ns_cavegen/lua/engine.lua

473 lines
14 KiB
Lua

-- Constants and magic numbers
local mapgen_buffer = 16
-- Convert 3d relative coordinates to an index on a flat array
local function from_3d_to_flat(dx, dy, dz, nx, ny)
return (nx * ny * dz) + (nx * dy) + dx + 1
end
-- Convert an index on a flat array to 3d relative coordinates
local function from_flat_to_3d(i, nx, ny)
return {
dx = (i - 1) % nx,
dy = math.floor((i - 1) / nx) % ny,
dz = math.floor((i - 1) / (nx * ny))
}
end
-- Iterate over a 3d area, both indexing by the index and the ansolute position
local function iter_3d_area(minp, maxp, callback)
local nx = maxp.x - minp.x + 1
local ny = maxp.y - minp.y + 1
local nz = maxp.z - minp.z + 1
for i = 1, nx * ny * nz do
local dpos = from_flat_to_3d(i, nx, ny)
local pos = {
x = minp.x + dpos.dx,
y = minp.y + dpos.dy,
z = minp.z + dpos.dz,
}
callback(i, pos)
end
end
-- Helper function to convert a set of coordinates to a readable string
local function pos_to_str(pos)
return "(" .. pos.x .. ", " .. pos.y .. ", " .. pos.z .. " )"
end
local Flat3dArray = {}
Flat3dArray.__index = Flat3dArray
function Flat3dArray:new(minp, maxp, arr)
local instance = {}
setmetatable(instance, Flat3dArray)
local nx = maxp.x - minp.x + 1
local ny = maxp.y - minp.y + 1
local nz = maxp.z - minp.z + 1
if #arr ~= nx * ny * nz then
error(
"Input array doesn't match dimension lengths: " .. nx .. " x " ..
ny .. " x " .. nz .. " = " .. (nx*ny*nz) .. ", but found " .. #arr
)
end
instance.nx = nx
instance.ny = ny
instance.nz = nz
instance.minp = minp
instance.maxp = maxp
instance.arr = arr
return instance
end
function Flat3dArray:from_func(minp, maxp, callback)
local arr = {}
iter_3d_area(minp, maxp, function (i, pos)
arr[i] = callback(i, pos)
end)
return self:new(minp, maxp, arr)
end
function Flat3dArray:get_index(i)
local out = self.arr[i]
if out == nil then
error(
"Index " .. i .. " not found in array of length " .. #self.arr
)
end
return out
end
function Flat3dArray:get_pos(pos)
self:validate_pos(pos)
local dx = pos.x - self.minp.x
local dy = pos.y - self.minp.y
local dz = pos.z - self.minp.z
return self:get_index(from_3d_to_flat(dx, dy, dz, self.nx, self.ny))
end
local function is_valid_pos(pos, minp, maxp)
if pos.x < minp.x then
return false
elseif pos.x > maxp.x then
return false
elseif pos.y < minp.y then
return false
elseif pos.y > maxp.y then
return false
elseif pos.z < minp.z then
return false
elseif pos.z > maxp.z then
return false
else
return true
end
end
function Flat3dArray:valid_pos(pos)
return is_valid_pos(pos, self.minp, self.maxp)
end
function Flat3dArray:validate_pos(pos)
if not self:valid_pos(pos) then
error(
table.concat(
{ "Position "
, pos_to_str(pos)
, " out of bounds from minp = "
, pos_to_str(self.minp)
, ", maxp = "
, pos_to_str(self.maxp)
},
""
)
)
end
end
-- Get an enhanced function from the def function that warns us when the
-- function does not behave properly
local function enhanced_func(def)
if type(def.name) ~= "string" then
error("Invalid nameless shape definition")
elseif type(def.func) ~= "function" then
error(
"Invalid shape definition misses an adjustment function"
)
else
return function(pos, n)
local out = def.func(pos, n)
if type(out) == "number" then
return out
elseif n == nil then
error(
"Shape " .. def.name .. " function must return a number. The input `n` was nil. Perhaps your `noise_params` field is invalid?"
