assets/blender/subway-train_animate_mirrored_solidify_uv.blend1

-- wagon.lua
-- Holds all logic related to wagons
-- From now on, wagons are, just like trains, just entries in a table
-- All data that is static is stored in the entity prototype (self).
--   A copy of the entity prototype is always available inside wagon_prototypes
-- All dynamic data is stored in the (new) wagons table
-- An entity is ONLY spawned by update_trainpart_properties when it finds it useful.
-- Only data that are only important to the entity itself are stored in the luaentity

-- TP delay when getting off wagon
local GETOFF_TP_DELAY = 0.5

local IGNORE_WORLD = advtrains.IGNORE_WORLD

advtrains.wagons = {}
advtrains.wagon_alias = {}
advtrains.wagon_prototypes = setmetatable({}, {
	__index = function(t, k)
		local rtn_val = rawget(t, k)
		if rtn_val ~= nil then
			return rtn_val
		end
		local alias = advtrains.wagon_alias[k]
		if alias then
			return rawget(t, alias)
		end
		return nil
	end
})
advtrains.wagon_objects = {}

local unload_wgn_range = advtrains.wagon_load_range + 32
function advtrains.wagon_outside_range(pos) -- returns true if the object is outside of unload_wgn_range of any player
	return not advtrains.position_in_range(pos, unload_wgn_range)
end

local setting_show_ids = minetest.settings:get_bool("advtrains_show_ids")

--
function advtrains.create_wagon(wtype, owner)
	local new_id=advtrains.random_id()
	while advtrains.wagons[new_id] do new_id=advtrains.random_id() end
	local wgn = {}
	wgn.type = wtype
	wgn.seatp = {}
	wgn.owner = owner
	wgn.id = new_id
	---wgn.train_id = train_id   --- will get this via update_trainpart_properties
	advtrains.wagons[new_id] = wgn
	--atdebug("Created new wagon:",wgn)
	return new_id
end

local function make_inv_name(uid)
	return "detached:advtrains_wgn_"..uid
end


local wagon={
	collisionbox = {-0.5,-0.5,-0.5, 0.5,0.5,0.5},
	--physical = true,
	visual = "mesh",
	mesh = "wagon.b3d",
	visual_size = {x=1, y=1},
	textures = {"black.png"},
	is_wagon=true,
	wagon_span=1,--how many index units of space does this wagon consume
	wagon_width=3, -- Wagon width in meters
	has_inventory=false,
	static_save=false,
}


function wagon:train()
	local data = advtrains.wagons[self.id]
	return advtrains.trains[data.train_id]
end


function wagon:on_activate(sd_uid, dtime_s)
	if sd_uid~="" then
		--destroy when loaded from static block.
		self.object:remove()
		return
	end
	self.object:set_armor_groups({immortal=1})
end

local function invcallback(id, pname, rtallow, rtfail)
	local data = advtrains.wagons[id]
	if data and advtrains.check_driving_couple_protection(pname, data.owner, data.whitelist) then
		return rtallow
	end
	return rtfail
end

function wagon:set_id(wid)
	self.id = wid
	self.initialized = true
	
	local data = advtrains.wagons[self.id]
	advtrains.wagon_objects[self.id] = self.object
	
	--atdebug("Created wagon entity:",self.name," w_id",wid," t_id",data.train_id)
	
	if self.has_inventory then
		--to be used later
		local inv=minetest.get_inventory({type="detached", name="advtrains_wgn_"..self.id})
		-- create inventory, if not yet created
		if not inv then	
			inv=minetest.create_detached_inventory("advtrains_wgn_"..self.id, {
				allow_move = function(inv, from_list, from_index, to_list, to_index, count, player)
					return invcallback(wid, player:get_player_name(), count, 0)
				end,
				allow_put = function(inv, listname, index, stack, player)
					return invcallback(wid, player:get_player_name(), stack:get_count(), 0)
				end,
				allow_take = function(inv, listname, index, stack, player)
					return invcallback(wid, player:get_player_name(), stack:get_count(), 0)
				end
			})
			if data.ser_inv then
				advtrains.deserialize_inventory(data.ser_inv, inv)
			end
			if self.inventory_list_sizes then
				for lst, siz in pairs(self.inventory_list_sizes) do
					inv:set_size(lst, siz)
				end
			end
		end
	end
	self.door_anim_timer=0
	self.door_state=0
	
