波次
Coddy Pygame 项目:守住城堡 课程的第 9 课,共 25 课。
只有史莱姆的一夜会很无聊。现在,起始代码会将夜晚分成 8 波:WAVES 列出每一波会出现的怪物种类,MONSTERS 中的行分别对应蝙蝠(速度快)、蜘蛛和幽灵(速度慢)。
WAVES = [
["slime"],
["slime", "bat"],
...
["bat", "ghost"],
]现在是第几波?在夜晚的前八分之一,self.time * len(WAVES) // NIGHT 的结果是 0;在最后八分之一,结果是 7。加 1 就能从第 1 波开始计数,而 min 会确保在夜晚结束时波数最多为 8:
def wave(self):
return min(len(WAVES), self.time * len(WAVES) // NIGHT + 1)每一波的怪物出现速度也会更快。怪物之间间隔 max(16, 46 - wave * 5) 帧,第 1 波间隔为 41 帧,最后几波为 16 帧,不会更少。random.choice(list) 会从这一波的列表中随机选出一种怪物。
挑战
中等让夜晚的怪物分成 8 波出现,而且一波比一波来得快。
- 在
Night中,按上面的写法编写wave(self)。 - 在
spawn中,先写wave = self.wave();然后每隔max(16, 46 - wave * 5)帧,在edge_point()处添加一个类型为random.choice(WAVES[wave - 1])的怪物。
按“开始”:先出现史莱姆;经过 30 秒后,蝙蝠也会加入,而且速度更快。然后按“检查”。
亲手试试
import random
import pygame
WIDTH, HEIGHT = 720, 480
TILE = 48
NIGHT = 60 * 60 * 4
# 从第一波到最后一波,每波派出的怪物种类
WAVES = [
["slime"],
["slime", "bat"],
["slime", "bat", "spider"],
["bat", "spider"],
["slime", "spider", "ghost"],
["bat", "spider", "ghost"],
["spider", "ghost"],
["bat", "ghost"],
]
WHITE = (240, 240, 240)
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)
big_font = pygame.font.Font("assets/fonts/pixel.ttf", 48)
def load(name):
return pygame.image.load("assets/images/" + name).convert_alpha()
floor_img = load("floor.png")
wall_img = load("wall.png")
knight_img = load("knight.png")
heart_img = load("heart.png")
empty_img = load("heart_empty.png")
MONSTERS = {
"slime": {"image": load("slime.png"), "speed": 1.0},
"bat": {"image": load("dungeon_bat.png"), "speed": 1.6},
"spider": {"image": load("spider.png"), "speed": 1.2},
"ghost": {"image": load("ghost.png"), "speed": 0.8},
}
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))
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
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.pos = pygame.Vector2(pos)
self.rect = pygame.Rect(0, 0, 28, 28)
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
class Night:
def __init__(self):
self.knight = Knight()
self.time = 0
self.monsters = pygame.sprite.Group()
self.state = "playing"
def spawn(self):
if self.time % 60 == 0:
self.monsters.add(Monster("slime", edge_point()))
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
if knight.hearts <= 0:
self.state = "lost"
def update(self, keys):
self.time += 1
self.knight.move(keys)
self.spawn()
self.monsters.update(self.knight.rect.center)
self.take_hits()
night = Night()
running = True
while running:
for event in pygame.event.get():
if event.type == pygame.QUIT:
running = False
if night.state == "playing":
night.update(pygame.key.get_pressed())
screen.blit(background, (0, 0))
knight = night.knight
for monster in night.monsters:
draw(monster.image, monster.rect.center)
if knight.hurt % 10 < 5:
draw(knight.image, knight.rect.center)
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)))
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()
这节课包含一个小测验。开始学习即可作答,并记录你的进度。
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