kingdoms_game/mods/utils/noisemanager.lua

--[[
Copyright (c) 2014, Robert 'Bobby' Zenz
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--- The NoiseManager manages seeds and creates PRNG of various kinds, always
-- with a new, unique seed. The seed is incremented with each creation, so
-- it is guaranteed that the results are reproducable.
NoiseManager = {}


--- Creates a new instance of NoiseManager.
--
-- @param start_seed Optional. The initial seed value, defaults to 0.
-- @param size_x Optional. The map size in the x direction, defaults to
--               the mapchunk size (see blockutil.MAPCHUNK_SIZE).
-- @param size_y Optional. The map size in the y direction, defaults to size_x.
-- @param size_z Optional. The map size in the z direction, defaults to size_z.
-- @return A new instance of NoiseManager.
function NoiseManager:new(start_seed, size_x, size_y, size_z)
	local instance = {
		map_size = {
			x = size_x or blockutil.MAPCHUNK_SIZE,
			y = size_y or size_x or blockutil.MAPCHUNK_SIZE,
			z = size_z or size_x or blockutil.MAPCHUNK_SIZE
		},
		next_seed = start_seed or 0
	}
	
	setmetatable(instance, self)
	self.__index = self
	
	return instance
end


--- Creates a Perlin object with the given values.
--
-- @param octaves The count of octaves.
-- @param persistence The persistence values.
-- @param scale The scale.
-- @return The new Perlin object.
function NoiseManager:get_noise(octaves, persistence, scale)
	self.next_seed = self.next_seed + 1
	
	return minetest.get_perlin(self.next_seed, octaves, persistence, scale)
end

-- Creates a PerlinMap object with the given values suitable for 2D noise.
--
-- @param octaves The count of octaves.
-- @param persistence The persistence value.
-- @param scale The scale.
-- @param spreadx The spread of the x axis.
-- @param spready Optional. The spread of the y axis, defaults to spreadx.
-- @param flags Optional. Additional flags for the noise.
-- return The new PerlinMap object.
function NoiseManager:get_map2d(octaves, persistence, scale, spreadx, spready, flags)
	return self:get_map3d(octaves, persistence, scale, spreadx, spready, 1, flags)
end

-- Creates a PerlinMap object with the given values suitable for 3D noise.
--
-- @param octaves The count of octaves.
-- @param persistence The persistence value.
-- @param scale The scale.
-- @param spreadx The spread of the x axis.
-- @param spready Optional. The spread of the y axis, defaults to spreadx.
-- @param spreadz Optional. The spread of the z axis, defaults to spreadx.
-- @param flags Optional. Additional flags for the noise.
-- return The new PerlinMap object.
function NoiseManager:get_map3d(octaves, persistence, scale, spreadx, spready, spreadz, flags)
	self.next_seed = self.next_seed + 1
	
	local parameters = {
		offset = 0,
		scale = scale,
		spread = {
			x = spreadx,
			y = spready or spreadx,
			z = spreadz or spreadx
		},
		seed = self.next_seed,
		octaves = octaves,
		persist = persistence,
		flags = flags
	}
	
	return minetest.get_perlin_map(parameters, self.map_size)
end

--- Gets the next seed that will be used. Does not increment the counter.
--
-- @return The next seed that will be used.
function NoiseManager:get_next_seed()
	return self.next_seed
end

--- Creates a PcgRandom object.
--
-- @return The new PcgRandom object.
function NoiseManager:get_pcgrandom()
	self.next_seed = self.next_seed + 1
	
	return PcgRandom(self.next_seed)
end

--- Creates a PseudoRandom object.
--
-- @return The new PseudoRandom object.
function NoiseManager:get_random()
	self.next_seed = self.next_seed + 1
	
	return PseudoRandom:new(self.next_seed)
end