Add bits that are done so far

This includes:
* Controller (runs and responds to calls placed on the screen, parameter editing and switches work)
* Null Drive (simulates motion so the controller can run, no actual movement yet)
* Call Buttons (lights can be toggled with right-click, no communication yet)

.luacheckrc

@@ -0,0 +1,12 @@
+max_line_length = 200
+
+globals = {
+	"celevator",
+}
+
+read_globals = {
+	"DIR_DELIM",
+	"vector",
+	"screwdriver",
+	"minetest",
+}

COPYING

@@ -0,0 +1,22 @@
+This is free and unencumbered software released into the public domain.
+
+Anyone is free to copy, modify, publish, use, compile, sell, or
+distribute this software, either in source code form or as a compiled
+binary, for any purpose, commercial or non-commercial, and by any
+means.
+
+In jurisdictions that recognize copyright laws, the author or authors
+of this software dedicate any and all copyright interest in the
+software to the public domain. We make this dedication for the benefit
+of the public at large and to the detriment of our heirs and
+successors. We intend this dedication to be an overt act of
+relinquishment in perpetuity of all present and future rights to this
+software under copyright law.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
+OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+OTHER DEALINGS IN THE SOFTWARE.

callbuttons.lua

@@ -0,0 +1,152 @@
+local function makebuttontex(dir,upon,downon)
+	local tex = "[combine:64x64:0,0=celevator_cabinet_sides.png:32,0=celevator_cabinet_sides.png:0,32=celevator_cabinet_sides.png:32,32=celevator_cabinet_sides.png:22,24=celevator_callbutton_panel.png"
+	if dir == "up" then
+		tex = tex..":24,35=celevator_callbutton_up.png"
+		if upon then
+			tex = tex..":33,36=celevator_callbutton_light.png"
+		end
+	elseif dir == "down" then
+		tex = tex..":24,35=celevator_callbutton_down.png"
+		if downon then
+			tex = tex..":33,36=celevator_callbutton_light.png"
+		end
+	elseif dir == "both" then
+		tex = tex..":24,28=celevator_callbutton_up.png:24,43=celevator_callbutton_down.png"
+		if upon then
+			tex = tex..":33,29=celevator_callbutton_light.png"
+		end
+		if downon then
+			tex = tex..":33,44=celevator_callbutton_light.png"
+		end
+	end
+	return(tex)
+end
+
+local validstates = {
+	{"up",false,false,"Up"},
+	{"up",true,false,"Up"},
+	{"down",false,false,"Down"},
+	{"down",false,true,"Down"},
+	{"both",false,false,"Up and Down"},
+	{"both",true,false,"Up and Down"},
+	{"both",false,true,"Up and Down"},
+	{"both",true,true,"Up and Down"},
+}
+
+local function setlight(pos,dir,newstate)
+	local node = minetest.get_node(pos)
+	if minetest.get_item_group(node.name,"_celevator_callbutton") ~= 1 then return end
+	if dir == "up" then
+		if minetest.get_item_group(node.name,"_celevator_callbutton_has_up") ~= 1 then return end
+		local lit = minetest.get_item_group(node.name,"_celevator_callbutton_up_lit") == 1
+		if lit == newstate then return end
+		local newname = "celevator:callbutton_"
+		if minetest.get_item_group(node.name,"_celevator_callbutton_has_down") == 1 then
+			newname = newname.."both"
+		else
+			newname = newname.."up"
+		end
+		if newstate then newname = newname.."_upon" end
+		if minetest.get_item_group(node.name,"_celevator_callbutton_down_lit") == 1 then
+			newname = newname.."_downon"
+		end
+		node.name = newname
+		minetest.swap_node(pos,node)
+	elseif dir == "down" then
+		if minetest.get_item_group(node.name,"_celevator_callbutton_has_down") ~= 1 then return end
+		local lit = minetest.get_item_group(node.name,"_celevator_callbutton_down_lit") == 1
+		if lit == newstate then return end
+		local newname = "celevator:callbutton_"
+		if minetest.get_item_group(node.name,"_celevator_callbutton_has_up") == 1 then
+			newname = newname.."both"
+		else
+			newname = newname.."down"
+		end
+		if minetest.get_item_group(node.name,"_celevator_callbutton_up_lit") == 1 then
+			newname = newname.."_upon"
+		end
+		if newstate then newname = newname.."_downon" end
+		node.name = newname
+		minetest.swap_node(pos,node)
+	end
+end
+
+local function disambiguatedir(pos,player)
+	if player and not player.is_fake_player then
+		local eyepos = vector.add(player:get_pos(),vector.add(player:get_eye_offset(),vector.new(0,1.5,0)))
+		local lookdir = player:get_look_dir()
+		local distance = vector.distance(eyepos,pos)
+		local endpos = vector.add(eyepos,vector.multiply(lookdir,distance+1))
+		local ray = minetest.raycast(eyepos,endpos,true,false)
+		local pointed,button,hitpos
+		repeat
+			pointed = ray:next()
+			if pointed and pointed.type == "node" then
+				local node = minetest.get_node(pointed.under)
+				if node.name and (minetest.get_item_group(node.name,"_celevator_callbutton") == 1) then
+					button = pointed.under
+					hitpos = vector.subtract(pointed.intersection_point,button)
+				end
+			end
+		until button or not pointed
+		if not hitpos then return end
+		hitpos.y = -1*hitpos.y
+		hitpos.y = math.floor((hitpos.y+0.5)*64+0.5)+1
+		return hitpos.y >= 40 and "down" or "up"
+	end
+end
+
+for _,state in ipairs(validstates) do
+	local boringside = "[combine:64x64:0,0=celevator_cabinet_sides.png:32,0=celevator_cabinet_sides.png:0,32=celevator_cabinet_sides.png:32,32=celevator_cabinet_sides.png"
+	local nname = "celevator:callbutton_"..state[1]
+	local dropname = nname
+	if state[2] then nname = nname.."_upon" end
+	if state[3] then nname = nname.."_downon" end
+	local idle = not (state[2] or state[3])
+	local description = string.format("%s Call Button%s",state[4],(idle and "" or " (on state, you hacker you!)"))
+	minetest.register_node(nname,{
+		description = description,
+		groups = {
+			dig_immediate = 2,
+			not_in_creative_inventory = (idle and 0 or 1),
+			_celevator_callbutton = 1,
+			_celevator_callbutton_has_up = (state[1] == "down" and 0 or 1),
+			_celevator_callbutton_has_down = (state[1] == "up" and 0 or 1),
+			_celevator_callbutton_up_lit = (state[2] and 1 or 0),
+			_celevator_callbutton_down_lit = (state[3] and 1 or 0),
+		},
+		drop = dropname,
+		tiles = {
+			boringside,
+			boringside,
+			boringside,
+			boringside,
+			boringside,
+			makebuttontex(state[1],state[2],state[3])
+		},
+		paramtype = "light",
+		paramtype2 = "facedir",
+		drawtype = "nodebox",
+		node_box = {
+			type = "fixed",
+			fixed = {
+				{-0.5,  -0.5, -0.5,  0.5,  0.5,  0.5 },
+				{-0.16, -0.37,-0.59, 0.17, 0.13,-0.5 },
+			},
+		},
+		on_rightclick = function(pos,_,clicker)
+			if state[1] == "up" then
+				setlight(pos,"up",not state[2])
+			elseif state[1] == "down" then
+				setlight(pos,"down",not state[3])
+			elseif state[1] == "both" then
+				local dir = disambiguatedir(pos,clicker)
+				if dir == "up" then
+					setlight(pos,"up",not state[2])
+				elseif dir == "down" then
+					setlight(pos,"down",not state[3])
+				end
+			end
+		end,
+	})
+end

