python - 如何在Pygame中放入随机数

Question

import sys, pygame
import random
pygame.init()

x=0.5
speed = [x, x]
size = width, height = 800, 600
black = 0, 0, 0

screen = pygame.display.set_mode(size)

ball = pygame.image.load("intro_ball.gif")
ballrect = ball.get_rect()

Sair = True

while Sair:

    for event in pygame.event.get():
        if event.type == pygame.QUIT: Sair=False
    ballrect = ballrect.move(speed)
    if ballrect.left < 0 or ballrect.right > width:
        speed[0] = -speed[0]
        x=random.uniform(0, 1)
    if ballrect.top < 0 or ballrect.bottom > height:
        speed[1] = -speed[1]
        x=random.uniform(0, 1)

    screen.fill(black)
    screen.blit(ball, ballrect)
    pygame.display.flip()

sys.exit()

我预计球会移动，并且每次它碰到角落都会改变速度。

Answer 1

要使球移动，您必须使用可以存储浮点坐标的位置变量。根据速度，每帧都会更改位置。最后球矩形必须用位置更新:

pos = [0, 0]
while Sair:

    for event in pygame.event.get():
        if event.type == pygame.QUIT: Sair=False

    if ballrect.left < 0 or ballrect.right > width:
        x = random.uniform(0.1, 1)
        speed[0] = x if speed[0] < 0.0 else -x 

    if ballrect.top < 0 or ballrect.bottom > height:
        x = random.uniform(0.1, 1)
        speed[1] = x if speed[1] < 0.0 else -x  

    pos[0] += speed[0]
    pos[1] += speed[1]
    ballrect.topleft = (int(pos[0]), int(pos[1]))

    screen.fill(black)
    screen.blit(ball, ballrect)
    pygame.display.flip()

注意，坐标pygame.Rect是整数值。如果将小于 1 的正浮点值添加到整数值，则该值根本不会改变，因为结果会再次被截断为整数部分。

int a = 1
a + 0.5 == 1

确保随机速度始终大于 0.0。生成随机速度并根据新方向更改 speed:

例如

x = random.uniform(0.1, 1)
speed[0] = x if speed[0] < 0.0 else -x