2d raycaster that runs in your terminal!

terminal_raycaster2d.py

from collections import defaultdict
import os
import time
import numpy as np
from pynput import keyboard
from pynput.keyboard import Key


TERMX, TERMY = os.get_terminal_size()

def center(*lines):
    for line in lines:
        yield line.center(TERMX)


class RayCaster:
    keys = defaultdict(bool)
    directions = ((Key.up, (-1, 0)),
                  (Key.right, (0, 1)),
                  (Key.down, (1, 0)),
                  (Key.left, (0, -1)))
    running = True

    def __init__(self, DIM, pos=(10,10)):
        self.DIM = DIM
        self.grid = np.pad(np.full(DIM, 1, dtype=int), pad_width=1,
                           mode='constant', constant_values=2)
        for _ in range(40):
            self.grid[np.random.randint(DIM[1]), np.random.randint(DIM[0])] = 2

        self.pos = np.array(pos)
        self.listener = keyboard.Listener(on_press=self.pressed)
        self.listener.start()

    def pressed(self, key):
        self.keys[key] = True

    def grid_rays(self, angle):
        angle = np.array([np.cos(angle), np.sin(angle)])
        with np.errstate(divide="ignore"):
            delta = abs(1/angle)
        step = 2 * np.heaviside(angle, 1) - 1
        side_dis = ((step + 1) / 2) * delta
        map_pos = self.pos.copy()

        while True:
            side = 0 if side_dis[0] < side_dis[1] else 1
            side_dis[side] += delta[side]
            map_pos[side] += step[side]
            self.revealed[tuple(map_pos)] = self.grid[tuple(map_pos)]
            if self.grid[tuple(map_pos)] == 2:
                break

    def print_revealed(self):
        print(*center(*(" ".join(" .W@"[value] for value in row)
                        for row in self.revealed)), sep="\n")

    def start(self):
        while self.running:
            self.revealed = np.zeros_like(self.grid)

            # Cast rays
            for theta in np.linspace(0, 2*np.pi, 100, endpoint=False):
                self.grid_rays(theta)

            self.revealed[tuple(self.pos)] = 3
            os.system("clear")
            self.print_revealed()
            time.sleep(.2)

            # Input handling
            for key, direction in self.directions:
                if (self.keys[key] and
                    all(1 <= pos + dir_ <= dim for pos, dir_, dim in zip(self.pos, direction, self.DIM))):
                    self.pos += direction
                    self.keys[key] = False
            if self.keys[Key.esc]:
                self.running = False

        self.listener.stop()


if __name__=="__main__":
    RayCaster((40, 40)).start()