Add missing mapgen noise parameters

[minetest_perlin_explorer.git] / init.lua

local S = minetest.get_translator("perlin_explorer")
local F = minetest.formspec_escape

-----------------------------
-- Variable initialization --
-----------------------------

local mod_storage = minetest.get_mod_storage()

-- If true, the Perlin test nodes will support color
-- (set to false in case of performance problems)
local COLORIZE_NODES = true

-- If true, will use the grayscale color palette.
-- If false, will use the default colors.
local grayscale_colors = minetest.settings:get_bool("perlin_explorer_grayscale", false)

-- Shows a star on generating new noisechunks
local mapgen_star = minetest.settings:get_bool("perlin_explorer_mapgen_star", true)

-- The number of available test node colors.
-- Higher values lead to worse performance but a coarse color scheme.
-- This value is only used for performance reason, because Minetest
-- has a sharp performance drop when there are many different node colors on screen.
-- Consider removing this one when Minetest's performance problem has been solved.
local color_count = tonumber(minetest.settings:get("perlin_explorer_color_count")) or 64
local color_lookup = {
        [256] = 1, -- full color palette
        [128] = 2,
        [64] = 4,
        [32] = 8,
        [16] = 16,
        [8] = 32,
        [4] = 64,
        [2] = 128,
        [1] = 256,
}
-- This value is used for the calculation of the simplified color.
local color_precision = color_lookup[color_count]
if not color_precision then
        color_precision = 4 -- default: 64 colors
        minetest.log("warning", "[perlin_explorer] Invalid setting value specified for 'perlin_explorer_color_count'! Using the default ...")
end

-- Time to wait in seconds before checking and generating new nodes in autobuild mode.
local AUTOBUILD_UPDATE_TIME = 0.1

-- x/y/z size of "noisechunks" (like chunks in the Minetest mapgen, but specific to this
-- mod) to generate in autobuild mode.
local AUTOBUILD_SIZE = 16
-- Amount of noisechunks to generate around player
local AUTOBUILD_CHUNKDIST = 2


-- Color of the formspec box[] element
local FORMSPEC_BOX_COLOR = "#00000080"
-- Color for the section titles in the formspec
local FORMSPEC_HEADER_COLOR = "#000000FF"
-- Color of the diagram lines of the histogram
local FORMSPEC_HISTOGRAM_LINE_COLOR = "#FFFFFF80"
-- Color of hisogram bars
local FORMSPEC_HISTOGRAM_BAR_COLOR = "#00FF00FF"

-- Number of data buckets to use for the histogram
local HISTOGRAM_BUCKETS = 10

-- Number of values to pick in a statistics run
local STATISTICS_ITERATIONS = 1000000

-- This number is used to pick a reasonable size of the area
-- over which to calculate statistics on. The size (side length
-- of the area/volume, to be precise)
-- is the maximum spread (of the 2 or 3 axes) times this number.
-- This is needed so the randomly picked values in that
-- area are more evenly distributed and lot heavily
-- localized (which would skew the stats).
-- If this is too small, the stats will be too localized, but
-- if this is too large, it will limit the maximum supported
-- noise spread.
local STATISTICS_SPREAD_FACTOR = 69
-- Maximum size of the statistics calculation area (side length of square area /
-- cube volume). Must make sure that Minetest still accepts coordinates
-- in this range.
local STATISTICS_MAX_SIZE = math.floor((2^32-1)/1000)
-- Maximum allowed spread for statistics to still be supported.
-- Used for triggering error message.
local STATISTICS_MAX_SPREAD = math.floor(STATISTICS_MAX_SIZE / STATISTICS_SPREAD_FACTOR)

-- Hardcoded message text
local TEXT_ERROR_BAD_WAVELENGTH = S("Bad noise parameters given. At least one of the resulting wavelengths got below 1, which is not allowed. Decrease the octaves or lacunarity, or increase the spread to reach valid wavelengths. Use the “Analyze” feature to see the wavelengths.")

-- Per-player formspec states (mostly for remembering checkbox states)
local formspec_states = {}

-- List of noise parameters profiles
-- Format of a single profile:
-- * noiseparams: Noise parameters table
-- * name: Name as it appears in list (not set for user profiles)
-- * np_type: Type
--    * "active": Active noise parameters. Not deletable
--    * "mapgen": Noise parameters loaded from Minetest settings. Not deletable
--    * "user": Profiles created by user. Deletable
local np_profiles = {}

-- The default noiseparams are used as the initial noiseparams
-- or as fallback when stuff fails.
local default_noiseparams = {
        offset = 0.0,
        scale = 1.0,
        spread = vector.new(10, 10, 10),
        seed = 0,
        octaves = 2,
        persistence = 0.5,
        lacunarity = 2.0,
        flags = "defaults",
}

-- Get default noise params by setting (if available)
local np_by_setting = minetest.settings:get_np_group("perlin_explorer_default_noiseparams")
if np_by_setting then
        default_noiseparams = np_by_setting
        minetest.log("info", "[perlin_explorer] default noiseparams read from setting")
end

-- Holds the currently used Perlin noise
local current_perlin = {}
-- holds the current PerlinNoise object
current_perlin.noise = nil
current_perlin.noiseparams = table.copy(default_noiseparams)

local noise_settings = dofile(minetest.get_modpath(minetest.get_current_modname()).."/noise_settings_list.lua")

-- Add the special "active" profile
table.insert(np_profiles, {noiseparams=current_perlin.noiseparams, name=S("Active Noise Parameters"), np_type="active"})

-- Add the mapgen setting profiles
for n=1, #noise_settings do
        local np = minetest.get_mapgen_setting_noiseparams(noise_settings[n])
        -- TODO/FIXME: Make sure that ALL noise settings are gettable (not just those of the active mapgen)
        if np then
                table.insert(np_profiles, {noiseparams=np, name=noise_settings[n], np_type="mapgen"})
        end
end

-- Load user profiles from mod storage
minetest.log("info", "[perlin_explorer] Checking for user profiles in mod storage ...")
if mod_storage:contains("profiles") then
        local user_profiles_str = mod_storage:get_string("profiles")
        local user_profiles = minetest.deserialize(user_profiles_str)
        local loaded = 0
        if user_profiles then
                for p=1, #user_profiles do
                        local user_profile = user_profiles[p]
                        if user_profile and type(user_profile) == "table" and user_profile.noiseparams then
                                table.insert(np_profiles, {
                                        np_type = "user",
                                        noiseparams = user_profiles[p].noiseparams,
                                })
                                loaded = loaded + 1
                        else
                                minetest.log("warning", "[perlin_explorer] Malformed user profile in mod storage! Skipping ...")
                        end
                end
        end
        minetest.log("action", "[perlin_explorer] Loaded "..loaded.." user profile(s) from mod storage")
end

-- Updates the user profiles in the mod stroage.
-- Must be called whenever the user profiles change.
local function update_mod_stored_profiles()
        local user_profiles = {}
        for p=1, #np_profiles do
                local profile = np_profiles[p]
                if profile.np_type == "user" then
                        table.insert(user_profiles, {
                                noiseparams = table.copy(profile.noiseparams),
                        })
                end
        end
        local serialized_profiles = minetest.serialize(user_profiles)
        mod_storage:set_string("profiles", serialized_profiles)
        minetest.log("info", "[perlin_explorer] Profiles in mod storage updated")
end

-- Options are settings that dictate how the noise is supposed
-- to be generated.
local current_options = {}
-- Side length of calculated perlin area
current_options.size = 64

-- Noise value that will be represented by the minimum color
current_options.min_color = -1.0
-- Noise value that will be represented by the maximum color
current_options.max_color = 1.0
-- Noise value that is interpreted as the midpoint for node colorization
current_options.mid_color = 0.0

-- Currently selected nodetype for the mapgen (see `nodetypes` table)
current_options.nodetype = 1

-- Currently selected build mode for the mapgen (see below)
-- These modes are available:
-- * Auto (1): same as ALL in 2D mode, same as HIGH_ONLY in 3D mode
-- * All (2): build nodes for all noise values
-- * High only (3): build nodes for high noise values only
-- * Low only (4): build nodes for low noise values only

local BUILDMODE_AUTO = 1
local BUILDMODE_ALL = 2
local BUILDMODE_HIGH_ONLY = 3
local BUILDMODE_LOW_ONLY = 4
local BUILDMODES_COUNT = 4
current_options.buildmode = BUILDMODE_AUTO

-- dimensions of current Perlin noise (2 or 3)
current_options.dimensions = 2
-- If greater than 1, the Perlin noise values are "pixelized". Noise values at
-- coordinates not divisible by sidelen will be set equal to the noise value
-- of the nearest number (counting downwards) that is divisible by sidelen.
-- This is (kind of) analogous to the "sidelen" parameter of mapgen decorations.
current_options.sidelen = 1
-- Place position of current perlin (relevant for single placing)
current_options.pos = nil

-- If enabled, automatically generate nodes around player
current_options.autogen = false

-- Remember which areas have been loaded by the autogen so far
-- Index: Hash of node position, value: true if loaded
local loaded_areas = {}

----------------------
-- Helper functions --
----------------------

-- Reduce the pos coordinates down to the closest numbers divisible by sidelen
local sidelen_pos = function(pos, sidelen)
        local newpos = {x=pos.x, y=pos.y, z=pos.z}
        if sidelen <= 1 then
                return newpos
        end
        newpos.x = newpos.x - newpos.x % sidelen
        newpos.y = newpos.y - newpos.y % sidelen
        newpos.z = newpos.z - newpos.z % sidelen
        return newpos
end

