Vampire Survivors

Bot API reference

Define _gameUpdate(dt). The editor calls it every animation frame (multiple times per frame at higher speeds).

_getGameState()

player

{ x, y, hp, maxHp } in world pixels, or null before a run starts

enemies

[{ x, y, hp }] in the same world coordinates

xp

Experience toward the next level

level

Current player level

time

Elapsed run time in seconds

gameOver

true on death, victory or when no run is active

canvasW, canvasH

Viewport size (1920×1080). The world is unbounded and the camera stays centered on the player.

_sendAction({ type: "move", dx, dy })

Pass a normalized direction vector (length 1, or 0 to stop). Each axis component beyond ±0.3 presses that direction, so movement snaps to 8 directions at the player's normal speed. The input is held until the next action, and other action types are ignored.

dt

Milliseconds since the previous tick (about 16 at 60fps, divided by the speed multiplier). Accumulate it and compare against 1000 to act once per second. Note that time in the state is in seconds.

Kiting example

let retarget = 0, dir = { dx: 0, dy: 0 };
function _gameUpdate(dt) {
  const s = _getGameState();
  if (s.gameOver || !s.player) return;
  retarget += dt;              // dt is in ms
  if (retarget >= 1000) {      // re-plan once per second
    retarget = 0;
    let fx = 0, fy = 0;        // sum of repulsion from nearby enemies
    for (const e of s.enemies) {
      const ex = s.player.x - e.x, ey = s.player.y - e.y;
      const d = Math.hypot(ex, ey) || 1;
      if (d < 300) { fx += ex / (d * d); fy += ey / (d * d); }
    }
    const len = Math.hypot(fx, fy);
    // Strafe perpendicular to the threat so you circle instead of flee
    dir = len ? { dx: -fy / len, dy: fx / len } : { dx: 0, dy: 0 };
  }
  _sendAction({ type: "move", ...dir });
}