MapGen: add detection of rooms walls in dungeons. Relates to #1140 #1141

mods/lord/Core/builtin/src/mapgen.lua

@@ -1,11 +1,115 @@
+local pairs, table_insert, id
+	= pairs, table.insert, minetest.get_content_id
 
 
 local on_generated_is_registered    = false
 local on_dungeon_generated_handlers = {}
 
---- @param callback fun(minp:Position, maxp:Position, data:table, area:VoxelArea, room_centers:Position[])
+local c_air = id("air")
+
+
+--- @class RoomWall
+--- @field start_pos Position
+--- @field end_pos   Position
+
+--- @class RoomWalls
+--- @field north   RoomWall
+--- @field south   RoomWall
+--- @field east    RoomWall
+--- @field west    RoomWall
+--- @field floor   RoomWall
+--- @field ceiling RoomWall
+
+--- @param rc       Position room center
+--- @param wx_minus number
+--- @param wx_plus  number
+--- @param wz_minus number
+--- @param wz_plus  number
+--- @param data     table
+--- @param area     VoxelArea
+--- @return number|nil
+local function find_room_high_y(rc, wx_minus, wx_plus, wz_minus, wz_plus, data, area)
+	for dy = 1, 16 do
+		if
+			data[area:index(wx_plus  - 1, rc.y + dy,  rc.z        )] ~= c_air or
+			data[area:index(wx_minus + 1, rc.y + dy,  rc.z        )] ~= c_air or
+			data[area:index(rc.x,         rc.y + dy,  wz_plus  - 1)] ~= c_air or
+			data[area:index(rc.x,         rc.y + dy,  wz_minus + 1)] ~= c_air
+		then
+			return rc.y + dy - 1
+		end
+	end
+
+	return nil
+end
+
+--- @param room_center Position[]
+--- @param data table
+--- @param area VoxelArea
+--- @return RoomWalls|RoomWall[]|table
+local function find_room_walls(room_center, data, area)
+	local rc = room_center
+	local wx_plus, wx_minus, wz_plus, wz_minus
+	for delta = 1, 8 do
+		if wx_plus == nil  and data[area:index(rc.x + delta, rc.y, rc.z)] ~= c_air then wx_plus  = rc.x + delta end
+		if wx_minus == nil and data[area:index(rc.x - delta, rc.y, rc.z)] ~= c_air then wx_minus = rc.x - delta end
+		if wz_plus == nil  and data[area:index(rc.x, rc.y, rc.z + delta)] ~= c_air then wz_plus  = rc.z + delta end
+		if wz_minus == nil and data[area:index(rc.x, rc.y, rc.z - delta)] ~= c_air then wz_minus = rc.z - delta end
+	end
+	if wx_plus == nil or wx_minus == nil or wz_plus == nil or wz_minus == nil then
+		return {}
+	end
+
+	local high_y = find_room_high_y(rc, wx_minus, wx_plus, wz_minus, wz_plus, data, area)
+	if high_y == nil then
+		return {}
+	end
+
+	return {
+		west    = {
+			start_pos = { x = wx_minus, y = rc.y, z = wz_minus },
+			end_pos   = { x = wx_minus, y = high_y, z = wz_plus },
+		},
+		east    = {
+			start_pos = { x = wx_plus, y = rc.y, z = wz_minus },
+			end_pos   = { x = wx_plus, y = high_y, z = wz_plus },
+		},
+		south   = {
+			start_pos = { x = wx_minus, y = rc.y, z = wz_minus },
+			end_pos   = { x = wx_plus, y = high_y, z = wz_minus },
+		},
+		north   = {
+			start_pos = { x = wx_minus, y = rc.y, z = wz_plus },
+			end_pos   = { x = wx_plus, y = high_y, z = wz_plus },
+		},
+		floor   = {
+			start_pos = { x = wx_minus, y = rc.y - 1, z = wz_minus },
+			end_pos   = { x = wx_plus, y = rc.y - 1, z = wz_plus },
+		},
+		ceiling = {
+			start_pos = { x = wx_minus, y = high_y + 1, z = wz_minus },
+			end_pos   = { x = wx_plus, y = high_y + 1, z = wz_plus },
+		},
+	}
+end
+
+--- @param data table
+--- @param area VoxelArea
+--- @param room_centers Position[]
+--- @return RoomWalls[]
+local function detect_rooms_walls(data, area, room_centers)
+	local rooms_walls = {}
+	for _, room_center in pairs(room_centers) do
+		table_insert(rooms_walls, find_room_walls(room_center, data, area))
+	end
+
+	return rooms_walls
+end
+
+-- luacheck: no max line length
+--- @param callback fun(minp:Position, maxp:Position, data:table, area:VoxelArea, room_centers:Position[], rooms_walls:RoomWall[][])
 minetest.register_on_dungeon_generated = function(callback)
-	table.insert(on_dungeon_generated_handlers, callback)
+	table_insert(on_dungeon_generated_handlers, callback)
 
 	if on_generated_is_registered then
 		return
@@ -22,8 +126,10 @@ minetest.register_on_dungeon_generated = function(callback)
 		local area           = VoxelArea:new({ MinEdge = emin, MaxEdge = emax })
 		local data           = vm:get_data()
 
+		local rooms_walls = detect_rooms_walls(data, area, notify.dungeon)
+
 		for _, on_dungeon_generated_handler in pairs(on_dungeon_generated_handlers) do
-			on_dungeon_generated_handler(minp, maxp, data, area, notify.dungeon)
+			on_dungeon_generated_handler(minp, maxp, data, area, notify.dungeon, rooms_walls)
 		end
 
 		vm:set_data(data)