作业1：

"""__author__=xx"""
import pygame
from random import randint
from math import sqrt,fabs

# 写一个函数，判断两个球是否相遇
def is_ball_meet(ball_1, ball_2):
    x1, y1 = ball_1['pos']
    r1 = ball_1['r']
    x2, y2 = ball_2['pos']
    r2 = ball_2['r']
    if (r1 + r2) > sqrt((x1-x2)**2 + (y1-y2)**2):
        return True
    return False

if __name__ == '__main__':
    pygame.init()
    screen = pygame.display.set_mode((600, 400))
    screen.fill((254,254,254))
    pygame.display.flip()

    # all_balls中保存多个球
    # 每个球要保存：半径、圆心、颜色、x速度、y速度
    all_balls = []


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

            if event.type == pygame.MOUSEBUTTONDOWN:
                ball_dict1 = {'r':randint(10,30), 'pos':event.pos, 'color':(randint(1,255),randint(1,255),randint(1,255)), 'x_speed':randint(-5,5), 'y_speed':randint(-5,5)}
                all_balls.append(ball_dict1)


        # 刷新界面
        screen.fill((254,254,254))
        pygame.time.delay(100)

        for ball_dict in all_balls:

            # 取出球原来的x坐标和y坐标以及速度
            x,y = ball_dict['pos']
            x_speed = ball_dict['x_speed']
            y_speed = ball_dict['y_speed']
            x += x_speed
            y += y_speed
            r = ball_dict['r']

            if 2 * r > 400:
                print('游戏结束')
                exit()

            if x - r <= 0:
                x = r
                x_speed = int(fabs(x_speed))
            if x + r >= 600:
                x = 600 - r
                x_speed = -int(fabs(x_speed))
            if y - r <= 0:
                y = r
                y_speed = int(fabs(y_speed))
            if y + r >= 400:
                y = 400 - r
                y_speed = -int(fabs(y_speed))
            pygame.draw.circle(screen,ball_dict['color'],(x,y),r)
            # 更新球对应的坐标
            ball_dict['pos'] = x,y
            ball_dict['x_speed'] = x_speed
            ball_dict['y_speed'] = y_speed



        if (len(all_balls) > 1):
            all_balls1 = []
            for item in all_balls:
                all_balls1.append(item)
                for item1 in all_balls:
                    if item1 not in all_balls1:
                        if is_ball_meet(item, item1):
                            item['r'] += item1['r']
                            all_balls.remove(item1)

        # if (len(all_balls) > 1):
        #     index_list = []
        #     for index1 in range(len(all_balls)):
        #         for index2 in range(index1+1, len(all_balls)):
        #             if is_ball_meet(all_balls[index1], all_balls[index2]):
        #                 index_list.append(index1)
        #                 all_balls[index2]['r'] += all_balls[index1]['r']
        #     for index3 in index_list:
        #         del all_balls[index3]

        pygame.display.flip()