Implement initial rail connection logic (no vertical track yet), experiment with texture modifiers and gravel underlay for display (not working)

mods/ENTITIES/mcl_minecarts/init.lua

@@ -948,7 +948,7 @@ local function register_minecart(def)
 	register_entity(def.entity_id, def)
 	register_craftitem(def.itemstring, def.entity_id, def.description, def.tt_help, def.longdesc, def.usagehelp, def.icon, def.creative)
 	if minetest.get_modpath("doc_identifier") then
-		doc.sub.identifier.register_object(def.entity_id, "craftitems", itemstring)
+		doc.sub.identifier.register_object(def.entity_id, "craftitems", def.itemstring)
 	end
 end
 

mods/ENTITIES/mcl_minecarts/rails.lua

@@ -1,6 +1,10 @@
 local modname = minetest.get_current_modname()
 local modpath = minetest.get_modpath(modname)
 local mod = mcl_minecarts
+mod.RAIL_GROUPS = {
+	STANDARD = 1,
+	CURVES = 2,
+}
 local S = minetest.get_translator(modname)
 
 local function drop_railcarts(pos)
@@ -73,9 +77,10 @@ local function register_rail_v2(itemstring, def)
 
 	-- Build rail groups
 	local groups = table.copy(RAIL_DEFAULT_GROUPS)
-	if def.groups then table.merge(groups, def.groups) end
+	if def.groups then table_merge(groups, def.groups) end
 	def.groups = groups
 
+
 	-- Build the node definition
 	local ndef = {
 		drawtype = "nodebox",
@@ -93,9 +98,11 @@ local function register_rail_v2(itemstring, def)
 	if not ndef.inventory_image then ndef.inventory_image = ndef.tiles[1] end
 	if not ndef.wield_image then ndef.wield_image = ndef.tiles[1] end
 
+	print("registering rail "..itemstring.." with definition: "..dump(ndef))
+
 	-- Make registrations
 	minetest.register_node(itemstring, ndef)
-	minetest.register_craft(craft)
+	if craft then minetest.register_craft(craft) end
 end
 mod.register_rail = register_rail_v2
 

mods/ENTITIES/mcl_minecarts/rails/standard.lua

@@ -1,21 +1,189 @@
 local modname = minetest.get_current_modname()
 local modpath = minetest.get_modpath(modname)
 local mod = mcl_minecarts
-local S = minetest.get_translator(modname)
 
