PyGame Pong

main.py

# Import the pygame module
import pygame

# Import pygame.locals for easier access to key coordinates

from pygame.locals import (
    K_UP,
    K_DOWN,
    K_ESCAPE,
    KEYDOWN,
    QUIT,
)

# Initialize pygame
pygame.init()

# Define constants for the screen width and height
SCREEN_WIDTH = 800
SCREEN_HEIGHT = 600


# Create the screen object
# The size is determined by the constant SCREEN_WIDTH and SCREEN_HEIGHT
screen = pygame.display.set_mode((SCREEN_WIDTH, SCREEN_HEIGHT))

# Define a Player object by extending pygame.sprite.Sprite
# The surface drawn on the screen is now an attribute of 'player'
class Player(pygame.sprite.Sprite):
    def __init__(self):
        super(Player, self).__init__()
        self.surf = pygame.Surface((15, 50))
        self.surf.fill((255, 255, 255))
        self.rect = self.surf.get_rect()
        self.rect.left = 15
        self.rect.top = (SCREEN_HEIGHT / 2)

    # Move the sprite based on user keypresses
    def update(self, pressed_keys):
        if pressed_keys[K_UP]:
            self.rect.move_ip(0, -5)

        if pressed_keys[K_DOWN]:
            self.rect.move_ip(0, 5)

        # Keep player on the screen
        if self.rect.left < 0:
            self.rect.left = 0

        if self.rect.right > SCREEN_WIDTH:
            self.rect.right = SCREEN_WIDTH

        if self.rect.top <= 0:
            self.rect.top = 0

        if self.rect.bottom >= SCREEN_HEIGHT:
            self.rect.bottom = SCREEN_HEIGHT

class Ball(pygame.sprite.Sprite):
    x = 2
    y = 1
    def __init__(self):
        super(Ball, self).__init__()
        self.surf = pygame.Surface((10, 10))
        self.surf.fill((255, 255, 255))
        self.rect = self.surf.get_rect()
        self.rect.left = 100
        self.rect.top = (SCREEN_HEIGHT / 2)
    def update(self, pressed_keys):
        self.rect.move_ip(self.x, self.y)

        # Bounce ball against the paddle/player    
        if pygame.sprite.collide_rect(self, player):
            self.x = self.x * -1
            
        # Keep ball on the screen     
        if self.rect.left < 0:
            self.x = self.x * -1

        if self.rect.right > SCREEN_WIDTH:
            self.x = self.x * -1

        if self.rect.top <= 0:
            self.y = self.y * -1

        if self.rect.bottom >= SCREEN_HEIGHT:
            self.y = self.y * -1


# Instantiate player.
player = Player()

# Instantiate ball.
ball = Ball()

# Variable to keep the main loop running
running = True

# Main loop
while running:
    # Look at every event in the queue
    for event in pygame.event.get():
        # Did the user hit a key?
        if event.type == KEYDOWN:
            # Was it the Escape key? If so, stop the loop.
            if event.key == K_ESCAPE:
                running = False

        # Did the user click the window close button? If so, stop the loop.
        elif event.type == QUIT:
            running = False

    # Get the set of keys pressed and check for user input
    pressed_keys = pygame.key.get_pressed()

    # Update the player sprite based on user keypresses
    player.update(pressed_keys)

    # Move the ball
    ball.update(pressed_keys)

            
    # Fill the screen with black
    screen.fill((0, 0, 0))

    # Draw the player on the screen
    screen.blit(player.surf, player.rect)

    # Draw the ball on the screen
    screen.blit(ball.surf, ball.rect)

    # Update the display
    pygame.display.flip()

pygame.display.quit()