Question

我想在背景上保留一个图像让我们说一秒钟（或更多）然后它应该消失，我试图在一个函数内使用blit（image_draw）调用内部if语句，但图像出现的时间非常短时间，如果我改变函数image_draw内的图像的时间，我没有看到任何变化。

在代码中我有一条粗线连续向右和向左移动，每次触摸其中一个边框时，它会改变方向，当方向发生变化时会出现一个图像，我的问题是我怎么能控制背景图像的时间？函数image_draw没有帮助，这里是代码。

import pygame
import sys
import time
import math

from pygame.locals import *

def image_draw(IMAGE, RECT_FOR_IMAGE, IMAGE_TIME ):
    while IMAGE_TIME > 0:
        windowSurface.blit(IMAGE, RECT_FOR_IMAGE)
        IMAGE_TIME -= 1

pygame.init()

windowSurface = pygame.display.set_mode((300, 600), 0, 32)
pygame.display.set_caption("line and image")

WHITE = (255, 255, 255)
BLUE = (0, 0, 255)
GREEN = (0, 255, 0)
BLACK = (0, 0, 0)
MYCOLOR= (200, 240, 50)
OTHER_LINE_COLOR = (180, 0, 0)



OUR_LINE_START_X = 50
OUR_LINE_START_Y = 400
OUR_LINE_END_X = 250
OUR_LINE_END_Y = 400

OTHER_LINE_START_X = 0
OTHER_LINE_START_Y = 415
OTHER_LINE_END_X = 300
OTHER_LINE_END_Y = 415





IMAGE = pygame.image.load("cherry.png")
LEFT_IMAGE = 250
TOP_IMAGE = 530
WIDTH_IMAGE = 40
HIGHT_IMAGE = 40
IMAGE_TIME = 10
RECT_FOR_IMAGE_1 = pygame.Rect(LEFT_IMAGE, TOP_IMAGE, WIDTH_IMAGE, HIGHT_IMAGE)
RECT_FOR_IMAGE_2 = pygame.Rect(LEFT_IMAGE - 200, TOP_IMAGE, WIDTH_IMAGE, HIGHT_IMAGE)
SOUND = pygame.mixer.Sound("pickup.wav")

MOVE_SPEED = 1


DIRECTION = "left"



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



    if DIRECTION == "right" :
        OUR_LINE_START_X += MOVE_SPEED
        OUR_LINE_END_X += MOVE_SPEED

    elif DIRECTION == "left":
        OUR_LINE_START_X -= MOVE_SPEED
        OUR_LINE_END_X -= MOVE_SPEED

    if OUR_LINE_START_X < 0:
        DIRECTION = "right"
        SOUND.play()
        image_draw(IMAGE, RECT_FOR_IMAGE_1, IMAGE_TIME )


    if OUR_LINE_END_X > 300:
        DIRECTION = "left"
        SOUND.play()
        image_draw(IMAGE, RECT_FOR_IMAGE_2, IMAGE_TIME )




    pygame.draw.line(windowSurface, MYCOLOR, (OUR_LINE_START_X, OUR_LINE_START_Y), (OUR_LINE_END_X, OUR_LINE_END_Y), 30)
    pygame.draw.line(windowSurface, OTHER_LINE_COLOR, (OTHER_LINE_START_X, OTHER_LINE_START_Y), (OTHER_LINE_END_X, OTHER_LINE_END_Y), 3)
    pygame.display.update()
    time.sleep(0.02)

提前谢谢你。

Answer 1

你的while循环是游戏框架循环。

使用image_draw进行绘制时，您将在一帧内从10倒数到0，然后再将图像bl成。另外，因为您从具有相同名称的函数中引用IMAGE_TIME变量，所以变量的范围仅在该函数内。

对正在发生的事情的直观描述：

Game Loop:
  draw_image:
    10 - 0
      blit
  next frame

要使其正常工作，您可以将IMAGE_TIME变量保留在image_draw方法签名之外，并使用全局IMAGE_TIME。从image_draw中删除while循环并让它在每一帧上修改全局，然后当你想再次绘制图像时需要重置它。

IMAGE_TIME = 10

def image_draw(IMAGE, RECT_FOR_IMAGE):
  if IMAGE_TIME > 0:
    windowSurface.blit(IMAGE, RECT_FOR_IMAGE)
    IMAGE_TIME -= 1

# ... other code left out for brevity

if OUR_LINE_START_X < 0:
    DIRECTION = "right"
    SOUND.play()
    if IMAGE_TIME == 0:
      IMAGE_TIME = 10
    image_draw(IMAGE, RECT_FOR_IMAGE_1)


if OUR_LINE_END_X > 300:
    DIRECTION = "left"
    SOUND.play()
    if IMAGE_TIME == 0:
      IMAGE_TIME = 10
    image_draw(IMAGE, RECT_FOR_IMAGE_2)

值得指出的是，在pygame中控制帧率的适当方法是创建一个时钟对象并用所需的帧速率打勾：

clock = pygame.Clock()
while True:
  # do your stuff here
  clock.tick(60) # 60 frames per second

这意味着游戏循环每秒大约执行60次，因此您可以通过设置IMAGE_TIME = 60轻松控制图像的显示为1秒。

在pygame中将图像blit一段时间

1 个答案: