copy all standard Dreambuilder mods in from the old subgame

(exactly as last supplied there, updates to these mods will follow later)

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+This document describes the Plantlife mod API.
+
+Last revision: 2015-02-16
+
+
+=========
+Functions
+=========
+
+There are three main functions defined by the main "biome_lib" mod:
+
+spawn_on_surfaces()
+register_generate_plant()
+grow_plants()
+
+There are also several internal, helper functions that can be called if so
+desired, but they are not really intended for use by other mods and may change
+at any time.  They are briefly described below these main functions, but see
+init.lua for details.
+
+Most functions in plants lib are declared locally to avoid namespace
+collisions with other mods.  They are accessible via the "biome_lib" method,
+e.g. biome_lib:spawn_on_surfaces() and so forth.
+
+=====
+spawn_on_surfaces(biome)
+spawn_on_surfaces(sdelay, splant, sradius, schance, ssurface, savoid)
+
+This first function is an ABM-based spawner function originally created as
+part of Ironzorg's flowers mod.  It has since been largely extended and
+expanded.  There are two ways to call this function:  You can either pass it 
+several individual string and number parameters to use the legacy interface,
+or you can pass a single biome definition as a table, with all of your options
+spelled out nicely.  This is the preferred method.
+
+When used with the legacy interface, you must specify the parameters exactly
+in order, with the first five being mandatory (even if some are set to nil),
+and the last one being optional:
+
+sdelay:		The value passed to the ABM's interval parameter, in seconds.
+splant:		The node name of the item to spawn (e.g.
+		"flowers:flower_rose").  A plant will of course only be
+		spawned if the node about to be replaced is air.
+sradius:	Don't spawn within this many nodes of the avoid items
+		mentioned below.  If set to nil, this check is skipped.
+schance:	The value passed to the ABM's chance parameter, normally in
+		the 10-100 range (1-in-X chance of operating on a given node)
+ssurface:	String with the name of the node on which to spawn the plant
+		in question, such as "default:sand" or
+		"default:dirt_with_grass".  It is not recommended to put air,
+		stone, or plain dirt here if you can use some other node, as
+		doing so will cause the engine to process potentially large
+		numbers of such nodes when deciding when to execute the ABM
+		and where it should operate.
+savoid:		Table with a list of groups and/or node names to avoid when
+		spawning the plant, such as {"group:flowers", "default:tree"}.
+
+When passed a table as the argument, and thus using the modern calling method,
+you must pass a number of arguments in the form of an ordinary keyed-value
+table.  Below is a list of everything supported by this function:
+
+biome = {
+	spawn_plants = something, -- [*] String or table; see below.
+	spawn_delay = number,	-- same as sdelay, above.
+	spawn_chance = number,	-- same as schance, above.
+	spawn_surfaces = {table}, -- List of node names on which the plants
+				-- should be spawned.  As with the single-node "ssurface"
+				-- option in the legacy API, you should not put stone, air,
+				-- etc. here.
+
+	---- From here down are a number of optional parameters.  You will
+	---- most likely want to use at least some of these to limit how and
+	---- where your objects are spawned.
+
+	avoid_nodes = {table},	-- same meaning as savoid, above
+	avoid_radius = num,	-- same as sradius
+	seed_diff = num,	-- The Perlin seed difference value passed to the
+						-- minetest.get_perlin() function.  Used along with
+						-- the global Perlin controls below to create the
+						-- "biome" in which the plants will spawn.  Defaults
+						-- to 0 if not provided.
+	light_min = num,	-- Minimum amount of light necessary to make a plant
+						-- spawn.  Defaults to 0.
+	light_max = num,	-- Maximum amount of light needed to spawn.  Defaults
+						-- to the engine's MAX_LIGHT value of 14.
+	neighbors = {table}, -- List of neighboring nodes that need to be
+						-- immediately next to the node the plant is about to
+						-- spawn on. Can also be a string with a single node
+						-- name.  It is both passed to the ABM as the
+						-- "neighbors" parameter, and is used to manually
+						-- check the adjacent nodes.  It only takes one of
+						-- these for the spawn routine to mark the target as
+						-- spawnable.  Defaults to nil (ignored).
+	ncount = num,		-- There must be at least this many of the above
+						-- neighbors in the eight spaces immediately
+						-- surrounding the node the plant is about to spawn on
+						-- for it to happen.  If not provided, this check is
+						-- disabled.
