Use biomegen.generate_all

by setting 'mapgen_rivers_distort = false' in minetest.conf

.gitignore

@@ -6,4 +6,7 @@ offset_x
 offset_y
 bounds_x
 bounds_y
+dirs
+rivers
 unused/
+data/

README.md

@@ -1,29 +1,36 @@
 mapgen_rivers
 =============
 
-Procedural map generator for Minetest 5.x. Still experimental and basic.
+Procedural map generator for Minetest 5.x. Focused on river networks, and features valley erosion and lakes.
 
 Contains two distinct programs: Python scripts for pre-processing, and Lua scripts to generate the map on Minetest.
 
-![Screenshot](https://user-images.githubusercontent.com/6905002/79073532-7a567f00-7ce7-11ea-9791-8fb453f5175d.png)
+![Screenshot](https://user-images.githubusercontent.com/6905002/79541028-687b3000-8089-11ea-9209-c23c15d75383.png)
 
 # Installation
 This mod should be placed in the `/mods` directory like any other Minetest mod.
 
 The Python part relies on external libraries that you need to install:
-- `numpy`, a widely used library for numerical calculations
+- `numpy` and `scipy`, widely used libraries for numerical calculations
 - `noise`, doing Perlin/Simplex noises
 - optionally, `matplotlib` (for map preview)
 
 They are commonly found on `pip` or `conda` Python distributions.
 
 # Usage
+By default, the mod contains a demo 400x400 map (so you can start the game directly), but it is recommended that you run the pre-processing script to generate a new map before world creation, if you can.
+
 ## Pre-processing
 Run the script `terrain_rivers.py` via command line. You can optionally append the map size (by default 400). Example for a 1000x1000 map:
 ```
 ./terrain_rivers.py 1000
 ```
-For a default 400x400 map, it should take between 1 and 2 minutes. It will generate 5 files directly in the mod folder, containing the map data (1.4 MB for the default size).
+For a default 400x400 map, it should take between 1 and 2 minutes. It will generate 5 files directly in the mod folder, containing the map data.
+
+If you have `matplotlib` installed, the script `view_map.py` can be used to get a map preview. Example:
+```
+./view_map.py data/
+```
 
 ## Map generation
 Just create a Minetest world with `singlenode` mapgen, enable this mod and start the world. The data files are immediately copied in the world folder so you can re-generate them afterwards, it won't affect the old worlds.

bounds.py

@@ -1,7 +1,10 @@
 import numpy as np
-import matplotlib.pyplot as plt
 
 def make_bounds(dirs, rivers):
+    """
+    Give an array of all horizontal and vertical bounds
+    """
+
     (Y, X) = dirs.shape
     bounds_h = np.zeros((Y, X-1), dtype='i4')
     bounds_v = np.zeros((Y-1, X), dtype='i4')
@@ -14,6 +17,10 @@ def make_bounds(dirs, rivers):
     return bounds_h, bounds_v
 
 def get_fixed(dirs):
+    """
+    Give the list of points that should not be twisted
+    """
+
     borders = np.zeros(dirs.shape, dtype='?')
     borders[-1,:] |= dirs[-1,:]==1
     borders[:,-1] |= dirs[:,-1]==2
@@ -28,6 +35,11 @@ def get_fixed(dirs):
     return borders | ~donors
 
 def twist(bounds_x, bounds_y, fixed, d=0.1, n=5):
+    """
+    Twist the grid (define an offset for every node). Model river bounds as if they were elastics.
+    Smoothes preferentially big rivers.
+    """
+
     moveable = ~fixed
 
     (Y, X) = fixed.shape
@@ -55,7 +67,7 @@ def twist(bounds_x, bounds_y, fixed, d=0.1, n=5):
 
         length = np.hypot(force_x, force_y)
         length[length==0] = 1
-        coeff = d / length * moveable
+        coeff = d / length * moveable # Normalize, take into account the direction only
         offset_x += force_x * coeff
         offset_y += force_y * coeff
 

demo_data/size

@@ -0,0 +1,2 @@
+401
+401

erosion.py

@@ -3,22 +3,33 @@ import scipy.ndimage as im
 import rivermapper as rm
 
 def advection(dem, dirs, rivers, time, K=1, m=0.5, sea_level=0):
+    """
+    Simulate erosion by rivers.
+    This models erosion as an upstream advection of elevations ("erosion waves").
+    Advection speed depends on water flux and parameters:
+
+    v = K * flux^m
+    """
+
     dirs = dirs.copy()
     dirs[0,:] = 0
     dirs[-1,:] = 0
     dirs[:,0] = 0
     dirs[:,-1] = 0
 
-    adv_time = 1 / (K*rivers**m)
+    adv_time = 1 / (K*rivers**m) # For every pixel, calculate the time an "erosion wave" will need to cross it.
     dem = np.maximum(dem, sea_level)
     dem_new = np.zeros(dem.shape)
 
     for y in range(dirs.shape[0]):
         for x in range(dirs.shape[1]):
+            # Elevations propagate upstream, so for every pixel we seek the downstream pixel whose erosion wave just reached the current pixel.
+            # This means summing the advection times downstream until we reach the erosion time.
             x0, y0 = x, y
             x1, y1 = x, y
             remaining = time
             while True:
+                # Move one pixel downstream
                 flow_dir = dirs[y0,x0]
                 if flow_dir == 0:
                     remaining = 0
@@ -32,19 +43,19 @@ def advection(dem, dirs, rivers, time, K=1, m=0.5, sea_level=0):
                 elif flow_dir == 4:
                     x1 -= 1
 
-                if remaining <= adv_time[y0,x0]:
+                if remaining <= adv_time[y0,x0]: # Time is over, we found it.
                     break
                 remaining -= adv_time[y0,x0]
                 x0, y0 = x1, y1
 
             c = remaining / adv_time[y0,x0]
-            dem_new[y,x] = c*dem[y1,x1] + (1-c)*dem[y0,x0]
+            dem_new[y,x] = c*dem[y1,x1] + (1-c)*dem[y0,x0] # If between 2 pixels, perform linear interpolation.
 
     return np.minimum(dem, dem_new)
 
 def diffusion(dem, time, d=1):
     radius = d * time**.5
-    return im.gaussian_filter(dem, radius, mode='reflect')
+    return im.gaussian_filter(dem, radius, mode='reflect') # Diffusive erosion is a simple Gaussian blur
 
 class EvolutionModel:
     def __init__(self, dem, K=1, m=0.5, d=1, sea_level=0, flow=False, flex_radius=100):
@@ -78,9 +89,9 @@ class EvolutionModel:
         self.flow_uptodate = False
 
     def define_isostasy(self):
-        self.ref_isostasy = im.gaussian_filter(self.dem, self.flex_radius, mode='reflect')
+        self.ref_isostasy = im.gaussian_filter(self.dem, self.flex_radius, mode='reflect') # Define a blurred version of the DEM that will be considered as the reference isostatic elevation.
 
