Initial commit

1 files changed, 284 insertions, 0 deletions

diff --git a/railtrack/railtrack.lua b/railtrack/railtrack.lua
new file mode 100644
index 0000000..3a1f714
--- /dev/null
+++ b/railtrack/railtrack.lua
@@ -0,0 +1,284 @@
+RAILTRACK_WARN_SECTION_LEN = 20
+RAILTRACK_ROTATIONS = "FLR"
+RAILTRACK_ACCEL_FLAT = -0.5
+RAILTRACK_ACCEL_UP = -2
+RAILTRACK_ACCEL_DOWN = 2
+
+railtrack = {}
+
+railtrack.default_rail = {
+	description = "Rail",
+	drawtype = "raillike",
+	tiles = {"default_rail.png", "default_rail_curved.png",
+		"default_rail_t_junction.png", "default_rail_crossing.png"},
+	paramtype = "light",
+	sunlight_propagates = true,
+	walkable = false,
+	is_ground_content = false,
+	selection_box = {
+		type = "fixed",
+		fixed = {-1/2, -1/2, -1/2, 1/2, -1/2+1/16, 1/2},
+	},
+	groups = {bendy = 2, dig_immediate = 2, attached_node = 1,
+		connect_to_raillike = minetest.raillike_group("rail")},
+	railtype = "rail",
+	on_place = function(itemstack, placer, pointed_thing)
+		local name = placer:get_player_name()
+		if not name or pointed_thing.type ~= "node" then
+			return
+		end
+		if not minetest.is_singleplayer() then
+			if not minetest.check_player_privs(name, {rails=true}) then
+				minetest.chat_send_player(name, "Requires rails privilege")
+				return
+			end
+		end
+	end,
+	after_place_node = function(pos, placer, itemstack)
+		local meta = minetest.get_meta(pos)
+		local def = itemstack:get_definition() or {}
+		if def.acceleration then
+			meta:set_string("acceleration", def.acceleration)
+		end
+		local junc = {}
+		local contype = meta:get_string("contype") or ""
+		local s_cons = meta:get_string("connections") or ""
+		if contype == "section" then
+			railtrack:warn_section_len(placer, pos, meta)
+		elseif s_cons ~= "" then
+			local cons = minetest.deserialize(s_cons)
+			for _, con in pairs(cons) do
+				if railtrack:warn_section_len(placer, con) then
+					break
+				end
+			end
+		end
+	end,
+	on_construct = function(pos)
+		railtrack:update_rails(pos)
+	end,
+	after_destruct = function(pos)
+		local cons = railtrack:get_connections(pos)
+		for _, p in pairs(cons) do
+			railtrack:update_rails(p)
+		end
+	end,
+}
+
+function railtrack:register_rail(name, def)
+	for k, v in pairs(railtrack.default_rail) do
+		if not def[k] then
+			def[k] = v
+		end
+	end
+	def.inventory_image = def.inventory_image or def.tiles[1]
+	def.wield_image = def.wield_image or def.tiles[1]
+	minetest.register_node(name, def)
+end
+
+function railtrack:warn_section_len(player, pos, meta)
+	meta = meta or minetest.get_meta(pos)
+	local contype = meta:get_string("contype") or ""
+	if contype == "section" then
+		local s_junc = meta:get_string("junctions") or ""
+		if s_junc ~= "" then
+			local junc = minetest.deserialize(s_junc)
+			if #junc == 2 then
+				local dist = railtrack:get_distance(junc[1], junc[2])
+				if dist > RAILTRACK_WARN_SECTION_LEN then
+					local name = player:get_player_name()
+					if name then
+						minetest.chat_send_player(name, "Warning, section"
+								.." length "..dist.." exceeds the recommended"
+								.." maximum of "..RAILTRACK_WARN_SECTION_LEN)
+						return true
+					end
+				end
+			end
+		end
+	end
+end
+
+function railtrack:is_railnode(pos)
+	local node = minetest.get_node(pos)
+	if node then
+		return minetest.get_item_group(node.name, "connect_to_raillike") > 0
+	end
+end
+
+function railtrack:get_sign(z)
+	if z == 0 then
+		return 0
+	else
+		return z / math.abs(z)
+	end
+end
+
+function railtrack:get_rotations(s_rots, dir)
+	local rots = {}
+	for i = 1, string.len(s_rots) do
+		local r = string.sub(s_rots, i, i)
+		local rot = nil
+		if r == "F" then
+			rot = {x=dir.x, z=dir.z}
+		elseif r == "L" then
+			rot = {x=-dir.z, z=dir.x}
+		elseif r == "R" then
+			rot = {x=dir.z, z=-dir.x}
+		elseif r == "B" then
+			rot = {x=-dir.x, z=-dir.z}
+		end
+		if rot then
