main.py

"""The main module of the game"""

from pathlib import Path
import random
from typing import Tuple
import pygame
import sprites


# Constants to control gameplay and hardness
SCROLLING_SPEED = 2
INITIAL_HP = 160
HP_INCREMENT = 40
HP_PACK_PROB = 0.001
POWER_UP_PROB = 0.001
HIT_HP_DROP = 10
COLLIDE_HP_DROP = 20
IMG_DIR = Path(__file__).resolve().parent / 'img'
SOUND_DIR = Path(__file__).resolve().parent / 'sound'


# functions to create our resources
def load_image(name, colorkey=None, scale: Tuple[int, int] = None):
    """
    Search for image file with filename 'name' in the ./sound/ directory
    and try to load it as a sound object.
    """
    path = IMG_DIR / name
    try:
        image = pygame.image.load(str(path))
    except pygame.error:
        print("Cannot load image:", path)
        raise SystemExit(str(pygame.compat.geterror()))
    image = image.convert()
    if colorkey is not None:
        if colorkey == -1:
            colorkey = image.get_at((0, 0))
        image.set_colorkey(colorkey, pygame.RLEACCEL)
    if scale is not None:
        image = pygame.transform.scale(image, scale)
    return image, image.get_rect()


class NoneSound:
    """Dummy sound object for the case cannot import pygame mixer module"""
    def play(self):
        pass

    def set_volume(self, i: float):
        pass


def load_sound(name: str) -> pygame.mixer.Sound:
    """
    Search for sound file with filename 'name' in the ./sound/ directory
    and try to load it as a sound object.
    """
    if not pygame.mixer:
        return NoneSound()
    path = SOUND_DIR / name
    try:
        sound = pygame.mixer.Sound(str(path))
    except pygame.error as message:
        print('Cannot load sound:', name)
        raise SystemExit(message)
    return sound


def main():
    """This is the main function."""
    pygame.init()

    # Load background music
    if not pygame.mixer:
        print('Warning: Sound disabled')
    music = load_sound('Africa.wav')
    music.set_volume(0.05)

    # Create pygame display window
    screen = pygame.display.set_mode((480, 640))
    pygame.display.set_caption('pbc fly')

    # Load background image
    background, _ = load_image('background1.png', scale=(480, 640))
    background1_rect = pygame.Rect(0, 0, 480, 640)
    background2_rect = pygame.Rect(0, 0, 480, 640)

    # Set the font of the score
    score_font = pygame.font.SysFont('arial', 25)

    start_button = sprites.Button('start.png', 'start_down.png', (240, 320))
    again_button = sprites.Button('game_again.png', 'game_again_down.png', (240, 390))
    leave_button = sprites.Button('leave_game.png', 'leave_game_down.png', (240, 480))
    gameover_image, _ = load_image('gameover.png', colorkey=-1, scale=(400, 150))

    # Create sprites
    plane = sprites.Plane()
    allsprites = pygame.sprite.RenderPlain((plane))
    # Create 10 missiles and store them in the class variable pool
    sprites.Missile.pool = pygame.sprite.Group([sprites.Missile() for _ in range(10)])
    sprites.Missile.allsprites = allsprites

    # Create enemies
    sprites.EnemyMissile.pool = pygame.sprite.Group([sprites.EnemyMissile() for _ in range(10)])
    sprites.EnemyMissile.allsprites = allsprites
    enemies = pygame.sprite.Group()
    sprites.ExplosionEnemy.allsprites = allsprites
    sprites.ExplosionBoss.allsprites = allsprites
    sprites.Enemy.all_images = [load_image('enemy{}.png'.format(i),
                                           colorkey=-1,
                                           scale=(32, 34))[0] for i in range(1, 6)]

    # Add boss group
    bosses = pygame.sprite.Group()
    sprites.Boss.all_images = [load_image('boss{}.png'.format(i),
                                          colorkey=-1,
                                          scale=(96, 102))[0] for i in range(1, 6)]

