advtrains_line_automation/textures/advtrains_dtrack_stop_placer.png

--trainlogic.lua
--controls train entities stuff about connecting/disconnecting/colliding trains and other things


local benchmark=false
local bm={}
local bmlt=0
local bmsteps=0
local bmstepint=200
atprintbm=function(action, ta)
	if not benchmark then return end
	local t=(os.clock()-ta)*1000
	if not bm[action] then
		bm[action]=t
	else
		bm[action]=bm[action]+t
	end
	bmlt=bmlt+t
end
function endstep()
	if not benchmark then return end
	bmsteps=bmsteps-1
	if bmsteps<=0 then
		bmsteps=bmstepint
		for key, value in pairs(bm) do
			minetest.chat_send_all(key.." "..(value/bmstepint).." ms avg.")
		end
		minetest.chat_send_all("Total time consumed by all advtrains actions per step: "..(bmlt/bmstepint).." ms avg.")
		bm={}
		bmlt=0
	end
end

--acceleration for lever modes (trainhud.lua), per wagon
local t_accel_all={
	[0] = -10,
	[1] = -3,
	[2] = -0.5,
	[4] = 0.5,
}
--acceleration per engine
local t_accel_eng={
	[0] = 0,
	[1] = 0,
	[2] = 0,
	[4] = 1.5,
}

advtrains.mainloop_trainlogic=function(dtime)
	--build a table of all players indexed by pts. used by damage and door system.
	advtrains.playersbypts={}
	for _, player in pairs(minetest.get_connected_players()) do
		if not advtrains.player_to_train_mapping[player:get_player_name()] then
			--players in train are not subject to damage
			local ptspos=minetest.pos_to_string(vector.round(player:getpos()))
			advtrains.playersbypts[ptspos]=player
		end
	end
	--regular train step
	-- do in two steps: 
	--  a: predict path and add all nodes to the advtrains.detector.on_node table
	--  b: check for collisions based on these data
	--  (and more)
	local t=os.clock()
	advtrains.detector.on_node={}
	for k,v in pairs(advtrains.trains) do
		advtrains.atprint_context_tid=sid(k)
		advtrains.atprint_context_tid_full=k
		advtrains.train_step_a(k, v, dtime)
	end
	for k,v in pairs(advtrains.trains) do
		advtrains.atprint_context_tid=sid(k)
		advtrains.atprint_context_tid_full=k
		advtrains.train_step_b(k, v, dtime)
	end
	
	advtrains.atprint_context_tid=nil
	advtrains.atprint_context_tid_full=nil
	
	atprintbm("trainsteps", t)
	endstep()
end

minetest.register_on_joinplayer(function(player)
	return advtrains.pcall(function()
		local pname=player:get_player_name()
		local id=advtrains.player_to_train_mapping[pname]
		if id then
			local train=advtrains.trains[id]
			if not train then advtrains.player_to_train_mapping[pname]=nil return end
			--set the player to the train position.
			--minetest will emerge the area and load the objects, which then will call reattach_all().
			--because player is in mapping, it will not be subject to dying.
			player:setpos(train.last_pos_prev)
			--independent of this, cause all wagons of the train which are loaded to reattach their players
			--needed because already loaded wagons won't call reattach_all()
			for _,wagon in pairs(minetest.luaentities) do
				if wagon.is_wagon and wagon.initialized and wagon.train_id==id then
					wagon:reattach_all()
				end
			end
		end
	end)
end)

minetest.register_on_dieplayer(function(player)
	return advtrains.pcall(function()
		local pname=player:get_player_name()
		local id=advtrains.player_to_train_mapping[pname]
		if id then
			local train=advtrains.trains[id]
			if not train then advtrains.player_to_train_mapping[pname]=nil return end
			for _,wagon in pairs(minetest.luaentities) do
				if wagon.is_wagon and wagon.initialized and wagon.train_id==id then
					--when player dies, detach him from the train
					--call get_off_plr on every wagon since we don't know which one he's on.
					wagon:get_off_plr(pname)
				end
			end
		end
	end)
end)
--[[
train step structure:


- legacy stuff
- preparing the initial path and creating index
- setting node coverage old indices
- handle velocity influences:
	- off-track
	- atc
	- player controls
	- environment collision
- update index = move
- create path
- call stay_node on all old positions to register train there, for collision system
- do less important stuff such as checking trainpartload or removing

