Pong in Python and Pygame

Question

I'm new to programming. This is my first project where I tried to use object-oriented programming. I'm looking for all kinds of comments.

import pygame, sys
from pygame.locals import *
from random import choice, random
INDIAN_RED = (205, 92, 92)
DARK_SALMON = (233, 150, 122)
DIM_GRAY = (105, 105, 105)
BLACK = (0, 0, 0)
SCREEN_HEIGHT = 300
SCREEN_WIDTH = 400
DISPLAYSURF = pygame.display.set_mode((SCREEN_WIDTH, SCREEN_HEIGHT), 0)
PADDLE_HEIGHT = 50
PADDLE_WIDTH = 4
PADDLE_VEL = 7
# enum values
UP = "gora"
DOWN = "dol"
points_r = 0
points_l = 0
class Paddle:
 def __init__(self, x, y, clr, vel):
 self.x = x
 self.y = y
 self.height = PADDLE_HEIGHT
 self.width = PADDLE_WIDTH
 self.color = clr
 self.vel = vel
 self.is_moving = False
 self.direction = None
 def draw(self):
 leftx = self.x - self.width/2
 topy = self.y - self.height/2
 coords = pygame.Rect(leftx, topy, self.width, self.height)
 pygame.draw.rect(DISPLAYSURF, self.color, coords, 0)
 def move(self):
 if not self.is_moving:
 return
 if self.direction == UP and self.y - self.height/2 > 0:
 self.y -= self.vel 
 elif self.direction == DOWN and self.y + self.height/2 < SCREEN_HEIGHT:
 self.y += self.vel 
class Ball:
 def __init__(self, r, color, vel):
 self.r = r
 self.color = color
 self.vel = vel
 self.reset()
 def draw(self):
 radius = self.r
 pygame.draw.circle(DISPLAYSURF, self.color, (self.x, self.y), self.r)
 def move(self):
 self.x += self.velx
 self.y += self.vely
 if self.y - self.r < 0 or self.y + self.r > SCREEN_HEIGHT:
 self.vely = - self.vely
 if self.x - self.r < 0:
 if collide(paddle_l, self):
 self.velx = - self.velx
 else:
 self.reset()
 global points_r
 points_r += 1
 elif self.x + self.r > SCREEN_WIDTH:
 if collide(paddle_r, self):
 self.velx = - self.velx
 else:
 self.reset()
 global points_l
 points_l += 1
 def reset(self):
 self.velx = choice(range(self.vel//2, self.vel))
 self.vely = choice(range(self.vel//2, self.vel))
 if random() > 0.5:
 self.velx *= -1
 if random() > 0.5:
 self.vely *= -1
 self.x = SCREEN_WIDTH//2
 self.y = SCREEN_HEIGHT//2
def collide(paddle, ball):
 if abs(ball.y - paddle.y) < paddle.height/2 + ball.r:
 return True
 else:
 return False
def create_points_text():
 text = FONT.render(str(points_l) + " : " + str(points_r), 1, (0,0,0))
 textpos = text.get_rect()
 textpos.centerx = SCREEN_WIDTH/2
 textpos.centery = 15
 return (text, textpos)
pygame.init()
FPS = 30
fpsClock = pygame.time.Clock()
pygame.display.set_caption("Ping Pong IGF 2017")
FONT = pygame.font.Font(None, 30)
paddle_r = Paddle(SCREEN_WIDTH - PADDLE_WIDTH/2, SCREEN_HEIGHT/2, INDIAN_RED, PADDLE_VEL) #right paddle
paddle_l = Paddle(0 + PADDLE_WIDTH/2, SCREEN_HEIGHT/2, DARK_SALMON, PADDLE_VEL) #left paddle
ball = Ball(5, BLACK, 6)
while True: #main loop
 DISPLAYSURF.fill(DIM_GRAY)
 paddle_r.move()
 paddle_l.move()
 paddle_r.draw()
 paddle_l.draw()
 ball.draw()
 ball.move()
 text_to_draw, textpos_to_draw = create_points_text()
 DISPLAYSURF.blit(text_to_draw, textpos_to_draw)
 for event in pygame.event.get():
 if event.type == pygame.KEYDOWN:
 if event.key == pygame.K_UP:
 paddle_r.is_moving = True
 paddle_r.direction = UP
 elif event.key == pygame.K_DOWN:
 paddle_r.is_moving = True
 paddle_r.direction = DOWN
 if event.key == pygame.K_w:
 paddle_l.is_moving = True
 paddle_l.direction = UP
 elif event.key == pygame.K_s:
 paddle_l.is_moving = True
 paddle_l.direction = DOWN
 elif event.type == pygame.KEYUP:
 if event.key == pygame.K_UP:
 paddle_r.is_moving = False
 elif event.key == pygame.K_DOWN:
 paddle_r.is_moving = False
 if event.key == pygame.K_w:
 paddle_l.is_moving = False
 elif event.key == pygame.K_s:
 paddle_l.is_moving = False
 elif event.type == QUIT:
 pygame.quit()
 sys.exit()
 pygame.display.update()
 fpsClock.tick(FPS)

• Edward: Looks like a good beginner project! I'm sure you'll get some good reviews.

Answer 1

Generally looks pretty good. A few things stick out:

if abs(ball.y - paddle.y) < paddle.height/2 + ball.r:
 return True
else:
 return False

is clearer as just:

return abs(ball.y-paddle.y) < paddle.height/2 + ball.r

Also, lots of repetition is a code smell, and

 if event.type == pygame.KEYDOWN:
 if event.key == pygame.K_UP:
 paddle_r.is_moving = True
 paddle_r.direction = UP
 elif event.key == pygame.K_DOWN:
 paddle_r.is_moving = True
 paddle_r.direction = DOWN
 if event.key == pygame.K_w:
 paddle_l.is_moving = True
 paddle_l.direction = UP
 elif event.key == pygame.K_s:
 paddle_l.is_moving = True
 paddle_l.direction = DOWN

is the same as:

MOVEKEYS = { pygame.K_UP : (paddle_r, UP), 
 pygame.K_w : (paddle_l, UP),
 pygame.K_DOWN: (paddle_r, DOWN),
 pygame.K_s : (paddle_l, DOWN) }
if event.type == pygame.KEYDOWN and event.key in MOVEKEYS:
 paddle, direction = MOVEKEYS[event.key]
 paddle.is_moving = True
 paddle.direction = direction

Note: fewer if statements and a lot less repetition. It makes the KEY_UP block easier too:

elif event.type == pygame.KEYUP and event.key in MOVEKEYS:
 paddle, _ = MOVEKEYS[event.key]
 paddle.is_moving = False