#1: How to Build a Classic Tetris Game with Pygame * bigfinish.com

Embark on a captivating programming adventure with this comprehensive guide to crafting your very own Tetris masterpiece using the versatile Pygame library. This classic game, with its minimalist yet addictive gameplay, has enthralled generations of gamers worldwide. Now, you have the opportunity to delve into the intricacies of game development and bring the legendary Tetris to life on your computer screen.

The journey begins with an introduction to Pygame, the python-based framework that will serve as the foundation for your Tetris game. We will explore the fundamentals of game loops, event handling, and graphics rendering in Pygame, ensuring that your game runs smoothly and responds to player input effectively. Additionally, you will learn essential techniques for managing game objects, collision detection, and score tracking.

As you progress, we will delve into the core gameplay mechanics of Tetris. We will discuss how to generate the iconic falling Tetrominoes (game pieces), define their movement rules, and implement collision detection with the game board. You will discover how to handle line clearing, level progression, and the game over condition, creating a complete and engaging Tetris experience for your players.

Setting Up Pygame

To embark on our Tetris adventure using Pygame, we first need to set the stage by installing this essential library. Pygame offers a comprehensive toolkit for creating engaging games in Python. Here’s a step-by-step guide to get you started:

1. Install Pygame using your preferred package manager. For example, if you’re using pip, run the command “pip install pygame” in your terminal or command prompt.

2. Import the Pygame library into your Python script. At the beginning of your code, include the following line: “import pygame”. This line brings Pygame’s vast arsenal of functions and classes into your coding realm.

3. Initialize Pygame. This critical step activates Pygame and prepares it for use. Call the “pygame.init()” function to awaken Pygame’s powers.

Here’s a simple example to illustrate the process:

Code	Description
`import pygame`	Import the Pygame library.
`pygame.init()`	Initialize Pygame.

Creating the Game Window

To create the game window, we use the pygame.display.set_mode() function. This function takes a tuple as an argument, representing the width and height of the window in pixels. For example, the following code creates a game window that is 800 pixels wide and 600 pixels high:

import pygame


# Initialize Pygame

pygame.init()
# Create the game window

window = pygame.display.set_mode((800, 600))

# Set the window title pygame.display.set_caption("Tetris")

Once the game window has been created, we can use the pygame.display.update() function to update the display and draw the game elements. The pygame.display.update() function takes a list of surfaces as an argument, representing the surfaces that we want to update. For example, the following code updates the display and draws a black background:

# Create a black surface black_surface = pygame.Surface((800, 600)) black_surface.fill((0, 0, 0))

# Update the display pygame.display.update([black_surface])

We can also use the pygame.event.get() function to check for events, such as mouse clicks and keyboard presses. The pygame.event.get() function returns a list of events that have occurred since the last time it was called. For example, the following code checks for events and prints the event type and the position of the mouse cursor:

# Check for events events = pygame.event.get()

# Print the event type and the position of the mouse cursor for each event for event in events: print(event.type, event.pos)

Drawing the Tetris Pieces

The Tetris pieces are made up of four squares, each of which is a different color. The pieces are drawn using the pygame.draw.rect() function. The following code shows how to draw a Tetris piece:

Drawing Vertical Tetris Pieces

To draw the verticale Tetris piece all you need to do is figure out the distance between each square, then for each part of the Tetris piece draw a square with different colors alternately. Here is a table with the dimensions:

Vertical Tetris Piece	Colors
	Blue, Green, Red, Yellow
	Blue, Green, Red, Yellow
	Blue, Green, Red, Yellow
	Blue, Green, Red, Yellow

Drawing Horizontal Tetris Pieces

To draw the horizontal Tetris piece all you need to do is figure out the distance between each square, then similar to the vertical piece, for each part of the Tetris piece draw a square with different colors alternately. Here is a table with the dimensions:

Horizontal Tetris Piece	Colors
	Green, Red, Blue, Yellow
	Green, Red, Blue, Yellow
	Green, Red, Blue, Yellow
	Green, Red, Blue, Yellow

Drawing Square Tetris Pieces

To draw the square Tetris piece all you need to do is figure out the distance between each square, then similar to the previous pieces, for each part of the Tetris piece draw a square with different colors alternately. Here is a table with the dimensions:

Square Tetris Piece	Colors
	Green, Red, Blue, Yellow
	Green, Red, Blue, Yellow
	Green, Red, Blue, Yellow
	Green, Red, Blue, Yellow

Handling Player Input

Handling player input is crucial for creating an interactive Tetris game. Pygame provides various event-handling functions that allow you to listen for user actions and respond accordingly.

One common approach is to use keyboard events. Listen for the following key presses:

Up Arrow

Used to rotate the falling tetromino

Down Arrow

Used to accelerate the falling tetromino

Left Arrow

Used to move the falling tetromino left

Right Arrow

Used to move the falling tetromino right

Spacebar

Used to hard drop the falling tetromino

Additionally, you can use the following event types:

Event Type	Description
KEYDOWN	Triggered when a key is pressed
KEYUP	Triggered when a key is released
QUIT	Triggered when the user tries to close the game window

By processing these events, you can capture player actions and manipulate the game state accordingly, ensuring a responsive and enjoyable Tetris experience.

Implementing Game Physics

The game physics engine is responsible for simulating the movement and interactions of the game objects. In Tetris, the game physics engine must handle the following tasks:

Falling blocks
Collision detection
Rotation
Gravity

Falling Blocks

Blocks fall at a constant speed. The speed of the falling blocks can be increased or decreased to make the game easier or harder. When a block reaches the bottom of the screen, it is added to the game board.

Collision Detection

Collision detection is used to determine when a block has collided with another block or the edge of the game board. When a block collides with another block, it will stop moving. When a block collides with the edge of the game board, it will bounce off.

Rotation

Blocks can be rotated clockwise or counterclockwise. Rotation is used to change the orientation of a block so it can fit into a space in the game board.

Gravity

Gravity pulls blocks down towards the bottom of the screen. Gravity is what causes blocks to fall. The strength of gravity can be changed to make the game easier or harder.

Block Properties

The following table lists the properties of the blocks in Tetris:

Property	Description
Shape	The shape of the block.
Size	The size of the block.
Color	The color of the block.
Rotation	The rotation of the block.
Speed	The speed of the block.

6. Handling Collisions

The core of a Tetris game lies in detecting collisions effectively. Pygame provides several methods to handle this crucial aspect, and we will delve into each one in detail.

1. Rect.colliderect()

This method is used to check for collisions between two rectangles. It takes two rectangle objects as arguments and returns True if they intersect, otherwise it returns False.

2. Rect.collidelist()

This method checks for collisions between a rectangle and a list of other rectangles. It takes a list of rectangle objects as an argument and returns the index of the first rectangle that it collides with. If no collision is found, it returns -1.

3. Rect.collidelistall()

This method is similar to collidelist(), but it returns a list of indices of all the rectangles that the given rectangle collides with.

4. Rect.clip()

This method creates a new rectangle object that represents the overlapping area between two rectangles. If there is no overlap, it returns None.

5. Rect.union()

This method creates a new rectangle object that represents the union of two rectangles. This is useful for creating a bounding box around a group of objects.

6. pygame.sprite.spritecollide()

Pygame provides a convenient way to manage sprites, which are objects that can be drawn and updated. The spritecollide() function takes a sprite group and a rectangle object as arguments, and returns a list of all the sprites in the group that collide with the rectangle.

Method	Purpose
Rect.colliderect()	Check for collisions between two rectangles.
Rect.collidelist()	Check for collisions between a rectangle and a list of other rectangles.
Rect.collidelistall()	Check for collisions between a rectangle and a list of other rectangles, returning a list of indices of all collisions.
Rect.clip()	Create a new rectangle object representing the overlapping area between two rectangles.
Rect.union()	Create a new rectangle object representing the union of two rectangles.
pygame.sprite.spritecollide()	Check for collisions between a sprite group and a rectangle object.

Rotating Tetris Pieces

The rotation of Tetris pieces is one of the key gameplay mechanics that makes the game so engaging. It allows players to position pieces in a variety of ways, increasing the possibilities for creating lines and scoring points.

In Pygame, the rotation of Tetris pieces is handled by the `pygame.transform.rotate()` function. This function takes a Pygame surface as its first argument and an angle as its second argument. The angle is specified in degrees, and it represents the amount of rotation that will be applied to the surface.

To rotate a Tetris piece, you can use the following steps:

Step	Action
1	Create a Pygame surface for the Tetris piece.
2	Draw the Tetris piece on the surface.
3	Get the angle of the Tetris piece.
4	Call the `pygame.transform.rotate()` function to rotate the surface by the angle.
5	Blit the rotated surface onto the game screen.

Generating New Pieces

In Tetris, the game continuously generates new pieces that fall down the playing field. These pieces are randomly chosen from a set of seven different shapes, or tetrominoes.

To generate a new piece, we use the random.choice() function to randomly select one of the seven tetrominoes. Each tetromino is represented by a list of coordinates, which define the shape of the piece.

Once we have selected a tetromino, we need to rotate it randomly. This is done to ensure that the pieces do not always fall in the same orientation. To rotate a tetromino, we use the numpy.rot90() function, which rotates the piece by 90 degrees.

