added license documents

3 files changed, 208 insertions, 626 deletions

diff --git a/license.txt b/license.txt
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--- /dev/null
+++ b/license.txt
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+GNU LESSER GENERAL PUBLIC LICENSE
+
+Version 2.1, February 1999
+
+Copyright (C) 1991, 1999 Free Software Foundation, Inc.
+51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+Everyone is permitted to copy and distribute verbatim copies
+of this license document, but changing it is not allowed.
+
+[This is the first released version of the Lesser GPL.  It also counts
+ as the successor of the GNU Library Public License, version 2, hence
+ the version number 2.1.]
+
+Preamble
+
+The licenses for most software are designed to take away your freedom to share and change it. By contrast, the GNU General Public Licenses are intended to guarantee your freedom to share and change free software--to make sure the software is free for all its users.
+
+This license, the Lesser General Public License, applies to some specially designated software packages--typically libraries--of the Free Software Foundation and other authors who decide to use it. You can use it too, but we suggest you first think carefully about whether this license or the ordinary General Public License is the better strategy to use in any particular case, based on the explanations below.
+
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+Most GNU software, including some libraries, is covered by the ordinary GNU General Public License. This license, the GNU Lesser General Public License, applies to certain designated libraries, and is quite different from the ordinary General Public License. We use this license for certain libraries in order to permit linking those libraries into non-free programs.
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+13. The Free Software Foundation may publish revised and/or new versions of the Lesser General Public License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns.
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+END OF TERMS AND CONDITIONS 
diff --git a/license_media.txt b/license_media.txt
new file mode 100644
index 0000000..66b9d54
--- /dev/null
+++ b/license_media.txt
@@ -0,0 +1,66 @@
+The rails are edited versions of the rails from default minetest_game, also is the gravel texture. All media are licensed under the following license:
+
+CC-BY-SA 3.0 unported
+
+License
+
+THE WORK (AS DEFINED BELOW) IS PROVIDED UNDER THE TERMS OF THIS CREATIVE COMMONS PUBLIC LICENSE ("CCPL" OR "LICENSE"). THE WORK IS PROTECTED BY COPYRIGHT AND/OR OTHER APPLICABLE LAW. ANY USE OF THE WORK OTHER THAN AS AUTHORIZED UNDER THIS LICENSE OR COPYRIGHT LAW IS PROHIBITED.
+
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+
+1. Definitions
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diff --git a/trainlogic.lua~ b/trainlogic.lua~
deleted file mode 100644
index d12dfa2..0000000
--- a/trainlogic.lua~
+++ /dev/null
@@ -1,626 +0,0 @@
---trainlogic.lua
---controls train entities stuff about connecting/disconnecting/colliding trains and other things
-
-local print=function(t) minetest.log("action", t) minetest.chat_send_all(t) end
-
-advtrains.train_accel_force=5--per second and divided by number of wagons
-advtrains.train_brake_force=3--per second, not divided by number of wagons
-advtrains.train_emerg_force=10--for emergency brakes(when going off track)
-
-advtrains.audit_interval=10
-
-advtrains.all_traintypes={}
-function advtrains.register_train_type(name, drives_on, max_speed)
-	advtrains.all_traintypes[name]={}
-	advtrains.all_traintypes[name].drives_on=drives_on
-	advtrains.all_traintypes[name].max_speed=max_speed or 10
-end
-
-
-advtrains.trains={}
-advtrains.wagon_save={}
-
---load initially
-advtrains.fpath=minetest.get_worldpath().."/advtrains"
-local file, err = io.open(advtrains.fpath, "r")
-if not file then
-	local er=err or "Unknown Error"
-	print("[advtrains]Failed loading advtrains save file "..er)
-else
-	local tbl = minetest.deserialize(file:read("*a"))
-	if type(tbl) == "table" then
-		advtrains.trains=tbl
-	end
-	file:close()
-end
-advtrains.fpath_ws=minetest.get_worldpath().."/advtrains_wagon_save"
-local file, err = io.open(advtrains.fpath_ws, "r")
-if not file then
-	local er=err or "Unknown Error"
-	print("[advtrains]Failed loading advtrains save file "..er)
-else
-	local tbl = minetest.deserialize(file:read("*a"))
-	if type(tbl) == "table" then
-		advtrains.wagon_save=tbl
-	end
-	file:close()
-end
-
-
-advtrains.save = function()
-	--print("[advtrains]saving")
-	advtrains.invalidate_all_paths()
-	local datastr = minetest.serialize(advtrains.trains)
-	if not datastr then
-		minetest.log("error", "[advtrains] Failed to serialize train data!")
