How to Run Multiple While Loops Simultaneously in Pygame?

Running Multiple While Loops Simultaneously in Pygame

In Pygame, it's common to want to execute multiple tasks simultaneously. However, a common issue arises when attempting to run multiple while loops concurrently, as one loop might block others from executing. This article addresses this challenge and provides solutions to enable multiple loops to run smoothly.

Understanding the Conflict

In the provided code snippet, two while loops are used:

1. The main event processing loop (first while loop): This loop continuously checks for user input and updates the game state.
2. The face update loop (second while loop): This loop periodically updates the displayed face.

The issue occurs because the second loop contains a blocking operation (time.sleep()). This prevents the main event processing loop from running, potentially causing the program to become unresponsive.

Solution: Using Pygame's Time Measurement System

Replacing the blocking time.sleep() method with Pygame's time measurement system addresses the issue. Pygame provides a function, pygame.time.get_ticks(), which returns the number of milliseconds since Pygame's initialization. By using this function, it's possible to calculate and track the time intervals for the face update loop without blocking the other loops.

Example Code:

Here's a modified version of the code that employs these solutions:

<code class="python">import random
import pygame
import pygame.freetype

# Initialize pygame and game variables
face = ['^-^', '^v^', '◠◡◠', "'v'", '⁀◡⁀']
faceDisplay = pygame.freetype.Font('unifont.ttf', 100).render(random.choice(face), 1, (0, 255, 0))
screen = pygame.display.set_mode((800, 600))
run = True

# Variable used to track next face update time
next_render_time = 0

# Main game loop
while run:
    # Handle events (quit, keyboard input, etc.)
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            run = False

    # Calculate current time
    current_time = pygame.time.get_ticks()

    # Check if enough time has passed since the last face update
    if current_time >= next_render_time:
        # Update the displayed face and calculate the next update time
        faceDisplay = pygame.freetype.Font('unifont.ttf', 100).render(random.choice(face), 1, (0, 255, 0))
        next_render_time = current_time + random.randint(5, 10) * 1000  # Generate random time interval

    # Clear the screen, draw the updated face, and flip the display
    screen.fill((0, 0, 0))
    screen.blit(faceDisplay, (screen.get_width() // 2, screen.get_height() // 2))
    pygame.display.flip()</code>

By utilizing Pygame's time measurement system, this modified code allows the main event processing loop and the face update loop to operate concurrently without any interruptions.

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