Implement multi-occupation in detector.on_node table to finally fix collisions

4 files changed, 73 insertions, 28 deletions

diff --git a/advtrains/tracks.lua b/advtrains/tracks.lua
index fa7f84d..3771090 100644
--- a/advtrains/tracks.lua
+++ b/advtrains/tracks.lua
@@ -430,20 +430,71 @@ end
 advtrains.detector = {}

 advtrains.detector.on_node = {}

 

-function advtrains.detector.enter_node(pos, train_id)

+--Returns true when position is occupied by a train other than train_id, false when occupied by the same train as train_id and nil in case there's no train at all

+function advtrains.detector.occupied(pos, train_id)

+	local ppos=advtrains.round_vector_floor_y(pos)

+	local pts=minetest.pos_to_string(ppos)

+	local s=advtrains.detector.on_node[pts]

+	if not s then return nil end

+	if s==train_id then return false end

+	--in case s is a table, it's always occupied by another train

+	return true

+end

+-- If given a train id as second argument, this is considered as 'not there'.

+-- Returns the train id of (one of, nondeterministic) the trains at this position

+function advtrains.detector.get(pos, train_id)

 	local ppos=advtrains.round_vector_floor_y(pos)

 	local pts=minetest.pos_to_string(ppos)

-	advtrains.detector.on_node[pts]=train_id

+	local s=advtrains.detector.on_node[pts]

+	if not s then return nil end

+	if type(s)=="table" then 

+		for _,t in ipairs(s) do

+			if t~=train_id then return t end

+		end

+		return nil

+	end

+	return s

+end

+

+function advtrains.detector.enter_node(pos, train_id)

+	advtrains.detector.stay_node(pos, train_id)

+	local ppos=advtrains.round_vector_floor_y(pos)

 	advtrains.detector.call_enter_callback(ppos, train_id)

 end

 function advtrains.detector.leave_node(pos, train_id)

 	local ppos=advtrains.round_vector_floor_y(pos)

+	local pts=minetest.pos_to_string(ppos)

+	local s=advtrains.detector.on_node[pts]

+	if type(s)=="table" then

+		local i

+		for j,t in ipairs(s) do

+			if t==train_id then i=j end

+		end

+		if not i then return end

+		s=table.remove(s,i)

+		if #s==0 then

+			s=nil

+		elseif #s==1 then

+			s=s[1]

+		end

+		advtrains.detector.on_node[pts]=s

+	else

+		advtrains.detector.on_node[pts]=nil

+	end

 	advtrains.detector.call_leave_callback(ppos, train_id)

 end

 function advtrains.detector.stay_node(pos, train_id)

 	local ppos=advtrains.round_vector_floor_y(pos)

 	local pts=minetest.pos_to_string(ppos)

-	advtrains.detector.on_node[pts]=train_id

+	

+	local s=advtrains.detector.on_node[pts]

+	if not s then

+		advtrains.detector.on_node[pts]=train_id

+	elseif type(s)=="string" then

+		advtrains.detector.on_node[pts]={s, train_id}

+	elseif type(s)=="table" then

+		advtrains.detector.on_node[pts]=table.insert(s, train_id)

+	end

 end

 

 

diff --git a/advtrains/trainlogic.lua b/advtrains/trainlogic.lua
index 64b40f1..228c3a0 100644
--- a/advtrains/trainlogic.lua
+++ b/advtrains/trainlogic.lua
@@ -394,15 +394,12 @@ function advtrains.train_step_a(id, train, dtime)
 	
 	--- 6b. call stay_node to register trains in the location table - actual enter_node stuff is done in step b ---
 	
-	local ifn, ibn = atround(train.index), atround(train.end_index)
+	local ifo, ibo = train.detector_old_index, train.detector_old_end_index
 	local path=train.path
 	
-	for i=ibn, ifn do
+	for i=ibo, ifo do
 		if path[i] then
-			local pts=minetest.pos_to_string(path[i])
-			if not (advtrains.detector.on_node[pts] and advtrains.detector.on_node[pts]~=id) then
-				advtrains.detector.stay_node(path[i], id)
-			end
+			advtrains.detector.stay_node(path[i], id)
 		end
 	end
 	
