Added caves (hardcoded for now)

(latest version of biomegen)

gridio.lua

@@ -1,114 +0,0 @@
--- Input and output functions for grid maps
-
-local worldpath = mapgen_rivers.world_data_path
-
-local floor = math.floor
-local sbyte, schar = string.byte, string.char
-local unpk = unpack
-
--- Loading files
-local function load_full_map(filename, bytes, signed, size, converter)
-	local file = io.open(worldpath .. filename, 'rb')
-	local data = file:read('*all')
-	if #data < bytes*size then
-		data = minetest.decompress(data)
-	end
-
-	local map = {}
-
-	for i=1, size do
-		local i0 = (i-1)*bytes+1
-		local elements = {data:byte(i0, i1)}
-		local n = sbyte(data, i0)
-		if signed and n >= 128 then
-			n = n - 256
-		end
-
-		for j=1, bytes-1 do
-			n = n*256 + sbyte(data, i0+j)
-		end
-
-		map[i] = n
-	end
-	file:close()
-
-	if converter then
-		for i=1, size do
-			map[i] = converter(map[i])
-		end
-	end
-
-	return map
-end
-
-local loader_mt = {
-	__index = function(loader, i)
-		local file = loader.file
-		local bytes = loader.bytes
-		file:seek('set', (i-1)*bytes)
-		local strnum = file:read(bytes)
-
-		local n = sbyte(strnum, 1)
-		if loader.signed and n >= 128 then
-			n = n - 256
-		end
-
-		for j=2, bytes do
-			n = n*256 + sbyte(strnum, j)
-		end
-
-		if loader.conv then
-			n = loader.conv(n)
-		end
-		loader[i] = n
-		return n
-	end,
-}
-
-local function interactive_loader(filename, bytes, signed, size, converter)
-	local file = io.open(worldpath .. filename, 'rb')
-	if file then
-		converter = converter or false
-		return setmetatable({file=file, bytes=bytes, signed=signed, size=size, conv=converter}, loader_mt)
-	end
-end
-
-local load_methods = {
-	full        = load_full_map,
-	interactive = interactive_loader,
-}
-
-function mapgen_rivers.load_file(...)
-	local load_method = mapgen_rivers.settings.load_method
-	local load_func = load_methods[load_method]
-	if load_func then
-		return load_func(...)
-	else
-		minetest.log("error", ("[mapgen_rivers] Unknown load method %s"):format(load_method))
-	end
-end
-
--- Writing files
-function mapgen_rivers.write_file(filename, data, bytes)
-	local size = #data
-	local file = io.open(worldpath .. filename, 'wb')
-
-	local bytelist = {}
-	for j=1, bytes do
-		bytelist[j] = 0
-	end
-
-	for i=1, size do
-		local n = floor(data[i])
-		data[i] = n
-		for j=bytes, 2, -1 do
-			bytelist[j] = n % 256
-			n = floor(n / 256)
-		end
-		bytelist[1] = n % 256
-
-		file:write(schar(unpk(bytelist)))
-	end
-
-	file:close()
-end

gridmanager.lua

@@ -1,6 +1,6 @@
 -- Manages grid loading, writing and generation
 
-local world_data = mapgen_rivers.world_data_path
+local datapath = mapgen_rivers.world_data_path
 
 local registered_on_grid_loaded = {}
 function mapgen_rivers.register_on_grid_loaded(func)
@@ -21,128 +21,85 @@ local function offset_conv(o)
 	return (o + 0.5) * (1/256)
 end
 
-local grid_maps_list = {
-	dem = {bytes=2, signed=true},
-	lakes = {bytes=2, signed=true},
-	dirs = {bytes=1, signed=false},
-	rivers = {bytes=4, signed=false},
+local floor = math.floor
+local sbyte, schar = string.byte, string.char
+local unpk = unpack
 