     def adjust_isostasy(self, rate=1):
-        isostasy = im.gaussian_filter(self.dem, self.flex_radius, mode='reflect')
-        correction = (self.ref_isostasy - isostasy) * rate
-        self.dem = self.dem + correction
+        isostasy = im.gaussian_filter(self.dem, self.flex_radius, mode='reflect') # Calculate blurred DEM
+        correction = (self.ref_isostasy - isostasy) * rate # Compare it with the reference isostasy
+        self.dem = self.dem + correction # Adjust

geometry.lua

@@ -1,45 +1,37 @@
 local function distance_to_segment(x1, y1, x2, y2, x, y)
 	-- get the distance between point (x,y) and segment (x1,y1)-(x2,y2)
-	local a = (x1-x2)^2 + (y1-y2)^2
+	local a = (x1-x2)^2 + (y1-y2)^2 -- square of distance
 	local b = (x1-x)^2 + (y1-y)^2
 	local c = (x2-x)^2 + (y2-y)^2
 	if a + b < c then
+		-- The closest point of the segment is the extremity 1
 		return math.sqrt(b)
 	elseif a + c < b then
+		-- The closest point of the segment is the extremity 2
 		return math.sqrt(c)
 	else
+		-- The closest point is on the segment
 		return math.abs(x1 * (y2-y) + x2 * (y-y1) + x * (y1-y2)) / math.sqrt(a)
 	end
 end
 
 local function transform_quadri(X, Y, x, y)
-	-- X, Y 4-vectors giving the coordinates of the 4 nodes
+	-- To index points in an irregular quadrilateral, giving x and y between 0 (one edge) and 1 (opposite edge)
+	-- X, Y 4-vectors giving the coordinates of the 4 vertices
 	-- x, y position to index.
 	local x1, x2, x3, x4 = unpack(X)
 	local y1, y2, y3, y4 = unpack(Y)
 
+	-- Compare distance to 2 opposite edges, they give the X coordinate
 	local d23 = distance_to_segment(x2,y2,x3,y3,x,y)
 	local d41 = distance_to_segment(x4,y4,x1,y1,x,y)
 	local xc = d41 / (d23+d41)
 
+	-- Same for the 2 other edges, they give the Y coordinate
 	local d12 = distance_to_segment(x1,y1,x2,y2,x,y)
 	local d34 = distance_to_segment(x3,y3,x4,y4,x,y)
 	local yc = d12 / (d12+d34)
 	return xc, yc
 end
 
-local function area(X, Y) -- Signed area of polygon, in function of direction of rotation. Clockwise = positive.
-	local n = #X
-	local sum = X[1]*Y[n] - X[n]*Y[1]
-	for i=2, n do
-		sum = sum + X[i]*Y[i-1] - X[i-1]*Y[i]
-	end
-
-	return sum/2
-end
-
-return {
-	distance_to_segment = distance_to_segment,
-	transform_quadri = transform_quadri,
-	area = area,
-}
+return transform_quadri

heightmap.lua

@@ -0,0 +1,120 @@
+local modpath = minetest.get_modpath(minetest.get_current_modname()) .. '/'
+
+local make_polygons = dofile(modpath .. 'polygons.lua')
+local transform_quadri = dofile(modpath .. 'geometry.lua')
+
+local blocksize = mapgen_rivers.blocksize
+local sea_level = mapgen_rivers.sea_level
+local riverbed_slope = mapgen_rivers.riverbed_slope
+
+local MAP_BOTTOM = -31000
+
+-- Linear interpolation
+local function interp(v00, v01, v11, v10, xf, zf)
+	local v0 = v01*xf + v00*(1-xf)
+	local v1 = v11*xf + v10*(1-xf)
+	return v1*zf + v0*(1-zf)
+end
+
+local function heightmaps(minp, maxp)
+
+	local polygons = make_polygons(minp, maxp)
+	local incr = maxp.z-minp.z+1
+
+	local terrain_height_map = {}
+	local lake_height_map = {}
+
+	local i = 1
+	for z=minp.z, maxp.z do
+		for x=minp.x, maxp.x do
+			local poly = polygons[i]
+
+			if poly then
+				local xf, zf = transform_quadri(poly.x, poly.z, x/blocksize, z/blocksize)
+				local i00, i01, i11, i10 = unpack(poly.i)
+
+				-- Load river width on 4 edges and corners
+				local r_west, r_north, r_east, r_south = unpack(poly.rivers)
+				local c_NW, c_NE, c_SE, c_SW = unpack(poly.river_corners)
+
+				-- Calculate the depth factor for each edge and corner.
+				-- Depth factor:
+				-- < 0: outside river
+				-- = 0: on riverbank
+				-- > 0: inside river
+				local depth_factors = {
+					r_west - xf,
+					r_north - zf,
+					xf - r_east,
+					zf - r_south,
+					c_NW-xf-zf,
+					xf-zf-c_NE,
+					xf+zf-c_SE,
+					zf-xf-c_SW,
+				}
+
+				-- Find the maximal depth factor and determine to which river it belongs
+				local depth_factor_max = 0
+				local imax = 0
+				for i=1, 8 do
+					if depth_factors[i] >= depth_factor_max then
+						depth_factor_max = depth_factors[i]
+						imax = i
+					end
+				end
+
+				-- Transform the coordinates to have xf and zf = 0 or 1 in rivers (to avoid rivers having lateral slope and to accomodate the surrounding smoothly)
+				if imax == 0 then
+					local x0 = math.max(r_west, c_NW-zf, zf-c_SW)
+					local x1 = math.min(r_east, c_NE+zf, c_SE-zf)
+					local z0 = math.max(r_north, c_NW-xf, xf-c_NE)
+					local z1 = math.min(r_south, c_SW+xf, c_SE-xf)
+					xf = (xf-x0) / (x1-x0)
+					zf = (zf-z0) / (z1-z0)
+				elseif imax == 1 then
+					xf = 0
+				elseif imax == 2 then
+					zf = 0
+				elseif imax == 3 then
+					xf = 1
+				elseif imax == 4 then
+					zf = 1
+				elseif imax == 5 then
+					xf, zf = 0, 0
+				elseif imax == 6 then
+					xf, zf = 1, 0
+				elseif imax == 7 then
+					xf, zf = 1, 1
+				elseif imax == 8 then
+					xf, zf = 0, 1
+				end
+
+				-- Determine elevation by interpolation
+				local vdem = poly.dem
+				local terrain_height = math.floor(0.5+interp(
+					vdem[1],
+					vdem[2],
+					vdem[3],
+					vdem[4],
+					xf, zf
+				))
+
+				local lake_height = math.max(math.floor(poly.lake), terrain_height)
+				if imax > 0 and depth_factor_max > 0 then
+					terrain_height = math.min(math.max(lake_height, sea_level) - math.floor(1+depth_factor_max*riverbed_slope), terrain_height)
+				end
+
+				terrain_height_map[i] = terrain_height
+				lake_height_map[i] = lake_height
+			else
+				terrain_height_map[i] = MAP_BOTTOM
+				lake_height_map[i] = MAP_BOTTOM
+			end
+			i = i + 1
+		end
+	end
+
+	return terrain_height_map, lake_height_map
+end
+
+return heightmaps

init.lua

@@ -1,59 +1,26 @@
+mapgen_rivers = {}
+
 local modpath = minetest.get_modpath(minetest.get_current_modname()) .. '/'
-local worldpath = minetest.get_worldpath() .. '/'
-local load_map = dofile(modpath .. 'load.lua')
-local geometry = dofile(modpath .. 'geometry.lua')
 
