Der Boss ruft Fledermäuse

Lektion 17 von 20 im Kurs Pygame-Projekt: Verteidige den Bergfried von Coddy.

Ein guter Boss verändert sich im Laufe des Kampfes. Bei weniger als der Hälfte seiner Lebenspunkte ruft dieser hier um Hilfe: Alle zwei Sekunden erscheinen drei Fledermäuse um ihn herum. Kämpfe mit solchen Abschnitten nennt man Phasen.

boss = self.boss
if boss and boss.alive() and boss.hp < MONSTERS["boss"]["hp"] // 2:
    if self.time % 120 == 0:
        for _ in range(3):
            offset = (random.randint(-50, 50), random.randint(-50, 50))
            self.monsters.add(Monster("bat", boss.pos + offset))

boss and boss.alive() bedeutet: Es gibt einen Boss, und er ist nicht besiegt. and bricht beim ersten falschen Teil ab, daher wird boss.alive() niemals für None aufgerufen.

Ein Vector2 plus ein Tupel aus zwei Zahlen ergibt einen Vector2, also ist boss.pos + offset ein Punkt in der Nähe des Bosses.

Aufgabe

Mittel

Füge am Ende von spawn, solange der Boss noch lebt und weniger als die Hälfte seiner 120 Lebenspunkte hat, alle 120 Frames drei Fledermäuse hinzu, die jeweils in x- und y-Richtung bis zu 50 Pixel vom Boss entfernt sind.

Probier es selbst

import random
import pygame

WIDTH, HEIGHT = 720, 480
TILE = 48
NIGHT = 60 * 60 * 4
BOSS_AT = NIGHT - 60 * 60
WAVES = [
    ["slime"],
    ["slime", "bat"],
    ["slime", "bat", "spider"],
    ["bat", "spider"],
    ["slime", "spider", "ghost"],
    ["bat", "spider", "ghost"],
    ["spider", "ghost"],
    ["bat", "ghost"],
]
UPGRADES = {
    "Quick bolts": "Bolts fire more often",
    "Sharp bolts": "Bolts hit harder",
    "Spinning axe": "One more axe circles you",
    "Swift boots": "You walk faster",
    "Gem magnet": "Gems come from further",
    "Hearty meal": "Get back a heart",
}
WHITE = (240, 240, 240)
BOLT = (120, 200, 255)
GOLD = (250, 200, 60)

pygame.init()
screen = pygame.display.set_mode((WIDTH, HEIGHT))
pygame.display.set_caption("Hold the Keep")
clock = pygame.time.Clock()
font = pygame.font.Font("assets/fonts/pixel.ttf", 24)
small_font = pygame.font.Font("assets/fonts/pixel.ttf", 16)
big_font = pygame.font.Font("assets/fonts/pixel.ttf", 48)


def load(name):
    return pygame.image.load("assets/images/" + name).convert_alpha()


def sound(name):
    return pygame.mixer.Sound("assets/sounds/" + name)


def whiten(image):
    white = image.copy()
    white.fill((255, 255, 255), special_flags=pygame.BLEND_RGB_MAX)
    return white


floor_img = load("floor.png")
wall_img = load("wall.png")
knight_img = load("knight.png")
axe_img = load("axe.png")
gem_img = load("gem.png")
heart_img = load("heart.png")
empty_img = load("heart_empty.png")
MONSTERS = {
    "slime": {"image": load("slime.png"), "speed": 1.0, "hp": 1, "size": 28},
    "bat": {"image": load("dungeon_bat.png"), "speed": 1.6, "hp": 1, "size": 28},
    "spider": {"image": load("spider.png"), "speed": 1.2, "hp": 3, "size": 28},
    "ghost": {"image": load("ghost.png"), "speed": 0.8, "hp": 4, "size": 28},
    "boss": {"image": pygame.transform.scale(load("ghost.png"), (96, 96)), "speed": 0.7, "hp": 120, "size": 64},
}
hit_sound = sound("hit.ogg")
hurt_sound = sound("thud.ogg")
gem_sound = sound("coin.ogg")
level_sound = sound("powerup.ogg")

courtyard = pygame.Rect(TILE, TILE, WIDTH - 2 * TILE, HEIGHT - 2 * TILE)
background = pygame.Surface((WIDTH, HEIGHT))
for row in range(HEIGHT // TILE):
    for col in range(WIDTH // TILE):
        x = col * TILE
        y = row * TILE
        if courtyard.collidepoint(x, y):
            background.blit(floor_img, (x, y))
        else:
            background.blit(wall_img, (x, y))
cover = pygame.Surface((WIDTH, HEIGHT), pygame.SRCALPHA)
cover.fill((0, 0, 0, 150))


def draw(image, center):
    screen.blit(image, image.get_rect(center=center))


def clock_text(frames):
    seconds = frames // 60
    return f"{seconds // 60}:{seconds % 60:02d}"


def edge_point():
    side = random.randint(0, 3)
    if side == 0:
        return (random.randint(0, WIDTH), -24)
    if side == 1:
        return (random.randint(0, WIDTH), HEIGHT + 24)
    if side == 2:
        return (-24, random.randint(0, HEIGHT))
    return (WIDTH + 24, random.randint(0, HEIGHT))


