6. Lights Out
Lights Out; See http://www.multiwingspan.co.uk/micro.php?page=lights
The game below is an easier version of the the original.
6.1. Bitwise operations to reverse 0 and 1
The on/off lights are stored as a 2D list of 1s and 0s.
In order to make the moves, the XOR operator, ^, is used.
The bitwise xor operator returns 1 if the bits are different; 0 if the same.
Note, bitwise operations on integers convert the integers to binary, carry out the bitwise operation, convert the binary number back to an integer and return the integer.
The code below shows the different possible results from using the bitwise XOR, ^, and the assignment operator, ^=, for 0s and 1s.
print(0 ^ 0) # 0
print(0 ^ 1) # 1
print(1 ^ 0) # 1
print(1 ^ 1) # 0
x = 0
x ^= 0
print(x) # 0
x = 0
x ^= 1
print(x) # 1
x = 1
x ^= 0
print(x) # 1
x = 1
x ^= 1
print(x) # 0
6.2. Grid referencing
A grid, where each pixel is referenced using the x and y coordinates, makes it easy to change the pixels relative to the player pixel, (x, y).
In the grid code below, each pixel is referenced by
grid[x][y].In the grid array below, the first column in grid[0].
grid = [
[0, 0, 0, 0, 0],
[0, 0, 0, 0, 0],
[0, 0, 0, 0, 0],
[0, 0, 0, 0, 0],
[0, 0, 0, 0, 0],
]
6.3. Lights Out Outline
Tasks
Here is the outline to the Lights Out code. The game loop has been provided. See if you can write code for each method in the classes to get the game working. SOme of the key code has been kept. Comments guide you to the rest of what is needed.
from microbit import *
import random
class LightsOut:
def __init__(self, tilt_sensitivity=300, tilt_delay=400, x=2, y=2)
# initialize the parameters
# set the brightness and the grid
def ToggleX(self, tx=None, ty=None):
"""toggle all in same row"""
if tx is None:
tx = self.x
if ty is None:
ty = self.y
# toggle the pixels in the row
def ToggleY(self, tx=None, ty=None):
"""toggle all in same column"""
if tx is None:
tx = self.x
if ty is None:
ty = self.y
# toggle the pixels in the column
def ToggleXY(self, tx=None, ty=None):
"""toggle all in same row and all in same column"""
if tx is None:
tx = self.x
if ty is None:
ty = self.y
# toggle the pixels in the row
# toggle the pixels in the column
def RandomGrid(self):
#staring with random x and random y pixels use ToggleXY a random number of times from 4 to 30
def DrawGame(self):
"""Add pixels from grid one at a time at brightness, gb, of 3
b is 0 or 9, player pixel will be 0 or 9 if pixel not in grid, or 7 or 9 is in self.grid.
"""
gb = 3
img = Image("00000:" * 5)
# set pixels brightness in img from grid
# add player pixel depending on whether b is 0 or 9, player pixel will be 0 or 9 if pixel not in grid, or 7 or 9 is in self.grid
# display image and sleep for tilt_delay
def CheckWin(self):
"""Return True if all points in grid are 0"""
tot = 0
# add grid values
# Return True if all points in grid are 0; or False if not
def MovePlayer(self):
'''alternate between 0 and 9 for brightness'''
self.brightness = 9 - self.brightness
dx = accelerometer.get_x()
dy = accelerometer.get_y()
# move based on dx and dy
# keep on grid
game = LightsOut(tilt_sensitivity=300, tilt_delay=400, x=2, y=2)
game.RandomGrid()
playing = True
while playing:
game.MovePlayer()
game.DrawGame()
if button_a.was_pressed():
game.ToggleX()
game.DrawGame()
elif button_b.was_pressed():
game.ToggleY()
game.DrawGame()
if game.CheckWin():
playing = False
sleep(500)
for w in range(0, 3):
display.show(Image.HAPPY)
sleep(300)
display.clear()
sleep(300)
6.4. Working code
The working code is below.