	minetest.after(0.2, function() self:reattach_all() end)
	
	
	if self.set_textures then
		self:set_textures(data)
	end
	
	if self.custom_on_activate then
		self:custom_on_activate()
	end
end

function wagon:get_staticdata()
	return "STATIC"
end

function wagon:ensure_init()
			-- Note: A wagon entity won't exist when there's no train, because the train is
			-- the thing that actually creates the entity
			-- Train not being set just means that this will happen as soon as the train calls update_trainpart_properties.
	if self.initialized and self.id then
		local data = advtrains.wagons[self.id]
		if data and data.train_id and self:train() then
			if self.noninitticks then self.noninitticks=nil end
			return true
		end
	end
	if not self.noninitticks then
		atwarn("wagon",self.id,"uninitialized init=",self.initialized)
		self.noninitticks=0
	end
	self.noninitticks=self.noninitticks+1
	if self.noninitticks>20 then
		atwarn("wagon",self.id,"uninitialized, removing")
		self:destroy()
	else
		self.object:set_velocity({x=0,y=0,z=0})
	end
	return false
end

function wagon:train()
	local data = advtrains.wagons[self.id]
	return advtrains.trains[data.train_id]
end

-- Remove the wagon
function wagon:on_punch(puncher, time_from_last_punch, tool_capabilities, direction)
		if not self:ensure_init() then return end
		
		local data = advtrains.wagons[self.id]
	
		if not puncher or not puncher:is_player() then
			return
		end
		if data.owner and puncher:get_player_name()~=data.owner and (not minetest.check_player_privs(puncher, {train_admin = true })) then
		   minetest.chat_send_player(puncher:get_player_name(), attrans("This wagon is owned by @1, you can't destroy it.", data.owner));
		   return
		end
		
		if self.custom_may_destroy then
			if not self.custom_may_destroy(self, puncher, time_from_last_punch, tool_capabilities, direction) then
				return
			end
		end
		local itemstack = puncher:get_wielded_item()
		-- WARNING: This part of the API is guaranteed to change! DO NOT USE!
		if self.set_livery and itemstack:get_name() == "bike:painter" then
			self:set_livery(puncher, itemstack, data)
			return
		end
		-- check whether wagon has an inventory. Is is empty?
		if self.has_inventory then
			local inv=minetest.get_inventory({type="detached", name="advtrains_wgn_"..self.id})
			if not inv then -- inventory is not initialized when wagon was never loaded - should never happen
				atwarn("Destroying wagon with inventory, but inventory is not found? Shouldn't happen!")
				return
			end
			for listname, _ in pairs(inv:get_lists()) do
				if not inv:is_empty(listname) then
					minetest.chat_send_player(puncher:get_player_name(), attrans("The wagon's inventory is not empty!"));
					return
				end
			end
		end
		
		if #(self:train().trainparts)>1 then
		   minetest.chat_send_player(puncher:get_player_name(), attrans("Wagon needs to be decoupled from other wagons in order to destroy it."));
		   return
		end

		local pc=puncher:get_player_control()
		if not pc.sneak then
			minetest.chat_send_player(puncher:get_player_name(), attrans("Warning: If you destroy this wagon, you only get some steel back! If you are sure, hold Sneak and left-click the wagon."))
			return
		end
		
		
		if not self:destroy() then return end

		local inv = puncher:get_inventory()
		for _,item in ipairs(self.drops or {self.name}) do
			inv:add_item("main", item)
		end
end
function wagon:destroy()
	--some rules:
	-- you get only some items back
	-- single left-click shows warning
	-- shift leftclick destroys
	-- not when a driver is inside
	if self.id then
		local data = advtrains.wagons[self.id]
		if not data then
			atwarn("wagon:destroy(): data is not set!")
			return
		end
		
		if self.custom_on_destroy then
			self.custom_on_destroy(self)
		end
		
		for seat,_ in pairs(data.seatp) do
			self:get_off(seat)
		end
		
		if data.train_id and self:train() then
			advtrains.remove_train(data.train_id)
			advtrains.wagons[self.id]=nil
			if self.discouple then self.discouple.object:remove() end--will have no effect on unloaded objects
		end
	end
	--atdebug("[wagon ", self.id, "]: destroying")
	
	self.object:remove()
	return true
end

function wagon:is_driver_stand(seat)
	if self.seat_groups then
		return (seat.driving_ctrl_access or self.seat_groups[seat.group].driving_ctrl_access)
	else
		return seat.driving_ctrl_access
	end
	
end

function wagon:on_step(dtime)
		if not self:ensure_init() then return end
		
		if advtrains.is_no_action() then
			self.object:remove()
			return
		end
		
		local t=os.clock()
		local pos = self.object:get_pos()
		local data = advtrains.wagons[self.id]
		
		if not pos then
			--atdebug("["..self.id.."][fatal] missing position (object:getpos() returned nil)")
			return
		end
		
		if not data.seatp then
			data.seatp={}
		end
		if not self.seatpc then
			self.seatpc={}
		end
		
		local train=self:train()
		
		local is_in_loaded_area = advtrains.is_node_loaded(pos)

		--custom on_step function
		if self.custom_on_step then
			self:custom_on_step(dtime, data, train)
		end

		--driver control
		for seatno, seat in ipairs(self.seats) do
			local pname=data.seatp[seatno]
			local driver=pname and minetest.get_player_by_name(pname)
			local has_driverstand = pname and advtrains.check_driving_couple_protection(pname, data.owner, data.whitelist)
			has_driverstand = has_driverstand and self:is_driver_stand(seat)
			if has_driverstand and driver then
				advtrains.update_driver_hud(driver:get_player_name(), self:train(), data.wagon_flipped)
			elseif driver then
				--only show the inside text
				local inside=self:train().text_inside or ""
				advtrains.set_trainhud(driver:get_player_name(), inside)
			end
			if driver and driver:get_player_control_bits()~=self.seatpc[seatno] then
				local pc=driver:get_player_control()
				self.seatpc[seatno]=driver:get_player_control_bits()
				
				if has_driverstand then
					--regular driver stand controls
					advtrains.on_control_change(pc, self:train(), data.wagon_flipped)
					--bordcom
					if pc.sneak and pc.jump then
						self:show_bordcom(data.seatp[seatno])
					end
					--sound horn when required
					if self.horn_sound and pc.aux1 and not pc.sneak and not self.horn_handle then
						self.horn_handle = minetest.sound_play(self.horn_sound, {
							object = self.object,
							gain = 1.0, -- default
							max_hear_distance = 128, -- default, uses an euclidean metric
							loop = true,
						})
					elseif not pc.aux1 and self.horn_handle then
						minetest.sound_stop(self.horn_handle)
						self.horn_handle = nil
					end
				else
					-- If on a passenger seat and doors are open, get off when W or D pressed.
					local pass = data.seatp[seatno] and minetest.get_player_by_name(data.seatp[seatno])
					if pass and self:train().door_open~=0 then
					local pc=pass:get_player_control()
						if pc.up or pc.down then
							self:get_off(seatno)
						end
					end		      
				end
				if pc.aux1 and pc.sneak then
					self:get_off(seatno)
				end
			end
		end
		
		--check infotext
		local outside=train.text_outside or ""
		if setting_show_ids then
			outside = outside .. "\nT:" .. data.train_id .. " W:" .. self.id .. " O:" .. data.owner
		end
		
		
		--show off-track information in outside text instead of notifying the whole server about this
		if train.off_track then
			outside = outside .."\n!!! Train off track !!!"
		end
		
		-- liquid container: display liquid contents in infotext
		if self.techage_liquid_capacity then
			if data.techage_liquid and data.techage_liquid.name then
				outside = outside .."\nLiquid: "..data.techage_liquid.name..", "..data.techage_liquid.amount.." units"
			else
				outside = outside .."\nLiquid: empty"
			end
		end
		
		if self.infotext_cache~=outside  then
			self.object:set_properties({infotext=outside})
			self.infotext_cache=outside
		end
		
		local fct=data.wagon_flipped and -1 or 1
		
		--door animation
		if self.doors then
			if (self.door_anim_timer or 0)<=0 then
				local dstate = (train.door_open or 0) * fct
				if dstate ~= self.door_state then
					local at
					--meaning of the train.door_open field:
					-- -1: left doors (rel. to train orientation)
					--  0: closed
					--  1: right doors
					--this code produces the following behavior:
					-- if changed from 0 to +-1, play open anim. if changed from +-1 to 0, play close.
					-- if changed from +-1 to -+1, first close and set 0, then it will detect state change again and run open.
					if self.door_state == 0 then
						if self.doors.open.sound then minetest.sound_play(self.doors.open.sound, {object = self.object}) end
						at=self.doors.open[dstate]
						self.object:set_animation(at.frames, at.speed or 15, at.blend or 0, false)
						self.door_state = dstate
					else
						if self.doors.close.sound then minetest.sound_play(self.doors.close.sound, {object = self.object}) end
						at=self.doors.close[self.door_state or 1]--in case it has not been set yet
						self.object:set_animation(at.frames, at.speed or 15, at.blend or 0, false)
						self.door_state = 0
					end
					self.door_anim_timer = at.time
				end
			else
				self.door_anim_timer = (self.door_anim_timer or 0) - dtime
			end
		end
		
