import sys, Image, random

levels = 8
if len(sys.argv) > 1:
    levels = int(sys.argv[1])

seed = 1
if len(sys.argv) > 2:
    seed = int(sys.argv[2])
random.seed(seed)

def makeHeightField(level):
	size = 2**level + 1
	h = [[0]*size for _ in range(0,size)]
	displacement = 4.0
	for l in range(level-1, -1, -1):
		step = 2**l
		for i in range(0, size, step*2):
			for j in range(step, size, step*2):
				h[i][j] = (h[i][j-step]+h[i][j+step])/2.0 + random.gauss(0,displacement)
		for i in range(step, size, step*2):
			for j in range(0, size, step*2):
				h[i][j] = (h[i-step][j]+h[i+step][j])/2.0 + random.gauss(0,displacement)
		for i in range(step, size, step*2):
			for j in range(step, size, step*2):
				h[i][j] = (h[i-step][j]+h[i+step][j]+h[i][j-step]+h[i][j+step])/4.0 + random.gauss(0,displacement)
		displacement /= 1.8
	return h


hf = makeHeightField(levels)

maxHeight = max(map(max,hf))
minHeight = min(map(min,hf))
if minHeight == maxHeight: scale = 1
else: scale = 255/(maxHeight-minHeight)

img = Image.new('L', (len(hf), len(hf[0])))
for j in range(0, len(hf)):
    for i in range(0, len(hf[j])):
        img.putpixel((i,j), (hf[i][j]-minHeight)*scale)

img.save('heightfield.png')