from microbit import *
import random
class LightsOut:
def __init__(self):
self.tilt_sensitivity = 300
self.tilt_delay = 400
self.x = 2
self.y = 2
self.brightness = 0
"""grid[tx][ty]; the grid array has the first column in grid[0]"""
self.grid = [
[0, 0, 0, 0, 0],
[0, 0, 0, 0, 0],
[0, 0, 0, 0, 0],
[0, 0, 0, 0, 0],
[0, 0, 0, 0, 0],
]
def Toggle5(self, tx=None, ty=None):
"""For original game only; toggle all 5 points, if they exist, above, below and to the sides of a point"""
if tx is None:
tx = self.x
if ty is None:
ty = self.y
self.grid[tx][ty] ^= 1
if tx > 0:
self.grid[tx - 1][ty] ^= 1
if tx < 4:
self.grid[tx + 1][ty] ^= 1
if ty > 0:
self.grid[tx][ty - 1] ^= 1
if ty < 4:
self.grid[tx][ty + 1] ^= 1
def ToggleX(self, tx=None, ty=None):
"""toggle all in same row"""
if tx is None:
tx = self.x
if ty is None:
ty = self.y
for x in range(5):
self.grid[x][ty] ^= 1
def ToggleY(self, tx=None, ty=None):
"""toggle all in same column"""
if tx is None:
tx = self.x
if ty is None:
ty = self.y
for y in range(5):
self.grid[tx][y] ^= 1
def ToggleXY(self, tx=None, ty=None):
"""toggle all in same row and all in same column"""
if tx is None:
tx = self.x
if ty is None:
ty = self.y
for x in range(5):
self.grid[x][ty] ^= 1
for y in range(5):
self.grid[tx][y] ^= 1
def RandomGrid(self):
"""use ToggleXY a random number of times from 4 to 30"""
# use ToggleXY at random pixels 4 to 30 times
def DrawGame(self):
"""Add pixels from grid one at a time at brightness, gb, of 3.
b is 0 or 9, player pixel will be 0 or 9 if pixel not in grid, or 7 or 9 is in self.grid.
"""
gb = 3
img = Image("00000:" * 5)
for cy in range(0, 5):
for cx in range(0, 5):
img.set_pixel(cx, cy, self.grid[cx][cy] * gb)
# add player pixel
if img.get_pixel(self.x, self.y) == gb:
if self.brightness == 0:
img.set_pixel(self.x, self.y, 7)
else:
img.set_pixel(self.x, self.y, self.brightness)
else:
img.set_pixel(self.x, self.y, self.brightness)
# return img
display.show(img)
sleep(self.tilt_delay)
def CheckWin(self):
"""Return True if all all points in grid are 0.
Also can do: print(sum([sum(i) for i in grid]))
"""
tot = 0
for cy in range(0, 5):
for cx in range(0, 5):
tot += self.grid[cx][cy]
if tot == 0:
return True
else:
return False
def MovePlayer(self):
'''alternate between 0 and 9 for brightness'''
self.brightness = 9 - self.brightness
dx = accelerometer.get_x()
dy = accelerometer.get_y()
if dx > self.tilt_sensitivity:
self.x += 1
if dx < -self.tilt_sensitivity:
self.x -= 1
if dy > self.tilt_sensitivity:
self.y += 1
if dy < -self.tilt_sensitivity:
self.y -= 1
# keep on grid
self.x = max(0, min(self.x, 4))
self.y = max(0, min(self.y, 4))
game = LightsOut()
game.RandomGrid()
playing = True
while playing:
game.MovePlayer()
game.DrawGame()
if button_a.was_pressed():
game.ToggleX()
game.DrawGame()
elif button_b.was_pressed():
game.ToggleY()
game.DrawGame()
if game.CheckWin():
playing = False
sleep(500)
for w in range(0, 3):
display.show(Image.HAPPY)
sleep(300)
display.clear()
sleep(300)
6.5. How To Beat The Original Game
The original game is a puzzle game that takes many moves to solve.
The original code used toggling of the 5 pixels in a cross shape and is included below for reference.
from microbit import *
import random
def Toggle5(self, tx=None, ty=None):
"""For original game only; toggle all 5 points, if they exist, above, below and to the sides of a point"""
if tx is None:
tx = self.x
if ty is None:
ty = self.y
self.grid[tx][ty] ^= 1
if tx > 0:
self.grid[tx - 1][ty] ^= 1
if tx < 4:
self.grid[tx + 1][ty] ^= 1
if ty > 0:
self.grid[tx][ty - 1] ^= 1
if ty < 4:
self.grid[tx][ty + 1] ^= 1
Jaap Scherphuis explained the solution on his site at http://www.jaapsch.net/puzzles/lights.htm.
Stage 1 - Chase The Lights
Start at the top row. For every light that is on, select the light beneath it. Do this with the next 4 rows. If you are really lucky, this will solve the puzzle. If not, there will be a couple of lights on the bottom row and stage 2 and 3 will need to be done.
Stage 2 - Set Up For The Win
Look at the first 3 LEDs on the bottom row.
If LED(0, 4) is on, press LED(3, 0) and LED(4, 0). These are the 4th and 5th lights of the top row.
If LED(1, 4) is on, press LED(1, 0) and LED(4, 0). These are the 2nd and 5th lights of the top row.
If LED(2, 4) is on, press LED(3, 0). This is the 4th light on the top row.
Stage 3 - Chase The Lights Again
Repeat the chase the lights process again with the lights that are now on. By the time you get to the bottom row, the lights should all be out and you win.