为什么我用 Pygame 制作的游戏会突然延迟几秒钟？

Question

我用 pygame 制作了一个 space 入侵者小游戏，我注意到游戏会周期性地滞后几秒钟。我不知道是什么问题。我是初学者。你能告诉我为什么会这样吗？有什么解决办法吗？

此外，为什么在主游戏循环中添加背景图像后一切都变慢了？

import pygame
from pygame import mixer
import random
import math

# Starting pygame
pygame.init()

# window
screen = pygame.display.set_mode((800, 600))
background = pygame.image.load('background.png')

# title and icon
pygame.display.set_caption("Space Invaders")
icon = pygame.image.load('icon.png')
pygame.display.set_icon(icon)

# background
mixer.music.load('galaxy.ogg')
mixer.music.play(-1)

# player
playerimg = pygame.image.load('rocket.png')
playerX = 370
playerY = 480
playerX_change = 0

# Enemy
enemy_img = []
enemyX = []
enemyY = []
enemyX_change = []
enemyY_change = []
num_of_enemies = 1

for i in range(num_of_enemies):
    enemy_img.append(pygame.image.load('Enemy.png'))
    enemyX.append(random.randint(0, 735))
    enemyY.append(random.randint(50, 300))
    enemyX_change.append(4)
    enemyY_change.append(40)

# Bullet
bulletimg = pygame.image.load('bullet.png')
bulletX = 0
bulletY = 480
bulletX_change = 0
bulletY_change = 10
bullet_state = "ready"

# ready = you can't see the bullet on the screen
# fire = the bullet is currently moving

# score
score_value = 0
font = pygame.font.Font('freesansbold.ttf', 32)

textX = 10
textY = 10

# gameover text
over_font = pygame.font.Font('freesansbold.ttf', 70)


def show_score(x, y):
    score = font.render("Score: " + str(score_value), True, (255, 255, 255))
    screen.blit(score, (x, y))


def game_over_text():
    over_text = over_font.render("GAME OVER!", True, (255, 0, 0))
    screen.blit(over_text, (200, 250))


def player(x, y):
    screen.blit(playerimg, (x, y))


def enemy(x, y, i):
    screen.blit(enemy_img[i], (x, y))


def fire_bullet(x, y):
    global bullet_state
    bullet_state = "fire"
    screen.blit(bulletimg, (x + 25, y + 10))


def iscollision(enemyX, enemyY, bulletX, bulletY):
    distance = math.sqrt(math.pow(enemyX - bulletX, 2) + math.pow(enemyY - bulletY, 2))
    if distance < 30:
        return True
    else:
        return False


# gameloop
running = True
while running:
    # RGB screen
    screen.fill((0, 0, 0))
    screen.blit(background, (0, 0))

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

        # Check keystroke left or right
        if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_LEFT:
                playerX_change = -10
            if event.key == pygame.K_RIGHT:
                playerX_change = 10
            if event.key == pygame.K_SPACE:
                if bullet_state is "ready":
                    bullet_sound = mixer.Sound('shoot.wav')
                    bullet_sound.play()
                    # gets the current x cor of the player
                    bulletX = playerX
                    fire_bullet(bulletX, bulletY)

        if event.type == pygame.KEYUP:
            if event.key == pygame.K_LEFT:
                playerX_change = 0
            if event.key == pygame.K_RIGHT:
                playerX_change = 0

    playerX += playerX_change

    if playerX <= 0:
        playerX = 0
    elif playerX >= 736:
        playerX = 736

    for i in range(num_of_enemies):

        # game over
        if enemyY[i] > 440:
            for j in range(num_of_enemies):
                enemyY[j] = 2000
            game_over_text()
            break

        enemyX[i] += enemyX_change[i]
        if enemyX[i] <= 0:
            enemyX_change[i] *= -1
            enemyY[i] += enemyY_change[i]
        elif enemyX[i] >= 736:
            enemyX_change[i] *= -1
            enemyY[i] += enemyY_change[i]

        # collision
        collision = iscollision(enemyX[i], enemyY[i], bulletX, bulletY)
        if collision:
            explosion_sound = mixer.Sound('explosion.wav')
            explosion_sound.play()
            bulletY = 480
            bullet_state = "ready"
            score_value += 1
            # print(score)
            enemyX[i] = random.randint(0, 735)
            enemyY[i] = random.randint(50, 300)

        enemy(enemyX[i], enemyY[i], i)

    # if enemyY <= 50:
    # enemyY_change *= -1
    # elif enemyY >= 300:
    # enemyY_change *= -1

    if bulletY <= 0:
        bulletY = 480
        bullet_state = "ready"

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

    player(playerX, playerY)
    show_score(textX, textY)
    pygame.display.update()

Answer 1

调用 convert() on the background image. That ensures that the image has the same pixel format as the display Surface and will help blit 以最佳性能运行：

screen = pygame.display.set_mode((800, 600))
background = pygame.image.load('background.png').convert()

请注意，如果表面的格式与显示器的格式不同，则 blit 必须在每一帧中即时转换格式。

为什么我用 Pygame 制作的游戏会突然延迟几秒钟？

Why does my game made with Pygame suddenly lag for a few seconds?

python

pygame

pygame-surface