+	facedir = num,		-- The value passed to the param2 variable when adding
+						-- the node to the map.  Defaults to 0.  Be sure that
+						-- the value you use here (and the range thereof) is
+						-- appropriate for the type of node you're spawning.
+	random_facedir = {table}, -- If set, the table should contain two values.
+						-- If they're both provided, the spawned plant will be
+						-- given a random facedir value in the range specified
+						-- by these two numbers.  Overrides the facedir
+						-- parameter above, if it exists.  Use {0,3} if you
+						-- want the full range for wallmounted nodes, or {2,5}
+						-- for most everything else, or any other pair of
+						-- numbers appropriate for the node you want to spawn.
+	depth_max = num,	-- If the object spawns on top of a water source, the
+						-- water must be at most this deep.  Defaults to 1.
+	min_elevation = num, -- Surface must be at this altitude or higher to
+						-- spawn at all.  Defaults to -31000...
+	max_elevation = num, -- ...but must be no higher than this altitude.
+						-- Defaults to +31000.
+	near_nodes = {table}, -- List of nodes that must be somewhere in the
+						-- vicinity in order for the plant to spawn. Can also
+						-- be a string with a single node name.  If not
+						-- provided, this check is disabled.
+	near_nodes_size = num,	-- How large of an area to check for the above
+						-- node.  Specifically, this checks a flat, horizontal
+						-- area centered on the node to be spawned on.
+						-- Defaults to 0, but is ignored if the above
+						-- near_nodes value is not set.
+	near_nodes_vertical = num, -- Used with the size value above, this extends
+						-- the vertical range of the near nodes search.
+						-- Basically, this turns the flat region described
+						-- above into a cuboid region.  The area to be checked
+						-- will extend this high and this low above/below the
+						-- target node, centered thereon.  Defaults to 1 (only
+						-- check the layer above, the layer at, and the layer
+						-- below the target node), but is ignored if
+						-- near_nodes is not set.
+	near_nodes_count = num,	-- How many of the above nodes must be within that
+						-- radius.  Defaults to 1 but is ignored if near_nodes
+						-- isn't set.  Bear in mind that the total area to be
+						-- checked is equal to:
+						-- (near_nodes_size^2)*near_nodes_vertical*2 
+						-- For example, if size is 10 and vertical is 4, then
+						-- the area is (10^2)*8 = 800 nodes in size, so you'll
+						-- want to make sure you specify a value appropriate
+						-- for the size of the area being tested.
+	air_size = num,		-- How large of an area to check for air above and
+						-- around the target.  If omitted, only the space
+						-- above the target is checked.  This does not check
+						-- for air at the sides or below the target.
+	air_count = num,	-- How many of the surrounding nodes need to be air
+						-- for the above check to return true. If omitted,
+						-- only the space above the target is checked.
+	plantlife_limit = num, -- The value compared against the generic "plants
+						-- can grow here" Perlin noise layer. Smaller numbers
+						-- result in more abundant plants.  Range of -1 to +1,
+						-- with values in the range of about 0 to 0.5 being
+						-- most useful.  Defaults to 0.1.
+	temp_min = num,		-- Minimum temperature needed for the desired object
+						-- to spawn.  This is a 2d Perlin value, which has an
+						-- inverted range of +1 to -1.  Larger values
+						-- represent *colder* temperatures, so this value is
+						-- actually the upper end of the desired Perlin range.
+						-- See the temperature map section at the bottom of
+						-- this document for details on how these values work.
+						-- Defaults to +1 (unlimited coldness).
+	temp_max = num,		-- Maximum temperature/lower end of the Perlin range.
+						-- Defaults to -1 (unlimited heat).
+	humidity_min = num,	-- Minimum humidity for the plant to spawn in. Like
+						-- the temperature map, this is a Perlin value where
+						-- lower numbers mean more humidity in the area.
+						-- Defaults to +1 (0% humidity).
+	humidity_max = num,	-- Maximum humidity for the plant to spawn at.
+						-- Defaults to -1 (100% humidity).
+	verticals_list = {table}, -- List of nodes that should be considered to be
+						-- natural walls.
+	alt_wallnode = "string", -- If specified, this node will be substituted in
+						-- place of the plant(s) defined by spawn_plants
+						-- above, if the spawn target has one or more adjacent
+						-- walls.  In such a case, the two above facedir
+						-- parameters will be ignored.
