跟随探险者
本课属于 Coddy Pygame 学习旅程的“游戏世界”单元。第 30 课，共 36 课。
洞穴的宽度为 4 个窗口，因此镜头会跟随探险者，就像在《滚动镜头》中一样。玩家移动后，将镜头对准玩家，并让镜头保持在关卡范围内：
camera_x = player.centerx - WIDTH // 2
camera_x = max(0, min(camera_x, level_width - WIDTH))绘制每块瓦片和玩家时，都将它们的 x 坐标减去 camera_x。森林背景离得很远，所以它移动的速度只有三分之一，并且每隔 72 像素重复一次：
shift = camera_x // 3 % 72
for y in range(0, HEIGHT, 72):
for x in range(-shift, WIDTH, 72):
screen.blit(background, (x, y))在循环开始前，设置 level_width = len(LEVEL[0]) * TILE 和 camera_x = 0。
挑战
简单让摄像机跟随探索者穿过洞穴。
- 在循环之前，根据地图创建
level_width，并设置camera_x = 0。 - 更新后，让
camera_x跟随玩家，并限制在0和level_width - WIDTH之间。 - 使用
shift = camera_x // 3 % 72，从 x 坐标-shift开始绘制背景；绘制图块和玩家时，x 坐标减去camera_x。
按“开始”，然后向右走：洞穴会随着你移动。接着按“检查”。
亲手试试
import pygame
TILE = 36
WIDTH, HEIGHT = 576, 360
SPEED = 4
GRAVITY = 1
JUMP = -15
MAX_FALL = 12
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)
vel_y = 0
on_ground = False
running = True
while running:
for event in pygame.event.get():
if event.type == pygame.QUIT:
running = False
elif event.type == pygame.KEYDOWN and event.key in (pygame.K_SPACE, pygame.K_UP):
if on_ground:
vel_y = JUMP
elif event.type == pygame.KEYUP and event.key in (pygame.K_SPACE, pygame.K_UP):
if vel_y < -4:
vel_y = -4
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
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
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