-		return
-	end
-	local file, err = io.open(advtrains.fpath, "w")
-	if err then
-		return err
-	end
-	file:write(datastr)
-	file:close()
-	
-	-- update wagon saves
-	for _,wagon in pairs(minetest.luaentities) do
-		if wagon.is_wagon and wagon.initialized then
-			advtrains.wagon_save[wagon.unique_id]=advtrains.merge_tables(wagon)--so, will only copy non_metatable elements
-		end
-	end
-	--cross out userdata
-	for w_id, data in pairs(advtrains.wagon_save) do
-		data.name=nil
-		data.object=nil
-		if data.driver then
-			data.driver_name=data.driver:get_player_name()
-			data.driver=nil
-		else
-			data.driver_name=nil
-		end
-	end
-	--print(dump(advtrains.wagon_save))
-	datastr = minetest.serialize(advtrains.wagon_save)
-	if not datastr then
-		minetest.log("error", "[advtrains] Failed to serialize train data!")
-		return
-	end
-	file, err = io.open(advtrains.fpath_ws, "w")
-	if err then
-		return err
-	end
-	file:write(datastr)
-	file:close()
-	
-	advtrains.save_trackdb()
-end
-minetest.register_on_shutdown(advtrains.save)
-
-advtrains.save_and_audit_timer=advtrains.audit_interval
-minetest.register_globalstep(function(dtime)
-	advtrains.save_and_audit_timer=advtrains.save_and_audit_timer-dtime
-	if advtrains.save_and_audit_timer<=0 then
-		--print("[advtrains] audit step")
-		--clean up orphaned trains
-		for k,v in pairs(advtrains.trains) do
-			--advtrains.update_trainpart_properties(k)
-			if #v.trainparts==0 then
-				advtrains.trains[k]=nil
-			end
-		end
-		--save
-		advtrains.save()
-		advtrains.save_and_audit_timer=advtrains.audit_interval
-	end
-	--regular train step
-	for k,v in pairs(advtrains.trains) do
-		advtrains.train_step(k, v, dtime)
-	end
-end)
-
-function advtrains.train_step(id, train, dtime)
-	
-	--TODO check for all vars to be present
-	
-	--if not train.last_pos then advtrains.trains[id]=nil return end
-	
-	if not advtrains.pathpredict(id, train) then 
-		print("pathpredict failed(returned false)")
-		train.velocity=0
-		train.tarvelocity=0
-		return
-	end
-	
-	local path=advtrains.get_or_create_path(id, train)
-	if not path then
-		train.velocity=0
-		train.tarvelocity=0
-		print("train has no path for whatever reason")
-		return 
-	end
-	--apply off-track handling:
-	local front_off_track=train.max_index_on_track and train.index>train.max_index_on_track
-	local back_off_track=train.min_index_on_track and (train.index-train.trainlen)<train.min_index_on_track
-	if front_off_track and back_off_track then--allow movement in both directions
-		if train.tarvelocity>1 then train.tarvelocity=1 end
-		if train.tarvelocity<-1 then train.tarvelocity=-1 end
-	elseif front_off_track then--allow movement only backward
-		if train.tarvelocity>0 then train.tarvelocity=0 end
-		if train.tarvelocity<-1 then train.tarvelocity=-1 end
-	elseif back_off_track then--allow movement only forward
-		if train.tarvelocity>1 then train.tarvelocity=1 end
-		if train.tarvelocity<0 then train.tarvelocity=0 end
-	end
-	
-	--move
-	if not train.velocity then
-		train.velocity=0
-	end
-	train.index=train.index and train.index+((train.velocity/(train.path_dist[math.floor(train.index)] or 1))*dtime) or 0
-	--check for collisions by finding objects
-	--front
-	local search_radius=4
-	
-	local posfront=path[math.floor(train.index+1)]
-	if posfront then
-		local objrefs=minetest.get_objects_inside_radius(posfront, search_radius)
-		for _,v in pairs(objrefs) do
