Repeat

A tutorial for Python and Pygame Zero 1.2

Rules

Watch as a sequence of numbers flash.

Repeat the sequence using the number keys.

If you successfully repeat the sequence, a new number is added and the sequence flashes again

Coding

Sequence

The sequence list is created. For now it contains a test sequence of numbers between 1 and 4.

Full code at this point

sequence = [4, 3, 1, 2, 2, 3] # Temporary

def draw():
    screen.fill((0, 0, 0))

    screen.draw.text(', '.join(map(str, sequence)), (0, 0))

Current position in sequence

The current sequence position starts at 1.

If the number in the sequence at the current position is pressed, then 1 is added to the current position.

This will error once the current position is beyond the length of the sequence list.

Full code at this point

sequence = [4, 3, 1, 2, 2, 3] # Temporary
current = 0

def on_key_down(key):
    global current

    if key in (keys.K_1, keys.K_2, keys.K_3, keys.K_4):
        if key == keys.K_1:
            number = 1
        elif key == keys.K_2:
            number = 2
        elif key == keys.K_3:
            number = 3
        elif key == keys.K_4:
            number = 4

        if number == sequence[current]:
            current += 1

def draw():
    screen.fill((0, 0, 0))

    screen.draw.text(', '.join(map(str, sequence)), (0, 0))
    screen.draw.text(str(current + 1) + '/' + str(len(sequence)), (0, 20))
    screen.draw.text('sequence[current]: ' + str(sequence[current]), (0, 40))

Resetting current position

When the current position goes beyond the sequence length, it is reset to 0.

Full code at this point

def on_key_down(key):
    global current

    if key in (keys.K_1, keys.K_2, keys.K_3, keys.K_4):
        # etc.

        if number == sequence[current]:
            current += 1
            if current == len(sequence):
                current = 0

Adding to sequence

When the current position is reset, a random number between 1 and 4 is added to the sequence.

The random module is imported so that random.randint can be used.

Full code at this point

def on_key_down(key):
    # etc.

            if current == len(sequence):
                current = 0
                sequence.append(random.randint(1, 4))

Starting sequence with a single number

The sequence is now created with a single random number.

Because the code for adding a random number to the sequence is reused, it is made into a function.

Full code at this point

sequence = []

def add_to_sequence():
    sequence.append(random.randint(1, 4))

add_to_sequence()

# etc.

def on_key_down(key):
    # etc.

            if current == len(sequence):
                current = 0
                add_to_sequence()

Resetting the game

A function is made which sets the initial state of the game.

This function is called before the game begins and when an incorrect number key is pressed.

Full code at this point

def add_to_sequence():
    sequence.append(random.randint(1, 4))

def reset():
    global sequence
    global current

    sequence = []
    add_to_sequence()
    current = 0

reset()

def on_key_down(key):
    global current

    if key in (keys.K_1, keys.K_2, keys.K_3, keys.K_4):

        # etc.

        if number == sequence[current]:
            current += 1
            if current == len(sequence):
                current = 0
                add_to_sequence()
        else:
            reset()

Drawing first square

The first square is drawn with a dark red square and a white number.

Full code at this point

def draw():
    screen.fill((0, 0, 0))

    square_size = 50

    screen.draw.filled_rect(
        Rect(0, 0, square_size, square_size),
        color=(50, 0, 0)
    )
    screen.draw.text('1', (19, 18))

    screen.draw.text(str(current + 1) + '/' + str(len(sequence)), (20, 60))
    screen.draw.text('sequence[current]: ' + str(sequence[current]), (20, 100))
    screen.draw.text(', '.join(map(str, sequence)), (20, 140))

Drawing all squares

The rest of the squares are drawn similarly.

Full code at this point

def draw():
    screen.fill((0, 0, 0))

    square_size = 50

    screen.draw.filled_rect(
        Rect(0, 0, square_size, square_size),
        color=(50, 0, 0)
    )
    screen.draw.text('1', (19, 18))

    screen.draw.filled_rect(
        Rect(square_size, 0, square_size, square_size),
        color=(0, 50, 0)
    )
    screen.draw.text('2', (square_size + 21, 18))

    screen.draw.filled_rect(
        Rect(square_size * 2, 0, square_size, square_size),
        color=(0, 0, 50)
    )
    screen.draw.text('3', (square_size * 2 + 21, 18))

    screen.draw.filled_rect(
        Rect(square_size * 3, 0, square_size, square_size),
        color=(50, 50, 0)
    )
    screen.draw.text('4', (square_size * 3 + 21, 18))

    # etc.

Simplifying code

The code for drawing each square is similar, so it is made into a function.

Full code at this point

def draw():
    screen.fill((0, 0, 0))

    def draw_square(number, color):
        square_size = 50
        screen.draw.filled_rect(
            Rect(square_size * (number - 1), 0, square_size, square_size),
            color=color
        )
        screen.draw.text(str(number), (square_size * (number - 1) + 21, 18))

    draw_square(1, (50, 0, 0))
    draw_square(2, (0, 50, 0))
    draw_square(3, (0, 0, 50))
    draw_square(4, (50, 50, 0))

    # etc.

Timer

Numbers will flash every second.

A timer variable starts at 0 and increases by dt each frame.

When the timer is at or above 1 it is reset to 0.

For now, 'tick' is printed every time the numbers will flash.

