Python编程：从入门到实践，课后题14-2

import sys
import pygame
from pygame.sprite import Sprite
from pygame.sprite import Group
from time import sleep
import pygame.font

screen=pygame.display.set_mode((1200,700))
bg_color=(20,40,50)
target_speed=5
charactor_speed=7
bullet_speed=8
game_active=True
fail_times=0
pygame.init()
class Target(Sprite):
"""建立被射击的矩形目标"""
def __init__(self, screen):
super(Target, self).__init__()
self.screen = screen
self.width, self.height=50,150
self.screen_rect=self.screen.get_rect()
self.rect = pygame.Rect(0, 0, self.width, self.height)
self.rect.right=self.screen_rect.right
self.rect.centery = self.screen_rect.centery
self.target_color=(255, 255, 255)
self.y=float(self.rect.y)
self.moving_direction=1
def blitme(self):
self.screen.fill(self.target_color,self.rect)
def update(self):
self.y+=target_speed*self.moving_direction
self.rect.y=self.y
def check_boundaries(target):                                  #检查矩形撞击边界和改变移动方向
if target.rect.top<=target.screen_rect.top:
target.moving_direction=1
if target.rect.bottom>=target.screen_rect.bottom:
target.moving_direction=-1
class Charactor(Sprite):
"""建立可操纵的角色"""
def __init__(self, screen):
super(Charactor, self).__init__()
self.screen = screen
self.image=pygame.image.load('timg.bmp')
self.rect=self.image.get_rect()
self.screen_rect=self.screen.get_rect()
self.rect.left=self.screen_rect.left+5
self.rect.centery=self.screen_rect.centery
self.moving_up=False
self.moving_dowm=False
def blitme(self):
self.screen.blit(self.image,self.rect)
def update(self):
if self.moving_up and self.rect.top>=self.screen_rect.top:
self.rect.y-=charactor_speed
if self.moving_dowm and self.rect.bottom<=self.screen_rect.bottom:
self.rect.y+=charactor_speed
def centerer_charactor(self):
self.rect.centery=self.screen_rect.centery

def keyup_events(event,charactor):                   #按键抬起
if event.key==pygame.K_UP:
charactor.moving_up=False
if event.key==pygame.K_DOWN:
charactor.moving_dowm=False

def keydowm_events(event,charactor,bullets):         #按键落下
if event.key==pygame.K_UP:
charactor.moving_up=True
if event.key==pygame.K_DOWN:
charactor.moving_dowm=True
if event.key==pygame.K_SPACE:
bullet=Bullet(screen,charactor)
bullets.add(bullet)

def check_events(charactor,bullets,stats,play_button,targets):      #检查事件发生
for event in pygame.event.get():
if event.type==pygame.KEYDOWN:
keydowm_events(event,charactor,bullets)
elif event.type==pygame.KEYUP:
keyup_events(event,charactor)
elif event.type==pygame.QUIT:
sys.exit()
elif event.type==pygame.MOUSEBUTTONDOWN:
mouse_x,mouse_y=pygame.mouse.get_pos()
check_play_button(stats,play_button,mouse_x,mouse_y,charactor,bullets,targets)
def check_play_button(stats,play_button,mouse_x,mouse_y,charactor,bullets,targets): #检查开始按钮，并清零游戏
button_clicked=play_button.rect.collidepoint(mouse_x,mouse_y)
if button_clicked and not stats.game_active:
pygame.mouse.set_visible(False)
stats.game_active=True
bullets.empty()
targets.empty()
target=Target(screen)
targets.add(target)
global fail_times
fail_times=0
charactor.centerer_charactor()

class Bullet(Sprite):
"""建立子弹"""
def __init__(self, screen,charactor):
super(Bullet, self).__init__()
self.screen = screen
self.width,self.height=15,5
self.bullet_color=(70,200,200)
self.rect=pygame.Rect(0,0,self.width,self.height)
self.creat_bullet=False
self.screen_rect=self.screen.get_rect()
self.rect.left=charactor.rect.right
self.rect.centery=charactor.rect.centery
def blitme(self):
pygame.draw.rect(self.screen,self.bullet_color,self.rect)
def update(self):
self.rect.x+=bullet_speed

def bullet_target(targets,bullets,game_stat):           #检查子弹撞击矩形
for bullet in bullets:
collisions=pygame.sprite.groupcollide(targets,bullets,True, True)
if collisions:
game_stat.game_active=False
pygame.mouse.set_visible(True)

def check_fail(bullets,game_stat):                    #检查失败次数，大于3则失败
for bullet in bullets:
if bullet.rect.left>=bullet.screen_rect.right:
bullets.remove(bullet)
global fail_times
fail_times+=1
if fail_times>=3:
game_stat.game_active=False
pygame.mouse.set_visible(True)

class Game_stat():                              #游戏开始时是不活跃状态
def __init__(self):
self.game_active=False

class Button():
"""建立开始按钮"""
def __init__(self, screen,msg):
self.screen = screen
self.screen_rect=screen.get_rect()
self.width,self.height=200,50
self.button_color=(0,255,0)
self.text_color=(255,255,255)
self.font=pygame.font.SysFont(None, 48)
self.rect=pygame.Rect(0,0,self.width,self.height)
self.rect.center=self.screen_rect.center
self.prep_msg(msg)
def prep_msg(self,msg):
self.msg_image=self.font.render(msg,True,self.text_color,self.button_color)
self.msg_image_rect=self.msg_image.get_rect()
self.msg_image_rect.center=self.rect.center
def draw_button(self):
self.screen.fill(self.button_color,self.rect)
self.screen.blit(self.msg_image,self.msg_image_rect)

def run_game():
target=Target(screen)
targets=Group()
charactor=Charactor(screen)
bullets=Group()
targets.add(target)
stats=Game_stat()
play_button=Button(screen,"play")
while True:
check_events(charactor,bullets,stats,play_button,targets)
screen.fill(bg_color)
charactor.blitme()
if stats.game_active:
for bullet in bullets:
bullet.blitme()
for target in targets:
target.blitme()
check_boundaries(target)
targets.update()
charactor.update()
bullets.update()
bullet_target(targets,bullets,stats)
check_fail(bullets,stats)
for bullet in bullets.copy():
if bullet.rect.x>=bullet.screen_rect.right:
bullets.remove(bullet)
pygame.display.flip()
if not stats.game_active:
play_button.draw_button()
pygame.display.flip()

run_game()