Pygame入门 2022 （4） 使用精灵类重构

前面3章已经完成了游戏，这章使用OOP风格重构游戏，然后给游戏添加一点音乐。

用精灵类重构

如果你完成了前3章的代码，应该会发现代码很乱。想更改某个代码？查找困难、修改起来更困难！不断添加的新功能让我们的代码越来越复杂，难以阅读。

考虑使用OOP重构代码，将游戏元素用类组织起来。Pygame提供了Sprite，便于我们控制游戏中的元素：

Sprite（精灵）类，可以看成是surface+rectangle的组合，并且绘制和更新起来非常容易。

想要绘制一个精灵，只需要：1.创建sprite;2.将sprite放到Group或GroupSingle中;3.通过group进行 draw/update （和把大象放进冰箱里一样简单）

Group，是用于装精灵的容器。GroupSingle，只能装一个精灵。

下面，我们用精灵重构玩家的属性和方法：继承精灵类，并重写其方法。__init__(self)在初始化方法中，初始化素材，初始image和rect。注意，这里image和rect是固定写法，Sprite更新时会用到这两个名称。另外初始化方法中要调用父类的初始化方法。

update(self):角色更新的逻辑。

class Player(pygame.sprite.Sprite): def __init__(self): super().__init__() walk_1 = pygame.image.load('graphics/Player/player_walk_1.png').convert_alpha() walk_2 = pygame.image.load('graphics/Player/player_walk_2.png').convert_alpha() self.walk = [walk_1, walk_2] self.index = 0 self.jump = pygame.image.load('graphics/Player/jump.png').convert_alpha() self.image = self.walk[self.index] self.rect = self.image.get_rect(midbottom=(80, 300)) self.gravity = 0 self.jump_sound = pygame.mixer.Sound('audio/jump.mp3') self.jump_sound.set_volume(0.5) def input(self): keys = pygame.key.get_pressed() if keys[pygame.K_SPACE] and self.rect.bottom >= 300: self.jump_sound.play() self.gravity -= 20 def apply_gravity(self): self.gravity += 1 self.rect.y += self.gravity if self.rect.bottom >= 300: self.rect.bottom = 300 self.gravity = 0 def animation_state(self): if self.rect.bottom < 300: self.image = self.jump else: self.index += 0.1 if self.index >= len(self.walk): self.index = 0 self.image = self.walk[int(self.index)] def update(self): self.input() self.apply_gravity() self.animation_state()

然后需要将其放到Group/GroupSingle中：

player = pygame.sprite.GroupSingle() player.add(Player())

最后在游戏的主循环中，调用Group的draw和update方法。

player.draw(screen) player.update()

类似地，可以创建蜗牛和苍蝇。它们都是一种障碍，可以创建一个类Obstacle来表示。然后放到Group中：

obstacle_group = pygame.sprite.Group() ... if event.type == obstacle_timer: obstacle_group.add(Obstacle(random.choice(['fly', 'snail', 'snail', 'snail'])))

在游戏的主循环中，调用Group的draw和update方法。

obstacle_group.draw(screen) obstacle_group.update()

使用精灵后，检测它们之间的碰撞很简单，只需要使用pygame.sprite中的碰撞检测即可：

def collision_sprite(): if pygame.sprite.spritecollide(player.sprite, obstacle_group, False): obstacle_group.empty() return False return True

添加音乐

播放音乐相当简单，加载、播放。这里我们播放一个背景音乐。

bg_music = pygame.mixer.Sound('audio/张震岳 - 迷途羔羊.mp3') bg_music.set_volume(0.5) # 设置音量50% bg_music.play(loops=-1) # loops为播放重复的次数，-1 表示永远循环播放。

可以在玩家跳跃时添加一个音效。

# in __init__() self.jump_sound = pygame.mixer.Sound('audio/jump.mp3') # in input() if keys[pygame.K_SPACE] and self.rect.bottom >= 300: self.jump_sound.play()

