new module

modules/surrounded_by_worms.lua

@@ -0,0 +1,40 @@
+local event = require 'utils.event'
+local math_random = math.random
+local turrets = {
+	[1] = "small-worm-turret",
+	[2] = "medium-worm-turret",
+	[3] = "big-worm-turret",
+	[4] = "behemoth-worm-turret"
+}
+
+local tile_coords = {}
+for x = 0, 31, 1 do
+	for y = 0, 31, 1 do
+		tile_coords[#tile_coords + 1] = {x, y}
+	end
+end
+
+local function on_chunk_generated(event)
+	local surface = event.surface
+	local starting_distance = surface.map_gen_settings.starting_area * 200
+	local left_top = event.area.left_top
+	local chunk_distance_to_center = math.sqrt(left_top.x ^ 2 + left_top.y ^ 2)
+	if starting_distance > chunk_distance_to_center then return end
+	
+	local highest_worm_tier = math.floor((chunk_distance_to_center - starting_distance) * 0.002) + 1
+	if highest_worm_tier > 4 then highest_worm_tier = 4 end
+	
+	if not global.average_worm_amount_per_chunk then global.average_worm_amount_per_chunk = 1 end	
+	local worm_amount = math_random(math.floor(global.average_worm_amount_per_chunk * 0.5), math.ceil(global.average_worm_amount_per_chunk * 1.5))
+	
+	for a = 1, worm_amount, 1 do
+		local coord_modifier = tile_coords[math_random(1, #tile_coords)]
+		local pos = {left_top.x + coord_modifier[1], left_top.y + coord_modifier[2]}
+		local name = turrets[math_random(1, highest_worm_tier)]
+		if surface.can_place_entity({name = name, position = pos}) then
+			surface.create_entity({name = name, position = pos, force = "enemy"})
+		end
+	end
+end
+
+event.add(defines.events.on_chunk_generated, on_chunk_generated)