Add ores: rack with gold, deeprack with scattered mese (#90)

Refactor the function to use a while loop.
Remove useless recursive call causing freezing.

init.lua

@@ -144,7 +144,7 @@ if nether.NETHER_REALM_ENABLED then
 	end
 end
 dofile(nether.path .. "/portal_examples.lua")
-
+dofile(nether.path .. "/ores.lua")
 
 -- Portals are ignited by right-clicking with a mese crystal fragment
 nether.register_portal_ignition_item(

mapgen.lua

@@ -495,8 +495,13 @@ function nether.find_nether_ground_y(target_x, target_z, start_y, player_name)
 	local minp = {x = minp_schem.x, y = 0, z = minp_schem.z}
 	local maxp = {x = maxp_schem.x, y = 0, z = maxp_schem.z}
 
-	for y = start_y, math_max(NETHER_FLOOR + BLEND, start_y - 4096), -1 do
-		local nval_cave = nobj_cave_point:get_3d({x = target_x, y = y, z = target_z})
+	local sample_pos = vector.new(target_x, 0, target_z) -- reuse to avoid making new tables
+	local y = start_y
+	local limit_y = math_max(NETHER_FLOOR + BLEND, start_y - 4096)
+
+	while y >= limit_y do
+		sample_pos.y = y
+		local nval_cave = nobj_cave_point:get_3d(sample_pos)
 
 		if nval_cave > TCAVE then -- Cavern
 			air = air + 1
@@ -509,12 +514,14 @@ function nether.find_nether_ground_y(target_x, target_z, start_y, player_name)
 				if nether.volume_is_natural_and_unprotected(minp, maxp, player_name) then
 					return portal_y
 				else -- Restart search a little lower
-					nether.find_nether_ground_y(target_x, target_z, y - 16, player_name)
+					air = 0 -- space above is unsuitable
+					y = y - 16
 				end
 			else -- Not enough space, reset air to zero
 				air = 0
 			end
 		end
+		y = y - 1
 	end
 
 	return math_max(start_y, NETHER_FLOOR + BLEND) -- Fallback

ores.lua

@@ -0,0 +1,48 @@
+
+local S = minetest.get_translator("nether")
+
+
+minetest.register_node("nether:rack_with_gold", {
+	description = S("Nether Gold"),
+	tiles = {"nether_rack.png^default_mineral_gold.png"},
+	is_ground_content = true,
+	groups = {cracky = 3, level = 2, workable_with_nether_tools = 3, not_in_creative_inventory = 1},
+	drop = "default:gold_lump",
+	sounds = default.node_sound_stone_defaults()
+})
+
+minetest.register_node("nether:rack_deep_with_mese", {
+	description = S("Nether Mese"),
+	tiles = {"nether_rack_deep.png^default_mineral_mese.png"},
+	is_ground_content = true,
+	groups = {cracky = 3, level = 2, workable_with_nether_tools = 3, not_in_creative_inventory = 1},
+	drop = "default:mese_crystal_fragment 4",
+	sounds = default.node_sound_stone_defaults(),
+})
+
+
+local ore_ceiling = nether.DEPTH_CEILING - 128
+local ore_floor   = nether.DEPTH_FLOOR   + 128
+
+
+minetest.register_ore({
+	ore_type       = "scatter",
+	ore            = "nether:rack_with_gold",
+	wherein        = "nether:rack",
+	clust_scarcity = 15 * 15 * 15,
+	clust_num_ores = 7,
+	clust_size     = 5,
+	y_max          = ore_ceiling,
+	y_min          = ore_floor
+})
+
+minetest.register_ore({
+	ore_type       = "scatter",
+	ore            = "nether:rack_deep_with_mese",
+	wherein        = "nether:rack_deep",
+	clust_scarcity = 15 * 15 * 15,
+	clust_num_ores = 7,
+	clust_size     = 5,
+	y_max          = ore_ceiling,
+	y_min          = ore_floor,
+})