Simple Space Invaders using Python and PyGame

gistfile1.txt

import pygame
import random
import math
import os

# Initialize
pygame.init()
WIDTH, HEIGHT = 800, 600
screen = pygame.display.set_mode((WIDTH, HEIGHT))
pygame.display.set_caption("Space Invaders")

# Assets folder
ASSETS = "assets"

# Load images
player_img = pygame.image.load(os.path.join(ASSETS, "player.png"))
enemy_img = pygame.image.load(os.path.join(ASSETS, "enemy.png"))
bullet_img = pygame.image.load(os.path.join(ASSETS, "bullet.png"))
enemy_bullet_img = pygame.image.load(os.path.join(ASSETS, "enemy_bullet.png"))
explosion_imgs = [pygame.image.load(os.path.join(ASSETS, f"explosion{i}.png")) for i in range(1, 5)]

# Load sounds
shoot_sound = pygame.mixer.Sound(os.path.join(ASSETS, "shoot.wav"))
explosion_sound = pygame.mixer.Sound(os.path.join(ASSETS, "explosion.wav"))
game_over_sound = pygame.mixer.Sound(os.path.join(ASSETS, "gameover.wav"))

# Colors
WHITE = (255, 255, 255)
background_color = (10, 10, 30)
font = pygame.font.SysFont("consolas", 28)

# Game Variables
player_x = 370
player_y = 500
player_speed = 5

bullet_x = 0
bullet_y = player_y
bullet_speed = 7
bullet_state = "ready"

score = 0
level = 1
lives = 3
enemy_rows = 3
enemy_cols = 6

enemy_bullets = []
enemy_bullet_speed = 4
enemy_fire_delay = 50  # Lower = more frequent

# Enemies
def spawn_enemies(rows):
    enemies = []
    for row in range(rows):
        for col in range(enemy_cols):
            x = 100 + col * 80
            y = 50 + row * 60
            enemy = {"x": x, "y": y, "x_change": 2, "y_change": 40, "alive": True}
            enemies.append(enemy)
    return enemies

enemies = spawn_enemies(enemy_rows)

# Explosion animation
explosions = []

def show_explosion(x, y):
    explosions.append({"x": x, "y": y, "frame": 0})

def draw_explosions():
    for e in explosions[:]:
        screen.blit(explosion_imgs[e["frame"] // 5], (e["x"], e["y"]))
        e["frame"] += 1
        if e["frame"] >= 20:
            explosions.remove(e)

# Helper Functions
def is_collision(x1, y1, x2, y2, threshold=27):
    return math.hypot(x2 - x1, y2 - y1) < threshold

def fire_bullet():
    global bullet_state, bullet_x, bullet_y
    bullet_state = "fire"
    bullet_x = player_x
    bullet_y = player_y
    shoot_sound.play()

def draw_enemies():
    for enemy in enemies:
        if enemy["alive"]:
            screen.blit(enemy_img, (enemy["x"], enemy["y"]))

def fire_enemy_bullet(enemy):
    if random.randint(0, enemy_fire_delay) == 0:
        bullet = {"x": enemy["x"] + 24, "y": enemy["y"] + 32}
        enemy_bullets.append(bullet)

def game_over():
    game_over_sound.play()
    msg = font.render("GAME OVER", True, WHITE)
    screen.blit(msg, (WIDTH//2 - 100, HEIGHT//2 - 20))
    pygame.display.update()
    pygame.time.wait(3000)
    pygame.quit()
    exit()

# Main loop
clock = pygame.time.Clock()
running = True

while running:
    screen.fill(background_color)
    clock.tick(60)

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

    # Keypress
    keys = pygame.key.get_pressed()
    if keys[pygame.K_LEFT]:
        player_x -= player_speed
    if keys[pygame.K_RIGHT]:
        player_x += player_speed
    if keys[pygame.K_SPACE] and bullet_state == "ready":
        fire_bullet()

    # Player bounds
    player_x = max(0, min(player_x, WIDTH - 64))

    # Bullet movement
    if bullet_state == "fire":
        screen.blit(bullet_img, (bullet_x + 16, bullet_y))
        bullet_y -= bullet_speed
        if bullet_y <= 0:
            bullet_state = "ready"

    # Enemy logic
    enemy_direction_change = False
    for enemy in enemies:
        if enemy["alive"]:
            enemy["x"] += enemy["x_change"]
            if enemy["x"] <= 0 or enemy["x"] >= WIDTH - 64:
                enemy["x_change"] *= -1
                enemy_direction_change = True

            fire_enemy_bullet(enemy)

            # Collision with bullet
            if bullet_state == "fire" and is_collision(bullet_x, bullet_y, enemy["x"], enemy["y"]):
                enemy["alive"] = False
                show_explosion(enemy["x"], enemy["y"])
                explosion_sound.play()
                score += 10
                bullet_state = "ready"

            # Check game over condition
            if enemy["y"] > player_y - 40:
                game_over()

    if enemy_direction_change:
        for enemy in enemies:
            enemy["y"] += enemy["y_change"]

    # Enemy bullets
    for eb in enemy_bullets[:]:
        screen.blit(enemy_bullet_img, (eb["x"], eb["y"]))
        eb["y"] += enemy_bullet_speed
        if eb["y"] > HEIGHT:
            enemy_bullets.remove(eb)
        elif is_collision(eb["x"], eb["y"], player_x, player_y, 30):
            show_explosion(player_x, player_y)
            explosion_sound.play()
            enemy_bullets.remove(eb)
            lives -= 1
            if lives <= 0:
                game_over()

    # Level progression
    if all(not e["alive"] for e in enemies):
        level += 1
        enemy_rows += 1
        enemy_fire_delay = max(10, enemy_fire_delay - 5)
        enemies = spawn_enemies(enemy_rows)

    # Draw player and enemies
    screen.blit(player_img, (player_x, player_y))
    draw_enemies()
    draw_explosions()

    # Score and lives
    score_text = font.render(f"Score: {score}  Lives: {lives}  Level: {level}", True, WHITE)
    screen.blit(score_text, (10, 10))

    pygame.display.update()