-			local le=v:get_luaentity()
-			if le and le.is_wagon and le.initialized and le.train_id~=id then
-				advtrains.try_connect_trains(id, le.train_id)
-			end
-		end
-	end
-	local posback=path[math.floor(train.index-(train.trainlen or 0)-1)]
-	if posback then
-		local objrefs=minetest.get_objects_inside_radius(posback, search_radius)
-		for _,v in pairs(objrefs) do
-			local le=v:get_luaentity()
-			if le and le.is_wagon and le.initialized and le.train_id~=id then
-				advtrains.try_connect_trains(id, le.train_id)
-			end
-		end
-	end
-	
-	--check for any trainpart entities if they have been unloaded. do this only if train is near a player, to not spawn entities into unloaded areas
-	train.check_trainpartload=(train.check_trainpartload or 0)-dtime
-	local node_range=(math.max((minetest.setting_get("active_block_range") or 0),1)*16)
-	if train.check_trainpartload<=0 and posfront and posback then
-		print(minetest.pos_to_string(posfront))
-		local should_check=false
-		for _,p in ipairs(minetest.get_connected_players()) do
-			should_check=should_check or ((vector.distance(posfront, p:getpos())<node_range) and (vector.distance(posback, p:getpos())<node_range))
-		end
-		if should_check then
-			--it is better to iterate luaentites only once
-			print("check_trainpartload")
-			local found_uids={}
-			for _,wagon in pairs(minetest.luaentities) do
-				if wagon.is_wagon and wagon.initialized and wagon.train_id==id then
-					if found_uids[wagon.unique_id] then
-						--duplicate found, delete it
-						if wagon.object then wagon.object:remove() end
-					else
-						found_uids[wagon.unique_id]=true
-					end
-				end
-			end
-			print("found_uids: "..dump(found_uids))
-			--now iterate trainparts and check. then cross them out to see if there are wagons over for any reason
-			for pit, w_id in ipairs(train.trainparts) do
-				if found_uids[w_id] then
-					print(w_id.." still loaded")
-				elseif advtrains.wagon_save[w_id] then
-					print(w_id.." not loaded, but save available")
-					--spawn a new and initialize it with the properties from wagon_save
-					local le=minetest.env:add_entity(posfront, advtrains.wagon_save[w_id].entity_name):get_luaentity()
-					for k,v in pairs(advtrains.wagon_save[w_id]) do
-						le[k]=v
-					end
-					advtrains.wagon_save[w_id].name=nil
-					advtrains.wagon_save[w_id].object=nil
-				else
-					print(w_id.." not loaded and no save available")
-					--what the hell...
-					table.remove(train.trainparts, pit)
-				end
-			end
-		end
-		train.check_trainpartload=1
-	end
-	
-	
-	--handle collided_with_env
-	if train.recently_collided_with_env then
-		train.tarvelocity=0
-		if train.velocity==0 then
-			train.recently_collided_with_env=false--reset status when stopped
-		end
-	end
-	if train.locomotives_in_train==0 then
-		train.tarvelocity=0
-	end
-	--apply tarvel(but with physics in mind!)
-	if train.velocity~=train.tarvelocity then
-		local applydiff=0
-		local mass=#train.trainparts
-		local diff=math.abs(train.tarvelocity)-math.abs(train.velocity)
-		if diff>0 then--accelerating, force will be brought on only by locomotives.
-			--print("accelerating with default force")
-			applydiff=(math.min((advtrains.train_accel_force*train.locomotives_in_train*dtime)/mass, math.abs(diff)))
-		else--decelerating
-			if front_off_track or back_off_track or train.recently_collided_with_env then --every wagon has a brake, so not divided by mass.