controller.lua

@@ -0,0 +1,492 @@
+celevator.controller = {}
+
+celevator.controller.iqueue = minetest.deserialize(celevator.storage:get_string("controller_iqueue")) or {}
+
+celevator.controller.equeue = minetest.deserialize(celevator.storage:get_string("controller_equeue")) or {}
+
+celevator.controller.running = {}
+
+local fw,err = loadfile(minetest.get_modpath("celevator")..DIR_DELIM.."controllerfw.lua")
+if not fw then error(err) end
+
+minetest.register_chatcommand("celevator_reloadcontroller",{
+	params = "",
+	description = "Reload celevator controller firmware from disk",
+	privs = {server = true},
+	func = function()
+		local newfw,loaderr = loadfile(minetest.get_modpath("celevator")..DIR_DELIM.."controllerfw.lua")
+		if newfw then
+			fw = newfw
+			return true,"Firmware reloaded successfully"
+		else
+			return false,loaderr
+		end
+	end,
+})
+
+local function after_place(pos,placer)
+	local node = minetest.get_node(pos)
+	local toppos = {x=pos.x,y=pos.y + 1,z=pos.z}
+	local topnode = minetest.get_node(toppos)
+	local placername = placer:get_player_name()
+	if topnode.name ~= "air" then
+		if placer:is_player() then
+			minetest.chat_send_player(placername,"Can't place cabinet - no room for the top half!")
+		end
+		minetest.set_node(pos,{name="air"})
+		return true
+	end
+	if minetest.is_protected(toppos,placername) and not minetest.check_player_privs(placername,{protection_bypass=true}) then
+		if placer:is_player() then
+			minetest.chat_send_player(placername,"Can't place cabinet - top half is protected!")
+			minetest.record_protection_violation(toppos,placername)
+		end
+		minetest.set_node(pos,{name="air"})
+		return true
+	end
+	node.name = "celevator:controller_top"
+	minetest.set_node(toppos,node)
+end
+
+local function ondestruct(pos)
+	pos.y = pos.y + 1
+	local topnode = minetest.get_node(pos)
+	local controllertops = {
+		["celevator:controller_top"] = true,
+		["celevator:controller_top_running"] = true,
+		["celevator:controller_top_open"] = true,
+		["celevator:controller_top_open_running"] = true,
+	}
+	if controllertops[topnode.name] then
+		minetest.set_node(pos,{name="air"})
+	end
+	celevator.controller.equeue[minetest.hash_node_position(pos)] = nil
+	celevator.storage:set_string("controller_equeue",minetest.serialize(celevator.controller.equeue))
+end
+
+local function onrotate(controllerpos,node,user,mode,new_param2)
+	if not minetest.global_exists("screwdriver") then
+		return false
+	end
+	local ret = screwdriver.rotate_simple(controllerpos,node,user,mode,new_param2)
+	minetest.after(0,function(pos)
+		local newnode = minetest.get_node(pos)
+		local param2 = newnode.param2
+		pos.y = pos.y + 1
+		local topnode = minetest.get_node(pos)
+		topnode.param2 = param2
+		minetest.set_node(pos,topnode)
+	end,controllerpos)
+	return ret
+end
+
+local function handlefields(pos,_,fields,sender)
+	local playername = sender and sender:get_player_name() or ""
+	local event = {}
+	event.type = "ui"
+	event.fields = fields
+	event.sender = playername
+	celevator.controller.run(pos,event)
+end
+
+local function controllerleds(pos,running)
+	local toppos = vector.add(pos,vector.new(0,1,0))
+	local node = minetest.get_node(toppos)
+	local sparams = {
+		pos = toppos,
+	}
+	if node.name == "celevator:controller_top_open" and running then
+		node.name = "celevator:controller_top_open_running"
+		minetest.swap_node(toppos,node)
+		minetest.sound_play("celevator_controller_start",sparams,true)
+	elseif node.name == "celevator:controller_top" and running then
+		node.name = "celevator:controller_top_running"
+		minetest.swap_node(toppos,node)
+		minetest.sound_play("celevator_controller_start",sparams,true)
+	elseif node.name == "celevator:controller_top_open_running" and not running then
+		node.name = "celevator:controller_top_open"
+		minetest.swap_node(toppos,node)
+		minetest.sound_play("celevator_controller_stop",sparams,true)
+	elseif node.name == "celevator:controller_top_running" and not running then
+		node.name = "celevator:controller_top"
+		minetest.swap_node(toppos,node)
+		minetest.sound_play("celevator_controller_stop",sparams,true)
+	end
+end
+
+minetest.register_node("celevator:controller",{
+	description = "Controller",
+	groups = {
+		cracky = 1,
+	},
+	paramtype = "light",
+	paramtype2 = "facedir",
+	drawtype = "nodebox",
+	node_box = {
+		type = "fixed",
+		fixed = {
+			{-0.5,-0.5,0,0.5,0.5,0.5},
+		},
+	},
+	selection_box = {
+		type = "fixed",
+		fixed = {
+			{-0.5,-0.5,0,0.5,1.5,0.5},
+		},
+	},
+	tiles = {
+		"celevator_cabinet_sides.png",
+		"celevator_cabinet_sides.png",
+		"celevator_cabinet_sides.png",
+		"celevator_cabinet_sides.png",
+		"celevator_cabinet_sides.png",
+		"celevator_cabinet_front_bottom.png",
+	},
+	after_place_node = after_place,
+	on_destruct = ondestruct,
+	on_rotate = onrotate,
+	on_receive_fields = handlefields,
+	on_construct = function(pos)
+		local meta = minetest.get_meta(pos)
+		meta:set_string("mem",minetest.serialize({}))
+		local event = {}
+		event.type = "program"
+		celevator.controller.run(pos,event)
+	end,
+	on_punch = function(pos,node,puncher)
+		if not puncher:is_player() then
+			return
+		end
+		local name = puncher:get_player_name()
+		if minetest.is_protected(pos,name) and not minetest.check_player_privs(name,{protection_bypass=true}) then
+			minetest.chat_send_player(name,"Can't open cabinet - cabinet is locked.")
+			minetest.record_protection_violation(pos,name)
+			return
+		end
+		node.name = "celevator:controller_open"
+		minetest.swap_node(pos,node)
+		local meta = minetest.get_meta(pos)
+		meta:set_string("formspec",meta:get_string("formspec_hidden"))
+		pos.y = pos.y + 1
+		node = minetest.get_node(pos)
+		if node.name == "celevator:controller_top_running" then
+			node.name = "celevator:controller_top_open_running"
+		else
+			node.name = "celevator:controller_top_open"
+		end
+		minetest.swap_node(pos,node)
+		minetest.sound_play("doors_steel_door_open",{
+			pos = pos,
+			gain = 0.5,
+			max_hear_distance = 10
+		},true)
+	end,
+})
+
+minetest.register_node("celevator:controller_open",{
+	description = "Controller (door open - you hacker you!)",
+	groups = {
+		cracky = 1,
+		not_in_creative_inventory = 1,
+	},
+	paramtype = "light",
+	paramtype2 = "facedir",
+	drawtype = "nodebox",
+	drop = "celevator:controller",
+	node_box = {
+		type = "fixed",
+		fixed = {
+			{-0.5,-0.5,0,0.5,0.5,0.5},
+			{-0.5,-0.5,-0.5,-0.45,0.5,0},
+			{0.45,-0.5,-0.5,0.5,0.5,0},
+		},
+	},
+	selection_box = {
+		type = "fixed",
+		fixed = {
+			{-0.5,-0.5,-0.5,0.5,1.5,0.5},
+		},
+	},
+	tiles = {
+		"celevator_cabinet_sides.png",
+		"celevator_cabinet_sides.png",
+		"celevator_cabinet_front_bottom_open_rside.png",
+		"celevator_cabinet_front_bottom_open_lside.png",
+		"celevator_cabinet_sides.png",
+		"celevator_cabinet_front_bottom_open.png",
+	},
+	after_place_node = after_place,
+	on_destruct = ondestruct,
+	on_rotate = onrotate,
+	on_receive_fields = handlefields,
+	on_punch = function(pos,node,puncher)
+		if not puncher:is_player() then
+			return
+		end
+		node.name = "celevator:controller"
+		minetest.swap_node(pos,node)
+		local meta = minetest.get_meta(pos)
+		meta:set_string("formspec","")
+		pos.y = pos.y + 1
+		node = minetest.get_node(pos)
+		if node.name == "celevator:controller_top_open_running" then
+			node.name = "celevator:controller_top_running"
+		else
+			node.name = "celevator:controller_top"
+		end
+		minetest.swap_node(pos,node)
+		minetest.sound_play("doors_steel_door_close",{
+			pos = pos,
+			gain = 0.5,
+			max_hear_distance = 10
+		},true)
+	end,
+})
