Add biomeinfo mod

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Wuzzy 2019-09-11 16:06:34 +02:00
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# Biome Info API
This document explains the API of this mod.
## v6 mapgen functions
These are functions for the v6 mapgen only.
Use these functions only in worlds in which the v6 mapgen is used.
If you use these in any other mapgen, bad things might happen.
### `biomeinfo.get_v6_humidity(pos)`
Get the biome humidity at pos (for v6 mapgen).
### `biomeinfo.get_v6_heat(pos)`
Get the biome heat/temperature at pos (for v6 mapgen).
### `biomeinfo.get_v6_biome(pos)`
Get the v6 biome at pos.
Returns a string, which is the unique biome name.
Note: This function currently ignores the `biomeblend` v6 mapgen flag,
it just pretends this setting is disabled.
This is normally not a problem, but at areas where biomes blend,
the result is not perfectly accurate and just an estimate.
### `biomeinfo.get_active_v6_biomes()`
Returns a table containing the names of all v6 biomes that are actively
used in the current world, e.g. those that have been activated
by the use of the mapgen v6 flags (`mgv6_spflags`).
### `biomeinfo.all_v6_biomes`
This is a table containing all v6 biomes (as strings), even those that
might not be used in the current world.
### v6 biome names
These are the biome names used in this mod:
* Normal
* Desert
* Jungle
* Tundra
* Taiga

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# Biome Info API [`biomeinfo`]
This is an API mod for mod developers to add a couple of missing
biome-related functions.
Currently, this mod only adds v6-related functions.
Most importantly, you can get the heat, humidity and biome in the v6 mapgen.
See `API.md` for the API documentation.
Current version: 1.0.1 (this is a [SemVer](https://semver.org/))
License: MIT License

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biomeinfo = {}
-- Copied from mapgen_v6.h
local MGV6_FREQ_HOT = 0.4
local MGV6_FREQ_SNOW = -0.4
local MGV6_FREQ_TAIGA = 0.5
local MGV6_FREQ_JUNGLE = 0.5
-- Biome types
local BT_NORMAL = "Normal"
local BT_TUNDRA = "Tundra"
local BT_TAIGA = "Taiga"
local BT_DESERT = "Desert"
local BT_JUNGLE = "Jungle"
-- Get mapgen settings
local seed = tonumber(minetest.get_mapgen_setting("seed")) or 0
local mgv6_perlin_biome, mgv6_perlin_humidity, mgv6_np_biome
local v6_flags_str = minetest.get_mapgen_setting("mgv6_spflags")
if v6_flags_str == nil then
v6_flags_str = ""
end
local v6_flags = string.split(v6_flags_str)
local v6_use_snow_biomes = true
local v6_use_jungles = true
-- TODO: Implement biome blend.
-- Currently we pretend biome blend is disabled.
-- This just makes the calculations inaccurate near biome boundaries,
-- but should be fine otherwise.
local v6_use_biome_blend = false
for f=1, #v6_flags do
local flag = v6_flags[f]:trim()
if flag == "nosnowbiomes" then
v6_use_snow_biomes = false
end
if flag == "snowbiomes" then
v6_use_snow_biomes = true
end
if flag == "nojungles" then
v6_use_jungles = false
end
if flag == "jungles" then
v6_use_jungles = true
end
if flag == "nobiomeblend" then
v6_use_biome_blend = false
end
-- TODO
-- if flag == "biomeblend" then
-- v6_use_biome_blend = true
-- end
end
-- Force-enable jungles when snowbiomes flag is set
if v6_use_snow_biomes then
v6_use_jungles = true
end
local v6_freq_desert = tonumber(minetest.get_mapgen_setting("mgv6_freq_desert") or 0.45)
local NOISE_MAGIC_X = 1619
local NOISE_MAGIC_Y = 31337
local NOISE_MAGIC_Z = 52591
local NOISE_MAGIC_SEED = 1013
local noise2d = function(x, y, seed)
-- TODO: implement noise2d function for biome blend
return 0
--[[
local n = (NOISE_MAGIC_X * x + NOISE_MAGIC_Y * y
+ NOISE_MAGIC_SEED * seed) & 0x7fffffff;
n = (n >> 13) ^ n;
n = (n * (n * n * 60493 + 19990303) + 1376312589) & 0x7fffffff;
return 1.0 - n / 0x40000000;
]]
end
biomeinfo.all_v6_biomes = {
BT_NORMAL,
BT_DESERT,
BT_JUNGLE,
BT_TUNDRA,
BT_TAIGA
}
local function init_perlins()
if not mgv6_perlin_biome then
mgv6_np_biome = minetest.get_mapgen_setting_noiseparams("mgv6_np_biome")
if mgv6_np_biome then
mgv6_perlin_biome = minetest.get_perlin(mgv6_np_biome)
end
end
if not mgv6_perlin_humidity then
local np_humidity = minetest.get_mapgen_setting_noiseparams("mgv6_np_humidity")
if np_humidity then
mgv6_perlin_humidity = minetest.get_perlin(np_humidity)
end
end
end
function biomeinfo.get_active_v6_biomes()
local biomes = { BT_NORMAL, BT_DESERT }
if v6_use_jungles then
table.insert(biomes, BT_JUNGLE)
end
if v6_use_snow_biomes then
table.insert(biomes, BT_TUNDRA)
table.insert(biomes, BT_TAIGA)
end
return biomes
end
function biomeinfo.get_v6_heat(pos)
init_perlins()
local bpos = vector.floor(pos)
-- The temperature noise needs a special offset (see calculateNoise in mapgen_v6.cpp)
return mgv6_perlin_biome:get_2d({x=bpos.x + mgv6_np_biome.spread.x*0.6, y=bpos.z + mgv6_np_biome.spread.z*0.2})
end
function biomeinfo.get_v6_humidity(pos)
init_perlins()
local bpos = vector.floor(pos)
return mgv6_perlin_humidity:get_2d({x=bpos.x, y=bpos.z})
end
-- Returns the v6 biome at pos.
-- Returns a string representing the biome name.
function biomeinfo.get_v6_biome(pos)
init_perlins()
local bpos = vector.floor(pos)
-- Based on the algorithm MapgenV6::getBiome in mapgen_v6.cpp
local pos2d = {x=bpos.x, y=bpos.z}
if not mgv6_perlin_biome or not mgv6_perlin_humidity then
return "???"
end
local d = biomeinfo.get_v6_heat(bpos)
local h = biomeinfo.get_v6_humidity(bpos)
if (v6_use_snow_biomes) then
local blend
if v6_use_biome_blend then
blend = noise2d(pos2d.x, pos2d.y, seed) / 40
else
blend = 0
end
if (d > MGV6_FREQ_HOT + blend) then
if (h > MGV6_FREQ_JUNGLE + blend) then
return BT_JUNGLE
end
return BT_DESERT
end
if (d < MGV6_FREQ_SNOW + blend) then
if (h > MGV6_FREQ_TAIGA + blend) then
return BT_TAIGA
end
return BT_TUNDRA
end
return BT_NORMAL
end
if (d > v6_freq_desert) then
return BT_DESERT
end
if ((v6_use_biome_blend) and (d > v6_freq_desert - 0.10) and
((noise2d(pos2d.x, pos2d.y, seed) + 1.0) > (v6_freq_desert - d) * 20.0)) then
return BT_DESERT
end
if ((v6_use_jungles) and (h > 0.75)) then
return BT_JUNGLE
end
return BT_NORMAL
end

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name = biomeinfo
description = Simple API to get data about biomes.