+	spawn_on_side = bool, -- Set this to true to immediately spawn the node on
+						-- one side of the target node rather than the top.
+						-- The code will search for an airspace to the side of
+						-- the target, then spawn the plant at the first one
+						-- found.  The above facedir and random_facedir
+						-- parameters are ignored in this case.  If the above
+						-- parameters for selecting generic wall nodes are
+						-- provided, this option is ignored.  Important note:
+						-- the facedir values assigned by this option only
+						-- make sense with wallmounted nodes (nodes which
+						-- don't use facedir won't be affected).
+	choose_random_wall = bool, -- if set to true, and searching for walls is
+						-- being done, just pick any random wall if there is
+						-- one, rather than returning the first one.
+	spawn_on_bottom = bool,	-- If set to true, spawn the object below the
+						-- target node instead of above it.  The above
+						-- spawn_on_side variable takes precedence over this
+						-- one if both happen to be true. When using this
+						-- option with the random facedir function above, the
+						-- values given to the facedir parameter are for
+						-- regular nodes, not wallmounted.
+	spawn_replace_node = bool, -- If set to true, the target node itself is
+						-- replaced by the spawned object.  Overrides the
+						-- spawn_on_bottom and spawn_on_side settings.
+}
+
+[*] spawn_plants must be either a table or a string.  If it's a table, the
+values therein are treated as a list of nodenames to pick from randomly on 
+each application of the ABM code. The more nodes you can pack into this
+parameter to avoid making too many calls to this function, the lower the CPU
+load will likely be.
+
+You can also specify a string containing the name of a function to execute.
+In this case, the function will be passed a single position parameter
+indicating where the function should place the desired object, and the checks
+for spawning on top vs. sides vs. bottom vs. replacing the target node will be
+skipped.
+
+By default, if a biome node, size, and count are not defined, the biome
+checking is disabled.  Same holds true for the nneighbors bit above that.
+
+
+=====
+biome_lib:register_generate_plant(biome, nodes_or_function_or_treedef)
+
+To register an object to be spawned at mapgen time rather than via an ABM,
+call this function with two parameters:  a table with your object's biome
+information, and a string, function, or table describing what to do if the
+engine finds a suitable surface node (see below).
+
+The biome table contains quite a number of options, though there are fewer 
+here than are available in the ABM-based spawner, as some stuff doesn't make
+sense at map-generation time.
+
+biome = {
+	surface = something, -- What node(s).  May be a string such as
+						-- "default:dirt_with_grass" or a table with
+						-- multiple such entries.
+
+	---- Everything else is optional, but you'll definitely want to use
+	---- some of these other fields to limit where and under what
+	---- conditions the objects are spawned.
+	
+	below_nodes = {table}, -- List of nodes that must be below the target
+						-- node.  Useful in snow biomes to keep objects from
+						-- spawning in snow that's on the wrong surface for
+						-- that object.
+	avoid_nodes = {table}, -- List of nodes to avoid when spawning. Groups are
+						-- not supported here.
+	avoid_radius = num,	-- How much distance to leave between the object to be
+						-- added and the objects to be avoided.  If this or
+						-- the avoid_nodes value is nil/omitted, this check is
+						-- skipped.  Avoid using excessively large radii.
+	rarity = num,		-- How rare should this object be in its biome? Larger
+						-- values make objects more rare, via:
+						-- math.random(1,100) > this
+	max_count = num,	-- The absolute maximum number of your object that
+						-- should be allowed to spawn in a 5x5x5 mapblock area
+						-- (80x80x80 nodes).  Defaults to 5, but be sure you
+						-- set this to some reasonable value depending on your
+						-- object and its size if 5 is insufficient.
+	seed_diff = num,	-- Perlin seed-diff value.  Defaults to 0, which
+						-- causes the function to inherit the global value of
+						-- 329.
+	neighbors = {table}, -- What ground nodes must be right next to and at the
+						-- same elevation as the node to be spawned on.
+	ncount = num,		-- At least this many of the above nodes must be next
+						-- to the node to spawn on.  Any value greater than 8
+						-- will probably cause the code to never spawn
+						-- anything.  Defaults to 0.
+	depth = num,		-- How deep/thick of a layer the spawned-on node must
+						-- be.  Typically used for water.
