mon, block },
+              }
+            : { texts: [OVERWORLD.CutNothingText] })
+        );
+      }
+      case OW.SURF: {
+        const noBadge = badge(OW.ENGINE_FOGBADGE);
+        if (noBadge) return noBadge;
+        const cant = { texts: [OVERWORLD.CantSurfText] };
+        if (state.flags.has(OW.ENGINE_ALWAYS_ON_BIKE)) return cant;
+        if (
+          state.playerState === OW.PLAYER_SURF ||
+          state.playerState === OW.PLAYER_SURF_PIKA
+        )
+          return { texts: [OVERWORLD.AlreadySurfingText] };
+        const current = this.assets.collision(this.map, this.x, this.y);
+        if (
+          this.assets.permission(tile) !== OW.WATER_TILE ||
+          this.sideBlocked(current, tile, this.player.direction) ||
+          facingObject()
+        )
+          return cant;
+        return {
+          script: OVERWORLD.SurfFromMenuScript,
+          fieldMove: {
+            mon,
+            // GetSurfType: Pikachu surfs on its own sprite.
+            surfState:
+              state.party[mon].species === OW.PIKACHU
+                ? OW.PLAYER_SURF_PIKA
+                : OW.PLAYER_SURF,
+          },
+        };
+      }
+      case OW.STRENGTH:
+        return (
+          badge(OW.ENGINE_PLAINBADGE) ?? {
+            script: OVERWORLD.Script_StrengthFromMenu,
+            fieldMove: { mon },
+          }
+        );
+      case OW.FLASH: {
+        const noBadge = badge(OW.ENGINE_ZEPHYRBADGE);
+        if (noBadge) return noBadge;
+        // SpecialAerodactylChamber opens its wall; otherwise the map must
+        // be dark (DARKNESS_PALSET).
+        const chamber =
+          this.map.attributes ===
+          OVERWORLD.RuinsOfAlphAerodactylChamber_MapAttributes;
+        if (chamber) state.events.add(EVENTS.wallOpenedInAerodactylChamber);
+        return chamber || this.timeOfDay === 3
+          ? { script: OVERWORLD.Script_UseFlash, fieldMove: { mon } }
+          : failed;
+      }
+      case OW.WHIRLPOOL: {
+        const noBadge = badge(OW.ENGINE_GLACIERBADGE);
+        if (noBadge) return noBadge;
+        const block = isWhirlpool(tile)
+          ? this.fieldMoveBlock(x, y, tile, "whirlpool")
+          : undefined;
+        return block
+          ? {
+              script: OVERWORLD.Script_WhirlpoolFromMenu,
+              fieldMove: { mon, block },
+            }
+          : failed;
+      }
+      case OW.WATERFALL: {
+        const noBadge = badge(OW.ENGINE_RISINGBADGE);
+        if (noBadge) return noBadge;
+        // CheckMapCanWaterfall: facing up at a waterfall tile.
+        return this.player.direction === "up" &&
+          (tile === OW.COLL_WATERFALL || tile === OW.COLL_CURRENT_DOWN)
+          ? { script: OVERWORLD.Script_WaterfallFromMenu, fieldMove: { mon } }
+          : failed;
+      }
+      case OW.FLY:
+        return (
+          badge(OW.ENGINE_STORMBADGE) ??
+          (outdoors ? { notice: "The Fly map is not ported yet." } : failed)
+        );
+      case OW.DIG:
+        return env === OW.CAVE || env === OW.DUNGEON
+          ? { notice: "Digging out of a cave is not ported yet." }
+          : { texts: [OVERWORLD["EscapeRopeOrDig.CantUseDigText"]] };
+      case OW.TELEPORT:
+        return outdoors && state.lastSpawnMap !== null
+          ? { notice: "Teleport is not ported yet." }
+          : { texts: [OVERWORLD["TeleportFunction.CantUseTeleportText"]] };
+      case OW.HEADBUTT:
+        return tile === OW.COLL_HEADBUTT_TREE ||
+          tile === OW.COLL_HEADBUTT_TREE_1D
+          ? { notice: "Headbutt trees are not ported yet." }
+          : failed;
+      case OW.ROCK_SMASH:
+        return facingObject()?.movement === OW.SPRITEMOVEDATA_SMASHABLE_ROCK
+          ? { notice: "Smashing rocks is not ported yet." }
+          : failed;
+      case OW.SWEET_SCENT: {
+        // SweetScentEncounter, drawn now: no rate roll, and no battle
+        // without a rate or a valid Pokémon.
+        let wild: { species: number; level: number } | undefined;
+        if (this.canEncounterWildMon(state)) {
+          const table = this.encounterTable(state);
+          if (table.rate) wild = this.chooseWildEncounter(table);
+        }
+        return {
+          script: OVERWORLD["SweetScentFromMenu.SweetScent"],
+          fieldMove: { mon },
+          wild,
+        };
+      }
+    }
+    return { notice: "This field move is not ported yet." };
   }
 