    # Create falling objects
    sprites.FallingItem.allsprites = allsprites
    hp_pack = sprites.HpPack()
    powerup = sprites.PowerUp()

    # Create HP bar and let it track plane's hp attr
    hp_bar = sprites.HpBar(plane)

    # Create the clock object
    clock = pygame.time.Clock()

    music.play(loops=-1)  # Looping play background music

    # Enter starting view
    while True:
        clock.tick(60)  # Max FPS = 60
        # Event handling (somehow this needs to be here to make get the mouse position work)
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                pygame.quit()
                return
            if event.type == pygame.KEYDOWN and event.key == pygame.K_ESCAPE:
                pygame.quit()
                return
        screen.blit(background, (0, background1_rect.y))
        screen.blit(background, (0, background2_rect.y))
        start_button.render(screen)
        if start_button.pressed:
            start_button.pressed = False
            break
        pygame.display.update()

    keep_playing = True
    game = 0
    while keep_playing:
        game += 1

        # Re-position the plane
        plane.place_at_bottom_center()

        # Clearing the view by emptying all the groups
        allsprites.empty()
        allsprites.add(plane)
        bosses.empty()
        enemies.empty()
        # Also empty those 'active' groups to avoid invisible missiles collide
        # with our plane or enemies
        sprites.Missile.pool.add(sprites.Missile.active)
        sprites.Missile.active.empty()
        sprites.EnemyMissile.pool.add(sprites.EnemyMissile.active)
        sprites.EnemyMissile.active.empty()

        # Reinitialize the HP and battle constant values of all class and objects
        plane.hp = INITIAL_HP
        sprites.Enemy.initial_hp = sprites.HP_ENEMY
        sprites.Boss.initial_hp = sprites.HP_BOSS
        fire_period = 20
        boss_fire_period = 70

        mark = False # to identify whether enemy adds hp after 1 boss is defeated (enemy level up)
        initial_boss_appear = True # to identify the first appearance of boss
        boss_number_appear = 1 # the number of boss that has appeared including this one

        # Reinitialize loop counter and scores
        score = 0
        frame = 0
        frame_record = 0

        # Enter the main game loop
        while True:
            frame += 1  # Loop counter
            score += 1/30
            clock.tick(60)  # Max FPS = 60

            # Event handling
            for event in pygame.event.get():
                if event.type == pygame.QUIT:
                    pygame.quit()
                    return
                if event.type == pygame.KEYDOWN and event.key == pygame.K_ESCAPE:
                    pygame.quit()
                    return

            # Check if arrow key is pressed, and tell the plane to move
            plane.key_pressed()

            # The plane fires every constant period (frames)
            if not frame % fire_period:
                plane.fire()

            # Randomly put a powerup item on the top of the screen if it is not
            # already on the screen
            if powerup not in allsprites and random.random() <= POWER_UP_PROB:
                powerup.appear()

            # Randomly put a HP pack item on the top of the screen if it is not
            # already on the screen
            if hp_pack not in allsprites and random.random() <= HP_PACK_PROB:
                hp_pack.appear()

            # Enemy's appearnce
            if not frame % 100:
                if len(bosses) == 0:
                    new_enemy = sprites.Enemy()
                    new_enemy.number_appear = boss_number_appear % 5
                    new_enemy.appearnce() # determine the image it appears

                    if mark: # enemy's hp increases since player has entered next level
                        new_enemy.revival()
                        mark = False
                    new_enemy.add(allsprites, enemies)

            # Enemy fires missile
            for a_enemy in enemies:
                a_enemy.fire()

            # Increase missiles fired at once if collided with powerup item
            if powerup in allsprites and pygame.sprite.collide_rect(plane, powerup):
                plane.powerup()
                powerup.kill()