-mod.register_rail("mcl_minecarts:rail_v2", {
+-- This is a candidate for adding to mcl_util
-	tiles = {"default_rail.png"},
+local function table_merge(base, overlay)
+	for k,v in pairs(overlay) do
+		if type(base[k]) == "table" then
+			table_merge(base[k], v)
+		else
+			base[k] = v
+		end
+	end
+	return base
+end
+
+local north = vector.new( 0, 0, 1); local N = 1
+local south = vector.new( 0, 0,-1); local S = 2 -- Note: this is overwritten below
+local east  = vector.new( 1, 0, 0); local E = 4
+local west  = vector.new(-1, 0, 0); local W = 8
+
+local HORIZONTAL_CONNECTIONS = { north, south, east, west }
+local HORIZONTAL_STANDARD_MAPPINGS = {
+	[N]       = "_ns",
+	[S]       = "_ns",
+	[N+S]     = "_ns",
+
+	[E]       = "_ew",
+	[W]       = "_ew",
+	[E+W]     = "_ew",
+}
+local HORIZONTAL_CURVES_MAPPINGS = {
+	[N+E]     = "_corner_ne",
+	[N+W]     = "_corner_nw",
+	[S+E]     = "_corner_se",
+	[S+W]     = "_corner_sw",
+
+	[N+E+W]   = "_tee_new_off",
+	[S+E+W]   = "_tee_sew_off",
+	[N+S+E]   = "_tee_nse_off",
+	[N+S+W]   = "_tee_nsw_off",
+
+--	[N+S+E+W] = "_cross",
+}
+table_merge(HORIZONTAL_CURVES_MAPPINGS, HORIZONTAL_STANDARD_MAPPINGS)
+local HORIZONTAL_MAPPINGS_BY_RAIL_GROUP = {
+	[1] = HORIZONTAL_STANDARD_MAPPINGS,
+	[2] = HORIZONTAL_CURVES_MAPPINGS,
+}
+print(dump(HORIZONTAL_MAPPINGS_BY_RAIL_GROUP))
+local DIRECTION_BITS = {N, S, E, W}
+
+local function update_rail_connections(pos, update_neighbors)
+	local node = minetest.get_node(pos)
+	local nodedef = minetest.registered_nodes[node.name]
+	if not nodedef._mcl_minecarts then
+		minetest.log("warning", "attemting to rail connect "..node.name)
+		return
+	end
+
+	-- Get the mappings to use
+	local mappings = HORIZONTAL_MAPPINGS_BY_RAIL_GROUP[nodedef.groups.rail]
+	if not mappings then return end
+
+	-- Horizontal rules, Check for rails on each neighbor
+	local connections = 0
+	for i = 1,4 do
+		local neighbor = vector.add(pos, HORIZONTAL_CONNECTIONS[i])
+		local node = minetest.get_node(neighbor)
+		local nodedef = minetest.registered_nodes[node.name]
+
+		if nodedef.groups.rail then
+			connections = connections + DIRECTION_BITS[i]
+		end
+
+		if update_neighbors then
+			update_rail_connections(neighbor, false)
+		end
+	end
+
+	local mapping = mappings[connections]
+	if mapping then
+		local new_name = nodedef._mcl_minecarts.base_name..mapping
+		if new_name ~= node.name then
+			print("swapping "..node.name.." for "..new_name.." at "..tostring(pos))
+			node.name = new_name
+			minetest.swap_node(pos, node)
+		end
+	end
+end
+mod.update_rail_connections = update_rail_connections
+
+-- Now get the translator after we have finished using S for other things
+local S = minetest.get_translator(modname)
+local BASE_DEF = {
 	description = S("Rail"),
 	_tt_help = S("Track for minecarts"),
 	_doc_items_longdesc = S("Rails can be used to build transport tracks for minecarts. Normal rails slightly slow down minecarts due to friction."),
 	_doc_items_usagehelp = mod.text.railuse,
+	groups = {
+		rail = mod.RAIL_GROUPS.CURVES,
+	},
+	after_place_node = function(pos, placer, itemstack, pointed_thing)
+		update_rail_connections(pos, true)
+	end,
+}
+local CORNERS = {
+	{ "nw", "I" },
+	{ "ne", "R90" },
+	{ "se", "R180" },
+	{ "sw", "R270" },
+}
+local TEES = {
+	{ "nse", "I", "FX" },
+	{ "nsw", "R90", "FXR90" },
+	{ "new", "R180", "FY" },
+	{ "sew", "R270", "FYR90" },
+}
+local function register_curves_rail(base_name, tiles, def)
+	def = def or {}
+	local base_def = table.copy(BASE_DEF)
+	table_merge(base_def,{
+		_mcl_minecarts = { base_name = base_name },
+		drop = base_name.."_ns",
+	})
+	table_merge(base_def, def)
+
+	-- Register the base node
+	mod.register_rail(base_name.."_ns", table_merge(table.copy(base_def),{
+		tiles = {"default_gravel.png^"..tiles[1]},
+	}))
+	BASE_DEF.craft = nil
+
+	-- East-west variant
+	mod.register_rail(base_name.."_ew", table_merge(table.copy(base_def),{
+		tiles = { "default_gravel.png^[transformR90:"..tiles[1].."" },
+		groups = {
+			not_in_creative_inventory = 1,
+		},
+	}))
+
+	-- Corner variants
+	for _,c in ipairs(CORNERS) do
+		mod.register_rail(base_name.."_corner_"..c[1], table_merge(table.copy(base_def),{
+			tiles = { "default_gravel.png^[transform"..c[2]..":"..tiles[2] },
+			groups = {
+				not_in_creative_inventory = 1,
+			},
+		}))
+	end
+
+	-- Tee variants
+	for _,t in ipairs(TEES) do
+		mod.register_rail(base_name.."_tee_"..t[1].."_off", table_merge(table.copy(base_def),{
+			tiles = { "default_gravel.png^[transform"..t[2]..":"..tiles[3] },
+			groups = {
+				not_in_creative_inventory = 1,
+			},
+		}))
+		mod.register_rail(base_name.."_tee_"..t[1].."_on", table_merge(table.copy(base_def),{
+			tiles = { "default_gravel.png^[transform"..t[3]..":"..tiles[3] },
+			groups = {
+				not_in_creative_inventory = 1,
+			},
+		}))
+	end
+
+	-- Cross variant
+	--[[
+	mod.register_rail(base_name.."_cross", table_merge(table.copy(base_def),{
+		tiles = { tiles[4] },
+		groups = {
+			not_in_creative_inventory = 1,
+		},
+	}))
+	]]
+end
+mod.register_curves_rail = register_curves_rail
+register_curves_rail("mcl_minecarts:rail", {"default_rail.png", "default_rail_curved.png", "default_rail_t_junction.png", "default_rail_crossing.png"},{
 	craft = {
-		output = "mcl_minecarts:rail_v2 16",
+		output = "mcl_minecarts:rail_ns 16",
 		recipe = {
 			{"mcl_core:iron_ingot", "", "mcl_core:iron_ingot"},
 			{"mcl_core:iron_ingot", "mcl_core:stick", "mcl_core:iron_ingot"},
 			{"mcl_core:iron_ingot", "", "mcl_core:iron_ingot"},
 		}
-	}
+	},
 })