-local function copy_if_needed(filename)
-	local wfilename = worldpath..filename
-	local wfile = io.open(wfilename, 'r')
-	if wfile then
-		wfile:close()
-		return
-	end
-	local mfilename = modpath..filename
-	local mfile = io.open(mfilename, 'r')
-	local wfile = io.open(wfilename, 'w')
-	wfile:write(mfile:read("*all"))
-	mfile:close()
-	wfile:close()
+dofile(modpath .. 'settings.lua')
+
+local blocksize = mapgen_rivers.blocksize
+local sea_level = mapgen_rivers.sea_level
+local riverbed_slope = mapgen_rivers.riverbed_slope
+local elevation_chill = mapgen_rivers.elevation_chill
+local use_distort = mapgen_rivers.distort
+local use_biomes = mapgen_rivers.biomes
+local use_biomegen_mod = use_biomes and minetest.global_exists('biomegen')
+use_biomes = use_biomes and not use_biomegen_mod
+
+if use_biomegen_mod then
+	biomegen.set_elevation_chill(elevation_chill)
 end
+dofile(modpath .. 'noises.lua')
 
-copy_if_needed('size')
-local sfile = io.open(worldpath..'size')
-local X = tonumber(sfile:read('*l'))
-local Z = tonumber(sfile:read('*l'))
-
-copy_if_needed('dem')
-local dem = load_map(worldpath..'dem', 2, true)
-copy_if_needed('lakes')
-local lakes = load_map(worldpath..'lakes', 2, true)
-copy_if_needed('bounds_x')
-local bounds_x = load_map(worldpath..'bounds_x', 4, false)
-copy_if_needed('bounds_y')
-local bounds_z = load_map(worldpath..'bounds_y', 4, false)
-
-copy_if_needed('offset_x')
-local offset_x = load_map(worldpath..'offset_x', 1, true)
-for k, v in ipairs(offset_x) do
-	offset_x[k] = (v+0.5)/256
-end
-
-copy_if_needed('offset_y')
-local offset_z = load_map(worldpath..'offset_y', 1, true)
-for k, v in ipairs(offset_z) do
-	offset_z[k] = (v+0.5)/256
-end
-
-
-local function index(x, z)
-	return z*X+x+1
-end
-
-local function get_point_location(x, z)
-	local i = index(x, z)
-	return x+offset_x[i], z+offset_z[i]
-end
+local heightmaps = dofile(modpath .. 'heightmap.lua')
 
+-- Linear interpolation
 local function interp(v00, v01, v11, v10, xf, zf)
 	local v0 = v01*xf + v00*(1-xf)
 	local v1 = v11*xf + v10*(1-xf)
@@ -62,216 +29,194 @@ end
 
 local data = {}
 
-local blocksize = 12
-local sea_level = 1
-local min_catchment = 25
-local max_catchment = 40000
-
-local storage = minetest.get_mod_storage()
-if storage:contains("blocksize") then
-	blocksize = storage:get_int("blocksize")
-else
-	storage:set_int("blocksize", blocksize)
-end
-if storage:contains("sea_level") then
-	sea_level = storage:get_int("sea_level")
-else
-	storage:set_int("sea_level", sea_level)
-end
-if storage:contains("min_catchment") then
-	min_catchment = storage:get_float("min_catchment")
-else
-	storage:set_float("min_catchment", min_catchment)
-end
-if storage:contains("max_catchment") then
-	max_catchment = storage:get_float("max_catchment")
-else
-	storage:set_float("max_catchment", max_catchment)
-end
-
--- Width coefficients: coefficients solving
---   wfactor * min_catchment ^ wpower = 1/(2*blocksize)
---   wfactor * max_catchment ^ wpower = 1
-local wpower = math.log(2*blocksize)/math.log(max_catchment/min_catchment)
-local wfactor = 1 / max_catchment ^ wpower
-local function river_width(flow)
-	flow = math.abs(flow)
-	if flow < min_catchment then
-		return 0
-	end
-
-	return math.min(wfactor * flow ^ wpower, 1)
-end
+local noise_x_obj, noise_z_obj, noise_distort_obj, noise_heat_obj, noise_heat_blend_obj
+local noise_x_map = {}
+local noise_z_map = {}
+local noise_distort_map = {}
+local noise_heat_map = {}
+local noise_heat_blend_map = {}
+local mapsize
+local init = false
 
 local function generate(minp, maxp, seed)
+	local chulens = {
+		x = maxp.x-minp.x+1,
+		y = maxp.y-minp.y+1,
+		z = maxp.z-minp.z+1,
+	}
+
+	if not init then
+		mapsize = {
+			x = chulens.x,
+			y = chulens.y+1,
+			z = chulens.z,
+		}
+		if use_distort then
+			noise_x_obj = minetest.get_perlin_map(mapgen_rivers.noise_params.distort_x, mapsize)
+			noise_z_obj = minetest.get_perlin_map(mapgen_rivers.noise_params.distort_z, mapsize)
+			noise_distort_obj = minetest.get_perlin_map(mapgen_rivers.noise_params.distort_amplitude, chulens)
+		end
+		if use_biomes then
+			noise_heat_obj = minetest.get_perlin_map(mapgen_rivers.noise_params.heat, chulens)
+			noise_heat_blend_obj = minetest.get_perlin_map(mapgen_rivers.noise_params.heat_blend, chulens)
+		end
+		init = true
+	end
+
+	local minp2d = {x=minp.x, y=minp.z}
+	if use_distort then
+		noise_x_obj:get_3d_map_flat(minp, noise_x_map)
+		noise_z_obj:get_3d_map_flat(minp, noise_z_map)
+		noise_distort_obj:get_2d_map_flat(minp2d, noise_distort_map)
+	end
+	if use_biomes then
+		noise_heat_obj:get_2d_map_flat(minp2d, noise_heat_map)
+		noise_heat_blend_obj:get_2d_map_flat(minp2d, noise_heat_blend_map)
+	end
+
+	local terrain_map, lake_map, incr, i_origin
+
+	if use_distort then
+		local xmin, xmax, zmin, zmax = minp.x, maxp.x, minp.z, maxp.z
+		local i = 0
+		local i2d = 0
+		for z=minp.z, maxp.z do
+			for y=minp.y, maxp.y+1 do
+				for x=minp.x, maxp.x do
+					i = i+1
+					i2d = i2d+1
+					local distort = noise_distort_map[i2d]
+					local xv = noise_x_map[i]*distort + x
+					if xv < xmin then xmin = xv end
+					if xv > xmax then xmax = xv end
+					noise_x_map[i] = xv
+					local zv = noise_z_map[i]*distort + z
+					if zv < zmin then zmin = zv end
+					if zv > zmax then zmax = zv end
+					noise_z_map[i] = zv
+				end
+				i2d = i2d-chulens.x
+			end
+		end
+
+		local pminp = {x=math.floor(xmin), z=math.floor(zmin)}
+		local pmaxp = {x=math.floor(xmax)+1, z=math.floor(zmax)+1}
+		incr = pmaxp.x-pminp.x+1
+		i_origin = 1 - pminp.z*incr - pminp.x
+		terrain_map, lake_map = heightmaps(pminp, pmaxp)
+	else
+		terrain_map, lake_map = heightmaps(minp, maxp)
+	end
+
 	local c_stone = minetest.get_content_id("default:stone")
 	local c_dirt = minetest.get_content_id("default:dirt")
 	local c_lawn = minetest.get_content_id("default:dirt_with_grass")
+	local c_dirtsnow = minetest.get_content_id("default:dirt_with_snow")
+	local c_snow = minetest.get_content_id("default:snowblock")
 	local c_sand = minetest.get_content_id("default:sand")
 	local c_water = minetest.get_content_id("default:water_source")
 	local c_rwater = minetest.get_content_id("default:river_water_source")
+	local c_ice = minetest.get_content_id("default:ice")
 
 	local vm, emin, emax = minetest.get_mapgen_object("voxelmanip")
 	vm:get_data(data)
 
 	local a = VoxelArea:new({MinEdge = emin, MaxEdge = emax})
 	local ystride = a.ystride -- Tip : the ystride of a VoxelArea is the number to add to the array index to get the index of the position above. It's faster because it avoids to completely recalculate the index.
-	local chulens = maxp.z - minp.z + 1
 
