GPS et dessinez avec des turtles

-- Episode : //www.youtube.com/watch?v=xI1Ov35cILU
-- Explication : //www.youtube.com/watch?v=x5N5_0L0wI0

if os.getComputerLabel()==nil then
    os.setComputerLabel("Noel "..os.getComputerID())
    print("set up nom")
end
if fs.exists("config") then
    print("charge config")
    file=fs.open("config","r")
    config= textutils.unserialize(file.readAll())
    file.close()
    print(textutils.serialize(config))
else
    print("creation config")
    local x, y, z = gps.locate(5)
    config={
        x=math.floor(x),
        y=math.floor(y),
        z=math.floor(z)
    }
    file=fs.open("config","w")
    file.write(textutils.serialize(config))
    file.close()
end

local compass=peripheral.find("compass")



print("Attente carburant")
local event, p1 = os.pullEvent("turtle_inventory")
turtle.refuel(1)
print("ok")

local modem=peripheral.find("modem")
modem.open(4242)
event, side, frequency, replyFrequency, message, distance = os.pullEvent("modem_message")

while true do
    local x, y, z = gps.locate(5)
    x=math.floor(x)
    z=math.floor(z)
    y=math.floor(y)
    direction=compass.getFacing()
    if config.x==x and config.y==y and config.z==z then return end
    if config.y~=y then
        if config.y>y then
            turtle.up()
        else
            turtle.down()
        end
    elseif config.x~=x then
        print(direction)
        if direction=='north' then -- z --
            if config.x>x then
                turtle.turnRight()
            else
                turtle.turnLeft()
            end
        elseif direction=='east' then -- x ++
            if config.x>x then
                turtle.forward()
            else
                turtle.turnRight()
                turtle.turnRight()
            end
        elseif direction=='south' then -- z ++
            if config.x>x then
                turtle.turnLeft()
            else
                turtle.turnRight()
            end
        else -- x --
            if config.x>x then
                turtle.turnRight()
                turtle.turnRight()
            else
                turtle.forward()
            end
        end
    else
        print(direction)
        if direction=='north' then -- z --
            if config.z<z then
                turtle.forward()
            else
                turtle.turnRight()
                turtle.turnRight()
            end
        elseif direction=='east' then -- x ++
            if config.z>z then
                turtle.turnRight()
            else
                turtle.turnLeft()
            end
        elseif direction=='south' then -- z ++
            if config.z<z then
                turtle.turnRight()
                turtle.turnRight()
            else
                turtle.forward()
            end
        else -- x --
            if config.z>z then
                turtle.turnLeft()
            else
                turtle.turnRight()
            end
        end
    end
end