@@ -519,13 +516,12 @@ function advtrains.train_step_b(id, train, dtime)
 		if ifn>ifo then
 			for i=ifo+1, ifn do
 				if path[i] then
-					local pts=minetest.pos_to_string(path[i])
-					if advtrains.detector.on_node[pts] and advtrains.detector.on_node[pts]~=id then
+					if advtrains.detector.occupied(path[i], id) then
 						--if another train has signed up for this position first, it won't be recognized in train_step_b. So do collision here.
-						atprint("Collision detected in enter_node callbacks (front) @",pts,"with",sid(advtrains.detector.on_node[pts]))
-						advtrains.collide_and_spawn_couple(id, path[i], advtrains.detector.on_node[pts], false)
+						atprint("Collision detected in enter_node callbacks (front) @",path[i],"with",sid(advtrains.detector.get(path[i], id)))
+						advtrains.collide_and_spawn_couple(id, path[i], advtrains.detector.get(path[i], id), false)
 					end
-					atprint("enter_node (front) @index",i,"@",pts,"on_node",sid(advtrains.detector.on_node[pts]))
+					atprint("enter_node (front) @index",i,"@",path[i],"on_node",sid(advtrains.detector.get(path[i], id)))
 					advtrains.detector.enter_node(path[i], id)
 				end
 			end
@@ -540,12 +536,12 @@ function advtrains.train_step_b(id, train, dtime)
 			for i=ibn, ibo-1 do
 				if path[i] then
 					local pts=minetest.pos_to_string(path[i])
-					if advtrains.detector.on_node[pts] and advtrains.detector.on_node[pts]~=id then
+					if advtrains.detector.occupied(path[i], id) then
 						--if another train has signed up for this position first, it won't be recognized in train_step_b. So do collision here.
-						atprint("Collision detected in enter_node callbacks (back) @",pts,"on_node",sid(advtrains.detector.on_node[pts]))
-						advtrains.collide_and_spawn_couple(id, path[i], advtrains.detector.on_node[pts], true)
+						atprint("Collision detected in enter_node callbacks (back) @",path[i],"with",sid(advtrains.detector.get(path[i], id)))
+						advtrains.collide_and_spawn_couple(id, path[i], advtrains.detector.get(path[i], id), true)
 					end
-					atprint("enter_node (back) @index",i,"@",pts,"with",sid(advtrains.detector.on_node[pts]))
+					atprint("enter_node (back) @index",i,"@",path[i],"on_node",sid(advtrains.detector.get(path[i], id)))
 					advtrains.detector.enter_node(path[i], id)
 				end
 			end
@@ -576,15 +572,14 @@ function advtrains.train_step_b(id, train, dtime)
 				for z=-1,1 do
 					local testpos=vector.add(rcollpos, {x=x, y=0, z=z})
 					--- 8a Check collision ---
-					local testpts=minetest.pos_to_string(testpos)
-					if advtrains.detector.on_node[testpts] and advtrains.detector.on_node[testpts]~=id then
+					if advtrains.detector.occupied(testpos, id) then
 						--collides
-						advtrains.collide_and_spawn_couple(id, testpos, advtrains.detector.on_node[testpts], train.movedir==-1)
+						advtrains.collide_and_spawn_couple(id, testpos, advtrains.detector.get(testpos, id), train.movedir==-1)
 					end
 					--- 8b damage players ---
 					if not minetest.settings:get_bool("creative_mode") then
 						local player=advtrains.playersbypts[testpts]
-						if player and train.velocity>3 then
+						if player and not minetest.check_player_privs(player, "creative") and train.velocity>3 then
 							--instantly kill player
 							--drop inventory contents first, to not to spawn bones
 							local player_inv=player:get_inventory()
@@ -716,8 +711,8 @@ function advtrains.split_train_at_wagon(wagon)
 	if not train.path then return end
 	
 	local real_pos_in_train=advtrains.get_real_path_index(train, wagon.pos_in_train)
-	local pos_for_new_train=train.path[math.floor(real_pos_in_train+wagon.wagon_span+1)]
-	local pos_for_new_train_prev=train.path[math.floor(real_pos_in_train+wagon.wagon_span)]
+	local pos_for_new_train=train.path[math.floor(real_pos_in_train+wagon.wagon_span)]
+	local pos_for_new_train_prev=train.path[math.floor(real_pos_in_train+wagon.wagon_span-1)]
 	
 	--before doing anything, check if both are rails. else do not allow
 	if not pos_for_new_train then
@@ -930,8 +925,7 @@ function advtrains.invert_train(train_id)
 end
 
 function advtrains.get_train_at_pos(pos)
-	local ph=minetest.pos_to_string(advtrains.round_vector_floor_y(pos))
-	return advtrains.detector.on_node[ph]
+	return advtrains.detector.get(pos)
 end
 
 function advtrains.invalidate_all_paths(pos)
diff --git a/advtrains_itrainmap/init.lua b/advtrains_itrainmap/init.lua
index 756f1da..0443609 100644
--- a/advtrains_itrainmap/init.lua
+++ b/advtrains_itrainmap/init.lua
@@ -52,7 +52,7 @@ local function create_map_form(d)
 		if x>=minx and x<=maxx then
 			for z,y in pairs(itx) do
 				if z>=minz and z<=maxz then
-					local adn=advtrains.detector.on_node[minetest.pos_to_string({x=x, y=y, z=z})]
+					local adn=advtrains.detector.get({x=x, y=y, z=z})
 					local color="gray"
 					if adn then
 						color="red"
diff --git a/advtrains_luaautomation/atc_rail.lua b/advtrains_luaautomation/atc_rail.lua
index 1fae28d..b90baf8 100644
--- a/advtrains_luaautomation/atc_rail.lua
+++ b/advtrains_luaautomation/atc_rail.lua
@@ -24,7 +24,7 @@ function r.fire_event(pos, evtdata)
 	
 	--prepare ingame API for ATC. Regenerate each time since pos needs to be known
 	--If no train, then return false.
-	local train_id=advtrains.detector.on_node[ph]
+	local train_id=advtrains.detector.get(pos)
 	local train, atc_arrow, tvel
 	if train_id then train=advtrains.trains[train_id] end
 	if train then