-- Simple drone program demonstrating the use of waypoints (added in 1.5.9) on

-- the example of a simple sorting system, pulling items from multiple input

-- inventories and placing the items into multiple output inventories, with

-- optional filtering, based on the waypoint labels.

-- The only config option: how far a waypoint may be away from the starting

-- position for it to be used.

local range = 32

local function proxyFor(name, required)

local address = component and component.list(name)()

if not address and required then

error("missing component '" .. name .. "'")

end

return address and component.proxy(address) or nil

end

local drone = proxyFor("drone", true)

local nav = proxyFor("navigation", true)

local invctrl = proxyFor("inventory_controller")

-- Colors used to indicate different states of operation.

local colorCharing = 0xFFCC33

local colorSearching = 0x66CC66

local colorDelivering = 0x6699FF

-- Keep track of our own position, relative to our starting position.

local px, py, pz = 0, 0, 0

local function moveTo(x, y, z)

if type(x) == "table" then

x, y, z = x[1], x[2], x[3]

end

local rx, ry, rz = x - px, y - py, z - pz

drone.move(rx, ry, rz)

while drone.getOffset() > 0.5 or drone.getVelocity() > 0.5 do

computer.pullSignal(0.5)

end

px, py, pz = x, y, z

end

local function recharge()

drone.setLightColor(colorCharing)

moveTo(0, 0, 0)

if computer.energy() < computer.maxEnergy() * 0.1 then

while computer.energy() < computer.maxEnergy() * 0.9 do

computer.pullSignal(1)

end

end

drone.setLightColor(colorSearching)

end

local function cargoSize()

local result = 0

for slot = 1, drone.inventorySize() do

result = result + drone.count(slot)

end

return result

end

local function pullItems()

-- Only wait up to 5 seconds, avoids dribbling inputs from stalling us.

local start = computer.uptime()

repeat until not drone.suck(0) or computer.uptime() - start > 5

end

local function matchCargo(slot, filter)

if not invctrl or not filter or filter == "" then

return true

end

local stack = invctrl.getStackInInternalSlot(slot)

return stack and stack.name:match(filter)

end

local function haveCargoFor(filter)

for slot = 1, drone.inventorySize() do

if matchCargo(slot, filter) then

return true

end

end

end

local function dropItems(filter)

for slot = 1, drone.inventorySize() do

if matchCargo(slot, filter) then

drone.select(slot)

drone.drop(0)

end

end

end

-- List of known waypoints and their positions relative to the position of the

-- drone when it was started. Waypoints are detected when the program first

-- starts, and when it returns to its home position.

local waypoints

local function updateWaypoints()

waypoints = nav.findWaypoints(range)

end

local function filterWaypoints(filter)

local result = {}

for _, w in ipairs(waypoints) do

if filter(w) then

table.insert(result, w)

end

end

return result

end

-- Main program loop; keep returning to recharge, then check all inputs

-- sequentially, distributing what can be picked up from them to all

-- outputs.

while true do

recharge()

updateWaypoints()

-- Get waypoints marking input inventories; defined as those with a high

-- redstone signal going into them (because there'll usually be more input

-- than output inventories).

local inputs = filterWaypoints(function(w) return w.redstone > 0 end)

local outputs = filterWaypoints(function(w) return w.redstone < 1 end)

for _, input in ipairs(inputs) do

moveTo(input.position)

pullItems()

drone.setLightColor(colorDelivering)

for _, output in ipairs(outputs) do

if cargoSize() == 0 then break end

if haveCargoFor(output.label) then

moveTo(output.position)

dropItems(output.label)

end

end

drone.setLightColor(colorSearching)

end

end