4. Press It game

4.1. Game design

Press It is a game to press the A or B button after ‘A’ or ‘B’ is shown.

A class is used to run the game.

Set up the game object
1. Assign values to the LEVEL_SPEED dictionary.
2. Assign values to the LEVELUP tuple.
3. Set the score to 0.
4. Set the level to 1.
Run the game:
1. Show ‘A’ or ‘B’.
2. If the correct button is pressed within the time limit then:
  
  Display a tick (Image.YES).
  
  Add one to the score.
  
  Level up if the next level has been reached.
3. If the wrong button is pressed or no button is pressed within the time limit then:
  
  Display an X (Image.NO).
  
  Scroll the score.

The code uses the class, PressIt(), for the game object.

Only the run_game method is used outside the class itself.

The code below omits the PressIt class for simplicity, but shows the rest of the game code.

The while True loop repeats the game if both buttons have been pressed.

from microbit import *
import random

game = PressIt()
game.run_game()
while True:
    if button_a.was_pressed() and button_b.was_pressed():
        game = PressIt()
        game.run_game()
    else:
        sleep(2000)

4.2. The PressIt class

Use a class for the game object.

class PressIt: Set up the game object to control the game, including the LEVEL_SPEED dictionary, the LEVELUP tuple, the initial level and score.

The code below imports the random module and creates the game object by creating an instance of the PressIt class.

from microbit import *
import random


game = PressIt()

4.3. The PressIt class methods

The PressIt class methods are described below.

show_a() shows ‘A’.
show_b() shows ‘B’.
show_yes() shows a tick, Image.YES.
show_no() shows a cross, Image.NO.
show_start shows ‘A or B’ and the level.
show_levelup() shows an up arrow, Image.ARROW_N, and scrolls the level.
show_score shows the score.
is_correct_button() picks A or B to show then waits according to the duration for the level, and returns True if the correct button has been pressed, otherwise False.
continue_game() calls show_yes() and updates the score and level.
end_game() calls show_no() and show_score() methods
run_game() calls several methods as it checks the correct button is pressed within the time limit and either continues or ends the game.

4.4. The PressIt init method

__init__(): The __init__() method is called when the game object is created and initializes the instance varaibles.

score is set to 0.

level is set to 1.

The __init__ method is given below.

class TiltPixels:

    def __init__(self):
        self.score = 0
        self.level = 1

4.5. The PressIt class constants

The class constants are in capitals: LEVEL_SPEED and LEVELUP.
LEVEL_SPEED is a dictionary with the level number as the key and the duration in milliseconds. The duration specifies the time the player has to press a button. e.g for 1: 1200, the key is 1 and the duration is 1200.
LEVELUP is a tuple of numbers for when the level is increased. e.g. after 3 correct button presses the level goes up 1. There are only 8 numbers even though there are 9 levels, since there can only be 8 level ups from level 1 to level 9.

class TiltPixels:

    LEVEL_SPEED = {1: 1200, 2: 1000, 3: 800, 4: 700, 5: 600, 6: 550, 7: 500, 8: 450, 9: 400}
    LEVELUP = (3, 6, 9, 12, 15, 18, 21, 24)

4.6. Game code

The game code is below.

"""PressIt_game: Press the A or B button when the text is shown"""

from microbit import *
import random


class PressIt():

    LEVEL_SPEED = {1: 1200, 2: 1000, 3: 800, 4: 700, 5: 600, 6: 550, 7: 500, 8: 450, 9: 400}
    LEVELUP = (3, 6, 9, 12, 15, 18, 21, 24)

    def __init__(self):
        self.score = 0
        self.level = 1

    def show_a(self):
        display.show("A")

    def show_b(self):
        display.show("B")

    def show_yes(self):
        display.show(Image.YES)
        sleep(500)

    def show_no(self):
        display.show(Image.NO)
        sleep(500)

    def show_levelup(self):
        display.show(Image.ARROW_N)
        display.scroll('level ' + str(self.level), delay=60)
        sleep(500)

    def is_correct_button(self):
        button_number = random.randint(0, 1)
        if button_number == 0:
            self.show_a()
        elif button_number == 1:
            self.show_b()
        a_pressed = False
        b_pressed = False
        start_time = running_time()
        now = running_time()
        while now - start_time < self.LEVEL_SPEED[self.level]:
            if button_a.is_pressed():
                a_pressed = True
            if button_b.is_pressed():
                b_pressed = True
            now = running_time()
        if button_number == 0:
            if a_pressed is True and b_pressed is False:
                return True
            else:
                return False
        elif button_number == 1:
            if a_pressed is False and b_pressed is True:
                return True
            else:
                return False

    def continue_game(self):
        self.show_yes()
        self.score += 1
        if self.score in self.LEVELUP:
            self.level += 1
            self.show_levelup()

    def end_game(self):
        self.show_no()
        self.show_score()

    def run_game(self):
        self.show_start()
        game_over = False
        while game_over is False:
            if self.is_correct_button():
                self.continue_game()
            else:
                game_over = True
                self.end_game()

game = PressIt()
game.run_game()
while True:
    if button_a.was_pressed() and button_b.was_pressed():
        game = PressIt()
        game.run_game()
    else:
        sleep(2000)

Tasks

Modify the code to display left and right arrows instead of ‘A’ and ‘B’.
Add a rapid animation of 3 to 6 built in image shapes to be shown when the level reaches level 5.
Replace the level scrolled text with an animation in which the number of images in the animation is equal to the level number.
Add code to store all the game scores and display the average score after each game.
Add code to store the best game score after each game and display the best score after exiting by pressing both buttons.