mapgen function for nssb

nssb_mapgen.lua

schemepath  = minetest .get_modpath('nssb') ..'/schems/'

function nssb_register_buildings(
  build_name,    -- name of schematic
  rand,          -- 1/rand is probability of spawning
  required,      -- required block to to spawn on

  height,        -- under this height, schematic can spawn
  near,          -- scan if this node is near
  width2fill  )  -- width of schematic, to fill dirt / ice under

  minetest .register_on_generated(
    function( minp,  maxp,  seed )

      height = height or 0  -- default to 0 if nil given

      if ( height >= 0 and minp.y > 0 ) -- aboveground
      or maxp.y < height then -- belowground

        local i, j, k
        local placed_scheme  = false

        i  = math.random( minp.x,  maxp.x )
        j  = math.random( minp.y,  maxp.y )
        k  = math.random( minp.z,  maxp.z )

        local node = { x = i,  y = j,  z = k }
        local nodename = minetest.env :get_node(node) .name

        if nodename == required_block and math.random( 1, rand ) == 1 then
          if minetest .find_node_near( node,  4,  near ) then

              minetest .place_schematic(  node,
                schemepath ..build ..'.mts',  '0',  {},  true  )
              placed_scheme  = true
          end -- find_node_near()
        end -- if nodename == required_block and...

        -- fill space below scheme, if required
        if placed_scheme and width > 0 then
          for dx  = -width,  width *2 do
            for dz  = -width,  width *2 do
              local gap2fill  = {  x  = node.x +dx,
                                   y  = node.y -1,
                                   z  = node.z +dz  }
              local nodename  = minetest .env :get_node( gap2fill ) .name

              while nodename == 'air'
                 or nodename == 'default:water_source'
                 or nodename == 'default:water_flowing'
                 or nodename == 'default:lava_flowing'
                 or nodename == 'default:lava_source' do
                  minetest .env :set_node(  gap2fill,  { name = required } )

                  gap2fill.y  = gap2fill.y -1
                  nodename  = minetest .env :get_node( gap2fill ) .name
              end  -- while air or water or lava
            end  -- dz
          end  -- dx
        end  -- if placed_scheme and width > 0
      end  -- if height aboveground or underground
    end  -- function( minp,  maxp,  seed )
  )  -- .register_on_generated()
end  -- nssb_register_buildings()