roads.py

from opensimplex import OpenSimplex
from PIL import Image
import random
from heapq import *

mtns = OpenSimplex(seed = random.getrandbits(32))
hills = OpenSimplex(seed = random.getrandbits(32))
bumps = OpenSimplex(seed = random.getrandbits(32))

def terrain((x,y)):
	return mtns.noise2d(x/30.0, y/30.0)*1/4 + hills.noise2d(x/5.0,y/5.0)*1/2 + bumps.noise2d(x, y)*1/4

dirs = [(dx,dy) for dx in [0, -1, 1] for dy in [0, -1, 1]][1:]

def Astar(city1, city2):
	heap = [(abs(city1[0]-city2[0])+abs(city1[1]-city2[1]), 0, [city1])] #A heap of (estimate, parLn, parRd)
	visited = set()
	while True:
		(_, parLn, parRd) = heappop(heap)
		point = parRd[0]
		if point == city2: return parRd
		for (dx, dy) in dirs:
			newPoint = (point[0] + dx, point[1] + dy)
			if newPoint in visited: continue
			visited.add(newPoint)
			d = (dx**2 + dy**2)**0.5
			slope = (terrain(point) - terrain(newPoint))/d
			newParRd = [newPoint] + parRd
			newParLn = parLn + (1 + (10**10 * slope**8)) * d
			newEstimate = newParLn + abs(newPoint[0] - city2[0]) + abs(newPoint[1] - city2[1])
			heappush(heap, (newEstimate, newParLn, newParRd))

def main():
	road = Astar((32,100), (100,32))
	im = Image.new("RGB", (128,128))
	pixels = []
	for x in range(128):
		for y in range(128):
			if (x,y) in [(32,100), (100,32)]:
				pixels.append((0,0,256))
			elif (x,y) in road:
				pixels.append((0,0,0))
			else:
				pixels.append((256, 256, 256))

	im.putdata(pixels)
	im.save("roads.bmp")