Fix default_biome air node bug

.gitignore

@@ -0,0 +1 @@
+.vscode

API.md

@@ -10,9 +10,9 @@ Underground caves have varying shapes, and the variable
 
 For shapes, the following functions are available:
 
-- `noordstar_caves.register_shape(shape def)` Define a new cave shape
+- `ns_cavegen.register_shape(shape def)` Define a new cave shape
-- `noordstar_caves.unregister_shape(name)` Remove a defined cave shape
+- `ns_cavegen.unregister_shape(name)` Remove a defined cave shape
-- `noordstar_caves.clear_registered_shapes()` Remove all known cave shapes
+- `ns_cavegen.clear_registered_shapes()` Remove all known cave shapes
 
 Generally, it is recommended to keep the number of cave shapes below 100.
 A good number of shapes is 10 for diversity but performance.
@@ -21,7 +21,7 @@ The shapes are defined as follows:
 
 ```lua
 {
-    name = "noordstar_caves:bubbles",
+    name = "ns_cavegen:bubbles",
     -- Unique name identifying the shape
     -- Namespacing is not required but recommended
     
@@ -48,16 +48,6 @@ The shapes are defined as follows:
     --                       |                    |                   |
     --            massive caves only       smaller caves         always cave
 
-    func = function(pos, n)
-        return 2 * n
-    end,
-    -- Function to edit the NoiseParams based on some operation.
-    -- Keep in mind that this function will be run many, many times, so it is
-    -- best to keep this function as trivial as possible.
-    -- The function receives a node's position `pos` and the noise value `n`,
-    -- and it is expected to return an updated noise value.
-    -- If absent, the noise value is used as-is.
-
     y_min = -31000,
     y_max = 31000,
     -- Lower and upper limits for cave shapes.
@@ -105,15 +95,15 @@ caves. The cave biomes are independent of the cave shapes.
 
 For shapes, the following functions are available:
 
-- `noordstar_caves.register_biome(biome def)` Define a new cave biome
+- `ns_cavegen.register_biome(biome def)` Define a new cave biome
-- `noordstar_caves.unregister_biome(name)` Remove a defined cave biome
+- `ns_cavegen.unregister_biome(name)` Remove a defined cave biome
-- `noordstar_caves.clear_registered_biomes()` Remove all known cave biomes
+- `ns_cavegen.clear_registered_biomes()` Remove all known cave biomes
 
 The biomes are defined as follows:
 
 ```lua
 {
-    name = "noordstar_caves:tundra",
+    name = "ns_cavegen:tundra",
     -- Unique name identifying the biome
     -- Namespacing is not required but recommended
 
@@ -165,8 +155,8 @@ structures to cave biomes.
 
 For decorations, the following functions are defined:
 
-- `noordstar_caves.register_decoration(decoration def)` Define a new cave decoration
+- `ns_cavegen.register_decoration(decoration def)` Define a new cave decoration
-- `noordstar_caves.clear_registered_decorations()` Remove all known cave decorations
+- `ns_cavegen.clear_registered_decorations()` Remove all known cave decorations
 
 The decorations are defined as follows:
 
@@ -181,7 +171,7 @@ The decorations are defined as follows:
     fill_ratio = 0.02,
     -- Percentage of surface nodes on which this decoration will spawn
 
-    biomes = { "noordstar_caves:tundra", "foo:desert" },
+    biomes = { "ns_cavegen:tundra", "foo:desert" },
     -- List of (cave!) biomes that this decoration will spawn in. Occurs in all
     -- biomes if this is omitted.
 
@@ -250,7 +240,6 @@ The decorations are defined as follows:
     -- Rotation can be "0", "90", "180", "270", or "random"
 
     place_offset_y = 0,
-    -- If the flag 'place_center_y' is set this parameter is ignored.
     -- Y offset of the schematic base node layer relative to the 'place_on'
     -- node.
     -- Can be positive or negative. Default is 0.
@@ -265,13 +254,3 @@ The decorations are defined as follows:
 This mod does not support adding ores to the caves, as this is a feature that
 is already well-supported by the Minetest Lua API and doesn't need a mod like
 this.
-
-## Misc
-
-In case you wish to do a few other operations, here's a few other functions
-that might be helpful to you:
-
-- `noordstar_caves.set_world_depth(h)` Set the world's depth to a given number.
-
-This feature is currently only supported in VoxeLibre. Contributions that help
-change the world depth in other games, are very welcome.

README.md

@@ -11,7 +11,7 @@ custom caves into the world and to lower the world depth.
 