-	local polygons = {}
-	local xpmin, xpmax = math.max(math.floor(minp.x/blocksize - 0.5), 0), math.min(math.ceil(maxp.x/blocksize), X-2)
-	local zpmin, zpmax = math.max(math.floor(minp.z/blocksize - 0.5), 0), math.min(math.ceil(maxp.z/blocksize), Z-2)
+	local nid = mapsize.x*(mapsize.y-1) + 1
+	local incrY = -mapsize.x
+	local incrX = 1 - mapsize.y*incrY
+	local incrZ = mapsize.x*mapsize.y - mapsize.x*incrX - mapsize.x*mapsize.y*incrY
 
-	for xp = xpmin, xpmax do
-		for zp=zpmin, zpmax do
-			local iA = index(xp, zp)
-			local iB = index(xp+1, zp)
-			local iC = index(xp+1, zp+1)
-			local iD = index(xp, zp+1)
-			local poly_x = {offset_x[iA]+xp, offset_x[iB]+xp+1, offset_x[iC]+xp+1, offset_x[iD]+xp}
-			local poly_z = {offset_z[iA]+zp, offset_z[iB]+zp, offset_z[iC]+zp+1, offset_z[iD]+zp+1}
-			local polygon = {x=poly_x, z=poly_z, i={iA, iB, iC, iD}}
-
-			local bounds = {}
-			local xmin = math.max(math.floor(blocksize*math.min(unpack(poly_x)))+1, minp.x)
-			local xmax = math.min(math.floor(blocksize*math.max(unpack(poly_x))), maxp.x)
-			for x=xmin, xmax do
-				bounds[x] = {}
+	local i2d = 1
+	
+	for z = minp.z, maxp.z do
+		for x = minp.x, maxp.x do
+			local ivm = a:index(x, minp.y, z)
+			local ground_above = false
+			local temperature
+			if use_biomes then
+				temperature = noise_heat_map[i2d]+noise_heat_blend_map[i2d]
+			end
+			local terrain, lake
+			if not use_distort then
+				terrain = terrain_map[i2d]
+				lake = lake_map[i2d]
 			end
 
-			local i1 = 4
-			for i2=1, 4 do -- Loop on 4 edges
-				local x1, x2 = poly_x[i1], poly_x[i2]
-				local lxmin = math.floor(blocksize*math.min(x1, x2))+1
-				local lxmax = math.floor(blocksize*math.max(x1, x2))
-				if lxmin <= lxmax then
-					local z1, z2 = poly_z[i1], poly_z[i2]
-					local a = (z1-z2) / (x1-x2)
-					local b = blocksize*(z1 - a*x1)
-					for x=math.max(lxmin, minp.x), math.min(lxmax, maxp.x) do
-						table.insert(bounds[x], a*x+b)
-					end
-				end
-				i1 = i2
-			end
-			for x=xmin, xmax do
-				local xlist = bounds[x]
-				table.sort(xlist)
-				local c = math.floor(#xlist/2)
-				for l=1, c do
-					local zmin = math.max(math.floor(xlist[l*2-1])+1, minp.z)
-					local zmax = math.min(math.floor(xlist[l*2]), maxp.z)
-					local i = (x-minp.x) * chulens + (zmin-minp.z) + 1
-					for z=zmin, zmax do
-						polygons[i] = polygon
-						i = i + 1
-					end
-				end
-			end
+			for y = maxp.y+1, minp.y, -1 do
+				if use_distort then
+					local xn = noise_x_map[nid]
+					local zn = noise_z_map[nid]
+					local x0 = math.floor(xn)
+					local z0 = math.floor(zn)
 
-			polygon.dem = {dem[iA], dem[iB], dem[iC], dem[iD]}
-			polygon.lake = math.min(lakes[iA], lakes[iB], lakes[iC], lakes[iD])
+					local i0 = i_origin + z0*incr + x0
+					local i1 = i0+1
+					local i2 = i1+incr
+					local i3 = i2-1
 
-			local river_west = river_width(bounds_z[iA])
-			local river_north = river_width(bounds_x[iA-zp])
-			local river_east = 1-river_width(bounds_z[iB])
-			local river_south = 1-river_width(bounds_x[iD-zp-1])
-			if river_west > river_east then
-				local mean = (river_west + river_east) / 2
-				river_west = mean
-				river_east = mean
-			end
-			if river_north > river_south then
-				local mean = (river_north + river_south) / 2
-				river_north = mean
-				river_south = mean
-			end
-			polygon.rivers = {river_west, river_north, river_east, river_south}
-		end
-	end
-
-	local i = 1
-	for x = minp.x, maxp.x do
-		for z = minp.z, maxp.z do
-			local poly = polygons[i]
-			if poly then
-				local xf, zf = geometry.transform_quadri(poly.x, poly.z, x/blocksize, z/blocksize)
-				local i00, i01, i11, i10 = unpack(poly.i)
-
-				local is_river = false
-				local r_west, r_north, r_east, r_south = unpack(poly.rivers)
-				if xf >= r_east then
-					is_river = true
-					xf = 1
-				elseif xf <= r_west then
-					is_river = true
-					xf = 0
-				end
-				if zf >= r_south then
-					is_river = true
-					zf = 1
-				elseif zf <= r_north then
-					is_river = true
-					zf = 0
+					terrain = interp(terrain_map[i0], terrain_map[i1], terrain_map[i2], terrain_map[i3], xn-x0, zn-z0)
+					lake = math.min(lake_map[i0], lake_map[i1], lake_map[i2], lake_map[i3])
 				end
 
-				if not is_river then
-					xf = (xf-r_west) / (r_east-r_west)
-					zf = (zf-r_north) / (r_south-r_north)
-				end
+				if y <= maxp.y then
 
-				local vdem = poly.dem
-				local terrain_height = math.floor(0.5+interp(
-					vdem[1],
-					vdem[2],
-					vdem[3],
-					vdem[4],
-					xf, zf
-				))
-
-				local lake_height = math.floor(poly.lake)
-
-				local is_lake = lake_height > terrain_height
-				
-				local ivm = a:index(x, minp.y-1, z)
-
-				if terrain_height >= minp.y then
-					for y=minp.y, math.min(maxp.y, terrain_height) do
-						if y == terrain_height then
-							if is_lake or y <= sea_level then
-								data[ivm] = c_sand
-							elseif is_river then
-								data[ivm] = c_rwater
-							else
-								data[ivm] = c_lawn
-							end
-						else
+					local is_lake = lake > terrain
+					local ivm = a:index(x, y, z)
+					if y <= terrain then
+						if not use_biomes or y <= terrain-1 or ground_above then
 							data[ivm] = c_stone
+						elseif is_lake or y < sea_level then
+							data[ivm] = c_sand
+						else
+							local temperature_y = temperature - y*elevation_chill
+							if temperature_y >= 15 then
+								data[ivm] = c_lawn
+							elseif temperature_y >= 0 then
+								data[ivm] = c_dirtsnow
+							else
+								data[ivm] = c_snow
+							end
 						end
-						ivm = ivm + ystride
+					elseif y <= lake and lake > sea_level then
+						if not use_biomes or temperature - y*elevation_chill >= 0 then
+							data[ivm] = c_rwater
+						else
+							data[ivm] = c_ice
+						end
+					elseif y <= sea_level then
+						data[ivm] = c_water
 					end
 				end
 
