Add the Johto and Kanto atlas to the Map tab

The Map tab draws the region's Town Map from the ROM with the player's
landmark, the visited flypoints as Fly destinations and the landmarks
whose maps are ported. Kanto opens with the Fly map's Indigo Plateau
rule. Landmark positions and flypoints are compared with the pinned
PRET source.

Closes #36

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

tests/atlas.test.ts

@@ -0,0 +1,132 @@
+import { describe, expect, it } from "vitest";
+import { existsSync, readFileSync } from "node:fs";
+import { CrystalAssets } from "../src/game/rom/assets";
+import { GameWorld } from "../src/game/world/world";
+import { generatePartyMon } from "../src/game/party/pokemon";
+import { flypoints, landmarkPosition, regionAtlas } from "../src/game/world/atlas";
+import { defaultTextContext } from "../src/game/scripts/text";
+import { OW } from "../src/game/world/constants";
+
+const romPath =
+  process.env.CRYSTAL_ROM_PATH ??
+  "Pokemon - Crystal Version (UE) (V1.1) [C][!].gbc";
+const pret = ".reference/pokecrystal";
+const NEW_BARK_TOWN = "24:4",
+  LANDMARK_NEW_BARK_TOWN = 1,
+  LANDMARK_ROUTE_29 = 2,
+  LANDMARK_CHERRYGROVE_CITY = 3,
+  LANDMARK_VIOLET_CITY = 6,
+  LANDMARK_AZALEA_TOWN = 12,
+  LANDMARK_PALLET_TOWN = 47;
+
+describe.skipIf(!existsSync(romPath) || !existsSync(`${pret}/data/maps/landmarks.asm`))(
+  "the atlas data against the pinned PRET source",
+  () => {
+    const assets = new CrystalAssets(new Uint8Array(readFileSync(romPath)));
+    const read = (path: string) => readFileSync(`${pret}/${path}`, "utf8");
+    // const_def counts from 0, or from the value given.
+    const constants = (path: string, prefix: string) => {
+      const values = new Map<string, number>();
+      let next = 0;
+      for (const [, start, name] of read(path).matchAll(/^\s+(?:const_def(?: (\d+))?|const (\w+))/gm)) {
+        if (name === undefined) next = Number(start ?? 0);
+        else values.set(name, next++);
+      }
+      return new Map([...values].filter(([name]) => name.startsWith(prefix)));
+    };
+
+    it("places every landmark where data/maps/landmarks.asm does", () => {
+      const rows = [...read("data/maps/landmarks.asm").matchAll(/^\s+landmark\s+(-?\d+),\s*(-?\d+),/gm)];
+      expect(rows).toHaveLength(OW.LANDMARK_FAST_SHIP + 1);
+      rows.forEach(([, x, y], landmark) =>
+        expect(landmarkPosition(assets.reader, landmark), String(landmark)).toEqual({
+          x: Number(x),
+          y: Number(y),
+        }),
+      );
+    });
+
+    it("reads the flypoints of data/maps/flypoints.asm", () => {
+      const landmarks = constants("constants/landmark_constants.asm", "LANDMARK_");
+      const spawns = constants("constants/map_data_constants.asm", "SPAWN_");
+      const rows = [...read("data/maps/flypoints.asm").matchAll(/^\s+db (LANDMARK_\w+),\s*(SPAWN_\w+)/gm)].map(
+        ([, landmark, spawn]) => ({ landmark: landmarks.get(landmark), spawn: spawns.get(spawn) }),
+      );
+      expect(rows).toHaveLength(OW.NUM_FLYPOINTS);
+      expect(flypoints(assets.reader)).toEqual(rows);
+    });
+  },
+);
+
+describe.skipIf(!existsSync(romPath))("the region atlas", () => {
