python - 如何轻松更改代码的功能？

Question

我想让我的游戏“返回”到主菜单，我想知道我是否可以在它自己的“内部”使用游戏窗口功能，以便它创建一个“重置”。基本上，如果我的 Sprite 碰撞并显示“游戏结束”，我想按“后退”按钮，如果我再次按播放，它会显示一个“重置”的游戏，其中“计时器”、“小行星” ”，“船”，仿佛又在玩一个新游戏一样回到了起点。

我还想知道给我的任何错误是否对我的问题有任何意义？

代码/游戏大部分都在工作。它只是没有“重置”的目的。

这是错误:

"C:\Users\Myke Sustento\AppData\Local\Programs\Python\Python38-32\python.exe" "B:/PROGRAMMING RELATED/PYTHON PROJECTS/FINAL.py"
B:/PROGRAMMING RELATED/PYTHON PROJECTS/FINAL.py:261: SyntaxWarning: "is" with a literal. Did you mean "=="?
  if bullet_state is "fire":
B:/PROGRAMMING RELATED/PYTHON PROJECTS/FINAL.py:322: SyntaxWarning: "is" with a literal. Did you mean "=="?
  if bullet_state is "ready":
pygame 1.9.6
Hello from the pygame community. https://www.pygame.org/contribute.html
B:/PROGRAMMING RELATED/PYTHON PROJECTS/FINAL.py:171: DeprecationWarning: an integer is required (got type float).  Implicit conversion to integers using __int__ is deprecated, and may be removed in a future version of Python.
  display.blit(ammoboximg,(x,y))
Traceback (most recent call last):
  File "B:/PROGRAMMING RELATED/PYTHON PROJECTS/FINAL.py", line 374, in <module>
    gamewindow()
  File "B:/PROGRAMMING RELATED/PYTHON PROJECTS/FINAL.py", line 315, in gamewindow
    gamewindow()
  File "B:/PROGRAMMING RELATED/PYTHON PROJECTS/FINAL.py", line 315, in gamewindow
    gamewindow()
  File "B:/PROGRAMMING RELATED/PYTHON PROJECTS/FINAL.py", line 315, in gamewindow
    gamewindow()
  File "B:/PROGRAMMING RELATED/PYTHON PROJECTS/FINAL.py", line 330, in gamewindow
    keys = pygame.key.get_pressed()
pygame.error: video system not initialized

Process finished with exit code 1

这是整个代码:

# initialization of pygame
import pygame
import random
import math


pygame.init()
# creating the display
display = pygame.display.set_mode((500, 500))

# title & icon
spaceship = pygame.image.load("Space Blitz Sprites/spaceship.png")
pygame.display.set_icon(spaceship)
pygame.display.set_caption("SpaceBlitz")

# main menu sprites
spaceblitz = pygame.image.load("Space Blitz Sprites/spaceblitz.png")
play = pygame.image.load("Space Blitz Sprites/play.png")
howtoplay = pygame.image.load("Space Blitz Sprites/howtoplay.png")
about = pygame.image.load("Space Blitz Sprites/about.png")
quit = pygame.image.load("Space Blitz Sprites/quit.png")

# inside main menu
instruction = pygame.image.load("Space Blitz Sprites/instruction.png")
back = pygame.image.load("Space Blitz Sprites/back.png")
aboutdev = pygame.image.load("Space Blitz Sprites/aboutdev.png")

# main menu music
music = pygame.mixer.music.load("Space Blitz Sprites/mountaintrails.mp3")

# PlayerSpriteMovement
playerimg = pygame.image.load("Space Blitz Sprites/spaceship.png")
playerX = 250
playerY = 400
velocity = 3
clock = pygame.time.Clock()

# Bullet
bulletimg = pygame.image.load("Space Blitz Sprites/bullet.png")
bulletX = 0
bulletY = playerY
bulletx_change = 0
bulletY_change = 8
bullet_state = "ready"
bullet_ammo = 5
bulletfont = pygame.font.Font('freesansbold.ttf', 16)
# Ammo Box
ammoboximg = pygame.image.load('Space Blitz Sprites/ammo.png')
ammoboxX = random.randint(0,468)
ammoboxY = random.randint(-1000,-800)
ammoboxY_change = -1.5

