mapgen.py

import sys
import random
import bisect
import pygame as pg


MAP_SIZE = (30, 15)
TILE_SIZE = (32, 32)

TEXTURES = ["w", "d", "g", "c"]

TEXTURE_DICT = {
    "w" : pg.Color("skyblue"),
    "d" : pg.Color("sandybrown"),
    "g" : pg.Color("lightgreen"),
    "c" : pg.Color("slategray")
}

ADJACENT_CHANCE = {
    ("w","w") : (("w",0.8), ("d",0.0), ("g", 0.2), ("c",0.0)),
    ("w","d") : (("w",0.0), ("d",0.0), ("g", 1), ("c",0.0)),
    ("w","g") : (("w",0.5), ("d",0.0), ("g", 0.5), ("c",0.0)),
    ("w","c") : (("w",0.0), ("d",1), ("g", 0.0), ("c",0.0)),
    ("d","d") : (("w",0.0), ("d",0.6), ("g", 0.35), ("c",0.05)),
    ("d","g") : (("w",0.0), ("d",0.45), ("g", 0.525), ("c",0.025)),
    ("d","c") : (("w",0.0), ("d",1), ("g", 0.0), ("c",0.0)),
    ("g","g") : (("w",0.15), ("d",0.15), ("g", 0.70), ("c",0.0)),
    ("g","c") : (("w",0.0), ("d",1), ("g", 0.0), ("c",0.0)),
    ("c","c") : (("w",0.0), ("d",1), ("g", 0.0), ("c",0.0))
}


def make_map(size):
    nodes = {}
    for j in range(size[1]):
        for i in range(size[0]):
            up = nodes.get((i,j-1), random.choice(TEXTURES))
            prev = nodes.get((i-1,j), random.choice(TEXTURES))
            choice = CHANCE_DICT.get((up,prev)) or CHANCE_DICT.get((prev,up))
            nodes[i,j] = choice()
    return nodes


def draw_tile(surface, coords, texture):
    x, y = coords
    color = TEXTURE_DICT[texture]
    rect = ((x*TILE_SIZE[0], y*TILE_SIZE[1]), TILE_SIZE)
    surface.fill(color, rect)
    

def weighted_chooser(items):
    """
    Returns a function that makes a weighted random choice from items.
    Stolen from SO.
    """
    added_weights = []
    last_sum = 0
    for item, weight in items:
        last_sum += weight
        added_weights.append(last_sum)
    def choice():
        roll = random.random() * last_sum
        return items[bisect.bisect(added_weights, roll)][0]
    return choice


def main():
    global CHANCE_DICT
    CHANCE_DICT = {k:weighted_chooser(v) for k,v in ADJACENT_CHANCE.items()}
    pg.init()
    screen_size = MAP_SIZE[0]*TILE_SIZE[0], MAP_SIZE[1]*TILE_SIZE[1], 
    screen = pg.display.set_mode(screen_size)
    tiles = make_map(MAP_SIZE)
    for coords,texture in tiles.items():
        draw_tile(screen, coords, texture)
    pg.display.update()
    while pg.event.wait().type != pg.QUIT:
        pass
    pg.quit()
    sys.exit()


if __name__ == "__main__":
    main()