大球吃小球

import pygame
import random
from math import sqrt
def rand_color():
    return  random.randint(0,255),random.randint(0,255),random.randint(0,255)

def crash(item1,item2):
    item1x,item1y = item1['pos']
    item2x,item2y = item2['pos']
    dx = item2x- item1x
    dy = item2y - item1y
    dist = int(sqrt(dx*dx+dy*dy))
    if dist<item1['r']+item2['r']:
        if item2['r']>item1['r']:
            item2['r']+=1
            if item1 in all_balls[:]:
                all_balls.remove(item1)
        else:
            item1['r']+=1
            if item2 in all_balls[:]:
                all_balls.remove(item2)

if __name__ == '__main__':
    pygame.init()
    screen = pygame.display.set_mode((600,600))
    screen.fill((123,123,20))
    pygame.display.flip()
    all_balls = []



    while True:
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                exit()
            if event.type == pygame.MOUSEBUTTONDOWN:

                ball ={
                    'r':random.randint(5,15),
                    'color':rand_color(),
                    'pos':event.pos,
                    'x_speed':random.randint(-3,3),
                    'y_speed':random.randint(-3,3)
                }
                all_balls.append(ball)
        screen.fill((123, 123, 20))
        for ball in all_balls:

            # pygame.time.wait(2)
            x,y = ball['pos']
            x+=ball['x_speed']
            y+=ball['y_speed']
            if x + ball['r'] >= 600 or x -ball['r'] <= 0:
                ball['x_speed'] *= -1
            if y + ball['r'] >= 600 or y - ball['r'] <= 0:
                ball['y_speed']*= -1

            ball['pos'] = x,y
            pygame.draw.circle(screen,ball['color'],(x,y),ball['r'])
        pygame.display.update()
        index = len(all_balls)
        for item1 in all_balls:
            for item2 in all_balls:
                if item1!=item2:
                    crash(item1,item2)