tile pathfinder

heightmap.rb

def route_to(start_x, start_y, end_x, end_y, path=[], last_routes=[])
  possible_routes = sorted_routes(start_x, start_y, end_x, end_y)
  if r = possible_routes.find {|route| route == [end_x, end_y]}
    return path + [[*r, new_item_height(*r)]]
  else
    possible_routes.each do |(possible_x, possible_y)|
      next if last_routes.include? [possible_x, possible_y]
      new_path = path + [[possible_x, possible_y, new_item_height(possible_x, possible_y)]]
      used_routes = (last_routes + possible_routes).uniq
      new_route = route_to(possible_x, possible_y, end_x, end_y, new_path, used_routes)
      return new_route if new_route
    end
  end
  nil
end

def sorted_routes(start_x, start_y, end_x, end_y)
  neighbors(start_x, start_y).sort_by do |(x, y)|
    (end_x - x).abs + (end_y - y).abs
  end
end

def neighbors(x, y)
  surrounding(x, y).reject do |(x, y)|
    within_grid?(x, y) || blocked?(x, y)
  end
end

def surrounding(x, y)
  [[x - 1, y - 1],
  [x - 1,  y],
  [x - 1, y +1],
  [x, y - 1],
  [x, y + 1],
  [x + 1, y - 1],
  [x + 1, y],
  [x + 1, y + 1]]
end      

def within_grid?(x, y)
  row = heightmap_data[y]
  x < 0 || y < 0 || row.nil? || row[x].nil?
end