👾 Make a Space Game · สร้างเกมอวกาศ · 做一个太空游戏

0 Get ready · เตรียมตัว · 做好准备

pip3 install pygame

mkdir ~/Documents/Code/space
cd ~/Documents/Code/space
vim space_invaders.py

1 The entry point · จุดเริ่มต้นของโปรแกรม · 程序的入口

def main():
    print("The game starts here!")


if __name__ == "__main__":
    main()

2 Open a window · เปิดหน้าต่างเกม · 打开一个窗口

import pygame

WIDTH = 960
HEIGHT = 640


def main():
    pygame.init()
    screen = pygame.display.set_mode((WIDTH, HEIGHT))
    pygame.display.set_caption("Space Invaders")

    running = True
    while running:
        # 1. look at events
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                running = False

        # 2. draw
        screen.fill((10, 12, 30))

        # 3. show it
        pygame.display.flip()

    pygame.quit()


if __name__ == "__main__":
    main()

3 Slow it down with a clock · ใส่นาฬิกาเพื่อคุมความเร็ว · 用时钟控制速度

FPS = 60

    clock = pygame.time.Clock()

        clock.tick(FPS)

4 Our first class: the player · คลาสแรกของเรา: ผู้เล่น · 第一个类：玩家

WHITE = (255, 255, 255)


class Player:
    def __init__(self):
        self.x = WIDTH // 2
        self.y = HEIGHT - 70
        self.speed = 6
        self.lives = 3
        self.score = 0

    def draw(self, screen):
        pygame.draw.rect(screen, WHITE, (self.x - 20, self.y - 10, 40, 20))

    player = Player()

        player.draw(screen)

5 Make the player move · ทำให้ผู้เล่นเคลื่อนที่ · 让玩家动起来

    def update(self, keys):
        if keys[pygame.K_LEFT]:
            self.x -= self.speed
        if keys[pygame.K_RIGHT]:
            self.x += self.speed

        if self.x < 20:
            self.x = 20
        if self.x > WIDTH - 20:
            self.x = WIDTH - 20

        keys = pygame.key.get_pressed()
        player.update(keys)

6 A class for bullets · คลาสสำหรับกระสุน · 子弹的类

YELLOW = (255, 220, 60)


class Bullet:
    def __init__(self, x, y, speed, colour):
        self.x = x
        self.y = y
        self.speed = speed          # up is negative, down is positive
        self.colour = colour

    def update(self):
        self.y += self.speed

    def is_gone(self):
        return self.y < -20 or self.y > HEIGHT + 20

    def rect(self):
        return pygame.Rect(self.x - 2, self.y - 8, 4, 16)

    def draw(self, screen):
        pygame.draw.rect(screen, self.colour, self.rect())

    my_bullets = []

        for event in pygame.event.get():
            if event.type == pygame.QUIT:          # you already have this
                running = False
            elif event.type == pygame.KEYDOWN and event.key == pygame.K_SPACE:
                my_bullets.append(Bullet(player.x, player.y - 24, -10, YELLOW))

        for bullet in my_bullets:
            bullet.update()
            bullet.draw(screen)
        my_bullets = [b for b in my_bullets if not b.is_gone()]

7 The creep class — the important one · คลาสของศัตรู — คลาสสำคัญ · 敌人的类 —— 最重要的一个

import math
import random

RED = (255, 80, 80)


class Creep:
    def __init__(self, image, y, speed, path, hp, fire_rate):
        self.image = image
        self.x = -50                # every creep starts off the left edge
        self.start_y = y
        self.y = y
        self.speed = speed
        self.path = path            # "straight" or "curve"
        self.hp = hp                # 1, 2 or 3
        self.fire_rate = fire_rate  # small number = shoots often
        self.timer = random.randint(0, fire_rate)
        self.wave = 0.0

    def update(self):
        self.x += self.speed

        if self.path == "curve":
            self.wave += 0.04
            self.y = self.start_y + math.sin(self.wave) * 70

        self.timer += 1

    def wants_to_shoot(self):
        if self.timer >= self.fire_rate:
            self.timer = 0
            return True
        return False

