python and libtcod: generating terrain using perlin noise

Question

I found a great post about world generation, which can be found here.

It does a good job describing what needs to be done, but I'm having trouble figuring out how to do it in python. I believe it was done in as3, but I'm not sure for certain. Any way, I also found a libtcod function for perlin noise:

noise2d=libtcod.noise_new(2)
value = libtcod.noise_turbulence_perlin(noise2d,[0.5,0.7],32.0)

I don't really know how to implement this, and then assign characters based on the height.

If someone could help me translate the steps from the article to python, I'd really appreciate it. Thanks

Answer 1

Here's a class I wrote some years ago that creates a world map for my roguelike prototype DomeriaRL. The relevant part is in the __generate method.

It applies noise to a heightmap, normalizes it, and creates the tiles based on the values of the heightmap.

I'm using a color map to create smooth transitions from one tile kind to another.

from constants.constant import *
from world import World
from worldtile import WorldTile

class WorldGenerator(object):
  """Randomly generates a new world with terrain and objects"""

  def regular(self):
    """Randomly generate a new world with some water, swamps, hills, some objects etc"""

    idx = [ 0 , 15, 75, 90, 101 ] # indexes of the keys 
    col = [ T.Color(0,100,100),
            T.Color(0,75,0), 
            T.Color(50,150,0), 
            T.Color(150,120,80), 
            T.Color(180,180,180)]

    map=T.color_gen_map(col,idx)

    tiles = zip(idx, [[SWAMP, PLAINS],
                      [PLAINS, FOREST], 
                      [HILLS, FOREST],
                      [HILLS, HILLS, MOUNTAINS],
                      [HILLS, MOUNTAINS,MOUNTAINS]])

    world = self.__generate(map, tiles)
    return world

  def __generate(self, colormap, mtiles, noise_zoom=1, noise_octaves=10):
    hm = T.heightmap_new(WORLD_WIDTH, WORLD_HEIGHT)
    hm1 = T.heightmap_new(WORLD_WIDTH, WORLD_HEIGHT)
    hm2 = T.heightmap_new(WORLD_WIDTH, WORLD_HEIGHT)

    noise = T.noise_new(2)
    T.heightmap_add_fbm(hm1, noise, noise_zoom, noise_zoom, 0.0, 0.0, noise_octaves, 0.0, 1.0)
    T.heightmap_add_fbm(hm2, noise, noise_zoom*2, noise_zoom*2, 0.0, 0.0, noise_octaves/2, 0.0, 1.0)

    T.heightmap_multiply_hm(hm1, hm2, hm)
    T.heightmap_normalize(hm, mi=0.0, ma=1)

    tiles = {}

    # 0...100 -> value from noised heightmap
    for x in xrange(0, 101):
      lower = [c for c in mtiles if c[0] <= x][-1] # tile is between lower and upper color
      upper = [c for c in mtiles if c[0] > x][0]

      # calculating percentage
      lower_c = x - lower[0]
      upper_c = upper[0] - x
      count = lower_c + upper_c

      tiles[x] = colormap[x], lower[1], int(upper_c * 1.0 / count * 100), upper[1] 

    # generate world grid
    grid = []
    for x in xrange(WORLD_WIDTH):
      grid.append([])
      for y in xrange(WORLD_HEIGHT):
        hm_v = T.heightmap_get_value(hm, x, y)
        grid[x].append(WorldTile(*tiles[int(hm_v * 100)]))

    T.heightmap_delete(hm)
    T.heightmap_delete(hm1)
    T.heightmap_delete(hm2)

    objects = []
    while len(objects) < 5:
      for x in xrange(WORLD_WIDTH):
        for y in xrange(WORLD_HEIGHT):
          r = random.randrange(0, 10000)
          pos = [wo for wo in WORLDOBJECTS if wo.chance >= r and grid[x][y].tile in wo.tiles]
          if pos:
            o = random.choice(pos).create(x, y)
            objects.append(o)

    return World(grid, objects)

An example world map looks like this:

Note that this game uses libtcod 1.5.1b1, and some function names changed in newer releases.