 The mod has been tested on the following games:
 
-- [x] MineClone2
+- [x] VoxeLibre
 - [ ] Mineclonia
 - [ ] MTG
 

lua/timer.lua

@@ -1,139 +0,0 @@
-local internal = {
-    waypoints = {},
-    stats = {},
-    sessions = 0,
-    last = os.clock()
-}
-
-timer = {}
-
-function timer.start()
-    internal.waypoints = {}
-
-    internal.now()
-
-    internal.sessions = internal.sessions + 1
-end
-
-function timer.checkpoint(name)
-    local now = os.clock()
-
-    table.insert(internal.waypoints, { name, internal.last, now })
-
-    internal.now()
-end
-
-function timer.stop()
-    local name_len = 0
-
-    for _, t in ipairs(internal.waypoints) do
-        local name  = t[1]
-        local start = t[2]
-        local stop  = t[3]
-
-        local stat = internal.stats[name]
-
-        if stat then
-            internal.stats[name] = stat + (stop - start)
-        else
-            internal.stats[name] = stop - start
-        end
-
-        name_len = math.max(name_len, string.len(name))
-    end
-
-    local h1 = "Task"
-    local h2 = "Time"
-    local h3 = "Time (avg)"
-    
-    internal.log(
-        table.concat(
-            { h1
-            , string.rep(" ", name_len - string.len(h1))
-            , " | "
-            , h2
-            , string.rep(" ", 8 - string.len(h2))
-            , " | "
-            , h3
-            }
-            , ""
-        )
-    )
-
-    internal.log_hr(name_len)
-
-    for _, t in ipairs(internal.waypoints) do
-        local name = t[1]
-
-        internal.log_time(
-            name,
-            internal.to_ms(t[3] - t[2]),
-            internal.to_ms(internal.stats[name] / internal.sessions),
-            name_len
-        )
-    end
-
-    internal.log_hr(name_len)
-
-    internal.log_time("Total", internal.sum(), internal.sum_avg(), name_len)
-end
-
--- Log text to the Minetest chat
-function internal.log(text)
-    minetest.chat_send_all(os.time() .. " - " .. text)
-end
-
-function internal.log_hr(name_len)
-    internal.log(string.rep("-", name_len + 3 + 8 + 3 + 8))
-end
-
-function internal.log_time(header, time, time_avg, header_max_len)
-    local duration = tostring(time)
-    local duration_avg = tostring(time_avg)
-
-    internal.log(
-        table.concat(
-            { header
-            , string.rep(" ", header_max_len - string.len(header))
-            , " | "
-            , string.rep(" ", 5 - string.len(duration))
-            , duration
-            , " ms | "
-            , string.rep(" ", 5 - string.len(duration_avg))
-            , duration_avg
-            , " ms"
-            }
-            , ""
-        )
-    )
-end
-
-function internal.now()
-    internal.last = os.clock()
-end
-
-function internal.sum()
-    local s = 0
-
-    for _, t in ipairs(internal.waypoints) do
-        s = s + (t[3] - t[2])
-    end
-
-    return internal.to_ms(s)
-end
-
-function internal.sum_avg()
-    local s = 0
-    
-    for _, t in pairs(internal.stats) do
-        s = s + t
-    end
-
-    return internal.to_ms(s / internal.sessions)
-end
-
-function internal.to_ms(s)
-    return math.round(s * 1e3)
-end
-
-internal.now()

mod.conf

@@ -1,6 +1,6 @@
-name=noordstar_caves
+name=ns_cavegen
-description=A mod that adds more depths and caves to VoxeLibre or Mineclonia
+description=A custom cave generator engine
 author=Noordstar
-title=Noordstar Caves
+title=Cave Generator
-depends=mcl_init
+depends=
-optional_depends=mcl_init,mcl_worlds
+optional_depends=

script.lua

@@ -0,0 +1,926 @@
+-- This file is executed in the mapgen environment.
+
+-- Average size of each cave biome
+local BIOME_SIZE = { x = 250, y = 250, z = 250 }
+
+-- Average step size of connectivity params
+-- Given that connectivity is mostly a horizontal feature, it mostly changes
+-- on a vertical scale, and barely on a horizontal scale.
+local CONNECTIVITY_BLOB = { x =  250, y =  100, z =  250 }
+
+-- Point that is so out of the normal connectivity/verticality scope (0 - 100)
+-- that it is only selected when no other items are registered.
+local OUTLANDISH_POINT = -1e3
+
+-- Several seeds for mapgen
+local SEED_CONNECTIVITY   =  297948
+local SEED_HEAT           =  320523
+local SEED_HUMIDITY       = 9923473
+local SEED_VERTICALITY    =   35644
+
+-- Average step size of verticality params
+-- Given that verticality is mostly a vertical feature, it mostly changes on a
+-- horizontal scale, and barely on a vertical scale.
+local VERTICALITY_BLOB = { x =  100, y =  250, z =  100 }
+
+-- Lower bound for cave generation
+local WORLD_MINP = { x = -1e6, y = -1e6, z = -1e6 }
+
+-- Upper bound for cave generation
+local WORLD_MAXP = { x =  1e6, y =  1e6, z =  1e6 }
+
+local WORLD_DEPTH = -60
+
+local internal = {}
+
+-------------------------------------------------------------------------------
+-------------------------------------------------------------------------------
+-------------------------------- INTERNAL API ---------------------------------
+-------------------------------------------------------------------------------
+-------------------------------------------------------------------------------
+
+function internal.cave_vastness(pos)
+    local v = ns_cavegen.cave_vastness(pos)
+
+    if not v then
+        return 0
+    elseif v < 0 then
+        return 0
+    elseif v > 1 then
+        return 1
+    else
+        return v
+    end
+end
+
+-- Classify all nodes in the chunk into what they are
+function internal.classify_nodes(used_shapes, minp, maxp)
+    local sminp = vector.offset(minp,  1,  1,  1)
+    local smaxp = vector.offset(maxp, -1, -1, -1)
+    local sva = VoxelArea(sminp, smaxp)
+    local va = VoxelArea(minp, maxp)
+
+    local ceiling_decos = {}
+    local ceilings = {}
+    local contents = {}
+    local floor_decos = {}
+    local floors = {}
+    local walls = {}
+    
+    for i in sva:iterp(sminp, smaxp) do
+        local pos = sva:position(i)
+
+        if used_shapes[va:index(pos.x, pos.y, pos.z)] == true then
+            -- Part of cave
+            if not used_shapes[va:index(pos.x, pos.y + 1, pos.z)] then
+                table.insert(ceiling_decos, i)
+            elseif not used_shapes[va:index(pos.x, pos.y - 1, pos.z)] then
+                table.insert(floor_decos, i)
+            else
+                table.insert(contents, i)
+            end
+        else
+            -- Not part of cave
+            if used_shapes[va:index(pos.x, pos.y + 1, pos.z)] then
+                table.insert(floors, i)
+            elseif used_shapes[va:index(pos.x, pos.y - 1, pos.z)] then
+                table.insert(ceilings, i)
+            elseif used_shapes[va:index(pos.x - 1, pos.y, pos.z)] then
+                table.insert(walls, i)
+            elseif used_shapes[va:index(pos.x + 1, pos.y, pos.z)] then
+                table.insert(walls, i)
+            elseif used_shapes[va:index(pos.x, pos.y, pos.z - 1)] then
+                table.insert(walls, i)
+            elseif used_shapes[va:index(pos.x, pos.y, pos.z + 1)] then
+                table.insert(walls, i)
+            end
+        end
+    end
+
+    return {
+        ceiling_decos = ceiling_decos,
+        ceilings = ceilings,
+        contents = contents,
+        floor_decos = floor_decos,
+        floors = floors,
+        walls = walls,
+    }
+end
+
+function internal.clean_biome_def(def)
+    assert(type(def) == "table")
+    assert(type(def.name) == "string")
+    assert(type(def.heat_point) == "number")
+    assert(type(def.humidity_point) == "number")
+
+    def.y_min = def.y_min or (def.min_pos and def.min_pos.y) or WORLD_MINP.y
+    def.y_max = def.y_max or (def.max_pos and def.max_pos.y) or WORLD_MAXP.y
+
+    def.min_pos = def.min_pos or { x = WORLD_MINP.x, y = def.y_min, z = WORLD_MINP.z }
+    def.max_pos = def.max_pos or { x = WORLD_MAXP.x, y = def.y_max, z = WORLD_MAXP.z }
+
+    assert(type(def.y_min) == "number")
+    assert(type(def.y_max) == "number")
+    assert(type(def.min_pos) == "table")
+    assert(type(def.max_pos) == "table")
+    assert(type(def.min_pos.x) == "number")
+    assert(type(def.max_pos.x) == "number")
+    assert(type(def.min_pos.y) == "number")
+    assert(type(def.max_pos.y) == "number")
+    assert(type(def.min_pos.z) == "number")
+    assert(type(def.max_pos.z) == "number")
+
+    def.node_air = def.node_air or "air"
+
+    assert(def.node_dust == nil or type(def.node_dust) == "string")
+    assert(def.node_floor == nil or type(def.node_floor) == "string")
+    assert(def.node_wall == nil or type(def.node_wall) == "string")
+    assert(def.node_roof == nil or type(def.node_roof) == "string")
+    assert(type(def.node_air) == "string")
+
+    return def
+end
+
+function internal.clean_deco_def(def)
+    def.deco_type = def.deco_type or "simple"
+    def.place_on = def.place_on or "floor"
+    def.y_min = def.y_min or WORLD_MINP.y
+    def.y_max = def.y_max or WORLD_MAXP.y
+
+    assert(def.deco_type == "simple" or def.deco_type == "schematic")
+    assert(def.place_on == "floor" or def.place_on == "ceiling")
+    assert(type(def.fill_ratio) == "number")
+    assert(def.biomes == nil or type(def.biomes) == "table")
+
+    if def.deco_type == "simple" then
+        def.height = def.height or 1
+        def.height_max = def.height_max or def.height
+        def.place_offset_y = def.place_offset_y or 0
+
+        assert(type(def.deco_type) == "string")
+        assert(type(def.height) == "number")
+        assert(type(def.height_max) == "number")
+        assert(type(def.place_offset_y) == "number")
+
+    elseif def.deco_type == "schematic" then
+        def.replacements = def.replacements or {}
+        def.place_offset_y = def.place_offset_y or 0
+
+        assert(type(def.schematic) == "string" or type(def.schematic) == "table")
+        assert(type(def.replacements) == "table")
+        
+        assert(def.rotation == "0" or def.rotation == "90" or def.rotation == "180" or def.rotation == "270" or def.rotation == "random")
+        assert(type(def.place_offset_y) == "number")
+    end
+
+    return def
+end
+
+function internal.clean_shape_def(def)
+    assert(
+        type(def) == "table",
+        "Shape def is meant to be a table type"
+    )
+    assert(type(def.name) == "string", "Shape name is meant to be a string")
+    assert(type(def.connectivity_point) == "number")
+    assert(type(def.verticality_point) == "number")
+
+    def.y_min = def.y_min or WORLD_MINP.y
+    def.y_max = def.y_max or WORLD_MAXP.y
+
+    assert(type(def.y_min) == "number")
+    assert(type(def.y_max) == "number")
+    assert(def.noise_params == nil or type(def.noise_params) == "table")
+
+    return def
+end
+
+function internal.clear_registered_biomes()
+    ns_cavegen.registered_biomes = {}
+end
+
+function internal.clear_registered_decorations()
+    ns_cavegen.registered_decorations = {}
+end
+
+function internal.clear_registered_shapes()
+    ns_cavegen.registered_shapes = {}
+end
+
+-- Get connectivity noise params
+function internal.connectivity_noise_params()
+    local shapes = 0
+    for _, _ in pairs(ns_cavegen.registered_shapes) do
+        shapes = shapes + 1
+    end
+    local factor = math.max(1, math.abs(shapes) ^ 0.5)
+
+    return {
+        offset = 50,
+        scale = 50,
+        spread = {
+            x = factor * CONNECTIVITY_BLOB.x,
+            y = factor * CONNECTIVITY_BLOB.y,
+            z = factor * CONNECTIVITY_BLOB.z,
+        },
+        seed = SEED_CONNECTIVITY,
+        octaves = 2,
+        persistence = 0.2,
+        lacunarity = 2.0,
+        flags = "eased"
+    }
+end
+
+-- Get a default cave biome in case no biomes are registered
+function internal.default_biome()
+    return internal.clean_biome_def(
+        { name = "ns_cavegen:default_biome"
+        , heat_point = OUTLANDISH_POINT
+        , humidity_point = OUTLANDISH_POINT
+        }
+    )
+end
+
+-- Get a default cave shape in case no shapes are registered
+function internal.default_shape()
+    return internal.clean_shape_def(
+        { name = "ns_cavegen:none"
+        , connectivity_point = OUTLANDISH_POINT
+        , verticality_point = OUTLANDISH_POINT
+        }
+    )
+end
+
+-- Get a (sorta) Euclidian distance. The exact distance doesn't matter,
+-- it just needs to correctly determine whichever value is closer in a
+-- Euclidian space. Consequently, the square root is ignored as optimization.
+function internal.euclidian(x1, x2, y1, y2)
+    return (x1 - x2) ^ 2 + (y1 - y2) ^ 2
+end
+
+-- For each node, determine which cave biome they're in.
+function internal.find_biome_allocations(heat, humidity, va)
+    assert(#heat == #humidity)
+
+    local allocs = {}
+    local default_biome = internal.default_biome()
+
+    for i = 1, #heat, 1 do
+        local e, u = heat[i], humidity[i]
+        local d = internal.euclidian(
+            e, default_biome.heat_point,
+            u, default_biome.humidity_point
+        )
+        local biome_name
+
+        -- Find the appropriate biome
+        for name, def in pairs(ns_cavegen.registered_biomes) do
+            local def_d = internal.euclidian(
+                e, def.heat_point, u, def.humidity_point
+            )
+
+            if def_d < d then
+                local pos = va:position(i)
+                local contains_x = def.min_pos.x <= pos.x and pos.x <= def.max_pos.x
+                local contains_y = def.min_pos.y <= pos.y and pos.y <= def.max_pos.y
+                local contains_z = def.min_pos.z <= pos.z and pos.z <= def.max_pos.z
+
+                if contains_x and contains_y and contains_z then
+                    d = def_d
+                    biome_name = name
+                end
+            end
+        end
+
+        allocs[i] = biome_name
+    end
+
+    return allocs
+end
+
+-- For each node, determine which cave shape they follow.
+function internal.find_shape_allocations(connectivity, verticality, va)
+    assert(#connectivity == #verticality)
+
+    local allocs = {}
+    local default_shape = internal.default_shape()
+
+    for i = 1, #connectivity, 1 do
+        local c, v = connectivity[i], verticality[i]