-- break --
- Call enter_node and leave_node callbacks (required here because stay_node needs to be called on all trains first)
- handle train collisions

]]

function advtrains.train_step_a(id, train, dtime)
	--atprint("--- runcnt ",advtrains.mainloop_runcnt,": index",train.index,"end_index", train.end_index,"| max_iot", train.max_index_on_track, "min_iot", train.min_index_on_track, "<> pe_min", train.path_extent_min,"pe_max", train.path_extent_max)
	if train.min_index_on_track then
		assert(math.floor(train.min_index_on_track)==train.min_index_on_track)
	end
	--- 1. not exactly legacy. required now because of saving ---
	if not train.drives_on or not train.max_speed then
		advtrains.update_trainpart_properties(id)
	end
	--TODO check for all vars to be present
	if not train.velocity then
		train.velocity=0
	end
	if not train.movedir or (train.movedir~=1 and train.movedir~=-1) then
		train.movedir=1
	end
	--- 2. prepare initial path and index if needed ---
	if not train.index then train.index=0 end
	if not train.path then
		if not train.last_pos then
			--no chance to recover
			atwarn("Unable to restore train ",id,": missing last_pos")
			advtrains.trains[id]=nil
			return false
		end
		
		local node_ok=advtrains.get_rail_info_at(advtrains.round_vector_floor_y(train.last_pos), train.drives_on)
		
		if node_ok==nil then
			--block not loaded, do nothing
			atprint("last_pos", advtrains.round_vector_floor_y(train.last_pos), "not loaded and not in ndb, waiting")
			return nil
		elseif node_ok==false then
			atprint("Unable to restore train ",id,": No rail at train's position")
			return false
		end
		
		if not train.last_pos_prev then
			--no chance to recover
			atwarn("Unable to restore train ",id,": missing last_pos_prev")
			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.drives_on)
		
		if prevnode_ok==nil then
			--block not loaded, do nothing
			atprint("last_pos_prev", advtrains.round_vector_floor_y(train.last_pos_prev), "not loaded and not in ndb, waiting")
			return nil
		elseif prevnode_ok==false then
			atprint("Unable to restore train ",id,": No rail at train's position")
			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)
		train.path_extent_min=-1
		train.path_extent_max=0
		train.min_index_on_track=-1
		train.max_index_on_track=0
		
		--[[
		Bugfix for trains randomly ignoring ATC rails:
		- Paths have been invalidated. 1 gets executed and ensures an initial path
		- 2a sets train end index. The problem is that path_dist is not known for the whole path, so train end index will be nearly trainlen
		- Since the detector indices are also unknown, they get set to the new (wrong) train_end_index. Enter_node calls are not executed for the nodes that lie in between real end_index and trainlen.
		- The next step, mistake is recognized, train leaves some positions. From there, everything works again.
		To overcome this, we will generate the full required path here so that path_dist is available for get_train_end_index(). 
		]]
		advtrains.pathpredict(id, train)
	end
	
	--- 2a. set train.end_index which is required in different places, IF IT IS NOT SET YET by STMT afterwards. ---
	---   table entry to avoid triple recalculation ---
	if not train.end_index then
		train.end_index=advtrains.get_train_end_index(train)
	end
	
	--- 2b. set node coverage old indices ---
	
	train.detector_old_index = atround(train.index)
	train.detector_old_end_index = atround(train.end_index)
	
	--- 3. handle velocity influences ---
	local train_moves=(train.velocity~=0)
	local tarvel_cap
	
	if train.recently_collided_with_env then
		tarvel_cap=0
		train.active_control=false
		if not train_moves then
			train.recently_collided_with_env=nil--reset status when stopped
		end
	end
	if train.locomotives_in_train==0 then
		tarvel_cap=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[atround(train.index)]
	if train_pos then
		t_info=t_info.." @"..minetest.pos_to_string(train_pos)
		--atprint("train_pos:",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
		tarvel_cap=1
	elseif front_off_track then--allow movement only backward
		if train.movedir==1 then
			tarvel_cap=0
		end
		if train.movedir==-1 then
			tarvel_cap=1
		end
	elseif back_off_track then--allow movement only forward
		if train.movedir==1 then
			tarvel_cap=1
		end
		if train.movedir==-1 then
			tarvel_cap=0
		end
	end
	
	--interpret ATC command and apply auto-lever control when not actively controlled
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