# Langton’s Ant

This program is a simulation of Langton’s Ant. The following image shows the ant on its highway.

#### Controls

• F1 takes a screenshot
• Space stops and resumes the ant’s movement

``````# Python 2.7.7 Code
# Pygame 1.9.1 (for Python 2.7.7)
# Jonathan Frech 27th of October, 2015
#         edited 29th of October, 2015``````

``````# importing needed modules
import pygame, sys, time, math, os, random, datetime

""" CLASSES """
# dummy class for global variables
class dummy():
pass

""" FUNCTIONS """
# validates a color integer
def colorValid(_color, _min = 0, _max = 255):
newColor = math.fabs(_color)
n = _max - _min
if newColor > n:
if int(newColor / n) % 2 == 0:
newColor = newColor % n
else:
newColor = n - (newColor % n)

return int(newColor) + _min

# gets the position on a circle with a position, radius and an angle
return [
]

# returns an integer version of given positon
def intpos(_pos):
return [int(_pos[0]), int(_pos[1])]

# basic vector functions
def vecConvert(p1, p2):
return [p2[0] - p1[0], p2[1] - p1[1]]
def vecLen(vec):
return math.sqrt( (vec[0]**2) + (vec[1]**2) )
def vecMultiply(vec, n):
return [vec[0] * n, vec[1] * n]
def vecGetPoint(vec, point):
return [point[0] + vec[0], point[1] + vec[1]]
return [vec1[0] + vec2[0], vec1[1] + vec2[1]]

# saves the current surface
def savesurf():
try:
if not os.path.isdir(main.SAVEPATH):
os.mkdir(main.SAVEPATH)

name = "img" + str(len(os.listdir(main.SAVEPATH))) + ".png"
pygame.image.save( pygame.transform.scale(main.SURF, main.SCREENSIZE) , main.SAVEPATH + name)
except:
pass

# quits the program
def quit():
sys.exit()

""" TICK; RENDER """
# tick function
def tick():
# handle events
for event in pygame.event.get():
if event.type == pygame.QUIT:
quit()

if event.type == pygame.KEYDOWN:
if event.key == pygame.K_SPACE:
main.RUNNING = not main.RUNNING

if event.key == pygame.K_F1:
savesurf()

for _ in range(0, 10):
#if main.TICKS % 60 == 0:
if not main.FINISHED and main.RUNNING:
if main.ANTSURF.get_at(main.ANTPOS) == (0, 0, 0, 255):
main.ANTDIR = (main.ANTDIR+1) % 4
main.ANTSURF.set_at(main.ANTPOS, [255, 255, 255])
else:
main.ANTDIR = (main.ANTDIR-1) % 4
main.ANTSURF.set_at(main.ANTPOS, [0, 0, 0])

if main.ANTDIR == 0:
main.ANTPOS[1] += 1
elif main.ANTDIR == 1:
main.ANTPOS[0] -= 1
elif main.ANTDIR == 2:
main.ANTPOS[1] -= 1
elif main.ANTDIR == 3:
main.ANTPOS[0] += 1

main.STEPS += 1
pygame.display.set_caption(main.CAPTION + " (" + str(main.STEPS) + " steps)")

if main.ANTPOS[0] < 0 or main.ANTPOS[0] >= main.WIDTH or main.ANTPOS[1] < 0 or main.ANTPOS[1] >= main.HEIGHT:
main.FINISHED = True

# render function
def render():
# blit
main.SURF.blit(main.ANTSURF, [0, 0])
main.SURF.set_at(main.ANTPOS, [255, 0, 0])

main.SCREEN.blit(pygame.transform.scale(main.SURF, main.SCREENSIZE), [0, 0])

#flip
pygame.display.flip()

""" INIT """
# initialize program
def init():
main.WIDTH, main.HEIGHT = 108, 72
main.SIZE = [main.WIDTH, main.HEIGHT]
main.SURF = pygame.Surface(main.SIZE)

main.SCREENSIZE = [1080, 720]
main.SCREEN = pygame.display.set_mode(main.SCREENSIZE)

main.CAPTION = "Langton's Ant"
main.TICKS = 0
main.SAVEPATH = os.getcwd() + "/out/"

main.ANTSURF = pygame.Surface(main.SIZE)
main.ANTPOS = [main.WIDTH/2, main.HEIGHT/2]
main.ANTDIR = 0
main.FINISHED = False
main.RUNNING = True
main.STEPS = 0

# functions
pygame.display.set_caption(main.CAPTION)

""" RUN """
# run function (uses tick() and render())
def run():
ticksPerSecond = 60
lastTime = time.time() * 1000000000
nsPerTick =  1000000000.0 / float(ticksPerSecond)

ticks = 0
frames = 0

lastTimer = time.time() * 1000
delta = 0.0

while True:
now = time.time() * 1000000000
delta += float(now - lastTime) / float(nsPerTick)
lastTime = now
shouldRender = False

while delta >= 1:
ticks += 1
main.TICKS += 1
tick()
delta -= 1
shouldRender = True

if shouldRender:
frames += 1
render()

if time.time() * 1000 - lastTimer >= 1000:
lastTimer += 1000

# debug
# print("Frames: " + str(frames) + ", ticks: " + str(ticks))

frames = 0
ticks = 0

# main variable
main = dummy()
init()

# start program
run()``````