Add flat Nether; fix portals in flat world

mods/ITEMS/mcl_portals/portal_end.lua

@@ -6,6 +6,8 @@ local nobj_cave = nil
 local SPAWN_MIN = mcl_vars.mg_end_min+70
 local SPAWN_MAX = mcl_vars.mg_end_min+98
 
+local mg_name = minetest.get_mapgen_setting("mg_name")
+
 -- 3D noise
 
 local np_cave = {
@@ -169,7 +171,10 @@ local function build_end_portal(pos, target3)
 						minetest.remove_node(newp)
 					end
 				else
-					if minetest.get_node(newp).name == "air" then
+					-- Build obsidian platform if floating
+					local newp_below = table.copy(newp)
+					newp_below.y = newp.y - 1
+					if minetest.get_node(newp).name == "air" and minetest.get_node(newp_below).name == "air" then
 						minetest.set_node(newp, {name="mcl_core:obsidian"})
 					end
 
@@ -301,7 +306,11 @@ local function make_end_portal(pos)
 	local target3 = {x = p1.x, y = p1.y, z = p1.z}
 	target3.x = target3.x + 1
 	if target3.y < mcl_vars.mg_end_max and target3.y > mcl_vars.mg_end_min then
+		if mg_name == "flat" then
+			target3.y = mcl_vars.mg_bedrock_overworld_max + 5
+		else
 			target3.y = math.random(mcl_vars.mg_overworld_min + 40, mcl_vars.mg_overworld_min + 96)
+		end
 	else
 		target3.y = find_end_target3_y2(target3.x, target3.z)
 	end

mods/ITEMS/mcl_portals/portal_nether.lua

@@ -9,6 +9,8 @@ local FRAME_SIZE_Y_MIN = 5
 local FRAME_SIZE_X_MAX = 23
 local FRAME_SIZE_Y_MAX = 23
 
+local mg_name = minetest.get_mapgen_setting("mg_name")
+
 -- 3D noise
 local np_cave = {
 	offset = 0,
@@ -180,6 +182,9 @@ local function build_portal(pos, target, is_rebuilding)
 end
 
 local function find_nether_target_y(target_x, target_z)
+	if mg_name == "flat" then
+		return mcl_vars.mg_bedrock_nether_bottom_max + 5
+	end
 	local start_y = mcl_vars.mg_nether_min + math.random(38, 117) -- Search start
 	if not nobj_cave then
 		nobj_cave = minetest.get_perlin(np_cave)
@@ -306,7 +311,11 @@ local function make_portal(pos)
 	local target = {x = p1.x, y = p1.y, z = p1.z}
 	target.x = target.x + 1
 	if target.y < mcl_vars.mg_nether_max and target.y > mcl_vars.mg_nether_min then
+		if mg_name == "flat" then
+			target.y = mcl_vars.mg_bedrock_overworld_max + 5
+		else
 			target.y = math.random(mcl_vars.mg_overworld_min + 40, mcl_vars.mg_overworld_min + 96)
+		end
 	else
 		target.y = find_nether_target_y(target.x, target.z)
 	end

mods/MAPGEN/mcl_mapgen_core/init.lua

@@ -1307,9 +1307,11 @@ minetest.register_on_generated(function(minp, maxp)
 						end
 					end
 
+					-- Bedrock, defined above
 					if setdata then
 						data[p_pos] = setdata
 						lvm_used = true
+					-- The void
 					elseif mcl_util.is_in_void({x=x,y=y,z=z}) then
 						data[p_pos] = c_void
 						lvm_used = true
@@ -1341,6 +1343,10 @@ minetest.register_on_generated(function(minp, maxp)
 					elseif y >= mcl_vars.mg_realm_barrier_overworld_end_min and y <= mcl_vars.mg_realm_barrier_overworld_end_max then
 						data[p_pos] = c_realm_barrier
 						lvm_used = true
+					-- Flat Nether
+					elseif mg_name == "flat" and y >= mcl_vars.mg_bedrock_nether_bottom_max + 4 and y <= mcl_vars.mg_bedrock_nether_bottom_max + 52 then
+						data[p_pos] = c_air
+						lvm_used = true
 					-- Nether and End support for v6 because v6 does not support the biomes API
 					elseif mg_name == "v6" then
 						if y <= mcl_vars.mg_nether_max and y >= mcl_vars.mg_nether_min then