Implement comparator accurately and remove WIP, remove ABMs for comparators and make updates triggered instead of polled, changes to redstone power transmission

mods/ITEMS/REDSTONE/mcl_comparators/init.lua

@@ -1,4 +1,6 @@
 local S = minetest.get_translator(minetest.get_current_modname())
+mcl_comparators = {}
+local mod = mcl_comparators
 
 -- Functions that get the input/output rules of the comparator
 
@@ -10,7 +12,6 @@ local function comparator_get_output_rules(node)
 	return rules
 end
 
-
 local function comparator_get_input_rules(node)
 	local rules = {
 		-- we rely on this order in update_self below
@@ -24,117 +25,73 @@ local function comparator_get_input_rules(node)
 	return rules
 end
 
-
--- Functions that are called after the delay time
-
-local function comparator_turnon(params)
-	local rules = comparator_get_output_rules(params.node)
-	mesecon.receptor_on(params.pos, rules)
-end
-
-
-local function comparator_turnoff(params)
-	local rules = comparator_get_output_rules(params.node)
-	mesecon.receptor_off(params.pos, rules)
-end
-
-
--- Functions that set the correct node type an schedule a turnon/off
-
-local function comparator_activate(pos, node)
-	local def = minetest.registered_nodes[node.name]
-	local onstate = def.comparator_onstate
-	if onstate then
-		minetest.swap_node(pos, { name = onstate, param2 = node.param2 })
-	end
-	minetest.after(0.1, comparator_turnon , {pos = pos, node = node})
-end
-
-
-local function comparator_deactivate(pos, node)
-	local def = minetest.registered_nodes[node.name]
-	local offstate = def.comparator_offstate
-	if offstate then
-		minetest.swap_node(pos, { name = offstate, param2 = node.param2 })
-	end
-	minetest.after(0.1, comparator_turnoff, {pos = pos, node = node})
-end
-
-
--- weather pos has an inventory that contains at least one item
-local function container_inventory_nonempty(pos)
-	local invnode = minetest.get_node(pos)
-	local invnodedef = minetest.registered_nodes[invnode.name]
-	-- Ignore stale nodes
-	if not invnodedef then return false end
-
-	-- Only accept containers. When a container is dug, it's inventory
-	-- seems to stay. and we don't want to accept the inventory of an air
-	-- block
-	if not invnodedef.groups.container then return false end
-
-	local inv = minetest.get_inventory({type="node", pos=pos})
-	if not inv then return false end
-
-	for listname, _ in pairs(inv:get_lists()) do
-		if not inv:is_empty(listname) then return true end
-	end
-
-	return false
-end
-
--- weather pos has an constant signal output for the comparator
-local function static_signal_output(pos)
-	local node = minetest.get_node(pos)
-	local g = minetest.get_item_group(node.name, "comparator_signal")
-	return g > 0
-end
-
--- whether the comparator should be on according to its inputs
-local function comparator_desired_on(pos, node)
-	local my_input_rules = comparator_get_input_rules(node);
-	local back_rule = my_input_rules[1]
-	local state
-	if back_rule then
-		local back_pos = vector.add(pos, back_rule)
-		state = mesecon.is_power_on(back_pos) or container_inventory_nonempty(back_pos) or static_signal_output(back_pos)
-	end
-
-	-- if back input if off, we don't need to check side inputs
-	if not state then return false end
-
-	-- without power levels, side inputs have no influence on output in compare
-	-- mode
-	local mode = minetest.registered_nodes[node.name].comparator_mode
-	if mode == "comp" then return state end
-
-	-- subtract mode, subtract max(side_inputs) from back input
-	local side_state = false
-	for ri = 2,3 do
-		if my_input_rules[ri] then
-			side_state = mesecon.is_power_on(vector.add(pos, my_input_rules[ri]))
-		end
-		if side_state then break end
-	end
-	-- state is known to be true
-	return not side_state
-end
-
-
+local POSSIBLE_COMPARATOR_POSITIONS = {
+	vector.new( 1,0, 0),
+	vector.new(-1,0, 0),
+	vector.new( 0,0, 1),
+	vector.new( 0,0,-1),
+}
 -- update comparator state, if needed
 local function update_self(pos, node)
 	node = node or minetest.get_node(pos)
-	local old_state = mesecon.is_receptor_on(node.name)
-	local new_state = comparator_desired_on(pos, node)
-	if new_state ~= old_state then
-		if new_state then
-			comparator_activate(pos, node)
-		else
-			comparator_deactivate(pos, node)
+
+	-- Find the node we are pointing at
+	local input_rules = comparator_get_input_rules(node);
+	local back_rule = input_rules[1]
+	local back_pos = vector.add(pos, back_rule)
+	local back_node = minetest.get_node(back_pos)
+	local back_nodedef = minetest.registered_nodes[back_node.name]
+
+	-- Get the comparator mode
+	local mode = minetest.registered_nodes[node.name].comparator_mode
+
+	-- Get a comparator reading from the block at the back of the comparator
+	local power_level = 0
+	if back_nodedef and back_nodedef._mcl_comparators_get_reading then
+		power_level = back_nodedef._mcl_comparators_get_reading(back_pos)
+	end
+
+	-- Get the maximum side power level
+	local side_power_level = 0
+	for i=2,3 do
+		local pl = vl_redstone.get_power_level(vector.add(pos,input_rules[i]))
+		if pl > side_power_level then
+			side_power_level = pl
+		end
+	end
+
+	-- Apply subtraction or comparison
+	if mode == "sub" then
+		power_level = power_level - side_power_level
+		if power_level < 0 then power_level = 0 end
+	elseif mode == "comp" then
+		if side_power_level > power_level then
+			power_level = 0
+		end
+	end
+
+	vl_redstone.set_power(pos, power_level)
+end
+
+function mod.trigger_update(pos)
+	-- try to find a comparator with the back rule leading to pos
+	for i = 1,#POSSIBLE_COMPARATOR_POSITIONS do
+		local candidate = vector.add(pos, POSSIBLE_COMPARATOR_POSITIONS[i])
+		local node = minetest.get_node(candidate)
+		if minetest.get_item_group(node.name,"mcl_comparator") ~= 0 then
+			update_self(candidate, node)
 		end
 	end
 end
 