   /** IsInJohto: Kanto landmarks start at KANTO_LANDMARK; the Fast Ship
@@ -1655,9 +1837,13 @@ export class GameWorld {
       text: () => this.host(PLAYER).text(),
     };
   }
+  /** Select in PlayerEvents (SelectMenuScript): the registered item. */
+  useSelect(): boolean {
+    return this.openStartMenu(true);
+  }
   /** Start in PlayerEvents (StartMenuScript): the start menu opens while
    * the player stands still. Its changes commit when it closes. */
-  openStartMenu(): boolean {
+  openStartMenu(select = false): boolean {
     if (this.busy || this.introPending) return false;
     this.clearNotice();
     this.script = {
@@ -1667,11 +1853,14 @@ export class GameWorld {
           reader: this.assets.reader,
           data: this.assets.pokemon,
           text: () => this.host(PLAYER).text(),
-          bicycleScript: (state) => this.bicycleScript(state),
+          bicycleScript: (state, select) => this.bicycleScript(state, select),
           timeOfDay: () => this.clockTimeOfDay,
           landmark: () => this.assets.map(this.mapId).landmark,
+          fieldMove: (state, mon, move) =>
+            this.menuFieldMove(state, mon, move),
         },
         this.menuCursors,
+        select,
       ),
       committed: this.save(),
       rollback: {
@@ -2396,12 +2585,17 @@ export class GameWorld {
       this.sceneCheck = true;
     if (script.run instanceof StartMenuRun) this.menuCursors = script.run.cursors;
     if (script.run.deferred !== undefined)
-      this.startScript(script.run.deferred, PLAYER, {
-        usedItem:
-          script.run instanceof StartMenuRun
-            ? script.run.deferredItem
-            : undefined,
-      });
+      this.startScript(
+        script.run.deferred,
+        PLAYER,
+        script.run instanceof StartMenuRun
+          ? {
+              usedItem: script.run.deferredItem,
+              fieldMove: script.run.deferredMove?.fieldMove,
+              wild: script.run.deferredMove?.wild,
+            }
+          : {},
+      );
   }
   private abortScript(error: unknown) {
     const script = this.script!;
@@ -3228,7 +3422,7 @@ export class GameWorld {
   }
   /** BikeFunction.TryBike: the script QueueScript runs, or undefined when
    * .CheckEnvironment or the player's state refuses the Bicycle. */
-  private bicycleScript(state: ScriptState): number | undefined {
+  private bicycleScript(state: ScriptState, select = false): number | undefined {
     const map = this.map;
     const outdoors =
       map.environment === OW.TOWN || map.environment === OW.ROUTE;
@@ -3239,12 +3433,17 @@ export class GameWorld {
       this.assets.permission(this.assets.collision(map, this.x, this.y)) ===
         OW.LAND_TILE;
     if (!allowed) return undefined;
+    // .CheckIfRegistered: Select uses the scripts without a message.
     if (state.playerState === OW.PLAYER_NORMAL)
-      return OVERWORLD.Script_GetOnBike;
+      return select
+        ? OVERWORLD.Script_GetOnBike_Register
+        : OVERWORLD.Script_GetOnBike;
     if (state.playerState === OW.PLAYER_BIKE)
       return state.flags.has(OW.ENGINE_ALWAYS_ON_BIKE)
         ? OVERWORLD.Script_CantGetOffBike
-        : OVERWORLD.Script_GetOffBike;
+        : select
+          ? OVERWORLD.Script_GetOffBike_Register
+          : OVERWORLD.Script_GetOffBike;
     return undefined;
   }
 
