Huge update (again)

api.lua

@@ -1,128 +1,78 @@
-local FUEL_EFFICIENCY = 3	-- How many moves can the turtle do with a second of fuel
+local MOVE_COST = 100
-
+local FUEL_EFFICIENCY = 300
 tl = {}
-local function getv(dir)
-	if dir==0 then return {x=0,y=0,z=1}
-	elseif dir==1 then return {x=1,y=0,z=0}
-	elseif dir==2 then return {x=0,y=0,z=-1}
-	elseif dir==3 then return {x=-1,y=0,z=0} end
-end
 
-local function turtle_can_go(nname)
+local function tl_move(turtle, cptr, dir)
-	return nname == "air" or minetest.registered_nodes[nname].liquidtype ~= "none"
+	local info = turtles.get_turtle_info(turtle)
+	if info.energy < MOVE_COST then
+		cptr.X = 0
+		return
+	end
+	local spos = info.spos
+	local npos = vector.add(spos, dir)
+	if minetest.get_node(npos).name == "air" then
+		minetest.set_node(npos, {name = "turtle:turtle2"})
+		info.npos = npos
+		info.moving = true
+		info.energy = info.energy - MOVE_COST
+		cptr.X = u16(-1)
+		cptr.paused = true
+	else
+		cptr.X = 0
+	end
 end
 
 function tl.forward(turtle, cptr)
-	local info = get_turtle_info(turtle)
+	local dir = turtles.get_turtle_info(turtle).dir
-	if info.fuel == 0 then
+	tl_move(turtle, cptr, minetest.facedir_to_dir(dir))
-		cptr.X = 0
-		return
-	end
-	local spos = info.spos
-	local dir = info.dir
-	local npos = vector.add(spos, getv(dir))
-	if turtle_can_go(minetest.get_node(npos).name) then
-		info.npos = npos
-		info.moving = true
-		info.fuel = info.fuel - 1
-		cptr.X = u16(-1)
-		cptr.paused = true
-	else
-		cptr.X = 0
-	end
 end
 
 function tl.backward(turtle, cptr)
-	local info = get_turtle_info(turtle)
+	local dir = turtles.get_turtle_info(turtle).dir
-	if info.fuel == 0 then
+	tl_move(turtle, cptr, vector.multiply(minetest.facedir_to_dir(dir), -1))
-		cptr.X = 0
-		return
-	end
-	local spos = info.spos
-	local dir = info.dir
-	local npos = vector.add(spos, getv((dir+2)%4))
-	if turtle_can_go(minetest.get_node(npos).name) then
-		info.npos = npos
-		info.moving = true
-		info.fuel = info.fuel - 1
-		cptr.X = u16(-1)
-		cptr.paused = true
-	else
-		cptr.X = 0
-	end
 end
 
 function tl.up(turtle, cptr)
-	local info = get_turtle_info(turtle)
+	tl_move(turtle, cptr, {x = 0, y = 1, z = 0})
-	if info.fuel == 0 then
-		cptr.X = 0
-		return
-	end
-	local spos = info.spos
-	local npos = vector.add(spos, {x=0, y=1, z=0})
-	if turtle_can_go(minetest.get_node(npos).name) then
-		info.npos = npos
-		info.moving = true
-		info.fuel = info.fuel - 1
-		cptr.X = u16(-1)
-		cptr.paused = true
-	else
-		cptr.X = 0
-	end
 end
 
 function tl.down(turtle, cptr)
-	local info = get_turtle_info(turtle)
+	tl_move(turtle, cptr, {x = 0, y = -1, z = 0})
-	if info.fuel == 0 then
-		cptr.X = 0
-		return
-	end
-	local spos = info.spos
-	local npos = vector.add(spos, {x=0, y=-1, z=0})
-	if turtle_can_go(minetest.get_node(npos).name) then
-		info.npos = npos
-		info.moving = true
-		info.fuel = info.fuel - 1
-		cptr.X = u16(-1)
-		cptr.paused = true
-	else
-		cptr.X = 0
-	end
 end
 
 function tl.turnleft(turtle, cptr)
-	local info = get_turtle_info(turtle)
+	local info = turtles.get_turtle_info(turtle)
-	info.ndir = (info.dir+3)%4
+	info.ndir = (info.dir + 3) % 4
-	info.rotate = math.pi/2
+	info.rotate = math.pi / 2
 	info.moving = true
 	cptr.paused = true
 end
 
