Add 'compatibility' of https://notabug.org/minenux/minetest-mod-nssb for layer map

* add compatibilty backguard for minetest older engines 0.4.15+ to 4.0.X
* also detect loop optimization on newer ones to future reduce of lag
  so we can leave the older list of minerals be into a some pile of nodes
* fixed part of https://notabug.org/TenPlus1/nssb/issues/2
  a complete fix will need a configuration flag to let some ore on generation
* reason: optimized ore generation by removing iterations and using stratum feature
  as note this feature are only from 5.0 as documented and check in
  9f6d90aa81
  this was a good move by tenplus cos works as a unique plain layer due
  creates single undulating ore stratum that is continuous across mapchunk
  borders and horizontally spans the world, as a layer..
  the ore type its used only on the generation of the space of the 7 layers
  that defines the morlendor space, before and after there are indestructible ones
* then: make a loop for but if a 5.0 engine its detected break and
  do not loop innecesary, only loop and do scatter ore type for older engine
  so if newer one break loop and do stratum ore type generation for layers
* fix and close https://codeberg.org/minenux/minetest-mod-nssb/issues/3
* fix and close https://notabug.org/TenPlus1/nssb/issues/2

init.lua

@@ -2,6 +2,8 @@ nssb = {}
 
 local path = minetest.get_modpath("nssb")
 
+nssb.is_50 = minetest.has_feature("object_use_texture_alpha") or nil
+
 dofile(path .. "/nodes.lua")
 dofile(path .. "/mapgen.lua")
 dofile(path .. "/spawn.lua")

mapgen.lua

@@ -1,7 +1,7 @@
 local moreores = minetest.get_modpath("moreores")
+local is_50 = nssb.is_50
 
 nssb.mymapgenis = tonumber(minetest.settings:get("mymapgenis")) or 7
-
 if nssb.mymapgenis ~= 6 and nssb.mymapgenis ~= 7 then
 	nssb.mymapgenis = 7
 end
@@ -15,6 +15,14 @@ local posplace = {x = 0, y = level - 93, z = 0}
 local posmemory = {x = 0, y = level - 92, z = 0}
 local postest = {x = 5, y = level - 91, z = 6}
 
+-- ore type generation
+local oretype_morlan_layer
+	if is_50 then
+		oretype_morlan_layer       = "stratum"
+	else
+		oretype_morlan_layer       = "scatter"
+	end
+
 function nssb_register_buildings(
 	build, -- name of the schematic
 	rand, -- 1/rand is the probability of the spawning of the schematic if the place found is acceptable
@@ -362,11 +370,9 @@ nssb_register_buildings ("blocobiggesthouse", 4, "default:stone", 0, "air",  0,
 -- This dimension is "divided" in in 7 layer.
 -- 1st layer is indistructible, made of indistructible morentir
 
--- for i = 1, 9 do
+for i = 1, 9 do
-
 	minetest.register_ore({
-		--ore_type       = "scatter",
+		ore_type       = oretype_morlan_layer,
-		ore_type       = "stratum",
 		ore            = "nssb:indistructible_morentir",
 		wherein        = {
 			"default:water_source","default:water_flowing","default:gravel",
@@ -388,15 +394,15 @@ nssb_register_buildings ("blocobiggesthouse", 4, "default:stone", 0, "air",  0,
 		y_min          = level - 44,
 		y_max          = level - 37
 	})
--- end
+	if is_50 then break end
+end
 
 --[[
 if moreores then
 
 	for i = 1, 9 do
-
 		minetest.register_ore({
-			ore_type       = "scatter",
+			ore_type       = oretype_morlan_layer,
 			ore            = "nssb:indistructible_morentir",
 			wherein        = {
 				"moreores:mineral_tin", "moreores:mineral_silver",
@@ -409,18 +415,16 @@ if moreores then
 			y_max          = level - 37
 		})
 	end
+	if is_50 then break end
 end
 ]]
 
 -- 2nd layer is "stalagmitic", have bats and morelentir
 
 local function replace2(old, new)
-
+	for i = 1, 9 do
---	for i = 1, 9 do
-
 		minetest.register_ore({
-			-- ore_type       = "scatter",
+			ore_type       = oretype_morlan_layer,
-			ore_type       = "stratum",
 			ore            = new,
 			wherein        = old,
 			clust_scarcity = 1,
@@ -429,7 +433,8 @@ local function replace2(old, new)
 			y_min          = level - 65,
 			y_max          = level - 45
 		})
---	end
+		if is_50 then break end
+	end
 end
 
 -- optimized list
@@ -493,7 +498,6 @@ minetest.register_ore({
 })
 
 for i = 1, 3 do
-
 	minetest.register_ore({
 		ore_type       = "scatter",
 		ore            = "air",
@@ -504,15 +508,14 @@ for i = 1, 3 do
 		y_min          = level - 66,
 		y_max          = level - 58
 	})
+	if is_50 then break end
 end
 