		--for path to be available. if not, skip step
		if not train.path or train.no_step then
			self.object:set_velocity({x=0, y=0, z=0})
			self.object:set_acceleration({x=0, y=0, z=0})
			return
		end
		if not data.pos_in_train then
			return
		end
		
		-- Calculate new position, yaw and direction vector
		-- note: "index" is needed to be the center index, required by door code
		local index = advtrains.path_get_index_by_offset(train, train.index, -data.pos_in_train)
		local pos, yaw, npos, npos2, vdir

		-- use new position logic?
		if self.wheel_positions then
			-- request two positions, calculate difference and yaw from this
			-- depending on flipstate, need to invert wheel pos indices -> wheelpos * fct
			local index1 = advtrains.path_get_index_by_offset(train, index, self.wheel_positions[1] * fct)
			local index2 = advtrains.path_get_index_by_offset(train, index, self.wheel_positions[2] * fct)
			local pos1 = advtrains.path_get_interpolated(train, index1)
			local pos2 = advtrains.path_get_interpolated(train, index2)
			npos = advtrains.path_get(train, atfloor(index)) -- need npos just for node loaded check
			-- calculate center of 2 positions and vdir vector
			-- if wheel positions are asymmetric, needs to weight by the difference!
			local fact = self.wheel_positions[1] / (self.wheel_positions[1]-self.wheel_positions[2])
			pos = {x=pos1.x-(pos1.x-pos2.x)*fact, y=pos1.y-(pos1.y-pos2.y)*fact, z=pos1.z-(pos1.z-pos2.z)*fact}
			if data.wagon_flipped then
				vdir = vector.normalize(vector.subtract(pos2, pos1))
			else
				vdir = vector.normalize(vector.subtract(pos1, pos2))
			end
			yaw = math.atan2(-vdir.x, vdir.z)
		else
			--old position logic (for small wagons): use center index and just get position
			pos, yaw, npos, npos2 = advtrains.path_get_interpolated(train, index)
			vdir = vector.normalize(vector.subtract(npos2, npos))
		end
		
		--automatic get_on
		--needs to know index and path
		if train.velocity==0 and self.door_entry and train.door_open and train.door_open~=0 then
			--using the mapping created by the trainlogic globalstep
			for i, ino in ipairs(self.door_entry) do
				--fct is the flipstate flag from door animation above
				local aci = advtrains.path_get_index_by_offset(train, index, ino*fct)
				local ix1, ix2 = advtrains.path_get_adjacent(train, aci)
				-- the two wanted positions are ix1 and ix2 + (2nd-1st rotated by 90deg)
				-- (x z) rotated by 90deg is (-z x)  (http://stackoverflow.com/a/4780141)
				local add = { x = (ix2.z-ix1.z)*train.door_open, y = 0, z = (ix1.x-ix2.x)*train.door_open }
				local pts1=vector.round(vector.add(ix1, add))
				local pts2=vector.round(vector.add(ix2, add))
				if minetest.get_item_group(minetest.get_node(pts1).name, "platform")>0 then
					local ckpts={
						pts1,
						pts2,
						vector.add(pts1, {x=0, y=1, z=0}),
						vector.add(pts2, {x=0, y=1, z=0}),
					}
					for _,ckpos in ipairs(ckpts) do
						local cpp=minetest.pos_to_string(ckpos)
						if advtrains.playersbypts[cpp] then
							self:on_rightclick(advtrains.playersbypts[cpp])
						end
					end
				end
			end
		end
		
		--checking for environment collisions(a 3x3 cube around the center)
		if not IGNORE_WORLD and is_in_loaded_area and not train.recently_collided_with_env then
			local collides=false
			local exh = self.extent_h or 1
			local exv = self.extent_v or 2
			for x=-exh,exh do
				for y=0,exv do
					for z=-exh,exh do