 function tl.turnright(turtle, cptr)
-	local info = get_turtle_info(turtle)
+	local info = turtles.get_turtle_info(turtle)
-	info.ndir = (info.dir+1)%4
+	info.ndir = (info.dir + 1) % 4
-	info.rotate = -math.pi/2
+	info.rotate = - math.pi / 2
 	info.moving = true
 	cptr.paused = true
 end
 
 local function write_string_at(cptr, addr, str)
-	for i=1, string.len(str) do
+	for i = 1, string.len(str) do
-		cptr[u16(addr-1+i)] = string.byte(str, i)
+		cptr[u16(addr - 1 + i)] = string.byte(str, i)
 	end
 	cptr.X = string.len(str)
 end
 
 local function turtle_detect(turtle, cptr, dir)
-	local info = get_turtle_info(turtle)
+	local info = turtles.get_turtle_info(turtle)
 	local pos = vector.add(info.spos, dir)
 	local name = minetest.get_node(pos).name
 	write_string_at(cptr, cptr.X, name)
 end
 
 function tl.detect(turtle, cptr)
-	local info = get_turtle_info(turtle)
+	local info = turtles.get_turtle_info(turtle)
-	turtle_detect(turtle, cptr, getv(info.dir))
+	turtle_detect(turtle, cptr, minetest.facedir_to_dir(info.dir))
 end
 
 function tl.detectup(turtle, cptr)
@@ -134,27 +84,12 @@ function tl.detectdown(turtle, cptr)
 end
 
 local function turtle_dig(turtle, cptr, dir)
-	local info = get_turtle_info(turtle)
+	-- TODO
-	local dpos = vector.add(info.spos, dir)
-	local dnode = minetest.get_node(dpos)
-	if turtle_can_go(dnode.name) or dnode.name == "ignore" then
-		cptr.X = 0
-		return
-	end
-	local drops = minetest.get_node_drops(dnode.name, "default:pick_mese")
-	local _, dropped_item
-	for _, dropped_item in ipairs(drops) do
-		local leftover = turtle_invs:add_item(turtle,dropped_item)
-		minetest.add_item(info.spos,leftover)
-	end
-	minetest.remove_node(dpos)
-	cptr.X = u16(-1)
-	cptr.paused = true
 end
 
 function tl.dig(turtle, cptr)
-	local info = get_turtle_info(turtle)
+	local info = turtles.get_turtle_info(turtle)
-	turtle_dig(turtle, cptr, getv(info.dir))
+	turtle_dig(turtle, cptr, minetest.facedir_to_dir(info.dir))
 end
 
 function tl.digup(turtle, cptr)
@@ -166,28 +101,12 @@ function tl.digdown(turtle, cptr)
 end
 
 local function turtle_place(turtle, cptr, dir, slot)
-	local info = get_turtle_info(turtle)
+	-- TODO
-	local ppos = vector.add(info.spos, dir)
-	local dnode = minetest.get_node(ppos)
-	if (not turtle_can_go(dnode.name)) or dnode.name == "ignore" then
-		cptr.X = 0
-		return
-	end
-	local stack = turtle_invs:get_stack(turtle, slot)
-	if stack:is_empty() or minetest.registered_nodes[stack:get_name()] == nil then
-		cptr.X = 0
-		return
-	end
-	minetest.set_node(ppos, {name=stack:get_name()})
-	stack:take_item()
-	turtle_invs:set_stack(turtle, slot, stack)
-	cptr.X = u16(-1)
-	cptr.paused = true
 end
 
 function tl.place(turtle, cptr, slot)
-	local info = get_turtle_info(turtle)
+	local info = turtles.get_turtle_info(turtle)
-	turtle_place(turtle, cptr, getv(info.dir), slot)
+	turtle_place(turtle, cptr, minetest.facedir_to_dir(info.dir), slot)
 end
 
 function tl.placeup(turtle, cptr, slot)
@@ -200,13 +119,16 @@ end
 
 local function stack_set_count(stack, count)
 	stack = stack:to_table()
-	if stack==nil then return nil end
+	if stack == nil then return nil end
-	stack.count=count
+	stack.count = count
 	return ItemStack(stack)
 end
 
