Pygame Images won't load in after being called

Question

I've been trying to make Space Invaders using PyGame in Python and make a list for the enemy images, and I make a for loop twice to load the images in and append them to the lists; 2 times for 2 rows. Though, the only pictures that appear are the ones from the first for loop.

There are no errors either, so it seems it is working. I also checked to see if the two rows were overlapping each other, but from the way I tested it, I found that they weren't.

I made this before here without using OOP and now I'm using OOP to learn it better, and it isn't working properly, please help.

For Loops Below

EnemyRowBottom = EnemyClass()
EnemyRowTop = EnemyClass()

for i in range(EnemyRowBottom.numEnemies):
    EnemyImage1 = pygame.image.load('enemy.png') 
    EnemyRowBottom.EnemyImage.append( pygame.transform.scale(EnemyImage1, (70, 70)) )
    y = i * 10
    x = y * 10
    EnemyRowBottom.EnemyX.append( x ) 
    EnemyRowBottom.EnemyY.append( 150 )

for i in range(EnemyRowTop.numEnemies):
    EnemyImage1 = pygame.image.load('enemy.png') 
    EnemyRowTop.EnemyImage.append( pygame.transform.scale(EnemyImage1, (70, 70)) )
    y = i * 10
    x = y * 10
    EnemyRowTop.EnemyX.append( x ) 
    EnemyRowTop.EnemyY.append( 50 )

Full Code below

import pygame
import random
import math
from pygame import mixer
import time

# initialize pygame
pygame.init()

# create screen
screenX = 800
screenY = 800
screen = pygame.display.set_mode( (screenX, screenY) )

# background
background = pygame.image.load("background.jpg")

#sounds
mixer.music.load('bgMusic.mp3')
mixer.music.play(-1)

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

# score
scoreValue = 0
font = pygame.font.Font('freesansbold.ttf', 32)
textX = 10
textY = 10

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



# player 
PlayerImage = pygame.image.load('SpaceShip.png')
PlayerImage = pygame.transform.scale(PlayerImage, (84, 84))
playerX = 370
playerY = 650
xChangePlayer = 0

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

# check collision
def Collision(EX, EX2, EY, EY2, LX, LY):
    distance = math.sqrt((math.pow(EX - LX, 2) + math.pow(EY - LY, 2)))
    distance2 = math.sqrt((math.pow(EX2 - LX, 2) + math.pow(EY2 - LY, 2)))

    if distance <= 35:
        return 1
    elif distance2 <= 35:
        return 2

        
def DistanceEnemy(EX, EX2, EY, EY2):
    distance = math.sqrt((math.pow(EX2 - EX, 2) + math.pow(EY2 - EY, 2)))

    if distance <= 70:
        return True


# bottom line
Line = pygame.image.load('BottomLine.jpg')
LineX = 0
LineY = 655

def BottomLine(x, y):
    global Line
    screen.blit(Line, (x, y))

# Laser 
LaserImage = pygame.image.load('PlayerLaser.png')
LaserImage = pygame.transform.scale(LaserImage, (50, 50))
LaserX = random.randint(15, (screenX - 85) ) 
LaserY = 750
xLaserChange = 0
yLaserChange = 1

# can't see bullet on screen until Ready changes to Fire
LaserState = "Ready"

def Firelaser(x, y):
    global LaserState
    LaserState = "Fire"
    screen.blit(LaserImage, (x+17, y+10))


GameOverfont = pygame.font.Font('freesansbold.ttf', 82)

def GameOver():
    global GameOverfont
    text = GameOverfont.render("GAME OVER", True, (255, 255, 255))
    screen.blit(text, (140, 250))