+			table.insert(rots, rot)
+		end
+	end
+	return rots
+end
+
+function railtrack:get_acceleration(pos)
+	local meta = minetest.get_meta(pos)
+	local accel = meta:get_string("acceleration") or ""
+	if accel ~= "" then
+		return tonumber(accel)
+	end
+end
+
+function railtrack:get_direction(p1, p2)
+	local v = vector.subtract(p1, p2)
+	return {
+		x = railtrack:get_sign(v.x),
+		y = railtrack:get_sign(v.y),
+		z = railtrack:get_sign(v.z),
+	}
+end
+
+function railtrack:get_distance(p1, p2)
+	local dx = p1.x - p2.x
+	local dz = p1.z - p2.z
+	return math.abs(dx) + math.abs(dz)
+end
+
+
+function railtrack:get_railtype(pos)
+	local node = minetest.get_node(pos) or {}
+	if node.name then
+		local ref = minetest.registered_items[node.name] or {}
+		return ref.railtype
+	end
+end
+
+function railtrack:get_connection_type(pos, cons)
+	local railtype = railtrack:get_railtype(pos)
+	if #cons == 0 then
+		return "single"
+	elseif #cons == 1 then
+		return "junction"
+	elseif #cons == 2 then
+		if cons[1].x == cons[2].x or cons[1].z == cons[2].z then
+			if (cons[1].y == cons[2].y and cons[1].y == pos.y) or
+					(math.abs(cons[1].y - cons[2].y) == 2) then
+				if railtype == railtrack:get_railtype(cons[1]) and
+						railtype == railtrack:get_railtype(cons[2]) then
+					return "section"
+				end
+			end
+		end
+	end
+	return "junction"
+end
+
+function railtrack:get_connections(pos)
+	local connections = {}
+	for y = -1, 1 do
+		for x = -1, 1 do
+			for z = -1, 1 do
+				if math.abs(x) ~= math.abs(z) then
+					local p = vector.add(pos, {x=x, y=y, z=z})
+					if railtrack:is_railnode(p) then
+						table.insert(connections, p)
+					end
+				end
+			end
+		end
+	end
+	return connections
+end
+
+function railtrack:get_junctions(pos, last_pos, junctions)
+	junctions = junctions or {}
+	local cons = railtrack:get_connections(pos)
+	local contype = railtrack:get_connection_type(pos, cons)
+	if contype == "junction" then
+		table.insert(junctions, pos)
+	elseif contype == "section" then
+		if last_pos then
+			for i, p in pairs(cons) do
+				if vector.equals(p, last_pos) then
+					cons[i] = nil
+				end
+			end
+		end
+		for _, p in pairs(cons) do
+			railtrack:get_junctions(p, pos, junctions)
+		end
+	end
+	return junctions
+end
+
+function railtrack:set_acceleration(pos, accel)
+	local meta = minetest.get_meta(pos)
+	local contype = meta:get_string("contype")
+	if contype == "section" then
+		local s_junc = meta:get_string("junctions") or ""
+		local junc = minetest.deserialize(s_junc) or {}
+		if #junc == 2 then
+			local p = vector.new(junc[2])
+			local dir = railtrack:get_direction(junc[1], junc[2])
+			local dist = railtrack:get_distance(junc[1], junc[2])
+			for i = 0, dist do
+				local m = minetest.get_meta(p)
+				if m then
+					m:set_string("acceleration", tostring(accel))
+				end
+				p = vector.add(dir, p)
+			end
+		end
+	else
+		meta:set_string("acceleration", tostring(accel))
+	end
+end
+
+function railtrack:update_rails(pos, last_pos, level)
+	local connections = {}
+	local junctions = {}
+	local meta = minetest.get_meta(pos)
+	local cons = railtrack:get_connections(pos)
+	local contype = railtrack:get_connection_type(pos, cons)
+	level = level or 0
+	for i, p in pairs(cons) do
+		connections[i] = p
+	end
+	if contype == "junction" then
+		level = level + 1
+	end
+	if contype == "section" or level < 2 then
+		if last_pos then
+			for i, p in pairs(cons) do
+				if vector.equals(p, last_pos) then
+					cons[i] = nil
+				end
+			end
+		end
+		for _, p in pairs(cons) do
+			railtrack:update_rails(p, pos, level)
+		end
+	end
+	if contype == "section" then
+		junctions = railtrack:get_junctions(pos)
+		connections = {}
+	end
+	meta:set_string("connections", minetest.serialize(connections))
+	meta:set_string("junctions", minetest.serialize(junctions))
+	meta:set_string("contype", contype)
+end
+