Why Aren't My PyGame Drawings Appearing?

Why You May Not Be Seeing Anything Drawn in PyGame

Although you are attempting to render objects in your PyGame application, the results may appear inconsistent or absent. To understand why this occurs, we need to recognize the distinction between drawing on a surface and updating the display.

Drawing on a Surface

In PyGame, you typically draw graphics onto a surface object. The screen you see in your application is actually a surface associated with the display. However, drawing on this surface alone does not make it visible in the actual display.

Updating the Display

To display the changes you make on the surface, you need to update the display. PyGame provides two primary methods for this:

• pygame.display.update(): Updates only a portion of the screen.
• pygame.display.flip(): Updates the entire display.

In your specific case, you have drawn a rectangle on the surface, but you have not updated the display. As a result, the changes remain invisible.

Typical PyGame Application Loop

A typical PyGame application follows a loop that includes:

• Event handling
• Game state updates
• Surface clearing
• Scene drawing
• Display update
• Frame rate limitation

Here's an example of an updated code that includes the necessary display update:

import pygame
from pygame.locals import *

pygame.init()

DISPLAY = pygame.display.set_mode((800, 800))
pygame.display.set_caption("Thing")
clock = pygame.time.Clock()

run = True
while run:
    # Handle events
    for event in pygame.event.get():
        if event.type == QUIT:
            run = False

    # Clear display
    DISPLAY.fill(0)

    # Draw scene
    pygame.draw.rect(DISPLAY, (200, 200, 200), pygame.Rect(0, 400, 800, 400))

    # Update display
    pygame.display.flip()

    # Limit frames per second
    clock.tick(60)

pygame.quit()
exit()

By incorporating the display update, you should now be able to see the drawn objects correctly in your application.

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