-	offset_x = {bytes=1, signed=true, conv=offset_conv},
-	offset_y = {bytes=1, signed=true, conv=offset_conv},
+-- Loading files
+
+-- Never load the full map during mapgen. Instead, create an empty lookup table
+-- and read the file on-the-fly when an element is requested for the first time,
+-- using __index metamethod.
+local loader_mt = {
+	__index = function(loader, i) -- Called when accessing a missing key
+		local file = loader.file
+		local bytes = loader.bytes
+		file:seek('set', (i-1)*bytes)
+		local strnum = file:read(bytes)
+
+		local n = sbyte(strnum, 1)
+		if loader.signed and n >= 128 then
+			n = n - 256
+		end
+
+		for j=2, bytes do
+			n = n*256 + sbyte(strnum, j)
+		end
+
+		if loader.conv then
+			n = loader.conv(n)
+		end
+		-- Cache key for next use
+		loader[i] = n
+		return n
+	end,
 }
 
-local function apply_grid_conversion(grid)
-	if grid.load_method ~= "full" then
-		minetest.log("warning", ("Could not apply data conversion for load method %s"):format(grid.load_method))
-		return false
+local function load_file(filename, bytes, signed, size, converter)
+	local file = io.open(datapath .. filename, 'rb')
+	if file then
+		converter = converter or false
+		return setmetatable({file=file, bytes=bytes, signed=signed, size=size, conv=converter}, loader_mt)
 	end
-	if grid.conv_applied then
-		return true
-	end
-
-	local size = grid.size.x * grid.size.y
-	for mapname, params in pairs(grid_maps_list) do
-		local conv = params.conv
-		if conv then
-			local map = grid[mapname]
-			for i=1, size do
-				map[i] = conv(map[i])
-			end
-		end
-	end
-	grid.conv_applied = true
-
-	return true
 end
 
-function mapgen_rivers.try_load_grid(grid)
-	local load_method = mapgen_rivers.settings.load_method
-
-	-- First, check whether a grid is already loaded with the appropriate method
-	if mapgen_rivers.grid and mapgen_rivers.grid.load_method == load_method then
-		if not mapgen_rivers.grid.conv_applied then
-			apply_grid_conversion(mapgen_rivers.grid)
-		end
-		return true
-	-- Then, check the provided argument is a valid grid
-	elseif grid and grid.load_method == load_method then
-		if not mapgen_rivers.grid.conv_applied then
-			apply_grid_conversion(grid)
-		end
-		mapgen_rivers.grid = grid
-		on_grid_loaded_callback(grid)
+function mapgen_rivers.load_or_generate_grid()
+	-- First, check whether a grid is already loaded
+	if mapgen_rivers.grid then
 		return true
 	end
 
-	-- Fall back to loading the grid from the files
-	local sfile = io.open(world_data .. 'size', 'r')
+	-- If not, try to load the grid from the files
+	local sfile = io.open(datapath .. 'size', 'r')
+	if not sfile then
+		dofile(mapgen_rivers.modpath .. "/pregenerate.lua")
+		collectgarbage()
+
+		sfile = io.open(datapath .. 'size', 'r')
 		if not sfile then
 			return false
 		end
+	end
 
 	local x, z = sfile:read('*n'), sfile:read('*n')
 	if not x or not z then
 		return false
 	end
 
-	if load_method == "full" then
-		minetest.log("action", '[mapgen_rivers] Loading full grid')
-	elseif load_method == "interactive" then
-		minetest.log("action", '[mapgen_rivers] Loading grid as interactive loaders')
-	end
+	minetest.log("action", '[mapgen_rivers] Loading grid')
 
-	grid = {
-		load_method = load_method,
+	local grid = {
 		size = {x=x, y=z},
+		dem = load_file('dem', 2, true, x*z),
+		lakes = load_file('lakes', 2, true, x*z),
+		dirs = load_file('dirs', 1, false, x*z),
+		rivers = load_file('rivers', 4, false, x*z),
+		offset_x = load_file('offset_x', 1, true, x*z, offset_conv),
+		offset_y = load_file('offset_y', 1, true, x*z, offset_conv),
 	}
 