-- A hack to force a formspec to be unique.
-- Appends invisible filler content, changing
-- every time this function is called.
-- This will force the formspec to be unique.
-- Neccessary because Minetest doesn’t update
-- the formspec when the same formspec was
-- sent twice. This is a problem because the
-- player might have edited a text field, causing
-- the formspec to not properly update.
-- Only use this function for one formspec
-- type, otherwise it won’t work.
-- Workaround confirmed working for: Minetest 5.5.0
-- FIXME: Drop this when Minetest no longer does
-- this.
local unique_formspec_spaces = function(player_name, formspec)
        -- Increase the sequence number every time
        -- this thing is used, causing the number
        -- of spaces to change
        local seq = formspec_states[player_name].sequence_number
        seq = (seq + 1) % 4
        local filler = string.rep(" ", seq)
        formspec_states[player_name].sequence_number = seq
        return formspec .. filler
end

-- Takes the 3 noise flags default/eased/absvalue (either true or false)
-- and converts them to a string
local build_flags_string = function(defaults, eased, absvalue)
        local flagst = {}
        if defaults then
                table.insert(flagst, "defaults")
        end
        if eased then
                table.insert(flagst, "eased")
        else
                table.insert(flagst, "noeased")
        end
        if absvalue then
                table.insert(flagst, "absvalue")
        else
                table.insert(flagst, "noabsvalue")
        end
        local flags = table.concat(flagst, ",")
        return flags
end
-- Takes a flags string (in the noiseparams format)
-- and returns a table of the form {
--      defaults = true/false
--      eased = true/false
--      absvalue = true/false
-- }.
local parse_flags_string = function(flags)
        local ftable = string.split(flags, ",")
        local defaults, eased, absvalue = false, false, false
        for f=1, #ftable do
                local s = string.trim(ftable[f])
                if s == "defaults" then
                        defaults = true
                elseif s == "eased" then
                        eased = true
                elseif s == "absvalue" then
                        absvalue = true
                end
        end
        if not defaults and not eased and not absvalue then
                defaults = true
        end
        return { defaults = defaults, eased = eased, absvalue = absvalue }
end

-- Sets the currently active Perlin noise.
-- * noiseparams: NoiseParams table (see Minetest's Lua API documentation)
local set_perlin_noise = function(noiseparams)
        current_perlin.noise = PerlinNoise(noiseparams)
        current_perlin.noiseparams = noiseparams
end

-- Register list of node types for test mapgen
local nodetypes = {
        -- { Entry name for sformspec, high value node, low value node, supports color? }
        { S("Solid Nodes"), "perlin_explorer:node", "perlin_explorer:node_low", true },
        { S("Grid Nodes"), "perlin_explorer:grid", "perlin_explorer:grid_low", true },
        { S("Minibox Nodes"), "perlin_explorer:mini", "perlin_explorer:mini_low", true },
}

-- Analyze the given noiseparams for interesting properties.
-- Returns: <min>, <max>, <waves>, <bad_wavelength>
-- min = minimum possible value
-- max = maximum possible value
-- waves = table with x/y/z indices, each containing a list of effective "wavelengths" for each of the axes
-- bad_wavelength = true if any wavelength is lower than 1
local analyze_noiseparams = function(noiseparams)
        local np = noiseparams

        local flags = parse_flags_string(noiseparams.flags)
        local is_absolute = flags.absvalue == true
        -- Calculate min. and max. possible values
        -- Octaves
        local o_min, o_max = 0, 0
        for o=1, np.octaves do
                local exp = o-1
                o_max = o_max + (1 * np.persistence ^ exp)
                if not is_absolute then
                        o_min = o_min + (- 1 * np.persistence ^ exp)
                        -- Note: If absvalue flag is set, the sum of the octaves
                        -- is always 0, so we don't need to calculate it
                end
        end
        -- Add offset and scale to min/max value (final step)
        local min_value = np.offset + np.scale * o_min
        local max_value = np.offset + np.scale * o_max

        -- Bring the 2 values in the correct order
        -- (min_value might be bigger for negative scale)
        if min_value > max_value then
                min_value, max_value = max_value, min_value
        end

        local bad_wavelength = false
        -- Calculate "wavelengths"
        local axes = { "x", "y", "z" }
        local waves = {}
        for a=1, #axes do
                local w = axes[a]
                waves[w] = {}
                local wave = np.spread[w]
                for o=1, np.octaves do
                        if wave < 1 then
                                bad_wavelength = true
                        end
                        table.insert(waves[w], wave)
                        wave = wave * (1 / np.lacunarity)
                end
        end
        return min_value, max_value, waves, bad_wavelength
end

-- Add stone node to nodetypes, if present
minetest.register_on_mods_loaded(function()
        local stone = minetest.registered_aliases["mapgen_stone"]
        if stone then
                local desc = minetest.registered_nodes[stone].description
                if not desc then
                        desc = stone
                end
                table.insert(nodetypes, { desc, stone, "air", false})
        end
end)

-----------
-- Nodes --
-----------

-- Add a bunch of nodes to generate a map based on a perlin noise.
-- Used for visualization.
-- Each nodes comes in a "high" and "low" variant.
-- high/low means it represents high/low noise values.
local paramtype2, palette
if COLORIZE_NODES then
        paramtype2 = "color"
end
if grayscale_colors then
        palette = "perlin_explorer_node_palette_gray.png"
        palette_low = "perlin_explorer_node_palette_gray_low.png"
else
        palette = "perlin_explorer_node_palette.png"
        palette_low = "perlin_explorer_node_palette_low.png"
end

-- Solid nodes: Visible, walkable, opaque
minetest.register_node("perlin_explorer:node", {
        description = S("Solid Perlin Test Node (High Value)"),
        paramtype = "light",
        -- Intentionally does not cast shadow so that
        -- cave structures are always fullbright when
        -- the sun shines.
        sunlight_propagates = true,
        paramtype2 = paramtype2,
        tiles = {"perlin_explorer_node.png"},
        palette = palette,
        groups = { dig_immediate = 3 },
        -- Force-drop without metadata to avoid spamming the inventory
        drop = "perlin_explorer:node",
})
minetest.register_node("perlin_explorer:node_low", {
        description = S("Solid Perlin Test Node (Low Value)"),
        paramtype = "light",
        sunlight_propagates = true,
        paramtype2 = paramtype2,
        tiles = {"perlin_explorer_node_low.png"},
        palette = palette_low,
        groups = { dig_immediate = 3 },
        -- Force-drop without metadata to avoid spamming the inventory
        drop = "perlin_explorer:node_low",
})

-- Grid nodes: See-through, walkable. Looks like glass.
-- Useful to see "inside" of 3D blobs.
minetest.register_node("perlin_explorer:grid", {
        description = S("Grid Perlin Test Node (High Value)"),
        paramtype = "light",
        drawtype = "allfaces",
        use_texture_alpha = "clip",
        sunlight_propagates = true,
        paramtype2 = paramtype2,
        tiles = {"perlin_explorer_grid.png"},
        palette = "perlin_explorer_node_palette.png",
        palette = palette,
        groups = { dig_immediate = 3 },
        drop = "perlin_explorer:grid",
})
minetest.register_node("perlin_explorer:grid_low", {
        description = S("Grid Perlin Test Node (Low Value)"),
        paramtype = "light",
        drawtype = "allfaces",
        sunlight_propagates = true,
        paramtype2 = paramtype2,
        tiles = {"perlin_explorer_grid_low.png"},
        use_texture_alpha = "clip",
        palette = palette_low,
        groups = { dig_immediate = 3 },
        drop = "perlin_explorer:grid_low",
})

-- Minibox nodes: See-through, non-walkable, climbable.
-- Looks like dot clouds in large numbers.
-- Useful to see and move "inside" of 3D blobs.
minetest.register_node("perlin_explorer:mini", {
        description = S("Minibox Perlin Test Node (High Value)"),
        paramtype = "light",
        drawtype = "nodebox",
        climbable = true,
        walkable = false,
        node_box = {
                type = "fixed",
                fixed = { -2/16, -2/16, -2/16, 2/16, 2/16, 2/16 },
        },
        use_texture_alpha = "clip",
        sunlight_propagates = true,
        paramtype2 = paramtype2,
        tiles = {"perlin_explorer_mini.png"},
        palette = palette,
        groups = { dig_immediate = 3 },
        drop = "perlin_explorer:mini",
})
minetest.register_node("perlin_explorer:mini_low", {
        description = S("Minibox Perlin Test Node (Low Value)"),
        paramtype = "light",
        drawtype = "nodebox",
        climbable = true,
        walkable = false,
        node_box = {
                type = "fixed",
                fixed = { -2/16, -2/16, -2/16, 2/16, 2/16, 2/16 },
        },
        sunlight_propagates = true,
        paramtype2 = paramtype2,
        tiles = {"perlin_explorer_mini_low.png"},
        use_texture_alpha = "clip",
        palette = palette_low,
        groups = { dig_immediate = 3 },
        drop = "perlin_explorer:mini_low",
})

-- Helper function for the getter tool. Gets a noise value at pos
-- and print is in user's chat.
-- * pos: Position to get
-- * user: Player object
-- * precision: Coordinate precision of output (for minetest.pos_to_string)
-- * ptype: One of ...
--          "node": Get value at node position
--          "player": Get value at player position
local print_value = function(pos, user, precision, ptype)
        local val
        local getpos = sidelen_pos(pos, current_options.sidelen)
        if current_options.dimensions == 2 then
                val = current_perlin.noise:get_2d({x=getpos.x, y=getpos.z})
        elseif current_options.dimensions == 3 then
                val = current_perlin.noise:get_3d(getpos)
        else
                error("[perlin_explorer] Unknown/invalid number of Perlin noise dimensions!")
                return
        end
        local msg
        local color_node = minetest.get_color_escape_sequence("#FFD47CFF")
        local color_player = minetest.get_color_escape_sequence("#87FF87FF")
        local color_end = minetest.get_color_escape_sequence("#FFFFFFFF")
        if ptype == "node" then
                msg = S("Value at @1node@2 pos @3: @4", color_node, color_end, minetest.pos_to_string(pos, precision), val)
        elseif ptype == "player" then
                msg = S("Value at @1player@2 pos @3: @4", color_player, color_end, minetest.pos_to_string(pos, precision), val)
        else
                error("[perlin_explorer] Invalid ptype in print_value()!")
        end
        minetest.chat_send_player(user:get_player_name(), msg)
end

