151 lines
3.8 KiB
Lua
151 lines
3.8 KiB
Lua
-- Generate the grid using terrainlib_lua
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-- Only called on first mapgen, if there is no grid yet
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-- Constants
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local EvolutionModel = dofile(mapgen_rivers.modpath .. '/terrainlib_lua/erosion.lua')
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local twist = dofile(mapgen_rivers.modpath .. '/terrainlib_lua/twist.lua')
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local blocksize = mapgen_rivers.settings.blocksize
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local tectonic_speed = mapgen_rivers.settings.tectonic_speed
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local np_base = table.copy(mapgen_rivers.noise_params.base)
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np_base.spread = vector.divide(np_base.spread, blocksize)
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local evol_params = mapgen_rivers.settings.evol_params
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local time = mapgen_rivers.settings.evol_time
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local time_step = mapgen_rivers.settings.evol_time_step
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local niter = math.ceil(time/time_step)
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time_step = time / niter
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local use_margin = mapgen_rivers.settings.margin
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local margin_width = mapgen_rivers.settings.margin_width / blocksize
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local margin_elev = mapgen_rivers.settings.margin_elev
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local X = math.floor(mapgen_rivers.settings.map_x_size / blocksize)
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local Y = math.floor(mapgen_rivers.settings.map_z_size / blocksize)
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local function margin(dem, width, elev)
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local X, Y = dem.X, dem.Y
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for i=1, width do
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local c1 = ((i-1)/width) ^ 0.5
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local c2 = (1-c1) * elev
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local index = (i-1)*X + 1
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for x=1, X do
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dem[index] = dem[index] * c1 + c2
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index = index + 1
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end
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index = i
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for y=1, Y do
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dem[index] = dem[index] * c1 + c2
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index = index + X
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end
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index = X*(Y-i) + 1
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for x=1, X do
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dem[index] = dem[index] * c1 + c2
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index = index + 1
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end
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index = X-i + 1
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for y=1, Y do
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dem[index] = dem[index] * c1 + c2
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index = index + X
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end
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end
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end
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-- Generate grid
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minetest.log("action", '[mapgen_rivers] Generating grid, this may take a while...')
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if X*Y > 4e6 then
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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.")
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end
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local seed = tonumber(minetest.get_mapgen_setting("seed"):sub(-10))
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np_base.seed = (np_base.seed or 0) + seed
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local nobj_base = PerlinNoiseMap(np_base, {x=X, y=1, z=Y})
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local dem = nobj_base:get_3d_map_flat({x=0, y=0, z=0})
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dem.X = X
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dem.Y = Y
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if use_margin then
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margin(dem, margin_width, margin_elev)
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end
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local model = EvolutionModel(evol_params)
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model.dem = dem
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local ref_dem = model:define_isostasy(dem)
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local tectonic_step = tectonic_speed * time_step
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collectgarbage()
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for i=1, niter do
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minetest.log("info", "[mapgen_rivers] Iteration " .. i .. " of " .. niter)
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model:diffuse(time_step)
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model:flow()
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model:erode(time_step)
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if i < niter then
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if tectonic_step ~= 0 then
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nobj_base:get_3d_map_flat({x=0, y=tectonic_step*i, z=0}, ref_dem)
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if use_margin then
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margin(ref_dem, margin_width, margin_elev)
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end
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end
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model:isostasy()
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end
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collectgarbage()
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end
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model:flow()
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local mfloor = math.floor
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local mmin, mmax = math.min, math.max
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local unpk, schar = unpack, string.char
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local offset_x, offset_y = twist(model.dirs, model.rivers, 5)
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for i=1, X*Y do
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offset_x[i] = mmin(mmax(offset_x[i]*256, -128), 127)
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offset_y[i] = mmin(mmax(offset_y[i]*256, -128), 127)
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end
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-- Write data
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local datapath = mapgen_rivers.world_data_path
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minetest.mkdir(datapath)
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local sfile = io.open(datapath .. 'size', "w")
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sfile:write(X..'\n'..Y)
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sfile:close()
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local function write_file(filename, data, bytes)
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local file = io.open(datapath .. filename, 'wb')
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local bytelist = {}
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for j=1, bytes do
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bytelist[j] = 0
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end
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for i=1, #data do
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local n = mfloor(data[i])
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data[i] = n
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for j=bytes, 2, -1 do
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bytelist[j] = n % 256
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n = mfloor(n / 256)
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end
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bytelist[1] = n % 256
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file:write(schar(unpk(bytelist)))
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end
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file:close()
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end
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write_file('dem', model.dem, 2)
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write_file('lakes', model.lakes, 2)
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write_file('dirs', model.dirs, 1)
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write_file('rivers', model.rivers, 4)
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write_file('offset_x', offset_x, 1)
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write_file('offset_y', offset_y, 1)
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