帮忙SLG寻路代码

虾米￡浪子

def find_next_point(x, y, r)
    return if !@path_hash[[x, y, r]].nil?
    @path << [x, y] if(!@path.include?([x, y]))
    @path_hash[[x, y]] = true
     find_next_point(x - 1,y, r - 1) if r > 0 && @coordinate[x-1,y] == 0
     find_next_point(x + 1,y, r - 1) if r > 0 && @coordinate[x+1,y] == 0
     find_next_point( x,y + 1, r - 1) if r > 0 && @coordinate[x,y+1] == 0
     find_next_point( x,y - 1, r - 1) if r > 0 && @coordinate[x,y-1] == 0
     end   


这个是移动范围,但是寻路计算不出来.求教