-- Get Perlin value of player pos (on_use callback)
local use_getter = function(itemstack, user, pointed_thing)
        if not user then
                return
        end
        local privs = minetest.get_player_privs(user:get_player_name())
        if not privs.server then
                minetest.chat_send_player(user:get_player_name(), S("Insufficient privileges! You need the @1 privilege to use this tool.", "server"))
                return
        end
        if current_perlin.noise then
                local pos = user:get_pos()
                local ctrl = user:get_player_control()
                local precision = 1
                if not ctrl.sneak then
                        pos = vector.round(pos)
                        precision = 0
                end
                print_value(pos, user, precision, "player")
        else
                local msg = S("No active Perlin noise set. Set one first!")
                minetest.chat_send_player(user:get_player_name(), msg)
        end
end

-- Get Perlin value of pointed node (on_place callback)
local place_getter = function(itemstack, user, pointed_thing)
        if not user then
                return
        end
        local privs = minetest.get_player_privs(user:get_player_name())
        if not privs.server then
                minetest.chat_send_player(user:get_player_name(), S("Insufficient privileges! You need the @1 privilege to use this tool.", "server"))
                return
        end
        if current_perlin.noise then
                if pointed_thing.type ~= "node" then
                        -- No-op for non-nodes
                        return
                end
                local pos = pointed_thing.under
                print_value(pos, user, 0, "node")
        else
                local msg = S("No active Perlin noise set. Set one first!")
                minetest.chat_send_player(user:get_player_name(), msg)
        end
end

-- Gets perlin noise value
minetest.register_tool("perlin_explorer:getter", {
        description = S("Perlin Value Getter"),
        _tt_help = S("Place: Display Perlin noise value of the pointed node position").."\n"..
                S("Punch: Display Perlin noise value of player position (+Sneak: precise position)"),
        inventory_image = "perlin_explorer_getter.png",
        wield_image = "perlin_explorer_getter.png",
        groups = { disable_repair = 1 },
        on_use = use_getter,
        on_place = place_getter,
})

--[[ Calculate the Perlin noise value and optionally generate nodes.
* pos: Bottom front left position of where Perlin noise begins
* noise: Perlin noise object to use
* noiseparams: noise parameters table
* options: see at create_perlin function
* stats_mode: if true, will only calculate values for statistics but not place any nodes
Returns: a stats table of the form
{
        min,    -- minimum calculated noise value
        max,    -- maximum calculated noise value
        avg,    -- average calculated noise value
        value_count, -- number of values that were calculated
        histogram, -- histogram data for the stats screen. A list
                -- of "buckets", starting with the lower bounds:
                {
                        [1] = <number of values in 1st bucket>,
                        [2] = <number of values in 2nd bucket>,
                        -- ... etc. ...
                        [HISTOGRAM_BUCKETS] = <number of values in last bucket>,
                }
        histogram_points, -- List of cutoff points for each of the
                        -- data buckets
        start_pos, -- lower corner of the area that the stats were calculated for
        end_pos, -- upper corner of the area that the stats were calculated for
}
Returns nil on error.
]]
local calculate_noise = function(pos, noise, noiseparams, options, stats_mode)
        -- Init
        local stats
        if not noise then
                return
        end
        local time1 = minetest.get_us_time()

        local size_v = {
                x = options.size,
                y = options.size,
                z = options.size,
        }

        local startpos = pos
        local endpos = vector.add(startpos, options.size-1)

        local y_max = endpos.y - startpos.y
        if options.dimensions == 2 then
                -- We don't need 3rd axis in 2D
                y_max = 0
                startpos.y = pos.y
                endpos.y = pos.y
                size_v.z = nil
        end

        local vmanip, emin, emax, vdata, vdata2, varea
        local content_test_node, content_test_node_low, node_needs_color
        if not stats_mode then
                -- Only needed when we want to place nodes
                vmanip = VoxelManip(startpos, endpos)
                emin, emax = vmanip:get_emerged_area()
                vdata = vmanip:get_data()
                vdata2 = vmanip:get_param2_data()
                varea = VoxelArea:new({MinEdge = emin, MaxEdge = emax})

                content_test_node = minetest.get_content_id(nodetypes[options.nodetype][2])
                content_test_node_low = minetest.get_content_id(nodetypes[options.nodetype][3])
                node_needs_color = nodetypes[options.nodetype][4]
        end

        -- Init stats
        stats = {}
        stats.avg = 0
        local sum_of_values = 0
        stats.value_count = 0

        stats.histogram = {}
        local min_possible, max_possible = analyze_noiseparams(noiseparams)
        local cutoff_points = {}
        -- Calculate the cutoff points for the histogram so we know in which data bucket
        -- to put each value into.
        for d=1,HISTOGRAM_BUCKETS do
                cutoff_points[d] = min_possible + ((max_possible-min_possible) / HISTOGRAM_BUCKETS) * d
                stats.histogram[d] = 0
        end

        local perlin_map
        if not stats_mode then
                -- Initialize Perlin map
                -- The noise values will come from this (unless in Stats Mode)
                local perlin_map_object = PerlinNoiseMap(noiseparams, size_v)
                if options.dimensions == 2 then
                        perlin_map = perlin_map_object:get_2d_map({x=startpos.x, y=startpos.z})
                else
                        perlin_map = perlin_map_object:get_3d_map(startpos)
                end
        end

        local x_max, z_max
        if stats_mode then
                x_max = STATISTICS_ITERATIONS - 1
                y_max = 0
                z_max = 0
        else
                x_max = endpos.x - startpos.x
                z_max = endpos.z - startpos.z
        end

        -- Main loop (time-critical!)
        for x=0, x_max do
        for y=0, y_max do
        for z=0, z_max do
                -- Note: This loop has been optimized for speed, so the code
                -- might not look pretty.
                -- Be careful of the performance implications when touching this
                -- loop

                -- Get Perlin value at current pos
                local abspos
                if not stats_mode then
                        abspos = {
                                x = startpos.x + x,
                                y = startpos.y + y,
                                z = startpos.z + z,
                        }
                elseif stats_mode then
                        abspos = {
                                x = math.random(startpos.x, startpos.x+options.size),
                                y = math.random(startpos.y, startpos.y+options.size),
                                z = math.random(startpos.z, startpos.z+options.size),
                        }
                end
                -- Apply sidelen transformation (pixelize)
                local abspos_get = sidelen_pos(abspos, options.sidelen)
                local indexpos = {
                        x = abspos_get.x - startpos.x + 1,
                        y = abspos_get.y - startpos.y + 1,
                        z = abspos_get.z - startpos.z + 1,
                }

                -- Finally get the noise value
                local perlin_value
                if options.dimensions == 2 then
                        if stats_mode or (indexpos.x < 1 or indexpos.z < 1) then
                                -- The pixelization can move indexpos below 1, in this case
                                -- we get the perlin value directly because it is outside
                                -- the precalculated map. Performance impact is hopefully
                                -- not too bad because this will only occur at the low
                                -- edges.
                                -- Ideally, for cleaner code, the precalculated map would
                                -- take this into account as well but this has not
                                -- been done yet.
                                -- In stats mode, we always calculate the noise value directy
                                -- because the values are spread out.
                                perlin_value = noise:get_2d({x=abspos_get.x, y=abspos_get.z})
                        else
                                -- Normal case: Get value from perlin map
                                perlin_value = perlin_map[indexpos.z][indexpos.x]
                        end
                elseif options.dimensions == 3 then
                        if stats_mode or (indexpos.x < 1 or indexpos.y < 1 or indexpos.z < 1) then
                                -- See above
                                perlin_value = noise:get_3d(abspos_get)
                        else
                                -- See above
                                perlin_value = perlin_map[indexpos.z][indexpos.y][indexpos.x]
                        end
                else
                        error("[perlin_explorer] Unknown/invalid number of Perlin noise dimensions!")
                        return
                end

                -- Statistics
                if not stats.min then
                        stats.min = perlin_value
                elseif perlin_value < stats.min then
                        stats.min = perlin_value
                end
                if not stats.max then
                        stats.max = perlin_value
                elseif perlin_value > stats.max then
                        stats.max = perlin_value
                end
                -- Histogram
                for c=1, HISTOGRAM_BUCKETS do
                        if perlin_value < cutoff_points[c] or c >= HISTOGRAM_BUCKETS then
                                stats.histogram[c] = stats.histogram[c] + 1
                                break
                        end
                end
                -- More stats
                sum_of_values = sum_of_values + perlin_value
                stats.value_count = stats.value_count + 1

                -- This section will set the node
                if not stats_mode then
                        -- Calculate color (param2) for node
                        local zeropoint = options.mid_color
                        local min_size = zeropoint - options.min_color
                        local max_size = options.max_color - zeropoint
                        local node_param2 = 0
                        if node_needs_color then
                                if perlin_value >= zeropoint then
                                        node_param2 = ((perlin_value - zeropoint) / max_size) * 255
                                else
                                        node_param2 = ((zeropoint - perlin_value) / min_size) * 255
                                end
                                node_param2 = math.floor(math.abs(node_param2))
                                node_param2 = math.max(0, math.min(255, node_param2))
                                if node_param2 < 255 then
                                        node_param2 = node_param2 - (node_param2 % color_precision)
                                end
                        end

                        -- Get vmanip index
                        local index = varea:indexp(abspos)
                        if not index then
                                return
                        end

