钥匙和门

本课属于 Coddy Pygame 学习旅程的“项目”单元。第 25 课，共 33 课。

右侧墙上的门锁着。骑士走过钥匙时会捡起它，拿到钥匙后，碰到门就能把门打开。

锁着的门又多了一样会挡住骑士的东西。Room 上的一个方法会返回阻挡骑士的 Rect 列表：

def blocks(self):
    if self.door_open:
        return self.walls
    return self.walls + [self.door]

碰到门有个问题：move 每一帧都会把骑士推出门外，所以他的 Rect 永远不会与门重叠。knight.rect.inflate(8, 8) 是他的 Rect 的副本，每一侧都扩大了 4 像素，这个副本确实会与他紧贴着的门重叠。

if room.has_key and knight.rect.inflate(8, 8).colliderect(room.door):
    room.door_open = True

打开的门外就是窗口边缘，所以用 clamp_ip 把骑士限制在窗口内。在后续的课中，门口会通往下一个房间。骑士拿着钥匙时，把钥匙显示在屏幕顶部。

挑战

中等

在骑士找到钥匙之前，锁住门。

在 Room 中：self.has_key = False 和 self.door_open = False；K 设置 self.key = cell_rect(col, row)，D 将 self.door 设置为一个 48 × 48 的瓷砖 Rect。
添加 blocks()；调用 knight.move(dx, dy, room.blocks())，然后调用 knight.rect.clamp_ip(screen.get_rect())。
碰到 room.key 时，将其设置为 room.has_key = True；然后按上述方式打开门。

点击“开始”：拿到钥匙之前，门会保持关闭。然后点击“检查”。

亲手试试

import pygame

TILE = 48
MAP = [
    "##############",
    "#............#",
    "#.P......K...#",
    "#............#",
    "#....##......D",
    "#....##......#",
    "##.#######.###",
    "#............#",
    "#...S....H...#",
    "##############",
]

pygame.init()
screen = pygame.display.set_mode((672, 480))
pygame.display.set_caption("Rune Keep")
clock = pygame.time.Clock()
font = pygame.font.Font("assets/fonts/pixel.ttf", 32)


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")
door_img = load("dungeon_door.png")
key_img = load("key.png")
slime_img = load("slime.png")
spider_img = load("spider.png")
heart_img = load("heart.png")
empty_img = load("heart_empty.png")
sword_img = load("sword.png")
potion_img = load("potion_red.png")


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


def cell_rect(col, row):
    rect = pygame.Rect(0, 0, 32, 32)
    rect.center = (col * TILE + 24, row * TILE + 24)
    return rect


class Room:
    def __init__(self, lines):
        self.walls = []
        self.start = (72, 72)
        for row, line in enumerate(lines):
            for col, char in enumerate(line):
                if char == "#":
                    self.walls.append(pygame.Rect(col * TILE, row * TILE, TILE, TILE))
                elif char == "P":
                    self.start = cell_rect(col, row).center


class Knight(pygame.sprite.Sprite):
    def __init__(self, center):
        super().__init__()
        self.image = knight_img
        self.rect = pygame.Rect(0, 0, 32, 32)
        self.rect.center = center

    def move(self, dx, dy, blocks):
        self.rect.x += dx
        for block in blocks:
            if self.rect.colliderect(block):
                if dx > 0:
                    self.rect.right = block.left
                elif dx < 0:
                    self.rect.left = block.right
        self.rect.y += dy
        for block in blocks:
            if self.rect.colliderect(block):
                if dy > 0:
                    self.rect.bottom = block.top
                elif dy < 0:
                    self.rect.top = block.bottom


room = Room(MAP)
knight = Knight(room.start)

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

    keys = pygame.key.get_pressed()
    dx = 0
    dy = 0
    if keys[pygame.K_LEFT]:
        dx = -3
    if keys[pygame.K_RIGHT]:
        dx = 3
    if keys[pygame.K_UP]:
        dy = -3
    if keys[pygame.K_DOWN]:
        dy = 3
    knight.move(dx, dy, room.walls)

    for row in range(10):
        for col in range(14):
            screen.blit(floor_img, (col * TILE, row * TILE))
    for wall in room.walls:
        screen.blit(wall_img, wall)
    draw(knight.image, knight.rect)
    pygame.display.flip()
    clock.tick(60)

pygame.quit()

项目中的所有课

自己练习： Pygame 在线编辑器