After the tetromino has been rotated, we need to translate it to the top of the playing field. This is done by adding the (0, 4) tuple to the coordinates of the piece. The (0, 4) tuple represents the offset from the top-left corner of the playing field to the center of the piece.

Here is a more detailed explanation of the steps involved in generating a new piece:

1. Select a tetromino

“`python
tetromino = random.choice(tetrominoes)
“`

2. Rotate the tetromino

“`python
tetromino = numpy.rot90(tetromino)
“`

3. Translate the tetromino

“`python
tetromino += (0, 4)
“`

4. Return the tetromino

“`python
return tetromino
“`

Scoring and Leveling

Scoring in Tetris is crucial to track your progress and keep you motivated. Each completed line earns you points. For higher scores, clear multiple lines at once. Removing a single line earns you 40 points, while clearing two, three, or four lines simultaneously nets you 100, 300, or 1200 points, respectively.

As you accumulate points, you level up, increasing the difficulty of the game. You start at level 1 with a speed of 300 milliseconds per piece drop. With each level, the drop speed decreases by 20 milliseconds, making the gameplay progressively more challenging.

Here’s a breakdown of score and level progression:

Level	Drop Speed (milliseconds)	Points Needed to Level Up
1	300	2000
2	280	4000
3	260	6000
4	240	8000
5	220	10000
…	…	…
10	140	20000

Game Over

When the game is over, you need to display a game over screen. This screen should tell the player that the game is over and provide them with an option to restart the game. You can use the following code to display a game over screen:

import pygame

# Initialize the game engine
pygame.init()

# Define the colors we will use in RGB format
BLACK = (  0,   0,   0)
WHITE = (255, 255, 255)
BLUE =  (  0,   0, 255)
GREEN = (  0, 255,   0)
RED =   (255,   0,   0)

# Set the height and width of the screen
size = [400, 500]
screen = pygame.display.set_mode(size)

# Loop until the user clicks the close button.
done = False
clock = pygame.time.Clock()

# Speed in pixels per second
x_speed = 0
y_speed = 0

# Current position
x_coord = 100
y_coord = 100

# Set the initial speed
speed = 0.1

# Loop as long as done == False
while not done:
    # This limits the while loop to a max of 60 times per second.
    # Leave this out and we will use all CPU we can.
    clock.tick(60)
    
    for event in pygame.event.get():   # User did something
        if event.type == pygame.QUIT:  # If user clicked close
            done = True   # Flag that we are done so we exit this loop
        elif event.type == pygame.KEYDOWN:
            # Figure out if it was an arrow key. If so
            # adjust speed.
            if event.key == pygame.K_LEFT:
                x_speed = -speed
            elif event.key == pygame.K_RIGHT:
                x_speed = speed
            elif event.key == pygame.K_UP:
                y_speed = -speed
            elif event.key == pygame.K_DOWN:
                y_speed = speed
        # User let up on a key
        elif event.type == pygame.KEYUP:
            # If it is an arrow key, reset speed to 0
            if event.key == pygame.K_LEFT or event.key == pygame.K_RIGHT:
                x_speed = 0
            elif event.key == pygame.K_UP or event.key == pygame.K_DOWN:
                y_speed = 0
    # Update the position of the shape
    x_coord += x_speed
    y_coord += y_speed
    
    # Fill the screen with white
    screen.fill(WHITE)
    
    # Draw the shape
    pygame.draw.rect(screen, GREEN, [x_coord, y_coord, 10, 10])
    
    # Go ahead and update the screen with what we've drawn.
    # This MUST happen after all the other drawing commands.
    pygame.display.flip()

# Once we leave the loop, close the window.
pygame.quit()

Restart

When the player clicks on the restart button, you need to reset the game. This means resetting the player’s score, the game board, and the game’s speed. You can use the following code to reset the game:

# Reset the game's speed
speed = 0.1

# Reset the player's score
score = 0

# Reset the game board
board = [[' ' for _ in range(10)] for _ in range(20)]

Once you have reset the game, you can start a new game by calling the startGame() function.

How to Make a Tetris Game Using Pygame

In this article, we will provide a step-by-step guide on how to create a Tetris game using Pygame, a popular Python library for creating video games.

Tetris is a classic puzzle game where players must rotate and drop falling blocks to create horizontal lines without any gaps. The game is engaging and addictive, and it can be a great way to learn basic programming concepts.

Here are the steps involved in creating a Tetris game using Pygame:

Install Pygame
Create a new Pygame project
Define the game window
Create the game board
Create the Tetris blocks
Handle user input
Update the game state
Draw the game
Handle game over

Once you have completed these steps, you will have a working Tetris game that you can play on your computer.