Question

我一直在尝试在pygame中插入背景图像到python，我是pygame的初学者，我知道如何用pygame做一些简单的任务，但是，当我尝试将图像添加到背景时，我有点迷失在这上面，我一直在尝试将它应用于我在互联网上发现但没有运气的教程。这是代码：

import pygame, random, sys
from pygame.locals import *


TEXTCOLOR = (255, 255, 255)
screen = pygame.display.set_mode([1280, 780])
FPS = 60
BADDIEMINSIZE = 18
BADDIEMAXSIZE = 70
BADDIEMINSPEED = 2
BADDIEMAXSPEED = 12
ADDNEWBADDIERATE = 1
PLAYERMOVERATE = 3

def terminate():
    pygame.quit()
    sys.exit()

def waitForPlayerToPressKey():
    while True:
        for event in pygame.event.get():
            if event.type == QUIT:
                terminate()
            if event.type == KEYDOWN:
                if event.key == K_ESCAPE: # pressing escape quits
                    terminate()
                return

def playerHasHitBaddie(playerRect, baddies):
    for b in baddies:
        if playerRect.colliderect(b['rect']):
            return True
    return False

def drawText(text, font, surface, x, y):
    textobj = font.render(text, 1, TEXTCOLOR)
    textrect = textobj.get_rect()
    textrect.topleft = (x, y)
    surface.blit(textobj, textrect)

# set up pygame, the window, and the mouse cursor
pygame.init()
mainClock = pygame.time.Clock()
windowSurface = pygame.display.set_mode((WINDOWWIDTH, WINDOWHEIGHT))
pygame.display.set_caption('Dodger')
pygame.mouse.set_visible(False)

# set up fonts
font = pygame.font.SysFont(None, 48)

# set up sounds
gameOverSound = pygame.mixer.Sound('gameover.wav')


# set up images
playerImage = pygame.image.load('player.png')
playerRect = playerImage.get_rect()
baddieImage = pygame.image.load('baddie.png')
background_image = pygame.image.load("background.png") .convert()

# Copy image to screen
screen.blit(background_image, background_position)

# show the "Start" screen
drawText('Dodger', font, windowSurface, (WINDOWWIDTH / 3), (WINDOWHEIGHT / 3))
drawText('Press a key to start.', font, windowSurface, (WINDOWWIDTH / 3) - 30, (WINDOWHEIGHT / 3) + 50)
pygame.display.update()
waitForPlayerToPressKey()


topScore = 0
while True:
    # set up the start of the game
    baddies = []
    score = 0
    playerRect.topleft = (WINDOWWIDTH / 2, WINDOWHEIGHT - 50)
    moveLeft = moveRight = moveUp = moveDown = False
    reverseCheat = slowCheat = False
    baddieAddCounter = 0


    while True: # the game loop runs while the game part is playing
        score += 1 # increase score

        for event in pygame.event.get():
            if event.type == QUIT:
                terminate()

            if event.type == KEYDOWN:
                if event.key == ord('z'):
                    reverseCheat = True
                if event.key == ord('x'):
                    slowCheat = True
                if event.key == K_LEFT or event.key == ord('a'):
                    moveRight = False
                    moveLeft = True
                if event.key == K_RIGHT or event.key == ord('d'):
                    moveLeft = False
                    moveRight = True
                if event.key == K_UP or event.key == ord('w'):
                    moveDown = False
                    moveUp = True
                if event.key == K_DOWN or event.key == ord('s'):
                    moveUp = False
                    moveDown = True

            if event.type == KEYUP:
                if event.key == ord('z'):
                    reverseCheat = False
                    score = 0
                if event.key == ord('x'):
                    slowCheat = False
                    score = 0
                if event.key == K_ESCAPE:
                        terminate()

                if event.key == K_LEFT or event.key == ord('a'):
                    moveLeft = False
                if event.key == K_RIGHT or event.key == ord('d'):
                    moveRight = False
                if event.key == K_UP or event.key == ord('w'):
                    moveUp = False
                if event.key == K_DOWN or event.key == ord('s'):
                    moveDown = False

            if event.type == MOUSEMOTION:
                # If the mouse moves, move the player where the cursor is.
                playerRect.move_ip(event.pos[0] - playerRect.centerx, event.pos[1] - playerRect.centery)