+        local d = internal.euclidian(
+            c, default_shape.connectivity_point,
+            v, default_shape.verticality_point
+        )
+        local shape_name
+
+        -- Find the appropriate shape
+        for name, def in pairs(ns_cavegen.registered_shapes) do
+            local def_d = internal.euclidian(
+                c, def.connectivity_point, v, def.verticality_point
+            )
+
+            if def_d < d then
+                local y = va:position(i).y
+
+                if def.y_min <= y and y <= def.y_max then
+                    d = def_d
+                    shape_name = name
+                end
+            end
+        end
+
+        -- Assign the chosen name
+        allocs[i] = shape_name
+    end
+
+    return allocs
+end
+
+-- Once it has been figured out which node belongs to which shape,
+-- get noise values from the respective shapes.
+-- This function does its operations in-place.
+function internal.find_shape_values(used_shapes, minp, maxp, va)
+    -- Cache shapes so they don't need to be recalculated.
+    local captured_shapes = {}
+    local default_shape = internal.default_shape()
+
+    for i in va:iterp(minp, maxp) do
+        -- Get shape values per item
+        local name = used_shapes[i]
+        local shape
+
+        if name == nil then
+            shape = default_shape
+        else
+            shape = ns_cavegen.registered_shapes[name]
+        end
+
+        if captured_shapes[shape] == nil then
+            -- minetest.debug("Generating new shape! " .. shape.name)
+            captured_shapes[shape] = internal.generate_shape(shape, minp, maxp, va)
+        end
+
+        used_shapes[i] = captured_shapes[shape][i]
+        if used_shapes[i] == nil then
+            error(
+                "Noise value ended up nil unexpectedly: i = " .. i .. ", shape = " .. shape.name
+            )
+        end
+    end
+
+    -- minetest.debug("Finished generating shapes.")
+end
+
+function internal.generate_connectivity_noise(minp, maxp)
+    return internal.generate_perlin_noise(
+        internal.connectivity_noise_params(), minp, maxp
+    )
+end
+
+function internal.generate_heat_noise(minp, maxp)
+    return internal.generate_perlin_noise(
+        internal.heat_noise_params(), minp, maxp
+    )
+end
+
+function internal.generate_humidity_noise(minp, maxp)
+    return internal.generate_perlin_noise(
+        internal.humidity_noise_params(), minp, maxp
+    )
+end
+
+-- Generate Perlin noise within given boundaries
+function internal.generate_perlin_noise(noiseparams, minp, maxp)
+    local size = {
+        x = 1 + maxp.x - minp.x,
+        y = 1 + maxp.y - minp.y,
+        z = 1 + maxp.z - minp.z,
+    }
+
+    return PerlinNoiseMap(noiseparams, size):get_3d_map_flat(minp)
+end
+
+function internal.generate_shape(def, minp, maxp, va)
+    -- Get random noise if noise_params are given
+    if def.noise_params then
+        return internal.generate_perlin_noise(def.noise_params, minp, maxp)
+    else
+        local noise_flat = {}
+
+        for i in va:iterp(minp, maxp) do
+            noise_flat[i] = 0
+        end
+
+        return noise_flat
+    end
+end
+
+-- Generate verticality noise within given boundaries
+function internal.generate_verticality_noise(minp, maxp)
+    return internal.generate_perlin_noise(
+        internal.verticality_noise_params(), minp, maxp
+    )
+end
+
+-- Get the noise params for the cave biome temperature.
+function internal.heat_noise_params()
+    return {
+        offset = 50,
+        scale = 50,
+        spread = BIOME_SIZE,
+        seed = SEED_HEAT,
+        octaves = 2,
+        persistence = 0.1,
+        lacunarity = 2.0,
+        flags = ""
+    }
+end
+
+-- Get the noise params for the cave biome humidity.
+function internal.humidity_noise_params()
+    return { 
+        offset = 50,
+        scale = 50,
+        spread = BIOME_SIZE,
+        seed = SEED_HUMIDITY,
+        octaves = 2,
+        persistence = 0.1,
+        lacunarity = 2.0,
+        flags = ""
+    }
+end
+
+function internal.log_classified_nodes(classified_nodes)
+    minetest.debug("Found " .. #classified_nodes.ceiling_decos .. " ceiling decorations")
+    minetest.debug("Found " .. #classified_nodes.ceilings .. " ceiling nodes")
+    minetest.debug("Found " .. #classified_nodes.contents .. " content nodes")
+    minetest.debug("Found " .. #classified_nodes.floors .. " floor nodes")
+    minetest.debug("Found " .. #classified_nodes.floor_decos .. " floor decorations")
+    minetest.debug("Found " .. #classified_nodes.walls .. " wall nodes")
+end
+
+-- Take all necessary steps to execute the mapgen
+function internal.mapgen(vm, minp, maxp, blockseed)
+    -- Create bordered VoxelArea.
+    -- The point of this is so walls and ceilings can be determined using
+    -- bordering nodes in different chunks.
+    local bminp = vector.offset(minp, -1, -1, -1)
+    local bmaxp = vector.offset(maxp,  1,  1,  1)
+
+    -- Initiate VoxelArea objects
+    local va = VoxelArea(vm:get_emerged_area())
+    local bva = VoxelArea(bminp, bmaxp)
+    local sva = VoxelArea(minp, maxp)
+
+    -- Set seed
+    math.randomseed(blockseed)
+
+    -- Find cave shape params
+    local connectivity = internal.generate_connectivity_noise(bminp, bmaxp)