+  const assets = new CrystalAssets(new Uint8Array(readFileSync(romPath)));
+  function fixture(visited: number[]) {
+    const world = new GameWorld(assets, () => new Date("2026-09-25T12:00:00"), () => 0x42);
+    world.state.party = [
+      generatePartyMon(assets.pokemon, {
+        species: 155, level: 8, item: 0, otId: world.playerId,
+        ot: "GOLD", dvs: 0x9abc, caughtData: 0,
+      }),
+    ];
+    world.restore({ ...world.save(), map: NEW_BARK_TOWN, x: 13, y: 7, direction: "down", objects: [] });
+    for (const spawn of visited) world.state.flags.add(assets.spawnEngineFlag(spawn)!);
+    return world;
+  }
+  const spawnOf = (landmark: number) =>
+    flypoints(assets.reader).find((point) => point.landmark === landmark)!.spawn;
+
+  it("shows Johto with the player, the visited flypoints and the open areas", () => {
+    const world = fixture([spawnOf(LANDMARK_NEW_BARK_TOWN), spawnOf(LANDMARK_CHERRYGROVE_CITY)]);
+    const atlas = world.atlas();
+    expect(atlas).toMatchObject({ region: "johto", regions: ["johto"], player: LANDMARK_NEW_BARK_TOWN });
+    expect(atlas.landmarks.map((landmark) => landmark.landmark)).toEqual(
+      Array.from({ length: OW.JOHTO_LANDMARK_LAST }, (_, i) => i + 1),
+    );
+    const at = (landmark: number) => atlas.landmarks[landmark - 1];
+    expect(at(LANDMARK_NEW_BARK_TOWN)).toMatchObject({
+      name: "NEW BARK TOWN",
+      open: true,
+      flypoint: { visited: true },
+    });
+    expect(at(LANDMARK_CHERRYGROVE_CITY).flypoint?.visited).toBe(true);
+    expect(at(LANDMARK_VIOLET_CITY)).toMatchObject({ open: true, flypoint: { visited: false } });
+    expect(at(LANDMARK_ROUTE_29)).toMatchObject({ open: true });
+    expect(at(LANDMARK_ROUTE_29).flypoint).toBeUndefined();
+    expect(at(LANDMARK_AZALEA_TOWN)).toMatchObject({ open: false, flypoint: { visited: false } });
+    // Kanto stays closed, so asking for it shows Johto.
+    expect(world.atlas("kanto").region).toBe("johto");
+  });
+
+  it("opens Kanto once Indigo Plateau is visited, without the player", () => {
+    const world = fixture([OW.SPAWN_INDIGO]);
+    expect(world.atlas().regions).toEqual(["johto", "kanto"]);
+    const kanto = world.atlas("kanto");
+    expect(kanto.region).toBe("kanto");
+    expect(kanto.player).toBeUndefined();
+    expect(kanto.landmarks[0]).toMatchObject({ landmark: LANDMARK_PALLET_TOWN, open: false });
+    expect(kanto.landmarks).toHaveLength(OW.KANTO_LANDMARK_LAST - OW.KANTO_LANDMARK + 1);
+  });
+
+  it("starts on Kanto when the player stands there", () => {
+    const atlas = regionAtlas({
+      reader: assets.reader,
+      text: () => defaultTextContext("GOLD"),
+      landmark: LANDMARK_PALLET_TOWN,
+      visited: () => false,
+      open: new Set(),
+    });
+    expect(atlas).toMatchObject({ region: "kanto", regions: ["johto", "kanto"], player: LANDMARK_PALLET_TOWN });
+  });
+
+  it("leaves the Fast Ship's landmark outside both regions", () => {
+    const ship = regionAtlas({
+      reader: assets.reader,
+      text: () => defaultTextContext("GOLD"),
+      landmark: OW.LANDMARK_FAST_SHIP,
+      visited: () => false,
+      open: new Set(),
+    });
+    expect(ship.region).toBe("johto");
+    expect(ship.player).toBeUndefined();
+  });
+});