奔跑与跳跃

本课属于 Coddy Pygame 学习旅程的“游戏世界”单元。第 29 课，共 36 课。

现在，探索者可以移动了，并实现了重力、跳跃和平台碰撞。每一帧，先沿 x 轴移动并推出墙壁，然后施加重力，沿 y 轴移动并着陆或撞到头部，接着检测是否掉出洞穴：

keys = pygame.key.get_pressed()
dx = 0
if keys[pygame.K_LEFT]:
    dx -= SPEED
if keys[pygame.K_RIGHT]:
    dx += SPEED

player.x += dx
for wall in walls:
    if player.colliderect(wall):
        if dx > 0:
            player.right = wall.left
        elif dx < 0:
            player.left = wall.right

vel_y = min(vel_y + GRAVITY, MAX_FALL)
player.y += vel_y
on_ground = False
for wall in walls:
    if player.colliderect(wall):
        if vel_y > 0:
            player.bottom = wall.top
            on_ground = True
        elif vel_y < 0:
            player.top = wall.bottom
        vel_y = 0

if player.top > HEIGHT:
    player.midbottom = start
    vel_y = 0

跳跃逻辑放在事件循环中：当角色处于 on_ground 状态时，按下空格键或向上键会触发 KEYDOWN 事件，并设置 vel_y = JUMP；按键松开时触发 KEYUP 事件，会将快速上升的速度截断为 -4，让角色跳得较低。

在顶部添加速度常量：SPEED = 4、GRAVITY = 1、JUMP = -15、MAX_FALL = 12。使用这些数值，角色跳起约 100 像素：足以跳上两格高的平台，也足以越过两格宽的坑。

挑战

中等

让探险者跑、跳和下落。

在顶部添加 SPEED = 4、GRAVITY = 1、JUMP = -15 和 MAX_FALL = 12，并在循环之前添加 vel_y = 0 和 on_ground = False。
在事件处理中添加跳跃和短跳。
在事件处理之后，添加所示的每帧代码。

按“开始”，然后走进第一个坑里：你会重新开始。接着按“检查”。

亲手试试

import pygame

TILE = 36
WIDTH, HEIGHT = 576, 360

LEVEL = [
    "................................................................",
    "................................................................",
    "................................................................",
    "................................................................",
    "#..............................................................#",
    "#....................C.........................#####...........#",
    "#......CC...C................CC.....CC.........#####.....CC....#",
    "#....................#.........................D...............#",
    "#.P.........#...E....#...^.......K......E......D.C....^......F.#",
    "#######..####################..##########################..#####",
]

pygame.init()
screen = pygame.display.set_mode((WIDTH, HEIGHT))
pygame.display.set_caption("Moss Caves")
clock = pygame.time.Clock()


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


background = pygame.image.load("assets/backgrounds/forest.png").convert_alpha()
grass_img = load("grass.png")
grass_left_img = load("grass_left.png")
grass_right_img = load("grass_right.png")
dirt_img = load("dirt.png")
player_img = load("player.png")


def solid(row, col):
    if row < 0 or row >= len(LEVEL) or col < 0 or col >= len(LEVEL[0]):
        return False
    return LEVEL[row][col] == "#"


walls = []
tiles = []
for row, line in enumerate(LEVEL):
    for col, char in enumerate(line):
        rect = pygame.Rect(col * TILE, row * TILE, TILE, TILE)
        if char == "#":
            if solid(row - 1, col):
                image = dirt_img
            elif not solid(row, col - 1) and solid(row, col + 1):
                image = grass_left_img
            elif solid(row, col - 1) and not solid(row, col + 1):
                image = grass_right_img
            else:
                image = grass_img
            walls.append(rect)
            tiles.append((image, rect))
        elif char == "P":
            start = rect.midbottom

player = player_img.get_rect(midbottom=start)

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

    for y in range(0, HEIGHT, 72):
        for x in range(0, WIDTH, 72):
            screen.blit(background, (x, y))
    for image, rect in tiles:
        screen.blit(image, rect)
    screen.blit(player_img, player)
    pygame.display.flip()
    clock.tick(60)

pygame.quit()

游戏世界中的所有课

自己练习： Pygame 在线编辑器