-				if lake_height > sea_level then
-					if is_lake and lake_height > minp.y then
-						for y=math.max(minp.y, terrain_height+1), math.min(maxp.y, lake_height) do
-							data[ivm] = c_rwater
-							ivm = ivm + ystride
-						end
-					end
-				else
-					for y=math.max(minp.y, terrain_height+1), math.min(maxp.y, sea_level) do
-						data[ivm] = c_water
-						ivm = ivm + ystride
-					end
+				ground_above = y <= terrain
+
+				ivm = ivm + ystride
+				if use_distort then
+					nid = nid + incrY
 				end
 			end
-			i = i + 1
+
+			if use_distort then
+				nid = nid + incrX
+			end
+			i2d = i2d + 1
+		end
+
+		if use_distort then
+			nid = nid + incrZ
 		end
 	end
 
-	vm:set_data(data)
-	minetest.generate_ores(vm, minp, maxp)
+	if use_biomegen_mod then
+		biomegen.generate_all(data, a, vm, minp, maxp, seed)
+	else
+		vm:set_data(data)
+		mietest.generate_ores(vm, minp, maxp)
+	end
+
 	vm:set_lighting({day = 0, night = 0})
 	vm:calc_lighting()
 	vm:update_liquids()

load.lua

@@ -1,11 +1,14 @@
-local function load_map(filename, bytes, signed)
-	local file = io.open(filename, 'r')
+local worldpath = minetest.get_worldpath() .. "/river_data/"
+
+local function load_map(filename, bytes, signed, size)
+	local file = io.open(worldpath .. filename, 'r')
 	local data = file:read('*all')
+	if #data < bytes*size then
+		data = minetest.decompress(data)
+	end
 
 	local map = {}
 
-	local size = math.floor(#data/bytes)
-
 	for i=1, size do
 		local i0, i1 = (i-1)*bytes+1, i*bytes
 		local elements = {data:byte(i0, i1)}

mod.conf

@@ -0,0 +1,4 @@
+name = mapgen_rivers
+title = Map generator with realistic rivers
+depends = default
+optional_depends = biomegen

noises.lua

@@ -0,0 +1,37 @@
+mapgen_rivers.noise_params = {
+	distort_x = {
+		offset = 0,
+		scale = 1,
+		seed = -4574,
+		spread = {x=64, y=32, z=64},
+		octaves = 3,
+		persistence = 0.75,
+		lacunarity = 2,
+	},
+
+	distort_z = {
+		offset = 0,
+		scale = 1,
+		seed = -7940,
+		spread = {x=64, y=32, z=64},
+		octaves = 3,
+		persistence = 0.75,
+		lacunarity = 2,
+	},
+
+	distort_amplitude = {
+		offset = 0,
+		scale = 10,
+		seed = 676,
+		spread = {x=1024, y=1024, z=1024},
+		octaves = 5,
+		persistence = 0.5,
+		lacunarity = 2,
+		flags = "absvalue",
+	},
+
+	heat = minetest.get_mapgen_setting_noiseparams('mg_biome_np_heat'),
+	heat_blend = minetest.get_mapgen_setting_noiseparams('mg_biome_np_heat_blend'),
+}
+
+mapgen_rivers.noise_params.heat.offset = mapgen_rivers.noise_params.heat.offset + mapgen_rivers.sea_level*mapgen_rivers.elevation_chill

