Update README.md

README.md

@@ -1,10 +1,27 @@
-Nether Mod for Minetest, with Portals API.
+# Nether Mod for Minetest, with Portals API.
+
+Enables Nether portals to be built, opening a gateway between the surface
+realm and one of lava and netherrack, with rumors of a passageway to a great
+magma ocean.
+
+To view the options provided by this mod, see settingtypes.txt or
+go to "Settings"->"All Settings"->"Mods"->"nether" in the game.
+
+A Nether portal is built as a rectangular vertical frame of obsidian, 4 blocks
+wide and 5 blocks high. Once constructed, a Mese crystal fragment can be
+right-click/used on the frame to activate it.
+
+
+## Modders and game designers
 
 See portal_api.txt for how to create custom portals to your own realms.
 
-See settingtypes.txt or go to "Settings"->"All Settings"->"Mods"->"nether"
-in the game to view the options provided by this mod.
-
+This mod provides Nether basalts (natural, hewn, and chiseled) as nodes which
+require a player to journey to the magma ocean to obtain, so these can be used
+for gating progression through a game. For example, a portal to another realm
+might need to be constructed from basalt, thus requiring a journey through
+the nether first, or basalt might be a crafting ingredient required to reach
+a particular branch of the tech-tree.
 
 ## License of source code:
 

mapgen.lua

@@ -161,7 +161,7 @@ minetest.register_node("nether:native_mapgen", {})
 minetest.register_biome({
 	name = "nether_caverns",
 	node_stone  = "nether:native_mapgen", -- nether:native_mapgen is used here to prevent the native mapgen from placing ores and decorations.
-	node_filler = "nether:native_mapgen", -- The lua on_generate will transform nether:rack_native into nether:rack then decorate and add ores.
+	node_filler = "nether:native_mapgen", -- The lua on_generate will transform nether:native_mapgen into nether:rack then decorate and add ores.
 	node_dungeon = "nether:brick",
 	node_dungeon_alt = "nether:brick_cracked",
 	node_dungeon_stair = "stairs:stair_nether_brick",
@@ -525,7 +525,7 @@ local function on_generated(minp, maxp, seed)
 
 	for y = y0, y1 do -- Y loop first to minimise tcave & lava-sea calculations
 
-		local sea_level, cavern_limit_distance = mapgen.find_nearest_lava_sealevel(y)
+		local sea_level, cavern_limit_distance = mapgen.find_nearest_lava_sealevel(y) -- function provided by mapgen_mantle.lua
 		local above_lavasea = y > sea_level
 		local below_lavasea = y < sea_level
 
@@ -534,7 +534,7 @@ local function on_generated(minp, maxp, seed)
 		local tmantle = CENTER_REGION_LIMIT + centerRegionLimit_adj -- cavern_noise_adj already contains central_region_limit_adj, so tmantle is only for comparisons when cavern_noise_adj hasn't been added to the noise value
 		local cavern_noise_adj =
 			CENTER_REGION_LIMIT * (cavern_limit_distance * cavern_limit_distance * cavern_limit_distance) -
-			centerRegionLimit_adj -- cavern_noise_adj gets added to noise value instead of added to the limit np_noise is compared against, so subtract centerRegionLimit_adj so subtract centerRegionLimit_adj instead of adding
+			centerRegionLimit_adj -- cavern_noise_adj gets added to noise value instead of added to the limit np_noise is compared against, so subtract centerRegionLimit_adj instead of adding
 
 		for z = z0, z1 do
 			local vi = area:index(x0, y, z) -- Initial voxelmanip index
@@ -548,7 +548,7 @@ local function on_generated(minp, maxp, seed)
 				if cave_noise > tcave then
 					-- Prime region
 					-- This was the only region in initial versions of the Nether mod.
-					-- It is the only region that portals from the surface will open into.
+					-- It is the only region which portals from the surface will open into.
 					data[vi] = c_air
 					contains_nether = true
 

mapgen_mantle.lua

@@ -286,7 +286,7 @@ function excavate_pathway(data, area, nether_pos, center_pos, minp, maxp)
 	radiusLimit = math_min(radiusLimit, vector_min(vector.subtract(maxp, stopPos)))
 
 	if radiusLimit < 4 then -- This is a logic check, ignore it. It could be commented out
-		-- 4 is (79 - 75), and shouldn't be possible if sampling-skip was 10
+		-- 4 is (79 - 75), and values less than 4 shouldn't be possible if sampling-skip was 10
 		-- i.e. if sampling-skip was 10 then {5, 15, 25, 35, 45, 55, 65, 75} should be sampled from possible positions 0 to 79
 		debugf("Error: radiusLimit %s is smaller then half the sampling distance. min %s, max %s, start %s, stop %s", radiusLimit, minp, maxp, startPos, stopPos)
 	end
@@ -304,7 +304,7 @@ function excavate_pathway(data, area, nether_pos, center_pos, minp, maxp)
 		local sizeAdj = 1 - (distFromMiddle * distFromMiddle * distFromMiddle)
 
 		local radius = math_min(radiusLimit, math.random(50 - (25 * sizeAdj), 80 - (45 * sizeAdj)) / 10)
-		local radiusCubed = radius * radius
+		local radiusSquared = radius * radius
 		local radiusCeil = math_floor(radius + 0.5)
 
 		linedata[i].radius = radius             -- Needed in third pass
@@ -315,7 +315,7 @@ function excavate_pathway(data, area, nether_pos, center_pos, minp, maxp)
 			local vi_z = vi + z * zstride
 			for y = -radiusCeil, radiusCeil do
 				local vi_zy = vi_z + y * ystride
-				local xSquaredLimit = radiusCubed - (z * z + y * y)
+				local xSquaredLimit = radiusSquared - (z * z + y * y)
 				for x = -radiusCeil, radiusCeil do
 					if x * x < xSquaredLimit then
 						data[vi_zy + x] = c_air
@@ -327,7 +327,7 @@ function excavate_pathway(data, area, nether_pos, center_pos, minp, maxp)
 	end
 
 	-- Third pass: decorate
-	-- Add glowstones to make tunnels to the mantle easyier to find
+	-- Add glowstones to make tunnels to the mantle easier to find
 	-- https://i.imgur.com/sRA28x7.jpg
 	for i = start_index, stop_index, 3 do
 		if linedata[i].distFromEnds < 0.3 then

portal_api.txt

@@ -22,6 +22,9 @@ one kind of portal with the same frame material — such as obsidian — provide
 the size of the PortalShape is distinct from any other type of portal that is
 using the same node for its frame, and portal sizes remain small.
 
+The Nether provides three variants of Nether basalt to ensure there are
+alternatives to obsidian for other mods to use as portalstones.
+
 
 Realms
 ------