 -- 3rd layer is made by air
 
---for i = 1, 32 do
+for i = 1, 32 do
-
 	minetest.register_ore({
-		--ore_type       = "scatter",
+		ore_type       = oretype_morlan_layer,
-		ore_type       = "stratum",
 		ore            = "air",
 		wherein        = {
 			"nssb:ant_dirt", "default:stone", "default:cobble", "default:stonebrick",
@@ -533,15 +536,15 @@ end
 		y_min          = level - 93,
 		y_max          = level - 66
 	})
---end
+	if is_50 then break end
+end
 
 --[[
 if moreores then
 
 	for i = 1, 9 do
-
 		minetest.register_ore({
-			ore_type       = "scatter",
+			ore_type       = oretype_morlan_layer,
 			ore            = "air",
 			wherein        = {
 				"moreores:mineral_tin", "moreores:mineral_silver",
@@ -553,6 +556,7 @@ if moreores then
 			y_min          = level - 93,
 			y_max          = level - 66
 		})
+		if is_50 then break end
 	end
 end
 ]]
@@ -694,11 +698,9 @@ minetest.register_ore({
 
 local function replace4(old, new)
 
---	for i = 1, 9 do
+	for i = 1, 9 do
-
 		minetest.register_ore({
-			--ore_type       = "scatter",
+			ore_type       = oretype_morlan_layer,
-			ore_type       = "stratum",
 			ore            = new,
 			wherein        = old,
 			clust_scarcity = 1,
@@ -707,7 +709,8 @@ local function replace4(old, new)
 			y_min          = level - 107,
 			y_max          = level - 94
 		})
---	end
+		if is_50 then break end
+	end
 end
 
 -- optimized list
@@ -790,11 +793,9 @@ minetest.register_ore({
 
 local function replace5(old, new)
 
---	for i = 1, 9 do
+	for i = 1, 9 do
-
 		minetest.register_ore({
-			-- ore_type       = "scatter",
+			ore_type       = oretype_morlan_layer,
-			ore_type       = "stratum",
 			ore            = new,
 			wherein        = old,
 			clust_scarcity = 1,
@@ -803,7 +804,8 @@ local function replace5(old, new)
 			y_min          = level - 156,
 			y_max          = level - 108
 		})
---	end
+		if is_50 then break end
+	end
 end
 
 minetest.register_ore({
@@ -874,11 +876,10 @@ end
 
 local function replace6(old, new)
 
---	for i = 1, 9 do
+	for i = 1, 9 do
 
 		minetest.register_ore({
-			-- ore_type       = "scatter",
+			ore_type       = oretype_morlan_layer,
-			ore_type       = "stratum",
 			ore            = new,
 			wherein        = old,
 			clust_scarcity = 1,
@@ -887,7 +888,8 @@ local function replace6(old, new)
 			y_min          = level - 205,
 			y_max          = level - 157
 		})
---	end
+		if is_50 then break end
+	end
 end
 
 -- optimized list
@@ -948,11 +950,10 @@ minetest.register_ore({
 
 -- 7th layer is indistructible
 
--- for i = 1, 9 do
+for i = 1, 9 do
 
 	minetest.register_ore({
-		-- ore_type       = "scatter",
+		ore_type       = oretype_morlan_layer,
-		ore_type       = "stratum",
 		ore            = "nssb:indistructible_morentir",
 		wherein        = {
 			"nssb:ant_dirt", "default:stone", "default:cobble", "default:stonebrick",
@@ -972,7 +973,8 @@ minetest.register_ore({
 		y_min          = level - 213,
 		y_max          = level - 206
 	})
--- end
+	if is_50 then break end
+end
 
 --[[
 if moreores then
@@ -980,7 +982,7 @@ if moreores then
 	for i = 1, 9 do
 
 		minetest.register_ore({
-			ore_type       = "scatter",
+			ore_type       = oretype_morlan_layer,
 			ore            = "nssb:indistructible_morentir",
 			wherein        = {
 				"moreores:mineral_tin", "moreores:mineral_silver",
@@ -992,15 +994,15 @@ if moreores then
 			y_min          = level - 213,
 			y_max          = level - 206
 		})
+		if is_50 then break end
 	end
 end
 ]]
 
--- for i = 1, 12 do
+for i = 1, 12 do
 
 	minetest.register_ore({
-		-- ore_type       = "scatter",
+		ore_type       = oretype_morlan_layer,
-		ore_type       = "stratum",
 		ore            = "air",
 		wherein        = {
 			"default:water_source", "default:water_flowing", "default:lava_source",
@@ -1012,7 +1014,8 @@ end
 		y_min          = level - 207,
 		y_max          = level - 45
 	})
--- end
+	if is_50 then break end
+end
 
 -- Place the buildings in the morlendor