How to get screen to clear?

[metulburr]

You have to set a flag and fill the screen every frame. Currently you are only filling the screen on the frame that a mouse button is down and the mouse is in collision with your student rect.

Here is an example that when you press a mouse button it switches to and from white.

import pygame as pg

pg.init()
screen = pg.display.set_mode((800,600))
running = True
bg_white = False


while running:
    for event in pg.event.get():
        if event.type == pg.QUIT:
            running = False
        elif event.type == pg.MOUSEBUTTONDOWN:
            bg_white = not bg_white
            
    if bg_white:
        screen.fill((255,255,255))
    else:
        screen.fill((0,0,0))
    pg.display.update()