@@ -3484,6 +3683,7 @@ export class GameWorld {
       backupWarp: state.backupWarp && { ...state.backupWarp },
       flash: state.flash,
       noWildEncounters: state.noWildEncounters,
+      registeredItem: { ...state.registeredItem },
     };
   }
   restore(value: unknown) {
@@ -3579,7 +3779,10 @@ export class GameWorld {
           !/^\d{1,2}:\d{1,3}$/.test(save.backupWarp.map) ||
           !integer(save.backupWarp.warp, 1, 254))) ||
       typeof save.flash !== "boolean" ||
-      typeof save.noWildEncounters !== "boolean"
+      typeof save.noWildEncounters !== "boolean" ||
+      !save.registeredItem ||
+      !integer(save.registeredItem.which, 0, 255) ||
+      !integer(save.registeredItem.item, 0, 255)
     ) {
       throw new Error(
         "Invalid native save. Emulator snapshots cannot be imported into this port.",
@@ -3641,6 +3844,7 @@ export class GameWorld {
       backupWarp: save.backupWarp && { ...save.backupWarp },
       flash: save.flash,
       noWildEncounters: save.noWildEncounters,
+      registeredItem: { ...save.registeredItem },
       specialPhoneCall: save.specialPhoneCall,
       rivalName: save.rivalName,
     };
@@ -3738,6 +3942,9 @@ export function migrateSave(
       ...(!Object.hasOwn(save, "noWildEncounters") && {
         noWildEncounters: false,
       }),
+      ...(!Object.hasOwn(save, "registeredItem") && {
+        registeredItem: { which: 0, item: 0 },
+      }),
       ...(!Object.hasOwn(save, "intro") && { intro: false }),
       // Clocks saved before InitClock was ported follow the device time.
       ...(save.clock !== null &&
@@ -3779,6 +3986,7 @@ export function migrateSave(
     backupWarp: null,
     flash: false,
     noWildEncounters: false,
+    registeredItem: { which: 0, item: 0 },
     intro: false,
   } as unknown as NativeSave;
 }

src/main.ts

@@ -1,5 +1,4 @@
 import { drawTownMap } from "./game/rendering/town-map";
-import { OW } from "./game/world/constants";
 import "./ui/styles.css";
 import { renderShell } from "./ui/shell";
 import { bindTabs } from "./ui/tabs";
@@ -48,7 +47,6 @@ function showWorld(world: GameWorld) {
   get("game-notice").textContent = world.notice;
   showBattle(world);
   showStatsScreen(world);
-  showFieldMenu(world);
   get("town-map-view").hidden = !world.townMap;
   if (world.townMap)
     drawTownMap(get<HTMLCanvasElement>("town-map-canvas"), world);
@@ -438,64 +436,14 @@ let statsView: { slot?: number; page: number } | undefined;
 let battleCursor = 0;
 let battleSelectionKey = "";
 