+function mod.read_inventory(inv, inv_name)
+	local stacks = inv:get_list(inv_name)
+	local count = 0
+	for i=1,#stacks do
+		count = count + ( stacks[i]:get_count() / stacks[i]:get_stack_max() )
+	end
+	return math.floor(count * 16 / 5)
+end
 
 -- compute tile depending on state and mode
 local function get_tiles(state, mode)
@@ -215,6 +172,7 @@ local groups = {
 	destroy_by_lava_flow = 1,
 	dig_by_piston = 1,
 	attached_node = 1,
+	mcl_comparator = 1,
 }
 
 local on_rotate
@@ -309,7 +267,7 @@ for _, mode in pairs{"comp", "sub"} do
 		end
 
 		minetest.register_node(nodename, nodedef)
-		mcl_wip.register_wip_item(nodename)
+		--mcl_wip.register_wip_item(nodename)
 	end
 end
 
@@ -327,6 +285,7 @@ minetest.register_craft({
 	}
 })
 
+--[[
 -- Register active block handlers
 minetest.register_abm({
 	label = "Comparator signal input check (comparator is off)",
@@ -352,7 +311,7 @@ minetest.register_abm({
 	chance = 1,
 	action = update_self,
 })
-
+]]
 
 -- Add entry aliases for the Help
 if minetest.get_modpath("doc") then

mods/ITEMS/REDSTONE/mcl_comparators/mod.conf

@@ -1,3 +1,3 @@
 name = mcl_comparators
-depends = mcl_wip, mesecons, mcl_sounds
+depends = mesecons, mcl_sounds, vl_redstone
 optional_depends = doc, screwdriver

mods/ITEMS/REDSTONE/vl_redstone/init.lua

@@ -4,7 +4,6 @@ vl_redstone = {}
 local mod = vl_redstone
 
 local REDSTONE_POWER_META = modname .. ".power"
-local REDSTONE_POWER_META_LAST_STATE = modname .. ".last-power"
 local REDSTONE_POWER_META_SOURCE = REDSTONE_POWER_META.."."
 
