Added rail_grid lua and png files. Suitable for vanilla but also used on modded.

map_gen/maps/rail_grid.lua

@@ -0,0 +1,158 @@
+-- Map by Jayefuu, grilledham, R.Nukem and Soggs
+
+-- Notes:
+-- - We recommend playing with RSO to force expansion by rail
+-- - If playing with mods, do not use FARL, the rail placing mechanic will not work with this map
+
+-- Dependencies
+local b = require 'map_gen.shared.builders'
+local Random = require 'map_gen.shared.random'
+local table = require 'utils.table'
+local Event = require 'utils.event'
+local RS = require 'map_gen.shared.redmew_surface'
+local MGSP = require 'resources.map_gen_settings'
+local MSP = require 'resources.map_settings'
+local degrees = require "utils.math".degrees
+local ScenarioInfo = require 'features.gui.info'
+
+-- Setup surface and map settings
+RS.set_map_gen_settings(
+    {
+        MGSP.cliff_none,
+        MGSP.grass_disabled,
+        MGSP.enable_water,
+    }
+)
+
+ScenarioInfo.set_map_name('Rail Grid')
+ScenarioInfo.set_map_description(
+    [[
+Nauvis' factory planners have been disappointed with the recent trend towards
+rail spaghetti. As such they have enacted rules to enforce neat grid shaped
+rails and crossings.
+]]
+)
+ScenarioInfo.add_map_extra_info(
+    [[
+This map has green "city blocks" to enforce construction of rail in a grid
+pattern.
+
+You cannot place rail on any tile type except landfill. There is space at the
+grid intersections for junctions and turnarounds. There is space for
+two stations on each side of the grid.
+]]
+)
+
+
+RS.set_spawn_position({x = 20,y = 20})
+
+local function is_not_water_tile(x, y, world)
+    local gen_tile = world.surface.get_tile(world.x, world.y)
+    return not gen_tile.collides_with('water-tile')
+end
+
+
+local station_length = 40
+local station = b.any{
+    b.rectangle(station_length,18),
+    b.translate(b.square_diamond(18),station_length/2,0), -- these just make it pretty
+    b.translate(b.square_diamond(18),station_length/-2,0) -- these just make it pretty
+}
+
+local grid_size = 224
+local path = b.any{
+    b.square_diamond(40),
+    b.rectangle(grid_size,6),
+    b.rectangle(6,grid_size),
+    b.circular_pattern(b.rotate(station,degrees(90)), 4, grid_size/3)
+}
+
+path = b.change_tile(path, true, 'landfill')            -- MUST be landfill or the rail removal event doesn't work.
+local grid = b.single_grid_pattern(path, grid_size, grid_size)
+
+local no_water_grid = b.choose(is_not_water_tile, grid, b.full_shape)
+
+local map = b.if_else(no_water_grid, b.full_shape)
+map = b.translate(map,1,1)
+
+
+local tile_map ={
+    ['grass-1'] = 'dirt-1',
+    ['grass-2'] = 'dirt-2',
+    ['grass-3'] = 'dirt-3',
+    ['grass-4'] = 'dirt-4',
+}
+
+-- replace grass tiles with dirt so that the rail grid is much
+for old_tile, new_tile in pairs(tile_map) do
+    map = b.change_map_gen_tile(map, old_tile, new_tile)
+end
+
+-- This event removes rail and curve rail entities and removes them unless they are placed on landfill
+Event.add(
+    defines.events.on_built_entity,
+    function(event)
+        local entity = event.created_entity
+        if not entity or not entity.valid then
+            return
+        end
+        local name = entity.name
+
+		local ghost = false
+        if name == 'tile-ghost' or name == 'entity-ghost' then
+            ghost = true
+			ghost_name = entity.ghost_name
+        end
+
+        if (name ~= 'straight-rail') and (name ~= 'curved-rail') then
+			if not ghost then
+			    return
+			elseif (ghost_name ~= 'straight-rail') and (ghost_name ~= 'curved-rail') then
+				return
+			end
+        end
+
+        -- Check the bounding box for the tile
+        local status = true
+        local area = entity.bounding_box
+        local left_top = area.left_top
+        local right_bottom = area.right_bottom
+        local p = game.get_player(event.player_index)
+        --check for sand under all tiles in bounding box
+        for x = math.floor(left_top.x), math.floor(right_bottom.x), 1 do
+            for y = math.floor(left_top.y), math.floor(right_bottom.y), 1 do
+                if (p.surface.get_tile(x, y).name ~= 'landfill')then
+                    status = false
+                    break
+                end
+            end
+        end
+        if status == true then
+            return
+        else
+            --destroy entity and return to player
+            if not p or not p.valid then
+               return
+            end
+            entity.destroy()
+            if not ghost then
+                p.insert(event.stack)
+            end
+        end
+    end
+)
+
+-- On player join print a notice explaining the rail mechanic
+local function player_joined_game(event)
+    local player_index = event.player_index
+    local player = game.get_player(player_index)
+    if not player or not player.valid then
+        return
+    end
+
+    player.print("Welcome to RedMew's Rail Grids Map. Rails can only be built on green tiles.", {r=0, g=1, b=0, a=1})
+end
+
+Event.add(defines.events.on_player_joined_game, player_joined_game)
+
+return map