-let fieldCursor = 0;
-function fieldButtons() {
-  return [
-    ...get("field-items").querySelectorAll<HTMLButtonElement>(
-      "button:not(:disabled)",
-    ),
-  ];
-}
-function showFieldMenu(world: GameWorld) {
-  const panel = get("field-menu");
-  panel.hidden = !runtime.fieldMenuOpen;
-  if (panel.hidden) return;
-  const buttons = world.state.bag.keyItems.map((item) => {
-    const button = document.createElement("button");
-    button.textContent = world.assets.pokemon.itemName(item);
-    button.disabled = item !== OW.BICYCLE;
-    button.onclick = () => {
-      if (session.state !== "playing") return;
-      runtime.useBicycle();
-      canvas.focus({ preventScroll: true });
-    };
-    return button;
-  });
-  const close = document.createElement("button");
-  close.textContent = "CLOSE";
-  close.onclick = () => {
-    runtime.fieldMenuOpen = false;
-    showFieldMenu(world);
-    canvas.focus();
-  };
-  get("field-items").replaceChildren(...buttons, close);
-  fieldButtons().forEach((button, i) =>
-    button.classList.toggle("battle-selected", i === fieldCursor),
-  );
-}
+/** Start opens the start menu and Select uses the registered item, while
+ * the player stands still (StartMenuScript and SelectMenuScript). */
 function handleFieldInput(button: Button): boolean {
   const world = runtime.world;
-  if (!world || world.battle) return false;
-  // Start opens the start menu; Select, standing in for a registered
-  // item, opens the Key Items shortcut.
-  if (button === "start" && !runtime.fieldMenuOpen && !world.busy) {
-    runtime.openStartMenu();
-    return true;
-  }
-  if (button === "select" && !world.busy) {
-    runtime.fieldMenuOpen = !runtime.fieldMenuOpen;
-    fieldCursor = 0;
-    return true;
-  }
-  if (!runtime.fieldMenuOpen) return false;
-  if (button === "b") runtime.fieldMenuOpen = false;
-  else if (button === "a") fieldButtons()[fieldCursor]?.click();
-  else if (["up", "down", "left", "right"].includes(button)) {
-    const length = fieldButtons().length;
-    fieldCursor =
-      (fieldCursor + (button === "up" || button === "left" ? -1 : 1) + length) %
-      length;
-  }
+  if (!world || world.battle || world.busy) return false;
+  if (button === "start") runtime.openStartMenu();
+  else if (button === "select") runtime.useSelect();
+  else return false;
   return true;
 }
 

src/ui/shell.ts

@@ -33,7 +33,6 @@ export function renderShell(root: HTMLElement) {
               </div>
               <div id="stats-screen" class="stats-screen" hidden aria-label="Pokémon stats"><div class="stats-top"><canvas id="stats-pic" width="56" height="56" role="img"></canvas><div id="stats-header" class="stats-header"></div></div><div id="stats-page" class="stats-page" aria-live="polite"></div><div class="stats-nav"><button id="stats-prev" aria-label="Previous page">◀</button><span id="stats-page-number"></span><button id="stats-next" aria-label="Next page">▶</button><button id="stats-close">Close</button></div></div>
               <div id="town-map-view" class="town-map-view" hidden aria-label="Town Map"><canvas id="town-map-canvas" width="160" height="144" role="img" aria-label="Town Map"></canvas><button id="town-map-close">Close map</button></div>
-              <div id="field-menu" class="field-menu" hidden aria-label="Pack"><p>KEY ITEMS</p><div id="field-items"></div></div>
               <div id="mart" class="mart" hidden aria-label="Poké Mart">
                 <p id="mart-money" class="mart-money"></p>
                 <div class="mart-box"><p id="mart-prompt" aria-live="polite"></p><div id="mart-tabs" class="pack-tabs" aria-label="Pockets" hidden></div><div id="mart-menu" class="mart-menu"></div></div>

src/ui/styles.css

@@ -1117,30 +1117,6 @@ dialog dd {
   }
 }
 
-.field-menu {
-  position: absolute;
-  inset: 1rem 1rem auto auto;
-  z-index: 6;
-  max-height: calc(100% - 2rem);
-  overflow: auto;
-  min-width: 10rem;
-  padding: 1rem;
-  border: 2px solid #27332a;
-  border-radius: 0.4rem;
-  background: #f8f4df;
-  color: #27332a;
-}
-.field-menu[hidden] {
-  display: none;
-}
-.field-menu p {
-  margin: 0 0 0.5rem;
-}
-#field-items {
-  display: grid;
-  gap: 0.3rem;
-}
-
 .town-map-view {
   position: absolute;
   inset: 0;