mapgen_rivers/pregenerate.lua

117 lines
3.1 KiB
Lua

-- Generate the grid using terrainlib_lua
-- Only called on first mapgen, if there is no grid yet
local EvolutionModel = dofile(mapgen_rivers.modpath .. '/terrainlib_lua/erosion.lua')
local twist = dofile(mapgen_rivers.modpath .. '/terrainlib_lua/twist.lua')
local blocksize = mapgen_rivers.settings.blocksize
local tectonic_speed = mapgen_rivers.settings.tectonic_speed
local np_base = table.copy(mapgen_rivers.noise_params.base)
np_base.spread = vector.divide(np_base.spread, blocksize)
local evol_params = mapgen_rivers.settings.evol_params
local time = mapgen_rivers.settings.evol_time
local time_step = mapgen_rivers.settings.evol_time_step
local niter = math.ceil(time/time_step)
time_step = time / niter
local use_margin = mapgen_rivers.settings.margin
local margin_width = mapgen_rivers.settings.margin_width / blocksize
local margin_elev = mapgen_rivers.settings.margin_elev
local function margin(dem, width, elev)
local X, Y = dem.X, dem.Y
for i=1, width do
local c1 = ((i-1)/width) ^ 0.5
local c2 = (1-c1) * elev
local index = (i-1)*X + 1
for x=1, X do
dem[index] = dem[index] * c1 + c2
index = index + 1
end
index = i
for y=1, Y do
dem[index] = dem[index] * c1 + c2
index = index + X
end
index = X*(Y-i) + 1
for x=1, X do
dem[index] = dem[index] * c1 + c2
index = index + 1
end
index = X-i + 1
for y=1, Y do
dem[index] = dem[index] * c1 + c2
index = index + X
end
end
end
function mapgen_rivers.pregenerate(grid)
local size = grid.size
if size.x * size.y > 4e6 then
minetest.log("warning", "[mapgen_rivers] You are going to generate a very large grid (>4M nodes). If you experience problems, you should increase blocksize or reduce map size.")
end
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
if use_margin then
margin(dem, margin_width, margin_elev)
end
local model = EvolutionModel(evol_params)
model.dem = dem
local ref_dem = model:define_isostasy(dem)
local tectonic_step = tectonic_speed * time_step
collectgarbage()
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)
if use_margin then
margin(ref_dem, margin_width, margin_elev)
end
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
grid.dem = model.dem
grid.lakes = model.lakes
grid.dirs = model.dirs
grid.rivers = model.rivers
grid.offset_x = offset_x
grid.offset_y = offset_y
grid.load_method = "full"
grid.conv_applied = false
collectgarbage()
end