# enemy
class EnemyClass:

    EnemyImage = []
    EnemyX = []
    EnemyY = []
    numEnemies = 4
    xEnemyChange = 0.2
    yEnemyChange = 50

        
    def enemyMovement(self, i):
        EnemyClass.EnemyX[i] += EnemyClass.xEnemyChange

        if EnemyClass.EnemyX[i] >= 736:
            EnemyClass.xEnemyChange = -EnemyClass.xEnemyChange
            for x in range(len(EnemyClass.EnemyY)):
                EnemyClass.EnemyY[x] += EnemyClass.yEnemyChange
        elif EnemyClass.EnemyX[i] <= 0:
            EnemyClass.xEnemyChange = .2
            for x in range(len(EnemyClass.EnemyY)):
                EnemyClass.EnemyY[x] += EnemyClass.yEnemyChange

    def enemy(self, i):
        screen.blit(EnemyClass.EnemyImage[i], (EnemyClass.EnemyX[i], EnemyClass.EnemyY[i]))

    def enemyGameOver(self, x, y):
        screen.blit(EnemyClass.EnemyImage[i], (x, y))

    def CollisionDetection(self, i, scoreValue, lasery, laserstate):
        global LaserY, LaserState
        ExplosionSound = mixer.Sound('explosion.wav')
        ExplosionSound.play()
        LaserY = lasery
        LaserState = laserstate
        scoreValue += 1

        # enemy respawn
        OldEnemyY = EnemyClass.EnemyY[i]
        EnemyClass.EnemyY[i] = -20

        if EnemyClass.EnemyY[i] >= OldEnemyY:
            EnemyClass.EnemyY[i] -= 40




EnemyRowBottom = EnemyClass()
EnemyRowTop = EnemyClass()

for i in range(EnemyRowBottom.numEnemies):
    EnemyImage1 = pygame.image.load('enemy.png') 
    EnemyRowBottom.EnemyImage.append( pygame.transform.scale(EnemyImage1, (70, 70)) )
    y = i * 10
    x = y * 10
    EnemyRowBottom.EnemyX.append( x ) 
    EnemyRowBottom.EnemyY.append( 150 )

for i in range(EnemyRowTop.numEnemies):
    EnemyImage1 = pygame.image.load('enemy.png') 
    EnemyRowTop.EnemyImage.append( pygame.transform.scale(EnemyImage1, (70, 70)) )
    y = i * 10
    x = y * 10
    EnemyRowTop.EnemyX.append( x ) 
    EnemyRowTop.EnemyY.append( 50 )





# game loop
running = True
while running:

    # setting background
    screen.fill( (0, 0, 0) )
    screen.blit(background, (0, 0))


    # make function that closes program when x pressed
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False

        # keystroke detection
        if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_LEFT:
                xChangePlayer = -0.4
            if event.key == pygame.K_RIGHT:
                xChangePlayer = +0.4
            if event.key == pygame.K_SPACE:
                if LaserState == "Ready":
                    LaserSound = mixer.Sound('shoot.wav')
                    LaserSound.play()
                    LaserX = playerX
                    LaserY = 600
                    Firelaser(LaserX, LaserY)
                    LaserY -= yLaserChange
        
        if event.type == pygame.KEYUP:
            if event.key == pygame.K_LEFT or event.key == pygame.K_RIGHT:
                xChangePlayer = 0


    # player movement 
    playerX += xChangePlayer

    # setting boudries for the player 
    if playerX < 0:
        playerX = 0
    elif playerX >= 736:
        playerX = 735




    # setting boudries for the enemy 
    for i in range(EnemyRowTop.numEnemies):

        BlitEnemy1 = EnemyRowTop.enemy(i)
        BlitEnemy2 = EnemyRowBottom.enemy(i)

        gameSoundPlayed = 0
        if EnemyRowTop.EnemyY[i] >= 600 or EnemyRowBottom.EnemyY[i] >= 600 and (gameSoundPlayed == 0):
            GameOver()
            BottomLine(LineX, LineY)
            player(playerX, playerY)
            show_score(textX, textY)
            pygame.display.update()
            gameSoundPlayed += 1
            EnemyRowTop.xEnemyChange = 0
            EnemyRowTop.yEnemyChange = 0
            EnemyRowBottom.xEnemyChange = 0
            EnemyRowBottom.yEnemyChange = 0
            mixer.music.stop()
            mixer.music.load('GameOverSound.wav')
            mixer.music.play()
            time.sleep(3)
            break

