Menu
CoddyTech

每次命中都迸出火花

本课属于 Coddy Pygame 学习旅程的“音效与游戏体验”单元。第 21 课,共 23 课。

敌人爆炸时,效果也要像爆炸。从火花开始:在敌人所在的位置喷出一团粒子。

两种情况下都会出现爆炸,一种是被激光击中,另一种是发生碰撞,所以把爆炸效果放进一个函数里:

def burst(center):
    for i in range(16):
        particles.append({"x": center[0], "y": center[1],
                          "vx": random.uniform(-4, 4), "vy": random.uniform(-4, 4),
                          "life": random.randint(15, 30)})

这个函数只负责生成火花。每一帧都要移动火花,这和“粒子”一章中的做法一样:移动每个火花,减少它的生命值,并且只保留还存活的火花。

在 explosions.update() 旁边执行这些操作,放在 if lives > 0 ... 外面。结束游戏的碰撞也会产生爆炸效果,即使游戏结束,火花也应该继续向外飞散。在爆炸效果之后绘制火花,这样它们就会显示在上层。

challenge icon

挑战

中等

让每次爆炸都迸出火花。

  1. 创建 particles = [],以及 burst(center):在 center 处生成 16 个粒子,vx 和 vy 的值取自 random.uniform(-4, 4),life 的值取自 random.randint(15, 30)。
  2. 在敌人爆炸的位置调用 burst(enemy.rect.center)。
  3. 在 explosions.update() 旁边,移动粒子、减少其寿命,并移除消失的粒子。
  4. 将粒子绘制成橙色 (255, 170, 60),半径为 life // 10 + 1。

按下“开始”并射击一个敌人:橙色火花就会迸出。然后点击“检查”。

亲手试试

import random
import pygame

pygame.init()
screen = pygame.display.set_mode((640, 480))
pygame.display.set_caption("Star Patrol")
clock = pygame.time.Clock()
font = pygame.font.Font(None, 32)

ship_image = pygame.image.load("assets/images/ship.png").convert_alpha()
laser_image = pygame.image.load("assets/images/laser.png").convert_alpha()
red_image = pygame.image.load("assets/images/enemy_red.png").convert_alpha()
green_image = pygame.image.load("assets/images/enemy_green.png").convert_alpha()
yellow_image = pygame.image.load("assets/images/enemy_yellow.png").convert_alpha()
explosion_frames = []
for number in range(1, 5):
    explosion_frames.append(pygame.image.load(f"assets/images/explosion_{number}.png").convert_alpha())

laser_sound = pygame.mixer.Sound("assets/sounds/laser.ogg")
laser_sound.set_volume(0.4)
explosion_sound = pygame.mixer.Sound("assets/sounds/explosion.ogg")
hit_sound = pygame.mixer.Sound("assets/sounds/hit.ogg")

WAVES = [(red_image, 6, 2), (green_image, 8, 2), (yellow_image, 10, 3)]


class Player(pygame.sprite.Sprite):
    def __init__(self):
        super().__init__()
        self.image = ship_image
        self.rect = self.image.get_rect(midbottom=(320, 470))
        self.mask = pygame.mask.from_surface(self.image)

    def update(self):
        keys = pygame.key.get_pressed()
        if keys[pygame.K_LEFT]:
            self.rect.x -= 6
        if keys[pygame.K_RIGHT]:
            self.rect.x += 6
        self.rect.clamp_ip(screen.get_rect())


class Laser(pygame.sprite.Sprite):
    def __init__(self, x, y):
        super().__init__()
        self.image = laser_image
        self.rect = self.image.get_rect(midbottom=(x, y))
        self.mask = pygame.mask.from_surface(self.image)

    def update(self):
        self.rect.y -= 10
        if self.rect.bottom < 0:
            self.kill()


class Enemy(pygame.sprite.Sprite):
    def __init__(self, image, x, y, speed):
        super().__init__()
        self.image = image
        self.rect = self.image.get_rect(center=(x, y))
        self.mask = pygame.mask.from_surface(self.image)
        self.speed = speed

    def update(self):
        self.rect.y += self.speed


class Explosion(pygame.sprite.Sprite):
    def __init__(self, center):
        super().__init__()
        self.index = 0
        self.timer = 0
        self.image = explosion_frames[0]
        self.rect = self.image.get_rect(center=center)

    def update(self):
        self.timer += 1
        if self.timer == 5:
            self.timer = 0
            self.index += 1
            if self.index == len(explosion_frames):
                self.kill()
            else:
                self.image = explosion_frames[self.index]


def play_music(path, loops=-1):
    pygame.mixer.music.load(path)
    pygame.mixer.music.play(loops)


def spawn_wave(image, count, speed):
    for i in range(count):
        x = random.randint(40, 600)
        enemies.add(Enemy(image, x, -40 - i * 120, speed))


player = Player()
lasers = pygame.sprite.Group()
enemies = pygame.sprite.Group()
explosions = pygame.sprite.Group()
last_shot = 0
score = 0
lives = 3
wave = 0
image, count, speed = WAVES[wave]
spawn_wave(image, count, speed)
pygame.mixer.music.set_volume(0.5)
play_music("assets/music/level.ogg")

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

    if lives > 0 and wave < len(WAVES):
        player.update()
        keys = pygame.key.get_pressed()
        now = pygame.time.get_ticks()
        if keys[pygame.K_SPACE] and now - last_shot >= 250:
            lasers.add(Laser(player.rect.centerx, player.rect.top))
            last_shot = now
            laser_sound.play()
        lasers.update()
        enemies.update()
        for enemy in enemies:
            if enemy.rect.top > 480:
                enemy.kill()
                lives -= 1
                hit_sound.play()
        hits = pygame.sprite.groupcollide(enemies, lasers, True, True, pygame.sprite.collide_mask)
        for enemy in hits:
            score += 10
            explosion_sound.play()
            explosions.add(Explosion(enemy.rect.center))
        crashes = pygame.sprite.spritecollide(player, enemies, True, pygame.sprite.collide_mask)
        for enemy in crashes:
            lives -= 1
            hit_sound.play()
            explosions.add(Explosion(enemy.rect.center))
        if not enemies:
            wave += 1
            if wave < len(WAVES):
                image, count, speed = WAVES[wave]
                spawn_wave(image, count, speed)
            else:
                play_music("assets/music/win.ogg", 0)
        if lives <= 0:
            play_music("assets/music/lose.ogg", 0)
    explosions.update()

    screen.fill((12, 14, 30))
    enemies.draw(screen)
    lasers.draw(screen)
    screen.blit(player.image, player.rect)
    explosions.draw(screen)
    score_text = font.render(f"Score: {score}", True, (240, 240, 240))
    screen.blit(score_text, (10, 10))
    lives_text = font.render(f"Lives: {max(lives, 0)}", True, (240, 240, 240))
    screen.blit(lives_text, lives_text.get_rect(topright=(630, 10)))
    if wave < len(WAVES):
        wave_text = font.render(f"Wave {wave + 1}", True, (240, 240, 240))
        screen.blit(wave_text, wave_text.get_rect(midtop=(320, 10)))
    if lives <= 0:
        message = font.render("Game over", True, (240, 240, 240))
        screen.blit(message, message.get_rect(center=(320, 240)))
    elif wave == len(WAVES):
        message = font.render("You win!", True, (240, 240, 240))
        screen.blit(message, message.get_rect(center=(320, 240)))
    pygame.display.flip()
    clock.tick(60)

pygame.quit()

音效与游戏体验中的所有课

自己练习: Pygame 在线编辑器