                        -- Set node and param2 in vmanip
                        if perlin_value >= zeropoint then
                                if options.buildmode == BUILDMODE_ALL or options.buildmode == BUILDMODE_HIGH_ONLY or options.buildmode == BUILDMODE_AUTO then
                                        vdata[index] = content_test_node
                                        vdata2[index] = node_param2
                                else
                                        vdata[index] = minetest.CONTENT_AIR
                                        vdata2[index] = 0
                                end
                        else
                                if options.buildmode == BUILDMODE_ALL or options.buildmode == BUILDMODE_LOW_ONLY or (options.buildmode == BUILDMODE_AUTO and options.dimensions == 2) then
                                        vdata[index] = content_test_node_low
                                        vdata2[index] = node_param2
                                else
                                        vdata[index] = minetest.CONTENT_AIR
                                        vdata2[index] = 0
                                end
                        end
                end
        end
        end
        end
        -- Final stats
        stats.avg = sum_of_values / stats.value_count
        stats.histogram_points = cutoff_points
        stats.start_pos = vector.new(startpos.x, startpos.y, startpos.z)
        stats.end_pos = vector.add(stats.start_pos, vector.new(options.size, options.size, options.size))

        if not stats_mode then
                -- Write all the changes to map
                vmanip:set_data(vdata)
                vmanip:set_param2_data(vdata2)
                vmanip:write_to_map()
        end

        local time2 = minetest.get_us_time()
        local timediff = time2 - time1
        minetest.log("verbose", "[perlin_explorer] Noisechunk calculated/generated in "..timediff.." µs")

        return stats
end

-- Initiates Perlin noise calculation and optionally node generation, too.
-- * pos: Where the Perlin noise starts
-- * noise: Perlin noise object
-- * noiseparams: noise parameters table
-- * options: table with:
--      * dimensions: number of Perlin noise dimensions (2 or 3)
--      * size: side length of area/volume to calculate)
--      * sidelen: pixelization
-- * stats_mode: if true, will only calculate values for statistics but not place any nodes
local create_perlin = function(pos, noise, noiseparams, options, stats_mode)
        if not noise then
                return false
        end
        local local_options = table.copy(options)
        local cpos = table.copy(pos)
        local mpos = vector.round(cpos)

        local stats = calculate_noise(mpos, noise, noiseparams, local_options, stats_mode)

        if mapgen_star and not stats_mode then
                -- Show a particle in the center of the newly generated area
                local center = vector.new()
                center.x = mpos.x + options.size/2
                if options.dimensions == 2 then
                        center.y = mpos.y + 3
                else
                        center.y = mpos.y + options.size/2
                end
                center.z = mpos.z + options.size/2
                minetest.add_particle({
                        pos = center,
                        expirationtime = 4,
                        size = 16,
                        texture = "perlin_explorer_new_noisechunk.png",
                        glow = minetest.LIGHT_MAX,
                })
        end

        if stats then
                minetest.log("info", "[perlin_explorer] Perlin noise generated at %s! Stats: min. value=%.3f, max. value=%.3f, avg. value=%.3f", minetest.pos_to_string(mpos), stats.min, stats.max, stats.avg)
                return S("Perlin noise generated at @1!", minetest.pos_to_string(mpos)), stats
        else
                minetest.log("error", "[perlin_explorer] Could not get stats!")
                return false
        end
end

-- Seeder tool helper function.
-- * player: Player object
-- * regen: If true, force map section to regenerate (if autogen is off)
local seeder_reseed = function(player, regen)
        local msg
        if regen and (not current_options.autogen and current_options.pos) then
                msg = S("New random seed set, starting to regenerate nodes …")
                minetest.chat_send_player(player:get_player_name(), msg)
                msg = create_perlin(current_options.pos, current_perlin.noise, current_perlin.noiseparams, current_options, false)
                if msg ~= false then
                        minetest.chat_send_player(player:get_player_name(), msg)
                end
        else
                msg = S("New random seed set!")
                minetest.chat_send_player(player:get_player_name(), msg)
        end
end

-- Generates a function for the seeder tool callbacks, for the
-- on_use, on_secondary_use, on_place callbacks of that tool.
-- * reseed : If true, force map section to regenerate (if autogen is off)
local function seeder_use(reseed)
        return function(itemstack, user, pointed_thing)
                if not user then
                        return
                end
                local privs = minetest.get_player_privs(user:get_player_name())
                if not privs.server then
                        minetest.chat_send_player(user:get_player_name(), S("Insufficient privileges! You need the @1 privilege to use this tool.", "server"))
                        return
                end
                if current_perlin.noise then
                        local noiseparams = table.copy(current_perlin.noiseparams)
                        noiseparams.seed = math.random(0, 2^32-1)
                        set_perlin_noise(noiseparams)
                        loaded_areas = {}
                        seeder_reseed(user, reseed)
                else
                        local msg = S("No active Perlin noise set. Set one first!")
                        minetest.chat_send_player(user:get_player_name(), msg)
                end
        end
end

-- Converts a sidelen (=pixelize) value to a valid one
local fix_sidelen = function(sidelen)
        return math.max(1, math.floor(sidelen))
end

-- Fix some errors in the noiseparams
local fix_noiseparams = function(noiseparams)
        noiseparams.octaves = math.floor(math.max(1, noiseparams.octaves))
        noiseparams.lacunarity = math.max(1.0, noiseparams.lacunarity)
        noiseparams.spread.x = math.floor(math.max(1, noiseparams.spread.x))
        noiseparams.spread.y = math.floor(math.max(1, noiseparams.spread.y))
        noiseparams.spread.z = math.floor(math.max(1, noiseparams.spread.z))
        return noiseparams
end

-- Tool to set new random seed of the noiseparams
minetest.register_tool("perlin_explorer:seeder", {
        description = S("Random Perlin seed setter"),
        _tt_help = S("Punch: Set a random seed for the active Perlin noise parameters").."\n"..
                S("Place: Set a random seed and regenerate nodes (if applicable)"),
        inventory_image = "perlin_explorer_seeder.png",
        wield_image = "perlin_explorer_seeder.png",
        groups = { disable_repair = 1 },
        on_use = seeder_use(false),
        on_secondary_use = seeder_use(true),
        on_place = seeder_use(true),
})

-------------------
-- Chat commands --
-------------------
minetest.register_chatcommand("perlin_set_options", {
        privs = { server = true },
        description = S("Set Perlin map generation options"),
        params = S("<dimensions> <pixelize> <midpoint> <low_color> <high_color> [<node_type> <build_mode>]"),
        func = function(name, param)
                local dimensions, sidelen, mid, min, max, nodetype, buildmode = string.match(param, "([23]) ([0-9]+) ([0-9.-]+) ([0-9.-]+) ([0-9.-]+) ([0-9]) ([0-9])")
                if not dimensions then
                        dimensions, sidelen, mid, min, max = string.match(param, "([0-9]+) ([0-9]+) ([0-9.-]+) ([0-9.-]+) ([0-9.-]+)")
                        if not dimensions then
                                return false
                        end
                end
                dimensions = tonumber(dimensions)
                sidelen = tonumber(sidelen)
                min = tonumber(min)
                mid = tonumber(mid)
                max = tonumber(max)
                nodetype = tonumber(nodetype)
                buildmode = tonumber(buildmode)
                if not dimensions or not sidelen or not min or not mid or not max then
                        return false, S("Invalid parameter type! (only numbers are allowed)")
                end
                dimensions = math.floor(dimensions)
                if dimensions ~= 2 and dimensions ~= 3 then
                        return false, S("Invalid dimensions! (must be 2 or 3)")
                end

                -- Update current options
                if nodetype and buildmode then
                        -- Check nodetype and buildmode
                        nodetype = math.floor(nodetype)
                        buildmode = math.floor(buildmode)
                        if not nodetypes[nodetype] then
                                return false, S("Invalid node type! (must be between 1 and @1)", #nodetypes)
                        end
                        if buildmode < 1 or buildmode > BUILDMODES_COUNT then
                                return false, S("Invalid build mode! (must be between 1 and @1)", BUILDMODES_COUNT)
                        end
                        current_options.nodetype = nodetype
                        current_options.buildmode = buildmode
                end
                current_options.dimensions = dimensions
                current_options.sidelen = fix_sidelen(sidelen)
                current_options.min_color = min
                current_options.mid_color = mid
                current_options.max_color = max