完整代码：

import random import pygame from sys import exit class Player(pygame.sprite.Sprite): def __init__(self): super().__init__() walk_1 = pygame.image.load('graphics/Player/player_walk_1.png').convert_alpha() walk_2 = pygame.image.load('graphics/Player/player_walk_2.png').convert_alpha() self.walk = [walk_1, walk_2] self.index = 0 self.jump = pygame.image.load('graphics/Player/jump.png').convert_alpha() self.image = self.walk[self.index] self.rect = self.image.get_rect(midbottom=(80, 300)) self.gravity = 0 self.jump_sound = pygame.mixer.Sound('audio/jump.mp3') self.jump_sound.set_volume(0.5) def input(self): keys = pygame.key.get_pressed() if keys[pygame.K_SPACE] and self.rect.bottom >= 300: self.jump_sound.play() self.gravity -= 20 def apply_gravity(self): self.gravity += 1 self.rect.y += self.gravity if self.rect.bottom >= 300: self.rect.bottom = 300 self.gravity = 0 def animation_state(self): if self.rect.bottom < 300: self.image = self.jump else: self.index += 0.1 if self.index >= len(self.walk): self.index = 0 self.image = self.walk[int(self.index)] def update(self): self.input() self.apply_gravity() self.animation_state() class Obstacle(pygame.sprite.Sprite): def __init__(self, type): super().__init__() if type == 'fly': fly_frame_1 = pygame.image.load('graphics/Fly/Fly1.png').convert_alpha() fly_frame_2 = pygame.image.load('graphics/Fly/Fly2.png').convert_alpha() self.frames = [fly_frame_1, fly_frame_2] y_pos = 210 elif type == 'snail': snail_frame_1 = pygame.image.load('graphics/snail/snail1.png').convert_alpha() snail_frame_2 = pygame.image.load('graphics/snail/snail2.png').convert_alpha() self.frames = [snail_frame_1, snail_frame_2] y_pos = 300 self.index = 0 self.image = self.frames[self.index] self.rect = self.image.get_rect(midbottom=(random.randint(900, 1100), y_pos)) def animation_state(self): self.index += 0.1 if self.index >= len(self.frames): self.index = 0 self.image = self.frames[int(self.index)] def update(self): self.animation_state() self.rect.x -= 6 self.destroy() def destroy(self): if self.rect.x <= -100: self.kill() def display_score(): # 显示分数 current = pygame.time.get_ticks() // 1000 - start_time score_surf = test_font.render(f"Score:{current}", False, (64, 64, 64)) screen.blit(score_surf, score_surf.get_rect(center=(400, 50))) return current def collision_sprite(): if pygame.sprite.spritecollide(player.sprite, obstacle_group, False): obstacle_group.empty() return False return True # 初始化 引擎 pygame.init() # 设置屏幕 screen = pygame.display.set_mode((800, 400)) # 宽度800，高度400 pygame.display.set_caption('Runner') # 设置标题 # 时钟 clock = pygame.time.Clock() # 字体 test_font = pygame.font.Font('font/Pixeltype.ttf', 50) # 背景 sky_surf = pygame.image.load('graphics/Sky.png').convert() ground_surf = pygame.image.load('graphics/ground.png').convert() # 得分 score_surf = test_font.render("My game", False, 'Black') score_rect = score_surf.get_rect(center=(400, 50)) # 游戏简介 game_name_surf = test_font.render("Runner", False, 'Black') game_name_rect = game_name_surf.get_rect(center=(400, 80)) game_message_surf = test_font.render("Press space to run", False, (111, 196, 169)) game_message_rect = game_message_surf.get_rect(center=(400, 320)) # 人物画 player_stand_surf = pygame.image.load('graphics/Player/player_stand.png').convert_alpha() player_stand_surf = pygame.transform.rotozoom(player_stand_surf, 0, 2) player_stand_rect = player_stand_surf.get_rect(midbottom=(400, 300)) # Timer obstacle_timer = pygame.USEREVENT + 1 pygame.time.set_timer(obstacle_timer, 800) player = pygame.sprite.GroupSingle() player.add(Player()) obstacle_group = pygame.sprite.Group() bg_music = pygame.mixer.Sound('audio/张震岳 - 迷途羔羊.mp3') bg_music.set_volume(0.5) bg_music.play(loops=-1) start_time = 0 score = 0 game_activate = False while True: # 获取用户输入 for event in pygame.event.get(): # 用户点击退出，关闭游戏 if event.type == pygame.QUIT: pygame.quit() exit() if game_activate: if event.type == obstacle_timer: obstacle_group.add(Obstacle(random.choice(['fly', 'snail', 'snail', 'snail']))) else: if event.type == pygame.KEYDOWN and event.key == pygame.K_SPACE: game_activate = True start_time = pygame.time.get_ticks() // 1000 # 游戏运行：绘图,更新 if game_activate: pygame.draw.rect(screen, '#c0e8ec', score_rect) pygame.draw.rect(screen, '#c0e8ec', score_rect, 10) screen.blit(sky_surf, (0, 0)) # 将test_surface放到screen上。(0,0)：放置后test_surface的左上角位于screen的(0,0)处 screen.blit(ground_surf, (0, 300)) score = display_score() player.draw(screen) player.update() obstacle_group.draw(screen) obstacle_group.update() game_activate = collision_sprite() # 游戏结束： else: screen.fill((94, 129, 162)) screen.blit(player_stand_surf, player_stand_rect) screen.blit(game_name_surf, game_name_rect) if score == 0: screen.blit(game_message_surf, game_message_rect) else: score_message = test_font.render(f'Your score:{score}', False, (111, 196, 169)) score_message_rect = score_message.get_rect(center=(400, 320)) screen.blit(score_message, score_message_rect) pygame.display.update() clock.tick(60) # 不超过60 fps