-				--print("braking with emergency force")
-				applydiff=(math.min((advtrains.train_emerg_force*dtime), math.abs(diff)))
-			else
-				--print("braking with default force")
-				applydiff=(math.min((advtrains.train_brake_force*dtime), math.abs(diff)))
-			end
-		end
-		train.velocity=train.velocity+(applydiff*math.sign(train.tarvelocity-train.velocity))
-	end
-	
-end
-
---the 'leader' concept has been overthrown, we won't rely on MT's "buggy object management"
---structure of train table:
---[[
-trains={
-	[train_id]={
-		trainparts={
-			[n]=wagon_id
-		}
-		path={path}
-		velocity
-		tarvelocity
-		index
-		trainlen
-		path_inv_level
-		last_pos       |
-		last_dir       | for pathpredicting.
-		no_connect_for_movements (index way counter for when not to connect again) TODO implement
-	}
-}
---a wagon itself has the following properties:
-wagon={
-	unique_id
-	train_id
-	pos_in_train (is index difference, including train_span stuff)
-	pos_in_trainparts (is index in trainparts tabel of trains)
-}
-inherited by metatable:
-wagon_proto={
-	wagon_span
-}
-]]
-
---returns new id
-function advtrains.create_new_train_at(pos, pos_prev, traintype)
-	local newtrain_id=os.time()..os.clock()
-	while advtrains.trains[newtrain_id] do newtrain_id=os.time()..os.clock() end--ensure uniqueness(will be unneccessary)
-	
-	advtrains.trains[newtrain_id]={}
-	advtrains.trains[newtrain_id].last_pos=pos
-	advtrains.trains[newtrain_id].last_pos_prev=pos_prev
-	advtrains.trains[newtrain_id].traintype=traintype
-	advtrains.trains[newtrain_id].tarvelocity=0
-	advtrains.trains[newtrain_id].velocity=0
-	advtrains.trains[newtrain_id].trainparts={}
-	return newtrain_id
-end
-
---returns false on failure. handle this case!
-function advtrains.pathpredict(id, train)
-	
-	--print("pos ",x,y,z)
-	--::rerun::
-	if not train.index then train.index=0 end
-	if not train.path or #train.path<2 then
-		if not train.last_pos then
-			--no chance to recover
-			print("[advtrains]train hasn't saved last-pos, removing train.")
-			advtrains.train[id]=nil
-			return false
-		end
-		
-		local node_ok=advtrains.get_rail_info_at(advtrains.round_vector_floor_y(train.last_pos), train.traintype)
-		
-		if node_ok==nil then
-			--block not loaded, do nothing
-			return nil
-		elseif node_ok==false then
-			print("[advtrains]no track here, (fail) removing train.")
-			advtrains.trains[id]=nil
-			return false
-		end
-		
-		if not train.last_pos_prev then
-			--no chance to recover
-			print("[advtrains]train hasn't saved last-pos_prev, removing train.")
-			advtrains.trains[id]=nil
-			return false
-		end
-		
-		local prevnode_ok=advtrains.get_rail_info_at(advtrains.round_vector_floor_y(train.last_pos_prev), train.traintype)
-		
-		if prevnode_ok==nil then
-			--block not loaded, do nothing
-			return nil
-		elseif prevnode_ok==false then
-			print("[advtrains]no track at prev, (fail) removing train.")
-			advtrains.trains[id]=nil
-			return false
-		end
-		
-		train.index=(train.restore_add_index or 0)+(train.savedpos_off_track_index_offset or 0)
-		--restore_add_index is set by save() to prevent trains hopping to next round index. should be between -0.5 and 0.5
-		--savedpos_off_track_index_offset is set if train went off track. see below.