 local function update_sink(pos)
@@ -33,10 +32,10 @@ local function update_sink(pos)
 		end
 	end
 
-	local last_strength = meta:get_int(REDSTONE_POWER_META_LAST_STATE)
+	local last_strength = meta:get_int(REDSTONE_POWER_META)
 
 	if last_strength ~= strength then
-		print("Updating "..node.name.." at "..vector.to_string(pos).."("..tostring(last_strength).."->"..tostring(strength)..")")
+		--print("Updating "..node.name.." at "..vector.to_string(pos).."("..tostring(last_strength).."->"..tostring(strength)..")")
 		-- Inform the node of changes
 		if strength > 0 then
 			-- Handle activation
@@ -54,7 +53,7 @@ local function update_sink(pos)
 		-- TODO: handle signal level change notification
 
 		-- Update the state as the last thing in case there is a crash in the above code
-		meta:set_int(REDSTONE_POWER_META_LAST_STATE, strength)
+		meta:set_int(REDSTONE_POWER_META, strength)
 	end
 end
 
@@ -90,34 +89,35 @@ local function get_positions_from_node_rules(pos, rules_type, list, powered)
 		rules = POWERED_BLOCK_RULES
 	end
 
-	print("rules="..dump(rules))
+	--print("rules="..dump(rules))
 
 	-- Convert to absolute positions
 	for i=1,#rules do
 		local next_pos = vector.add(pos, rules[i])
 		local next_pos_str = vector.to_string(next_pos)
-		print("\tnext: "..next_pos_str..", prev="..tostring(list[next_pos_str]))
+		--print("\tnext: "..next_pos_str..", prev="..tostring(list[next_pos_str]))
 		list[next_pos_str] = true
 
 		-- Power solid blocks
 		if rules[i].spread then
 			powered[next_pos_str] = true
-			print("powering "..next_pos_str)
+			--print("powering "..next_pos_str)
 		end
 	end
 
 	return list
 end
 
-vl_scheduler.register_function("vl_redstone:flow_power",function(task, source_pos, strength, distance)
-	print("Flowing lv"..tostring(strength).." power from "..vector.to_string(source_pos).." for "..tostring(distance).." blocks")
+vl_scheduler.register_function("vl_redstone:flow_power",function(task, source_pos, source_strength, distance)
+	print("Flowing lv"..tostring(source_strength).." power from "..vector.to_string(source_pos).." for "..tostring(distance).." blocks")
 	local processed = {}
 	local powered = {}
 	local source_pos_str = vector.to_string(source_pos)
+	processed[source_pos_str] = true
 
 	-- Update the source node's redstone power
 	local meta = minetest.get_meta(source_pos)
-	meta:set_int(REDSTONE_POWER_META, strength)
+	meta:set_int(REDSTONE_POWER_META, source_strength)
 
 	-- Get rules
 	local list = {}
@@ -126,11 +126,11 @@ vl_scheduler.register_function("vl_redstone:flow_power",function(task, source_po
 
 	for i=1,distance do
 		local next_list = {}
-		local strength = strength - (i - 1)
+		local strength = source_strength - (i - 1)
 		if strength < 0 then strength = 0 end
 
 		for pos_str,dir in pairs(list) do
-			print("Processing "..pos_str)
+			--print("Processing "..pos_str)
 
 			if not processed[pos_str] then
 				processed[pos_str] = true
@@ -140,7 +140,7 @@ vl_scheduler.register_function("vl_redstone:flow_power",function(task, source_po
 
 				-- Update node power directly
 				meta:set_int(REDSTONE_POWER_META.."."..source_pos_str, strength)
-				print("pos="..vector.to_string(pos)..", strength="..tostring(strength))
+				--print("pos="..vector.to_string(pos)..", strength="..tostring(strength))
 