polygons.lua

@@ -0,0 +1,205 @@
+local modpath = minetest.get_modpath(minetest.get_current_modname()) .. '/'
+local mod_data_path = modpath .. 'data/'
+if not io.open(mod_data_path .. 'size', 'r') then
+	mod_data_path = modpath .. 'demo_data/'
+end
+
+local world_data_path = minetest.get_worldpath() .. '/river_data/'
+minetest.mkdir(world_data_path)
+
+local load_map = dofile(modpath .. 'load.lua')
+
+local function copy_if_needed(filename)
+	local wfilename = world_data_path..filename
+	local wfile = io.open(wfilename, 'r')
+	if wfile then
+		wfile:close()
+		return
+	end
+	local mfilename = mod_data_path..filename
+	local mfile = io.open(mfilename, 'r')
+	local wfile = io.open(wfilename, 'w')
+	wfile:write(mfile:read("*all"))
+	mfile:close()
+	wfile:close()
+end
+
+copy_if_needed('size')
+local sfile = io.open(world_data_path..'size')
+local X = tonumber(sfile:read('*l'))
+local Z = tonumber(sfile:read('*l'))
+sfile:close()
+
+copy_if_needed('dem')
+local dem = load_map('dem', 2, true, X*Z)
+copy_if_needed('lakes')
+local lakes = load_map('lakes', 2, true, X*Z)
+copy_if_needed('dirs')
+local dirs = load_map('dirs', 1, false, X*Z)
+copy_if_needed('rivers')
+local rivers = load_map('rivers', 4, false, X*Z)
+
+copy_if_needed('offset_x')
+local offset_x = load_map('offset_x', 1, true, X*Z)
+for k, v in ipairs(offset_x) do
+	offset_x[k] = (v+0.5)/256
+end
+
+copy_if_needed('offset_y')
+local offset_z = load_map('offset_y', 1, true, X*Z)
+for k, v in ipairs(offset_z) do
+	offset_z[k] = (v+0.5)/256
+end
+
+-- To index a flat array representing a 2D map
+local function index(x, z)
+	return z*X+x+1
+end
+
+local blocksize = mapgen_rivers.blocksize
+local min_catchment = mapgen_rivers.min_catchment
+local max_catchment = mapgen_rivers.max_catchment
+
+-- Width coefficients: coefficients solving
+--   wfactor * min_catchment ^ wpower = 1/(2*blocksize)
+--   wfactor * max_catchment ^ wpower = 1
+local wpower = math.log(2*blocksize)/math.log(max_catchment/min_catchment)
+local wfactor = 1 / max_catchment ^ wpower
+local function river_width(flow)
+	flow = math.abs(flow)
+	if flow < min_catchment then
+		return 0
+	end
+
+	return math.min(wfactor * flow ^ wpower, 1)
+end
+
+local noise_heat -- Need a large-scale noise here so no heat blend
+local elevation_chill = mapgen_rivers.elevation_chill
+local function get_temperature(x, y, z)
+	local pos = {x=x, y=z}
+	return noise_heat:get2d(pos) - y*elevation_chill
+end
+
+local glaciers = mapgen_rivers.glaciers
+local glacier_factor = mapgen_rivers.glacier_factor
+
+local init = false
+
+-- On map generation, determine into which polygon every point (in 2D) will fall.
+-- Also store polygon-specific data
+local function make_polygons(minp, maxp)
+	if not init then
+		if glaciers then
+			noise_heat = minetest.get_perlin(mapgen_rivers.noise_params.heat)
+		end
+		init = true
+	end
+
+	local chulens = maxp.x - minp.x + 1
+
+	local polygons = {}
+	-- Determine the minimum and maximum coordinates of the polygons that could be on the chunk, knowing that they have an average size of 'blocksize' and a maximal offset of 0.5 blocksize.
+	local xpmin, xpmax = math.max(math.floor(minp.x/blocksize - 0.5), 0), math.min(math.ceil(maxp.x/blocksize), X-2)
+	local zpmin, zpmax = math.max(math.floor(minp.z/blocksize - 0.5), 0), math.min(math.ceil(maxp.z/blocksize), Z-2)
+
+	-- Iterate over the polygons
+	for xp = xpmin, xpmax do
+		for zp=zpmin, zpmax do
+			local iA = index(xp, zp)
+			local iB = index(xp+1, zp)
+			local iC = index(xp+1, zp+1)
+			local iD = index(xp, zp+1)
+			-- Extract the vertices of the polygon
+			local poly_x = {offset_x[iA]+xp, offset_x[iB]+xp+1, offset_x[iC]+xp+1, offset_x[iD]+xp}
+			local poly_z = {offset_z[iA]+zp, offset_z[iB]+zp, offset_z[iC]+zp+1, offset_z[iD]+zp+1}
+			local polygon = {x=poly_x, z=poly_z, i={iA, iB, iC, iD}}
+
+			local bounds = {} -- Will be a list of the intercepts of polygon edges for every Z position (scanline algorithm)
+			-- Calculate the min and max Z positions 
+			local zmin = math.max(math.floor(blocksize*math.min(unpack(poly_z)))+1, minp.z)
+			local zmax = math.min(math.floor(blocksize*math.max(unpack(poly_z))), maxp.z)
+			-- And initialize the arrays
+			for z=zmin, zmax do
+				bounds[z] = {}
+			end
+
+			local i1 = 4
+			for i2=1, 4 do -- Loop on 4 edges
+				local z1, z2 = poly_z[i1], poly_z[i2]
+				-- Calculate the integer Z positions over which this edge spans
+				local lzmin = math.floor(blocksize*math.min(z1, z2))+1
+				local lzmax = math.floor(blocksize*math.max(z1, z2))
+				if lzmin <= lzmax then -- If there is at least one position in it
+					local x1, x2 = poly_x[i1], poly_x[i2]
+					-- Calculate coefficient of the equation defining the edge: X=aZ+b
+					local a = (x1-x2) / (z1-z2)
+					local b = blocksize*(x1 - a*z1)
+					for z=math.max(lzmin, minp.z), math.min(lzmax, maxp.z) do
+						-- For every Z position involved, add the intercepted X position in the table
+						table.insert(bounds[z], a*z+b)
+					end
+				end
+				i1 = i2
+			end
+			for z=zmin, zmax do
+				-- Now sort the bounds list
+				local zlist = bounds[z]
+				table.sort(zlist)
+				local c = math.floor(#zlist/2)
+				for l=1, c do
+					-- Take pairs of X coordinates: all positions between them belong to the polygon.
+					local xmin = math.max(math.floor(zlist[l*2-1])+1, minp.x)
+					local xmax = math.min(math.floor(zlist[l*2]), maxp.x)
+					local i = (z-minp.z) * chulens + (xmin-minp.x) + 1
+					for x=xmin, xmax do
+						-- Fill the map at these places
+						polygons[i] = polygon
+						i = i + 1
+					end
+				end
+			end
+
+			local poly_dem = {dem[iA], dem[iB], dem[iC], dem[iD]}
+			polygon.dem = poly_dem
+			polygon.lake = math.min(lakes[iA], lakes[iB], lakes[iC], lakes[iD])
+
+			-- Now, rivers.
+			-- Load river flux values for the 4 corners
+			local riverA = river_width(rivers[iA])
+			local riverB = river_width(rivers[iB])
+			local riverC = river_width(rivers[iC])
+			local riverD = river_width(rivers[iD])
+			if glaciers then -- Widen the river
+				if get_temperature(poly_x[1]*blocksize, poly_dem[1], poly_z[1]*blocksize) < 0 then
+					riverA = math.min(riverA*glacier_factor, 1)
+				end
+				if get_temperature(poly_x[2]*blocksize, poly_dem[2], poly_z[2]*blocksize) < 0 then
+					riverB = math.min(riverB*glacier_factor, 1)
+				end
+				if get_temperature(poly_x[3]*blocksize, poly_dem[3], poly_z[3]*blocksize) < 0 then
+					riverC = math.min(riverC*glacier_factor, 1)
+				end
+				if get_temperature(poly_x[4]*blocksize, poly_dem[4], poly_z[4]*blocksize) < 0 then
+					riverD = math.min(riverD*glacier_factor, 1)
+				end
+			end
+
+			polygon.river_corners = {riverA, 1-riverB, 2-riverC, 1-riverD}
+
+			-- Flow directions
+			local dirA, dirB, dirC, dirD = dirs[iA], dirs[iB], dirs[iC], dirs[iD]
+			-- Determine the river flux on the edges, by testing dirs values
+			local river_west = (dirA==1 and riverA or 0) + (dirD==3 and riverD or 0)
+			local river_north = (dirA==2 and riverA or 0) + (dirB==4 and riverB or 0)
+			local river_east = 1 - (dirB==1 and riverB or 0) - (dirC==3 and riverC or 0)
+			local river_south = 1 - (dirD==2 and riverD or 0) - (dirC==4 and riverC or 0)
+
+			polygon.rivers = {river_west, river_north, river_east, river_south}
+		end
+	end
+
+	return polygons
+end
+
+return make_polygons

rivermapper.py

@@ -19,9 +19,14 @@ neighbours_dirs = np.array([
 neighbours_pattern = neighbours_dirs > 0
 
 def flow_dirs_lakes(dem, random=0):
+    """
+    Calculates flow direction in D4 (4 choices) for every pixel of the DEM
+    Also returns an array of lake elevation
+    """
+
     (Y, X) = dem.shape
 
-    dem_margin = np.zeros((Y+2, X+2))
+    dem_margin = np.zeros((Y+2, X+2)) # We need a margin of one pixel at every edge, to prevent crashes when scanning the neighbour pixels on the borders
     dem_margin[1:-1,1:-1] = dem
     if random > 0:
         dem_margin += np.random.random(dem_margin.shape) * random
@@ -41,10 +46,11 @@ def flow_dirs_lakes(dem, random=0):
         dem_east = dem_margin[y,X]
         borders.append((dem_east, dem_east, y, X))
 
+    # Make a binary heap
     heapq.heapify(borders)
 
     dirs = np.zeros((Y+2, X+2), dtype='u1')
-    dirs[-2:,:] = 1
+    dirs[-2:,:] = 1 # Border pixels flow outside the map
     dirs[:,-2:] = 2
     dirs[ :2,:] = 3
     dirs[:, :2] = 4
@@ -56,21 +62,26 @@ def flow_dirs_lakes(dem, random=0):
         heapq.heappush(borders, (alt, altmax, y, x))
 
     while len(borders) > 0:
-        (alt, altmax, y, x) = heapq.heappop(borders)
+        (alt, altmax, y, x) = heapq.heappop(borders) # Take the lowest pixel in the queue
         neighbours = dirs[y-1:y+2, x-1:x+2]
-        empty_neighbours = (neighbours == 0) * neighbours_pattern
-        neighbours += empty_neighbours * neighbours_dirs
+        empty_neighbours = (neighbours == 0) * neighbours_pattern # Find the neighbours whose flow direction is not yet defined
+        neighbours += empty_neighbours * neighbours_dirs # They flow into the pixel being studied
 
