Pygame小游戏练习三

@Python编程从入门到实践 Python项目练习

七、创建Passenger类

创建passenger.py文件，创建Passenger类，控制乘客属性和行为

# passenger.py
import pygame
from pygame.sprite import Sprite

class Passenger(Sprite):
    """表示单个乘客的类"""
    def __init__(self, ai_settings, screen):
        """初始乘客并设置其起始位置"""
        super(Passenger, self).__init__()
        self.screen = screen
        self.ai_settings = ai_settings

        #  加载乘客图像，并设置其rect属性
        self.images = [pygame.image.load('images/passenger{}.png'.format(i))
                                       for i in range(1, 9)]
        # self.rect = self.images[1].get_rect()

        # self.image = pygame.image.load('images/passenger1.bmp')
        self.image = pygame.transform.scale(self.images[0], (50, 50))
        self.image_squence = 0
        self.rect = self.image.get_rect()

        # 每个乘客最初都在屏幕左上角附近
        self.rect.x = self.rect.centerx - 20
        self.rect.y = self.rect.centery - 20

        # 存储乘客的准确位置
        self.x = float(self.rect.x)

    def blitme(self):
        """在指定位置绘制乘客"""
        self.image = pygame.transform.scale(self.images[self.image_squence], (50, 50))
        self.image_squence += 1
        if self.image_squence > 7:
            self.image_squence = 0

        self.screen.blit(self.image, self.rect)
        # self.image = self.images[1]

    def check_edges(self):
        """如果外星人位于屏幕边缘，就放回True"""
        screen_rect = self.screen.get_rect()
        if self.rect.right >= screen_rect.right:
            return True
        elif self.rect.left <= 0:
            return True

    def update(self):
        """向右或向左移动外星人"""
        self.x += (self.ai_settings.passenger_speed_factor *
                   self.ai_settings.fleet_direction)
        self.rect.x = self.x

八、创建game_stats类

创建game_stats.py，game_stats类用于跟踪游戏统计信息，记录飞机和乘客发生的碰撞

class GameStats():
    """跟踪游戏的统计信息"""
    def __init__(self, ai_settings):
        """初始化统计信息"""
        self.ai_settings = ai_settings
        self.reset_stats()
        self.game_active = True

    def reset_stats(self):
        """初始化在游戏运行期间可能变化的统计信息"""
        self.ships_left = self.ai_settings.ship_limit