+
+minetest.register_node("celevator:controller_top",{
+	description = "Controller (top section - you hacker you!)",
+	groups = {
+		not_in_creative_inventory = 1,
+	},
+	drop = "",
+	paramtype = "light",
+	paramtype2 = "facedir",
+	drawtype = "nodebox",
+	node_box = {
+		type = "fixed",
+		fixed = {
+			{-0.5,-0.5,0,0.5,0.5,0.5},
+		},
+	},
+	selection_box = {
+		type = "fixed",
+		fixed = {
+			{0,0,0,0,0,0},
+		},
+	},
+	tiles = {
+		"celevator_cabinet_sides.png",
+		"celevator_cabinet_sides.png",
+		"celevator_cabinet_sides.png",
+		"celevator_cabinet_sides.png",
+		"celevator_cabinet_sides.png",
+		"celevator_cabinet_front_top.png",
+	},
+})
+
+minetest.register_node("celevator:controller_top_running",{
+	description = "Controller (top section, car in motion - you hacker you!)",
+	groups = {
+		not_in_creative_inventory = 1,
+	},
+	drop = "",
+	paramtype = "light",
+	paramtype2 = "facedir",
+	drawtype = "nodebox",
+	node_box = {
+		type = "fixed",
+		fixed = {
+			{-0.5,-0.5,0,0.5,0.5,0.5},
+		},
+	},
+	selection_box = {
+		type = "fixed",
+		fixed = {
+			{0,0,0,0,0,0},
+		},
+	},
+	tiles = {
+		"celevator_cabinet_sides.png",
+		"celevator_cabinet_sides.png",
+		"celevator_cabinet_sides.png",
+		"celevator_cabinet_sides.png",
+		"celevator_cabinet_sides.png",
+		"celevator_cabinet_front_top.png",
+	},
+})
+
+minetest.register_node("celevator:controller_top_open",{
+	description = "Controller (top section, open - you hacker you!)",
+	groups = {
+		not_in_creative_inventory = 1,
+	},
+	drop = "",
+	paramtype = "light",
+	paramtype2 = "facedir",
+	drawtype = "nodebox",
+	node_box = {
+		type = "fixed",
+		fixed = {
+			{-0.5,-0.5,0,0.5,0.5,0.5},
+			{-0.5,-0.5,-0.5,-0.45,0.5,0},
+			{0.45,-0.5,-0.5,0.5,0.5,0},
+		},
+	},
+	selection_box = {
+		type = "fixed",
+		fixed = {
+			{0,0,0,0,0,0},
+		},
+	},
+	tiles = {
+		"celevator_cabinet_sides.png",
+		"celevator_cabinet_sides.png",
+		"celevator_cabinet_front_top_open_rside.png",
+		"celevator_cabinet_front_top_open_lside.png",
+		"celevator_cabinet_sides.png",
+		{
+			name="celevator_cabinet_front_top_open_stopped.png",
+			animation={type="vertical_frames", aspect_w=32, aspect_h=32, length=2},
+		}
+	},
+})
+
+minetest.register_node("celevator:controller_top_open_running",{
+	description = "Controller (top section, open, car in motion - you hacker you!)",
+	groups = {
+		not_in_creative_inventory = 1,
+	},
+	drop = "",
+	paramtype = "light",
+	paramtype2 = "facedir",
+	drawtype = "nodebox",
+	node_box = {
+		type = "fixed",
+		fixed = {
+			{-0.5,-0.5,0,0.5,0.5,0.5},
+			{-0.5,-0.5,-0.5,-0.45,0.5,0},
+			{0.45,-0.5,-0.5,0.5,0.5,0},
+		},
+	},
+	selection_box = {
+		type = "fixed",
+		fixed = {
+			{0,0,0,0,0,0},
+		},
+	},
+	tiles = {
+		"celevator_cabinet_sides.png",
+		"celevator_cabinet_sides.png",
+		"celevator_cabinet_front_top_open_rside.png",
+		"celevator_cabinet_front_top_open_lside.png",
+		"celevator_cabinet_sides.png",
+		{
+			name="celevator_cabinet_front_top_open_running.png",
+			animation={type="vertical_frames", aspect_w=32, aspect_h=32, length=2},
+		}
+	},
+})
+
+function celevator.controller.iscontroller(pos,call2)
+	local node = minetest.get_node(pos)
+	if node.name == "ignore" and not call2 then
+		minetest.forceload_block(pos)
+		return celevator.controller.iscontroller(pos,true)
+	elseif node.name == "celevator:controller" or node.name == "celevator:controller_open" then
+		return true
+	else
+		return false
+	end
+end
+
+function celevator.controller.finddrive(pos)
+	local node = minetest.get_node(pos)
+	local dir = minetest.facedir_to_dir(node.param2)
+	local drivepos = vector.add(pos,vector.new(0,1,0))
+	drivepos = vector.add(drivepos,vector.rotate_around_axis(dir,vector.new(0,-1,0),math.pi/2))
+	drivepos = vector.round(drivepos)
+	local drivename = minetest.get_node(drivepos).name
+	return drivepos,minetest.registered_nodes[drivename]._celevator_drive_type
+end
+
+function celevator.controller.finish(pos,mem)
+	if not celevator.controller.iscontroller(pos) then
+		return
+	else
+		local drivepos,drivetype = celevator.controller.finddrive(pos)
+		if drivetype then
+			for _,command in ipairs(mem.drive.commands) do
+				if command.command == "moveto" then
+					celevator.drives[drivetype].moveto(drivepos,command.pos)
+				elseif command.command == "setmaxvel" then
+					celevator.drives[drivetype].setmaxvel(drivepos,command.maxvel)
+				elseif command.command == "resetpos" then
+					celevator.drives[drivetype].resetpos(drivepos)
+				elseif command.command == "estop" then
+					celevator.drives[drivetype].estop(drivepos)
+				end
+			end
+		end
+		local meta = minetest.get_meta(pos)
+		local node = minetest.get_node(pos)
+		meta:set_string("mem",minetest.serialize(mem))
+		if node.name == "celevator:controller_open" then meta:set_string("formspec",mem.formspec or "") end
+		meta:set_string("formspec_hidden",mem.formspec or "")
+		meta:set_string("infotext",mem.infotext or "")
+		local hash = minetest.hash_node_position(pos)
+		celevator.controller.iqueue[hash] = mem.interrupts
+		celevator.storage:set_string("controller_iqueue",minetest.serialize(celevator.controller.iqueue))
+		controllerleds(pos,mem.showrunning)
+		celevator.controller.running[hash] = nil
+		if #celevator.controller.equeue[hash] > 0 then
+			local event = celevator.controller.equeue[hash][1]
+			table.remove(celevator.controller.equeue[hash],1)
+			celevator.storage:set_string("controller_equeue",minetest.serialize(celevator.controller.equeue))
+			celevator.controller.run(pos,event)
+		end
+	end
+end
+
+function celevator.controller.run(pos,event)
+	if not celevator.controller.iscontroller(pos) then
+		return
+	else
+		local hash = minetest.hash_node_position(pos)
+		if not celevator.controller.equeue[hash] then
+			celevator.controller.equeue[hash] = {}
+			celevator.storage:set_string("controller_equeue",minetest.serialize(celevator.controller.equeue))
+		end
+		if celevator.controller.running[hash] then
+			table.insert(celevator.controller.equeue[hash],event)
+			celevator.storage:set_string("controller_equeue",minetest.serialize(celevator.controller.equeue))
+			if #celevator.controller.equeue[hash] > 5 then
+				minetest.log("warning","[celevator] [controller] Async process for controller at %s is falling behind, %d events in queue",minetest.pos_to_string(pos),#celevator.controller.equeue[hash])
+			end
+			return
+		end
+		celevator.controller.running[hash] = true
+		local meta = minetest.get_meta(pos)
+		local mem = minetest.deserialize(meta:get_string("mem"))
+		if not mem then
+			minetest.log("error","[celevator] [controller] Failed to load controller memory at "..minetest.pos_to_string(pos))
+			mem = {}
+		end
+		mem.drive = {}
+		mem.drive.commands = {}
+		local drivepos,drivetype = celevator.controller.finddrive(pos)
+		if drivetype then
+			mem.drive.type = drivetype
+			mem.drive.status = celevator.drives[drivetype].getstatus(drivepos)
+		end
+		mem.interrupts = celevator.controller.iqueue[minetest.hash_node_position(pos)] or {}
+		minetest.handle_async(fw,celevator.controller.finish,pos,event,mem)
+	end
+end
+
+function celevator.controller.checkiqueue(dtime)
+	for hash,iqueue in pairs(celevator.controller.iqueue) do
+		local pos = minetest.get_position_from_hash(hash)
+		for iid,time in pairs(iqueue) do
+			iqueue[iid] = time-dtime
+			if iqueue[iid] < 0 then
+				iqueue[iid] = nil
+				local event = {}
+				event.type = "interrupt"
+				event.iid = iid
+				celevator.controller.run(pos,event)
+			end
+		end
+	end
+end
+
+minetest.register_globalstep(celevator.controller.checkiqueue)

