import pygame
pygame.init()

screen = pygame.display.set_mode((800, 600))
clock = pygame.time.Clock()

class Blob(pygame.sprite.Sprite):
    def __init__(self, x, y):
        super().__init__()
        self.images = []
        for i in range(1, 4):
            img = pygame.image.load(f'blob{i}.png').convert_alpha()
            self.images.append(img)

        self.index = 0
        self.image = self.images[self.index]
        self.rect = self.image.get_rect(center=(x, y))

        self.anim_counter = 0
        self.anim_speed = 10

    def update(self):
        self.anim_counter += 1
        if self.anim_counter >= self.anim_speed:
            self.anim_counter = 0
            self.index = (self.index + 1) % len(self.images)
            self.image = self.images[self.index]
            # Make sure center stays constant
            self.rect = self.image.get_rect(center=self.rect.center)

        print("Frame index:", self.index)

blob_group = pygame.sprite.Group()
blob_group.add(Blob(400, 300))

running = True
while running:
    screen.fill((30, 30, 30))
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False

    blob_group.update()
    blob_group.draw(screen)

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

pygame.quit()