slower_in_liquid/init.lua

--TODO: maybe some glitches? 

minetest.register_on_joinplayer(function(player)
  local meta = player:get_meta()
  meta:set_float("speed", 1)
end)

minetest.register_globalstep(function(dtime)
for _,player in ipairs(minetest.get_connected_players()) do
  local meta = player:get_meta()
  local name = player:get_player_name()
  if minetest.get_node(player:get_pos()).name == "default:water_source" then
    meta:set_int("in_liquid", 1)
  else
    meta:set_int("in_liquid", 0)
  end

  --print( meta:get_int("in_liquid") )
  local tempmeta = meta:get_int("in_liquid")

  if tempmeta==1 then
    if math.floor(player:get_physics_override().speed*10)/10 ~= 0.4 then
      meta:set_float("speed", player:get_physics_override().speed)
    end
    player:set_physics_override({
            speed = 0.4
        })
  elseif tempmeta==0 then
    if math.floor(player:get_physics_override().speed*10)/10 == 0.4 then
      player:set_physics_override({
              speed = meta:get_float("speed")
          })
    end


  end

end
end)