                -- Force mapgen to update
                loaded_areas = {}

                return true, S("Perlin map generation options set!")
        end,
})

minetest.register_chatcommand("perlin_set_noise", {
        privs = { server = true },
        description = S("Set active Perlin noise parameters"),
        params = S("<offset> <scale> <seed> <spread_x> <spread_y> <spread_z> <octaves> <persistence> <lacunarity> [<flags>]"),
        func = function(name, param)
                local offset, scale, seed, sx, sy, sz, octaves, persistence, lacunarity, flags = string.match(param, string.rep("([0-9.-]+) ", 9) .. "([a-zA-Z, ]+)")
                if not offset then
                        offset, scale, seed, sx, sy, sz, octaves, persistence, lacunarity = string.match(param, string.rep("([0-9.-]+) ", 8) .. "([0-9.-]+)")
                        if not offset then
                                return false
                        end
                end
                if not flags then
                        flags = ""
                end
                octaves = tonumber(octaves)
                offset = tonumber(offset)
                sx = tonumber(sx)
                sy = tonumber(sy)
                sz = tonumber(sz)
                persistence = tonumber(persistence)
                lacunarity = tonumber(lacunarity)
                seed = tonumber(seed)
                if not octaves or not offset or not sx or not sy or not sz or not persistence or not lacunarity or not seed then
                        return false, S("Invalid parameter type.")
                end
                local noiseparams = {
                        octaves = octaves,
                        offset = offset,
                        scale = scale,
                        spread = { x = sx, y = sy, z = sz },
                        persistence = persistence,
                        lacunarity = lacunarity,
                        seed = seed,
                        flags = flags,
                }
                noiseparams = fix_noiseparams(noiseparams)
                local _, _, _, badwaves = analyze_noiseparams(noiseparams)
                if badwaves then
                        return false, TEXT_ERROR_BAD_WAVELENGTH
                end
                set_perlin_noise(noiseparams)
                loaded_areas = {}
                return true, S("Active Perlin noise parameters set!")
        end,
})

minetest.register_chatcommand("perlin_generate", {
        privs = { server = true },
        description = S("Generate active Perlin noise"),
        params = S("<pos> <size>"),
        func = function(name, param)
                local x, y, z, size = string.match(param, "([0-9.-]+) ([0-9.-]+) ([0-9.-]+) ([0-9]+)")
                if not x then
                        return false
                end
                x = tonumber(x)
                y = tonumber(y)
                z = tonumber(z)
                size = tonumber(size)
                if not x or not y or not z or not size then
                        return false
                end
                if not x or not y or not z or not size then
                        return false, S("Invalid parameter type.")
                end
                local pos = vector.new(x, y, z)

                minetest.chat_send_player(name, S("Creating Perlin noise, please wait …"))
                local opts = table.copy(current_options)
                opts.size = size
                local msg = create_perlin(pos, current_perlin.noise, current_perlin.noiseparams, opts, false)
                if msg == false then
                        return false, S("No active Perlin noise set. Set one first!")
                end
                return true, msg
        end,
})

minetest.register_chatcommand("perlin_toggle_mapgen", {
        privs = { server = true },
        description = S("Toggle the automatic Perlin noise map generator"),
        params = "",
        func = function(name, param)
                if not current_perlin.noise then
                        return false, S("No active Perlin noise set. Set one first!")
                end
                current_options.autogen = not current_options.autogen
                if current_options.autogen then
                        loaded_areas = {}
                end
                minetest.log("action", "[perlin_explorer] Autogen state is now: "..tostring(current_options.autogen))
                local msg
                if current_options.autogen then
                        msg = S("Mapgen enabled!")
                else
                        msg = S("Mapgen disabled!")
                end
                return true, msg
        end,
})

-- Show an error window to player with the given message.
-- Set analyze_button to true to add a button "Analyze now"
-- to open the analyze window.
local show_error_formspec = function(player, message, analyze_button)
        local buttons
        if analyze_button then
                buttons = "button[1.5,2.5;3,0.75;done;"..F(S("Return")).."]"..
                        "button[5.5,2.5;3,0.75;analyze;"..F(S("Analyze now"))
        else
                buttons = "button[3.5,2.5;3,0.75;done;"..F(S("Return")).."]"
        end

        local form = [[
                formspec_version[4]size[10,3.5]
                container[0.25,0.25]
                box[0,0;9.5,2;]]..FORMSPEC_BOX_COLOR..[[]
                box[0,0;9.5,0.4;]]..FORMSPEC_HEADER_COLOR..[[]
                label[0.25,0.2;]]..F(S("Error"))..[[]
                container[0.25,0.5]
                textarea[0,0;9,1.4;;]]..F(message)..[[;]
                container_end[]
                container_end[]
                ]]..buttons
        minetest.show_formspec(player:get_player_name(), "perlin_explorer:error", form)
end

-- Stats loading screen
local show_histogram_loading_formspec = function(player)
        local form = [[
                formspec_version[4]size[11,2]
                container[0.25,0.25]
                box[0,0;10.5,1.5;]]..FORMSPEC_BOX_COLOR..[[]
                box[0,0;10.5,0.4;]]..FORMSPEC_HEADER_COLOR..[[]
                label[0.25,0.2;]]..F(S("Statistical analysis in progress"))..[[]
                container[0.25,0.8]
                label[0,0;]]..F(S("Collecting data, please wait …"))..[[]
                container_end[]
                container_end[]
                ]]
        minetest.show_formspec(player:get_player_name(), "perlin_explorer:histogram_loading", form)
end

-- Stats screen
local show_histogram_formspec = function(player, options, stats)
        local txt = ""
        local maxh = 6.0
        local histogram
        histogram = "vertlabel[0.1,0.1;"..F(S("Relative frequency")).."]"..
                "label[1.1,8.15;"..F(S("Noise values")).."]"..
                "label[0,7.0;"..F(S("Max.")).."\n"..F(S("Min.")).."]"..
                "tooltip[0,6.8;0.7,1;"..F(S("Upper bounds (exclusive) and lower bounds (inclusive) of the noise value data bucketing")).."]"..
                "box[0.75,0;0.025,8.5;"..FORMSPEC_HISTOGRAM_LINE_COLOR.."]"..
                "box[0,6.65;"..HISTOGRAM_BUCKETS..",0.025;"..FORMSPEC_HISTOGRAM_LINE_COLOR.."]"..
                "box[0,7.8;"..HISTOGRAM_BUCKETS..",0.025;"..FORMSPEC_HISTOGRAM_LINE_COLOR.."]"
        local hstart = 1
        -- Special case: If bucket sizes are equal, only show the last bucket
        -- (can happen if scale=0)
        if HISTOGRAM_BUCKETS > 1 and stats.histogram_points[1] == stats.histogram_points[2] then
                hstart = HISTOGRAM_BUCKETS
        end
        local max_value = 0
        for h=hstart, HISTOGRAM_BUCKETS do
                local value = stats.histogram[h]
                if value > max_value then
                        max_value = value
                end
        end
        -- Drawn histogram bars, tooltips and labels
        for h=hstart, HISTOGRAM_BUCKETS do
                local count = stats.histogram[h]
                local ratio = (stats.histogram[h] / stats.value_count)
                local bar_ratio = (stats.histogram[h] / max_value)
                local perc = ratio * 100
                local perc_f = string.format("%.1f", perc)
                local x = h * 0.9
                local bar_height = math.max(maxh * bar_ratio, 0.001)
                local coords = x..","..maxh-bar_height..";0.8,"..bar_height
                local box = ""
                if count > 0 then
                        box = box .. "box["..coords..";"..FORMSPEC_HISTOGRAM_BAR_COLOR.."]"
                        box = box .. "tooltip["..coords..";"..count.."]"
                end
                box = box .. "label["..x..",6.4;"..F(S("@1%", perc_f)).."]"
                box = box .. "tooltip["..x..",6.2;0.9,0.3;"..count.."]"

                local min, max, min_v, max_v
                if h <= 1 then
                        min = ""
                else
                        min = F(string.format("%.1f", stats.histogram_points[h-1]))
                end
                if h >= HISTOGRAM_BUCKETS then
                        max = ""
                else
                        max = F(string.format("%.1f", stats.histogram_points[h]))
                end

                box = box .. "label["..x..",7.0;"..max.."\n"..min.."]"

                local tt
                if h == 1 then
                        tt = F(S("value < @1", stats.histogram_points[h]))
                elseif h == HISTOGRAM_BUCKETS then
                        tt = F(S("@1 <= value", stats.histogram_points[h-1]))
                else
                        tt = F(S("@1 <= value < @2", stats.histogram_points[h-1], stats.histogram_points[h]))
                end
                box = box .. "tooltip["..x..",6.8;0.9,1;"..tt.."]"

                histogram = histogram .. box
        end
        local vmin, vmax
        if options.dimensions == 2 then
                vmin = S("(@1,@2)", stats.start_pos.x, stats.start_pos.z)
                vmax = S("(@1,@2)", stats.end_pos.x, stats.end_pos.z)
        else
                vmin = S("(@1,@2,@3)", stats.start_pos.x, stats.start_pos.y, stats.start_pos.z)
                vmax = S("(@1,@2,@3)", stats.end_pos.x, stats.end_pos.y, stats.end_pos.z)
        end
        local labels = "textarea[0,0;"..HISTOGRAM_BUCKETS..",2;;;"..
                F(S("Values were picked randomly between noise coordinates @1 and @2.", vmin, vmax)).."\n"..
                F(S("Values calculated: @1", stats.value_count)).."\n"..
                F(S("Minimum calculated value: @1", stats.min)).."\n"..
                F(S("Maximum calculated value: @1", stats.max)).."\n"..
                F(S("Average calculated value: @1", stats.avg)).."]\n"

        local form = [[
                formspec_version[4]size[]]..(HISTOGRAM_BUCKETS+1)..[[,12.5]
                container[0.25,0.25]
                box[0,0;]]..(HISTOGRAM_BUCKETS+0.5)..[[,2.5;]]..FORMSPEC_BOX_COLOR..[[]
                box[0,0;]]..(HISTOGRAM_BUCKETS+0.5)..[[,0.4;]]..FORMSPEC_HEADER_COLOR..[[]
                label[0.25,0.2;]]..F(S("Noise Value Statistics"))..[[]
                container[0.25,0.5]
                ]]..labels..[[
                container_end[]
                container[0,2.75]
                box[0,0;]]..(HISTOGRAM_BUCKETS+0.5)..[[,9.25;]]..FORMSPEC_BOX_COLOR..[[]
                box[0,0;]]..(HISTOGRAM_BUCKETS+0.5)..[[,0.4;]]..FORMSPEC_HEADER_COLOR..[[]
                label[0.25,0.2;]]..F(S("Noise Value Histogram"))..[[]
                container[0.25,0.6]
                ]]..histogram..[[
                container_end[]
                container_end[]
                button[7.25,11.35;3,0.5;done;]]..F(S("Done"))..[[]
                container_end[]
                ]]
        minetest.show_formspec(player:get_player_name(), "perlin_explorer:histogram", form)
end

