function update_keyboard()
  --get keys inputs
  --debug key
  if love.keyboard.isDown("d") then debug.debug() end
  --swap selected object
  local buffer = k_tab
  k_tab = love.keyboard.isScancodeDown("tab")
  if k_tab and not buffer then
    if love.keyboard.isDown("lshift") then
      selected_tile = selected_tile - 1
      if selected_tile == 0 then selected_tile = #tiles end
    else selected_tile = selected_tile + 1
      if selected_tile > #tiles then selected_tile = 1 end
    end
  end
  --exit
  if love.keyboard.isScancodeDown("escape") then
    love.event.quit()
  end
  --saving/export
  local buffer = k_s
  k_s = love.keyboard.isDown("s")
  if k_s and not buffer then
  end
  local buffer = k_o
  k_o = love.keyboard.isDown("o")
  if k_o and not buffer then
  end
  --scaling
  local buffer = k_k
  k_k = love.keyboard.isDown("k")
  if k_k and not buffer and scale > 1 then
    scale = scale - 1
    love.window.setMode(GAME_WIDTH * scale, GAME_HEIGHT * scale, flags)
  end
  local buffer = k_l
  k_l = love.keyboard.isDown("l")
  if k_l and not buffer and scale < 8 then
    scale = scale + 1
    love.window.setMode(GAME_WIDTH * scale, GAME_HEIGHT * scale, flags)
  end
end