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mods/minetest_game/spawn/README.txt

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+Minetest Game mod: spawn
+========================
+See license.txt for license information.
+
+Authors of source code
+----------------------
+paramat (MIT)

mods/minetest_game/spawn/api.lua

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+spawn = {}
+
+-- provide empty default implementations
+
+function spawn.get_default_pos()
+	return nil
+end
+
+function spawn.add_suitable_biome(biome)
+end
+
+-- Callback registration
+
+spawn.registered_on_spawn = {}
+
+function spawn.register_on_spawn(func)
+	table.insert(spawn.registered_on_spawn, func)
+end
+
+-- Logic run on spawn
+
+local use_engine_spawn = minetest.settings:get("static_spawnpoint") or
+		minetest.settings:get_bool("engine_spawn")
+
+local function on_spawn(player, is_new)
+	-- Ask all callbacks first
+	for _, cb in ipairs(spawn.registered_on_spawn) do
+		if cb(player, is_new) then
+			return true
+		end
+	end
+	-- Fall back to default spawn
+	if not use_engine_spawn then
+		local pos = spawn.get_default_pos()
+		if pos then
+			player:set_pos(pos)
+			return true
+		end
+	end
+	return false
+end
+
+minetest.register_on_newplayer(function(player)
+	on_spawn(player, true)
+end)
+
+minetest.register_on_respawnplayer(function(player)
+	return on_spawn(player, false)
+end)

mods/minetest_game/spawn/init.lua

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+-- Always load the API
+----------------------
+dofile(minetest.get_modpath(minetest.get_current_modname()) .. "/api.lua")
+
+-- Disable biome-search implementation on unsuitable mapgens
+------------------------------------------------------------
+
+local mg_name = minetest.get_mapgen_setting("mg_name")
+if mg_name == "v6" or mg_name == "singlenode" then
+	return
+end
+
+
+-- Parameters
+-------------
+
+-- Resolution of search grid in nodes.
+local res = 64
+-- Number of points checked in the square search grid (edge * edge).
+local checks = 128 * 128
+-- Starting point for biome checks. This also sets the y co-ordinate for all
+-- points checked, so the suitable biomes must be active at this y.
+local pos = {x = 0, y = 8, z = 0}
+
+
+-- Table of suitable biomes and matching API function
+
+local biome_ids = {}
+
+function spawn.add_suitable_biome(biome)
+	local id = minetest.get_biome_id(biome)
+	assert(id ~= nil)
+	biome_ids[id] = true
+end
+
+for _, name in ipairs({
+	"taiga", "coniferous_forest", "deciduous_forest", "grassland", "savanna"
+}) do
+	local id = minetest.get_biome_id(name)
+	if id then
+		biome_ids[id] = true
+	end
+end
+
+-- End of parameters
+--------------------
+
+-- Direction table
+
+local dirs = {
+	vector.new(0, 0, 1),
+	vector.new(-1, 0, 0),
+	vector.new(0, 0, -1),
+	vector.new(1, 0, 0),
+}
+
+
+-- Initial variables
+
+local edge_len = 1
+local edge_dist = 0
+local dir_step = 0
+local dir_ind = 1
+local searched = false
+local success = false
+local spawn_pos = {}
+
+
+-- Get world 'mapgen_limit' and 'chunksize' to calculate 'spawn_limit'.
+-- This accounts for how mapchunks are not generated if they or their shell exceed
+-- 'mapgen_limit'.
+
+local mapgen_limit = tonumber(minetest.get_mapgen_setting("mapgen_limit"))
+local chunksize = tonumber(minetest.get_mapgen_setting("chunksize"))
+local spawn_limit = math.max(mapgen_limit - (chunksize + 1) * 16, 0)
+
+
+-- Functions
+------------
+
+-- Get next position on square search spiral
+
+local function next_pos()
+	if edge_dist == edge_len then
+		edge_dist = 0
+		dir_ind = dir_ind + 1
+		if dir_ind == 5 then
+			dir_ind = 1
+		end
+		dir_step = dir_step + 1
+		edge_len = math.floor(dir_step / 2) + 1
+	end
+
+	local dir = dirs[dir_ind]
+	local move = vector.multiply(dir, res)
+
+	edge_dist = edge_dist + 1
+
+	return vector.add(pos, move)
+end
+
+
+-- Spawn position search
+
+local function search()
+	for iter = 1, checks do
+		local biome_data = minetest.get_biome_data(pos)
+		-- Sometimes biome_data is nil
+		if biome_data and biome_ids[biome_data.biome] then
+			local spawn_y = minetest.get_spawn_level(pos.x, pos.z)
+			if spawn_y then
+				spawn_pos = vector.new(pos.x, spawn_y, pos.z)
+				return true
+			end
+		end
+
+		pos = next_pos()
+		-- Check for position being outside world edge
+		if math.abs(pos.x) > spawn_limit or math.abs(pos.z) > spawn_limit then
+			return false
+		end
+	end
+
+	return false
+end
+
+
+function spawn.get_default_pos()
+	-- Search for spawn position once per server session
+	if not searched then
+		success = search()
+		searched = true
+	end
+	return success and spawn_pos
+end

mods/minetest_game/spawn/license.txt

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+License of source code
+----------------------
+
+The MIT License (MIT)
+Copyright (C) 2018 paramat
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this
+software and associated documentation files (the "Software"), to deal in the Software
+without restriction, including without limitation the rights to use, copy, modify, merge,
+publish, distribute, sublicense, and/or sell copies of the Software, and to permit
+persons to whom the Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or
+substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
+FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.
+
+For more details:
+https://opensource.org/licenses/MIT

mods/minetest_game/spawn/mod.conf

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+name = spawn
+description = Minetest Game mod: spawn
+depends = default