-- Analyzes the given noise params and shows the result in a pretty-printed formspec to player
local analyze_noiseparams_and_show_formspec = function(player, noiseparams)
        local min, max, waves = analyze_noiseparams(noiseparams)
        local print_waves = function(waves_a)
                local stringified_waves = {}
                for w=1, #waves_a do
                        local strwave
                        local is_bad = false
                        if minetest.is_nan(waves_a[w]) or waves_a[w] == math.huge or waves_a[w] == -math.huge then
                                strwave = minetest.colorize("#FF0000FF", waves_a[w])
                        elseif waves_a[w] < 1  then
                                strwave = minetest.colorize("#FF0000FF", "0")
                        else
                                strwave = string.format("%.0f", waves_a[w])
                        end
                        table.insert(stringified_waves, strwave)
                end
                return table.concat(stringified_waves, ", ")
        end
        local form = [[
                formspec_version[4]size[10,5]
                container[0.25,0.25]
                box[0,0;9.5,3.5;]]..FORMSPEC_BOX_COLOR..[[]
                box[0,0;9.5,0.4;]]..FORMSPEC_HEADER_COLOR..[[]
                label[0.25,0.2;]]..F(S("Noise Parameters Analysis"))..[[]

                label[0.25,0.75;]]..F(S("Minimum possible value: @1", min))..[[]
                label[0.25,1.25;]]..F(S("Maximum possible value: @1", max))..[[]

                label[0.25,1.75;]]..F(S("X wavelengths: @1", print_waves(waves.x)))..[[]
                label[0.25,2.25;]]..F(S("Y wavelengths: @1", print_waves(waves.y)))..[[]
                label[0.25,2.75;]]..F(S("Z wavelengths: @1", print_waves(waves.z)))..[[]

                button[3.5,3.75;3,0.75;done;]]..F(S("Done"))..[[]

                container_end[]
        --]]
        minetest.show_formspec(player:get_player_name(), "perlin_explorer:analyze", form)
end

-- Show the formspec of the Perlin Noise Creator tool to player.
-- The main formspec of this mod!
-- * player: Player object
-- * noiseparams: Initialize formspec with these noiseparams (optional)
-- * profile_id: Preselect this profile (by table index of np_profiles)
-- * f_dimensions: Set to force dimensions (optional)
-- * f_sidelen: Set to force sidelen (optional)
local show_noise_formspec = function(player, noiseparams, profile_id, f_dimensions, f_sidelen)
        local player_name = player:get_player_name()
        local np
        if noiseparams then
                np = noiseparams
        else
                np = current_perlin.noiseparams
        end
        if not profile_id then
                profile_id = 1
        end
        local offset = tostring(np.offset or "")
        local scale = tostring(np.scale or "")
        local seed = tostring(np.seed or "")
        local sx, sy, sz = "", "", ""
        if np.spread then
                sx = tostring(np.spread.x or "")
                sy = tostring(np.spread.y or "")
                sz = tostring(np.spread.z or "")
        end
        local octaves = tostring(np.octaves or "")
        local persistence = tostring(np.persistence or "")
        local lacunarity = tostring(np.lacunarity or "")

        local size = tostring(current_options.size or "")
        local buildmode = tostring(current_options.buildmode or 1)

        local sidelen
        if f_sidelen then
                sidelen = tostring(f_sidelen)
        else
                sidelen = tostring(current_options.sidelen or "")
        end
        local dimensions = f_dimensions
        if not dimensions then
                dimensions = current_options.dimensions or 2
        end
        local dimensions_index = dimensions - 1

        local pos_x, pos_y, pos_z = "", "", ""
        if current_options.pos then
                pos_x = tostring(current_options.pos.x or "")
                pos_y = tostring(current_options.pos.y or "")
                pos_z = tostring(current_options.pos.z or "")
        end
        local value_min = tostring(current_options.min_color or "")
        local value_mid = tostring(current_options.mid_color or "")
        local value_max = tostring(current_options.max_color or "")

        local flags = np.flags
        local flags_table = parse_flags_string(flags)
        local flag_defaults = tostring(flags_table.defaults)
        local flag_eased = tostring(flags_table.eased)
        local flag_absvalue = tostring(flags_table.absvalue)
        formspec_states[player_name].default = flags_table.defaults == true
        formspec_states[player_name].absvalue = flags_table.absvalue == true
        formspec_states[player_name].eased = flags_table.eased == true

        local noiseparams_list = {}
        local counter = 1
        for i=1, #np_profiles do
                local npp = np_profiles[i]
                local name = npp.name
                -- Automatic naming for user profiles
                if npp.np_type == "user" then
                        name = S("Profile @1", counter)
                        counter = counter + 1
                end
                table.insert(noiseparams_list, F(name))
        end
        local noiseparams_list_str = table.concat(noiseparams_list, ",")

        local nodetype_index = (current_options.nodetype)

        local nodetypes_list = {}
        for i=1, #nodetypes do
                table.insert(nodetypes_list, F(nodetypes[i][1]))
        end
        local nodetypes_list_str = table.concat(nodetypes_list, ",")

        local delete_btn = ""
        if #np_profiles > 1 then
                delete_btn = "button[7.25,0;2.0,0.5;delete_np_profile;"..F(S("Delete")).."]"
        end
        local autogen_label
        local create_btn = ""
        local xyzsize = ""
        if current_options.autogen then
                autogen_label = S("Disable mapgen")
        else
                autogen_label = S("Enable mapgen")
                create_btn = "button[3.50,0;3,1;create;"..F(S("Apply and create")).."]"..
                        "tooltip[create;"..F(S("Set these noise parameters and noise options as the “active noise” and create nodes at the given X/Y/Z coordinates with the given size")).."]"
                xyzsize = [[
                field[0.25,1.95;1.75,0.75;pos_x;]]..F(S("X"))..[[;]]..pos_x..[[]
                field[2.10,1.95;1.75,0.75;pos_y;]]..F(S("Y"))..[[;]]..pos_y..[[]
                field[3.95,1.95;1.75,0.75;pos_z;]]..F(S("Z"))..[[;]]..pos_z..[[]
                tooltip[pos_x;]]..F(S("Coordinate for “Apply and create”"))..[[]
                tooltip[pos_y;]]..F(S("Coordinate for “Apply and create”"))..[[]
                tooltip[pos_z;]]..F(S("Coordinate for “Apply and create”"))..[[]

                field[5.95,1.95;1.5,0.75;size;]]..F(S("Size"))..[[;]]..size..[[]
                tooltip[size;]]..F(S("Size of area of nodes to generate (as a sidelength), used by “Apply and create”"))..[[]

                field_close_on_enter[pos_x;false]
                field_close_on_enter[pos_y;false]
                field_close_on_enter[pos_z;false]
                field_close_on_enter[size;false]
                ]]
        end
        local form = [[
                formspec_version[4]size[10,12.5]
                container[0.25,0.25]
                box[0,0;9.5,5.5;]]..FORMSPEC_BOX_COLOR..[[]
                box[0,0;9.5,0.4;]]..FORMSPEC_HEADER_COLOR..[[]
                label[0.15,0.2;]]..F(S("Noise parameters"))..[[]
                container[0.0,0.5]
                dropdown[0.25,0;3,0.5;np_profiles;]]..noiseparams_list_str..[[;]]..profile_id..[[;true]
                button[3.25,0;2.0,0.5;add_np_profile;]]..F(S("Add"))..[[]
                button[5.25,0;2.0,0.5;load_np_profile;]]..F(S("Load"))..[[]
                ]]..delete_btn..[[
                container_end[]
                container[0.0,1.5]
                field[0.25,0;2,0.75;offset;]]..F(S("Offset"))..[[;]]..offset..[[]
                field[3.25,0;2,0.75;scale;]]..F(S("Scale"))..[[;]]..scale..[[]
                field[6.25,0;2,0.75;seed;]]..F(S("Seed"))..[[;]]..seed..[[]
                image_button[8.35,0.0;0.75,0.75;perlin_explorer_seeder.png;set_random_seed;]
                field[0.25,1.2;2,0.75;spread_x;]]..F(S("X Spread"))..[[;]]..sx..[[]
                field[3.25,1.2;2,0.75;spread_y;]]..F(S("Y Spread"))..[[;]]..sy..[[]
                field[6.25,1.2;2,0.75;spread_z;]]..F(S("Z Spread"))..[[;]]..sz..[[]
                field[0.25,2.4;2,0.75;octaves;]]..F(S("Octaves"))..[[;]]..octaves..[[]
                field[3.25,2.4;2,0.75;persistence;]]..F(S("Persistence"))..[[;]]..persistence..[[]
                field[6.25,2.4;2,0.75;lacunarity;]]..F(S("Lacunarity"))..[[;]]..lacunarity..[[]
                checkbox[0.25,3.55;defaults;]]..F(S("defaults"))..[[;]]..flag_defaults..[[]
                checkbox[2.25,3.55;eased;]]..F(S("eased"))..[[;]]..flag_eased..[[]
                checkbox[4.25,3.55;absvalue;]]..F(S("absvalue"))..[[;]]..flag_absvalue..[[]
                button[6.25,3.35;2.0,0.5;analyze;]]..F(S("Analyze"))..[[]
                container_end[]

                field_close_on_enter[offset;false]
                field_close_on_enter[scale;false]
                field_close_on_enter[seed;false]
                field_close_on_enter[spread_x;false]
                field_close_on_enter[spread_y;false]
                field_close_on_enter[spread_z;false]
                field_close_on_enter[octaves;false]
                field_close_on_enter[persistence;false]
                field_close_on_enter[lacunarity;false]
                field_close_on_enter[sidelen;false]