+	min_elevation = num, -- Minimum elevation in meters/nodes.  Defaults to
+						-- -31000 (unlimited).
+	max_elevation = num, -- Max elevation.  Defaults to +31000 (unlimited).
+	near_nodes = {table}, -- what nodes must be in the general vicinity of the
+						-- object being spawned.
+	near_nodes_size = num, -- how wide of a search area to look for the nodes
+						-- in that list.
+	near_nodes_vertical = num, -- How high/low of an area to search from the
+						-- target node.
+	near_nodes_count = num,	-- at least this many of those nodes must be in
+						-- the area.
+	plantlife_limit = num, -- The value compared against the generic "plants
+						-- can grow here" Perlin noise layer.  Smaller numbers
+						-- result in more abundant plants.  Range of -1 to +1,
+						-- with values in the range of about 0 to 0.5 being
+						-- most useful.  Defaults to 0.1.
+	temp_min = num,		-- Coldest allowable temperature for a plant to spawn
+						-- (that is, the largest Perlin value).
+	temp_max = num,		-- warmest allowable temperature to spawn a plant
+						-- (lowest Perlin value).
+	verticals_list = {table}, -- Same as with the spawn_on_surfaces function.
+	check_air = bool,	-- Flag to tell the mapgen code to check for air above
+						-- the spawn target.  Defaults to true if not
+						-- explicitly set to false.  Set this to false VERY
+						-- SPARINGLY, as it will slow the map generator down.
+	delete_above = bool, -- Flag to tell the mapgen code to delete the two
+						-- nodes directly above the spawn target just before
+						-- adding the plant or tree.  Useful when generating
+						-- in snow biomes.  Defaults to false.
+	delete_above_surround = bool, -- Flag to tell the mapgen code to also
+						-- delete the five nodes surrounding the above space,
+						-- and the five nodes above those, resulting in a two-
+						-- node-deep cross-shaped empty region above/around
+						-- the spawn target.  Useful when adding trees to snow
+						-- biomes.  Defaults to false.
+	spawn_replace_node = bool, -- same as with the ABM spawner.
+	random_facedir = {table}, -- same as with the ABM spawner.
+}
+
+Regarding nodes_or_function_or_treedef, this must either be a string naming
+a node to spawn, a table with a list of nodes to choose from, a table with an
+L-Systems tree definition, or a function.
+
+If you specified a string, the code will attempt to determine whether that
+string specifies a valid node name.  If it does, that node will be placed on
+top of the target position directly (unless one of the other mapgen options
+directs the code to do otherwise).
+
+If you specified a table and there is no "axiom" field, the code assumes that
+it is a list of nodes.  Simply name one node per entry in the list, e.g.
+{"default:junglegrass", "default:dry_shrub"} and so on, for as many nodes as
+you want to list.  A random node from the list will be chosen each time the
+code goes to place a node.
+
+If you specified a table, and there *is* an "axiom" field, the code assumes
+that this table contains an L-Systems tree definition, which will be passed
+directly to the engine's spawn_tree() function along with the position on
+which to spawn the tree.
+
+You can also supply a function to be directly executed, which is given the
+current node position (the usual "pos" table format) as its sole argument.  It
+will be called in the form:
+
+	somefunction(pos)
+
+
+=====
+biome_lib:grow_plants(options)
+
+The third function, grow_plants() is used to turn the spawned nodes above
+into something else over time.  This function has no return value, and accepts
+a biome definition table as the only parameter.  These are defined like so:
+
+options = {
+	grow_plant = "string", -- Name of the node to be grown into something
+						-- else.  This value is passed to the ABM as the
+						-- "nodenames" parameter, so it is the plants
+						-- themselves that are the ABM trigger, rather than
+						-- the ground they spawned on.  A plant will only grow
+						-- if the node above it is air.  Can also be a table,
+						-- but note that all nodes referenced therein will be
+						-- grown into the same object.
+	grow_delay = num,	-- Passed as the ABM "interval" parameter, as with
+						-- spawning.
+	grow_chance = num,	-- Passed as the ABM "chance" parameter.
+	grow_result = "string",	-- Name of the node into which the grow_plant
+						-- node(s) should transform when the ABM executes.
+
+	---- Everything from here down is optional.