    def is_gone(self):
        return self.x > WIDTH + 60

8 Many creeps, all different · ศัตรูหลายตัว ต่างกันหมด · 很多敌人，各不相同

def make_creep(images):
    hp = random.choice([1, 1, 2, 2, 3])

    return Creep(
        image=images[hp],
        y=random.randint(70, HEIGHT // 2),
        speed=random.uniform(1.0, 3.2),
        path=random.choice(["straight", "curve"]),
        hp=hp,
        fire_rate=random.randint(70, 200),
    )

    creeps = []
    spawn_timer = 0

        spawn_timer += 1
        if spawn_timer >= 45:
            spawn_timer = 0
            creeps.append(make_creep(creep_images))

        for creep in creeps:
            creep.update()
            creep.draw(screen)
        creeps = [c for c in creeps if not c.is_gone()]

9 The creeps shoot back · ศัตรูยิงตอบ · 敌人开始还击

    their_bullets = []

        for creep in creeps:
            creep.update()
            if creep.wants_to_shoot():
                their_bullets.append(Bullet(creep.x, creep.y + 20, 5, RED))

10 Hits and hit points · การโดนยิงและพลังชีวิต · 命中与血量

        for bullet in list(my_bullets):
            for creep in list(creeps):
                if bullet.rect().colliderect(creep.rect()):
                    my_bullets.remove(bullet)
                    creep.hp -= 1                  # take one hit point away
                    if creep.hp <= 0:
                        creeps.remove(creep)
                        player.score += 10
                    break

        for bullet in list(their_bullets):
            if bullet.rect().colliderect(player.rect()):
                their_bullets.remove(bullet)
                player.lives -= 1

11 Score, lives and game over · คะแนน ชีวิต และจบเกม · 分数、生命和游戏结束

    font = pygame.font.SysFont(None, 30)
    playing = True

        screen.blit(font.render(f"Score {player.score}", True, WHITE), (16, 14))
        screen.blit(font.render(f"Lives {player.lives}", True, WHITE), (WIDTH - 110, 14))

        for bullet in list(their_bullets):         # you already have this
            if bullet.rect().colliderect(player.rect()):
                their_bullets.remove(bullet)
                player.lives -= 1
                if player.lives <= 0:              # add these two lines
                    playing = False

        for event in pygame.event.get():
            if event.type == pygame.QUIT:          # you already have this
                running = False
            elif event.type == pygame.KEYDOWN and event.key == pygame.K_r and not playing:
                player = Player()                  # a brand new object
                creeps = []
                playing = True

12 Add the pictures · ใส่รูปภาพ · 加上图片

from pathlib import Path

PICTURES = ["background.png", "player.png", "creep1.png", "creep2.png", "creep3.png"]


def find_image_dir():
    here = Path(__file__).resolve().parent
    for folder in (here / "images", here):
        if (folder / "background.png").exists():
            return folder
    return here / "images"          # nothing found - report this one


IMAGE_DIR = find_image_dir()


def report_images():
    found = [n for n in PICTURES if (IMAGE_DIR / n).exists()]
    print(f"Looking for pictures in: {IMAGE_DIR}")
    print(f"Found {len(found)} of {len(PICTURES)}.")
    if len(found) < len(PICTURES):
        print("The game still works. It draws coloured boxes instead.")


def load_image(name, size, colour):
    path = IMAGE_DIR / name
    if path.exists():
        picture = pygame.image.load(str(path)).convert_alpha()
        return pygame.transform.smoothscale(picture, size)
    box = pygame.Surface(size, pygame.SRCALPHA)
    box.fill(colour)
    return box

    report_images()

    background = load_image("background.png", (WIDTH, HEIGHT), DARK)
    player_image = load_image("player.png", (54, 54), WHITE)
    creep_images = {
        1: load_image("creep1.png", (48, 48), (90, 220, 230)),
        2: load_image("creep2.png", (56, 56), (240, 160, 60)),
        3: load_image("creep3.png", (64, 64), (190, 110, 230)),
    }

13 The whole game · เกมทั้งหมด · 完整的游戏

cd ~/Documents/Code/space
mkdir images          # put the five pictures in here
python3 space_invaders.py

14 Now change it · ลองแก้ดู · 现在动手改它