Full code at this point

def reset():
    # etc.
    global timer

    # etc.
    timer = 0

def update(dt):
    global timer

    timer += dt
    if timer >= 1:
        timer = 0
        # Temporary
        print('tick')

Flashing squares

The current sequence position is reused to flash each square in the sequence.

The timer is used to advance the current sequence position.

For now, the square corresponding to the number at the current sequence position is drawn using its color, while the other squares are drawn in black.

The test sequence from before is used again.

This will error once current goes beyond the length of sequence.

Full code at this point

def reset():
    # etc.

    sequence = [4, 3, 1, 2, 2, 3] # Temporary

def update(dt):
    global timer
    global current

    timer += dt
    if timer >= 1:
        timer = 0
        current += 1

def draw():
    screen.fill((0, 0, 0))

    def draw_square(number, color):
        if number == sequence[current]:
            square_color = color
        else:
            square_color = (0, 0, 0)

        square_size = 50
        screen.draw.filled_rect(
            Rect(square_size * (number - 1), 0, square_size, square_size),
            color=square_color
        )
        screen.draw.text(str(number), (square_size * (number - 1) + 21, 18))

    # etc.

Flashing color

The squares are given a highlighted color for flashing.

Full code at this point

def draw():
    screen.fill((0, 0, 0))

    def draw_square(number, color, color_flashing):

        if number == sequence[current]:
            square_color = color_flashing
        else:
            square_color = color

        square_size = 50
        screen.draw.filled_rect(
            Rect(square_size * (number - 1), 0, square_size, square_size),
            color=square_color
        )
        screen.draw.text(str(number), (square_size * (number - 1) + 21, 18))

    draw_square(1, (50, 0, 0), (255, 0, 0))
    draw_square(2, (0, 50, 0), (0, 255, 0))
    draw_square(3, (0, 0, 50), (0, 0, 255))
    draw_square(4, (50, 50, 0), (255, 255, 0))

    # etc.

Watch and repeat

A variable is created which indicates whether the squares are flashing ('watch') or whether the player is inputing numbers ('repeat').

The state starts as 'watch' and changes to 'repeat' after the flashing sequence has ended.

The keyboard input code is only run if the state is 'repeat'.

Once the sequence has been successfully entered, the state changes back to 'watch'.

Full code at this point

def reset():
    global state

    # etc.

    state = 'watch' # 'watch', 'repeat'

def update(dt):
    global timer
    global current
    global state

    if state == 'watch':
        timer += dt
        if timer >= 1:
            timer = 0
            current += 1
            if current == len(sequence):
                state = 'repeat'
                current = 0

def on_key_down(key):
    global current
    global state

    if state == 'repeat':
        if key in (keys.K_1, keys.K_2, keys.K_3, keys.K_4):

            if key == keys.K_1:
                number = 1
            elif key == keys.K_2:
                number = 2
            elif key == keys.K_3:
                number = 3
            elif key == keys.K_4:
                number = 4

            if number == sequence[current]:
                current += 1
                if current == len(sequence):
                    current = 0
                    add_to_sequence()
                    state = 'watch'
            else:
                reset()

def draw():
    screen.fill((0, 0, 0))

    def draw_square(number, color, color_flashing):

        if state == 'watch' and number == sequence[current]:
            square_color = color_flashing
        else:
            square_color = color

    # etc.

    screen.draw.text('state: ' + state, (20, 180))

Momentary flashing

A boolean variable is used to indicate whether to set the highlighted color or not.

It starts off as False, gets toggled to True when the timer ticks, and gets toggled back to False when the timer ticks again.

The timer limit is changed to tick twice as fast.

Full code at this point

def reset():
    # etc.
    global flashing

    # etc.
    flashing = False

def update(dt):
    global timer
    global current
    global state
    global flashing

    if state == 'watch':
        timer += dt
        if timer >= 0.5:
            timer = 0
            flashing = not flashing
            if not flashing:
                current += 1
                if current == len(sequence):
                    state = 'repeat'
                    current = 0

def draw():
    screen.fill((0, 0, 0))

    def draw_square(number, color, color_flashing):

        if state == 'watch' and flashing and number == sequence[current]:
            square_color = color_flashing
        else:
            square_color = color

    # etc.

    screen.draw.text('flashing: ' + str(flashing), (20, 220))

Game over state

If the wrong key is pressed, instead of resetting the game immediately, the state is set to 'gameover'. When a key is pressed in the 'gameover' state, the game is then reset.

Full code at this point

def on_key_down(key):
    global current
    global state

    if state == 'repeat':
        if key in (keys.K_1, keys.K_2, keys.K_3, keys.K_4):
            # etc.

            if number == sequence[current]:
                # etc.
            else:
                state = 'gameover'
    elif state == 'gameover':
        reset()

Displaying text based on state

The current sequence position and the length of the sequence is only displayed if the game is in the 'repeat' state, and a game over message is shown if the game is in the 'gameover' state.

Full code at this point

def draw():
    # etc.

    if state == 'repeat':
        screen.draw.text(str(current + 1) + '/' + str(len(sequence)), (20, 60))
    elif state == 'gameover':
        screen.draw.text('Game over!', (20, 60))

    # Removed: screen.draw.text('sequence[current]: ' + str(sequence[current]), (20, 100))
    # Removed: screen.draw.text(', '.join(map(str, sequence)), (20, 140))
    # Removed: screen.draw.text('state: ' + state, (20, 180))
    # Removed: screen.draw.text('flashing: ' + str(flashing), (20, 220))