 function tl.refuel(turtle, cptr, slot, nmax)
-	local info = get_turtle_info(turtle)
+	-- TODO: update that
+	local info = turtles.get_turtle_info(turtle)
+	info.energy = info.energy + 100 * MOVE_COST
+	--[[local info = get_turtle_info(turtle)
 	local stack = turtle_invs:get_stack(turtle, slot)
 	local fuel, afterfuel = minetest.get_craft_result({method = "fuel", width = 1, items = {stack}})
 	if fuel.time <= 0 then
@@ -235,5 +157,5 @@ function tl.refuel(turtle, cptr, slot, nmax)
 		turtle_invs:set_stack(turtle, slot, stack)
 	end
 	info.fuel = info.fuel+FUEL_EFFICIENCY*count*fuel.time
-	cptr.X = u16(FUEL_EFFICIENCY*count*fuel.time)
+	cptr.X = u16(FUEL_EFFICIENCY*count*fuel.time)]]
 end

computer_memory.lua

@@ -1,6 +1,6 @@
 function create_cptr_memory()
-	tbl = {}
+	local tbl = {}
-	for i=0, 65535 do tbl[i] = 0 end
+	for i = 0, 65535 do tbl[i] = 0 end
 	tbl[0xff00] = 0x4d
 	tbl[0xff01] = 0x2a
 	tbl[0xff02] = 0xff

cptr.lua

@@ -10,8 +10,8 @@ local function file_exists(name)
 	return false
 end
 
-function loadpkg(na)
+local function loadpkg(na)
-	local modpath = minetest.get_modpath("forth_computer")
+	local modpath = minetest.get_modpath("turtle")
 	local ol = package.cpath
 	local sp
 	if file_exists(modpath.."/INIT.LUA") then
@@ -21,7 +21,7 @@ function loadpkg(na)
 	else
 		sp = {modpath.."/?.so.32", modpath.."/?.so.64"}
 	end
-	for i=1,#sp do
+	for i=1, #sp do
 		package.cpath = sp[i]
 		e, lib = pcall(require, na)
 		package.cpath = ol
@@ -157,13 +157,13 @@ dofile(modpath.."/api.lua")
 
 function run_computer(turtle, cptr)
 	if cptr.stopped then return end
-	cptr.cycles = math.max(MAX_CYCLES,cptr.cycles+CYCLES_PER_STEP)
+	cptr.cycles = math.max(MAX_CYCLES, cptr.cycles + CYCLES_PER_STEP)
-	while 1 do
+	while true do
 		instr = cptr[cptr.PC]
 		local f = ITABLE[instr]
 		if f == nil then return end
-		cptr.PC = bit32.band(cptr.PC+1, 0xffff)
+		cptr.PC = u16(cptr.PC + 1)
-		setfenv(f, {cptr = cptr, turtle=turtle, receive=receive, delete_message=delete_message, set_channel=set_channel, send_message=send_message, u16=u16, u32=u32, s16=s16, s32=s32, read=read, write=write, readC=readC, writeC=writeC, push=push, pop=pop, rpush=rpush, rpop=rpop, bit32=bit32, math=math, tl=tl})
+		setfenv(f, {cptr = cptr, turtle = turtle, receive = receive, delete_message = delete_message, set_channel = set_channel, send_message = send_message, u16 = u16, u32 = u32, s16 = s16, s32 = s32, read = read, write = write, readC = readC, writeC = writeC, push = push, pop = pop, rpush = rpush, rpop = rpop, bit32 = bit32, math = math, tl = tl})
 		f()
 		cptr.cycles = cptr.cycles - 1
 		if cptr.paused or cptr.cycles <= 0 then
@@ -315,7 +315,7 @@ for i, v in pairs(ITABLE_RAW) do
 end
 
 function on_computer_digiline_receive(turtle, channel, msg)
-	local info = get_turtle_info(turtle)
+	local info = turtles.get_turtle_info(turtle)
 	local cptr = info.cptr
 	cptr.digiline_events[channel] = msg
 end

