Initial commit: working example using a basis of Simplex noise and implementing river flowing, lakes, and erosion

terrain_rivers.py

@@ -0,0 +1,101 @@
+#!/usr/bin/env python3
+
+import numpy as np
+import noise
+from save import save
+from erosion import EvolutionModel
+import os
+import sys
+
+# Always place in this script's parent directory
+os.chdir(os.path.dirname(sys.argv[0]))
+argc = len(sys.argv)
+
+if argc > 1:
+	mapsize = int(sys.argv[1])
+else:
+	mapsize = 400
+
+scale = mapsize / 2
+n = np.zeros((mapsize, mapsize))
+
+#micronoise_depth = 0.05
+
+params = {
+    "octaves" : 8,
+    "persistence" : 0.5,
+    "lacunarity" : 2.,
+}
+
+xbase = np.random.randint(65536)
+ybase = np.random.randint(65536)
+
+for x in range(mapsize):
+    for y in range(mapsize):
+        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
+
+print('Initializing model')
+model = EvolutionModel(nn, K=1, m=0.35, d=1, sea_level=0)
+
+print('Flow calculation 1')
+model.calculate_flow()
+
+print('Advection 1')
+model.advection(2)
+
+print('Flow calculation 2')
+model.calculate_flow()
+
+print('Diffusion')
+model.diffusion(4)
+
+print('Advection 2')
+model.advection(2)
+
+print('Flow calculation 3')
+model.calculate_flow()
+
+print('Done')
+
+save(model.dem, 'dem', dtype='>i2')
+save(model.lakes, 'lakes', dtype='>i2')
+save(model.dirs, 'links', dtype='u1')
+save(model.rivers, 'rivers', dtype='>u4')
+
+with open('size', 'w') as sfile:
+    sfile.write('{:d}\n{:d}'.format(mapsize, mapsize))
+
+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()
+except:
+    pass