controllerfw.lua

@@ -0,0 +1,707 @@
+local pos,event,mem = ...
+
+local function fault(ftype,fatal)
+	if fatal then mem.fatalfault = true end
+	if not mem.activefaults then mem.activefaults = {} end
+	if not mem.faultlog then mem.faultlog = {} end
+	if mem.activefaults[ftype] then return end
+	mem.activefaults[ftype] = true
+	table.insert(mem.faultlog,{ftype = ftype,timestamp = os.time()})
+end
+
+if not mem.drive.status then
+	fault("drivecomm",true)
+	mem.drive.status = {
+		apos = 0,
+		dpos = 0,
+		vel = 0,
+		maxvel = 0,
+	}
+end
+
+local juststarted = false
+
+local modenames = {
+	normal = "Normal Operation",
+	uninit = "Uninitialized",
+	resync = "Position Sync - Floor",
+	bfdemand = "Position Sync - Terminal",
+	fault = "Fault",
+	stop = "Emergency Stop",
+	mrinspect = "Machine Room Inspection",
+	carinspect = "Car Top Inspection",
+	inspconflict = "Inspection Conflict",
+	fs1 = "Fire Service - Phase 1",
+	fs2 = "Fire Service - Phase 2",
+	indep = "Independent Service",
+	capture = "Captured",
+	test = "Test Mode",
+}
+
+local doorstates = {
+	open = "Open",
+	opening = "Opening",
+	closing = "Closing",
+	closed = "Closed",
+	testtiming = "Closed",
+}
+
+local faultnames = {
+	drivecomm = "Lost Communication With Drive",
+}
+
+local function drivecmd(command)
+	table.insert(mem.drive.commands,command)
+end
+
+local function interrupt(time,iid)
+	mem.interrupts[iid] = time
+end
+
+local function getpos()
+	local ret = 0
+	for k,v in ipairs(mem.params.floorheights) do
+		ret = ret+v
+		if ret > mem.drive.status.apos then return k end
+	end
+	return mem.params.floorheights[#mem.params.floorheights]
+end
+
+local function gettarget(floor)
+	local target = 0
+	if floor == 1 then return 0 end
+	for i=1,floor-1,1 do
+		target = target+mem.params.floorheights[i]
+	end
+	return target
+end
+
+local function gotofloor(floor)
+	mem.carmotion = true
+	drivecmd({
+		command = "setmaxvel",
+		maxvel = mem.params.contractspeed
+	})
+	drivecmd({
+		command = "moveto",
+		pos = gettarget(floor)
+	})
+	interrupt(0,"checkdrive")
+	juststarted = true
+end
+
+local function getnextcallabove(dir)
+	for i=getpos(),#mem.params.floorheights,1 do
+		if not dir then
+			if mem.carcalls[i] then
+				return i,"car"
+			elseif mem.upcalls[i] then
+				return i,"up"
+			elseif mem.dncalls[i] then
+				return i,"down"
+			end
+		elseif dir == "up" then
+			if mem.carcalls[i] then
+				return i,"car"
+			elseif mem.upcalls[i] then
+				return i,"up"
+			end
+		elseif dir == "down" then
+			if mem.carcalls[i] then
+				return i,"car"
+			elseif mem.dncalls[i] then
+				return i,"down"
+			end
+		end
+	end
+end
+
+local function getnextcallbelow(dir)
+	for i=getpos(),1,-1 do
+		if not dir then
+			if mem.carcalls[i] then
+				return i,"car"
+			elseif mem.upcalls[i] then
+				return i,"up"
+			elseif mem.dncalls[i] then
+				return i,"down"
+			end
+		elseif dir == "up" then
+			if mem.carcalls[i] then
+				return i,"car"
+			elseif mem.upcalls[i] then
+				return i,"up"
+			end
+		elseif dir == "down" then
+			if mem.carcalls[i] then
+				return i,"car"
+			elseif mem.dncalls[i] then
+				return i,"down"
+			end
+		end
+	end
+end
+
+local function getlowestupcall()
+	for i=1,#mem.params.floornames,1 do
+		if mem.upcalls[i] then return i end
+	end
+end
+
+local function gethighestdowncall()
+	for i=#mem.params.floornames,1,-1 do
+		if mem.dncalls[i] then return i end
+	end
+end
+
+local function open()
+	--TODO: Door operator interface
+	mem.doorstate = "opening"
+	interrupt(2,"opened")
+end
+
+local function close()
+	--TODO: Door operator interface
+	mem.doorstate = "closing"
+	interrupt(2,"closed")
+end
+
+mem.formspec = ""
+
+local function fs(element)
+	mem.formspec = mem.formspec..element
+end
+
+if event.type == "program" then
+	mem.carstate = "uninit"
+	mem.editingfloor = 1
+	mem.doorstate = "closed"
+	mem.carmotion = false
+	mem.carcalls = {}
+	mem.upcalls = {}
+	mem.dncalls = {}
+	mem.screenpage = 1
+	mem.scrollfollowscar = true
+	mem.controllerstopsw = false
+	mem.controllerinspectsw = false
+	mem.cartopinspectsw = false
+	mem.capturesw = false
+	mem.testsw = false
+	mem.activefaults = {}
+	mem.faultlog = {}
+	mem.fatalfault = false
+	if not mem.params then
+		mem.state = "unconfigured"
+		mem.screenstate = "oobe_welcome"
+		mem.params = {
+			contractspeed = 1,
+			floorheights = {5,5,5},
+			floornames = {"1","2","3"},
+			doortimer = 5,
+			groupmode = "simplex",
+		}
+	end
+elseif event.type == "ui" then
+	if mem.screenstate == "oobe_welcome" then
+		if event.fields.license then
+			mem.screenstate = "oobe_license"
+		elseif event.fields.next then
+			mem.screenstate = "oobe_groupmode"
+		end
+	elseif mem.screenstate == "oobe_license" then
+		if event.fields.back then
+			mem.screenstate = "oobe_welcome"
+		end
+	elseif mem.screenstate == "oobe_groupmode" then
+		if event.fields.back then
+			mem.screenstate = "oobe_welcome"
+		elseif event.fields.simplex then
+			mem.screenstate = "oobe_floortable"
+			mem.params.groupmode = "simplex"
+		elseif event.fields.group then
+			mem.screenstate = "oobe_dispatcherconnect"
+			mem.params.groupmode = "group"
+		end
+	elseif mem.screenstate == "oobe_dispatcherconnect" then
+		if event.fields.back then
+			mem.screenstate = "oobe_groupmode"
+		end
+	elseif mem.screenstate == "oobe_floortable" or mem.screenstate == "floortable" then
+		local exp = event.fields.floor and minetest.explode_textlist_event(event.fields.floor) or {}
+		if event.fields.back then
+			mem.screenstate = "oobe_groupmode"
+		elseif event.fields.next then
+			if mem.screenstate == "oobe_floortable" then
+				mem.activefaults = {}
+				mem.faultlog = {}
+				mem.fatalfault = false
+			end
+			mem.state = "configured"
+			mem.screenstate = (mem.screenstate == "oobe_floortable" and "status" or "parameters")
+			mem.screenpage = 1
+			mem.carstate = "bfdemand"
+			if mem.doorstate == "closed" then
+				drivecmd({
+					command = "setmaxvel",
+					maxvel = mem.params.contractspeed,
+				})
+				drivecmd({command = "resetpos"})
+				interrupt(0.1,"checkdrive")
+				mem.carmotion = true
+				juststarted = true
+			else
