python - set_alpha - Pygame blanco rectángulo parpadeante con frecuencia específica

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Question

Soy estudiante en la universidad y tengo una pregunta específica.

Actualmente, muestro un rectángulo blanco en el centro de una ventana con pygame sobre un fondo negro. Pero en este momento me gustaría parpadear mi rectángulo blanco a una frecuencia específica, y es por eso que necesito ayuda.

Actualmente implemento eso:

import pygame, sys
from pygame.locals import *

def main():
    pygame.init()

    fenetre = pygame.display.set_mode((500,400),0,32)

    black=(0,0,0)
    white=(255,255,255)

    fenetre.fill(black)

    pygame.draw.rect(fenetre, white,(200,150,100,50))


    while True:
        for event in pygame.event.get():
            if event.type==QUIT:
                pygame.quit()
                sys.exit()
        pygame.display.update()

main()

Gracias por su comunidad de ayuda.

Answer 1

Hice algunas modificaciones a su código para adaptarlo a sus necesidades y lo probé.

El código

import pygame
import sys
import time
from pygame.locals import *

pygame.init()

fenetre = pygame.display.set_mode((500, 400), 0, 32)
black = (0, 0, 0)
white = (255, 255, 255)
clock = pygame.time.Clock()

frequency = 1


def main():

    while True:
        for event in pygame.event.get():
            if event.type == QUIT:
                pygame.quit()
                sys.exit()

        pygame.draw.rect(fenetre, black, (200, 150, 100, 50))
        pygame.display.update()
        time.sleep(frequency)
        pygame.draw.rect(fenetre, white, (200, 150, 100, 50))
        pygame.display.update()
        time.sleep(frequency)
        clock.tick(30)


main()

El resultado debe ser la rect que aparece cada 1 seg.

Answer 2

Método muy popular para controlar elementos es usar el tiempo.

Establece la hora del próximo estado de cambio y luego la compara con la hora actual. De esta forma, usted controla el objeto y no se detiene while True loop para cando otras cosas.

import pygame
import sys

# --- constants ---

BLACK = (  0,   0,   0)
WHITE = (255, 255, 255)

# --- main ---

def main():
    pygame.init()

    fenetre = pygame.display.set_mode((500, 400), 0, 32)

    # time in millisecond from start program 
    current_time = pygame.time.get_ticks()

    # how long to show or hide
    delay = 500 # 500ms = 0.5s

    # time of next change 
    change_time = current_time + delay
    show = True

    while True:
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                pygame.quit()
                sys.exit()

        # --- updates ---

        current_time = pygame.time.get_ticks()

        # is time to change ?
        if current_time >= change_time:
            # time of next change 
            change_time = current_time + delay
            show = not show

        # --- draws ---

        fenetre.fill(BLACK)

        if show:
            pygame.draw.rect(fenetre, WHITE,(200,150,100,50))

        pygame.display.update()

main()

EDITAR: lo mismo con más elementos

import pygame
import sys

# --- constants ---

BLACK = (  0,   0,   0)
WHITE = (255, 255, 255)
RED   = (255,   0,   0)
GREEN = (  0, 255,   0)

# --- main ---

def main():
    pygame.init()

    fenetre = pygame.display.set_mode((500, 400), 0, 32)

    current_time = pygame.time.get_ticks()

    # time of show or hide
    delay = 500 # 500ms = 0.5s

    # time of next change (WHITE)
    change_time = current_time + delay
    show = True

    # time of next change (RED)
    red_change_time = current_time + delay + 150
    red_show = False

    # time of next change (GREEN)
    green_change_time = current_time + delay + 300
    green_show = False

    while True:
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                pygame.quit()
                sys.exit()

        # --- updates ---

        current_time = pygame.time.get_ticks()

        # is time to change ? (WHITE)
        if current_time >= change_time:
            change_time = current_time + delay
            show = not show

        # is time to change ? (RED)
        if current_time >= red_change_time:
            red_change_time = current_time + delay
            red_show = not red_show

        # is time to change ? (GREEN)
        if current_time >= green_change_time:
            green_change_time = current_time + delay
            green_show = not red_show

        # --- draws ---

        fenetre.fill(BLACK)

        if show: # (WHITE)
            pygame.draw.rect(fenetre, WHITE, (200,150,100,50))

        if red_show: # (RED)
            pygame.draw.rect(fenetre, RED, (100,150,100,50))

        if green_show: # (GREEN)
            pygame.draw.rect(fenetre, GREEN, (300,150,100,50))

        pygame.display.update()

main()

EDITAR: versión usando clase. Pero esta vez con diferentes frecuencias

import pygame
import sys

# --- constants ---

BLACK = (  0,   0,   0)
WHITE = (255, 255, 255)
RED   = (255,   0,   0)
GREEN = (  0, 255,   0)

# --- classes ---

class Rectangle():

    def __init__(self, color, rect, time, delay):
        self.color = color
        self.rect = rect
        self.time = time
        self.delay = delay
        self.show = False

    def draw(self, screen):
        if self.show:
            pygame.draw.rect(screen, self.color, self.rect)

    def update(self, current_time):
        if current_time >= self.time:
             self.time = current_time + self.delay
             self.show = not self.show

# --- main ---

def main():
    pygame.init()

    fenetre = pygame.display.set_mode((500, 400), 0, 32)

    current_time = pygame.time.get_ticks()

    # time of show or hide
    delay = 500 # 5000ms = 0.5s

    # objects    
    rect_white = Rectangle(WHITE, (200,150,100,50), current_time, 500)
    rect_red = Rectangle(RED, (100,150,100,50), current_time + 150, 100)
    rect_green = Rectangle(GREEN, (0, 0, 500, 400), current_time + 300, 2000)

    while True:
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                pygame.quit()
                sys.exit()

        # --- updates ---

        current_time = pygame.time.get_ticks()

        rect_white.update(current_time)
        rect_red.update(current_time)
        rect_green.update(current_time)

        # --- draws ---

        fenetre.fill(BLACK)

        rect_green.draw(fenetre)
        rect_white.draw(fenetre)
        rect_red.draw(fenetre)

        pygame.display.update()

main()