)
else
error("Shape " .. def.name .. " function must return a number.")
end
end
end
end
-- Get a flat array of cave shape noise values from a given cave shape def
local function get_flat_from_shape_def(def, minp, maxp)
local f = enhanced_func(def)
local nx = maxp.x - minp.x + 1
local ny = maxp.y - minp.y + 1
local nz = maxp.z - minp.z + 1
local noise_flat_map = {}
-- If noise parameters have been defined, fill the table with noise
-- If not, all values remain nil
if def.noise_params ~= nil then
local p = PerlinNoiseMap(def.noise_params, { x = nx, y = ny, z = nz })
if nz == 1 then
p:get_2d_map_flat(minp, noise_flat_map)
else
p:get_3d_map_flat(minp, noise_flat_map)
end
end
iter_3d_area(minp, maxp, function(i, pos)
noise_flat_map[i] = f(pos, noise_flat_map[i])
end)
return Flat3dArray:new(minp, maxp, noise_flat_map)
end
local function get_flat_from_noise_params(minp, maxp, noise_params)
local nx = maxp.x - minp.x + 1
local ny = maxp.y - minp.y + 1
local nz = maxp.z - minp.z + 1
local buffer = {}
local p = PerlinNoiseMap(noise_params, { x = nx, y = ny, z = nz })
if nz == 1 then
p:get_2d_map_flat(minp, buffer)
else
p:get_3d_map_flat(minp, buffer)
end
return Flat3dArray:new(minp, maxp, buffer)
end
-- Based on the number of cave shapes, calculate how quickly connectivity is
-- meant to change
local function get_connectivity_noise_params(shape_size)
local factor = math.max(math.abs(shape_size) ^ 0.5, 1)
return {
offset = 50,
scale = 50,
spread = { x = factor * 250, y = factor * 100, z = factor * 250 },
seed = 297948,
octaves = 2,
persistence = 0.2,
lacunarity = 2.0,
flags = "eased"
}
end
-- Based on the number of cave shapes, calculate how quickly verticality is
-- meant to change
local function get_verticality_noise_params(shape_size)
local factor = math.max(math.abs(shape_size) ^ 0.5, 1)
return {
offset = 50,
scale = 50,
spread = { x = factor * 100, y = factor * 250, z = factor * 100 },
seed = 35644,
octaves = 2,
persistence = 0.2,
lacunarity = 2.0,
flags = "eased"
}
end
-- Get the distance of each cave shape to calculate their weight.
local function shape_distance_weight(shape_size, dx, dy)
local factor = math.max(math.abs(shape_size) ^ 0.5, 1)
local max_distance = 100 / factor
if dx^2 + dy^2 > max_distance^2 then
return 0
else
return 1 / (dx^5 + dy^5)
end
end
-- Get a flat map containing all flat threshold values
local function get_threshold_flat(minp, maxp)
local connectivity = get_flat_from_noise_params(
minp, maxp,
get_connectivity_noise_params(#noordstar_caves.registered_shapes)
)
local verticality = get_flat_from_noise_params(
minp, maxp,
get_verticality_noise_params(#noordstar_caves.registered_shapes)
)
local noise = {}
-- Get noise for all cave shapes
for key, def in pairs(noordstar_caves.registered_shapes) do
noise[key] = {
key = key,
noise = get_flat_from_shape_def(def, minp, maxp),
def = def
}
end
-- Create the flat array
return Flat3dArray:from_func(minp, maxp, function(i, pos)
local total = 0
local count = 0
local x = connectivity:get_pos(pos)
local y = verticality:get_pos(pos)
for _, n in pairs(noise) do
local v = n.noise:get_pos(pos)
local dx = math.abs(x - n.def.connectivity_point)
local dy = math.abs(y - n.def.verticality_point)
local w = math.abs(shape_distance_weight(
#noordstar_caves.registered_shapes, dx, dy
))
total = total + v * w
count = count + w
end
if count <= 0 then
return -1000
else
return total / count
end
end)
end
-- Old minimum height for the overworld
local old_overworld_min = mcl_vars.mg_overworld_min
-- If another mod doesn't override the maximum world depth, we will assume that
-- the world depth is the following value.
local world_depth = -60
-- Otherwise, this variable can be changed using the following function,
-- which will also update all the other necessary variables
function noordstar_caves.set_world_depth(h)
-- Set world depth variable
world_depth = h
end
noordstar_caves.set_world_depth(world_depth)
-- The `cave_vastness` is a variable that determines the size of caves.
-- The function takes in an x, y and z variable, and returns a number between
-- 0 and 1.
-- Low numbers mean very rare and tiny caves, while high numbers mean massive
-- caves, with massive open spaces.