+				close()
+			end
+		elseif exp.type == "CHG" then
+			mem.editingfloor = #mem.params.floornames-exp.index+1
+		elseif exp.type == "DCL" then
+			mem.editingfloor = #mem.params.floornames-exp.index+1
+			mem.screenstate = (mem.screenstate == "oobe_floortable" and "oobe_floortable_edit" or "floortable_edit")
+		elseif event.fields.edit then
+			mem.screenstate = (mem.screenstate == "oobe_floortable" and "oobe_floortable_edit" or "floortable_edit")
+		elseif event.fields.add then
+			table.insert(mem.params.floorheights,5)
+			table.insert(mem.params.floornames,tostring(#mem.params.floornames+1))
+		elseif event.fields.remove then
+			table.remove(mem.params.floorheights,mem.editingfloor)
+			table.remove(mem.params.floornames,mem.editingfloor)
+			mem.editingfloor = math.max(1,mem.editingfloor-1)
+		elseif event.fields.moveup then
+			local height = mem.params.floorheights[mem.editingfloor]
+			local name = mem.params.floornames[mem.editingfloor]
+			table.remove(mem.params.floorheights,mem.editingfloor)
+			table.remove(mem.params.floornames,mem.editingfloor)
+			table.insert(mem.params.floorheights,mem.editingfloor+1,height)
+			table.insert(mem.params.floornames,mem.editingfloor+1,name)
+			mem.editingfloor = mem.editingfloor + 1
+		elseif event.fields.movedown then
+			local height = mem.params.floorheights[mem.editingfloor]
+			local name = mem.params.floornames[mem.editingfloor]
+			table.remove(mem.params.floorheights,mem.editingfloor)
+			table.remove(mem.params.floornames,mem.editingfloor)
+			table.insert(mem.params.floorheights,mem.editingfloor-1,height)
+			table.insert(mem.params.floornames,mem.editingfloor-1,name)
+			mem.editingfloor = mem.editingfloor - 1
+		end
+	elseif mem.screenstate == "oobe_floortable_edit" or mem.screenstate == "floortable_edit" then
+		if event.fields.back then
+			mem.screenstate = (mem.screenstate == "oobe_floortable_edit" and "oobe_floortable" or "floortable")
+			local height = tonumber(event.fields.height)
+			if height then
+				height = math.floor(height+0.5)
+				mem.params.floorheights[mem.editingfloor] = math.max(0,height)
+			end
+			mem.params.floornames[mem.editingfloor] = string.sub(event.fields.name,1,256)
+		end
+	elseif mem.screenstate == "parameters" then
+		if event.fields.save then
+			mem.screenstate = "status"
+			local doortimer = tonumber(event.fields.doortimer)
+			if doortimer and doortimer > 0 and doortimer <= 30 then
+				mem.params.doortimer = doortimer
+			end
+			local contractspeed = tonumber(event.fields.contractspeed)
+			if contractspeed and contractspeed >= 0.1 and contractspeed <= 20 then
+				mem.params.contractspeed = contractspeed
+			end
+		elseif event.fields.floortable then
+			mem.screenstate = "floortable"
+		elseif event.fields.cancel then
+			mem.screenstate = "status"
+		end
+	elseif mem.screenstate == "status" then
+		for i=1,#mem.params.floornames,1 do
+			if event.fields[string.format("carcall%d",i)] and (mem.carstate == "normal" or mem.carstate == "test" or mem.carstate == "capture") then
+				mem.carcalls[i] = true
+			elseif event.fields[string.format("upcall%d",i)] and mem.carstate == "normal" and not mem.capturesw then
+				mem.upcalls[i] = true
+			elseif event.fields[string.format("downcall%d",i)] and mem.carstate == "normal" and not mem.capturesw then
+				mem.dncalls[i] = true
+			end
+		end
+		if event.fields.scrollup then
+			mem.screenpage = mem.screenpage + 1
+			mem.scrollfollowscar = false
+		elseif event.fields.scrolldown then
+			mem.screenpage = mem.screenpage - 1
+			mem.scrollfollowscar = false
+		elseif event.fields.scrollfollowscar then
+			mem.scrollfollowscar = (event.fields.scrollfollowscar == "true")
+		elseif event.fields.stopsw then
+			mem.controllerstopsw = not mem.controllerstopsw
+		elseif event.fields.inspectsw then
+			mem.controllerinspectsw = not mem.controllerinspectsw
+		elseif event.fields.capturesw then
+			mem.capturesw = not mem.capturesw
+		elseif event.fields.testsw then
+			mem.testsw = not mem.testsw
+		elseif event.fields.inspectup and mem.carstate == "mrinspect" and mem.doorstate == "closed" and getpos() < #mem.params.floornames then
+			mem.carmotion = true
+			juststarted = true
+			drivecmd({
+				command = "setmaxvel",
+				maxvel = 0.2,
+			})
+			drivecmd({
+				command = "moveto",
+				pos = math.floor(mem.drive.status.apos)+1
+			})
+		elseif event.fields.inspectdown and mem.carstate == "mrinspect" and mem.doorstate == "closed" and mem.drive.status.apos-1 >= 0 then
+			mem.carmotion = true
+			juststarted = true
+			drivecmd({
+				command = "setmaxvel",
+				maxvel = 0.2,
+			})
+			drivecmd({
+				command = "moveto",
+				pos = math.floor(mem.drive.status.apos)-1
+			})
+		elseif event.fields.parameters then
+			mem.screenstate = "parameters"
+		elseif event.fields.faults then
+			mem.screenstate = "faults"
+		end
+	elseif mem.screenstate == "faults" then
+		if event.fields.back then
+			mem.screenstate = "status"
+		elseif event.fields.clear then
+			mem.faultlog = {}
+			mem.activefaults = {}
+			mem.fatalfault = false
+		end
+	end
+elseif event.iid == "opened" and mem.doorstate == "opening" then
+	mem.doorstate = "open"
+	if mem.carstate == "normal" then
+		interrupt(mem.params.doortimer,"close")
+	end
+elseif event.iid == "close" and mem.doorstate == "open" then
+	close()
+elseif event.iid == "closed" and (mem.doorstate == "closing" or mem.doorstate == "testtiming") then
+	mem.doorstate = "closed"
+	if mem.carstate == "bfdemand" then
+			drivecmd({
+				command = "setmaxvel",
+				maxvel = mem.params.contractspeed,
+			})
+			drivecmd({command = "resetpos"})
+			interrupt(0.1,"checkdrive")
+			mem.carmotion = true
+			juststarted = true
+	elseif mem.carstate == "resync" then
+			gotofloor(getpos())
+			interrupt(0.1,"checkdrive")
+			mem.carmotion = true
+			juststarted = true
+	end
+end
+
+local oldstate = mem.carstate
+
+if mem.fatalfault then
+	mem.carstate = "fault"
+	drivecmd({command="estop"})
+	mem.carcalls = {}
+	mem.upcalls = {}
+	mem.dncalls = {}
+	mem.direction = nil
+elseif mem.controllerstopsw or mem.screenstate == "floortable" or mem.screenstate == "floortable_edit" then