+
+	dry_early_node = "string", -- This value is ignored except for jungle
+						-- grass (a corner case needed by that mod), where it
+						-- indicates which node the grass must be on in order
+						-- for it to turn from the short size to
+						-- "default:dry_shrub" instead of the medium size.
+	grow_nodes = {table}, -- One of these nodes must be under the plant in
+						-- order for it to grow at all.  Normally this should
+						-- be the same as the list of surfaces passed to the
+						-- spawning ABM as the "nodenames" parameter.  This is
+						-- so that the plant can be manually placed on
+						-- something like a flower pot or something without it
+						-- necessarily growing and perhaps dieing.  Defaults
+						-- to "default:dirt_with_grass".
+	facedir = num,		-- Same as with spawning a plant.
+	need_wall = bool,	-- Set this to true if you the plant needs to grow
+						-- against a wall.  Defaults to false.
+	verticals_list = {table}, -- same as with spawning a plant.
+	choose_random_wall = bool, -- same as with spawning a plant.
+	grow_vertically = bool,	-- Set this to true if the plant needs to grow
+						-- vertically, as in climbing poison ivy. Defaults to
+						-- false.
+	height_limit = num,	-- Set this to limit how tall the desired node can
+						-- grow.  The mod will search straight down from the
+						-- position being spawned at to find a ground node,
+						-- set via the field below. Defaults to 5 nodes.
+	ground_nodes = {table},	-- What nodes should be treated as "the ground"
+						-- below a vertically-growing plant. Usually this
+						-- should be the same as the grow_nodes table, but
+						-- might also include, for example, water or some
+						-- other surrounding material.  Defaults to
+						-- "default:dirt_with_grass".
+	grow_function = something, -- [*] see below.
+	seed_diff = num,	-- [*] see below.
+}
+
+[*] grow_function can take one of three possible settings:  it can be nil (or
+    not provided), a string, or a table.
+
+If it is not provided or it's set to nil, all of the regular growing code is
+executed normally, the value of seed_diff, if any, is ignored, and the node to
+be placed is assumed to be specified in the grow_result variable.
+
+If this value is set to a simple string, this is treated as the name of the
+function to use to grow the plant.  In this case, all of the usual growing
+code is executeed, but then instead of a plant being simply added to the
+world, grow_result is ignored and the named function is executed and passed a
+few parmeters in the following general form: 
+
+	somefunction(pos, perlin1, perlin2)
+
+These values represent the current position (the usual table), the Perlin
+noise value for that spot in the generic "plants can grow here" map for the
+seed_diff value above, the Perlin value for that same spot from the
+temperature map, and the detected neighboring wall face, if there was one (or
+nil if not).  If seed_diff is not provided, it defaults to 0.
+
+If this variable is instead set to a table, it is treated an an L-Systems tree
+definition.  All of the growing code is executed in the usual manner, then the
+tree described by that definition is spawned at the current position instead,
+and grow_result is ignored.
+
+
+=====
+find_adjacent_wall(pos, verticals, randomflag)
+
+Of the few helper functions, this one expects a position parameter and a table
+with the list of nodes that should be considered as walls.  The code will
+search around the given position for a neighboring wall, returning the first
+one it finds as a facedir value, or nil if there are no adjacent walls.
+
+If randomflag is set to true, the function will just return the facedir of any
+random wall it finds adjacent to the target position.  Defaults to false if 
+not specified.
+
+=====
+is_node_loaded(pos)
+
+This acts as a wrapper for the minetest.get_node_or_nil(node_pos)
+function and accepts a single position parameter.  Returns true if the node in
+question is already loaded, or false if not.
+
+
+=====
+dbg(string)
+
+This is a simple debug output function which takes one string parameter.  It
+just checks if DEBUG is true and outputs the phrase "[Plantlife] " followed by
+the supplied string, via the print() function, if so.
+
+=====
+biome_lib:generate_tree(pos, treemodel)
+biome_lib:grow_tree(pos, treemodel)
+
+In the case of the growing code and the mapgen-based tree generator code, 
+generating a tree is done via the above two calls, which in turn immediately
+call the usual spawn_tree() functions.  This rerouting exists as a way for
+other mods to hook into biome_lib's tree-growing functions in general,
+perhaps to execute something extra whenever a tree is spawned.
