Cooperate with underworlds mod.

mapgen.lua

@@ -176,21 +176,21 @@ local function generate(p_minp, p_maxp, seed)
 	local csize = vector.add(vector.subtract(maxp, minp), 1)
   local write
 
+
+  if underworlds_mod and underworlds_mod.underzones then
+    local avg = (minp.y + maxp.y) / 2
+    for _, uz in pairs(underworlds_mod.underzones) do
+      if avg <= uz.upper_bound and avg >= uz.lower_bound then
+        return
+      end
+    end
+  end
+
 	if fun_caves_mod.use_bi_hi then
 		heightmap = minetest.get_mapgen_object("heightmap")
 	end
 
 
-	-- use the same seed (based on perlin noise).
-	--do
-	--	local seed = minetest.get_perlin(seed_noise):get2d({x=minp.x, y=minp.z})
-	--	if not (seed and type(seed) == 'number') then
-	--		return
-	--	end
-
-	--	math.randomseed(seed)
-	--end
-
 	-- Correct heightmap.
 	if maxp.y < -300 or minp.y > 300 then
 		for i = 1, #heightmap do