Skeleton support for Techage Liquids in tank cars

TODO:
- Pretty nodes for loader and unloader
- Display liquid contents in formspec
- Update basic_trains accordingly

4 files changed, 237 insertions, 3 deletions

diff --git a/advtrains/init.lua b/advtrains/init.lua
index a7e5764..a2c2def 100644
--- a/advtrains/init.lua
+++ b/advtrains/init.lua
@@ -222,10 +222,12 @@ dofile(advtrains.modpath.."/craft_items.lua")
 
 dofile(advtrains.modpath.."/log.lua")
 dofile(advtrains.modpath.."/passive.lua")
-if mesecon then
+if minetest.global_exists("mesecon") then
 	dofile(advtrains.modpath.."/p_mesecon_iface.lua")
 end
-
+if minetest.global_exists("techage") then
+	dofile(advtrains.modpath.."/techage.lua")
+end
 
 dofile(advtrains.modpath.."/lzb.lua")
 
diff --git a/advtrains/mod.conf b/advtrains/mod.conf
index 5808d1a..597a642 100644
--- a/advtrains/mod.conf
+++ b/advtrains/mod.conf
@@ -4,4 +4,4 @@ description=Core system for realistic trains in Minetest
 author=orwell96
 
 depends=serialize_lib
-optional_depends=mesecons,mesecons_switch,digtron
+optional_depends=mesecons,mesecons_switch,digtron,techage
diff --git a/advtrains/techage.lua b/advtrains/techage.lua
new file mode 100644
index 0000000..abd5987
--- /dev/null
+++ b/advtrains/techage.lua
@@ -0,0 +1,227 @@
+-- techage.lua

+-- Tech-age specific features, loaded only when techage is found

+

+-- == Liquid features == --

+-- Tank wagons can get support for Techage liquids.

+-- advtrains provides a "Tank car filling spigot" and a "Tank car unloading funnel" which are placed above resp. below the tracks.

+-- They act as proxy nodes from/to which liquids can be pumped using the Techage pumps

+-- Note: for tank cars to support filling with liquid, add the "techage_liquid_capacity = <capacity_in_liquid_units>" property to the wagon definition.

+

+-- Get Techage variables

+local Pipe = techage.LiquidPipe

+local liquid = networks.liquid

+

+-- Nodes

+

+

+-- checks for and gets a tank car at given reference position. Ref Pos must be the track this node relates to.

+-- For a wagon to be valid it must be standing at the node in question

+-- If found, returns liquid_info, capacity, wagon_id (where liquid_info is {name=..., amount=...} in same format as the techage tank nvms)

+-- If not found, returns nil

+local function get_tank_car_liquidinfo(ref_pos)

+	local trains = advtrains.occ.get_trains_at(ref_pos)

+	for train_id, index in pairs(trains) do

+		local train = advtrains.trains[train_id]

+		-- make sure that the train is stopped

+		if train.velocity == 0 then

+			local wagon_num, wid, data, offset_from_center = advtrains.get_wagon_at_index(train_id, index)

+			if wagon_num and offset_from_center < 1 then

+				-- this wagon is possibly a tank car. Check the wagon def

+				local _, proto = advtrains.get_wagon_prototype(data)

+				if proto.techage_liquid_capacity then

+					-- Found a tank car. Get its liquid info from the data table, create it if necessary

+					if not data.techage_liquid then

+						data.techage_liquid = {}

+					end

+					return data.techage_liquid, proto.techage_liquid_capacity, wid

+				end

+			end

+		end

+	end

+	return nil

+end

+

+local function loader_relpos(pos)

+	return {x=pos.x, y=pos.y-3, z=pos.z}

+end

+

+local function tankcar_put_liquid(pos, name, amount)

+	local lic, capa, wid = get_tank_car_liquidinfo(pos)

+	if lic then

+		if lic.name then

+			if lic.name ~= name then

+				-- different liquid than already in here - deny

+				return amount

+			end

+			-- else add the amount

+			lic.amount = lic.amount + amount

+		else

+			-- does not contain liquid yet, set name and amount to 0

+			lic.name = name

+			lic.amount = amount

+		end

+		--atdebug("tankcar_put_liquid: put",name,amount,", now contains ",lic)

+		if lic.amount > capa then

+			-- capacity was hit, reject too much liquid

+			local reject = lic.amount - capa

+			lic.amount = capa

+			--atdebug("tankcar_put_liquid: over capa", capa, ", rejects ", reject)

+			return reject

+		end

+		return 0

+	end

+	return amount

+end

+

+

+local function unloader_relpos(pos)

+	return {x=pos.x, y=pos.y+1, z=pos.z}

+end

+

+local function tankcar_take_liquid(pos, name, amount)

+	local lic, capa, wid = get_tank_car_liquidinfo(pos)

+	if lic then

+		if lic.name then

+			-- note: name parameter may be nil (aka any), then do not prevent

+			if name and lic.name ~= name then

+				-- different liquid than already in here - deny

+				return 0

+			end

+		else

+			-- does not contain liquid, nothing to take

+			return 0

+		end

+		if lic.amount <= amount then

+			-- pumping last bit of liquid

+			local rest, oldname = lic.amount, lic.name

+			lic.amount = 0

+			lic.name = nil -- reset the name since car is now empty

+			--atdebug("tankcar_take_liquid: took",name,amount,", now empty")

+			return rest, oldname

+		end

+		-- no underflow, subtract

+		lic.amount = lic.amount - amount

+		--atdebug("tankcar_take_liquid: took",name,amount,", now left ",lic)

+		return amount, lic.name

+	end

+	return 0 -- no wagon here

+end

+

+minetest.register_node("advtrains:ta_liquid_loader", {

+	description = attrans("Tank Car Filling Spigot"),

+	tiles = {

+		"techage_gaspipe_knee2.png",

+		"techage_gaspipe_hole2.png^[transformR180",

+		"techage_gaspipe_knee.png^[transformR270",

+		"techage_gaspipe_knee.png",

+		"techage_gaspipe_knee2.png",

+		"techage_gaspipe_hole2.png",

+	},

+

+	after_dig_node = function(pos, oldnode, oldmetadata, digger)

+		Pipe:after_dig_tube(pos, oldnode, oldmetadata)

+	end,

+

+	paramtype2 = "facedir", -- important!

