BBC micro:bit – Tetris Game

For this challenge we are creating a game of Tetris to play on the BBC micro:bit.

The game will be based on the following four shapes:

The game will use the following inputs:

• Button A: Move current brick to the left
• Button B: Move current brick to the right
• Button A and B simultaneously: Rotate current brick clockwise

Video Demo

The game will use the LED screen which consists of a 5×5 grid of 25 LEDs.
Each LED can be on (value: 9 for maximum brightness) or Off (value: 0)
The side/borders of the grid will note be displayed.

The Python code will use 2-dimension arrays (list of lists in Python) to store the main grid (7×5) and the current brick (2×2)

To test this code you will need to use the Python Editor from the micro:bit website.

Python Code

from microbit import *
from random import choice

#Set up the tetris grid
grid=[[1,0,0,0,0,0,1],[1,0,0,0,0,0,1],[1,0,0,0,0,0,1],[1,0,0,0,0,0,1],[1,0,0,0,0,0,1],[1,1,1,1,1,1,1]]
#Store a list of 4 bricks, each brick is a 2x2 grid
bricks = [[9,9],[9,0]],[[9,9],[0,9]],[[9,9],[9,9]],[[9,9],[0,0]]
#select a brick randomly and position it at the center/top of the grid (y=0,x=3)
brick = choice(bricks)
x=3
y=0
frameCount=0

#A function to return the maximum of two values
def max(a,b):
    if a>=b:
        return a
    else:
        return b
        
#A function to hide the 2x2 brick on the LED screen
def hideBrick():
    if x>0:
        display.set_pixel(x-1,y,grid[y][x])
    if x<5:
        display.set_pixel(x+1-1,y,grid[y][x+1])
    if x>0 and y<4:
        display.set_pixel(x-1,y+1,grid[y+1][x])
    if x<5 and y<4:
        display.set_pixel(x+1-1,y+1,grid[y+1][x+1])
        
#A function to show the 2x2 brick on the LED screen
def showBrick():
    if x>0:
        display.set_pixel(x-1,y,max(brick[0][0],grid[y][x]))
    if x<5:
        display.set_pixel(x+1-1,y,max(brick[0][1],grid[y][x+1]))
    if x>0 and y<4:
        display.set_pixel(x-1,y+1,max(brick[1][0],grid[y+1][x]))
    if x<5 and y<4:   
        display.set_pixel(x+1-1,y+1,max(brick[1][1],grid[y+1][x+1]))

#A function to rotate the 2x2 brick
def rotateBrick():
    pixel00 = brick[0][0]
    pixel01 = brick[0][1]
    pixel10 = brick[1][0]
    pixel11 = brick[1][1]
    #Check if the rotation is possible
    if not ((grid[y][x]>0 and pixel00>0) or (grid[y+1][x]>0 and pixel10>0) or (grid[y][x+1]>0 and pixel01>0) or (grid[y+1][x+1]>0 and pixel11>0)):
        hideBrick()        
        brick[0][0] = pixel10
        brick[1][0] = pixel11
        brick[1][1] = pixel01
        brick[0][1] = pixel00
        showBrick()     

#A function to move/translate the brick
def moveBrick(delta_x,delta_y):
    global x,y
    move=False
    #Check if the move if possible: no collision with other blocks or borders of the grid
    if delta_x==-1 and x>0:
        if not ((grid[y][x-1]>0 and brick[0][0]>0) or (grid[y][x+1-1]>0 and brick[0][1]>0) or (grid[y+1][x-1]>0 and brick[1][0]>0) or (grid[y+1][x+1-1]>0 and brick[1][1]>0)):
            move=True
    elif delta_x==1 and x<5:
        if not ((grid[y][x+1]>0 and brick[0][0]>0) or (grid[y][x+1+1]>0 and brick[0][1]>0) or (grid[y+1][x+1]>0 and brick[1][0]>0) or (grid[y+1][x+1+1]>0 and brick[1][1]>0)):
            move=True
    elif delta_y==1 and y<4:   
        if not ((grid[y+1][x]>0 and brick[0][0]>0) or (grid[y+1][x+1]>0 and brick[0][1]>0) or (grid[y+1+1][x]>0 and brick[1][0]>0) or (grid[y+1+1][x+1]>0 and brick[1][1]>0)):
            move=True
    #If the move is possible, update x,y coordinates of the brick
    if move:      
        hideBrick()
        x+=delta_x
        y+=delta_y
        showBrick()
        
    #Return True or False to confirm if the move took place
    return move    

#A function to check for and remove completed lines
def checkLines():
    global score
    removeLine=False
    #check each line one at a time
    for i in range(0, 5):
        #If 5 blocks are filled in (9) then a line is complete (9*5=45)
        if (grid[i][1]+grid[i][2]+grid[i][3]+grid[i][4]+grid[i][5])==45:
            removeLine = True
            #Increment the score (10 pts per line)
            score+=10
            #Remove the line and make all lines above fall by 1:
            for j in range(i,0,-1):
                grid[j] = grid[j-1]
            grid[0]=[1,0,0,0,0,0,1]    
    if removeLine:
        #Refresh the LED screen
        for i in range(0, 5):
            for j in range(0, 5):
                display.set_pixel(i,j,grid[j][i+1])
    return removeLine
    
gameOn=True
score=0
showBrick()
#Main Program Loop - iterates every 50ms
while gameOn:
    sleep(50)
    frameCount+=1
    #Capture user inputs
    if button_a.is_pressed() and button_b.is_pressed():
        rotateBrick() 
    elif button_a.is_pressed():
        moveBrick(-1,0)
    elif button_b.is_pressed():
        moveBrick(1,0)
    
    #Every 15 frames try to move the brick down
    if frameCount==15 and moveBrick(0,1) == False:
        frameCount=0
        #The move was not possible, the brick stays in position
        grid[y][x]=max(brick[0][0],grid[y][x])
        grid[y][x+1]=max(brick[0][1],grid[y][x+1])
        grid[y+1][x]=max(brick[1][0],grid[y+1][x])
        grid[y+1][x+1]=max(brick[1][1],grid[y+1][x+1])
        
        if checkLines()==False and y==0:
            #The brick has reached the top of the grid - Game Over
            gameOn=False   
        else:
            #select a new brick randomly
            x=3
            y=0
            brick = choice(bricks)
            showBrick()
    
    if frameCount==15:
       frameCount=0

#End of Game
sleep(2000)
display.scroll("Game Over: Score: " + str(score)) 

Note: When testing this code, you may want to remove some of the #annotations especially if your micro:bit returns a “memory full” error.