Sébastien QUEROLandClaude Opus 5.5
f259163da9
Facing a Headbutt tree asks to HEADBUTT it, and HEADBUTT from the party menu skips the question. ShakeHeadbuttTree shakes the tree as a sprite over grass, then TreeMonEncounter scores the facing tile against the trainer ID and draws from the map's common or rare tree table. A Pokémon that falls fights as BATTLETYPE_TREE: "fell out of the tree!", and the time of day's AsleepTreeMons species start asleep. Smashable rocks run SmashRockScript, and ROCK SMASH from the party menu acts on the facing rock; after the rock breaks, RockMonEncounter gives the map's rock set a 40% chance of a wild battle. Closes #26 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
98 lines
3.6 KiB
TypeScript
98 lines
3.6 KiB
TypeScript
import type { RomReader } from "../rom/reader";
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import { OVERWORLD } from "../rom/profile";
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import { OW } from "../world/constants";
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/** Headbutt trees and Rock Smash rocks (engine/events/treemons.asm). */
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export interface TreeMon {
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species: number;
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level: number;
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}
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/** TREEMON_SCORE_BAD, _GOOD and _RARE. */
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const SCORE_BAD = 0,
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SCORE_GOOD = 1,
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SCORE_RARE = 2;
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/** TreeMonEncounter: the map's TreeMonMaps set, scored by the facing tile
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* (in wPlayerMapX/Y coordinates, four more than the map's) against the
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* trainer ID, then an encounter roll and SelectTreeMon. Undefined when
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* nothing falls; a Pokémon found fights as BATTLETYPE_TREE. */
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export function treeMonEncounter(
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r: RomReader,
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mapId: string,
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facing: { x: number; y: number },
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playerId: number,
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randomRange: (range: number) => number,
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): TreeMon | undefined {
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let table = treeMons(r, treeMonSet(r, OVERWORLD.TreeMonMaps, mapId));
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if (table === undefined) return undefined;
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// GetTreeMon: 10% for a bad score, 50% for a good one, 80% for a rare
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// one, which also skips past the common table to the rare one.
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const score = treeScore(facing.x, facing.y, playerId);
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const draw = randomRange(10);
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if (score === SCORE_BAD && draw !== 0) return undefined;
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if (score === SCORE_GOOD && draw >= 5) return undefined;
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if (score === SCORE_RARE) {
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if (draw >= 8) return undefined;
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while (r.byte(table++) !== 0xff);
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}
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return selectTreeMon(r, table, randomRange);
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}
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/** RockMonEncounter: the map's RockMonMaps set, a 40% chance, then
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* SelectTreeMon. Undefined when the rock hides nothing. */
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export function rockMonEncounter(
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r: RomReader,
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mapId: string,
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randomRange: (range: number) => number,
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): TreeMon | undefined {
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const table = treeMons(r, treeMonSet(r, OVERWORLD.RockMonMaps, mapId));
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if (table === undefined) return undefined;
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if (randomRange(10) >= 4) return undefined;
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return selectTreeMon(r, table, randomRange);
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}
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/** GetTreeScore: .CoordScore is (x × y + x + y) / 5 modulo 10 and
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* .OTIDScore the trainer ID modulo 10; equal scores are rare, and a
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* coordinate score less than five above the ID's (wrapping by ten) good. */
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export function treeScore(x: number, y: number, playerId: number): number {
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const coord = Math.floor(((x * y + x + y) & 0xffff) / 5) % 10;
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let difference = coord - (playerId % 10);
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if (difference === 0) return SCORE_RARE;
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if (difference < 0) difference += 10;
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return difference < 5 ? SCORE_GOOD : SCORE_BAD;
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}
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/** GetTreeMonSet: the TREEMON_SET_* of map `mapId` in TreeMonMaps or
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* RockMonMaps (group, number, set entries ending with -1). */
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function treeMonSet(r: RomReader, table: number, mapId: string) {
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const [group, number] = mapId.split(":").map(Number);
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for (let p = table; r.byte(p) !== 0xff; p += 3)
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if (r.byte(p) === group && r.byte(p + 1) === number) return r.byte(p + 2);
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return undefined;
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}
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/** GetTreeMons: the set's common table in TreeMons; TREEMON_SET_NONE and
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* sets past NUM_TREEMON_SETS have none. */
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function treeMons(r: RomReader, set: number | undefined) {
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if (!set || set >= OW.NUM_TREEMON_SETS) return undefined;
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return r.near(OVERWORLD.TreeMons + set * 2, r.bank(OVERWORLD.TreeMons));
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}
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/** SelectTreeMon: 0-99 against the table's percentages (percent, species,
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* level entries ending with -1). */
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function selectTreeMon(
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r: RomReader,
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table: number,
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randomRange: (range: number) => number,
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): TreeMon | undefined {
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let roll = randomRange(100),
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p = table;
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while (roll >= r.byte(p)) {
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roll -= r.byte(p);
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p += 3;
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}
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if (r.byte(p) === 0xff) return undefined;
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return { species: r.byte(p + 1), level: r.byte(p + 2) };
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}
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