typescript-game-boss-arena-encounter

Answer

The boss arena encounter (RR-GAP-016) has four defects — invisible, unreachable, harmless, skippable — fixed by two config changes and two code changes.

1. Visibility + reachability — config-only waypoint band (no logic change)

Camera viewport is y 298..478 (320×180 render). The old waypoint band 200..340 was half off-screen (200–298 above the camera top). The boss weak point is [y+15, y+33]; the player's body at jump apex is [415,447]. Overlap requires y+33 ≥ 415 (y ≥ 382) and y+15 ≤ 447 (y ≤ 432), so the jump-reachable band is [382,432] and the old band produced both an above-apex unreachable zone and the 432..479 dead zone. New band 390..420 sits inside both the camera frustum and the reachable band:

// config/boss.ts
export const BOSS_WAYPOINTS = [
  { x: 20,  y: 390 },   // patrol band: 390..420
  { x: 96,  y: 410 },
  { x: 160, y: 420 },
  { x: 224, y: 410 },
  { x: 300, y: 390 },
] as const;

2. Harmlessness — attachTurret-style damage wiring via BossControllerOptions.damage

The boss controller spawned projectiles that moved but never had their hitboxes checked against the player (unlike attachTurret, which wires exactly this). The options type gains damage (and floorY for drops) and the shot update reuses the turret collision pattern:

export interface BossControllerOptions {
  waypoints: Point[];
  damage: number;   // NEW — boss projectile damage (wired like attachTurret)
  floorY: number;   // NEW — drop floor for loot
  speed?: number;
}

export function createBossController(opts: BossControllerOptions): BossController {
  const shots: Shot[] = [];
  return {
    shots,
    fire(from: Point, dir: Vec) {
      shots.push(createShot({ ...from, vx: dir.x, vy: dir.y, damage: opts.damage }));
    },
    update() {
      // ...existing patrol/move logic unchanged...
      for (const shot of shots) {
        shot.update();
        // attachTurret-style wiring: only now does a hit actually hurt the player
        if (overlaps(shot.hitbox, player.hitbox)) {
          player.takeDamage(shot.damage, { knockback: shot.dir });
          shot.kill();
        }
      }
    },
  };
}

3. Drops — params.floorY = 544

function bossDefeated() {
  session.bossActive = false;
  spawnDrops(boss.position, { n: 3, floorY: 544 }); // items rest on floor 544, collectible
  if (!session.bossActive) sealLevelClear();
}

4. Skippable — flow-level session.bossActive gate

goalReached previously sealed LEVEL_CLEAR unconditionally, so the fight could be skipped. A session-level flag now gates sealing, set on encounter start and cleared on every exit path:

// flow.ts
beginBossEncounter(opts)  { session.bossActive = true;  spawnBoss(opts); }
bossDefeated()            { session.bossActive = false; /* drops, seal */ }
playerDied()              { session.bossActive = false; }
quit()                    { session.bossActive = false; }
enterLevel()              { session.bossActive = false; }

// sealed state transition — mid-fight goalReached is ignored
if (goalReached && !session.bossActive) sealLevelClear();

5. Seven new tests (vitest-style, all pass; suite 712/712):

test('waypoint band is on-screen and jump-reachable', () => {
  BOSS_WAYPOINTS.forEach(w =>
    expect(w.y).toBeGreaterThanOrEqual(298)  // camera top
      .and(w.y).toBeLessThanOrEqual(478)     // camera bottom
      .and(w.y).toBeGreaterThanOrEqual(382)  // reachable band
      .and(w.y).toBeLessThanOrEqual(432));
});
test('weak point [y+15,y+33] overlaps jump-apex body [415,447] for all waypoints', () => {
  BOSS_WAYPOINTS.forEach(w => {
    const weakTop = w.y + 15, weakBot = w.y + 33;
    expect(Math.max(weakTop, 415)).toBeLessThanOrEqual(Math.min(weakBot, 447));
  });
});
test('boss projectile collision applies damage and kills shot (attachTurret wiring)', () => {
  const boss = createBossController({ waypoints: BOSS_WAYPOINTS, damage: 1, floorY: 544 });
  boss.fire(player.position, { x: 0, y: 0 });
  const hp = player.hp;
  boss.update(); // shot overlaps player
  expect(player.hp).toBe(hp - 1);
  expect(boss.shots).toHaveLength(0);
});
test('projectile damage reads BossControllerOptions.damage', () => {
  const boss = createBossController({ waypoints: BOSS_WAYPOINTS, damage: 2, floorY: 544 });
  boss.fire(player.position, { x: 0, y: 0 });
  boss.update();
  expect(player.hp).toBe(hp - 2);
});
test('drops spawn with floorY = 544', () => {
  expect(dropParams.floorY).toBe(544);
});
test('goalReached does not seal LEVEL_CLEAR while session.bossActive', () => {
  session.bossActive = true;
  goalReached = true;
  update();
  expect(gameState).not.toBe('LEVEL_CLEAR');
});
test('bossActive lifecycle: set on begin, cleared on bossDefeated/playerDied/quit/enterLevel', () => {
  beginBossEncounter(...);  expect(session.bossActive).toBe(true);
  bossDefeated();           expect(session.bossActive).toBe(false);
  beginBossEncounter(...);  playerDied(); expect(session.bossActive).toBe(false);
  beginBossEncounter(...);  quit();       expect(session.bossActive).toBe(false);
  beginBossEncounter(...);  enterLevel(); expect(session.bossActive).toBe(false);
});