class Knight(pygame.sprite.Sprite):
    def __init__(self):
        super().__init__()
        self.image = knight_img
        self.rect = pygame.Rect(0, 0, 24, 24)
        self.rect.center = courtyard.center
        self.speed = 3
        self.hearts = 5
        self.max_hearts = 5
        self.hurt = 0
        self.bolt_wait = 30
        self.bolt_damage = 1
        self.axes = 1
        self.magnet = 80

    def move(self, keys):
        if keys[pygame.K_LEFT]:
            self.rect.x -= self.speed
        if keys[pygame.K_RIGHT]:
            self.rect.x += self.speed
        if keys[pygame.K_UP]:
            self.rect.y -= self.speed
        if keys[pygame.K_DOWN]:
            self.rect.y += self.speed
        self.rect.clamp_ip(courtyard)


class Monster(pygame.sprite.Sprite):
    def __init__(self, kind, pos):
        super().__init__()
        self.kind = kind
        self.image = MONSTERS[kind]["image"]
        self.speed = MONSTERS[kind]["speed"]
        self.hp = MONSTERS[kind]["hp"]
        self.axe_wait = 0
        self.flash = 0
        self.pos = pygame.Vector2(pos)
        self.rect = pygame.Rect(0, 0, MONSTERS[kind]["size"], MONSTERS[kind]["size"])
        self.rect.center = self.pos

    def update(self, target):
        step = pygame.Vector2(target) - self.pos
        if step.length() > 0:
            self.pos += step.normalize() * self.speed
        self.rect.center = self.pos
        if self.axe_wait > 0:
            self.axe_wait -= 1
        if self.flash > 0:
            self.flash -= 1

    def hit(self, damage):
        self.hp -= damage
        self.flash = 6
        hit_sound.play()


class Bolt(pygame.sprite.Sprite):
    def __init__(self, start, target, damage):
        super().__init__()
        self.pos = pygame.Vector2(start)
        step = pygame.Vector2(target) - self.pos
        if step.length() == 0:
            step = pygame.Vector2(1, 0)
        self.velocity = step.normalize() * 7
        self.damage = damage
        self.rect = pygame.Rect(0, 0, 10, 10)
        self.rect.center = self.pos

    def update(self):
        self.pos += self.velocity
        self.rect.center = self.pos
        if not screen.get_rect().colliderect(self.rect):
            self.kill()


class Gem(pygame.sprite.Sprite):
    def __init__(self, pos):
        super().__init__()
        self.rect = pygame.Rect(0, 0, 24, 24)
        self.rect.center = pos
        self.rect.clamp_ip(courtyard)
        self.pos = pygame.Vector2(self.rect.center)

    def update(self, knight):
        target = pygame.Vector2(knight.rect.center)
        if self.pos.distance_to(target) < knight.magnet:
            self.pos.move_towards_ip(target, 6)
        self.rect.center = self.pos


class Night:
    def __init__(self):
        self.knight = Knight()
        self.time = 0
        self.monsters = pygame.sprite.Group()
        self.bolts = pygame.sprite.Group()
        self.bolt_timer = 0
        self.spin = 0
        self.gems = pygame.sprite.Group()
        self.xp = 0
        self.level = 1
        self.need = 5
        self.choices = []
        self.pick = 0
        self.boss = None
        self.state = "playing"

    def wave(self):
        return min(len(WAVES), self.time * len(WAVES) // NIGHT + 1)

    def spawn(self):
        wave = self.wave()
        if self.time % max(16, 46 - wave * 5) == 0:
            kind = random.choice(WAVES[wave - 1])
            self.monsters.add(Monster(kind, edge_point()))
        if self.boss is None and self.time >= BOSS_AT:
            self.boss = Monster("boss", (WIDTH // 2, -40))
            self.monsters.add(self.boss)

    def nearest(self):
        point = pygame.Vector2(self.knight.rect.center)
        best = None
        for monster in self.monsters:
            if best is None or point.distance_to(monster.pos) < point.distance_to(best.pos):
                best = monster
        return best

    def shoot(self):
        self.bolt_timer += 1
        target = self.nearest()
        if self.bolt_timer >= self.knight.bolt_wait and target is not None:
            self.bolt_timer = 0
            bolt = Bolt(self.knight.rect.center, target.pos, self.knight.bolt_damage)
            self.bolts.add(bolt)

    def axe_spots(self):
        spots = []
        for i in range(self.knight.axes):
            angle = self.spin + i * 360 / self.knight.axes
            offset = pygame.Vector2(70, 0).rotate(angle)
            spots.append(pygame.Vector2(self.knight.rect.center) + offset)
        return spots

