Factor out level into a separate file.

Now the terrain.py file can be reused for making more levels.

maps/tank_strike.py

@@ -0,0 +1,26 @@
+#!/usr/bin/env python3
+#
+# Player must fly over the mountains and destroy two tank convoys.
+
+from terrain import *
+
+left_barrier()
+terrain(500)
+oxen_field()
+airfield()
+terrain(200, rockiness=0.05)
+mountain(end_y=50)
+mountain(height=90, width=150, end_y=30)
+new_territory()
+mountain(height=140, width=120, end_y=40)
+terrain(300, rockiness=0.1)
+convoy()
+airfield(owner="PLAYER2", right_side=True)
+terrain(500, rockiness=0.3)
+convoy(max_tanks=5)
+terrain(500, rockiness=0.1)
+right_barrier()
+new_territory()
+
+write_to_file("tank_strike.sop")
+

maps/terrain.py

@@ -193,22 +193,3 @@ def write_to_file(filename):
 		print_ground(file)
 		print("}", file=file)
 
-left_barrier()
-terrain(500)
-oxen_field()
-airfield()
-terrain(200, rockiness=0.05)
-mountain(end_y=50)
-mountain(height=90, width=150, end_y=30)
-new_territory()
-mountain(height=140, width=120, end_y=40)
-terrain(300, rockiness=0.1)
-convoy()
-airfield(owner="PLAYER2", right_side=True)
-terrain(500, rockiness=0.3)
-terrain(500, rockiness=0.1)
-right_barrier()
-new_territory()
-
-write_to_file("tank_strike.sop")
-