+	drawtype = "nodebox",

+	node_box = {

+		type = "fixed",

+		fixed = {

+			{-1/8, -4/8, -1/8, 1/8, 1/8,    1/8},

+			{-2/8, -0.5, -2/8, 2/8, -13/32, 2/8},

+			{-1/8, -1/8, -4/8, 1/8, 1/8,    -1/8},

+			{-2/8, -2/8, -0.5, 2/8, 2/8,    -13/32},

+		},

+	},

+	on_rotate = screwdriver.disallow, -- important!

+	paramtype = "light",

+	use_texture_alpha = techage.CLIP,

+	sunlight_propagates = true,

+	is_ground_content = false,

+	groups = {crumbly = 2, cracky = 2, snappy = 2},

+	sounds = default.node_sound_metal_defaults(),

+	drop = "advtrains:ta_liquid_loader",

+})

+

+liquid.register_nodes({"advtrains:ta_liquid_loader"},

+	Pipe, "tank", nil, {

+		capa = 42, -- should provide the type of liquid anyway, because pump uses it to check whether it can pump here

+		peek = function(pos, indir)

+			local lic, capa, wid = get_tank_car_liquidinfo(loader_relpos(pos))

+			--atdebug("loader peeked: ", lic, capa)

+			if lic and lic.name and lic.amount > 0 then

+				return lic.name

+			end

+			return nil

+		end,

+		put = function(pos, indir, name, amount)

+			return tankcar_put_liquid(loader_relpos(pos), name, amount)

+		end,

+		take = function(pos, indir, name, amount)

+			return 0 -- cannot take anything from the loader

+		end,

+		untake = function(pos, indir, name, amount)

+			return tankcar_put_liquid(loader_relpos(pos), name, amount)

+		end,

+	}

+)

+

+minetest.register_node("advtrains:ta_liquid_unloader", {

+	description = attrans("Tank Car Unloading Drain Funnel"),

+	tiles = {

+		"techage_gaspipe_knee2.png",

+		"techage_gaspipe_hole2.png^[transformR180",

+		"techage_gaspipe_knee.png^[transformR270",

+		"techage_gaspipe_knee.png",

+		"techage_gaspipe_knee2.png",

+		"techage_gaspipe_hole2.png",

+	},

+

+	after_dig_node = function(pos, oldnode, oldmetadata, digger)

+		Pipe:after_dig_tube(pos, oldnode, oldmetadata)

+	end,

+

+	paramtype2 = "facedir", -- important!

+	drawtype = "nodebox",

+	node_box = {

+		type = "fixed",

+		fixed = {

+			{-1/8, -4/8, -1/8, 1/8, 1/8,    1/8},

+			{-2/8, -0.5, -2/8, 2/8, -13/32, 2/8},

+			{-1/8, -1/8, -4/8, 1/8, 1/8,    -1/8},

+			{-2/8, -2/8, -0.5, 2/8, 2/8,    -13/32},

+		},

+	},

+	on_rotate = screwdriver.disallow, -- important!

+	paramtype = "light",

+	use_texture_alpha = techage.CLIP,

+	sunlight_propagates = true,

+	is_ground_content = false,

+	groups = {crumbly = 2, cracky = 2, snappy = 2},

+	sounds = default.node_sound_metal_defaults(),

+	drop = "advtrains:ta_liquid_unloader",

+})

+

+liquid.register_nodes({"advtrains:ta_liquid_unloader"},

+	Pipe, "tank", nil, {

+		capa = 42, -- should be ignored, lets see if it really is

+		peek = function(pos, indir)

+			local lic, capa, wid = get_tank_car_liquidinfo(unloader_relpos(pos))

+			--atdebug("unloader peeked: ", lic, capa)

+			if lic and lic.name and lic.amount > 0 then

+				return lic.name

+			end

+			return nil

+		end,

+		put = function(pos, indir, name, amount)

+			return amount -- cannot put here

+		end,

+		take = function(pos, indir, name, amount)

+			return tankcar_take_liquid(unloader_relpos(pos), name, amount)

+		end,

+		untake = function(pos, indir, name, amount)

+			-- untake has to work like a put would!

+			return tankcar_put_liquid(loader_relpos(pos), name, amount)

+		end,

+	}

+)
\ No newline at end of file
diff --git a/advtrains/wagons.lua b/advtrains/wagons.lua
index b0fb575..d1812aa 100644
--- a/advtrains/wagons.lua
+++ b/advtrains/wagons.lua
@@ -364,6 +364,11 @@ function wagon:on_step(dtime)
 			outside = outside .."\n!!! Train off track !!!"
 		end
 		
+		-- liquid container (temporary solution): display liquid contents in infotext
+		if self.techage_liquid_capacity and data.techage_liquid and data.techage_liquid.name then
+			outside = outside .."\nLiquid: "..data.techage_liquid.name..", "..data.techage_liquid.amount.." units"
+		end
+		
 		if self.infotext_cache~=outside  then
 			self.object:set_properties({infotext=outside})
 			self.infotext_cache=outside