Question

I have coded an animation (in python) for a beach ball to bounce around a screen. I now wish to add a second ball to the window, and when the two collide for them to bounce off each other.

So far, my attempts at this have been unsuccessful. Any ideas how to do this? The code I have so far is below.

import pygame  import sys  if __name__ =='__main__':      ball_image = 'Beachball.jpg'     bounce_sound = 'Thump.wav'     width = 800     height = 600     background_colour = 0,0,0     caption= 'Bouncing Ball animation'     velocity = [1,1]     pygame.init ()     frame = pygame.display.set_mode ((width, height))     pygame.display.set_caption (caption)     ball= pygame.image.load (ball_image). convert()     ball_boundary = ball.get_rect (center=(300,300))     sound = pygame.mixer.Sound (bounce_sound)     while True:         for event in pygame.event.get():             print event              if event.type == pygame.QUIT: sys.exit(0)         if ball_boundary.left < 0 or ball_boundary.right > width:             sound.play()             velocity[0] = -1 * velocity[0]         if ball_boundary.top < 0 or ball_boundary.bottom > height:             sound.play()             velocity[1] = -1 * velocity[1]          ball_boundary = ball_boundary.move (velocity)         frame.fill (background_colour)         frame.blit (ball, ball_boundary)         pygame.display.flip() 

Answer 1

Here’s a very basic restructure of your code. It could still be tidied up a lot, but it should show you how you can use instances of the class.

import pygame import random import sys  class Ball:     def __init__(self,X,Y):         self.velocity = [1,1]         self.ball_image = pygame.image.load ('Beachball.jpg'). convert()         self.ball_boundary = self.ball_image.get_rect (center=(X,Y))         self.sound = pygame.mixer.Sound ('Thump.wav')  if __name__ =='__main__':     width = 800     height = 600     background_colour = 0,0,0     pygame.init()     frame = pygame.display.set_mode((width, height))     pygame.display.set_caption('Bouncing Ball animation')     num_balls = 1000     ball_list = []     for i in range(num_balls):         ball_list.append( Ball(random.randint(0, width),random.randint(0, height)) )     while True:         for event in pygame.event.get():             print event              if event.type == pygame.QUIT:                 sys.exit(0)         frame.fill (background_colour)         for ball in ball_list:             if ball.ball_boundary.left < 0 or ball.ball_boundary.right > width:                 ball.sound.play()                 ball.velocity[0] = -1 * ball.velocity[0]             if ball.ball_boundary.top < 0 or ball.ball_boundary.bottom > height:                 ball.sound.play()                 ball.velocity[1] = -1 * ball.velocity[1]              ball.ball_boundary = ball.ball_boundary.move (ball.velocity)             frame.blit (ball.ball_image, ball.ball_boundary)         pygame.display.flip()