Merge pull request #8 from oversword/issue-4-revised

Implemented new method of defining valid faces through the secondary node registration

internal2.lua

@@ -284,13 +284,17 @@ function Tube:determine_tube_dirs(pos, preferred_pos, fdir)
 	-- Check for secondary nodes (chests and so on)
 	for dir = 1,6 do
 		if allowed[dir] then
-			local _,npos = self:get_secondary_node(pos, dir)
-			if npos then 
-				if preferred_pos and vector.equals(npos, preferred_pos) then
-					preferred_pos = nil
-					table.insert(tbl, 2, dir)
+			local node,npos = self:get_secondary_node(pos, dir)
+			if npos then
+				if self:is_valid_dir(node, Turn180Deg[dir]) == false then
+					allowed[dir] = false
 				else
-					table.insert(tbl, dir)
+					if preferred_pos and vector.equals(npos, preferred_pos) then
+						preferred_pos = nil
+						table.insert(tbl, 2, dir)
+					else
+						table.insert(tbl, dir)
+					end
 				end
 			end
 		end
@@ -332,6 +336,8 @@ function Tube:add_tube_dir(pos, dir)
 	if param2 then
 		local d1, d2, num = self:decode_param2(npos, param2)
 		if not num then return end
+		-- if invalid face, do nothing
+		if self:is_valid_dir_pos(pos, dir) == false then return end
 		-- not already connected to the new tube?
 		dir = Turn180Deg[dir]
 		if d1 ~= dir and dir ~= d2 then
@@ -379,6 +385,9 @@ end
 function Tube:get_next_teleport_node(pos, dir)
 	if pos then
 		local npos = vector.add(pos, Dir6dToVector[dir or 0])
+		if self:is_valid_dir_pos(npos, Turn180Deg[dir]) == false then
+			return
+		end
 		local meta = M(npos)
 		local s = meta:get_string("tele_pos")
 		if s ~= "" then

tube_api.lua

@@ -23,12 +23,34 @@ local M = minetest.get_meta
 local MP = minetest.get_modpath("tubelib2")
 local I,_ = dofile(MP.."/intllib.lua")
 
+-- Cardinal directions, regardless of orientation
 local Dir2Str = {"north", "east", "south", "west", "down", "up"}
 
 function tubelib2.dir_to_string(dir)
 	return Dir2Str[dir]
 end
 
+-- Relative directions, dependant on orientation (param2)
+local DirToSide = {"B", "R", "F", "L", "D", "U"}
+
+function tubelib2.dir_to_side(dir, param2)
+	if dir < 5 then
+		dir = (((dir - 1) - (param2 % 4)) % 4) + 1
+	end
+	return DirToSide[dir]
+end
+
+local SideToDir = {B=1, R=2, F=3, L=4, D=5, U=6}
+
+function tubelib2.side_to_dir(side, param2)
+	local dir = SideToDir[side]
+	if dir < 5 then
+		dir = (((dir - 1) + (param2 % 4)) % 4) + 1
+	end
+	return dir
+end
+
+
 local function Tbl(list)
 	local tbl = {}
 	for _,item in ipairs(list) do
@@ -159,6 +181,8 @@ local function update_secondary_nodes_after_node_dug(self, pos, dirs)
 			tmp, npos = self:get_secondary_node(pos, dir) 
 		end
 		if npos then
+			self:del_from_cache(npos, Turn180Deg[dir])
+			self:del_from_cache(pos, dir)
 			self:update_secondary_node(npos, Turn180Deg[dir])
 			self:update_secondary_node(pos, dir)
 		end
@@ -175,6 +199,7 @@ function Tube:new(attr)
 		max_tube_length = attr.max_tube_length or 1000, 
 		primary_node_names = Tbl(attr.primary_node_names or {}), 
 		secondary_node_names = Tbl(attr.secondary_node_names or {}),
+		valid_node_contact_sides = {},
 		show_infotext = attr.show_infotext or false,
 		force_to_use_tubes = attr.force_to_use_tubes or false, 
 		clbk_after_place_tube = attr.after_place_tube,
@@ -187,6 +212,9 @@ function Tube:new(attr)
 	o.valid_dirs = Tbl(o.dirs_to_check)
 	setmetatable(o, self)
 	self.__index = self
+	if attr.valid_node_contact_sides then
+		o:set_valid_sides_multiple(attr.valid_node_contact_sides)
+	end
 	return o
 end
 
@@ -197,6 +225,87 @@ function Tube:add_secondary_node_names(names)
 	end
 end
 
+
+-- Defaults for valid sides configuration
+local function invert_booleans(tab)
+	local inversion = {}
+	for key, value in pairs(tab) do
+		inversion[key] = not value
+	end
+	return inversion
+end
+local valid_sides_default_true = Tbl(DirToSide)
+local valid_sides_default_false = invert_booleans(valid_sides_default_true)
+local function complete_valid_sides(valid_sides, existing_defaults)
+	local valid_sides_complete = {}
+	for side, default_value in pairs(existing_defaults) do
+		local new_value = valid_sides[side]
+		if new_value == nil then
+			valid_sides_complete[side] = default_value
+		else
+			valid_sides_complete[side] = new_value
+		end
+	end
+	return valid_sides_complete
+end
+
+-- Set sides which are valid
+-- with a table of name = valid_sides pairs
+function Tube:set_valid_sides_multiple(names)
+	for name, valid_sides in pairs(names) do
+		self:set_valid_sides(name, valid_sides)
+	end
+end
+
+-- Set sides which are invalid
+-- with a table of name = valid_sides pairs
+function Tube:set_invalid_sides_multiple(names)
+	for name, invalid_sides in pairs(names) do
+		self:set_invalid_sides(name, invalid_sides)
+	end
+end
+
+-- Set sides which are valid
+-- will assume all sides not given are invalid
+-- Only sets new sides, existing sides will remain
+function Tube:set_valid_sides(name, valid_sides)
+	local existing_defaults = self.valid_node_contact_sides[name] or valid_sides_default_false
+	self.valid_node_contact_sides[name] = complete_valid_sides(Tbl(valid_sides), existing_defaults)
+end
+
+-- Set sides which are invalid
+-- will assume all sides not given are valid
+-- Only sets new sides, existing sides will remain
+function Tube:set_invalid_sides(name, invalid_sides)
+	local existing_defaults = self.valid_node_contact_sides[name] or valid_sides_default_true
+	self.valid_node_contact_sides[name] = complete_valid_sides(invert_booleans(Tbl(invalid_sides)), existing_defaults)
+end
+
+-- Checks the list of valid node connection sides to
+-- see if a given side can be connected to
+function Tube:is_valid_side(name, side)
+	local valid_sides = self.valid_node_contact_sides[name]
+	if valid_sides then
+		return valid_sides[side] or false
+	end
+end
+
+-- Checks if a particular node can be connected to
+-- from a particular direction, taking into account orientation
+function Tube:is_valid_dir(node, dir)
+	if node and dir ~= nil and self.valid_node_contact_sides[node.name] then
+		local side = tubelib2.dir_to_side(dir, node.param2)
+		return self:is_valid_side(node.name, side)
+	end
+end
+
+-- Checks if a node at a particular position can be connected to
+-- from a particular direction, taking into account orientation
+function Tube:is_valid_dir_pos(pos, dir)
+	local node = self:get_node_lvm(pos)
+	return self:is_valid_dir(node, dir)
+end
+
 -- Register further nodes, which should be updated after
 -- a node/tube is placed/dug
 function Tube:add_special_node_names(names)