langtons_ant

__author__ = 'travisl'

# This is an implementation of Langton's ant, written in Python using SFML
# Wikipedia article: http://en.wikipedia.org/wiki/Langton%27s_ant

import sfml as sf

UP = 0
RIGHT = 1
DOWN = 2
LEFT = 3

# Window / tile sizes
SIZE = 4
WIDTH = 300
HEIGHT = 300


class Langton:
    def __init__(self):
        self.win = sf.RenderWindow(sf.VideoMode(WIDTH, HEIGHT), "Langton's Ant")
        self.win.display()
        self.paused = False
        self.finished = False
        self.is_running = True
        self.step = False
        self.win.show()
        self.ant_x = (WIDTH//SIZE)//2
        self.ant_y = (HEIGHT//SIZE)//2
        self.ant_dir = RIGHT

        self.ant_rekt = sf.RectangleShape()
        self.ant_rekt.position = ((SIZE * self.ant_x) + 1, (SIZE * self.ant_y) + 1)
        self.ant_rekt.size = (SIZE/2, SIZE/2)
        self.ant_rekt.fill_color = sf.Color.RED

        # create grid
        self.tiles = []
        for y in range(HEIGHT//SIZE):
            row = []
            for x in range(WIDTH//SIZE):
                rekt = sf.RectangleShape()
                rekt.position = (SIZE * x, SIZE * y)
                rekt.size = (SIZE, SIZE)
                rekt.fill_color = sf.Color.WHITE
                row.append(rekt)
            self.tiles.append(row)

    def run(self):
        while self.is_running:
            self.handle_events()
            if not self.paused and not self.finished:
                self.update()
            elif self.step:
                self.step = False
                self.update()
            self.draw()

        self.win.close()

    def update(self):
        rekt = self.tiles[self.ant_y][self.ant_x]
        is_white = rekt.fill_color == sf.Color.WHITE
        rekt.fill_color = sf.Color.BLACK if is_white else sf.Color.WHITE

        # turn right on white, left on black, then move forward one unit
        if self.ant_dir == UP:
            self.ant_dir = RIGHT if is_white else LEFT
        elif self.ant_dir == RIGHT:
            self.ant_dir = DOWN if is_white else UP
        elif self.ant_dir == DOWN:
            self.ant_dir = LEFT if is_white else RIGHT
        elif self.ant_dir == LEFT:
            self.ant_dir = UP if is_white else DOWN

        # move ant
        if self.ant_dir == UP:
            self.ant_y -= 1
        elif self.ant_dir == RIGHT:
            self.ant_x += 1
        elif self.ant_dir == DOWN:
            self.ant_y += 1
        elif self.ant_dir == LEFT:
            self.ant_x -= 1

        self.ant_rekt.position = ((SIZE * self.ant_x) + 1, (SIZE * self.ant_y) + 1)

        if self.ant_x < 0 or self.ant_x >= WIDTH//SIZE or self.ant_y < 0 or self.ant_y >= HEIGHT//SIZE:
            self.finished = True

    def handle_events(self):
        for event in self.win.events:
            if type(event) is sf.CloseEvent:
                self.is_running = False
            if type(event) is sf.KeyEvent and event.pressed:
                if event.code == sf.Keyboard.ESCAPE:
                    self.is_running = False
                if event.code == sf.Keyboard.SPACE:
                    self.paused = not self.paused
                if event.code == sf.Keyboard.RIGHT and self.paused:
                    self.step = True

    def draw(self):
        self.win.clear(sf.Color.WHITE)
        # draw board
        for y in range(HEIGHT//SIZE):
            for x in range(WIDTH//SIZE):
                tile = self.tiles[y][x]
                self.win.draw(tile)

        self.win.draw(self.ant_rekt)
        self.win.display()

if __name__ == '__main__':
    l = Langton()
    l.run()