 				-- handle spread
 				get_positions_from_node_rules(pos, "conductor", next_list, powered)
@@ -158,10 +158,23 @@ end)
 function vl_redstone.set_power(pos, strength)
 	local meta = minetest.get_meta(pos)
 	local distance = meta:get_int(REDSTONE_POWER_META)
+
+	-- Don't perform an update if the power level is the same as before
+	if distance == strength then return end
+
+	print("previous="..tostring(distance)..", new="..tostring(strength))
+
+	-- Make the update distance the maximum of the new strength and the old strength
 	if distance < strength then
 		distance = strength
 	end
 
-	vl_scheduler.add_task(0, "vl_redstone:flow_power", 2, {pos, strength, distance})
+	-- Schedule an update
+	vl_scheduler.add_task(0, "vl_redstone:flow_power", 2, {pos, strength, distance + 1})
+end
+
+function vl_redstone.get_power_level(pos)
+	local meta = minetest.get_meta(pos)
+	return meta:get_int(REDSTONE_POWER_META)
 end
 

mods/ITEMS/mcl_hoppers/init.lua

@@ -283,14 +283,17 @@ local def_hopper = {
 		end
 	end,
 	on_metadata_inventory_move = function(pos, from_list, from_index, to_list, to_index, count, player)
+		mcl_comparators.trigger_update(pos)
 		minetest.log("action", player:get_player_name() ..
 			" moves stuff in mcl_hoppers at " .. minetest.pos_to_string(pos))
 	end,
 	on_metadata_inventory_put = function(pos, listname, index, stack, player)
+		mcl_comparators.trigger_update(pos)
 		minetest.log("action", player:get_player_name() ..
 			" moves stuff to mcl_hoppers at " .. minetest.pos_to_string(pos))
 	end,
 	on_metadata_inventory_take = function(pos, listname, index, stack, player)
+		mcl_comparators.trigger_update(pos)
 		minetest.log("action", player:get_player_name() ..
 			" takes stuff from mcl_hoppers at " .. minetest.pos_to_string(pos))
 	end,
@@ -334,6 +337,11 @@ local def_hopper = {
 
 		return true
 	end,
+	_mcl_comparators_get_reading = function (pos)
+		local meta = minetest.get_meta(pos)
+		local inv = meta:get_inventory()
+		return mcl_comparators.read_inventory(inv, "main")
+	end,
 	sounds = mcl_sounds.node_sound_metal_defaults(),
 
 	_mcl_blast_resistance = 4.8,
@@ -525,16 +533,19 @@ local def_hopper_side = {
 		end
 	end,
 	on_metadata_inventory_move = function(pos, from_list, from_index, to_list, to_index, count, player)
+		mcl_comparators.trigger_update(pos)
 		minetest.log("action", player:get_player_name() ..
-			" moves stuff in mcl_hoppers at " .. minetest.pos_to_string(pos))
+			" moves stuff in mcl_hoppers at (1) " .. minetest.pos_to_string(pos))
 	end,
 	on_metadata_inventory_put = function(pos, listname, index, stack, player)
+		mcl_comparators.trigger_update(pos)
 		minetest.log("action", player:get_player_name() ..
-			" moves stuff to mcl_hoppers at " .. minetest.pos_to_string(pos))
+			" moves stuff to mcl_hoppers at (2) " .. minetest.pos_to_string(pos))
 	end,
 	on_metadata_inventory_take = function(pos, listname, index, stack, player)
+		mcl_comparators.trigger_update(pos)
 		minetest.log("action", player:get_player_name() ..
-			" takes stuff from mcl_hoppers at " .. minetest.pos_to_string(pos))
+			" takes stuff from mcl_hoppers at (3) " .. minetest.pos_to_string(pos))
 	end,
 	on_rotate = on_rotate,
 	sounds = mcl_sounds.node_sound_metal_defaults(),

mods/ITEMS/mcl_hoppers/mod.conf

@@ -1,4 +1,4 @@
 name = mcl_hoppers
 description = It's just a clone of Minecraft hoppers, functions nearly identical to them minus mesecons making them stop and the way they're placed.
-depends = mcl_core, mcl_formspec, mcl_sounds, mcl_util, mcl_dye
+depends = mcl_core, mcl_formspec, mcl_sounds, mcl_util, mcl_dye, mcl_comparators
 optional_depends = doc, screwdriver