Destello y suma

Parte de la sección Sonido y sensaciones del juego del Journey de Pygame de Coddy. Lección 23 de 23.

Dos últimos retoques. Cuando el jugador pierde una vida, toda la pantalla parpadea en rojo por un momento, para que la pérdida no pase desapercibida. Cuando obtiene puntos, el número aumenta progresivamente en lugar de saltar.

El destello rojo es una Surface del tamaño de la ventana, rellenada de rojo y hecha transparente con set_alpha(), desde 0 (invisible) hasta 255 (opaca). Créala una vez, antes del bucle:

red = pygame.Surface((640, 480))
red.fill((255, 0, 0))
red.set_alpha(90)

Al perder una vida, se establece flash = 12. Cada fotograma lo reduce, y mientras sea mayor que 0, el juego dibuja red sobre el mundo, antes del texto.

Para la puntuación, conserva un segundo número, shown_score, y acércalo progresivamente al valor real en cada fotograma:

shown_score += (score - shown_score) * 0.2

Dibuja round(shown_score). El juego sigue decidiendo todo con score; solo la visualización se suaviza. Esa es la regla para todos los retoques de este capítulo: cambian lo que el jugador ve y oye, nunca las reglas.

Desafío

Intermedio

Antes del bucle: flash = 0, la superficie roja con alfa 90 y shown_score = 0.
Establece flash = 12 en ambos lugares donde se pierde una vida.
Junto a explosions.update(): reduce flash en 1 mientras sea mayor que 0 y acerca gradualmente shown_score a score en 0.2.
Después de dibujar el mundo, dibuja red en (0, 0) mientras flash sea mayor que 0.
Muestra Score: {round(shown_score)} en lugar de la puntuación.

Pruébalo tú mismo

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 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),
        })


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()
world = pygame.Surface((640, 480))
particles = []
shake = 0
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()
            burst(enemy.rect.center)
            shake = min(shake + 6, 15)
            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))
            burst(enemy.rect.center)
            shake = 15
        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()
    for p in particles:
        p["x"] += p["vx"]
        p["y"] += p["vy"]
        p["life"] -= 1
    particles = [p for p in particles if p["life"] > 0]

    world.fill((12, 14, 30))
    enemies.draw(world)
    lasers.draw(world)
    world.blit(player.image, player.rect)
    explosions.draw(world)
    for p in particles:
        pygame.draw.circle(world, (255, 170, 60), (p["x"], p["y"]), p["life"] // 10 + 1)

    offset = (0, 0)
    if shake > 0:
        amount = shake // 3
        offset = (random.randint(-amount, amount), random.randint(-amount, amount))
        shake -= 1
    screen.fill((0, 0, 0))
    screen.blit(world, offset)
    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()