# Asteroid
asteroidimg = []
asteroidX = []
asteroidY = []
asteroidX_change = []
asteroidY_change = []
no_of_enemies = 40

def mainmenu():
    global menuselect
    global spaceblitz
    menu = True
    pygame.mixer.music.play(50)
    pygame.mixer.music.set_volume(0.2)
    while menu:
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                pygame.quit()
            if event.type == pygame.MOUSEBUTTONDOWN:
                if event.button == 1:
                    pos = pygame.mouse.get_pos()
                    if start.collidepoint(pos):
                        menu = False
                        menuselect = 1
                        pygame.mixer.music.stop()
                    if controls.collidepoint(pos):
                        menu = False
                        menuselect = 2
                        pygame.mixer.music.stop()
                    if developer.collidepoint(pos):
                        menu = False
                        menuselect = 3
                        pygame.mixer.music.stop()
                    if exit.collidepoint(pos):
                        menu = False
                        menuselect = 4

        display.fill((0, 0, 0))
        display.blit(spaceblitz, (170,150))
        start = display.blit(play, (170,250))
        controls = display.blit(howtoplay, (170,300))
        developer = display.blit(about, (170,350))
        exit = display.blit(quit, (170,400))
        pygame.display.flip()
        pygame.display.update()

def controls():
    global menuselect
    global menu
    controls = True
    while controls:
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                pygame.quit()
                quit()
            if event.type == pygame.MOUSEBUTTONDOWN:
                if event.button == 1:
                    pos = pygame.mouse.get_pos()
                    if balik.collidepoint(pos):
                        controls = False
                        menu = True
                        menuselect = 0
        balik = display.blit(back, (0,450))
        display.blit(instruction, (0,0))
        pygame.display.flip()
        pygame.display.update()
        display.fill((0, 0, 0))

def developers():
    global menuselect
    global menu
    dev = True
    while dev:
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                pygame.quit()
                quit()
            if event.type == pygame.MOUSEBUTTONDOWN:
                if event.button == 1:
                    pos = pygame.mouse.get_pos()
                    if balik.collidepoint(pos):
                        dev = False
                        menu = True
                        menuselect = 0
        balik = display.blit(back, (0, 450))
        display.blit(aboutdev, (0, 0))
        pygame.display.flip()
        pygame.display.update()
        display.fill((0, 0, 0))

# Asteroid
for r in range(no_of_enemies):
    asteroidimg.append(pygame.image.load("Space Blitz Sprites/asteroid.png"))
    asteroidX.append(random.randint(-100, 500))
    asteroidY.append(random.randint(-300, -30))
    asteroidX_change.append(0)
    asteroidY_change.append(2)




# Game Over Text
overfont = pygame.font.Font('freesansbold.ttf',32)


# Sprite image
def player(x, y):
    display.blit(playerimg, (x, y))

def fire_bullet(x, y):
    global bullet_state
    if bullet_ammo > -1:
        bullet_state = "fire"
        display.blit(bulletimg, (x + 9, y + -7))
    else:
        bullet_state = "ready"

def ammobox(x,y):
    display.blit(ammoboximg,(x,y))

def AmBoxCollision(ammoboxX,ammoboxY,playerX,playerY):
    ammoboxdistance = math.sqrt((math.pow(ammoboxX - playerX, 2)) + (math.pow(ammoboxY - playerY, 2)))
    if ammoboxdistance < 27:
        return True
    else:
        return False

def ammo():
    global bullet_ammo
    global ammo_decrease
    ammo_decrease = 1
    bullet_ammo -= ammo_decrease



def asteroid(x, y, r):
    display.blit(asteroidimg[r], (x, y))




def BulCollision(asteroidX, asteroidY, bulletX, bulletY):
    buldistance = math.sqrt((math.pow(bulletX - asteroidX, 2)) + (math.pow(bulletY - asteroidY, 2)))
    if buldistance < 27:
        return True
    else:
        return False
def PlayCollision(asteroidX, asteroidY, playerX, playerY):
    playdistance = math.sqrt((math.pow(playerX - asteroidX, 2)) + (math.pow(playerY - asteroidY, 2)))
    if playdistance < 27:
        return True
    else:
        return False
def gameover_screen():
    overtext = overfont.render("GAME OVER",True,(255,255,255))
    display.blit(overtext, (150,250))

# mainloop
def gamewindow():
    global menuselect
    global playerX
    global playerY
    global velocity
    global clock
    global bulletX
    global bulletY
    global bulletY_change
    global bullet_state
    global asteroidX
    global asteroidY
    global asteroidY_change
    global no_of_enemies
    global ammoboxX
    global ammoboxY
    global ammoboxY_change
    global dev
    global menu
    global bullet_ammo
    global ammo_decrease
    global passed_time
    font = pygame.font.Font(None, 54)
    font_color = pygame.Color('white')
    start_time = pygame.time.get_ticks()
    run_timer = True
    running = True

    while running:
        clock.tick(60)
        display.fill((0, 0, 0))
        AmmoBoxCollision = AmBoxCollision(ammoboxX,ammoboxY,playerX,playerY)
        if AmmoBoxCollision:
            ammoboxY = random.randint(-1000, -800)
            ammoboxX = random.randint(0, 468)
            if bullet_ammo <= 4 and bullet_ammo > -1:
                bullet_ammo += 1
            if bullet_ammo == -1:
                bullet_ammo +=2


