Smoother link of processing cycles to ABM cycles

Make the generic processing machine code willing to complete more than
one processing cycle in one ABM cycle, and more generally to carry
over leftover processing effort after completing a processing cycle.
The src_time meta item now represents accumulated processing effort
(time multiplied by speed) in a scaled form (to retain fractions),
rather than just time in integral seconds.  This affects the MV furnace,
with speed 4 and most recipe times being 3 s, and will be essential for
faster furnaces.

technic/machines/register/machine_base.lua

@@ -15,6 +15,10 @@ local tube = {
 	connect_sides = {left = 1, right = 1, back = 1, top = 1, bottom = 1},
 }
 
+local function round(v)
+	return math.floor(v + 0.5)
+end
+
 function technic.register_base_machine(data)
 	local typename = data.typename
 	local input_size = technic.recipes[typename].input_size
@@ -70,27 +74,29 @@ function technic.register_base_machine(data)
 			technic.handle_machine_pipeworks(pos, tube_upgrade)
 		end
 
+		local powered = eu_input >= machine_demand[EU_upgrade+1]
+		if powered then
+			meta:set_int("src_time", meta:get_int("src_time") + round(data.speed*10))
+		end
+		while true do
 			local result = technic.get_recipe(typename, inv:get_list("src"))
-
 			if not result then
 				technic.swap_node(pos, machine_node)
 				meta:set_string("infotext", S("%s Idle"):format(machine_desc_tier))
 				meta:set_int(tier.."_EU_demand", 0)
+				meta:set_int("src_time", 0)
 				return
 			end
-		
+			meta:set_int(tier.."_EU_demand", machine_demand[EU_upgrade+1])
-		if eu_input < machine_demand[EU_upgrade+1] then
-			-- Unpowered - go idle
-			technic.swap_node(pos, machine_node)
-			meta:set_string("infotext", S("%s Unpowered"):format(machine_desc_tier))
-		elseif eu_input >= machine_demand[EU_upgrade+1] then
-			-- Powered	
 			technic.swap_node(pos, machine_node.."_active")
 			meta:set_string("infotext", S("%s Active"):format(machine_desc_tier))
-
+			if meta:get_int("src_time") < round(result.time*10) then
-			meta:set_int("src_time", meta:get_int("src_time") + 1)
+				if not powered then
-			if meta:get_int("src_time") >= result.time / data.speed then
+					technic.swap_node(pos, machine_node)
-				meta:set_int("src_time", 0)
+					meta:set_string("infotext", S("%s Unpowered"):format(machine_desc_tier))
+				end
+				return
+			end
 			local output = result.output
 			if type(output) ~= "table" then output = { output } end
 			local output_stacks = {}
@@ -107,15 +113,15 @@ function technic.register_base_machine(data)
 				end
 				inv:add_item("dst_tmp", o)
 			end
-				if room_for_output then
+			if not room_for_output then
+				meta:set_int("src_time", round(result.time*10))
+				return
+			end
+			meta:set_int("src_time", meta:get_int("src_time") - round(result.time*10))
 			inv:set_list("src", result.new_input)
 			inv:set_list("dst", inv:get_list("dst_tmp"))
-				else
 		end
 	end
-		end
-		meta:set_int(tier.."_EU_demand", machine_demand[EU_upgrade+1])
-	end
 	
 	minetest.register_node("technic:"..ltier.."_"..machine_name, {
 		description = machine_desc:format(tier),