-	for map, params in pairs(grid_maps_list) do
-		grid[map] = mapgen_rivers.load_file(map, params.bytes, params.signed, x*z, params.conv)
-	end
-	grid.conv_applied = true
-
 	mapgen_rivers.grid = grid
 	on_grid_loaded_callback(grid)
 
 	return true
 end
-
-function mapgen_rivers.generate_grid()
-	minetest.log("action", '[mapgen_rivers] Generating grid, this may take a while...')
-	local grid = {}
-
-	local blocksize = mapgen_rivers.settings.blocksize
-	local xsize = math.floor(mapgen_rivers.settings.map_x_size / blocksize)
-	local zsize = math.floor(mapgen_rivers.settings.map_z_size / blocksize)
-	grid.size = {x=xsize, y=zsize}
-	grid.conv_applied = false
-
-	if not mapgen_rivers.pregenerate then
-		minetest.log("error", "[mapgen_rivers] Pre-generation function is not available.")
-		return false
-	end
-
-	mapgen_rivers.pregenerate(grid)
-
-	return grid
-end
-
-function mapgen_rivers.write_grid(grid)
-	minetest.mkdir(world_data)
-
-	if grid.conv_applied then
-		minetest.log("error", '[mapgen_rivers] Could not write grid if data conversion is already done')
-		return false
-	end
-
-	for map, params in pairs(grid_maps_list) do
-		mapgen_rivers.write_file(map, grid[map], params.bytes)
-	end
-
-	local sfile = io.open(world_data .. 'size', "w")
-	sfile:write(grid.size.x..'\n'..grid.size.y)
-	sfile:close()
-
-	return true
-end
-

init.lua

@@ -8,19 +8,9 @@ mapgen_rivers.world_data_path = minetest.get_worldpath() .. '/river_data/'
 
 dofile(modpath .. 'settings.lua')
 dofile(modpath .. 'gridmanager.lua')
-dofile(modpath .. 'gridio.lua')
 dofile(modpath .. 'polygons.lua')
 dofile(modpath .. 'heightmap.lua')
 dofile(modpath .. 'mapgen.lua')
+dofile(modpath .. 'spawn.lua')
 
-minetest.register_on_mods_loaded(function()
-	local exist = mapgen_rivers.try_load_grid()
-
-	if not exist then -- If grid does not exist yet, generate it
-		dofile(modpath .. 'pregenerate.lua')
-
-		local grid = mapgen_rivers.generate_grid()
-		mapgen_rivers.write_grid(grid)
-		mapgen_rivers.try_load_grid(grid) -- Reload if needed
-	end
-end)
+minetest.register_on_mods_loaded(mapgen_rivers.load_or_generate_grid)

mapgen.lua

@@ -28,12 +28,13 @@ local floor, min = math.floor, math.min
 
 local data = {}
 
-local noise_x_obj, noise_z_obj, noise_distort_obj, noise_heat_obj, noise_heat_blend_obj
+local noise_x_obj, noise_z_obj, noise_distort_obj, noise_heat_obj, noise_heat_blend_obj, noise_cave_obj
 local noise_x_map = {}
 local noise_z_map = {}
 local noise_distort_map = {}
 local noise_heat_map = {}
 local noise_heat_blend_map = {}
+local noise_cave = {}
 local mapsize
 local init = false
 
@@ -41,6 +42,18 @@ local sumtime = 0
 local sumtime2 = 0
 local ngen = 0
 
+local use_caves = true
+local np_cave = {
+	offset = 0,
+	scale = 8,
+	spread = {x=256, y=128, z=256},
+	seed = -9152,
+	octaves = 4,
+	persist = 0.65,
+	lacunarity = 2,
+	flags = "absvalue",
+}
+
 function mapgen_rivers.make_chunk(minp, maxp, seed)
 	minetest.log("info", ("[mapgen_rivers] Generating from %s to %s"):format(minetest.pos_to_string(minp), minetest.pos_to_string(maxp)))
 