            
        EnemyRowTop.enemyMovement(i)
        EnemyRowBottom.enemyMovement(i)        


        # collision detection
        collision = Collision(EnemyRowTop.EnemyX[i], EnemyRowBottom.EnemyX[i], EnemyRowTop.EnemyY[i], EnemyRowBottom.EnemyY[i], LaserX, LaserY)
        if collision == 1:
            EnemyRowTop.CollisionDetection(i, scoreValue, 600, "Ready")

            EnemyDistance = DistanceEnemy(EnemyRowTop.EnemyX[i], EnemyRowBottom.EnemyX[i], EnemyRowTop.EnemyY[i], EnemyRowBottom.EnemyY[i])
            if EnemyDistance == True:
                EnemyClass.EnemyY[i] -= 50



        if collision == 2:
            EnemyRowBottom.CollisionDetection(i, scoreValue, 600, "Ready")

            EnemyDistance = DistanceEnemy(EnemyRowTop.EnemyX[i], EnemyRowBottom.EnemyX[i], EnemyRowTop.EnemyY[i], EnemyRowBottom.EnemyY[i])
            if EnemyDistance == True:
                EnemyClass.EnemyY[i] -= 50

        BlitEnemy1
        BlitEnemy2


    # laser movement
    if LaserY <= -20:
        LaserY = 750
        LaserState = "Ready"

    if LaserState == "Fire":
        Firelaser(LaserX, LaserY)
        LaserY -= yLaserChange


    # outputting characters
    BottomLine(LineX, LineY)
    player(playerX, playerY)
    show_score(textX, textY)
    
    
    pygame.display.update()

    if gameSoundPlayed == 1:
        break

You should take a look at classes again, especially the __init__ method. The class you use makes the program unnecessarily complex. — Jerry, Aug 02 '22 at 11:12
Please trim your code to make it easier to find your problem. Follow these guidelines to create a [minimal reproducible example](https://stackoverflow.com/help/minimal-reproducible-example). — Community, Aug 02 '22 at 14:59
Also dont load the same image more than once. Just save it in a global variable. — Jerry, Aug 02 '22 at 18:54

score 0 · Accepted Answer · answered Aug 02 '22 at 19:08

I cant test it but I think I found the problem. You should add a _init_ method to your EnemyClass. There you can define these variables so each row has its own lists of enemies. Because your enemies have the same image you dont need to load the image more than once.

EnemyImage = []
EnemyX = []
EnemyY = []
numEnemies = 4
xEnemyChange = 0.2
yEnemyChange = 50

class EnemyClass:
    EnemyImage = pygame.transform.scale(pygame.image.load('enemy.png'), (70, 70))

    def __init__(self):
        self.EnemyX = []
        self.EnemyY = []
        self.numEnemies = 4
        self.xEnemyChange = 0.2
        self.yEnemyChange = 50

EnemyRowBottom = EnemyClass()
EnemyRowTop = EnemyClass()

But it would make more sense to have an object for each enemy instead of the enemy rows.

score 0 · Answer 2 · answered Aug 03 '22 at 16:36

The problem of your code is, that the list containing the images in your EnemyClass is a class-attribute of your EnemyClass. As a result, every instance of that class accesses the same list of EnemyClass, and has not its own list in EnemyRowBottom and EnemyRowTop. You can fix this problem by making EnemyImage an object-attribute:

class EnemyClass:
    def __init__(self):
        self.EnemyImage = []
        self.EnemyX = []
        self.EnemyY = []
        self.numEnemies = 4
        self.xEnemyChange = 0.2
        self.yEnemyChange = 50

You can then access your images with "self.EnemyImage" inside the methods.

Moreover, to avoid the same image twice, you can put your pygame.image.load-method outside and before the loops, so that the game starts quicker.

Pygame Images won't load in after being called

2 Answers2