VoxeLibre/mods/MAPGEN/mcl_villages/paths.lua

-------------------------------------------------------------------------------
-- generate paths between buildings
-------------------------------------------------------------------------------
function settlements.paths(settlement_info)
  local starting_point
  local end_point
  local distance
  --for k,v in pairs(settlement_info) do
  starting_point = settlement_info[1]["pos"] 
  for o,p in pairs(settlement_info) do

    end_point = settlement_info[o]["pos"] 
    if starting_point ~= end_point
    then
      -- loop until end_point is reched (distance == 0)
      while true do

        -- define surrounding pos to starting_point
        local north_p = {x=starting_point.x+1, y=starting_point.y, z=starting_point.z}
        local south_p = {x=starting_point.x-1, y=starting_point.y, z=starting_point.z}
        local west_p = {x=starting_point.x, y=starting_point.y, z=starting_point.z+1}
        local east_p = {x=starting_point.x, y=starting_point.y, z=starting_point.z-1}
        -- measure distance to end_point
        local dist_north_p_to_end = math.sqrt(
          ((north_p.x - end_point.x)*(north_p.x - end_point.x))+
          ((north_p.z - end_point.z)*(north_p.z - end_point.z))
        )
        local dist_south_p_to_end = math.sqrt(
          ((south_p.x - end_point.x)*(south_p.x - end_point.x))+
          ((south_p.z - end_point.z)*(south_p.z - end_point.z))
        )
        local dist_west_p_to_end = math.sqrt(
          ((west_p.x - end_point.x)*(west_p.x - end_point.x))+
          ((west_p.z - end_point.z)*(west_p.z - end_point.z))
        )
        local dist_east_p_to_end = math.sqrt(
          ((east_p.x - end_point.x)*(east_p.x - end_point.x))+
          ((east_p.z - end_point.z)*(east_p.z - end_point.z))
        )
        -- evaluate which pos is closer to the end_point
        if dist_north_p_to_end <= dist_south_p_to_end and
        dist_north_p_to_end <= dist_west_p_to_end and
        dist_north_p_to_end <= dist_east_p_to_end 
        then
          starting_point = north_p
          distance = dist_north_p_to_end

        elseif dist_south_p_to_end <= dist_north_p_to_end and
        dist_south_p_to_end <= dist_west_p_to_end and
        dist_south_p_to_end <= dist_east_p_to_end 
        then
          starting_point = south_p
          distance = dist_south_p_to_end

        elseif dist_west_p_to_end <= dist_north_p_to_end and
        dist_west_p_to_end <= dist_south_p_to_end and
        dist_west_p_to_end <= dist_east_p_to_end 
        then
          starting_point = west_p
          distance = dist_west_p_to_end

        elseif dist_east_p_to_end <= dist_north_p_to_end and
        dist_east_p_to_end <= dist_south_p_to_end and
        dist_east_p_to_end <= dist_west_p_to_end 
        then
          starting_point = east_p
          distance = dist_east_p_to_end
        end
        -- find surface of new starting point
        local surface_point, surface_mat = settlements.find_surface(starting_point)
        -- replace surface node with mcl_core:grass_path 
        if surface_point
        then
          if surface_mat == "mcl_core:sand" or surface_mat == "mcl_core:redsand" then
			minetest.swap_node(surface_point,{name="mcl_core:sandstonesmooth2"})
		  else
			minetest.swap_node(surface_point,{name="mcl_core:grass_path"})
		  end
          -- don't set y coordinate, surface might be too low or high
          starting_point.x = surface_point.x
          starting_point.z = surface_point.z
        end
        if distance <= 1 or
        starting_point == end_point
        then
          break
        end
      end
    end
  end
end