        if bullet_ammo == -1 or bullet_ammo == 0:
            bullet_text = bulletfont.render("Ammo:%d" % bullet_ammo, True, (0, 0, 0))
            display.blit(bullet_text, (10, 468))
            noammo = bulletfont.render("NO AMMO",True,(255,255,255))
            display.blit(noammo,(10,468))
        else:
            bullet_text = bulletfont.render("Ammo:%d" % bullet_ammo, True, (255, 255, 255))
            display.blit(bullet_text, (10, 468))

        if bullet_state is "fire":
            fire_bullet(bulletX, bulletY)
            bulletY -= bulletY_change

        if bulletY <= 0:
            bulletY = playerY
            bullet_state = "ready"

        for r in range(no_of_enemies):
            asteroid(asteroidX[r], asteroidY[r], r)
            asteroidY[r] += asteroidY_change[r]
            if asteroidY[r] >= 500:
                asteroidY[r] = random.randint(-300, -30)
                asteroidX[r] = random.randint(-100, 500)

            Bulletcollision = BulCollision(asteroidX[r], asteroidY[r], bulletX, bulletY)
            if Bulletcollision:
                bulletY = playerY
                bullet_state = "ready"
                asteroidX[r] = random.randint(-100, 500)
                asteroidY[r] = random.randint(-300, -30)

            # Game over
            PlayerCollision = PlayCollision(asteroidX[r], asteroidY[r], playerX, playerY)

            if PlayerCollision:
                for j in range(no_of_enemies):
                    asteroidY_change[j] = 0
                    asteroidY[j] = random.randint(-300, -30)
                    asteroidX[j] = random.randint(-100, 500)
                    asteroidY_change[j] = 2

                velocity = 0
                bulletY_change = 0
                bulletY = 600
                ammoboxY_change = 0
                run_timer = False
                gameover_screen()
                playerX = 250
                playerY = 400
                velocity = 3


        # movement
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                pygame.quit()

            if event.type == pygame.MOUSEBUTTONDOWN:
                if event.button == 1:
                    pos = pygame.mouse.get_pos()
                    if balik.collidepoint(pos):
                        running = False
                        menu = True
                        menuselect = 0


            if event.type == pygame.KEYDOWN:
                if event.key == pygame.K_SPACE:
                    if bullet_ammo <= 5 and bullet_ammo > -1:
                        if bullet_state is "ready":
                            bulletX = playerX
                            bulletY = playerY
                            fire_bullet(bulletX, bulletY)
                            ammo()


        # player movement
        keys = pygame.key.get_pressed()
        if keys[pygame.K_LEFT]:
            playerX -= velocity

        if keys[pygame.K_RIGHT]:
            playerX += velocity

        if keys[pygame.K_DOWN]:
            playerY += velocity

        if keys[pygame.K_UP]:
            playerY -= velocity

        # Border
        if playerX <= 0:
            playerX = 0
        elif playerX >= 468:
            playerX = 468
        if playerY <= 0:
            playerY = 0
        elif playerY >= 468:
            playerY = 468

        if ammoboxY > 500:
            ammoboxY = random.randint(-1000,-800)
            ammoboxX = random.randint(0,468)
        ammobox(ammoboxX,ammoboxY)
        ammoboxY -= ammoboxY_change

        if run_timer:
            current_time = pygame.time.get_ticks()
            passed_time = current_time - start_time

        text = font.render(str(passed_time / 1000), True, font_color)
        display.blit(text, (50, 50))
        balik = display.blit(back, (350, 450))
        player(playerX, playerY)
        pygame.display.update()

mainmenu()
while True:
        if menuselect == 0:
            mainmenu()
        elif menuselect == 1:
            gamewindow()
        elif menuselect == 2:
            controls()
        elif menuselect == 3:
            developers()
        elif menuselect == 4:
            pygame.quit()

这是我想放置重置按钮的地方(在 PlayerCollision 或 balik.collidepoint(pos) 中)

        if PlayerCollision:
            for j in range(no_of_enemies):
                asteroidY_change[j] = 0
                asteroidY[j] = random.randint(-300, -30)
                asteroidX[j] = random.randint(-100, 500)
                asteroidY_change[j] = 2

            velocity = 0
            bulletY_change = 0
            bulletY = 600
            ammoboxY_change = 0
            run_timer = False
            gameover_screen()
            playerX = 250
            playerY = 400
            velocity = 3


    # movement
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()

        if event.type == pygame.MOUSEBUTTONDOWN:
            if event.button == 1:
                pos = pygame.mouse.get_pos()
                if balik.collidepoint(pos):
                    running = False
                    menu = True
                    menuselect = 0


        if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_SPACE:
                if bullet_ammo <= 5 and bullet_ammo > -1:
                    if bullet_state is "ready":
                        bulletX = playerX
                        bulletY = playerY
                        fire_bullet(bulletX, bulletY)
                        ammo()

