From e9e588a104c12f4c118b3873da30d15ca6c755e8 Mon Sep 17 00:00:00 2001
From: Wuzzy <almikes@aol.com>
Date: Sat, 1 Apr 2017 17:01:15 +0200
Subject: [PATCH] Add top snow on v6-generated snowy grass blocks

---
 mods/MAPGEN/mcl_mapgen_core/init.lua | 56 ++++++++++++++++++++--------
 1 file changed, 40 insertions(+), 16 deletions(-)

diff --git a/mods/MAPGEN/mcl_mapgen_core/init.lua b/mods/MAPGEN/mcl_mapgen_core/init.lua
index 27a742ee60..d3d8601683 100644
--- a/mods/MAPGEN/mcl_mapgen_core/init.lua
+++ b/mods/MAPGEN/mcl_mapgen_core/init.lua
@@ -799,6 +799,17 @@ local function register_mgv6_decorations()
 
 end
 
+-- Apply mapgen-specific mapgen code
+local mg_name = minetest.get_mapgen_setting("mg_name")
+if mg_name == "v6" then
+	register_mgv6_decorations()
+end
+if mg_name == "flat" then
+	minetest.set_mapgen_setting("mg_flags", "nocaves,nodungeons,nodecorations,light", true)
+else
+	minetest.set_mapgen_setting("mg_flags", "caves,nodungeons,decorations,light", true)
+end
+
 minetest.register_on_generated(function(minp, maxp, seed)
 	if maxp.y >= 2 and minp.y <= 0 then
 		-- Generate clay
@@ -924,15 +935,28 @@ local BEDROCK_MAX = mcl_vars.mg_bedrock_overworld_max
 -- Below the bedrock, generate air/void
 
 minetest.register_on_generated(function(minp, maxp)
+	local vm, emin, emax = minetest.get_mapgen_object("voxelmanip")
+	local data = vm:get_data()
+	local area = VoxelArea:new({MinEdge=emin, MaxEdge=emax})
+
 	-- Generate bedrock layers
-	if minp.y <= BEDROCK_MAX then
-		local vm, emin, emax = minetest.get_mapgen_object("voxelmanip")
-		local data = vm:get_data()
-		local area = VoxelArea:new({MinEdge=emin, MaxEdge=emax})
+	if minp.y <= BEDROCK_MAX or mg_name == "v6" then
+		lvm = true
 		local c_bedrock = minetest.get_content_id("mcl_core:bedrock")
 		local c_void = minetest.get_content_id("mcl_core:void")
 
-		for y = minp.y, math.min(maxp.y, BEDROCK_MAX) do
+		local max_y
+		if mg_name == "v6" then
+			local c_grass_block_snow = minetest.get_content_id("mcl_core:dirt_with_grass_snow")
+			local c_grass_block = minetest.get_content_id("mcl_core:dirt_with_grass")
+			local c_snow = minetest.get_content_id("mcl_core:snow")
+			local c_air = minetest.get_content_id("air")
+			max_y = maxp.y
+		else
+			max_y = math.min(maxp.y, BEDROCK_MAX)
+		end
+
+		for y = minp.y, max_y do
 			for x = minp.x, maxp.x do
 				for z = minp.z, maxp.z do
 					local p_pos = area:index(x, y, z)
@@ -966,13 +990,22 @@ minetest.register_on_generated(function(minp, maxp)
 							setdata = c_void
 						end
 					end
+
 					if setdata then
 						data[p_pos] = setdata
 					end
+
+					-- Add top snow on exposed snowy grass blocks generated by the v6 mapgen
+					-- FIXME: Does this work on chunk borders?
+					if mg_name == "v6" then
+						local p_pos_above = area:index(x, y+1, z)
+						if p_pos_above and data[p_pos] == c_grass_block_snow and data[p_pos_above] == c_air then
+							data[p_pos_above] = c_snow
+						end
+					end
 				end
 			end
 		end
-
 		vm:set_data(data)
 		vm:calc_lighting()
 		vm:update_liquids()
@@ -1001,13 +1034,4 @@ minetest.register_on_generated(function(minp, maxp)
 	end
 end)
 
--- Apply mapgen-specific mapgen code
-local mg_name = minetest.get_mapgen_setting("mg_name")
-if mg_name == "v6" then
-	register_mgv6_decorations()
-end
-if mg_name == "flat" then
-	minetest.set_mapgen_setting("mg_flags", "nocaves,nodungeons,nodecorations,light", true)
-else
-	minetest.set_mapgen_setting("mg_flags", "caves,nodungeons,decorations,light", true)
-end
+