#!/usr/bin/env python3

"""A basic cellular automata cave generation example using SciPy.

http://www.roguebasin.com/index.php?title=Cellular_Automata_Method_for_Generating_Random_Cave-Like_Levels

This will print the result to the console, so be sure to run this from the

command line.

"""

import scipy.signal # type: ignore

import numpy as np # type: ignore

def convolve(tiles: np.array, wall_rule: int = 5) -> np.array:

"""Return the next step of the cave generation algorithm.

`tiles` is the input array. (0: wall, 1: floor)

If the 3x3 area around a tile (including itself) has `wall_rule` number of

walls then the tile will become a wall.

"""

# Use convolve2d, the 2nd input is a 3x3 ones array.

neighbors = scipy.signal.convolve2d(

~tiles, [[1, 1, 1], [1, 1, 1], [1, 1, 1]], "same"

)

return neighbors < wall_rule # Apply the wall rule.

def show(tiles: np.array) -> None:

"""Print out the tiles of an array."""

for line in tiles:

print("".join("# "[int(cell)] for cell in line))

if __name__ == "__main__":

WIDTH, HEIGHT = 60, 20

INITIAL_CHANCE = 0.45 # Initial wall chance.

CONVOLVE_STEPS = 4

# 0: wall, 1: floor

tiles = np.random.random((HEIGHT, WIDTH)) > INITIAL_CHANCE

for _ in range(CONVOLVE_STEPS):

tiles = convolve(tiles)

tiles[[0, -1], :] = 0 # Ensure surrounding wall.

tiles[:, [0, -1]] = 0

show(tiles)