genmap.py

from itertools import product
import random

from noise import snoise2
from PIL import Image
import numpy as np


size = (500, 500)
shape = (size[1], size[0])

im = Image.new('RGB', size)

terrain = np.zeros(shape, dtype='uint8')
mountains = np.zeros(shape, dtype='uint8')
forest = np.zeros(shape, dtype='uint8')


terrain_kw = dict(
    octaves=10,
    persistence=0.6,
    repeatx=1000 + (random.random() * 100 - 50),
    repeaty=1001 + (random.random() * 100 - 50),
    base=0.0,
)
mountain_kw = dict(
    octaves=10,
    persistence=0.6,
    repeatx=999 + (random.random() * 100 - 50),
    repeaty=1002 + (random.random() * 100 - 50),
    base=0.0,
)
forest_kw = dict(
    octaves=10,
    persistence=0.6,
    repeatx=998 + (random.random() * 100 - 50),
    repeaty=1003 + (random.random() * 100 - 50),
    base=0.0,
)

mountain_th = 0.4
forest_th_lo = 0.2
forest_th_hi = mountain_th + 0.1

stretch_factor = 3
zoom = 16.0 * 32
for y, x in product(*(range(n) for n in size)):
    terrain_z = snoise2(
        x/zoom,
        y/zoom,
        **terrain_kw
    )
    terrain_z = min(1.0, max(-1.0, terrain_z * 2))

    mountain_z = snoise2(
        x/zoom,
        y/zoom,
        **mountain_kw
    )

    forest_z = snoise2(
        x/zoom,
        y/zoom,
        **forest_kw
    )

    if terrain_z >= 0:
        terrain[x,y] = 255

    if terrain_z >= mountain_th and mountain_z >= 0.0:
        mountains[x,y] = 255

    if (forest_th_lo <= terrain_z <= forest_th_hi) and forest_z >= 0.0:
        forest[x,y] = 255


def l_to_rgb(im, f):
    w, h = im.shape
    ret = np.empty((w, h, 3), dtype=np.uint8)
    ret[:, :, 0] = im * f[0]
    ret[:, :, 1] = im * f[1]
    ret[:, :, 2] = im * f[2]
    return ret

terrain_rgb = l_to_rgb(terrain, (0, 1, 0))
mountains_rgb = l_to_rgb(mountains, (0.5, 0.5, 0.5))
forest_rgb = l_to_rgb(forest, (0, 0.5, 0))

im.frombytes(terrain_rgb)
im = im.convert('RGB')

im2 = Image.new('RGB', size)
im2.frombytes(mountains_rgb)

im3 = Image.new('RGB', size)
im3.frombytes(forest_rgb)

mask2 = Image.new('L', size)
mask2.frombytes(mountains)

mask3 = Image.new('L', size)
mask3.frombytes(forest)


im.paste(im2, (0, 0), mask2)
im.paste(im3, (0, 0), mask3)

im.show()