اتبع المستكشف

جزء من قسم العوالم في رحلة Pygame على Coddy. الدرس 30 من 35.

يمتد الكهف على عرض أربع نوافذ، لذا تتبع الكاميرا المستكشف، كما في الكاميرا ذات التمرير. بعد تحريك اللاعب، اجعل الكاميرا تتمركز عليه وأبقِه داخل المستوى:

camera_x = player.centerx - WIDTH // 2
camera_x = max(0, min(camera_x, level_width - WIDTH))

ارسم كل بلاطة واللاعب عند إحداثي x الخاص به مطروحًا منه camera_x. تقع خلفية الغابة بعيدًا، لذا تتحرك بسرعة تساوي ثلث السرعة، وتتكرر كل 72 بكسلًا:

shift = camera_x // 3 % 72
for y in range(0, HEIGHT, 72):
    for x in range(-shift, WIDTH, 72):
        screen.blit(background, (x, y))

اجعل level_width = len(LEVEL[0]) * TILE وcamera_x = 0 قبل الحلقة.

التحدي

سهل

قبل الحلقة، احسب level_width من الخريطة واجعل camera_x = 0.
في نهاية تحديث كل إطار، اضبط camera_x ليتبع اللاعب، واحصره بين 0 وlevel_width - WIDTH.
ارسم الخلفية باستخدام shift = camera_x // 3 % 72، وابدأ كل صف عند -shift.
ارسم البلاطات عند (rect.x - camera_x, rect.y) واللاعب عند (player.x - camera_x, player.y).

جرّب بنفسك

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()