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。
挑战
中等让每次爆炸都迸出火花。
- 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)。 - 在敌人爆炸的位置调用
burst(enemy.rect.center)。 - 在
explosions.update()旁边,移动粒子、减少其寿命,并移除消失的粒子。 - 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()
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