function translation(x, y, z, out) {
  out = out ?? create();

  out[0] = 1;
  out[1] = 0;
  out[2] = 0;
  out[3] = 0;
  out[4] = 0;
  out[5] = 1;
  out[6] = 0;
  out[7] = 0;
  out[8] = 0;
  out[9] = 0;
  out[10] = 1;
  out[11] = 0;
  out[12] = x;
  out[13] = y;
  out[14] = z;
  out[15] = 1;

  return out;
}
@param {number} x x translation.
@param {number} y y translation.
@param {number} z z translation.
@param {Mat4} [out] optional matrix to store result
@return {Mat4} out