db.lua

@@ -0,0 +1,21 @@
+db = {}
+
+local worldpath = minetest.get_worldpath() .. "/"
+function db.read_file(filename)
+	local file = io.open(worldpath .. filename, "r")
+	if file == nil then
+		return {}
+	end
+	local contents = file:read("*all")
+	file:close()
+	if contents == "" or contents == nil then
+		return {}
+	end
+	return minetest.deserialize(contents)
+end
+
+function db.write_file(filename, data)
+	local file = io.open(worldpath .. filename, "w")
+	file:write(minetest.serialize(data))
+	file:close()
+end

forth.fth

@@ -165,7 +165,6 @@ FORTH
 : HEX 16 BASE ! ;
 : DECIMAL 10 BASE ! ;
 : TUCK SWAP OVER ;
-: NIP SWAP DROP ;
 : ABS DUP 0< IF NEGATE THEN ;
 : (marker) LATEST ! (here) ! ;
 : TYPE DUP 0> IF OVER + SWAP ?DO I C@ EMIT LOOP ELSE 2DROP THEN ;

init.lua

@@ -1,6 +1,10 @@
+turtles = {}
+
 local modpath = minetest.get_modpath("turtle")
 --dofile(modpath.."/turtle.lua")
-dofile(modpath.."/computer_memory.lua")
+dofile(modpath .. "/db.lua")
-dofile(modpath.."/forth_floppy.lua")
+dofile(modpath .. "/computer_memory.lua")
-dofile(modpath.."/cptr.lua")
+dofile(modpath .. "/forth_floppy.lua")
-dofile(modpath.."/t.lua")
+dofile(modpath .. "/cptr.lua")
+dofile(modpath .. "/screen.lua")
+dofile(modpath .. "/t2.lua")

screen.lua

@@ -0,0 +1,60 @@
+screen = {}
+
+local MAX_LINE_LENGTH = 28
+local function lines(str)
+	local t = {}
+	local function helper(line) table.insert(t, line) return "" end
+	helper((str:gsub("(.-)\r?\n", helper)))
+	return t
+end
+
+local function newline(text, toadd)
+	local f = lines(text)
+	table.insert(f, toadd)
+	return table.concat(f, "\n", 2)
+end
+
+local function add_char(text, char)
+	local ls = lines(text)
+	local ll = ls[#ls]
+	if char == "\n" or char == "\r" then
+		return newline(text, "")
+	elseif string.len(ll) >= MAX_LINE_LENGTH then
+		return newline(text, char)
+	else
+		return text .. char
+	end
+end
+
+local function escape(text)
+	-- Remove all \0's in the string, that cannot be done using string.gsub as there can't be \0's in a pattern
+	text2 = ""
+	for i=1, string.len(text) do
+		if string.byte(text, i) ~= 0 then text2 = text2 .. string.sub(text, i, i) end
+	end
+	return minetest.formspec_escape(text2)
+end
+
+function screen.new()
+	return "\n\n\n\n\n\n\n\n\n\n"
+end
+
+function screen.add_text(text, toadd)
+	for i = 1, string.len(toadd) do
+		text = add_char(text, string.sub(toadd, i, i))
+	end
+	return text
+end
+
+function screen.create_text_formspec(text, basex, basey)
+	local f = lines(text)
+	s = ""
+	i = basey - 0.25
+	for _,x in ipairs(f) do
+		s = s .. "]label[" .. basex .. "," .. tostring(i) .. ";" .. escape(x)
+		i = i + 0.3
+	end
+	s = s .. "]field[" .. tostring(basex + 0.3) .. "," .. tostring(i + 0.4) .. ";4.4,1;f;;]"
+	return s:sub(2, -1)
+end
+