            # Recover HP if collided with HP pack item
            if hp_pack in allsprites and pygame.sprite.collide_rect(plane, hp_pack):
                plane.hp += HP_INCREMENT
                hp_pack.kill()

            # Another boss appears 25 seconds after the previous one is defeated
            if frame == frame_record + 1500:
                new_boss = sprites.Boss()
                new_boss.number_appear = boss_number_appear % 5
                new_boss.appearnce() # determine the image it appears

                if not initial_boss_appear: # Boss has already appeared more than 1 time
                    new_boss.revival() # boss' hp increases
                new_boss.add(allsprites, bosses)

            # Boss fires missile
            if not frame % boss_fire_period:
                for a_boss in bosses:
                    a_boss.fire()

            # Check if enemy collide with our plane
            for a_enemy in enemies:
                if pygame.sprite.collide_circle(plane, a_enemy):
                    plane.hp -= COLLIDE_HP_DROP
                    plane.remove_powerup()
                    a_enemy.kill()

            # Check if enemy's missile hit our plane
            for missile in sprites.EnemyMissile.active:
                if pygame.sprite.collide_circle(plane, missile):
                    missile.recycle()
                    plane.hp -= HIT_HP_DROP
                    plane.remove_powerup()

            # Check if our plane's missile hit enemy
            for a_enemy in enemies:
                for missile in sprites.Missile.active:
                    if pygame.sprite.collide_circle(a_enemy, missile):
                        missile.recycle()
                        a_enemy.hp -= HIT_HP_DROP
                if a_enemy.hp <= 0:
                    score += 40

            # Check if boss collide with our plane
            for a_boss in bosses:
                if pygame.sprite.collide_circle(plane, a_boss):
                    plane.hp -= COLLIDE_HP_DROP
                    plane.remove_powerup()

            # Check if our plane's missile hit boss
            for a_boss in bosses:
                for missile in sprites.Missile.active:
                    if pygame.sprite.collide_circle(a_boss, missile):
                        missile.recycle()
                        a_boss.hp -= HIT_HP_DROP
                if a_boss.hp <= 0:
                    score += 200
                    a_boss.die()
                    mark = True # player entering next level
                    initial_boss_appear = False # launch revival method every time a new boss appears
                    boss_number_appear += 1
                    frame_record = frame # to record the number of frames when a boss is defeated

            # End the game if the HP goes to 0
            if plane.hp <= 0:
                break

            # Update all sprite object's positions
            allsprites.update()

            # Update the score
            score_text = score_font.render('Score : %6d' % score, True, (225, 225, 225))

            # Scroll the background
            background1_rect.y += SCROLLING_SPEED
            if background2_rect.y + background1_rect.y > 640:
                background1_rect.y = 0
            background2_rect.bottom = background1_rect.y

            # Draw Everything
            screen.blit(background, (0, background1_rect.y))
            screen.blit(background, (0, background2_rect.y))
            hp_bar.draw()
            screen.blit(score_text, (10, 5))
            allsprites.draw(screen)
            pygame.display.flip()

        # The end of game view, asking the player to choose if they want to continue
        while True:
            clock.tick(60)  # Max FPS = 60
            # Event handling (somehow this needs to be here to make get the mouse position work)
            for event in pygame.event.get():
                if event.type == pygame.QUIT:
                    pygame.quit()
                    return
                if event.type == pygame.KEYDOWN and event.key == pygame.K_ESCAPE:
                    pygame.quit()
                    return
            screen.blit(background, (0, background1_rect.y))
            screen.blit(background, (0, background2_rect.y))
            screen.blit(gameover_image, (40, 150))
            screen.blit(score_text, (10, 5))
            again_button.render(screen)
            leave_button.render(screen)
            if again_button.pressed:
                again_button.pressed = False
                break
            if leave_button.pressed:
                keep_playing = False
                leave_button.pressed = False
                break
            pygame.display.update()

    pygame.quit()


if __name__ == '__main__':
    main()