加载的图像序列闪烁，但仅有时出现（Pygame）

Question

First off, I have scoured the internet (including Stack Overflow) for an answer to my seemingly simple issue, but I have not found a fix that has worked for me. I am attempting to make a simple top down game in pygame, and all worked well until I added in a walking animation for the player. The animation is fine except that it flickers at certain points.

I have an idle animation for the player as well, but there is no flickering whatsoever. The idle animation has 2 frames, and the walking animations has 4, which brings me to suspect the problem lies within the number of frames.

Below I have pasted the code where I believe the problem lies along with this link ( https://imgur.com/P1CzyRX ) to a gif of the walking animation. If a zip file with the code and images would be best, I am more than happy to provide that as well. Lastly, I am aware that some of my coding habits are not the best, such as using global variables, so I hope anyone reading through my code isn't too bothered by that. Thank you so much, it means a lot!

class Player:
    def drawPlayer(self):
        global playerCounter, playerWalking

        if playerWalking == "false":
            if player1Facing == "front":
                player1.loopIdle(playerIdleFrontAnim)
            if player1Facing == "back":
                player1.loopIdle(playerIdleBackAnim)
            if player1Facing == "right":
                player1.loopIdle(playerIdleRightAnim)
            if player1Facing == "left":
                player1.loopIdle(playerIdleLeftAnim)

        elif playerWalking == "true":
            if player1Facing == "front":
                player1.loopWalking(playerWalkFrontAnim)
            if player1Facing == "back":
                player1.loopWalking(playerWalkBackAnim)
            if player1Facing == "right":
                player1.loopWalking(playerWalkRightAnim)
            if player1Facing == "left":
                player1.loopWalking(playerWalkLeftAnim)

    def loopWalking(self, animation):
        global playerCounter, currentPlayerStance

        if playerCounter <= playerWalkMax:
            screen.blit(animation[0], (player1X, player1Y))
            currentPlayerStance = "upright"
        elif (playerCounter > playerWalkMax) and (playerCounter < playerWalkMax * 2):
            screen.blit(animation[1], (player1X, player1Y))
            currentPlayerStance = "crouch"
        elif (playerCounter > (playerWalkMax * 2)) and (playerCounter < playerWalkMax * 3):
            screen.blit(animation[2], (player1X, player1Y))
            currentPlayerStance = "upright"
        elif playerCounter > playerWalkMax * 3:
            screen.blit(animation[3], (player1X, player1Y))
            currentPlayerStance = "crouch"
            if playerCounter >= playerWalkMax * 4:
                playerCounter = 0

        playerCounter += 1

    def loopIdle(self, animation):
        global playerCounter, currentPlayerStance

        if playerCounter <= playerIdleMax:
            screen.blit(animation[0], (player1X, player1Y))
            currentPlayerStance = "upright"
        elif playerCounter > playerIdleMax:
            screen.blit(animation[1], (player1X, player1Y))
            currentPlayerStance = "crouch"
            if playerCounter >= (playerIdleMax * 2):
                playerCounter = 0

        playerCounter += 1



player1 = Player()

done = 0
clock = pygame.time.Clock()
while not done:
    for event in pygame.event.get():

        if event.type == pygame.QUIT:
            done = 1

        elif event.type == pygame.KEYDOWN:
            player1XSpeed = 0
            player1YSpeed = 0
            if event.key == pygame.K_ESCAPE:
                done = 1
            elif event.key == pygame.K_LEFT:
                if player1Facing != "left":
                    player1Facing = "left"
                player1XSpeed = -player1SpeedVal
                playerWalking = "true"
            elif event.key == pygame.K_RIGHT:
                if player1Facing != "right":
                    player1Facing = "right"
                player1XSpeed = player1SpeedVal
                playerWalking = "true"
            elif event.key == pygame.K_UP:
                if player1Facing != "back":
                    player1Facing = "back"
                player1YSpeed = -player1SpeedVal
                playerWalking = "true"
            elif event.key == pygame.K_DOWN:
                if player1Facing != "front":
                    player1Facing = "front"
                player1YSpeed = player1SpeedVal
                playerWalking = "true"

        elif event.type == pygame.KEYUP:
            playerWalking = "false"
            if event.key == pygame.K_LEFT or event.key == pygame.K_RIGHT:
                player1XSpeed = 0
            elif event.key == pygame.K_UP or event.key == pygame.K_DOWN:
                player1YSpeed = 0

    # Update player1 movement
    player1X += player1XSpeed
    player1Y += player1YSpeed

    screen.fill(GRAY)
    if drawPlayer1 == "true":
        player1.loopWalking(playerWalkRightAnim)

    clock.tick(60)
    pygame.display.flip()

pygame.quit()

Answer 1

You're skipping some frames, 50 and 75. If playerCounter is 50, both of these conditions are False and you blit nothing.

elif (playerCounter > playerWalkMax) and (playerCounter < playerWalkMax * 2):
elif (playerCounter > playerWalkMax * 2) and (playerCounter < playerWalkMax * 3):

You can fix the code by checking if the playerCounter is <= playerWalkMax :

elif (playerCounter > playerWalkMax) and (playerCounter <= playerWalkMax * 2):
elif (playerCounter > playerWalkMax * 2) and (playerCounter <= playerWalkMax * 3):

---

I used some prints to figure out which frames were skipped:

def loopWalking(self, animation):
    global playerCounter
    if playerCounter <= playerWalkMax:
        screen.blit(animation[0], (player1X, player1Y))
        print('blit 0', end=' ')
    elif (playerCounter > playerWalkMax) and (playerCounter < playerWalkMax * 2):
        screen.blit(animation[1], (player1X, player1Y))
        print('blit 1', end=' ')
    elif (playerCounter > playerWalkMax * 2) and (playerCounter < playerWalkMax * 3):
        screen.blit(animation[2], (player1X, player1Y))
        print('blit 2', end=' ')
    elif playerCounter > playerWalkMax * 3:
        screen.blit(animation[3], (player1X, player1Y))
        if playerCounter >= playerWalkMax * 4:
            playerCounter = 0
        print('blit 3', end=' ')

    print(playerCounter)
    playerCounter += 1