Pong.py

"""Created by Antoine Rebelo in November 2019.
    Single-file remake of Pong.
    -------------AntoPong V1.2-----------"""
import pygame

# Define constants and colours
BLACK = (0, 0, 0)
WHITE = (255, 255, 255)
RED = (255, 0, 0)
SCREENSIZE = (600, 350)
CENTER_RESET = (300, 250)
LEFT_PADDLE_POSITION = (75, 175)
RIGHT_PADDLE_POSITION = (525, 175)
LEFT_TEXT_POSITION = (125, 50)
RIGHT_TEXT_POSITION = (475, 50)
WELCOME_TEXT_POSITION = (300, 100)

# Initialise Pygame, set up the window and running conditions
pygame.init()
screen = pygame.display.set_mode(SCREENSIZE)
win = screen.get_rect()
pygame.display.set_caption("Pong")
pygame.key.set_repeat(10, 0)
fps = pygame.time.Clock()
font = pygame.font.Font('freesansbold.ttf', 18)

# Create ball and player objects.
ball = pygame.Rect(0, 0, 10, 10)
player1 = pygame.Rect(0, 0, 10, 50)
player2 = pygame.Rect.copy(player1)

# Initialise player score to 0
p1score = 0
p2score = 0

# Movement vector for the ball.
# Vertical and horizontal movement, and pixels per tick.
VEC = [3, 3]

# Initialise position of ball and player objects
player2.center = RIGHT_PADDLE_POSITION
player1.center = LEFT_PADDLE_POSITION
ball.center = CENTER_RESET


def resetPositions():
    """Resets position of all game objects after a goal is scored"""
    player2.center = RIGHT_PADDLE_POSITION
    player1.center = LEFT_PADDLE_POSITION
    ball.center = CENTER_RESET
    pygame.time.delay(500)


def drawObjects(p1score, p2score):
    """Draws all game objects on a black screen, and fixes FPS to 60"""
    # Clear the screen to black
    screen.fill(BLACK)

    # Initialise text and update player scores
    welcomeText = font.render("Best of 3 wins the game. Good luck", True, WHITE)
    p1ScoreText = font.render("W+S KEYS. Score: " + str(p1score), True, RED)
    p2ScoreText = font.render("UP-DOWN KEYS. Score: " + str(p2score), True, RED)
    welcomeBox = welcomeText.get_rect()
    p1Box = p1ScoreText.get_rect()
    p2Box = p2ScoreText.get_rect()
    welcomeBox.center = WELCOME_TEXT_POSITION
    p1Box.center = LEFT_TEXT_POSITION
    p2Box.center = RIGHT_TEXT_POSITION

    # Draw player, ball, and text objects onto the screen
    pygame.draw.rect(screen, WHITE, player1)
    pygame.draw.rect(screen, WHITE, player2)
    pygame.draw.rect(screen, WHITE, ball)
    screen.blit(p1ScoreText, p1Box)
    screen.blit(p2ScoreText, p2Box)
    screen.blit(welcomeText, welcomeBox)
    pygame.display.flip()
    fps.tick(60)


def movePlayers(keys):

    """Takes a key-event as parameter and assigns it an action in-game.
        Controls movement of player paddles and exiting out of the game."""
    global player1
    global player2

    # Amount of pixels the players move every tick
    step = 2
    
    # Key handling for player 2
    if keys[pygame.K_UP]:
        player2 = player2.move(0, -step)
    if keys[pygame.K_DOWN]:
        player2 = player2.move(0, +step)
    
    # Key handling for player 1
    if keys[pygame.K_w]:
        player1 = player1.move(0, -step)
    if keys[pygame.K_s]:
        player1 = player1.move(0, +step)
    if keys[pygame.K_ESCAPE]:
        exit()

def moveBall():
    global ball, p1score, p2score
    
# Movement of the ball using the vector
    ball = ball.move(VEC)

    # Increment score after goal and change direction on kickoff after reset
    if ball.left < 0:
        p2score = p2score - -1
        VEC[0] = -VEC[0]
        resetPositions()

    if ball.right > win.right:
        p1score = p1score - -1
        VEC[0] = -VEC[0]
        resetPositions()

    # Ball bouncing mechanics
    if ball.top < 0 or ball.bottom > win.bottom:
        VEC[1] = -VEC[1]
    if player2.colliderect(ball) or player1.colliderect(ball):
        VEC[0] = -VEC[0]

def main():
    """Main game loop. Specifies ball physics and controls movement of all in-game.
        Controls game logic and updates player scores accordingly."""

    # Start of game loop
    while True:
        for event in pygame.event.get():
            if event.type == pygame.QUIT or p1score == 3 or p2score == 3:
                exit()
            keysPressed = pygame.key.get_pressed()
            movePlayers(keysPressed)
        moveBall()
        drawObjects(p1score, p2score)


if __name__ == "__main__":
    main()