+	mem.carstate = "stop"
+	drivecmd({command="estop"})
+	mem.carcalls = {}
+	mem.upcalls = {}
+	mem.dncalls = {}
+	mem.direction = nil
+elseif mem.controllerinspectsw and not mem.cartopinspectsw then
+	mem.carstate = "mrinspect"
+	mem.carcalls = {}
+	mem.upcalls = {}
+	mem.dncalls = {}
+	mem.direction = nil
+	if oldstate ~= "mrinspect" then drivecmd({command="estop"}) end
+elseif mem.testsw then
+	mem.upcalls = {}
+	mem.dncalls = {}
+	mem.carstate = "test"
+elseif mem.capturesw then
+	mem.upcalls = {}
+	mem.dncalls = {}
+	if not mem.direction then mem.carstate = "capture" end
+else
+	if oldstate == "stop" or oldstate == "mrinspect" or oldstate == "fault" then
+		mem.carstate = "resync"
+		gotofloor(getpos())
+	elseif oldstate == "test" or oldstate == "capture" then
+		mem.carstate = "normal"
+	end
+end
+
+if mem.carmotion then
+	mem.carmotion = (mem.drive.status.vel ~= 0) or juststarted
+	if mem.carmotion then
+		interrupt(0.1,"checkdrive")
+	else
+		if mem.carstate == "normal" then
+			mem.carcalls[getpos()] = nil
+			if mem.direction == "up" then
+				mem.upcalls[getpos()] = nil
+			elseif mem.direction == "down" then
+				mem.dncalls[getpos()] = nil
+			end
+			if getpos() >= #mem.params.floornames then
+				mem.direction = "down"
+			elseif getpos() <= 1 then
+				mem.direction = "up"
+			end
+			open()
+		elseif mem.carstate == "test" then
+			mem.carcalls[getpos()] = nil
+			mem.doorstate = "testtiming"
+			interrupt(5,"closed")
+			if getpos() >= #mem.params.floornames then
+				mem.direction = "down"
+			elseif getpos() <= 1 then
+				mem.direction = "up"
+			end
+		elseif mem.carstate == "bfdemand" or mem.carstate == "resync" then
+			mem.carstate = "normal"
+		end
+	end
+end
+
+if (mem.carstate == "normal" or mem.carstate == "capture" or mem.carstate == "test") and mem.doorstate == "closed" and not mem.carmotion then
+	if mem.direction == "up" then
+		if getnextcallabove("up") then
+			mem.direction = "up"
+			gotofloor(getnextcallabove("up"))
+		elseif gethighestdowncall() then
+			mem.direction = "down"
+			gotofloor(gethighestdowncall())
+		elseif getlowestupcall() then
+			gotofloor(getlowestupcall())
+		elseif getnextcallbelow("down") then
+			mem.direction = "down"
+			gotofloor(getnextcallbelow("down"))
+		else
+			mem.direction = nil
+		end
+	elseif mem.direction == "down" then
+		if getnextcallbelow("down") then
+			gotofloor(getnextcallbelow("down"))
+		elseif getlowestupcall() then
+			mem.direction = "up"
+			gotofloor(getlowestupcall())
+		elseif gethighestdowncall() then
+			gotofloor(gethighestdowncall())
+		elseif getnextcallabove("up") then
+			mem.direction = "up"
+			gotofloor(getnextcallabove())
+		else
+			mem.direction = nil
+		end
+	else
+		if getnextcallabove("up") then
+			mem.direction = "up"
+			gotofloor(getnextcallabove())
+		elseif getnextcallbelow("down") then
+			mem.direction = "down"
+			gotofloor(getnextcallbelow("down"))
+		elseif getlowestupcall() then
+			mem.direction = "up"
+			gotofloor(getlowestupcall())
+		elseif gethighestdowncall() then
+			mem.direction = "down"
+			gotofloor(gethighestdowncall())
+		end
+	end
+	if mem.carstate == "normal" and mem.capturesw and not mem.direction then
+		mem.upcalls = {}
+		mem.dncalls = {}
+		mem.carstate = "capture"
+	elseif mem.carstate == "capture" and mem.direction then
+		mem.carstate = "normal"
+	end
+end
+
+if mem.scrollfollowscar and mem.screenstate == "status" then
+	mem.screenpage = math.floor((getpos()-1)/10)+1
+end
+
+fs("formspec_version[6]")
+fs("size[16,12]")
+fs("background9[0,0;16,12;celevator_fs_bg.png;true;3]")
+if mem.screenstate == "oobe_welcome" then
+	fs("image[6,1;4,2;celevator_logo.png]")
+	fs("label[1,4;Welcome to your new MTronic XT elevator controller!]")
+	fs("label[1,4.5;This setup wizard is designed to get your elevator up and running as quickly as possible.]")
+	fs("label[1,5.5;Press Next to begin.]")
+	fs("button[1,10;2,1;license;License Info]")
+	fs("button[13,10;2,1;next;Next >]")
+elseif mem.screenstate == "oobe_license" then
+	local licensefile = io.open(minetest.get_modpath("celevator")..DIR_DELIM.."COPYING")
+	local license = minetest.formspec_escape(licensefile:read("*all"))
+	licensefile:close()
+	fs("textarea[1,1;14,8;license;This applies to the whole celevator mod\\, not just this controller:;"..license.."]")
+	fs("button[7,10.5;2,1;back;OK]")
+elseif mem.screenstate == "oobe_groupmode" then
+	fs("button[1,10;2,1;back;< Back]")
+	fs("label[1,1;Select a group operation mode:]")
+	fs("button[1,3;2,1;simplex;Simplex]")
+	fs("label[1,4.5;This will be the only elevator in the group. Hall calls will be handled by this controller.]")
+	fs("button[1,6;2,1;group;Group]")
+	fs("label[1,7.5;This elevator will participate in a group with others. Hall calls will be handled by a dispatcher. (not implemented)]")
+elseif mem.screenstate == "oobe_dispatcherconnect" then
+	fs("button[1,10;2,1;back;< Back]")
+	fs("label[1,1;Not yet implemented. Press Back.]")
+elseif mem.screenstate == "oobe_floortable" or mem.screenstate == "floortable" then
+	if mem.screenstate == "oobe_floortable" then
+		fs("label[1,1;Enter details of all floors this elevator will serve, then press Done.]")
+		fs("button[1,10;2,1;back;< Back]")
+		fs("button[13,10;2,1;next;Done >]")
+	else
+		fs("label[1,1;EDIT FLOOR TABLE]")
+		fs("button[1,10;2,1;next;Done]")
+	end
+	fs("textlist[1,2;6,7;floor;")
+	for i=#mem.params.floornames,1,-1 do
+		fs(minetest.formspec_escape(string.format("%d - Height: %d - PI: %s",i,mem.params.floorheights[i],mem.params.floornames[i]))..(i==1 and "" or ","))
+	end
+	fs(";"..tostring(#mem.params.floornames-mem.editingfloor+1)..";false]")
+	fs("button[8,2;2,1;add;New Floor]")
+	fs("button[8,3.5;2,1;edit;Edit Floor]")
+	if #mem.params.floornames > 2 then fs("button[8,5;2,1;remove;Remove Floor]") end
+	if mem.editingfloor < #mem.params.floornames then fs("button[8,6.5;2,1;moveup;Move Up]") end
+	if mem.editingfloor > 1 then fs("button[8,8;2,1;movedown;Move Down") end
+elseif mem.screenstate == "oobe_floortable_edit" or mem.screenstate == "floortable_edit" then
+	if mem.screenstate == "oobe_floortable_edit" then