-		train.path={}
-		train.path_dist={}
-		train.path[0]=train.last_pos
-		train.path[-1]=train.last_pos_prev
-		train.path_dist[-1]=vector.distance(train.last_pos, train.last_pos_prev)
-	end
-	
-	local maxn=advtrains.maxN(train.path)
-	while (maxn-train.index) < 2 do--pregenerate
-		--print("[advtrains]maxn conway for ",maxn,minetest.pos_to_string(path[maxn]),maxn-1,minetest.pos_to_string(path[maxn-1]))
-		local conway=advtrains.conway(train.path[maxn], train.path[maxn-1], train.traintype)
-		if conway then
-			train.path[maxn+1]=conway
-			train.max_index_on_track=maxn
-		else
-			--do as if nothing has happened and preceed with path
-			--but do not update max_index_on_track
-			print("over-generating path max to index "..maxn+1)
-			train.path[maxn+1]=vector.add(train.path[maxn], vector.subtract(train.path[maxn], train.path[maxn-1]))
-		end
-		train.path_dist[maxn]=vector.distance(train.path[maxn+1], train.path[maxn])
-		maxn=advtrains.maxN(train.path)
-	end
-	
-	local minn=advtrains.minN(train.path)
-	while (train.index-minn) < (train.trainlen or 0) + 2 do --post_generate. has to be at least trainlen.
-		--print("[advtrains]minn conway for ",minn,minetest.pos_to_string(path[minn]),minn+1,minetest.pos_to_string(path[minn+1]))
-		local conway=advtrains.conway(train.path[minn], train.path[minn+1], train.traintype)
-		if conway then
-			train.path[minn-1]=conway
-			train.min_index_on_track=minn
-		else
-			--do as if nothing has happened and preceed with path
-			--but do not update min_index_on_track
-			print("over-generating path min to index "..minn-1)
-			train.path[minn-1]=vector.add(train.path[minn], vector.subtract(train.path[minn], train.path[minn+1]))
-		end
-		train.path_dist[minn-1]=vector.distance(train.path[minn], train.path[minn-1])
-		minn=advtrains.minN(train.path)
-	end
-	if not train.min_index_on_track then train.min_index_on_track=0 end
-	if not train.max_index_on_track then train.max_index_on_track=0 end
-	
-	--make pos/yaw available for possible recover calls
-	if train.max_index_on_track<train.index then --whoops, train went too far. the saved position will be the last one that lies on a track, and savedpos_off_track_index_offset will hold how far to go from here
-		train.savedpos_off_track_index_offset=train.index-train.max_index_on_track
-		train.last_pos=train.path[train.max_index_on_track]
-		train.last_pos_prev=train.path[train.max_index_on_track-1]
-		--print("train is off-track (front), last positions kept at "..minetest.pos_to_string(train.last_pos).." / "..minetest.pos_to_string(train.last_pos_prev))
-	elseif train.min_index_on_track+1>train.index then --whoops, train went even more far. same behavior
-		train.savedpos_off_track_index_offset=train.index-train.min_index_on_track
-		train.last_pos=train.path[train.min_index_on_track+1]
-		train.last_pos_prev=train.path[train.min_index_on_track]
-		--print("train is off-track (back), last positions kept at "..minetest.pos_to_string(train.last_pos).." / "..minetest.pos_to_string(train.last_pos_prev))
-	else --regular case
-		train.savedpos_off_track_index_offset=nil
-		train.last_pos=train.path[math.floor(train.index+0.5)]
-		train.last_pos_prev=train.path[math.floor(train.index-0.5)]
-	end
-	return train.path
-end
-
-function advtrains.get_or_create_path(id, train)
-	if not train.path then return advtrains.pathpredict(id, train) end
-	
-	return train.path
-end
-
-function advtrains.add_wagon_to_train(wagon, train_id, index)
-	local train=advtrains.trains[train_id]
-	if index then
-		table.insert(train.trainparts, index, wagon.unique_id)
-	else
-		table.insert(train.trainparts, wagon.unique_id)
-	end
-	--this is not the usual case!!!
