gistfile1.py

import pygame
import random
pygame.init()

SCREEN_WIDTH = 400
SCREEN_HEIGHT = 400
SIZE = (SCREEN_WIDTH, SCREEN_HEIGHT)
SCREEN = pygame.display.set_mode(SIZE)
pygame.display.set_caption('Colour Birth')


class Ball (pygame.sprite.Sprite):

    def __init__(self, colour, width, height, x=0, y=0):
        pygame.sprite.Sprite.__init__(self)
        self.image = pygame.Surface([width, height])
        self.image.fill(colour)
        self.rect = self.image.get_rect()
        self.rect.x = random.randint(50, 200)
        self.rect.y = random.randint(50, 200)
        self.colour = colour
        self.count = 0

        self.screen_border()  # DOESNT FUCKING WORK
        self.collided = False

    def movement(self):
        directions = (-1, 1)
        self.rect.x += random.choice(directions)
        self.rect.y += random.choice(directions)

    def collision(self, colour, obj1, obj2=None, obj3=None, obj4=None):
        self.count = 0
        if pygame.sprite.collide_rect(self, obj1) and self.collided is False:
            c = Ball(colour, 20, 20, 50, 50)
            self.count += 1
            ball_list.add(c)
            self.collided = True
            if self.count > 1:
                ball_list.remove(c)

    def screen_border(self):
        """Making a border for the window, no sprites may pass through"""
        print "It works!"
        if self.rect.x >= SCREEN_WIDTH-20:
            self.rect.x = SCREEN_WIDTH-40
        if self.rect.x <= 0:
            self.rect.x = 20
        if self.rect.y >= SCREEN_HEIGHT-20:
            self.rect.y = SCREEN_HEIGHT-40
        if self.rect.y <= 0:
            self.rect.y = 20


ball_list = pygame.sprite.Group()

a = Ball([255, 0, 0], 20, 20)
b = Ball([0, 0, 255], 20, 20)
e = Ball([0, 255, 255], 20, 20)

ball_list.add(a, b, e)

clock = pygame.time.Clock()
done = False

while done is False:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            done = True
        #Event processing
        if event.type == pygame.MOUSEBUTTONDOWN:
            pass

    #game logic
    for ball in ball_list:
        ball.movement()
    a.collision([255, 0, 255], b)
    b.collision([0, 255, 0], e)
    e.collision([255, 255, 0], a)
    #a.screen_border()
    #b.screen_border()
    #e.screen_border()
    #drawing commands
    SCREEN.fill([255, 255, 255])
    ball_list.draw(SCREEN)

    pygame.display.flip()

    clock.tick(30)

pygame.quit()