@@ -65,6 +78,9 @@ function mapgen_rivers.make_chunk(minp, maxp, seed)
 			noise_heat_obj = minetest.get_perlin_map(mapgen_rivers.noise_params.heat, chulens)
 			noise_heat_blend_obj = minetest.get_perlin_map(mapgen_rivers.noise_params.heat_blend, chulens)
 		end
+		if use_caves then
+			noise_cave_obj = minetest.get_perlin_map(np_cave, mapsize)
+		end
 		init = true
 	end
 
@@ -79,7 +95,9 @@ function mapgen_rivers.make_chunk(minp, maxp, seed)
 		noise_heat_obj:get_2d_map_flat(minp2d, noise_heat_map)
 		noise_heat_blend_obj:get_2d_map_flat(minp2d, noise_heat_blend_map)
 	end
-
+	if use_caves then
+		noise_cave_obj:get_3d_map_flat(minp, noise_cave)
+	end
 	local terrain_map, lake_map, incr, i_origin
 
 	if use_distort then
@@ -103,6 +121,7 @@ function mapgen_rivers.make_chunk(minp, maxp, seed)
 				end
 				i2d = i2d-chulens.x
 			end
+			i2d = i2d+chulens.x
 		end
 
 		local pminp = {x=floor(xmin), z=floor(zmin)}
@@ -127,6 +146,10 @@ function mapgen_rivers.make_chunk(minp, maxp, seed)
 
 		-- If not, skip chunk
 		if is_empty then
+			if use_biomegen_mod and biomegen.skip_chunk then
+				biomegen.skip_chunk(minp, maxp)
+			end
+
 			local t = os.clock() - t0
 			ngen = ngen + 1
 			sumtime = sumtime + t
@@ -141,6 +164,7 @@ function mapgen_rivers.make_chunk(minp, maxp, seed)
 	local c_stone = minetest.get_content_id("mapgen_stone")
 	local c_water = minetest.get_content_id("mapgen_water_source")
 	local c_rwater = minetest.get_content_id("mapgen_river_water_source")
+	local c_air = minetest.get_content_id("air")
 
 	local c_dirt, c_lawn, c_dirtsnow, c_snow, c_sand, c_ice
 	if use_biomes then
@@ -173,7 +197,7 @@ function mapgen_rivers.make_chunk(minp, maxp, seed)
 			if use_biomes then
 				temperature = noise_heat_map[i2d]+noise_heat_blend_map[i2d]
 			end
-			local terrain, lake
+			local terrain, lake, caveness
 			if not use_distort then
 				terrain = terrain_map[i2d]
 				lake = lake_map[i2d]
@@ -195,6 +219,10 @@ function mapgen_rivers.make_chunk(minp, maxp, seed)
 					lake = min(lake_map[i0], lake_map[i1], lake_map[i2], lake_map[i3])
 				end
 
+				if use_caves then
+					noise_cave[nid] = noise_cave[nid] < math.min(math.max(terrain - y, 0), 100) ^ 0.5 / 10
+				end
+
 				if y <= maxp.y then
 
 					local is_lake = lake > terrain
@@ -244,10 +272,32 @@ function mapgen_rivers.make_chunk(minp, maxp, seed)
 	end
 
 	if use_biomegen_mod then
-		biomegen.generate_all(data, a, vm, minp, maxp, seed)
-	else
+		biomegen.generate_biomes(data, a, minp, maxp)
+	end
+	if use_caves then
+		local i = 1
+		for z=minp.z, maxp.z do
+			for y=minp.y, maxp.y do
+				local vi = a:index(minp.x, y, z)
+				for x=minp.x, maxp.x do
+					if noise_cave[i] then
+						data[vi] = c_air
+					end
+					i = i + 1
+					vi = vi + 1
+				end
+			end
+			i = i + chulens.x -- Skip etra row
+		end		
+	end
 	vm:set_data(data)
+	if use_biomegen_mod then
+		biomegen.place_all_decos(data, a, vm, minp, maxp, seed)
+	end
 	minetest.generate_ores(vm, minp, maxp)
+	if use_biomegen_mod then
+		vm:get_data(data)
+		biomegen.dust_top_nodes(data, a, vm, minp, maxp)
 	end
 
 	vm:set_lighting({day = 0, night = 0})
@@ -262,7 +312,9 @@ function mapgen_rivers.make_chunk(minp, maxp, seed)
 	minetest.log("verbose", ("[mapgen_rivers] Done in %5.3f s"):format(t))
 end
 