+		fs("button[7,10.5;2,1;back;OK]")
+		fs("label[1,5;The Floor Height is the distance (in meters/nodes) from the floor level of this floor to the floor level of the next floor.]")
+		fs("label[1,5.5;(not used at the highest floor)]")
+		fs("label[1,6.5;The Floor Name is how the floor will be displayed on the position indicators.]")
+	else
+		fs("button[7,10.5;2,1;save;Save]")
+	end
+	fs("label[1,1;Editing floor "..tostring(mem.editingfloor).."]")
+	fs("field[1,3;3,1;height;Floor Height;"..tostring(mem.params.floorheights[mem.editingfloor]).."]")
+	fs("field[5,3;3,1;name;Floor Name;"..minetest.formspec_escape(mem.params.floornames[mem.editingfloor]).."]")
+elseif mem.screenstate == "status" then
+	fs("style_type[image_button;font=mono;font_size=*0.75]")
+	fs("box[12,2.5;0.1,9;#AAAAAAFF]")
+	fs("box[13.12,2.5;0.05,9;#AAAAAAFF]")
+	fs("box[14.12,2.5;0.05,9;#AAAAAAFF]")
+	fs("box[15.25,2.5;0.1,9;#AAAAAAFF]")
+	fs("label[12.5,2;UP]")
+	fs("label[13.38,2;CAR]")
+	fs("label[14.25,2;DOWN]")
+	local maxfloor = #mem.params.floornames
+	local bottom = (mem.screenpage-1)*10+1
+	for i=0,9,1 do
+		local ypos = 11-(i*0.9)
+		local floornum = bottom+i
+		if floornum > maxfloor then break end
+		fs(string.format("label[11.25,%f;%s]",ypos,mem.params.floornames[floornum]))
+		local ccdot = mem.carcalls[floornum] and "*" or ""
+		if getpos() == floornum then
+			local cargraphics = {
+				open = "\\[   \\]",
+				opening = "\\[< >\\]",
+				closing = "\\[> <\\]",
+				closed = "\\[ | \\]",
+				testtiming = "\\[ | \\]",
+			}
+			ccdot = cargraphics[mem.doorstate]
+			if mem.direction == "up" then
+				ccdot = minetest.colorize("#55FF55",ccdot)
+			elseif mem.direction == "down" then
+				ccdot = minetest.colorize("#FF5555",ccdot)
+			end
+		end
+		fs(string.format("image_button[13.25,%f;0.75,0.75;celevator_fs_bg.png;carcall%d;%s]",ypos-0.25,floornum,ccdot))
+		if floornum < maxfloor then
+			local arrow = mem.upcalls[floornum] and minetest.colorize("#55FF55","^") or ""
+			fs(string.format("image_button[12.25,%f;0.75,0.75;celevator_fs_bg.png;upcall%d;%s]",ypos-0.25,floornum,arrow))
+		end
+		if floornum > 1 then
+			local arrow = mem.dncalls[floornum] and minetest.colorize("#FF5555","v") or ""
+			fs(string.format("image_button[14.25,%f;0.75,0.75;celevator_fs_bg.png;downcall%d;%s]",ypos-0.25,floornum,arrow))
+		end
+	end
+	if maxfloor > 10 then
+		fs(string.format("checkbox[13,1.25;scrollfollowscar;Follow Car;%s]",tostring(mem.scrollfollowscar)))
+		if bottom+9 < maxfloor then
+			fs("image_button[12.75,0.25;0.75,0.75;celevator_menu_arrow.png;scrollup;;false;false;celevator_menu_arrow.png]")
+		end
+		if bottom > 1 then
+			fs("image_button[13.87,0.25;0.75,0.75;celevator_menu_arrow.png^\\[transformFY;scrolldown;;false;false;celevator_menu_arrow.png^\\[transformFY]")
+		end
+	end
+	fs("label[1,1;CAR STATUS]")
+	fs(string.format("label[1,2;%s]",modenames[mem.carstate]))
+	fs(string.format("label[1,2.5;Doors %s]",doorstates[mem.doorstate]))
+	fs(string.format("label[1,3;Position: %0.02fm Speed: %+0.02fm/s PI: %s]",mem.drive.status.apos,mem.drive.status.vel,minetest.formspec_escape(mem.params.floornames[getpos()])))
+	if #mem.faultlog > 0 then
+		fs("label[1,3.5;Fault(s) Active]")
+	else
+		fs("label[1,3.5;No Current Faults]")
+	end
+	fs("button[1,10;3,1;faults;Fault History]")
+	fs("button[4.5,10;3,1;parameters;Edit Parameters]")
+	fs("style[*;font=mono]")
+	local stopswimg = "celevator_toggle_switch.png"..(mem.controllerstopsw and "^\\[transformFY" or "")
+	fs(string.format("image_button[1,5;1,1.33;%s;stopsw;;false;false;%s]",stopswimg,stopswimg))
+	fs("label[1.3,4.75;RUN]")
+	fs("label[1.2,6.6;STOP]")
+	local captureswimg = "celevator_toggle_switch.png"..(mem.capturesw and "" or "^\\[transformFY")
+	fs(string.format("image_button[3,5;1,1.33;%s;capturesw;;false;false;%s]",captureswimg,captureswimg))
+	fs("label[3,4.75;CAPTURE]")
+	local testswimg = "celevator_toggle_switch.png"..(mem.testsw and "" or "^\\[transformFY")
+	fs(string.format("image_button[5,5;1,1.33;%s;testsw;;false;false;%s]",testswimg,testswimg))
+	fs("label[5.23,4.75;TEST]")
+	local inspectswimg = "celevator_toggle_switch.png"..(mem.controllerinspectsw and "" or "^\\[transformFY")
+	fs(string.format("image_button[1,8;1,1.33;%s;inspectsw;;false;false;%s]",inspectswimg,inspectswimg))
+	fs("label[1.05,7.75;INSPECT]")
+	fs("label[1.1,9.6;NORMAL]")
+	fs(string.format("image_button[3,8.25;1,1;%s;inspectup;;false;false;%s]","celevator_button_black.png","celevator_button_black.png"))
+	fs("label[3.4,7.75;UP]")
+	fs(string.format("image_button[5,8.25;1,1;%s;inspectdown;;false;false;%s]","celevator_button_black.png","celevator_button_black.png"))
+	fs("label[5.25,7.75;DOWN]")
+elseif mem.screenstate == "parameters" then
+	fs("label[1,1;EDIT PARAMETERS]")
+	fs("button[1,10;3,1;save;Save]")
+	fs("button[4.5,10;3,1;cancel;Cancel]")
+	fs("button[8,10;3,1;floortable;Edit Floor Table]")
+	fs(string.format("field[1,3;3,1;doortimer;Door Dwell Timer;%0.1f]",mem.params.doortimer))
+	fs(string.format("field[1,5;3,1;contractspeed;Contract Speed (m/s);%0.1f]",mem.params.contractspeed))
+elseif mem.screenstate == "faults" then
+	fs("label[1,1;FAULT HISTORY]")
+	if #mem.faultlog > 0 then
+		for i=0,9,1 do
+			if #mem.faultlog-i >= 1 then
+				local currfault = mem.faultlog[#mem.faultlog-i]
+				local date = os.date("*t",currfault.timestamp)
+				fs(string.format("label[1,%0.1f;%04d-%02d-%02d %02d:%02d:%02d - %s]",2+i,date.year,date.month,date.day,date.hour,date.min,date.sec,faultnames[currfault.ftype]))
+			end
+		end
+	else
+		fs("label[1,2;No Current Faults]")
+	end
+	fs("button[1,10;3,1;back;Back]")
+	fs("button[4.5,10;3,1;clear;Clear]")
+end
+
+local arrow = " "
+if mem.drive.status.dpos > mem.drive.status.apos then
+	arrow = "^"
+elseif mem.drive.status.dpos < mem.drive.status.apos then
+	arrow = "v"
+end
+mem.infotext = string.format("Floor %s %s - %s - Doors %s",mem.params.floornames[getpos()],arrow,modenames[mem.carstate],doorstates[mem.doorstate])
+
+if mem.drive.type then
+	mem.showrunning = mem.drive.status.vel ~= 0
+else
+	mem.showrunning = false
+end
+
+return pos,mem