    def hurt_monsters(self):
        for bolt in self.bolts:
            target = pygame.sprite.spritecollideany(bolt, self.monsters)
            if target is not None:
                target.hit(bolt.damage)
                bolt.kill()
        for spot in self.axe_spots():
            blade = pygame.Rect(0, 0, 36, 36)
            blade.center = spot
            for monster in self.monsters:
                if monster.axe_wait == 0 and blade.colliderect(monster.rect):
                    monster.hit(1)
                    monster.axe_wait = 20
        for monster in list(self.monsters):
            if monster.hp <= 0:
                monster.kill()
                drops = 8 if monster.kind == "boss" else 1
                for _ in range(drops):
                    self.gems.add(Gem(monster.pos))

    def collect(self):
        for gem in pygame.sprite.spritecollide(self.knight, self.gems, True):
            self.xp += 1
            gem_sound.play()
        if self.xp >= self.need:
            self.xp -= self.need
            self.level += 1
            self.need += 4
            self.choices = random.sample(list(UPGRADES), 3)
            self.pick = 1
            self.state = "levelup"
            level_sound.play()

    def upgrade(self, name):
        knight = self.knight
        if name == "Quick bolts":
            knight.bolt_wait = max(8, knight.bolt_wait - 8)
        elif name == "Sharp bolts":
            knight.bolt_damage += 1
        elif name == "Spinning axe":
            knight.axes += 1
        elif name == "Swift boots":
            knight.speed += 1
        elif name == "Gem magnet":
            knight.magnet += 40
        elif name == "Hearty meal":
            knight.hearts = min(knight.max_hearts, knight.hearts + 1)
        self.state = "playing"

    def take_hits(self):
        knight = self.knight
        if knight.hurt > 0:
            knight.hurt -= 1
        elif pygame.sprite.spritecollideany(knight, self.monsters):
            knight.hearts -= 1
            knight.hurt = 75
            hurt_sound.play()
            if knight.hearts <= 0:
                self.state = "lost"

    def update(self, keys):
        self.time += 1
        self.spin = (self.spin + 4) % 360
        self.knight.move(keys)
        self.spawn()
        self.monsters.update(self.knight.rect.center)
        self.bolts.update()
        self.gems.update(self.knight)
        self.shoot()
        self.hurt_monsters()
        self.collect()
        self.take_hits()


night = Night()

running = True
while running:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False
        elif event.type == pygame.KEYDOWN:
            if night.state == "levelup":
                if event.key == pygame.K_LEFT:
                    night.pick = (night.pick - 1) % 3
                elif event.key == pygame.K_RIGHT:
                    night.pick = (night.pick + 1) % 3
                elif event.key == pygame.K_SPACE:
                    night.upgrade(night.choices[night.pick])

    if night.state == "playing":
        night.update(pygame.key.get_pressed())

    screen.blit(background, (0, 0))
    knight = night.knight
    for gem in night.gems:
        draw(gem_img, gem.rect.center)
    for monster in night.monsters:
        if monster.flash > 0:
            draw(whiten(monster.image), monster.rect.center)
        else:
            draw(monster.image, monster.rect.center)
    if knight.hurt % 10 < 5:
        draw(knight.image, knight.rect.center)
    for spot in night.axe_spots():
        draw(pygame.transform.rotate(axe_img, -night.spin * 3), spot)
    for bolt in night.bolts:
        pygame.draw.circle(screen, BOLT, bolt.rect.center, 5)
    for i in range(knight.max_hearts):
        if i < knight.hearts:
            screen.blit(heart_img, (8 + i * 34, 6))
        else:
            screen.blit(empty_img, (8 + i * 34, 6))
    left = font.render(clock_text(max(0, NIGHT - night.time)) + " until dawn", True, WHITE)
    screen.blit(left, left.get_rect(center=(WIDTH // 2, 24)))
    label = font.render(f"Level {night.level}", True, WHITE)
    screen.blit(label, label.get_rect(topright=(WIDTH - 10, 4)))
    pygame.draw.rect(screen, (40, 40, 60), (WIDTH - 160, 30, 150, 10))
    pygame.draw.rect(screen, GOLD, (WIDTH - 160, 30, 150 * night.xp // night.need, 10))
    if night.state == "levelup":
        screen.blit(cover, (0, 0))
        title = big_font.render("Level up! Pick one", True, GOLD)
        screen.blit(title, title.get_rect(center=(WIDTH // 2, 130)))
        for i, name in enumerate(night.choices):
            card = pygame.Rect(60 + i * 210, 190, 180, 120)
            pygame.draw.rect(screen, (40, 40, 60), card)
            if i == night.pick:
                pygame.draw.rect(screen, GOLD, card, 4)
            else:
                pygame.draw.rect(screen, WHITE, card, 2)
            text = font.render(name, True, WHITE)
            screen.blit(text, text.get_rect(center=(card.centerx, card.y + 40)))
            about = small_font.render(UPGRADES[name], True, WHITE)
            screen.blit(about, about.get_rect(center=(card.centerx, card.y + 80)))
        hint = font.render("Left and Right to choose, Space to take it", True, WHITE)
        screen.blit(hint, hint.get_rect(center=(WIDTH // 2, 360)))
    if night.state == "lost":
        message = big_font.render("The keep has fallen", True, WHITE)
        screen.blit(message, message.get_rect(center=(WIDTH // 2, 200)))
    pygame.display.flip()
    clock.tick(60)

pygame.quit()