+    local verticality = internal.generate_verticality_noise(bminp, bmaxp)
+
+    -- Draw cave shapes
+    local used_shapes = internal.find_shape_allocations(connectivity, verticality, bva)
+    internal.find_shape_values(used_shapes, bminp, bmaxp, bva)
+    internal.shape_to_air(used_shapes, bminp, bmaxp, bva)
+
+    -- Find cave biome params
+    local heat = internal.generate_heat_noise(minp, maxp)
+    local humidity = internal.generate_humidity_noise(minp, maxp)
+
+    -- Classify various nodes as walls, floors, ceilings
+    local classified_nodes = internal.classify_nodes(used_shapes, bminp, bmaxp)
+    -- internal.log_classified_nodes(classified_nodes)
+
+    -- Draw cave biomes
+    local used_biomes = internal.find_biome_allocations(heat, humidity, sva)
+
+    -- Manipulate `data` table by adding classified nodes based on which biome
+    -- they're in.
+    local data = vm:get_data()
+    local ground = { [ minetest.CONTENT_AIR ] = false }
+
+    internal.write_classified_node(
+        data, va, used_biomes, classified_nodes.ceilings, sva, "node_roof",
+        ground
+    )
+    internal.write_classified_node(
+        data, va, used_biomes, classified_nodes.contents, sva, "node_air",
+        ground
+    )
+    internal.write_classified_node(
+        data, va, used_biomes, classified_nodes.floors, sva, "node_floor",
+        ground
+    )
+    internal.write_classified_node(
+        data, va, used_biomes, classified_nodes.walls, sva, "node_wall",
+        ground
+    )
+
+    -- Place floor decorations
+    -- In case the dust has not been defined, place air nodes first
+    internal.write_classified_node(
+        data, va, used_biomes, classified_nodes.floor_decos, sva, "node_air",
+        ground
+    )
+    internal.write_classified_node(
+        data, va, used_biomes, classified_nodes.floor_decos, sva, "node_dust",
+        ground
+    )
+    local claimed_floor = internal.write_simple_floor_decorations(
+        data, va, used_biomes, classified_nodes.floor_decos, sva
+    )
+
+    -- Place ceiling decorations
+    internal.write_classified_node(
+        data, va, used_biomes, classified_nodes.ceiling_decos, sva, "node_air",
+        ground
+    )
+    local claimed_ceiling = internal.write_simple_ceiling_decorations(
+        data, va, used_biomes, classified_nodes.ceiling_decos, sva
+    )
+
+    vm:set_data(data)
+
+    -- Set schematic decorations
+    internal.write_schematic_floor_decoration(
+        vm, used_biomes, classified_nodes.floor_decos, sva, claimed_floor
+    )
+    internal.write_schematic_ceiling_decoration(
+        vm, used_biomes, classified_nodes.ceiling_decos, sva, claimed_ceiling
+    )
+
+    -- vm:write_to_map()
+end
+
+-- Register a new biome
+function internal.register_biome(biome)
+    biome = internal.clean_biome_def(biome)
+    ns_cavegen.registered_biomes[biome.name] = biome
+end
+
+-- Register a new decoration
+function internal.register_decoration(deco)
+    table.insert(
+        ns_cavegen.registered_decorations,
+        internal.clean_deco_def(deco)
+    )
+end
+
+-- Register a new shape
+function internal.register_shape(shape)
+    shape = internal.clean_shape_def(shape)
+    ns_cavegen.registered_shapes[shape.name] = shape
+end
+
+-- Convert all shape noise into clarifications whether a node is wall or air.
+-- This function does its operations in-place.
+function internal.shape_to_air(noise_values, minp, maxp, va)
+    for i in va:iterp(minp, maxp) do
+        local vastness = internal.cave_vastness(va:position(i))
+
+        if noise_values[i] == nil then
+            error(
+                "Noise value ended up nil unexpectedly"
+            )
+        elseif noise_values[i] >= 1 - vastness then
+            noise_values[i] = true
+        else
+            noise_values[i] = false
+        end
+    end
+end
+
+-- Get verticality noise params
+function internal.verticality_noise_params()
+    local shapes = 0
+    for _, _ in pairs(ns_cavegen.registered_shapes) do
+        shapes = shapes + 1
+    end
+    local factor = math.max(1, math.abs(shapes) ^ 0.5)
+
+    return {
+        offset = 50,
+        scale = 50,
+        spread = {
+            x = factor * VERTICALITY_BLOB.x,
+            y = factor * VERTICALITY_BLOB.y,
+            z = factor * VERTICALITY_BLOB.z,
+        },
+        seed = SEED_VERTICALITY,
+        octaves = 2,
+        persistence = 0.2,
+        lacunarity = 2.0,
+        flags = "eased"
+    }
+end
+
+function internal.write_classified_node(vm_data, va, used_biomes, classified_nodes, small_va, biome_key, ground_content_nodes)
+    local default_biome = internal.default_biome()
+
+    local biome_to_id = {}
+    if default_biome[biome_key] == nil then
+        biome_to_id[default_biome.name] = ""
+    else
+        biome_to_id[default_biome.name] = minetest.get_content_id(default_biome[biome_key])
+    end
+
+    for _, i in ipairs(classified_nodes) do
+        local pos = small_va:position(i)
+        local biome = used_biomes[i] or default_biome.name
+
+        if biome_to_id[biome] == nil then
+            local biome_def
+
+            if biome == default_biome.name then
+                biome_def = default_biome
+            else
+                biome_def = ns_cavegen.registered_biomes[biome] or default_biome