-minetest.register_on_generated(mapgen_rivers.make_chunk)
+-- Enforce first position in mapgen callbacks
+table.insert(minetest.registered_on_generateds, 1, mapgen_rivers.make_chunk)
+--minetest.register_on_generated(mapgen_rivers.make_chunk)
 
 minetest.register_on_shutdown(function()
 	local avg = sumtime / ngen

pregenerate.lua

@@ -1,6 +1,8 @@
 -- Generate the grid using terrainlib_lua
 -- Only called on first mapgen, if there is no grid yet
 
+-- Constants
+
 local EvolutionModel = dofile(mapgen_rivers.modpath .. '/terrainlib_lua/erosion.lua')
 local twist = dofile(mapgen_rivers.modpath .. '/terrainlib_lua/twist.lua')
 
@@ -21,6 +23,9 @@ local use_margin = mapgen_rivers.settings.margin
 local margin_width = mapgen_rivers.settings.margin_width / blocksize
 local margin_elev = mapgen_rivers.settings.margin_elev
 
+local X = math.floor(mapgen_rivers.settings.map_x_size / blocksize)
+local Y = math.floor(mapgen_rivers.settings.map_z_size / blocksize)
+
 local function margin(dem, width, elev)
 	local X, Y = dem.X, dem.Y
 	for i=1, width do
@@ -49,33 +54,34 @@ local function margin(dem, width, elev)
 	end
 end
 
-function mapgen_rivers.pregenerate(grid)
-	local size = grid.size
+-- Generate grid
 
-	if size.x * size.y > 4e6 then
+minetest.log("action", '[mapgen_rivers] Generating grid, this may take a while...')
+
+if X*Y > 4e6 then
 	minetest.log("warning", "[mapgen_rivers] You are going to generate a very large grid (>4M nodes). If you experience problems, you should increase blocksize or reduce map size.")
-	end
+end
 
-	local seed = tonumber(minetest.get_mapgen_setting("seed"))
-	np_base.seed = (np_base.seed or 0) + seed
+local seed = tonumber(minetest.get_mapgen_setting("seed"):sub(-10))
+np_base.seed = (np_base.seed or 0) + seed
 
-	local nobj_base = PerlinNoiseMap(np_base, {x=size.x, y=1, z=size.y})
+local nobj_base = PerlinNoiseMap(np_base, {x=X, y=1, z=Y})
 
-	local dem = nobj_base:get_3d_map_flat({x=0, y=0, z=0})
-	dem.X = size.x
-	dem.Y = size.y
+local dem = nobj_base:get_3d_map_flat({x=0, y=0, z=0})
+dem.X = X
+dem.Y = Y
 
-	if use_margin then
+if use_margin then
 	margin(dem, margin_width, margin_elev)
-	end
+end
 
-	local model = EvolutionModel(evol_params)
-	model.dem = dem
-	local ref_dem = model:define_isostasy(dem)
+local model = EvolutionModel(evol_params)
+model.dem = dem
+local ref_dem = model:define_isostasy(dem)
 
-	local tectonic_step = tectonic_speed * time_step
-	collectgarbage()
-	for i=1, niter do
+local tectonic_step = tectonic_speed * time_step
+collectgarbage()
+for i=1, niter do
 	minetest.log("info", "[mapgen_rivers] Iteration " .. i .. " of " .. niter)
 
 	model:diffuse(time_step)
@@ -92,25 +98,53 @@ function mapgen_rivers.pregenerate(grid)
 	end
 
 	collectgarbage()
-	end
-	model:flow()
+end
+model:flow()
 