t2.lua

@@ -0,0 +1,347 @@
+local DEBUG = true
+
+-------------------------
+-- Read data from file --
+-------------------------
+
+local turtle_infos = db.read_file("turtle_infos")
+local floppies = db.read_file("floppies")
+
+minetest.register_on_shutdown(function()
+	for id, info in pairs(turtle_infos) do
+		info.turtle = nil
+		info.playernames = {}
+	end
+	db.write_file("turtle_infos", turtle_infos)
+	db.write_file("floppies", floppies)
+end)
+
+function turtles.get_turtle_info(turtle_id)
+	if turtle_infos[turtle_id] == nil then
+		turtle_infos[turtle_id] = {}
+	end
+	return turtle_infos[turtle_id]
+end
+
+function turtles.get_turtle_inventory(turtle_id)
+	local info = turtles.get_turtle_info(turtle_id)
+	return minetest.get_meta(info.spos):get_inventory()
+end
+
+function turtles.create_turtle_id()
+	return #turtle_infos + 1
+end
+
+function turtles.create_floppy_id()
+	return #floppies + 1
+end
+
+function turtles.update_formspec(turtle_id)
+	local info = turtles.get_turtle_info(turtle_id)
+	local pos = info.spos
+	local formspec = "size[9,10]"..
+		screen.create_text_formspec(info.screen, 0, 0)..
+		"list[nodemeta:"..pos.x..","..pos.y..","..pos.z..";main;4.8,0;4,4;]"..
+		"image_button[1,4.6;2.5,1;turtle_execute.png;reboot;]"..
+		"list[nodemeta:"..pos.x..","..pos.y..","..pos.z..";floppy;0,4.6;1,1;]"..
+		"list[current_player;main;0.5,6;8,4;]"
+	if info.formspec ~= formspec then
+		info.formspec = formspec
+		info.formspec_changed = true
+	end
+end
+
+local function on_screen_digiline_receive(turtle, channel, msg)
+	if channel == "screen" then
+		local info = turtles.get_turtle_info(turtle)
+		info.screen = screen.add_text(info.screen, msg)
+		turtles.update_formspec(turtle)
+	end
+end
+
+local function handle_floppy_meta(stack)
+	if stack.metadata == "" or stack.metadata == nil then
+		local id = turtles.create_floppy_id()
+		stack.metadata = tostring(id)
+		floppies[id] = string.rep(string.char(0), 16384)
+		return floppies[id], true
+	elseif string.len(stack.metadata) >= 1000 then
+		local id = turtles.create_floppy_id()
+		floppies[id] = stack.metadata
+		stack.metadata = tostring(id)
+		return floppies[id], true
+	else
+		if floppies[tonumber(stack.metadata)] == nil then
+			floppies[tonumber(stack.metadata)] = string.rep(string.char(0), 16384)
+		end
+		return floppies[tonumber(stack.metadata)], false
+	end
+end
+
+local function set_floppy_contents(name, contents)
+	floppies[tonumber(name)] = contents
+end
+
+function on_disk_digiline_receive(turtle_id, channel, msg)
+	if channel == "boot" then
+		if string.len(msg) ~= 1 and string.len(msg) ~= 65 then return end -- Invalid message, it comes probably from the disk itself
+		local page = string.byte(msg, 1)
+		if page == nil then return end
+		local inv = turtles.get_turtle_inventory(turtle_id)
+		local stack = inv:get_stack("floppy", 1):to_table()
+		if stack == nil then return end
+		if stack.name ~= "turtle:floppy" then return end
+		local floppy_contents, update = handle_floppy_meta(stack)
+		if update then
+			inv:set_stack("floppy", 1, ItemStack(stack))
+		end
+		msg = string.sub(msg, 2, -1)
+		if string.len(msg) == 0 then -- read
+			turtle_receptor_send(turtle_id, channel,
+				string.sub(floppy_contents, page * 64 + 1, page * 64 + 64))
+		else -- write
+			floppy_contents = string.sub(floppy_contents, 1, page * 64) ..
+			                  msg ..
+			                  string.sub(floppy_contents, page * 64 + 65, -1)
+			set_floppy_contents(stack.metadata, floppy_contents)
+		end
+	end
+end
+
+minetest.register_craftitem("turtle:floppy", {
+	description = "Floppy disk",
+	inventory_image = "floppy.png",
+	stack_max = 1,
+})
+
+local progs = {
+	["Empty"] = string.rep(string.char(0), 16536),
