Pygame flashing scoreboard

Question

I am trying to add a flashing scoreboard, though I am not coming any further than creating colors and then put it in a list. I am assuming I could have problems with doing this while using font. How do I proceed?

import pygame
import sys

  


WIDTH = (660)
HEIGHT= (500)


RED = (255, 0, 0)
GREEN = (0, 255, 0)
BLUE = (0, 0, 255)

COLOR_LIST = [RED,GREEN,BLUE]

pygame.init()
screen = pygame.display.set_mode((WIDTH,HEIGHT))
pygame.display.set_caption("Pong Game")

score1 = 0
score2 = 0
WHITE = (255,255,255)

                
font = pygame.font.Font(None, 100)
text = font.render(str(score1), 1, WHITE)
screen.blit(text, (175, 20))
text = font.render(str(score2), 1, WHITE)
screen.blit(text, (525, 20))

pygame.display.flip()

Answer 1

You don't have an event-processing loop, so your application will simply exit.

Instead of pygame.display.flip(), you need something to handle the events, then paint the screen. For example:

# ... rest of code

while True:

    # Handle events
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            exit()

    # paint the screen
    screen.fill( (0,0,0 ) )  # paint it black
    screen.blit(text, (175, 20))
    screen.blit(text, (525, 20))   # Note: BUG, uses 'text' twice

    pygame.display.flip()

One way to implement flashing text, is to use a clock/timer mechanism that periodically changes the colour (or whether to paint) the text in question.

import pygame
import sys

WIDTH = 660
HEIGHT= 500


RED   = (255, 0, 0)
GREEN = (0, 255, 0)
BLUE  = (0, 0, 255)

COLOR_LIST = [RED,GREEN,BLUE]

pygame.init()
screen = pygame.display.set_mode((WIDTH,HEIGHT))
pygame.display.set_caption("Pong Game")

score1 = 0
score2 = 0
WHITE = (255,255,255)


font = pygame.font.Font(None, 100)
text1= font.render(str(score1), 1, WHITE)
text2= font.render(str(score2), 1, WHITE)

flashing_words  = "*Flash*"
flashing_text   = font.render( flashing_words, 1, WHITE )
next_flash_time = 0  # when is the next colour update
flash_colour    = 0     # what is the current flashing colour


while True:
    clock = pygame.time.get_ticks()   # time now

    # Handle events
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            exit()

    # paint the screen
    screen.fill( (0,0,0 ) )  # paint it black
    screen.blit(text1, (175, 20))
    screen.blit(text2, (525, 20))
    screen.blit(flashing_text, ( WIDTH//2, HEIGHT//2 ))

    # flashing text
    # Is it time to update the flashing text?
    if ( clock > next_flash_time ):
        # Set the time for the *next* flash
        next_flash_time = clock + 1000  # 1 second in the future
        # Change the colour
        flash_colour += 1
        if ( flash_colour >= len( COLOR_LIST ) ):
            flash_colour = 0  # loop around colour list
        # Re-make the text-bitmap in the new colour
        flashing_text = font.render( flashing_words, 1, COLOR_LIST[flash_colour] )

    pygame.display.flip()

The way the above code works is to set a time in the future from the current clock. So to do something every second, we make a variable:

time_now = pygame.time.get_ticks() 
time_in_future = time_now + MILLISECONDS_DELAY

The get_ticks() returns the time as a count of milliseconds (since program start). So by adding, say 1000, that's a time one second in the future. Now by comparing the variable we made with the current clock, we form a trigger:

time_now = pygame.time.get_ticks()
if ( time_now > time_in_future ):
    # Do some stuff

    # Reset my time_to_do_in_future to be in the future again
    # so this will trigger again in a second.        
    time_in_future = time_now + MILLISECONDS_DELAY

This is what the code example above is implementing. It makes a time-stamp for 1000 milliseconds in the future. When this time is past, it makes a new time-stamp, and also does some stuff.

In this case the some stuff, is to advance through the colour array, and use a new colour to re-render the text into a new bitmap. This makes it flash.