Camas/mods/village/mapgen.lua

minetest.register_node(
   "village:entity_spawner",
   {
      description = "Chunk defs may choose which entities to spawn here",
      tiles = {"default_brick.png^default_book.png"},
      is_ground_content = false,
      groups = {dig_immediate = 2},
      sounds = default.node_sound_wood_defaults()
})

minetest.register_node(
   "village:grassland_village",
   {
      description = "Village spawner",
      tiles = {"default_grass.png^default_book.png"},
      is_ground_content = false,
      groups = {dig_immediate = 2},
      sounds = default.node_sound_wood_defaults()
})

minetest.register_node(
   "village:grassland_village_mg",
   {
      description = "Mapgen village spawner(Has chance of not spawning village)",
      drawtype = "airlike",
      paramtype = "light",
      sunlight_propagates = true,
      walkable = false,
      pointable = false,
      diggable = false,
      buildable_to = false,
      is_ground_content = true,
      air_equivalent = true,
      drop = "",
      groups = {not_in_craftingguide = 1},
})

minetest.register_abm(
   {
      nodenames = {"village:grassland_village", "village:grassland_village_mg"},
      interval = 1,
      chance = 1,
      action = function(pos, node)
         minetest.remove_node(pos)

         if minetest.setting_getbool("mapgen_disable_villages") == true then
            return
         end

         local pr = PseudoRandom(minetest.get_mapgen_params().seed+pos.x+pos.y+pos.z)

         if node.name  == "village:grassland_village_mg" then
            if ((minetest.get_mapgen_params().seed+pos.x+pos.y+pos.z) % 30) == 1 then
               local nearest = village.get_nearest_village(pos)

               if nearest.dist > village.min_spawn_dist then
                  minetest.log("Spawning a (Mapgen)Grassland village at "..dump(pos))

                  -- a short delay to (hopefully) ensure that the surrounding terrain is generated
                  minetest.after(3.0, function() village.spawn_village(pos, pr) end)
               else
                  minetest.log("Cannot spawn village, too near another village")
               end
            end
         else
            minetest.log("Spawning a Grassland village at "..dump(pos))

            village.spawn_village(pos, pr)
         end
      end
})

minetest.register_decoration(
   {
      deco_type = "simple",
      place_on = "default:dirt_with_grass",
      sidelen = 16,
      fill_ratio = 0.005,
      biomes = {"Grassland", "Forest"},
      decoration = {"village:grassland_village_mg"},
      y_min = 1,
      y_max = 1000,
})