+            end
+
+            if biome_def[biome_key] == nil then
+                biome_to_id[biome] = ""
+            else
+                biome_to_id[biome] = minetest.get_content_id(biome_def[biome_key]) or ""
+            end
+        end
+
+        local content_id = biome_to_id[biome]
+
+        if type(content_id) == "number" then
+            local vi = va:index(pos.x, pos.y, pos.z)
+            local vm_node = vm_data[vi]
+
+            if ground_content_nodes[vm_node] == nil then
+                local name = minetest.get_name_from_content_id(content_id)
+                ground_content_nodes[vm_node] = minetest.registered_nodes[name].is_ground_content or true
+            end
+
+            if ground_content_nodes[vm_node] then
+                vm_data[vi] = content_id
+            end
+        elseif content_id == "air" then
+            minetest.debug("Biome " .. biome .. "||| BREAAAK")
+            break
+        elseif content_id ~= "" and content_id ~= nil and content_id ~= "air" then
+            minetest.debug("Encountered content ID " .. content_id)
+        end
+    end
+end
+
+function internal.write_schematic_ceiling_decoration(vmanip, used_biomes, classified_nodes, sva, claimed_spots)
+    for _, def in pairs(ns_cavegen.registered_decorations) do
+        if def.deco_type == "schematic" and def.place_on == "ceiling" then
+            -- Place the decoration, if they're in the appropriate biome
+            for _, i in ipairs(classified_nodes) do
+                local good_biome = def.biomes == nil
+                local unclaimed_spot = true
+
+                for _, ci in ipairs(claimed_spots) do
+                    if ci == i then
+                        unclaimed_spot = false
+                        break
+                    end
+                end
+
+                if unclaimed_spot and not good_biome then
+                    local current_biome = used_biomes[i]
+                    for _, name in ipairs(def.biomes) do
+                        if name == current_biome then
+                            good_biome = true
+                            break
+                        end
+                    end
+                end
+
+                if unclaimed_spot and good_biome and math.random() < def.fill_ratio then
+                    -- Automatically place the top at the top of the cave
+                    local pos = sva:position(i)
+                    local h = def.schematic
+
+                    if type(def.schematic) == "string" then
+                        h = minetest.read_schematic(h, {})
+
+                        if type(h) == "nil" then
+                            error("Could not find schematic! Perhaps it the filename is incorrect?")
+                        end
+                    end
+
+                    h = h.size.y
+
+                    minetest.place_schematic_on_vmanip(vmanip,
+                        { x = pos.x, y = pos.y - h + 1 + def.place_offset_y, z = pos.z },
+                        def.schematic, def.rotation, def.replacement, true,
+                        def.flags
+                    )
+
+                    table.insert(claimed_spots, i)
+                end
+            end
+        end
+    end
+
+    return claimed_spots
+end
+
+function internal.write_schematic_floor_decoration(vmanip, used_biomes, classified_nodes, sva, claimed_spots)
+    for _, def in pairs(ns_cavegen.registered_decorations) do
+        if def.deco_type == "schematic" and def.place_on == "floor" then
+            -- Place the decoration, if they're in the appropriate biome
+            for _, i in ipairs(classified_nodes) do
+                local good_biome = def.biomes == nil
+                local unclaimed_spot = true
+
+                for _, ci in ipairs(claimed_spots) do
+                    if ci == i then
+                        unclaimed_spot = false
+                        break
+                    end
+                end
+
+                if unclaimed_spot and not good_biome then
+                    local current_biome = used_biomes[i]
+                    for _, name in ipairs(def.biomes) do
+                        if name == current_biome then
+                            good_biome = true
+                            break
+                        end
+                    end
+                end
+
+                if unclaimed_spot and good_biome and math.random() < def.fill_ratio then
+                    minetest.place_schematic_on_vmanip(
+                        vmanip, sva:position(i), def.schematic, def.rotation,
+                        def.replacement, true, def.flags
+                    )
+
+                    table.insert(claimed_spots, i)
+                end
+            end
+        end
+    end
+
+    return claimed_spots
+end
+
+function internal.write_simple_ceiling_decorations(vm_data, va, used_biomes, classified_nodes, sva)
+    local claimed_spots = {}
+
+    for _, def in pairs(ns_cavegen.registered_decorations) do
+        if def.deco_type == "simple" and def.place_on == "ceiling" then
+            -- Place the decoration, if they're in the appropriate biome.
+            for _, i in ipairs(classified_nodes) do
+                local pos = sva:position(i)
+                local good_biome = def.biomes == nil
+                local unclaimed_spot = true
+
+                for _, ci in ipairs(claimed_spots) do
+                    if ci == i then
+                        unclaimed_spot = false
+                        break
+                    end
+                end
+
+                if not good_biome and unclaimed_spot then
+                    local current_biome = used_biomes[i]
+                    for _, name in ipairs(def.biomes) do
+                        if name == current_biome then
+                            good_biome = true
+                            break
+                        end
+                    end
+                end
+
+                if unclaimed_spot and good_biome and math.random() < def.fill_ratio then
+                    -- Determine the height
+                    local height = def.height
+                    if def.height_max > height then
+                        height = math.min(
+                            16, math.random(def.height, def.height_max)
+                        )
+                    end
+
+                    -- Place the structure!
+                    for h = 1, height, 1 do
+                        local y = pos.y - h + def.place_offset_y + 1
+
+                        if sva:contains(pos.x, y, pos.z) then
+                            vm_data[va:index(pos.x, y, pos.z)] = minetest.get_content_id(def.decoration)
+                        end
+                    end
+
+                    table.insert(claimed_spots, i)
+                end
+            end
+        end
+    end
+
+    return claimed_spots
+end
+
+function internal.unregister_biome(name)
+    ns_cavegen.registered_biomes[name] = nil
+end
+
+function internal.unregister_shape(name)
+    ns_cavegen.registerd_shapes[name] = nil
+end
+
+function internal.write_simple_floor_decorations(vm_data, va, used_biomes, classified_nodes, sva)
+    local claimed_spots = {}
+
+    for _, def in pairs(ns_cavegen.registered_decorations) do
+        if def.deco_type == "simple" and def.place_on == "floor" then
+            -- Place the decoration, if they're in the appropriate biome.
+            for _, i in ipairs(classified_nodes) do
+                local pos = sva:position(i)
+                local good_biome = def.biomes == nil
+                local unclaimed_spot = true
+
+                for _, ci in ipairs(claimed_spots) do
+                    if ci == i then
+                        unclaimed_spot = false
+                        break
+                    end
+                end
+
+                if unclaimed_spot and not good_biome then
+                    local current_biome = used_biomes[i]
+                    for _, name in ipairs(def.biomes) do
+                        if name == current_biome then
+                            good_biome = true
+                            break
+                        end
+                    end
+                end
+
+                if unclaimed_spot and good_biome and math.random() < def.fill_ratio then
+                    -- Determine the height
+                    local height = def.height
+                    if def.height_max > height then
+                        height = math.min(
+                            16, math.random(def.height, def.height_max)
+                        )
+                    end
+                    
+                    -- Place the structure!
+                    for h = 1, height, 1 do
+                        local y = pos.y + h + def.place_offset_y - 1
+
+                        if sva:contains(pos.x, y, pos.z) then
+                            vm_data[va:index(pos.x, y, pos.z)] = minetest.get_content_id(def.decoration)
+                        end
+                    end
+
+                    table.insert(claimed_spots, i)
+                end
+            end
+        end
+    end
+
+    return claimed_spots
+end
+
+-------------------------------------------------------------------------------
+-------------------------------------------------------------------------------
+--------------------------------- PUBLIC API ----------------------------------
+-------------------------------------------------------------------------------
+-------------------------------------------------------------------------------
+
+minetest.register_on_generated(internal.mapgen)
+
+ns_cavegen = {
+    cave_vastness = function(pos)
+        if pos.y > 0 or pos.y < WORLD_DEPTH then
+            return 0
+        end
+
+        local y = math.abs(pos.y)
+        local d = math.abs(WORLD_DEPTH / 2)
+        return 1 - (math.abs(y - d) / d)
+    end,
+
+    clear_registered_biomes = internal.clear_registered_biomes,
+
+    clear_registered_decorations = internal.clear_registered_decorations,
+
+    clear_registered_shapes = internal.clear_registered_shapes,
+
+    register_biome = internal.register_biome,
+
+    register_decoration = internal.register_decoration,
+
+    register_shape = internal.register_shape,
+
+    registered_biomes = {},
+
+    registered_decorations = {},
+
+    registered_shapes = {},
+
+    unregister_biome = internal.unregister_biome,
+
+    unregister_shape = internal.unregister_shape,
+}
+
+-- dofile(minetest.get_modpath(minetest.get_current_modname()) .. "/lua/register.lua")