-- If you wish to overwrite this function, it is good to keep in mind to:
-- - Make sure that the output changes VERY SLOWLY over time
-- - This function will be run a LOT so it is very performance sensitive
noordstar_caves.cave_vastness = function(pos)
return pos.y / world_depth
end
-- Secretly, we're using an internal function that also adds a safe layer for
-- when we're approaching bedrock levels
local function cave_vastness(pos)
if world_depth + 20 < pos.y then
return noordstar_caves.cave_vastness(pos)
elseif world_depth + 5 < pos.y then
return noordstar_caves.cave_vastness(pos) * math.abs(pos.y - world_depth - 5) / 15
else
return 0
end
end
-- Get a flat array of nodes that are either in caves or not in caves
local function get_flat_cave_bools(minp, maxp)
local thresholds = get_threshold_flat(minp, maxp)
return Flat3dArray:from_func(minp, maxp, function(i, pos)
return thresholds:get_pos(pos) >= 1 - cave_vastness(pos)
end)
end
local node_type =
{ unknown = 1 -- Edge of a chunk
, floor = 2 -- Floor of a cave
, wall = 3 -- Side wall of a cave
, roof = 4 -- Roof of a cave
, content = 5 -- Air in the cave not adjacent to a wall, floor or roof
, stone = 6 -- Underground node not adjacent to a cave
}
local function get_flat_cave_node_types(minp, maxp)
local bools = get_flat_cave_bools(minp, maxp)
return Flat3dArray:from_func(minp, maxp, function (i, pos)
if bools:get_pos(pos) then
return node_type.content
-- Floor takes precedence
elseif pos.y == maxp.y then -- Could be floor
return node_type.unknown
elseif bools:get_pos({ x = pos.x, y = pos.y + 1, z = pos.z }) then
return node_type.floor
-- Then roof takes precedence
elseif pos.y == minp.y then -- Could be roof
return node_type.unknown
elseif bools:get_pos({ x = pos.x, y = pos.y - 1, z = pos.z }) then
return node_type.roof
else
-- Check for walls
local left = { x = pos.x - 1, y = pos.y, z = pos.z }
local right = { x = pos.x + 1, y = pos.y, z = pos.z }
local front = { x = pos.x, y = pos.y, z = pos.z - 1 }
local back = { x = pos.x, y = pos.y, z = pos.z + 1 }
-- Check if the value is near the edge
local on_edge = false
if left.x < minp.x then
on_edge = true
elseif bools:get_pos(left) then
return node_type.wall
end
if right.x > maxp.x then
on_edge = true
elseif bools:get_pos(right) then
return node_type.wall
end
if front.z < minp.z then
on_edge = true
elseif bools:get_pos(front) then
return node_type.wall
end
if back.z > maxp.z then
on_edge = true
elseif bools:get_pos(back) then
return node_type.wall
end
if on_edge then
return node_type.unknown
else
return node_type.stone
end
end
end)
end
minetest.register_on_generated(function(minp, maxp, blockseed)
local vminp =
{ x = minp.x - mapgen_buffer
, y = minp.y - mapgen_buffer
, z = minp.z - mapgen_buffer
}
local vmaxp =
{ x = maxp.x + mapgen_buffer
, y = maxp.y + mapgen_buffer
, z = maxp.z + mapgen_buffer
}
-- Get voxelmanip
local vm = minetest.get_mapgen_object("voxelmanip")
local flat_data = Flat3dArray:new(vminp, vmaxp, vm:get_data())
-- Get threshold values
local node_types = get_flat_cave_node_types(vminp, vmaxp)
local node_air = minetest.get_content_id("air")
local node_floor = minetest.get_content_id("mcl_core:glass_green")
local node_wall = minetest.get_content_id("mcl_core:glass_purple")
local node_roof = minetest.get_content_id("mcl_core:glass_red")
local node_other = minetest.get_content_id("mcl_core:glass")
local nids = Flat3dArray:from_func(vminp, vmaxp, function(i, pos)
local nt = node_types:get_pos(pos)
if not is_valid_pos(pos, minp, maxp) then
return flat_data:get_pos(pos)
elseif nt == node_type.unknown then
return node_other
elseif nt == node_type.floor then
return node_floor
elseif nt == node_type.wall then
return node_wall
elseif nt == node_type.roof then
return node_roof
elseif nt == node_type.content then
return node_air
elseif nt == node_type.stone then
return flat_data:get_pos(pos)
end
end)
-- Write all changes to the Minetest world
vm:set_data(nids.arr)
vm:write_to_map()
end)