-	--we may set initialized because the wagon has no chance to step()
-	wagon.initialized=true
-	advtrains.update_trainpart_properties(train_id)
-end
-function advtrains.update_trainpart_properties(train_id, invert_flipstate)
-	local train=advtrains.trains[train_id]
-	local rel_pos=0
-	local count_l=0
-	for i, w_id in ipairs(train.trainparts) do
-		local any_loaded=false
-		for _,wagon in pairs(minetest.luaentities) do
-			if wagon.is_wagon and wagon.initialized and wagon.unique_id==w_id then
-				rel_pos=rel_pos+wagon.wagon_span
-				wagon.train_id=train_id
-				wagon.pos_in_train=rel_pos
-				wagon.pos_in_trainparts=i
-				wagon.old_velocity_vector=nil
-				if wagon.is_locomotive then
-					count_l=count_l+1
-				end
-				if invert_flipstate then
-					wagon.wagon_flipped = not wagon.wagon_flipped
-				end
-				rel_pos=rel_pos+wagon.wagon_span
-				any_loaded=true
-			end
-		end
-		if not any_loaded then
-			print("update_trainpart_properties wagon "..w_id.." not loaded, ignoring it.")
-		end
-	end
-	train.trainlen=rel_pos
-	train.locomotives_in_train=count_l
-end
-
-function advtrains.split_train_at_wagon(wagon)
-	--get train
-	local train=advtrains.trains[wagon.train_id]
-	local pos_for_new_train=advtrains.get_or_create_path(wagon.train_id, train)[math.floor((train.index or 0)-wagon.pos_in_train-0.5)]
-	local pos_for_new_train_prev=advtrains.get_or_create_path(wagon.train_id, train)[math.floor((train.index or 0)-wagon.pos_in_train-1.5)]
-	
-	--before doing anything, check if both are rails. else do not allow
-	if not pos_for_new_train then
-		print("split_train: pos_for_new_train not set")
-		return false
-	end
-	local node_ok=advtrains.get_rail_info_at(advtrains.round_vector_floor_y(pos_for_new_train), train.traintype)
-	if not node_ok then
-		print("split_train: pos_for_new_train "..minetest.pos_to_string(advtrains.round_vector_floor_y(pos_for_new_train_prev)).." not loaded or is not a rail")
-		return false
-	end
-	
-	if not train.last_pos_prev then
-		print("split_train: pos_for_new_train_prev not set")
-		return false
-	end
-	
-	local prevnode_ok=advtrains.get_rail_info_at(advtrains.round_vector_floor_y(pos_for_new_train), train.traintype)
-	if not prevnode_ok then
-		print("split_train: pos_for_new_train_prev "..minetest.pos_to_string(advtrains.round_vector_floor_y(pos_for_new_train_prev)).." not loaded or is not a rail")
-		return false
-	end
-	
-	--create subtrain
-	local newtrain_id=advtrains.create_new_train_at(pos_for_new_train, pos_for_new_train_prev, train.traintype)
-	local newtrain=advtrains.trains[newtrain_id]
-	--insert all wagons to new train
-	for k,v in ipairs(train.trainparts) do
-		if k>=wagon.pos_in_trainparts then
-			table.insert(newtrain.trainparts, v)
-			train.trainparts[k]=nil
-		end
-	end
-	--update train parts
-	advtrains.update_trainpart_properties(wagon.train_id)--atm it still is the desierd id.
-	advtrains.update_trainpart_properties(newtrain_id)
-	train.tarvelocity=0
-	newtrain.velocity=train.velocity
-	newtrain.tarvelocity=0
-end
-
---there are 4 cases:
---1/2. F<->R F<->R regular, put second train behind first
---->frontpos of first train will match backpos of second
---3.   F<->R R<->F flip one of these trains, take the other as new train
---->backpos's will match
---4.   R<->F F<->R flip one of these trains and take it as new parent
---->frontpos's will match
-function advtrains.try_connect_trains(id1, id2)
-	local train1=advtrains.trains[id1]
-	local train2=advtrains.trains[id2]
-	if not train1 or not train2 then return end
-	if not train1.path or not train2.path then return end
-	if train1.traintype~=train2.traintype then
-		--TODO implement collision without connection
-		return
-	end
-	if #train1.trainparts==0 or #train2.trainparts==0 then return end
-	
-	local frontpos1=train1.path[math.floor(train1.index+0.5)]
-	local backpos1=train1.path[math.floor(train1.index-(train1.trainlen or 2)+0.5)]
-	local frontpos2=train2.path[math.floor(train2.index+0.5)]
-	local backpos2=train2.path[math.floor(train2.index-(train1.trainlen or 2)+0.5)]
-	
-	if not frontpos1 or not frontpos2 or not backpos1 or not backpos2 then return end
-	
-	--case 1 (first train is front)
-	if vector.equals(frontpos2, backpos1) then
-		advtrains.do_connect_trains(id1, id2)
-	--case 2 (second train is front)
-	elseif vector.equals(frontpos1, backpos2) then
-		advtrains.do_connect_trains(id2, id1)
-	--case 3 
-	elseif vector.equals(backpos2, backpos1) then
-		advtrains.invert_train(id2)
-		advtrains.do_connect_trains(id1, id2)
-	--case 4 
-	elseif vector.equals(frontpos2, frontpos1) then
-		advtrains.invert_train(id1)
-		advtrains.do_connect_trains(id1, id2)
-	end
-end
-function advtrains.do_connect_trains(first_id, second_id)
-	local first_wagoncnt=#advtrains.trains[first_id].trainparts
-	local second_wagoncnt=#advtrains.trains[second_id].trainparts
-	
-	for _,v in ipairs(advtrains.trains[second_id].trainparts) do
-		table.insert(advtrains.trains[first_id].trainparts, v)
-	end
-	--kick it like physics (with mass being #wagons)
-	local new_velocity=((advtrains.trains[first_id].velocity*first_wagoncnt)+(advtrains.trains[second_id].velocity*second_wagoncnt))/(first_wagoncnt+second_wagoncnt)
-	advtrains.trains[second_id]=nil
-	advtrains.update_trainpart_properties(first_id)
-	advtrains.trains[first_id].velocity=new_velocity
-	advtrains.trains[first_id].tarvelocity=0
-end
-
-function advtrains.invert_train(train_id)
-	local train=advtrains.trains[train_id]
-	
-	local old_path=advtrains.get_or_create_path(train_id, train)
-	train.path={}
-	train.index=-train.index+train.trainlen
-	train.velocity=-train.velocity
-	train.tarvelocity=-train.tarvelocity
-	for k,v in pairs(old_path) do
-		train.path[-k]=v
-	end
-	local old_trainparts=train.trainparts
-	train.trainparts={}
-	for k,v in ipairs(old_trainparts) do
-		table.insert(train.trainparts, 1, v)--notice insertion at first place
-	end
-	advtrains.update_trainpart_properties(train_id, true)
-end
-
-function advtrains.is_train_at_pos(pos)
-	--print("istrainat: pos "..minetest.pos_to_string(pos))
-	local checked_trains={}
-	local objrefs=minetest.get_objects_inside_radius(pos, 2)
-	for _,v in pairs(objrefs) do
-		local le=v:get_luaentity()
-		if le and le.is_wagon and le.initialized and le.train_id and not checked_trains[le.train_id] then
-			--print("istrainat: checking "..le.train_id)
-			checked_trains[le.train_id]=true
-			local path=advtrains.get_or_create_path(le.train_id, le:train())
-			if path then
-				--print("has path")
-				for i=math.floor(le:train().index-le:train().trainlen+0.5),math.floor(le:train().index+0.5) do
-					if path[i] then
-						--print("has pathitem "..i.." "..minetest.pos_to_string(path[i]))
-						if vector.equals(advtrains.round_vector_floor_y(path[i]), pos) then
-							return true
-						end
-					end
-				end
-			end
-		end
-	end
-	return false
-end
-function advtrains.invalidate_all_paths()
-	--print("invalidating all paths")
-	for k,v in pairs(advtrains.trains) do
-		if v.index then
-			v.restore_add_index=v.index-math.floor(v.index+0.5)
-		end
-		v.path=nil
-		v.index=nil
-		v.min_index_on_track=nil
-		v.max_index_on_track=nil
-	end
-end
\ No newline at end of file