Why Does My Pygame Ball Leave a Trail, and How Do I Fix It?

Moving the Ball in Pygame Instead of Leaving a Trail

When trying to move a ball in Pygame, you may encounter an issue where instead of moving, the ball stretches across the screen. This occurs because Pygame draws objects directly onto the display surface. Each frame, the entire surface must be cleared before redrawing objects.

To resolve this issue and properly move the ball, implement the following steps:

First, understand the typical Pygame application loop:

• Handle events using pygame.event.pump() or pygame.event.get().
• Update game states according to input events and time (frames).
• Clear the entire display or draw the background.
• Draw each object on the scene using the blit() method.
• Update the display surface using pygame.display.update() or pygame.display.flip().

In your code, you need to clear the display surface in each frame of the while loop. Add the following line to the beginning of the loop:

screen.fill(0)

Here's how the corrected code looks:

while True:

    screen.fill(0)

    main.draw_elements()
    main.move_ball()
    main.ball.x_pos += main.ball.speed
    pygame.display.flip()

This modification will ensure that the previous frame is cleared, allowing the ball to move correctly without leaving a trail behind.

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