+	["Forth Boot Disk"] = create_forth_floppy(),
+}
+
+minetest.register_node("turtle:floppy_programmator",{
+	description = "Floppy disk programmator",
+	tiles = {"floppy_programmator_top.png", "floppy_programmator_bottom.png", "floppy_programmator_right.png",
+	         "floppy_programmator_left.png", "floppy_programmator_back.png", "floppy_programmator_front.png"},
+	groups = {cracky = 3},
+	sounds = default.node_sound_stone_defaults(),
+	on_construct = function(pos)
+		local meta = minetest.get_meta(pos)
+		local inv = meta:get_inventory()
+		inv:set_size("floppy", 1)
+		meta:set_int("selected", 1)
+		local s = "size[8,5.5;]" ..
+			  "dropdown[0,0;5;pselector;"
+		for key, _ in pairs(progs) do
+			s = s .. key .. ","
+		end
+		s = string.sub(s, 1, -2)
+		s = s .. ";1]" ..
+		         "button[5,0;2,1;prog;Program]" ..
+		         "list[current_name;floppy;7,0;1,1;]" ..
+		         "list[current_player;main;0,1.5;8,4;]"
+		meta:set_string("formspec", s)
+	end,
+	can_dig = function(pos, player)
+		local meta = minetest.get_meta(pos)
+		local inv = meta:get_inventory()
+		return inv:is_empty("floppy")
+	end,
+	allow_metadata_inventory_put = function(pos, listname, index, stack, player)
+		if stack:get_name() == "turtle:floppy" then return 1 end
+		return 0
+	end,
+	on_receive_fields = function(pos, formname, fields, sender)
+		local meta = minetest.get_meta(pos)
+		if fields.prog then
+			local inv = meta:get_inventory()
+			local prog = progs[fields.pselector]
+			local stack = inv:get_stack("floppy", 1):to_table()
+			if stack == nil then return end
+			if stack.name ~= "turtle:floppy" then return end
+			local contents, update = handle_floppy_meta(stack)
+			set_floppy_contents(stack.metadata, prog)
+			if update then
+				inv:set_stack("floppy", 1, ItemStack(stack))
+			end
+		end
+	end,
+})
+
+function turtle_receptor_send(turtle, channel, msg)
+	on_screen_digiline_receive(turtle, channel, msg)
+	on_computer_digiline_receive(turtle, channel, msg)
+	on_disk_digiline_receive(turtle, channel, msg)
+	--on_turtle_command_receive(turtle, channel, msg)
+end
+
+minetest.register_on_player_receive_fields(function(player, formname, fields)
+	if formname:sub(1, 7) ~= "turtle:" then return end
+	local turtle_id = tonumber(formname:sub(8, -1))
+	if fields.f ~= nil and fields.f ~= "" then
+		if string.len(fields.f) > 80 then
+			fields.f = string.sub(fields.f, 1, 80)
+		end
+		turtle_receptor_send(turtle_id, "screen", fields.f)
+		turtles.update_formspec(turtle_id)
+		return
+	end
+	if fields.reboot then
+		local info = turtles.get_turtle_info(turtle_id)
+		info.cptr = create_cptr()
+		return
+	end
+	if fields.quit then
+		local info = turtles.get_turtle_info(turtle_id)
+		info.playernames[player:get_player_name()] = nil
+	end
+end)
+
+minetest.register_node("turtle:turtle", {
+	description = "Turtle",
+	drawtype = "airlike",
+	inventory_image = "turtle_turtle_inv.png",
+	sunlight_propagates = true,
+	walkable = false,
+	pointable = false,
+	after_place_node = function(pos)
+		local meta = minetest.get_meta(pos)
+		local inv = meta:get_inventory()
+		inv:set_size("floppy", 1)
+		inv:set_size("main", 8 * 4)
+		inv:set_size("craft", 3 * 3)
+		inv:set_size("craft_output", 1)
+		local id = turtles.create_turtle_id()
+		meta:set_int("turtle_id", id)
+		local info = turtles.get_turtle_info(id)
+		info.spos = vector.new(pos)
+		info.dir = 0
+		info.energy = 0
+		info.screen = screen.new()
+		info.cptr = create_cptr()
+		info.playernames = {}
+		turtles.update_formspec(id)
+		local le = minetest.add_entity(pos, "turtle:turtle"):get_luaentity()
+		info.turtle = le
+		le.turtle_id = id
+	end,
+})
+
+minetest.register_node("turtle:turtle2", {
+	description = "turtle:turtle2 (You hacker you)",
