code: private Force computeVector(Force vector)
      {
          if (target != null)
          {
              return computeVector(vector, target);
          }
          vector.setDestination(vector.getDirectionHorizontal(), vector.getDirectionVertical());
          return vector;
      }
docs: Compute the vector used for launch.
  
  @param vector The initial vector used for launch.
  @return The vector used for launch.