                tooltip[set_random_seed;]]..F(S("Random seed"))..[[]
                tooltip[add_np_profile;]]..F(S("Add the current noise parameter as a new profile into the profile list"))..[[]
                tooltip[load_np_profile;]]..F(S("Load the selected profile from the profile list to replace the noise parameters"))..[[]
                tooltip[delete_np_profile;]]..F(S("Delete the selected profile from the profile list (only works for user profiles)"))..[[]
                tooltip[analyze;]]..F(S("Perform some basic mathematical analysis about these noise parameters"))..[[]
                container_end[]


                container[0.25,6.0]
                box[0,0;9.5,1.6;]]..FORMSPEC_BOX_COLOR..[[]
                box[0,0;9.5,0.4;]]..FORMSPEC_HEADER_COLOR..[[]
                label[0.15,0.2;]]..F(S("Noise options"))..[[]
                dropdown[0.25,0.7;1,0.75;dimensions;]]..F(S("2D"))..[[,]]..F(S("3D"))..[[;]]..dimensions_index..[[;true]
                field[2.25,0.7;2,0.75;sidelen;]]..F(S("Pixelization"))..[[;]]..sidelen..[[]
                button[6.25,0.7;2.0,0.6;statistics;]]..F(S("Statistics"))..[[]
                tooltip[statistics;]]..F(S("Calculate a large amount of noise values under the current settings and show a statistical analysis of these values"))..[[]
                tooltip[sidelen;]]..F(S("If higher than 1, Perlin values will be repeated along all axes every x nodes, for a ‘pixelized’ effect."))..[[]
                container_end[]


                container[0.25,7.85]
                box[0,0;9.5,2.9;]]..FORMSPEC_BOX_COLOR..[[]
                box[0,0;9.5,0.4;]]..FORMSPEC_HEADER_COLOR..[[]
                label[0.15,0.2;]]..F(S("Node generation"))..[[]
                field[0.25,0.75;1.75,0.75;value_mid;]]..F(S("Midpoint"))..[[;]]..value_mid..[[]
                field[2.10,0.75;1.75,0.75;value_min;]]..F(S("Low color at"))..[[;]]..value_min..[[]
                field[3.95,0.75;1.75,0.75;value_max;]]..F(S("High color at"))..[[;]]..value_max..[[]
                button[5.95,0.75;1.00,0.75;autocolor;]]..F(S("Auto"))..[[]
                dropdown[7.55,0.75;1.9,0.75;nodetype;]]..nodetypes_list_str..[[;]]..nodetype_index..[[;true]
                tooltip[nodetype;]]..F(S("Node type: Specify the type of node that you want to generate here"))..[[]
                ]]..xyzsize..[[
                dropdown[7.55,1.95;1.9,0.75;buildmode;]]..F(S("Auto"))..","..F(S("All"))..","..F(S("High only"))..","..F(S("Low only"))..[[;]]..buildmode..[[;true]
                tooltip[buildmode;]]..F(S("Build mode: Specify whether to place nodes for high or low noise values, or all values. Auto = “All” in 2D mode or “Low only” in 3D mode"))..[[]
                tooltip[value_mid;]]..F(S("Noise values equal to or higher than the midpoint are treated as high values, otherwise as low values. Used for node colorization."))..[[]
                tooltip[value_min;]]..F(S("The lowest noise value to be represented by the node color gradient."))..[[]
                tooltip[value_max;]]..F(S("The highest noise value to be represented by the node color gradient."))..[[]
                tooltip[autocolor;]]..F(S("Set the midpoint and low and high color values automatically according to the theoretical noise value boundaries."))..[[]
                field_close_on_enter[value_mid;false]
                field_close_on_enter[value_min;false]
                field_close_on_enter[value_max;false]
                container_end[]


                container[0,10.95]
                button[0.25,0;3.15,1;apply;]]..F(S("Apply"))..[[]
                tooltip[apply;]]..F(S("Set these noise parameters and noise options as the “active noise”")).."]"..
                create_btn..[[
                button[6.60,0;3.15,1;toggle_autogen;]]..F(autogen_label)..[[]
                tooltip[toggle_autogen;]]..F(S("Toggle the automatic map generator"))..[[]
                container_end[]
        ]]
        -- Hack to fix Minetest issue (see function comment)
        form = unique_formspec_spaces(player_name, form)
        minetest.show_formspec(player_name, "perlin_explorer:creator", form)
end

-- Formspec handling
minetest.register_on_player_receive_fields(function(player, formname, fields)
        -- Require 'server' priv
        local privs = minetest.get_player_privs(player:get_player_name())
        if not privs.server then
                return
        end

        -- Analysis window
        if formname == "perlin_explorer:analyze" or formname == "perlin_explorer:error" then
                if fields.done then
                        local noiseparams = formspec_states[player:get_player_name()].noiseparams
                        show_noise_formspec(player, noiseparams)
                elseif fields.analyze then
                        local noiseparams = formspec_states[player:get_player_name()].noiseparams
                        analyze_noiseparams_and_show_formspec(player, noiseparams)
                end
                return
        end

        -- Histogram window
        if formname == "perlin_explorer:histogram" then
                if fields.done then
                        local noiseparams = formspec_states[player:get_player_name()].noiseparams
                        local dimensions = formspec_states[player:get_player_name()].dimensions
                        local sidelen = formspec_states[player:get_player_name()].sidelen
                        show_noise_formspec(player, noiseparams, nil, dimensions, sidelen)
                end
                return
        end

        -- Creator window
        if formname ~= "perlin_explorer:creator" then
                return
        end

        -- Handle checkboxes
        local player_name = player:get_player_name()
        local flags_touched = false
        if fields.defaults == "true" then
                formspec_states[player_name].defaults = true
                return
        elseif fields.defaults == "false" then
                formspec_states[player_name].defaults = false
                return
        end
        if fields.eased == "true" then
                formspec_states[player_name].eased = true
                return
        elseif fields.eased == "false" then
                formspec_states[player_name].eased = false
                return
        end
        if fields.absvalue == "true" then
                formspec_states[player_name].absvalue = true
                return
        elseif fields.absvalue == "false" then
                formspec_states[player_name].absvalue = false
                return
        end

        -- Deleting a profile does not require any other field
        if fields.delete_np_profile then
                if #np_profiles <= 1 then
                        return
                end
                local profile_to_delete = tonumber(fields.np_profiles)
                -- Can only delete user profiles
                if np_profiles[profile_to_delete].np_type ~= "user" then
                        return
                end
                table.remove(np_profiles, profile_to_delete)
                update_mod_stored_profiles()
                local new_id = math.max(1, profile_to_delete - 1)
                show_noise_formspec(player, default_noiseparams, new_id)
                return
        end
        -- Handle other fields
        local enter_pressed = fields.key_enter_field ~= nil
        local do_apply = fields.apply ~= nil or fields.toggle_autogen ~= nil
        local do_create = fields.create ~= nil
        if current_options.autogen then
                do_apply = do_apply or enter_pressed
        else
                do_create = do_create or enter_pressed
        end
        local do_analyze = fields.analyze ~= nil
        if (do_create or do_apply or do_analyze or fields.add_np_profile or fields.np_profiles) then
                if fields.offset and fields.scale and fields.seed and fields.spread_x and fields.spread_y and fields.spread_z and fields.octaves and fields.persistence and fields.lacunarity then

                        local offset = tonumber(fields.offset)
                        local scale = tonumber(fields.scale)
                        local seed = tonumber(fields.seed)
                        local sx = tonumber(fields.spread_x)
                        local sy = tonumber(fields.spread_y)
                        local sz = tonumber(fields.spread_z)
                        if not sx or not sy or not sz then
                                return
                        end
                        local spread = vector.new(sx, sy, sz)
                        local octaves = tonumber(fields.octaves)
                        local persistence = tonumber(fields.persistence)
                        local lacunarity = tonumber(fields.lacunarity)
                        local dimensions = tonumber(fields.dimensions)
                        local sidelen = tonumber(fields.sidelen)
                        local px = tonumber(fields.pos_x)
                        local py = tonumber(fields.pos_y)
                        local pz = tonumber(fields.pos_z)
                        local size = tonumber(fields.size)
                        local value_min = tonumber(fields.value_min)
                        local value_mid = tonumber(fields.value_mid)
                        local value_max = tonumber(fields.value_max)
                        local nodetype = tonumber(fields.nodetype)
                        local buildmode = tonumber(fields.buildmode)
                        if (offset and scale and spread and octaves and persistence) then
                                local defaults = formspec_states[player_name].defaults
                                local eased = formspec_states[player_name].eased
                                local absvalue = formspec_states[player_name].absvalue
                                local noiseparams = {
                                        offset = offset,
                                        scale = scale,
                                        seed = seed,
                                        spread = spread,
                                        octaves = octaves,
                                        persistence = persistence,
                                        lacunarity = lacunarity,
                                        flags = build_flags_string(defaults, eased, absvalue),
                                }
                                noiseparams = fix_noiseparams(noiseparams)
                                -- Open analyze window
                                if do_analyze then
                                        formspec_states[player_name].noiseparams = noiseparams
                                        analyze_noiseparams_and_show_formspec(player, noiseparams)
                                        return
                                -- Change NP profile selection
                                elseif fields.load_np_profile and fields.np_profiles then
                                        local profile = tonumber(fields.np_profiles)
                                        local loaded_np
                                        if np_profiles[profile].np_type == "active" then
                                                -- The "active" profile is a special profile
                                                -- that reads from the active noiseparams.
                                                loaded_np = current_perlin.noiseparams
                                        else
                                                -- Normal case: Read noiseparams from profile itself.
                                                loaded_np = np_profiles[profile].noiseparams
                                        end
                                        -- Load new profile
                                        show_noise_formspec(player, loaded_np, profile)
                                        minetest.log("action", "[perlin_explorer] Loaded perlin noise profile "..profile)
                                        return
                                -- Add new profile and save current noiseparams to it
                                elseif fields.add_np_profile then
                                        table.insert(np_profiles, {
                                                np_type = "user",
                                                noiseparams = noiseparams,
                                        })
                                        update_mod_stored_profiles()
                                        local new_profile = #np_profiles
                                        minetest.log("action", "[perlin_explorer] Perlin noise profile "..new_profile.." added!")
                                        show_noise_formspec(player, noiseparams, new_profile)
                                        return
                                elseif fields.set_random_seed then
                                        -- Randomize seed
                                        local profile = tonumber(fields.np_profiles)
                                        noiseparams.seed = math.random(0, 2^32-1)
                                        show_noise_formspec(player, noiseparams, profile)
                                        return
                                elseif fields.autocolor then
                                        -- Set color fields automatically
                                        local min, max = analyze_noiseparams(noiseparams)
                                        current_options.min_color = min
                                        current_options.max_color = max
                                        current_options.mid_color = min + ((max - min) / 2)
                                        local profile = tonumber(fields.np_profiles)
                                        show_noise_formspec(player, noiseparams, profile)
                                        return
                                end

