Lua 对象不唯一

在尝试创建一个非常简单的类继承时，所有的对象似乎都共享相同的值。

这是我的代码的简化版：

--通用类
Object = {}

function Object:new (type,id,name)
  o = {}
  self.type = type or "none"
  self.id = id or 0
  self.name = name or "noname"
  self.direction = "down"
  self.animations = {}
  self.animations.stack = {}
  self.animations.idle = {}
  self.animations.idle[self.direction] = {}
  setmetatable(o, self)
  self.__index = self
  return o
end

function Object:draw(x,y)
  local img = self.animations.idle["down"][0]
  print("drawing " ..self.name.." as "..img)
end

function Object:setimg(img)
  self.animations.idle["down"][0] = img
end

--玩家类
Player = Object:new()

function Player:new(id,name)
  local o = self

  o.id = id or 0
  o.name = name or "noname"

  o.collision = {}
  o.collision.type = "player"

  return o
end

function Player:move(x,y)
  print("moving to ",x,y)
end

--测试
blockimg = "block.png"
grassimg = "grass.png"
plyrimg = "player.png"

block = Object:new("solid",1,"block")
block:setimg(blockimg)

grass = Object:new("floor",3,"grass")
grass:setimg(grassimg)

player = Player:new(1, "plyr1")
player:setimg(plyrimg)

block:draw() -- >drawing grass as player.png
grass:draw() -- >drawing grass as player.png
player:draw()-- >drawing plyr1 as player.png

由于 player:setimg 是最后调用的，所有的 "对象" 最终都使用了 plyrimg，因此它们不是唯一的。