--
function create_button(btn_num)
 return
 {
   --上次按压后的时间
  time_since_press=100,
  --按键按下去的持续时间
  time_held=0,
  --按钮
  button_number=btn_num,

  button_init=function(b)
   b.time_since_press,b.time_held=100,0
  end,

  button_update=function(b)
   b.time_since_press+=one_frame
    --当按键按下时开始记录按下持续时间和上次按下持续时间
   if btn(b.button_number) then
    if b.time_held==0 then
     b.time_since_press=0
    end

    b.time_held+=one_frame
   else
    b.time_held=0
   end
  end,

  --重新初始化按钮
  button_consume=function(b)
   b.time_since_press=100
  end,
 }
end

--

shoot_button=create_button(4)
dash_button=create_button(5)
shoot_button:button_init()
dash_button:button_init()

--如果按键按下去的时间不足0.2s，则将按钮的time_since_press设为100，即使按钮还没有抬起，依旧不会执行if中的语句，当再次按下按钮的时候time_since_press会被重置为0并触发if语句
if shoot_button.time_since_press<.2 or dash_button.time_since_press<.2 then
  shoot_button:button_consume()
  dash_button:button_consume()
end

--在_update中执行button_update
 shoot_button:button_update()
 dash_button:button_update()