module.exports = rotate

/**
 * Rotates a vec2 by an angle
 *
 * @param {vec2} out the receiving vector
 * @param {vec2} a the vector to rotate
 * @param {Number} angle the angle of rotation (in radians)
 * @returns {vec2} out
 */
function rotate(out, a, angle) {
  var c = Math.cos(angle),
      s = Math.sin(angle)
  var x = a[0],
      y = a[1]

  out[0] = x * c - y * s
  out[1] = x * s + y * c

  return out
}