Generate end portal rooms in the world

mods/MAPGEN/mcl_strongholds/depends.txt

@@ -0,0 +1,3 @@
+mcl_init
+mcl_structures
+mcl_mapgen_core

mods/MAPGEN/mcl_strongholds/description.txt

@@ -0,0 +1 @@
+Generates strongholds with end portals in the Overworld

mods/MAPGEN/mcl_strongholds/init.lua

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+-- Generate strongholds.
+
+-- A total of 128 strongholds are generated in rings around the world origin.
+-- This is the list of rings, starting with the innermost ring first.
+local stronghold_rings = {
+	-- amount: Number of strongholds in ring.
+	-- min, max: Minimum and maximum distance from (X=0, Z=0).
+	{ amount = 3, min = 1408, max = 2688 },
+	{ amount = 6, min = 4480, max = 5760 },
+	{ amount = 10, min = 7552, max = 8832 },
+	{ amount = 15, min = 10624, max = 11904 },
+	{ amount = 21, min = 13696, max = 14976 },
+	{ amount = 28, min = 16768, max = 18048 },
+	{ amount = 36, min = 19840, max = 21120 },
+	{ amount = 9, min = 22912, max = 24192 },
+}
+
+local strongholds = {}
+local strongholds_inited = false
+
+local mg_name = minetest.get_mapgen_setting("mg_name")
+
+-- Determine the stronghold positions and store them into the strongholds table.
+-- The stronghold positions are based on the world seed.
+-- The actual position might be offset by a few blocks because it might be shifted
+-- to make sure the end portal room is completely within the boundaries of a mapchunk.
+local init_strongholds = function()
+	if strongholds_inited then
+		return
+	end
+	-- Don't generate strongholds in singlenode
+	if mg_name == "singlenode" then
+		strongholds_inited = true
+		return
+	end
+	local seed = tonumber(minetest.get_mapgen_setting("seed"))
+	local pr = PseudoRandom(seed)
+	for s=1, #stronghold_rings do
+		local ring = stronghold_rings[s]
+
+		-- Get random angle
+		local angle = pr:next()
+		-- Scale angle to 0 .. 2*math.pi
+		angle = (angle / 32767) * (math.pi*2)
+		for a=1, ring.amount do
+			local dist = pr:next(ring.min, ring.max)
+			local y
+			if mg_name == "flat" then
+				y = mcl_vars.mg_bedrock_overworld_max + pr:next(1, 4)
+			else
+				y = pr:next(mcl_vars.mg_bedrock_overworld_max+1, mcl_vars.mg_overworld_min+48)
+			end
+			local pos = { x = math.cos(angle) * dist, y = y, z = math.sin(angle) * dist }
+			pos = vector.round(pos)
+			table.insert(strongholds, { pos = pos })
+
+			-- Rotate angle by (360 / amount) degrees.
+			-- This will cause the angles to be evenly distributed in the stronghold ring
+			angle = math.fmod(angle + ((math.pi*2) / ring.amount), math.pi*2)
+		end
+	end
+	strongholds_inited = true
+end
+
+-- Stronghold generation for register_on_generated.
+local generate_strongholds = function(minp, maxp)
+	for s=1, #strongholds do
+		if not strongholds[s].generated then
+			local pos = strongholds[s].pos
+			if minp.x <= pos.x and maxp.x >= pos.x and minp.z <= pos.z and maxp.z >= pos.z and minp.y <= pos.y and maxp.y >= pos.y then
+				-- Make sure the end portal room is completely within the current mapchunk
+				-- The original pos is changed intentionally.
+				if pos.x - 6 < minp.x then
+					pos.x = minp.x + 7
+				end
+				if pos.x + 6 > maxp.x then
+					pos.x = maxp.x - 7
+				end
+				if pos.z - 6 < minp.z then
+					pos.z = minp.z + 7
+				end
+				if pos.z + 6 > maxp.z then
+					pos.z = maxp.z - 7
+				end
+
+				mcl_structures.call_struct(pos, "end_portal_room")
+				strongholds[s].generated = true
+			end
+		end
+	end
+end
+
+
+init_strongholds()
+
+--[[ Note this mod depends on mcl_mapgen_core to make sure the core mapgen runs FIRST.
+This is important because we need this to make sure the stronghold isn't instantly
+overwritten by the core mapgen (since it uses LuaVoxelManip). ]]
+minetest.register_on_generated(function(minp, maxp, blockseed)
+	generate_strongholds(minp, maxp)
+end)

mods/MAPGEN/mcl_strongholds/mod.conf

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+name = mcl_strongholds

mods/MAPGEN/mcl_structures/init.lua

@@ -127,13 +127,15 @@ end
 
 mcl_structures.generate_end_portal_room = function(pos)
 	local path = minetest.get_modpath("mcl_structures").."/schematics/mcl_structures_end_portal_room_simple.mts"
+	local offset = {x=6, y=8, z=6}
 	local size = {x=13, y=8, z=13}
-	local ret = minetest.place_schematic(pos, path, "0", nil, true)
+	local newpos = { x = pos.x - offset.x, y = pos.y, z = pos.z - offset.z }
+	local ret = minetest.place_schematic(newpos, path, "0", nil, true)
 	if ret == nil then
 		return ret
 	end
 
-	local area_start, area_end = {x=pos.x-size.x, y=pos.y, z=pos.z-size.z}, vector.add(pos, size)
+	local area_start, area_end = newpos, vector.add(newpos, size)
 	-- Find and setup spawner with silverfish
 	local spawners = minetest.find_nodes_in_area(area_start, area_end, "mcl_mobspawners:spawner")
 	for s=1, #spawners do