        # Add new baddies at the top of the screen, if needed.
        if not reverseCheat and not slowCheat:
            baddieAddCounter += 1
        if baddieAddCounter == ADDNEWBADDIERATE:
            baddieAddCounter = 0
            baddieSize = random.randint(BADDIEMINSIZE, BADDIEMAXSIZE)
            newBaddie = {'rect': pygame.Rect(random.randint(0, WINDOWWIDTH-baddieSize), 0 - baddieSize, baddieSize, baddieSize),
                        'speed': random.randint(BADDIEMINSPEED, BADDIEMAXSPEED),
                        'surface':pygame.transform.scale(baddieImage, (baddieSize, baddieSize)),
                        }

            baddies.append(newBaddie)

        # Move the player around.
        if moveLeft and playerRect.left > 0:
            playerRect.move_ip(-1 * PLAYERMOVERATE, 0)
        if moveRight and playerRect.right < WINDOWWIDTH:
            playerRect.move_ip(PLAYERMOVERATE, 0)
        if moveUp and playerRect.top > 0:
            playerRect.move_ip(0, -1 * PLAYERMOVERATE)
        if moveDown and playerRect.bottom < WINDOWHEIGHT:
            playerRect.move_ip(0, PLAYERMOVERATE)

        # Move the mouse cursor to match the player.
        pygame.mouse.set_pos(playerRect.centerx, playerRect.centery)

        # Move the baddies down.
        for b in baddies:
            if not reverseCheat and not slowCheat:
                b['rect'].move_ip(0, b['speed'])
            elif reverseCheat:
                b['rect'].move_ip(0, -5)
            elif slowCheat:
                b['rect'].move_ip(0, 1)

         # Delete baddies that have fallen past the bottom.
        for b in baddies[:]:
            if b['rect'].top > WINDOWHEIGHT:
                baddies.remove(b)

        # Draw the game world on the window.
        windowSurface.fill(BACKGROUNDCOLOR)

        # Draw the score and top score.
        drawText('Score: %s' % (score), font, windowSurface, 10, 0)
        drawText('Top Score: %s' % (topScore), font, windowSurface, 10, 40)

        # Draw the player's rectangle
        windowSurface.blit(playerImage, playerRect)

        # Draw each baddie
        for b in baddies:
            windowSurface.blit(b['surface'], b['rect'])

        pygame.display.update()

        # Check if any of the baddies have hit the player.
        if playerHasHitBaddie(playerRect, baddies):
            if score > topScore:
                topScore = score # set new top score
            break

        mainClock.tick(FPS)

    # Stop the game and show the "Game Over" screen.
    gameOverSound.play()

    drawText('You lose', font, windowSurface, (WINDOWWIDTH / 3), (WINDOWHEIGHT / 3))
    drawText('Press a key to play again.', font, windowSurface, (WINDOWWIDTH / 3) - 80, (WINDOWHEIGHT / 3) + 50)
    pygame.display.update()
    waitForPlayerToPressKey()

    gameOverSound.stop()

我知道WINDOWWIDTH没有定义错误是什么但是我坚持添加背景图片，我的目标是能够在我的示例游戏中插入背景图像。请帮我！我非常感谢对此的帮助。教程的链接是http://programarcadegames.com/index.php?chapter=bitmapped_graphics_and_sound。

Answer 1

您必须在mainloop（blit）

中使用while True背景图片

你可以用它来代替

    # Draw the game world on the window.
    windowSurface.fill(BACKGROUNDCOLOR)

（从屏幕中删除所有元素）。

所以你得到：

    # Draw the game world on the window.
    screen.blit(background_image, background_position)

    # Draw the score and top score.
    drawText('Score: %s' % (score), font, windowSurface, 10, 0)

顺便说一下：你忘了给background_position赋值。

您在11.5 Full Listing

的教程中掌握了所有这些信息

Answer 2

您只显示一次背景图像。如果你将这行代码放入while循环中，它会在每个循环中显示该图像，修复你的问题，但为了防止将来出现任何问题，你需要使用以下步骤：

每个循环（这适用于所有代码，而不仅仅是您的代码），请执行以下步骤：

删除屏幕（使用“screen.fill（color）”）
显示背景图片（使用 “screen.blit（loaded_background_image，[0,0]）”，[0,0]可以替换使用不同的值来移动背景位置）
显示其他图像（订单很重要！使用 “screen.blit（LOADED_IMAGE，[X，Y]）”）
更新屏幕（通常为“pygame.display.flip（）”）

显示背景图像和显示任何其他图像之间没有任何区别。只需确保首先显示背景图像，因为如果它是你最后一个表面，它会覆盖所有其他图像！

您可以使用网站https://www.pygame.org/docs/找到有关pygame的任何信息。

此外，始终将.convert_alpha（）添加到所有透明加载图像的末尾以减少延迟。例如：

baddieImage = pygame.image.load（'baddie.png'）。convert_alpha（）

玩得开心！

与背景图象的Python问题

2 个答案: