Performance improvements: Don't clear paths unless absolutely necessary

instead delete path elements that are too far from the train one-by-one
Also when switching a switch or changing rails, only clear train paths of trains that are nearby.

advtrains/advtrains/atc.lua

@@ -93,7 +93,7 @@ advtrains.register_tracks("default", {
 			after_place_node=apn_func,
 			after_dig_node=function(pos)
 				return advtrains.pcall(function()
-					advtrains.invalidate_all_paths()
+					advtrains.invalidate_all_paths(pos)
 					advtrains.ndb.clear(pos)
 					local pts=minetest.pos_to_string(pos)
 					atc.controllers[pts]=nil

advtrains/advtrains/init.lua

@@ -37,7 +37,7 @@ advtrains.modpath = minetest.get_modpath("advtrains")
 function advtrains.print_concat_table(a)
 	local str=""
 	local stra=""
-	for i=1,50 do
+	for i=1,10 do
 		t=a[i]
 		if t==nil then
 			stra=stra.."nil "
@@ -67,9 +67,12 @@ end
 atprint=function() end
 if minetest.setting_getbool("advtrains_debug") then
 	atprint=function(t, ...)
+		local context=advtrains.atprint_context_tid
+		if not context then context="" end
+		--if context~="4527" then return end
 		local text=advtrains.print_concat_table({t, ...})
-		minetest.log("action", "[advtrains]"..text)
-		minetest.chat_send_all("[advtrains]"..text)
+		minetest.log("action", "[advtrains]"..context..">"..text)
+		minetest.chat_send_all("[advtrains]"..context..">"..text)
 	end
 end
 atwarn=function(t, ...)
@@ -171,7 +174,8 @@ end
 
 advtrains.avt_save = function()
 	--atprint("saving")
-	advtrains.invalidate_all_paths()
+	--No more invalidating.
+	--Instead, remove path a.s.o from the saved table manually
 	
 	-- update wagon saves
 	for _,wagon in pairs(minetest.luaentities) do
@@ -195,10 +199,34 @@ advtrains.avt_save = function()
 		end
 	end
 	
+	local tmp_trains={}
+	for id, train in pairs(advtrains.trains) do
+		--first, deep_copy the train
+		local v=advtrains.merge_tables(train)
+		--then invalidate
+		if v.index then
+			v.restore_add_index=v.index-math.floor(v.index+0.5)
+		end
+		v.path=nil
+		v.path_dist=nil
+		v.index=nil
+		v.end_index=nil
+		v.min_index_on_track=nil
+		v.max_index_on_track=nil
+		v.path_extent_min=nil
+		v.path_extent_max=nil
+		
+		v.detector_old_index=nil
+		v.detector_old_end_index=nil
+		
+		--then save it
+		tmp_trains[id]=v
+	end
+	
 	--versions:
 	-- 1 - Initial new save format.
 	local save_tbl={
-		trains = advtrains.trains,
+		trains = tmp_trains,
 		wagon_save = advtrains.wagon_save,
 		ptmap = advtrains.player_to_train_mapping,
 		atc = advtrains.atc.save_data(),

advtrains/advtrains/tracks.lua

@@ -263,13 +263,13 @@ function advtrains.register_tracks(tracktype, def, preset)
 		local rcswitchfunc=function(pos, node, player)
 			if minetest.check_player_privs(player:get_player_name(), {train_operator=true}) then
 				advtrains.ndb.swap_node(pos, {name=def.nodename_prefix.."_"..suffix_target, param2=node.param2})
-				advtrains.invalidate_all_paths()
+				advtrains.invalidate_all_paths(pos)
 			end
 		end
 		local switchfunc=function(pos, node, newstate)
 			if newstate~=is_state then
 				advtrains.ndb.swap_node(pos, {name=def.nodename_prefix.."_"..suffix_target, param2=node.param2})
-				advtrains.invalidate_all_paths()
+				advtrains.invalidate_all_paths(pos)
 			end
 		end
 		local mesec

advtrains/advtrains/trainlogic.lua

@@ -55,12 +55,16 @@ advtrains.mainloop_trainlogic=function(dtime)
 	local t=os.clock()
 	advtrains.detector.on_node={}
 	for k,v in pairs(advtrains.trains) do
+		advtrains.atprint_context_tid=sid(k)
 		advtrains.train_step_a(k, v, dtime)
 	end
 	for k,v in pairs(advtrains.trains) do
+		advtrains.atprint_context_tid=sid(k)
 		advtrains.train_step_b(k, v, dtime)
 	end
 	
+	advtrains.atprint_context_tid=nil
+	
 	atprintbm("trainsteps", t)
 	endstep()
 end
@@ -140,7 +144,7 @@ function advtrains.train_step_a(id, train, dtime)
 	end
 	--- 2. prepare initial path and index if needed ---
 	if not train.index then train.index=0 end
-	if not train.path or #train.path<2 then
+	if not train.path then
 		if not train.last_pos then
 			--no chance to recover
 			atprint("train hasn't saved last-pos, removing train.")
@@ -224,36 +228,43 @@ function advtrains.train_step_a(id, train, dtime)
 		train.tarvelocity=0
 	end
 	
+	--- 3a. this can be useful for debugs/warnings and is used for check_trainpartload ---
+	local t_info, train_pos=sid(id), train.path[math.floor(train.index)]
+	if train_pos then
+		t_info=t_info.." @"..minetest.pos_to_string(train_pos)
+	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.end_index<train.min_index_on_track
 	local pprint
+	
 	if front_off_track and back_off_track then--allow movement in both directions
 		if train.tarvelocity>1 then
 			train.tarvelocity=1
-			atwarn("Train",sid(id)," is off track at both ends. Clipping velocity to 1")
+			atwarn("Train",t_info,"is off track at both ends. Clipping velocity to 1")
 			pprint=true
 		end
 	elseif front_off_track then--allow movement only backward
 		if train.movedir==1 and train.tarvelocity>0 then
 			train.tarvelocity=0
-			atwarn("Train",sid(id)," is off track. Trying to drive further out. Velocity clipped to 0")
+			atwarn("Train",t_info,"is off track. Trying to drive further out. Velocity clipped to 0")
 			pprint=true
 		end
 		if train.movedir==-1 and train.tarvelocity>1 then
 			train.tarvelocity=1
-			atwarn("Train",sid(id)," is off track. Velocity clipped to 1")
+			atwarn("Train",t_info,"is off track. Velocity clipped to 1")
 			pprint=true
 		end
 	elseif back_off_track then--allow movement only forward
 		if train.movedir==-1 and train.tarvelocity>0 then
 			train.tarvelocity=0
-			atwarn("Train",sid(id)," is off track. Trying to drive further out. Velocity clipped to 0")
+			atwarn("Train",t_info,"is off track. Trying to drive further out. Velocity clipped to 0")
 			pprint=true
 		end
 		if train.movedir==1 and train.tarvelocity>1 then
 			train.tarvelocity=1
-			atwarn("Train",sid(id)," is off track. Velocity clipped to 1")
+			atwarn("Train",t_info,"is off track. Velocity clipped to 1")
 			pprint=true
 		end
 	end
@@ -322,7 +333,7 @@ function advtrains.train_step_a(id, train, dtime)
 	--why this is an extra function, see under 3.
 	advtrains.pathpredict(id, train, true)
 	
-	--make pos/yaw available for possible recover calls
+	--- 5a. 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]
@@ -339,6 +350,36 @@ function advtrains.train_step_a(id, train, dtime)
 		train.last_pos_prev=train.path[math.floor(train.index-0.5)]
 	end
 	
+	--- 5b. Remove path items that are no longer used ---
+	-- Necessary since path items are no longer invalidated in save steps
+	local path_pregen_keep=20
+	local offtrack_keep=4
+	local gen_front_keep= path_pregen_keep
+	local gen_back_keep= - train.trainlen - path_pregen_keep
+	
+	local delete_min=math.min(train.max_index_on_track - offtrack_keep, math.floor(train.index)+gen_back_keep)
+	local delete_max=math.max(train.min_index_on_track + offtrack_keep, math.floor(train.index)+gen_front_keep)
+	
+	if train.path_extent_min<delete_min then
+		atprint(sid(id),"clearing path min ",train.path_extent_min," to ",delete_min)
+		for i=train.path_extent_min,delete_min-1 do
+			train.path[i]=nil
+			train.path_dist[i]=nil
+		end
+		train.path_extent_min=delete_min
+		train.min_index_on_track=math.max(train.min_index_on_track, delete_min)
+	end
+	if train.path_extent_max>delete_max then
+		atprint(sid(id),"clearing path max ",train.path_extent_max," to ",delete_max)
+		train.path_dist[delete_max]=nil
+		for i=delete_max+1,train.path_extent_max do
+			train.path[i]=nil
+			train.path_dist[i]=nil
+		end
+		train.path_extent_max=delete_max
+		train.max_index_on_track=math.min(train.max_index_on_track, delete_max)
+	end
+	
 	--- 6. update node coverage ---
 	
 	-- when paths get cleared, the old indices set above will be up-to-date and represent the state in which the last run of this code was made
@@ -406,7 +447,7 @@ function advtrains.train_step_a(id, train, dtime)
 	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 then
-		local ori_pos=advtrains.get_real_index_position(path, train.index) --not much to calculate
+		local ori_pos=train_pos --see 3a.
 		--atprint("[train "..id.."] at "..minetest.pos_to_string(vector.round(ori_pos)))
 		
 		local should_check=false
@@ -429,6 +470,7 @@ end
 
 --about regular: Used by 1. to ensure path gets generated far enough, since end index is not known at this time.
 function advtrains.pathpredict(id, train, regular)
+	--TODO duplicate code under 5b.
 	local path_pregen=10
 	
 	local gen_front= path_pregen
@@ -440,7 +482,7 @@ function advtrains.pathpredict(id, train, regular)
 	
 	local maxn=train.path_extent_max or 0
 	while maxn < gen_front do--pregenerate
-		--atprint("maxn conway for ",maxn,minetest.pos_to_string(path[maxn]),maxn-1,minetest.pos_to_string(path[maxn-1]))
+		atprint("maxn conway for ",maxn,minetest.pos_to_string(train.path[maxn]),maxn-1,minetest.pos_to_string(train.path[maxn-1]))
 		local conway=advtrains.conway(train.path[maxn], train.path[maxn-1], train.drives_on)
 		if conway then
 			train.path[maxn+1]=conway
@@ -458,7 +500,7 @@ function advtrains.pathpredict(id, train, regular)
 	
 	local minn=train.path_extent_min or -1
 	while minn > gen_back do
-		--atprint("minn conway for ",minn,minetest.pos_to_string(path[minn]),minn+1,minetest.pos_to_string(path[minn+1]))
+		atprint("minn conway for ",minn,minetest.pos_to_string(train.path[minn]),minn+1,minetest.pos_to_string(train.path[minn+1]))
 		local conway=advtrains.conway(train.path[minn], train.path[minn+1], train.drives_on)
 		if conway then
 			train.path[minn-1]=conway
@@ -858,23 +900,37 @@ function advtrains.get_train_at_pos(pos)
 	return advtrains.detector.on_node[ph]
 end
 
-function advtrains.invalidate_all_paths()
-	--atprint("invalidating all paths")
+function advtrains.invalidate_all_paths(pos)
+	--if a position is given, only invalidate inside a radius to save performance
+	local inv_radius=50
+	atprint("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)
+		local exec=true
+		if pos and v.path and v.index and v.end_index then
+			--start and end pos of the train
+			local cmp1=v.path[math.floor(v.index)]
+			local cmp2=v.path[math.floor(v.end_index)]
+			if vector.distance(pos, cmp1)>inv_radius and vector.distance(pos, cmp2)>inv_radius then
+				exec=false
+			end
+		end
+		if exec then
+			--TODO duplicate code in init.lua avt_save()!
+			if v.index then
+				v.restore_add_index=v.index-math.floor(v.index+0.5)
+			end
+			v.path=nil
+			v.path_dist=nil
+			v.index=nil
+			v.end_index=nil
+			v.min_index_on_track=nil
+			v.max_index_on_track=nil
+			v.path_extent_min=nil
+			v.path_extent_max=nil
+			
+			v.detector_old_index=nil
+			v.detector_old_end_index=nil
 		end
-		v.path=nil
-		v.path_dist=nil
-		v.index=nil
-		v.end_index=nil
-		v.min_index_on_track=nil
-		v.max_index_on_track=nil
-		v.path_extent_min=nil
-		v.path_extent_max=nil
-		
-		v.detector_old_index=nil
-		v.detector_old_end_index=nil
 	end
 end
 

advtrains/advtrains_luaautomation/active_common.lua

@@ -49,7 +49,7 @@ function ac.getform(pos, meta_p)
 end
 
 function ac.after_dig_node(pos, node, player)
-	advtrains.invalidate_all_paths()
+	advtrains.invalidate_all_paths(pos)
 	advtrains.ndb.clear(pos)
 	local ph=minetest.pos_to_string(pos)
 	ac.nodes[ph]=nil