如果我问了很多问题，我很抱歉。这是我用 Python 编写的第一个代码(或一般的编程)，所以我真的不知道大多数东西是如何工作的。另外，代码是我的代码和我的队友的代码的混合，所以这个程序中的一半代码对我来说是陌生的。非常感谢有关 future 编码实践的提示，但我现在只想完成我的游戏，所以我想完成我遇到的当前(也是最后一个)问题。

Answer 1

正如您所说，您刚刚开始并正在学习。非常好!您刚刚遇到了一个可以从中学到很多东西的问题:添加新功能 .一般来说，这个问题更适合 code review stack exchange但我认为它也适合这里。

那么问题究竟出在哪里呢？你说你想让你的游戏“回到”主菜单。你提出了一个(我发现)难以遵循的实现，并跟进了一堆我确信有效但很难(对我来说)阅读的代码。老实说，我发现您能够写出多少令人印象深刻的东西，尤其是因为这是您第一次编码!

在我看来，您真正的问题不是如何“返回”，而是如何使您的代码可修复/可更新。非常值得学习的一课。您当前的代码难以更新有几个原因:

您的所有代码都在一个文件中，难以导航

您有全局变量，很难跟踪

您使用了许多难以更改/跟踪

的硬编码值。

为什么这是个问题？如果你想改变一些东西，你找不到在哪里改变什么，因为你找不到任何东西，因为到处都是代码。然后，一旦找到它，由于全局变量，您无法真正了解所有内容。最后，硬编码值使您无法知道您是否已修复所有内容，或忘记了导致错误的数字(例如，您想将屏幕放大两倍，更改所有图片大小，但忘记更新速度)。

那么你如何改变这种情况呢？

好吧，首先尝试拆分您的代码，以便更轻松地查找内容。我喜欢把东西放在这样的文件夹中:

my_project/
    main.py
    .gitignore
    core/
        game_mechanics/
            player.py
            bullet.py
            asteroid.py
        game_setup/
            main_menu.py
            run_game.py
    config/
        config.yaml
    utils/
        read_config.py
    tests/
        test1.py
        test2.py

这可能看起来令人生畏，所以让我们超越一切:

Main.py :您运行的主文件。它看起来像这样:

from example_file import example_function

def main(config):
    while True:
        settings = main_menu()
        play_game(settings)

if __name__ == '__main__':
    config = load_config()
    main(config)

当您运行时 main.py它将加载配置，然后运行主要组件。这个文件应该很短，所以很容易理解发生了什么。例如，在这里，您可以通过运行 main_menu() 获得设置。然后使用这些设置玩游戏。当游戏退出时，主菜单再次显示。

接下来是 .gitignore 使用 git 时需要的文件。如果你不知道这是什么/你应该用谷歌搜索它，它会让你的生活更轻松。

在您的 核心文件夹中包含游戏特有的所有主要功能。这是您放置大部分代码的地方。将其拆分为逻辑文件很重要，这样您就可以轻松找到内容。

在您的 实用工具文件夹中，您有想要在项目之间共享的实用功能。

在您的 配置文件夹，您可以存储设置。这应该包含您使用的所有“数字或字母值”，这样您就不必通过代码手动更改任何地方的数字(并且可能忘记一个)，而是将其传递。

这解决了您必须找到什么地方的问题。一切都很好地订购，您可以轻松找到它。如果您想更改大型功能(如添加新菜单)，您可以在主文件中轻松完成此操作。

下一个问题是全局变量的使用。你有很多这样的值，这使得很难跟踪哪个值是什么。您可能很清楚，但想象一下，当您一年后回来并且值“随机”改变时，您如何找到变化的地方？

相反，尝试将内容传递给您的函数，如下所示:

def square_n(n):
    return n * n 

a = 5
a_squared = square_n(a)

这使得更容易阅读在哪里发生了什么。

最后，如前所述，硬编码值使所有内容都很难更新。以屏幕尺寸加倍为例。你把所有东西都放大了一倍，但忘记把一个速度分量加倍(因为你忽略了它)。这可能是一个“奇怪的错误”，需要一些时间来修复。相反，尝试将所有这些值保存在您的配置中，并如上所示传递它们。这看起来像这样:

def print_hello_world_n_times(n):
    for i in range(n):
        print("hello world")

config = load_config()
# config = {'a': 5, 'b': 10}
a = config['a']
print_hello_world_n_times(a)

很抱歉，我不会为您的问题提供复制粘贴解决方案。我认为对您来说，自己重新构造代码然后看看更改其功能要容易得多，这会更有用。

成功!