+	groups = {not_in_creative_inventory = 1},
+	drawtype = "airlike",
+	walkable = false,
+	pointable = false,
+})
+
+local function done_move(pos, spos, npos)
+	return vector.dot(vector.subtract(npos, spos),
+	                  vector.subtract(npos, pos)) <= 0
+end
+
+local function done_rotation(yaw, nyaw, rotate_speed)
+	return (nyaw - yaw + rotate_speed - math.pi / 2) % (2 * math.pi) < math.pi
+end
+
+minetest.register_entity("turtle:turtle", {
+	physical = true,
+	collisionbox = {-0.5, -0.5, -0.5, 0.5, 0.5, 0.5},
+	collides_with_objects = false,
+	visual = "wielditem", -- TODO: change that to a mesh, and add animations
+	visual_size = {x = 2/3, y = 2/3},
+	textures = {"default:wood"},
+	on_activate = function(self, staticdata)
+		local id = tonumber(staticdata)
+		if id ~= nil then
+			self.turtle_id = id
+			if turtle_infos[self.turtle_id] == nil then
+				minetest.set_node(vector.round(self.object:getpos()), {name = "air"})
+				self.object:remove()
+				return
+			end
+			local info = turtles.get_turtle_info(self.turtle_id)
+			info.turtle = self
+		end
+	end,
+	on_step = function(self, dtime)
+		if self.turtle_id == nil then return end
+		local info = turtles.get_turtle_info(self.turtle_id)
+		if info.rotate then
+			self.object:setyaw(self.object:getyaw() + info.rotate * dtime)
+		end
+		if info.moving then
+			if info.npos ~= nil then
+				local pos = self.object:getpos()
+				local npos = info.npos
+				local spos = info.spos
+				if done_move(pos, spos, npos) then
+					self.object:setpos(npos)
+					self.object:setvelocity({x = 0, y = 0, z = 0})
+					info.spos = npos
+					info.npos = nil
+					info.moving = nil
+					local meta = minetest.get_meta(spos):to_table()
+					minetest.set_node(spos, {name = "air"})
+					minetest.set_node(npos, {name = "turtle:turtle"})
+					minetest.get_meta(npos):from_table(meta)
+					turtles.update_formspec(self.turtle_id)
+				else
+					self.object:setvelocity(vector.subtract(npos, spos))
+				end
+			elseif info.ndir ~= nil then
+				local yaw = self.object:getyaw()
+				local rotate_speed = info.rotate
+				local nyaw = info.ndir * math.pi/2
+				if done_rotation(yaw, nyaw, rotate_speed) then
+					self.object:setyaw(nyaw)
+					info.dir = info.ndir
+					info.ndir = nil
+					info.rotate = nil
+					info.moving = nil
+				end
+			end
+		end
+		if not info.moving then
+			run_computer(self.turtle_id, info.cptr)
+		end
+		if info.formspec_changed then
+			for playername, _ in pairs(info.playernames) do
+				if DEBUG then
+					print(info.screen)
+					print("------------------------------------")
+				end
+				minetest.show_formspec(playername, "turtle:" .. tostring(self.turtle_id), info.formspec)
+			end
+			info.formspec_changed = nil
+		end
+	end,
+	on_rightclick = function(self, clicker)
+		local info = turtles.get_turtle_info(self.turtle_id)
+		local name = clicker:get_player_name()
+		info.playernames[name] = true
+		minetest.show_formspec(name, "turtle:" .. tostring(self.turtle_id), info.formspec)
+	end,
+	on_punch = function(self, puncher, time_from_last_punch, tool_capabilities, dir)
+		self.object:remove()
+		local info = turtles.get_turtle_info(self.turtle_id)
+		local pos = info.spos
+		minetest.add_item(pos, "turtle:turtle")
+		local inv = minetest.get_meta(pos):get_inventory()
+		
+		for list, nslots in pairs({["main"] = 8 * 4, ["floppy"] = 1, ["craft"] = 3 * 3}) do
+			for slot = 1, nslots do
+				minetest.add_item(pos, inv:get_stack(list, slot))
+			end
+		end
+		
+		if info.npos then
+			minetest.set_node(info.npos, {name = "air"})
+		end
+		minetest.set_node(pos, {name = "air"})
+		turtle_infos[self.turtle_id] = nil
+	end,
+	get_staticdata = function(self)
+		return tostring(self.turtle_id)
+	end,
+})