-        lake = max(alt, altmax)
+        lake = max(alt, altmax) # Set lake elevation to the maximal height of the downstream section.
         lakes[y-1,x-1] = lake
 
         coords = np.transpose(empty_neighbours.nonzero())
-        for (dy,dx) in coords-1:
+        for (dy,dx) in coords-1: # Add these neighbours into the queue
             add_point(y+dy, x+dx, lake)
 
     return dirs[1:-1,1:-1], lakes
 
 def accumulate(dirs, dem=None):
+    """
+    Calculates the quantity of water that accumulates at every pixel,
+    following flow directions.
+    """
+
     (Y, X) = dirs.shape
     dirs_margin = np.zeros((Y+2,X+2))-1
     dirs_margin[1:-1,1:-1] = dirs
@@ -79,13 +90,13 @@ def accumulate(dirs, dem=None):
     def calculate_quantity(y, x):
         if quantity[y,x] > 0:
             return quantity[y,x]
-        q = 1
+        q = 1 # Consider that every pixel contains a water quantity of 1 by default.
         neighbours = dirs_margin[y:y+3, x:x+3]
-        donors = neighbours == neighbours_dirs
+        donors = neighbours == neighbours_dirs # Identify neighbours that give their water to the pixel being studied
 
         coords = np.transpose(donors.nonzero())
         for (dy,dx) in coords-1:
-            q += calculate_quantity(y+dy, x+dx)
+            q += calculate_quantity(y+dy, x+dx) # Add water quantity of the donors pixels (this triggers calculation for these pixels, recursively)
         quantity[y, x] = q
         return q
 
@@ -96,5 +107,9 @@ def accumulate(dirs, dem=None):
     return quantity
 
 def flow(dem):
+    """
+    Calculates flow directions and water quantity
+    """
+
     dirs, lakes = flow_dirs_lakes(dem)
     return dirs, lakes, accumulate(dirs, dem)

save.py

@@ -1,8 +1,13 @@
 import numpy as np
+import zlib
 
 def save(data, fname, dtype=None):
     if dtype is not None:
         data = data.astype(dtype)
 
+    bin_data = data.tobytes()
+    bin_data_comp = zlib.compress(bin_data, 9)
+    if len(bin_data_comp) < len(bin_data):
+        bin_data = bin_data_comp
     with open(fname, 'wb') as f:
-        f.write(data.tobytes())
+        f.write(bin_data)

settings.lua

@@ -0,0 +1,54 @@
+local storage = minetest.get_mod_storage()
+local settings = minetest.settings
+
+local function get_settings(key, dtype, default)
+	if storage:contains(key) then
+		if dtype == "string" then
+			return storage:get_string(key)
+		elseif dtype == "int" then
+			return storage:get_int(key)
+		elseif dtype == "float" then
+			return storage:get_float(key)
+		elseif dtype == "bool" then
+			return storage:get_string(key) == 'true'
+		end
+	end
+
+	local conf_val = settings:get('mapgen_rivers_' .. key)
+	if conf_val then
+		if dtype == "int" then
+			conf_val = tonumber(conf_val)
+			storage:set_int(key, conf_val)
+		elseif dtype == "float" then
+			conf_val = tonumber(conf_val)
+			storage:set_float(key, conf_val)
+		elseif dtype == "string" or dtype == "bool" then
+			storage:set_string(key, conf_val)
+		end
+
+		return conf_val
+	else
+		if dtype == "int" then
+			storage:set_int(key, default)
+		elseif dtype == "float" then
+			storage:set_float(key, default)
+		elseif dtype == "string" then
+			storage:set_string(key, default)
+		elseif dtype == "bool" then
+			storage:set_string(key, tostring(default))
+		end
+
+		return default
+	end
+end
+
+mapgen_rivers.blocksize = get_settings('blocksize', 'int', 12)
+mapgen_rivers.sea_level = get_settings('sea_level', 'int', 1)
+mapgen_rivers.min_catchment = get_settings('min_catchment', 'float', 25)
+mapgen_rivers.max_catchment = get_settings('max_catchment', 'float', 40000)
+mapgen_rivers.riverbed_slope = get_settings('riverbed_slope', 'float', 0.4) * mapgen_rivers.blocksize
+mapgen_rivers.distort = get_settings('distort', 'bool', true)
+mapgen_rivers.biomes = get_settings('biomes', 'bool', true)
+mapgen_rivers.glaciers = get_settings('glaciers', 'bool', true)
+mapgen_rivers.glacier_factor = get_settings('glacier_factor', 'float', 8)
+mapgen_rivers.elevation_chill = get_settings('elevation_chill', 'float', 0.25)

settings.py

@@ -0,0 +1,11 @@
+def read_config_file(fname):
+    settings = {}
+
+    with open(fname, 'r') as f:
+        for line in f:
+            slist = line.split('=', 1)
+            if len(slist) >= 2:
+                prefix, suffix = slist
+                settings[prefix.strip()] = suffix.strip()
+
+    return settings

terrain_default.conf

@@ -0,0 +1,14 @@
+mapsize = 1000
+scale = 400
+vscale = 300
+offset = 0
+persistence = 0.6
+lacunarity = 2.0
+
+K = 1
+m = 0.35
+d = 0.8
+sea_level = 0
+
+time = 10
+niter = 10

terrain_rivers.py

@@ -7,110 +7,110 @@ from erosion import EvolutionModel
 import bounds
 import os
 import sys
+import settings
 
 # Always place in this script's parent directory
 os.chdir(os.path.dirname(sys.argv[0]))
 argc = len(sys.argv)
 
+params = {}
+
 if argc > 1:
-	mapsize = int(sys.argv[1])
-else:
-	mapsize = 400
+	if os.path.isfile(sys.argv[1]):
+		params = settings.read_config_file(sys.argv[1])
+	else:
+		mapsize = int(sys.argv[1])
 
-scale = mapsize / 2
-n = np.zeros((mapsize, mapsize))
+def get_setting(name, default):
+	if name in params:
+		return params[name]
+	return default
 
-#micronoise_depth = 0.05
+mapsize = int(get_setting('mapsize', 400))
+scale = float(get_setting('scale', 200.0))
+vscale = float(get_setting('vscale', 200.0))
+offset = float(get_setting('offset', 0.0))
+persistence = float(get_setting('persistence', 0.5))
+lacunarity = float(get_setting('lacunarity', 2.0))
 
+K = float(get_setting('K', 1.0))
+m = float(get_setting('m', 0.35))
+d = float(get_setting('d', 1.0))
+sea_level = float(get_setting('sea_level', 0.0))
+flex_radius = float(get_setting('flex_radius', 20.0))
+
+time = float(get_setting('time', 10.0))
+niter = int(get_setting('niter', 10))
+
+n = np.zeros((mapsize+1, mapsize+1))
+
+# Set noise parameters
 params = {
-    "octaves" : int(np.log2(mapsize)),
-    "persistence" : 0.5,
-    "lacunarity" : 2.,
+    "octaves" : int(np.ceil(np.log2(mapsize)))+1,
+    "persistence" : persistence,
+    "lacunarity" : lacunarity,
 }
 
+# Determine noise offset randomly
 xbase = np.random.randint(65536)
 ybase = np.random.randint(65536)
 
-for x in range(mapsize):
-    for y in range(mapsize):
+# Generate the noise
+for x in range(mapsize+1):
+    for y in range(mapsize+1):
         n[x,y] = noise.snoise2(x/scale + xbase, y/scale + ybase, **params)
 
-#micronoise = np.random.rand(mapsize, mapsize)
-#nn = np.exp(n*2) + micronoise*micronoise_depth
-nn = n*mapsize/5 + mapsize/20
+nn = n*vscale + offset
 