-	local mfloor = math.floor
-	local mmin, mmax = math.min, math.max
-	local offset_x, offset_y = twist(model.dirs, model.rivers, 5)
-	for i=1, size.x*size.y do
+local mfloor = math.floor
+local mmin, mmax = math.min, math.max
+local unpk, schar = unpack, string.char
+local offset_x, offset_y = twist(model.dirs, model.rivers, 5)
+for i=1, X*Y do
 	offset_x[i] = mmin(mmax(offset_x[i]*256, -128), 127)
 	offset_y[i] = mmin(mmax(offset_y[i]*256, -128), 127)
+end
+
+-- Write data
+
+local datapath = mapgen_rivers.world_data_path
+minetest.mkdir(datapath)
+
+local sfile = io.open(datapath .. 'size', "w")
+sfile:write(X..'\n'..Y)
+sfile:close()
+
+local function write_file(filename, data, bytes)
+	local file = io.open(datapath .. filename, 'wb')
+
+	local bytelist = {}
+	for j=1, bytes do
+		bytelist[j] = 0
 	end
 
-	grid.dem = model.dem
-	grid.lakes = model.lakes
-	grid.dirs = model.dirs
-	grid.rivers = model.rivers
-	grid.offset_x = offset_x
-	grid.offset_y = offset_y
+	for i=1, #data do
+		local n = mfloor(data[i])
+		data[i] = n
+		for j=bytes, 2, -1 do
+			bytelist[j] = n % 256
+			n = mfloor(n / 256)
+		end
+		bytelist[1] = n % 256
 
-	grid.load_method = "full"
-	grid.conv_applied = false
-	collectgarbage()
+		file:write(schar(unpk(bytelist)))
+	end
+
+	file:close()
 end
+
+write_file('dem', model.dem, 2)
+write_file('lakes', model.lakes, 2)
+write_file('dirs', model.dirs, 1)
+write_file('rivers', model.rivers, 4)
+write_file('offset_x', offset_x, 1)
+write_file('offset_y', offset_y, 1)

settings.lua

@@ -109,13 +109,8 @@ mapgen_rivers.settings = {
 	tectonic_speed = def_setting('tectonic_speed', 'number'),
 	evol_time = def_setting('evol_time', 'number'),
 	evol_time_step = def_setting('evol_time_step', 'number'),
-
-	load_all = mtsettings:get_bool('mapgen_rivers_load_all')
 }
 
-mapgen_rivers.settings.load_method =
-		mapgen_rivers.settings.load_all and "full" or "interactive"
-
 mapgen_rivers.noise_params = {
 	base = def_setting("np_base", "noise"),
 	distort_x = def_setting("np_distort_x", "noise"),

settings_default.json

@@ -25,7 +25,6 @@
 	"tectonic_speed": 70,
 	"evol_time": 10,
 	"evol_time_step": 1,
-	"load_all": false,
 
 	"np_base": {
 		"offset": 0,

settingtypes.txt

@@ -70,11 +70,6 @@ mapgen_rivers_glacier_widening_factor (Glacier widening factor) float 8.0 1.0 20
 #    This results in mountains being more covered by snow.
 mapgen_rivers_elevation_chill (Elevation chill) float 0.25 0.0 5.0
 
-#    If enabled, loads all grid data in memory at init time.
-#    If disabled, data will be loaded on request and cached in memory.
-#    It's recommended to disable it for very large maps (> 2000 grid nodes or so)
-mapgen_rivers_load_all (Load all data in memory) bool false
-
 [Landscape evolution parameters]
 
