mapgen_rivers/pregenerate.lua

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local modpath = minetest.get_modpath(minetest.get_current_modname())
local EvolutionModel = dofile(modpath .. '/terrainlib_lua/erosion.lua')
local twist = dofile(modpath .. '/terrainlib_lua/twist.lua')
local blocksize = tonumber(mapgen_rivers.settings:get("blocksize"))
local tectonic_speed = tonumber(mapgen_rivers.settings:get("tectonic_speed"))
local np_base = mapgen_rivers.settings:get_np_group("np_base")
np_base.spread.x = np_base.spread.x / blocksize
np_base.spread.y = np_base.spread.y / blocksize
np_base.spread.z = np_base.spread.z / blocksize
local evol_params = {
K = tonumber(mapgen_rivers.settings:get("river_erosion_coef")),
m = tonumber(mapgen_rivers.settings:get("river_erosion_power")),
d = tonumber(mapgen_rivers.settings:get("difusive_erosion")),
}
local time = tonumber(mapgen_rivers.settings:get("evol_time"))
local time_step = tonumber(mapgen_rivers.settings:get("evol_time_step"))
local niter = math.ceil(time/time_step)
time_step = time / niter
-- Setup the model
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local size = {
x = tonumber(mapgen_rivers.settings:get("grid_x_size")),
y = tonumber(mapgen_rivers.settings:get("grid_z_size")),
}
local seed = tonumber(minetest.get_mapgen_setting("seed"))
np_base.seed = (np_base.seed or 0) + seed
local nobj_base = PerlinNoiseMap(np_base, {x=size.x, y=1, z=size.y})
local dem = nobj_base:get_3d_map_flat({x=0, y=0, z=0})
dem.X = size.x
dem.Y = size.y
local model = EvolutionModel(evol_params)
model.dem = dem
local ref_dem = model:define_isostasy(dem)
local tectonic_step = tectonic_speed * time_step
collectgarbage()
-- Run the model
for i=1, niter do
minetest.log("info", "[mapgen_rivers] Iteration " .. i .. " of " .. niter)
model:diffuse(time_step)
model:flow()
model:erode(time_step)
if i < niter then
if tectonic_step ~= 0 then
nobj_base:get_3d_map_flat({x=0, y=tectonic_step*i, z=0}, ref_dem)
end
model:isostasy()
end
collectgarbage()
end
model:flow()
local mfloor = math.floor
local mmin, mmax = math.min, math.max
local offset_x, offset_y = twist(model.dirs, model.rivers, 5)
for i=1, size.x*size.y do
offset_x[i] = mmin(mmax(offset_x[i]*256, -128), 127)
offset_y[i] = mmin(mmax(offset_y[i]*256, -128), 127)
end
-- Write the results in the world directory
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local datapath = minetest.get_worldpath() .. "/river_data/"
minetest.mkdir(datapath)
local function write_map(filename, data, bytes)
local size = #data
local file = io.open(datapath .. filename, 'wb')
local bytelist = {}
for j=1, bytes do
bytelist[j] = 0
end
local unpk = unpack
local schar = string.char
local floor = math.floor
for i=1, size do
local n = floor(data[i])
data[i] = n
for j=bytes, 2, -1 do
bytelist[j] = n % 256
n = floor(n / 256)
end
bytelist[1] = n % 256
file:write(schar(unpk(bytelist)))
end
file:close()
end
write_map('dem', model.dem, 2)
write_map('lakes', model.lakes, 2)
write_map('dirs', model.dirs, 1)
write_map('rivers', model.rivers, 4)
write_map('offset_x', offset_x, 1)
write_map('offset_y', offset_y, 1)
local sfile = io.open(datapath .. 'size', "w")
sfile:write(size.x..'\n'..size.y)
sfile:close()
local use_interactive_loader
if minetest.settings:has("mapgen_rivers_use_interactive_loader") then
use_interactive_loader = minetest.settings:get_bool("mapgen_rivers_use_interactive_loader")
else
use_interactive_loader = not minetest.settings:get_bool("mapgen_rivers_load_all")
end
if not use_interactive_loader then
mapgen_rivers.grid = {
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size = size,
dem = model.dem,
lakes = model.lakes,
dirs = model.dirs,
rivers = model.rivers,
offset_x = offset_x,
offset_y = offset_y,
}
end