Waves and Victory

Part of the Sprites and Images section of Coddy's Pygame journey. Lesson 36 of 36.

The last piece: more waves, each harder, and a way to win. Describe the waves as data, one tuple per wave: its picture, how many enemies, their speed.

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

wave is the index of the wave being played. Start the first with image, count, speed = WAVES[wave], which unpacks the tuple into three names, then spawn_wave(image, count, speed). When enemies is empty, the wave is cleared:

if not enemies:
    wave += 1
    if wave < len(WAVES):
        image, count, speed = WAVES[wave]
        spawn_wave(image, count, speed)

Once wave reaches len(WAVES), every wave is done: the player wins. Stop the game then too, with if lives > 0 and wave < len(WAVES):, and show You win!. A fourth wave is one more tuple in the list.

Challenge

Medium

Load enemy_green.png and enemy_yellow.png, and make the WAVES list above.
Make wave = 0 and start the first wave from WAVES.
When enemies is empty, move to the next wave and spawn it, if there is one.
Update only while lives > 0 and wave < len(WAVES).
While playing, show Wave and wave + 1 with its top middle at (320, 10). After the last wave, show You win! centred at (320, 240), unless it is Game over.

Try it yourself

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()
explosion_frames = []
for number in range(1, 5):
    explosion_frames.append(pygame.image.load(f"assets/images/explosion_{number}.png").convert_alpha())


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 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
spawn_wave(red_image, 6, 2)

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

    if lives > 0:
        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
        lasers.update()
        enemies.update()
        for enemy in enemies:
            if enemy.rect.top > 480:
                enemy.kill()
                lives -= 1
        hits = pygame.sprite.groupcollide(enemies, lasers, True, True, pygame.sprite.collide_mask)
        for enemy in hits:
            score += 10
            explosions.add(Explosion(enemy.rect.center))
        crashes = pygame.sprite.spritecollide(player, enemies, True, pygame.sprite.collide_mask)
        for enemy in crashes:
            lives -= 1
            explosions.add(Explosion(enemy.rect.center))
    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 lives <= 0:
        message = font.render("Game over", True, (240, 240, 240))
        screen.blit(message, message.get_rect(center=(320, 240)))
    pygame.display.flip()
    clock.tick(60)

pygame.quit()