python写小球游戏-学习pygame模块

import pygame,sys,random

from pygame.locals import *
#定义文本函数
def print_text(font,x,y,text,color=(255,255,255)):
    imgText = font.render(text,True,color)
    screen.blit(imgText,(x,y))

#初始化参数
pygame.init()

screen = pygame.display.set_mode((600,500))#窗口大小
pygame.display.set_caption('接小球')#窗口标题，图标从哪里来的

font1 = pygame.font.Font(None,24)#默认字体 24号
pygame.mouse.set_visible(True)#窗口是否显示鼠标
white = 255,255,255
red = 220,50,50
yellow = 230,230,50
blue = 0,0,100
holl = 0
lives = 3
score = 0

game_over = True
mouse_x = mouse_y = 0
#初始化挡板位置
pos_x = 300
pos_y = 460
#小球的位置 水平方向随机，垂直方向降落
bomb_x = random.randint(0,500)
bomb_y = -50

vel_y = 0.7


while True:
    screen.fill(blue)
    for event in pygame.event.get():#从队列当中获得所有的事件
        if event.type == QUIT:
            sys.exit()
        elif event.type == MOUSEMOTION:#如果是鼠标的类型
            mouse_x,mouse_y = event.pos
        elif event.type == MOUSEBUTTONUP:#如果鼠标抬起，则定义开始的参数
            if game_over:
                game_over = False
                lives = 3
                score = 0
    keys = pygame.key.get_pressed()
    if keys[K_ESCAPE]:
        sys.exit()


    if game_over==True: #此处当前是FLSE，只见过默认是True的情况?这个老师讲错，本处是True
        print_text(font1,100,200,'CLICK TO PLAY')
    else:#如果没接到小球
        bomb_y += vel_y#程序中并没有用时间限制循环速度，那么速度快的电脑是不是更快一点？
        if bomb_y > 500:
            bomb_x = random.randint(0,500)
            bomb_y = -50
            lives -=1
            if lives == 0:
                game_over = True
        #如果接住小球
        elif bomb_y > pos_y:
            if bomb_x > pos_x and bomb_x < pos_x +120:
                score += 10
                bomb_x = random.randint(0,500)
                bomb_y = -50
        #绘制小球
        pygame.draw.circle(screen,yellow,(bomb_x,int(bomb_y)),30,0)
        pos_x = mouse_x
        if pos_x < 0:
            pos_x = 0
        elif pos_x > 500:
            pos_x = 500
        #画挡板
        pygame.draw.rect(screen,red,(pos_x,pos_y,120,40),0)#0是实心1是空心
    holl = holl+1
    print_text(font1,0,0,'LIVES:'+str(lives))
    print_text(font1,500,0,'SCORE:'+str(score))
    print_text(font1, 400, 0, 'HOLL:' + str(holl))
    pygame.display.update()