                                if not (dimensions and sidelen and value_min and value_mid and value_max and nodetype and buildmode) then
                                        return
                                end
                                -- Convert dropdown index to actual dimensions number
                                dimensions = dimensions + 1
                                -- Spread is used differently in 2D
                                if dimensions == 2 then
                                        spread.y = spread.z
                                end
                                local _, _, _, badwaves = analyze_noiseparams(noiseparams)
                                if badwaves then
                                        formspec_states[player_name].noiseparams = noiseparams
                                        show_error_formspec(player, TEXT_ERROR_BAD_WAVELENGTH, true)
                                        return
                                end

                                -- Start statistics calculation
                                if fields.statistics then
                                        formspec_states[player_name].noiseparams = noiseparams
                                        formspec_states[player_name].dimensions = dimensions
                                        formspec_states[player_name].sidelen = sidelen
                                        local max_spread = 0
                                        max_spread = math.max(max_spread, noiseparams.spread.x)
                                        max_spread = math.max(max_spread, noiseparams.spread.y)
                                        max_spread = math.max(max_spread, noiseparams.spread.z)
                                        local ssize = max_spread * STATISTICS_SPREAD_FACTOR
                                        -- A very large size is not allowed because the Minetest functions start to fail and would start to distort the statistics.
                                        if ssize > STATISTICS_MAX_SIZE or max_spread > STATISTICS_MAX_SPREAD then
                                                show_error_formspec(player, S("Sorry, but Perlin Explorer doesn’t support calculating statistics if the spread of any axis is larger than @1.", STATISTICS_MAX_SPREAD), false)
                                                return
                                        end
                                        -- Enforce a minimum size as well to at least 1 million values are in the area
                                        if dimensions == 2 and ssize < 1000 then
                                                ssize = 1000
                                        elseif dimensions == 3 and ssize < 100 then
                                                ssize = 100
                                        end
                                        local start = -math.floor(ssize/2)

                                        local pos = vector.new(start, start, start)
                                        local noise = PerlinNoise(noiseparams)
                                        local options = {
                                                dimensions = dimensions,
                                                size = ssize,
                                                sidelen = sidelen,
                                        }
                                        -- Show a loading formspec
                                        show_histogram_loading_formspec(player)
                                        -- This takes long
                                        local _, stats = create_perlin(pos, noise, noiseparams, options, true)
                                        if stats then
                                                -- Update the formspec to show the result
                                                show_histogram_formspec(player, options, stats)
                                        else
                                                minetest.log("error", "[perlin_explorer] Error while creating stats from Perlin noise!")
                                        end
                                        return
                                end


                                set_perlin_noise(noiseparams)
                                minetest.log("action", "[perlin_explorer] Perlin noise set!")
                                current_options.dimensions = dimensions
                                current_options.sidelen = fix_sidelen(sidelen)
                                current_options.min_color = value_min
                                current_options.mid_color = value_mid
                                current_options.max_color = value_max
                                current_options.nodetype = nodetype
                                current_options.buildmode = buildmode
                                if fields.toggle_autogen then
                                        current_options.autogen = not current_options.autogen
                                        if current_options.autogen then
                                                loaded_areas = {}
                                        end
                                        local profile = tonumber(fields.np_profiles)
                                        show_noise_formspec(player, noiseparams, profile)
                                        minetest.log("action", "[perlin_explorer] Autogen state is now: "..tostring(current_options.autogen))
                                elseif do_create then
                                        if not px or not py or not pz or not size then
                                                return
                                        end
                                        if current_options.autogen then
                                                loaded_areas = {}
                                        end
                                        current_options.size = size
                                        local place_pos = vector.new(px, py, pz)
                                        current_options.pos = place_pos
                                        local msg = S("Creating Perlin noise, please wait …")
                                        minetest.chat_send_player(player_name, msg)
                                        msg = create_perlin(place_pos, current_perlin.noise, current_perlin.noiseparams, current_options, false)
                                        if msg then
                                                minetest.chat_send_player(player_name, msg)
                                        elseif msg == false then
                                                minetest.log("error", "[perlin_explorer] Error generating Perlin noise nodes!")
                                        end
                                elseif do_apply and current_options.autogen then
                                        loaded_areas = {}
                                elseif do_apply and not current_options.autogen then
                                        if not px or not py or not pz then
                                                return
                                        end
                                        local place_pos = vector.new(px, py, pz)
                                        current_options.pos = place_pos
                                end
                        end
                end
        end
end)

-- The main tool of this mod. Opens the Perlin noise creation window.
minetest.register_tool("perlin_explorer:creator", {
        description = S("Perlin Noise Creator"),
        _tt_help = S("Punch to open the Perlin noise creation menu"),
        inventory_image = "perlin_explorer_creator.png",
        wield_image = "perlin_explorer_creator.png",
        groups = { disable_repair = 1 },
        on_use = function(itemstack, user, pointed_thing)
                if not user then
                        return
                end
                local privs = minetest.get_player_privs(user:get_player_name())
                if not privs.server then
                        minetest.chat_send_player(user:get_player_name(), S("Insufficient privileges! You need the @1 privilege to use this tool.", "server"))
                        return
                end
                show_noise_formspec(user)
        end,
})

-- Automatic map generation (autogen).
-- The autogen is kind of a mapgen, but it doesn't use Minetest's
-- mapgen, instead it writes directly to map. The benefit is
-- that this will instantly update when the active noiseparams
-- are changed.
-- This will generate so-called noisechunks, which are like
-- Minetest mapchunks, except with respect to this mod only.
local timer = 0
minetest.register_globalstep(function(dtime)
        timer = timer + dtime
        if timer < AUTOBUILD_UPDATE_TIME then
                return
        end
        timer = 0
        if current_perlin.noise and current_options.autogen then
        local players = minetest.get_connected_players()
        -- Generate close to all connected players
        for p=1, #players do
                local player = players[p]
                local player_name = player:get_player_name()
                -- Helper function for building
                local build = function(pos, pos_hash, player_name)
                        if not pos or not pos.x or not pos.y or not pos.z then
                                minetest.log("error", "[perlin_explorer] build(): Invalid pos!")
                                return
                        end
                        if not pos_hash then
                                minetest.log("error", "[perlin_explorer] build(): Invalid pos_hash!")
                                return
                        end
                        if not loaded_areas[pos_hash] then
                                local opts = table.copy(current_options)
                                opts.size = AUTOBUILD_SIZE
                                -- This actually builds the nodes
                                create_perlin(pos, current_perlin.noise, current_perlin.noiseparams, opts, false)
                                -- Built chunks are marked so they don't get generated over and over
                                -- again
                                loaded_areas[pos_hash] = true
                        end
                end

                -- Build list of coordinates to generate nodes in
                local pos = vector.round(player:get_pos())
                pos = sidelen_pos(pos, AUTOBUILD_SIZE)
                local neighbors = { vector.new(0, 0, 0) }
                local c = AUTOBUILD_CHUNKDIST
                local cc = c
                if current_options.dimensions == 2 then
                        cc = 0
                end
                for cx=-c, c do
                for cy=-cc, cc do
                for cz=-c, c do
                        table.insert(neighbors, vector.new(cx, cy, cz))
                end
                end
                end
                local noisechunks = {}
                for n=1, #neighbors do
                        local offset = vector.multiply(neighbors[n], AUTOBUILD_SIZE)
                        local npos = vector.add(pos, offset)
                        -- Check of position is still within the valid map
                        local node = minetest.get_node_or_nil(npos)
                        if node ~= nil then
                                local hash = minetest.hash_node_position(npos)
                                if not loaded_areas[hash] then
                                        table.insert(noisechunks, {npos, hash})
                                end
                        end
                end
                if #noisechunks > 0 then
                        minetest.log("verbose", "[perlin_explorer] Started building "..#noisechunks.." noisechunk(s)")
                end
                -- Build the nodes!
                for c=1, #noisechunks do
                        local npos = noisechunks[c][1]
                        local nhash = noisechunks[c][2]
                        build(npos, nhash, player_name)
                end
                if #noisechunks > 0 then
                        minetest.log("verbose", "[perlin_explorer] Done building "..#noisechunks.." noisechunk(s)")
                end
        end
        end
end)

-- Player variable init and cleanup
minetest.register_on_joinplayer(function(player)
        local name = player:get_player_name()
        local flags = default_noiseparams.flags
        local flags_table = parse_flags_string(flags)
        formspec_states[name] = {
                defaults = flags_table.defaults,
                eased = flags_table.eased,
                absvalue = flags_table.absvalue,
                sidelen = 1,
                dimensions = 2,
                noiseparams = table.copy(default_noiseparams),

                -- This is used by the `unique_formspec_spaces` hack
                sequence_number = 0,
        }
end)
minetest.register_on_leaveplayer(function(player)
        local name = player:get_player_name()
        formspec_states[name] = nil
end)