From defffbc952dbaca87ead6deb7a56a55425ba37c3 Mon Sep 17 00:00:00 2001
From: Wuzzy <almikes@aol.com>
Date: Mon, 11 Sep 2017 01:11:57 +0200
Subject: [PATCH] Fix generating lots of gravel in caves

---
 mods/MAPGEN/mcl_biomes/init.lua | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/mods/MAPGEN/mcl_biomes/init.lua b/mods/MAPGEN/mcl_biomes/init.lua
index d50ba807d..a41e2e8e4 100644
--- a/mods/MAPGEN/mcl_biomes/init.lua
+++ b/mods/MAPGEN/mcl_biomes/init.lua
@@ -54,7 +54,8 @@ local function register_biomes()
 	]]
 
 	local DEEP_OCEAN_MAX = -11
-	local OCEAN_MIN = DEEP_OCEAN_MAX + 1
+	local DEEP_OCEAN_MIN = -32 -- Careful when changing this. You might end up caves covered in gravel around Y=32!
+	local OCEAN_MIN = DEEP_OCEAN_MAX+1
 
 	-- Ice Plains Spikes
 	minetest.register_biome({
@@ -1082,12 +1083,20 @@ local function register_biomes()
 		depth_filler = 2,
 		node_riverbed = "mcl_core:gravel",
 		depth_riverbed = 2,
-		y_min = mcl_vars.mg_overworld_min,
+		y_min = DEEP_OCEAN_MIN,
 		y_max = DEEP_OCEAN_MAX,
 		heat_point = 50,
 		humidity_point = 50,
 	})
 
+	-- Underground biome, to prevent ocean floor materials “leaking” into the underground.
+	minetest.register_biome({
+		name = "underground",
+		y_min = mcl_vars.mg_overworld_min,
+		y_max = DEEP_OCEAN_MIN-1,
+		heat_point = 50,
+		humidity_point = 50,
+	})
 end
 
 -- Register biomes of non-Overworld biomes