+# Initialize landscape evolution model
 print('Initializing model')
-model = EvolutionModel(nn, K=1, m=0.35, d=1, sea_level=0)
+model = EvolutionModel(nn, K=1, m=0.35, d=1, sea_level=0, flex_radius=flex_radius)
 
-print('Flow calculation 1')
+dt = time/niter
+
+# Run the model's processes: the order in which the processes are run is arbitrary and could be changed.
+print('Initial flow calculation')
 model.calculate_flow()
 
-print('Advection 1')
-model.advection(2)
-
-print('Isostatic equilibration 1')
-model.adjust_isostasy()
-
-print('Flow calculation 2')
-model.calculate_flow()
-
-print('Diffusion')
-model.diffusion(4)
-
-print('Advection 2')
-model.advection(2)
-
-print('Isostatic equilibration 2')
-model.adjust_isostasy()
-
-print('Flow calculation 3')
-model.calculate_flow()
+for i in range(niter):
+    print('Iteration {:d} of {:d}'.format(i+1, niter))
+    print('Diffusion')
+    model.diffusion(dt)
+    print('Advection')
+    model.advection(dt)
+    print('Isostatic equilibration')
+    model.adjust_isostasy()
+    print('Flow calculation')
+    model.calculate_flow()
 
 print('Done')
 
+# Twist the grid
 bx, by = bounds.make_bounds(model.dirs, model.rivers)
-ox, oy = bounds.twist(bx, by, bounds.get_fixed(model.dirs))
+offset_x, offset_y = bounds.twist(bx, by, bounds.get_fixed(model.dirs))
 
-offset_x = np.clip(np.floor(ox * 256), -128, 127)
-offset_y = np.clip(np.floor(oy * 256), -128, 127)
+# Convert offset in 8-bits
+offset_x = np.clip(np.floor(offset_x * 256), -128, 127)
+offset_y = np.clip(np.floor(offset_y * 256), -128, 127)
 
+if not os.path.isdir('data'):
+    os.mkdir('data')
+os.chdir('data')
+# Save the files
 save(model.dem, 'dem', dtype='>i2')
 save(model.lakes, 'lakes', dtype='>i2')
-save(np.abs(bx), 'bounds_x', dtype='>i4')
-save(np.abs(by), 'bounds_y', dtype='>i4')
 save(offset_x, 'offset_x', dtype='i1')
 save(offset_y, 'offset_y', dtype='i1')
 
+save(model.dirs, 'dirs', dtype='u1')
+save(model.rivers, 'rivers', dtype='>u4')
+
 with open('size', 'w') as sfile:
-    sfile.write('{:d}\n{:d}'.format(mapsize, mapsize))
+    sfile.write('{:d}\n{:d}'.format(mapsize+1, mapsize+1))
 
+# Display the map if matplotlib is found
 try:
-    import matplotlib.pyplot as plt
-
-    plt.subplot(2,2,1)
-    plt.pcolormesh(nn, cmap='viridis')
-    plt.gca().set_aspect('equal', 'box')
-    #plt.colorbar(orientation='horizontal')
-    plt.title('Raw elevation')
-
-    plt.subplot(2,2,2)
-    plt.pcolormesh(model.lakes, cmap='viridis')
-    plt.gca().set_aspect('equal', 'box')
-    #plt.colorbar(orientation='horizontal')
-    plt.title('Lake surface elevation')
-
-    plt.subplot(2,2,3)
-    plt.pcolormesh(model.dem, cmap='viridis')
-    plt.gca().set_aspect('equal', 'box')
-    #plt.colorbar(orientation='horizontal')
-    plt.title('Elevation after advection')
-
-    plt.subplot(2,2,4)
-    plt.pcolormesh(model.rivers, vmin=0, vmax=mapsize**2/25, cmap='Blues')
-    plt.gca().set_aspect('equal', 'box')
-    #plt.colorbar(orientation='horizontal')
-    plt.title('Rivers discharge')
-
-    plt.show()
+    from view_map import view_map
+    view_map(model.dem, model.lakes, model.rivers)
 except:
     pass

view_map.py

@@ -1,30 +1,52 @@
 #!/usr/bin/env python3
 
 import numpy as np
+import zlib
+import matplotlib.colors as mcol
 import matplotlib.pyplot as plt
 
-shape = np.loadtxt('size', dtype='u4')
-n = shape[0] * shape[1]
-dem = np.fromfile('dem', dtype='>i2').reshape(shape)
-lakes = np.fromfile('lakes', dtype='>i2').reshape(shape)
-rivers = np.fromfile('rivers', dtype='>u4').reshape(shape)
+def view_map(dem, lakes, rivers, scale):
+    plt.subplot(1,3,1)
+    plt.pcolormesh(np.arange(dem.shape[0]+1)*scale, np.arange(dem.shape[1]+1)*scale, dem, cmap='viridis')
+    plt.gca().set_aspect('equal', 'box')
+    plt.colorbar(orientation='horizontal')
+    plt.title('Raw elevation')
 
-plt.subplot(1,3,1)
-plt.pcolormesh(dem, cmap='viridis')
-plt.gca().set_aspect('equal', 'box')
-#plt.colorbar(orientation='horizontal')
-plt.title('Raw elevation')
+    plt.subplot(1,3,2)
+    plt.pcolormesh(np.arange(lakes.shape[0]+1)*scale, np.arange(lakes.shape[1]+1)*scale, lakes, cmap='viridis')
+    plt.gca().set_aspect('equal', 'box')
+    plt.colorbar(orientation='horizontal')
+    plt.title('Lake surface elevation')
 
-plt.subplot(1,3,2)
-plt.pcolormesh(lakes, cmap='viridis')
-plt.gca().set_aspect('equal', 'box')
-#plt.colorbar(orientation='horizontal')
-plt.title('Lake surface elevation')
+    plt.subplot(1,3,3)
+    plt.pcolormesh(np.arange(rivers.shape[0]+1)*scale, np.arange(rivers.shape[1]+1)*scale, rivers, cmap='Blues', norm=mcol.LogNorm())
+    plt.gca().set_aspect('equal', 'box')
+    plt.colorbar(orientation='horizontal')
+    plt.title('Rivers flux')
 
-plt.subplot(1,3,3)
-plt.pcolormesh(np.log(rivers), vmin=0, vmax=np.log(n/25), cmap='Blues')
-plt.gca().set_aspect('equal', 'box')
-#plt.colorbar(orientation='horizontal')
-plt.title('Rivers discharge')
+    plt.show()
 
-plt.show()
+if __name__ == "__main__":
+    import sys
+    import os
+
+    scale = 1
+    if len(sys.argv) > 1:
+        os.chdir(sys.argv[1])
+    if len(sys.argv) > 2:
+        scale = int(sys.argv[2])
+
+    def load_map(name, dtype, shape):
+        dtype = np.dtype(dtype)
+        with open(name, 'rb') as f:
+            data = f.read()
+        if len(data) < shape[0]*shape[1]*dtype.itemsize:
+            data = zlib.decompress(data)
+        return np.frombuffer(data, dtype=dtype).reshape(shape)
+
+    shape = np.loadtxt('size', dtype='u4')
+    dem = load_map('dem', '>i2', shape)
+    lakes = load_map('lakes', '>i2', shape)
+    rivers = load_map('rivers', '>u4', shape)
+
+    view_map(dem, lakes, rivers, scale)