drive_null.lua

@@ -0,0 +1,206 @@
+celevator.drives.null = {
+	name = "Null Drive",
+	description = "Simulation only, no movement, for testing and demonstration",
+	nname = "celevator:drive_null",
+	soundhandles = {},
+}
+
+local function update_ui(pos)
+	local meta = minetest.get_meta(pos)
+	local apos = tonumber(meta:get_string("apos")) or 0
+	local status = "Idle"
+	local vel = tonumber(meta:get_string("vel")) or 0
+	if vel > 0 then
+		status = string.format("Running: Up, %0.02f m/s",vel)
+	elseif vel < 0 then
+		status = string.format("Running: Down, %0.02f m/s",math.abs(vel))
+	end
+	meta:set_string("infotext",string.format("Null Drive - %s - Position: %0.02f m",status,apos))
+end
+
+local function playbuzz(pos)
+	local hash = minetest.hash_node_position(pos)
+	if celevator.drives.null.soundhandles[hash] == "cancel" then return end
+	celevator.drives.null.soundhandles[hash] = minetest.sound_play("celevator_drive_run",{
+		pos = pos,
+		loop = true,
+		gain = 0.4,
+	})
+end
+
+local function startbuzz(pos)
+	local hash = minetest.hash_node_position(pos)
+	if celevator.drives.null.soundhandles[hash] == "cancel" then
+		celevator.drives.null.soundhandles[hash] = nil
+		return
+	end
+	if celevator.drives.null.soundhandles[hash] then return end
+	celevator.drives.null.soundhandles[hash] = "pending"
+	minetest.after(0.5,playbuzz,pos)
+end
+
+local function stopbuzz(pos)
+	local hash = minetest.hash_node_position(pos)
+	if not celevator.drives.null.soundhandles[hash] then return end
+	if celevator.drives.null.soundhandles[hash] == "pending" then
+		celevator.drives.null.soundhandles[hash] = "cancel"
+	end
+	if type(celevator.drives.null.soundhandles[hash]) ~= "string" then
+		minetest.sound_stop(celevator.drives.null.soundhandles[hash])
+		celevator.drives.null.soundhandles[hash] = nil
+	end
+end
+
+minetest.register_node("celevator:drive_null",{
+	description = celevator.drives.null.name,
+	groups = {
+		cracky = 1,
+	},
+	tiles = {
+		"celevator_cabinet_sides.png",
+		"celevator_cabinet_sides.png",
+		"celevator_cabinet_sides.png",
+		"celevator_cabinet_sides.png",
+		"celevator_cabinet_sides.png",
+		"celevator_drive_front.png",
+	},
+	paramtype = "light",
+	paramtype2 = "facedir",
+	drawtype = "nodebox",
+	node_box = {
+		type = "fixed",
+		fixed = {
+			{-0.4,-0.4,-0.1,0.4,0.4,0.5},
+			{-0.5,-0.3,0.4,-0.4,-0.22,0.32},
+			{-0.5,0.22,0.4,-0.4,0.3,0.32},
+		},
+	},
+	_celevator_drive_type = "null",
+	after_place_node = function(pos)
+		local meta = minetest.get_meta(pos)
+		meta:set_string("apos","0")
+		meta:set_string("dpos","0")
+		meta:set_string("vel","0")
+		meta:set_string("maxvel","0.2")
+		update_ui(pos)
+	end,
+	on_destruct = stopbuzz,
+})
+
+function celevator.drives.null.step(dtime)
+	local nulldrives_running = minetest.deserialize(celevator.storage:get_string("nulldrives_running")) or {}
+	local save = false
+	for i,hash in ipairs(nulldrives_running) do
+		save = true
+		local pos = minetest.get_position_from_hash(hash)
+		local node = minetest.get_node(pos)
+		local sound = false
+		if node.name == "ignore" then
+			minetest.forceload_block(pos,true)
+		elseif node.name ~= "celevator:drive_null" then
+			table.remove(nulldrives_running,i)
+		else
+			local meta = minetest.get_meta(pos)
+			local apos = tonumber(meta:get_string("apos")) or 0
+			local dpos = tonumber(meta:get_string("dpos")) or 0
+			local maxvel = tonumber(meta:get_string("maxvel")) or 0.2
+			local dremain = math.abs(dpos-apos)
+			local vel = maxvel
+			if dremain < 0.5 then vel = math.min(0.2,vel) end
+			local stepdist = vel*dtime
+			if dpos > apos then
+				local newpos = apos + stepdist
+				if newpos < dpos then
+					meta:set_string("apos",tostring(newpos))
+					meta:set_string("vel",vel)
+					sound = true
+				else
+					meta:set_string("apos",tostring(dpos))
+					meta:set_string("vel",0)
+					sound = false
+				end
+			elseif dpos < apos then
+				local newpos = apos - stepdist
+				if newpos > dpos then
+					meta:set_string("apos",tostring(newpos))
+						meta:set_string("vel",0-vel)
+					sound = true
+				else
+					meta:set_string("apos",tostring(dpos))
+					meta:set_string("vel",0)
+					sound = false
+				end
+			else
+				table.remove(nulldrives_running,i)
+			end
+		end
+		update_ui(pos)
+		if sound then
+			startbuzz(pos)
+		else
+			stopbuzz(pos)
+		end
+	end
+	if save then
+		celevator.storage:set_string("nulldrives_running",minetest.serialize(nulldrives_running))
+	end
+end
+
+minetest.register_globalstep(celevator.drives.null.step)
+
+function celevator.drives.null.moveto(pos,target)
+	local meta = minetest.get_meta(pos)
+	meta:set_string("dpos",tostring(target))
+	local hash = minetest.hash_node_position(pos)
+	local nulldrives_running = minetest.deserialize(celevator.storage:get_string("nulldrives_running")) or {}
+	local running = false
+	for _,dhash in ipairs(nulldrives_running) do
+		if hash == dhash then
+			running = true
+			break
+		end
+	end
+	if not running then
+		table.insert(nulldrives_running,hash)
+		celevator.storage:set_string("nulldrives_running",minetest.serialize(nulldrives_running))
+	end
+end
+
+function celevator.drives.null.resetpos(pos)
+	celevator.drives.null.moveto(pos,0)
+end
+
+function celevator.drives.null.estop(pos)
+	local meta = minetest.get_meta(pos)
+	meta:set_string("dpos",meta:get_string("apos"))
+	meta:set_string("vel","0")
+end
+
+function celevator.drives.null.setmaxvel(pos,maxvel)
+	local meta = minetest.get_meta(pos)
+	meta:set_string("maxvel",tostring(maxvel))
+end
+
+function celevator.drives.null.rezero(pos)
+	celevator.drives.null.moveto(pos,0)
+end
+
+function celevator.drives.null.getstatus(pos,call2)
+	local node = minetest.get_node(pos)
+	if node.name == "ignore" and not call2 then
+		minetest.forceload_block(pos,true)
+		return celevator.drives.null.get_status(pos,true)
+	elseif node.name ~= "celevator:drive_null" then
+		minetest.log("error","[celevator] [null drive] Could not load drive status at "..minetest.pos_to_string(pos))
+		return
+	else
+		local meta = minetest.get_meta(pos)
+		local ret = {}
+		ret.apos = tonumber(meta:get_string("apos")) or 0
+		ret.dpos = tonumber(meta:get_string("dpos")) or 0
+		ret.vel = tonumber(meta:get_string("vel")) or 0
+		ret.maxvel = tonumber(meta:get_string("maxvel")) or 0.2
+		ret.neareststop = ret.apos
+		return ret
+	end
+end

framework.lua

@@ -0,0 +1,4 @@
+celevator = {
+	drives = {},
+	storage = minetest.get_mod_storage(),
+}

init.lua

@@ -0,0 +1,10 @@
+local components = {
+	"framework",
+	"drive_null",
+	"controller",
+	"callbuttons",
+}
+
+for _,v in ipairs(components) do
+	dofile(string.format("%s%s%s.lua",minetest.get_modpath("celevator"),DIR_DELIM,v))
+end

mod.conf

@@ -0,0 +1,2 @@
+name = celevator
+description = WIP