use gennotify instead of lbm for placement

keep the lbm for secondary structures

mods/MAPGEN/mcl_structures/api.lua

@@ -17,15 +17,35 @@ local registered_structures = {}
 }
 ]]--
 
+local function place_schem(pos, def, pr)
+	if not def then return end
+	if type(def.y_offset) == "function" then
+		y_offset = def.y_offset(pr)
+	elseif def.y_offset then
+		y_offset = def.y_offset
+	end
+	if def.filenames then
+		local file = def.filenames[pr:next(1,#def.filenames)]
+		local pp = vector.offset(pos,0,y_offset,0)
+		mcl_structures.place_schematic(pp, file, "random", nil, true, "place_center_x,place_center_z",def.after_place,pr,{pos,def})
+	elseif def.place_func and def.place_func(pos,def) then
+		def.after_place(pos,def)
+	end
+end
+
 function mcl_structures.register_structure(name,def,nospawn) --nospawn means it will be placed by another (non-nospawn) structure that contains it's structblock i.e. it will not be placed by mapgen directly
 	local structblock = "mcl_structures:structblock_"..name
-	minetest.register_node(":"..structblock, {drawtype="airlike", walkable = false, pointable = false,groups = {structblock=1,not_in_creative_inventory=1}})
 	local flags = "place_center_x, place_center_z, force_placement"
 	local y_offset = 0
+	local sbgroups = { structblock = 1, not_in_creative_inventory=1 }
 	if def.flags then flags = def.flags end
 	def.name = name
-	if nospawn == nil then
+	if nospawn then
+		sbgroups.structblock = nil
+		sbgroups.structblock_lbm = 1
+	else
 		def.deco = minetest.register_decoration({
+			name = "mcl_structures:deco_"..name,
 			decoration = structblock,
 			deco_type = "simple",
 			place_on = def.place_on,
@@ -39,31 +59,32 @@ function mcl_structures.register_structure(name,def,nospawn) --nospawn means it
 			y_max = def.y_max,
 			y_min = def.y_min
 		})
+		local deco_id = minetest.get_decoration_id("mcl_structures:deco_"..name)
+		minetest.set_gen_notify({decoration=true}, { deco_id })
+		minetest.register_on_generated(function(minp, maxp, blockseed)
+			local gennotify = minetest.get_mapgen_object("gennotify")
+			local pr = PseudoRandom(blockseed + 42)
+			for _, pos in pairs(gennotify["decoration#"..deco_id] or {}) do
+				local realpos = vector.offset(pos,0,-1,0)
+				minetest.remove_node(realpos)
+				place_schem(realpos,def,pr)
+			end
+		end)
 	end
+	minetest.register_node(":"..structblock, {drawtype="airlike", walkable = false, pointable = false,groups = sbgroups})
 	registered_structures[name] = def
 end
 
+--lbm for secondary structures (structblock included in base structure)
 minetest.register_lbm({
 	name = "mcl_structures:struct_lbm",
 	run_at_every_load = true,
-	nodenames = {"group:structblock"},
+	nodenames = {"group:structblock_lbm"},
 	action = function(pos, node)
 		local name = node.name:gsub("mcl_structures:structblock_","")
-		local pr = PseudoRandom(pos.x+pos.y+pos.z)
 		local def = registered_structures[name]
-		local y_offset = 0
+		if not def then return end
-		minetest.set_node(pos,{name="air"})
+		minetest.remove_node(pos)
-		if type(def.y_offset) == "function" then
+		place_schem(pos)
-			y_offset = def.y_offset(pr)
-		elseif def.y_offset then
-			y_offset = def.y_offset
-		end
-		if def.filenames then
-			local file = def.filenames[pr:next(1,#def.filenames)]
-			local pp = vector.offset(pos,0,y_offset,0)
-			mcl_structures.place_schematic(pp, file, "random", nil, true, "place_center_x,place_center_z",def.after_place,pr,{pos,def})
-		elseif def.place_func and def.place_func(pos,def) then
-			def.after_place(pos,def)
-		end
 	end
 })