 #    Modelled landscape evolution time, in arbitrary units

spawn.lua

@@ -0,0 +1,119 @@
+local np_distort_x = mapgen_rivers.noise_params.distort_x
+local np_distort_z = mapgen_rivers.noise_params.distort_z
+local np_distort_amplitude = mapgen_rivers.noise_params.distort_amplitude
+
+local nobj_distort_x, nobj_distort_z, nobj_distort_amplitude
+
+local sea_level = mapgen_rivers.settings.sea_level
+local distort = mapgen_rivers.settings.distort
+
+-- Linear interpolation
+local function interp(v00, v01, v11, v10, xf, zf)
+	local v0 = v01*xf + v00*(1-xf)
+	local v1 = v11*xf + v10*(1-xf)
+	return v1*zf + v0*(1-zf)
+end
+
+local function estimate_spawn_level(pos, use_distort)
+	local x, z = pos.x, pos.z
+	if distort and use_distort then
+		nobj_distort_x = nobj_distort_x or minetest.get_perlin(np_distort_x)
+		nobj_distort_z = nobj_distort_z or minetest.get_perlin(np_distort_z)
+		nobj_distort_amplitude = nobj_distort_amplitude or minetest.get_perlin(np_distort_amplitude)
+
+		local amplitude = nobj_distort_amplitude:get_2d({x=pos.x, y=pos.z})
+		x = x + nobj_distort_x:get_3d(pos)*amplitude
+		z = z + nobj_distort_z:get_3d(pos)*amplitude
+	end
+
+	local terrain, lakes = mapgen_rivers.make_heightmaps(
+		{x=math.floor(x),   z=math.floor(z)  },
+		{x=math.floor(x)+1, z=math.floor(z)+1}
+	)
+
+	local ex, ez = x % 1, z % 1
+	--local h = terrain[1]*(1-ex)*(1-ez) + terrain[2]*ex*(1-ez) + terrain[3]*(1-ex)*ez + terrain[4]*ex*ez
+	local h = interp(terrain[1], terrain[2], terrain[4], terrain[3], ex, ez)
+	local lake = math.min(lakes[1], lakes[2], lakes[3], lakes[4])
+
+	if h < lake or h <= sea_level then
+		return false, h
+	end
+
+	return true, h
+end
+
+local function get_spawn_level(x, z)
+	local pos = {x=x, z=z}
+	local suitable, y = estimate_spawn_level(pos, false)
+	if not suitable then
+		return
+	end
+
+	if not distort then
+		return math.floor(y) + 1
+	end
+
+	local low_bound = -math.huge
+	local high_bound = math.huge
+	local suitable_high = false
+
+	repeat
+		pos.y = math.max(math.min(math.floor(y+0.5), high_bound-1), low_bound+1)
+		suitable, y = estimate_spawn_level(pos, true)
+		if y > pos.y then
+			low_bound = pos.y
+		else
+			high_bound = pos.y
+			suitable_high = suitable
+		end
+	until high_bound - low_bound <= 1
+
+	if not suitable_high then
+		return
+	end
+
+	return high_bound + 1
+end
+minetest.get_spawn_level = get_spawn_level
+
+local rmax = 2000
+local function find_spawn_point(seed)
+	local level = get_spawn_level(0, 0)
+	if level then
+		return {x=0, y=level, z=0}
+	end
+
+	local pr = PcgRandom(seed or os.time())
+	local incr = 16
+	local r0 = 0
+
+	while r0 < rmax do
+		local r1 = r0 + incr
+		local r = pr:next(r0*r0+1, r1*r1) ^ 0.5
+		local a = pr:next() / 2147483648 * math.pi
+
+		local x = math.floor(math.cos(a) * r + 0.5)
+		local z = math.floor(math.sin(a) * r + 0.5)
+
+		level = get_spawn_level(x, z)
+		if level then
+			return {x=x, y=level, z=z}
+		end
+		r0 = r1
+	end
+end
+
+local function spawn_player(player)
+	if minetest.settings:get("static_spawnpoint") then
+		return
+	end
+
+	local spawn_point = find_spawn_point()
+	if spawn_point then
+		player:set_pos(spawn_point)
+	end
+end
+
+minetest.register_on_newplayer(spawn_player)
+minetest.register_on_respawnplayer(spawn_player)