+
+biome_lib:generate_tree(pos, treemodel) is called any time a tree is spawned
+at map generation time.  'pos' is the position of the block on which the tree
+is to be placed.  'treemodel' is the standard L-Systems tree definition table
+expected by the spawn_tree() function.  Refer to the 'trunk' field in that
+table to derive the name of the tree being spawned.
+
+biome_lib:grow_tree(pos, treemodel) does the same sort of thing whenever a 
+tree is spawned within the abm-based growing code, for example when growing a
+sapling into a tree.
+
+
+=====
+There are other, internal helper functions that are not meant for use by other
+mods.  Don't rely on them, as they are subject to change without notice.
+
+
+===============
+Global Settings
+===============
+
+Set this to true if you want the mod to spam your console with debug info :-)
+
+	plantlife_debug = false
+
+
+======================
+Fertile Ground Mapping
+======================
+
+The mod uses Perlin noise to create "biomes" of the various plants, via the
+minetest.get_perlin() function.  At present, there are three layers of
+Perlin noise used.
+
+The first one is for a "fertile ground" layer, which I tend to refer to as the
+generic "stuff can potentially grow here" layer.  Its values are hard-coded:
+
+	biome_lib.plantlife_seed_diff = 329
+	perlin_octaves = 3
+	perlin_persistence = 0.6
+	perlin_scale = 100
+
+For more information on how Perlin noise is generated, you will need to search
+the web, as these default values were from that which is used by minetest_game
+to spawn jungle grass at mapgen time, and I'm still learning how Perlin noise
+works.  ;-)
+
+
+===================
+Temperature Mapping
+===================
+
+The second Perlin layer is a temperature map, with values taken from
+SPlizard's Snow Biomes mod so that the two will be compatible, since that mod
+appears to be the standard now.  Those values are:
+
+	temperature_seeddiff = 112
+	temperature_octaves = 3
+	temperature_persistence = 0.5
+	temperature_scale = 150
+
+The way Perlin values are used by this mod, in keeping with the snow mod's 
+apparent methods, larger values returned by the Perlin function represent
+*colder* temperatures.  In this mod, the following table gives a rough
+approximation of how temperature maps to these values, normalized to
+0.53 = 0 °C and +1.0 = -25 °C.
+
+Perlin		Approx. Temperature
+-1.0		 81 °C	( 178 °F)
+-0.75		 68 °C	( 155 °F)
+-0.56		 58 °C	( 136 °F)
+-0.5		 55 °C	( 131 °F)
+-0.25		 41 °C	( 107 °F)
+-0.18		 38 °C	( 100 °F)
+ 0		 28 °C	(  83 °F)
+ 0.13		 21 °C	(  70 °F)
+ 0.25		 15 °C	(  59 °F)
+ 0.5		  2 °C	(  35 °F)
+ 0.53		  0 °C	(  32 °F)
+ 0.75		-12 °C	(  11 °F)
+ 0.86		-18 °C	(   0 °F)
+ 1.0		-25 °C	(- 13 °F)
+
+Included in this table are even 0.25 steps in Perlin values along with some
+common temperatures on both the Centigrade and Fahrenheit scales.  Note that
+unless you're trying to model the Moon or perhaps Mercury in your mods/maps, 
+you probably won't need to bother with Perlin values of less than -0.56 or so.
+
+
+================
+Humidity Mapping
+================
+
+Last but not least is a moisture/humidity map.  Like the temperature map
+above, Perlin values can be tested to determine the approximate humidity of
+the *air* in the area.  This humidity map is basically the perlin layer used
+for deserts.
+
+A value of +1.0 is very moist (basically a thick fog, if it could be seen), a
+value of roughly +0.25 represents the edge of a desert as usually seen in the
+game, and a value of -1.0 is as dry as a bone.
+
+This does not check for nearby water, just general air humidity, and that
+being the case, nearby ground does not affect the reported humidity of a
+region (because this isn't yet possible to calculate yet).  Use the near_nodes
+and avoid_nodes parameters and their related options to check for water and
+such.
+
+The Perlin values use for this layer are:
+
+	humidity_seeddiff = 9130
+	humidity_octaves = 3
+	humidity_persistence = 0.5
+	humidity_scale = 250
+
+And this particular one is mapped slightly differently from the others:
+
+	noise3 = perlin3:get2d({x=p_top.x+150, y=p_top.z+50})
+
+(Note the +150 and +50 offsets)
+