From 73957c46b279200222f524356b9e9cf28841fc08 Mon Sep 17 00:00:00 2001
From: Wuzzy <almikes@aol.com>
Date: Thu, 23 Feb 2017 00:15:47 +0100
Subject: [PATCH] Partially re-implement Superflat

---
 mods/CORE/mcl_init/init.lua          | 15 +++++++--
 mods/MAPGEN/mcl_biomes/init.lua      | 23 ++++++++++++--
 mods/MAPGEN/mcl_mapgen_core/init.lua | 47 +++++++++++++++++-----------
 3 files changed, 62 insertions(+), 23 deletions(-)

diff --git a/mods/CORE/mcl_init/init.lua b/mods/CORE/mcl_init/init.lua
index 01bcc8442..6c2a414e2 100644
--- a/mods/CORE/mcl_init/init.lua
+++ b/mods/CORE/mcl_init/init.lua
@@ -8,8 +8,19 @@ mcl_vars.gui_bg_img = ""
 
 mcl_vars.inventory_header = mcl_vars.gui_slots .. mcl_vars.gui_bg
 
-mcl_vars.bedrock_overworld_min = -62
-mcl_vars.bedrock_overworld_max = -58
+local mg_name = minetest.get_mapgen_setting("mg_name")
+if mg_name ~= "flat" then
+	-- 1 flat bedrock layer with 4 rough layers above
+	mcl_vars.bedrock_overworld_min = -62
+	mcl_vars.bedrock_overworld_max = mcl_vars.bedrock_overworld_min + 4
+	mcl_vars.bedrock_is_rough = true
+else
+	-- 1 perfectly flat bedrock layer
+	local ground = minetest.get_mapgen_setting("mgflat_ground_level")
+	mcl_vars.bedrock_overworld_min = ground - 3
+	mcl_vars.bedrock_overworld_max = mcl_vars.bedrock_overworld_min
+	mcl_vars.bedrock_is_rough = false
+end
 
 -- Set default stack sizes
 minetest.nodedef_default.stack_max = 64
diff --git a/mods/MAPGEN/mcl_biomes/init.lua b/mods/MAPGEN/mcl_biomes/init.lua
index 7342122e9..fc06e4589 100644
--- a/mods/MAPGEN/mcl_biomes/init.lua
+++ b/mods/MAPGEN/mcl_biomes/init.lua
@@ -1,11 +1,25 @@
 
 --
--- Register biomes
+-- Register biomes for mapgens other than v6
 -- EXPERIMENTAL!
 --
 
--- All mapgens except mgv6 and singlenode
+local function register_classic_superflat_biome()
+	-- Classic Superflat: bedrock (not part of biome), 2 dirt, 1 grass block
+	minetest.register_biome({
+		name = "flat",
+		node_top = "mcl_core:dirt_with_grass",
+		depth_top = 1,
+		node_filler = "mcl_core:dirt",
+		depth_filler = 2,
+		y_min = 1,
+		y_max = 31000,
+		heat_point = 50,
+		humidity_point = 50,
+	})
+end
 
+-- All mapgens except mgv6, flat and singlenode
 local function register_biomes()
 
 	minetest.register_biome({
@@ -227,7 +241,10 @@ end
 -- Detect mapgen to select functions
 --
 local mg_name = minetest.get_mapgen_setting("mg_name")
-if mg_name ~= "v6" then
+if mg_name ~= "v6" and mg_name ~= "flat" then
 	register_biomes()
 	register_decorations()
+elseif mg_name == "flat" then
+	-- Implementation of Minecraft's Superflat mapgen, classic style
+	register_classic_superflat_biome()
 end
diff --git a/mods/MAPGEN/mcl_mapgen_core/init.lua b/mods/MAPGEN/mcl_mapgen_core/init.lua
index 629385009..c6bafcfc2 100644
--- a/mods/MAPGEN/mcl_mapgen_core/init.lua
+++ b/mods/MAPGEN/mcl_mapgen_core/init.lua
@@ -466,7 +466,7 @@ minetest.register_on_generated(function(minp, maxp, seed)
 end)
 
 
--- Generate 5 layers of bedrock, with increasing levels of roughness, until a perfecly flat bedrock later at the bottom layer
+-- Generate bedrock layer or layers
 local BEDROCK_MIN = mcl_vars.bedrock_overworld_min
 local BEDROCK_MAX = mcl_vars.bedrock_overworld_max
 
@@ -486,23 +486,34 @@ minetest.register_on_generated(function(minp, maxp)
 				for z = minp.z, maxp.z do
 					local p_pos = area:index(x, y, z)
 					local setdata = nil
-					if y == BEDROCK_MAX then
-						-- 50% bedrock chance
-						if math.random(1,2) == 1 then setdata = c_bedrock end
-					elseif y == BEDROCK_MAX -1 then
-						-- 66.666...%
-						if math.random(1,3) <= 2 then setdata = c_bedrock end
-					elseif y == BEDROCK_MAX -2 then
-						-- 75%
-						if math.random(1,4) <= 3 then setdata = c_bedrock end
-					elseif y == BEDROCK_MAX -3 then
-						-- 90%
-						if math.random(1,10) <= 9 then setdata = c_bedrock end
-					elseif y == BEDROCK_MAX -4 then
-						-- 100%
-						setdata = c_bedrock
-					elseif y < BEDROCK_MIN then
-						setdata = c_void
+					if mcl_vars.bedrock_is_rough then
+						-- Bedrock layers with increasing levels of roughness, until a perfecly flat bedrock later at the bottom layer
+						-- This code assumes a bedrock height of 5 layers.
+						if y == BEDROCK_MAX then
+							-- 50% bedrock chance
+							if math.random(1,2) == 1 then setdata = c_bedrock end
+						elseif y == BEDROCK_MAX -1 then
+							-- 66.666...%
+							if math.random(1,3) <= 2 then setdata = c_bedrock end
+						elseif y == BEDROCK_MAX -2 then
+							-- 75%
+							if math.random(1,4) <= 3 then setdata = c_bedrock end
+						elseif y == BEDROCK_MAX -3 then
+							-- 90%
+							if math.random(1,10) <= 9 then setdata = c_bedrock end
+						elseif y == BEDROCK_MAX -4 then
+							-- 100%
+							setdata = c_bedrock
+						elseif y < BEDROCK_MIN then
+							setdata = c_void
+						end
+					else
+						-- Perfectly flat bedrock layer(s)
+						if y >= BEDROCK_MIN and y <= BEDROCK_MAX then
+							setdata = c_bedrock
+						elseif y < BEDROCK_MIN then
+							setdata = c_void
+						end
 					end
 					if setdata then
 						data[p_pos] = setdata