Pygame程序执行错误

Question

我正在制作一个 pygame 程序来为精灵设置动画，但问题不是特定错误：

import sys
import os
import pygame
from pygame.locals import *

pygame.init ()

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

Surface = pygame.display.set_mode ((400, 400), 0, 32)
pygame.display.set_caption ('Animation Test')




class Processes (object):
    @staticmethod
    def load_image (imagefile):
        image = pygame.image.load (imagefile)   #Remember to call imagefile as a string statement

        return image, image.get_rect ()



class Sprite (pygame.sprite.Sprite):

    def __init__ (self):
        pygame.sprite.Sprite.__init__ (self)

        self.image, self.rect = Processes.load_image ('frame1.jpg')

        self.blindrect = pygame.Rect ((self.rect.top - 289, self.rect.left - 289), (self.rect.width, self.rect.height))




   def animation (self, key_event = None, mouse_event = None):

       blindpass = 0

       if key_event == K_LEFT:
       self.rect.centerx = self.rect.centerx - 10

       if key_event == K_RIGHT:
        self.rect.centerx = self.rect.centerx + 10

       if key_event == K_UP:
       self.rect.centery = self.rect.centery - 10

       if key_event == K_DOWN:
       self.rect.centery = self.rect.centery + 10


       if mouse_event == MOUSEBUTTONDOWN:
        self.rect.centerx, self.rect.centery = pygame.mouse.get_pos ()


    if blindpass > 0:

        if key_event == K_LEFT:
            self.blindrect.centerx = self.blindrect.centerx - 10

        if key_event == K_RIGHT:
            self.blindrect.centerx = self.blindrect.centerx + 10

        if key_event == K_UP:
            self.blindrect.centery = self.blindrect.centery - 10

        if key_event == K_DOWN:
            self.blindrect.centery = self.blindrect.centery + 10


        if mouse_event == MOUSEBUTTONDOWN:
            self.rect.centerx, self.rect.centery = pygame.mouse.get_pos () 




mecha = Sprite ()
allsprites = pygame.sprite.RenderPlain ((mecha, ))



while True:
Surface.fill (WHITE)

for event in pygame.event.get ():
    if event.type == KEYDOWN:
    mecha.animation (key_event = event.key)

    if event.type == MOUSEBUTTONDOWN:
    mecha.animation (mouse_event = event.type)

    if event.type == QUIT:
    pygame.quit ()
    sys.exit (0)



allsprites.draw (Surface)
pygame.display.update ((mecha.rect, mecha.blindrect))

现在，错误有点奇怪。输出是精灵确实出现在屏幕上，当我提供键和鼠标输入时它会移动，但问题是它会留下痕迹。这就是为什么我创建了一个矩形来跟踪精灵矩形，每次游戏循环时都应该用白色填充。但事实并非如此。至少，直到我最小化窗口并再次拉起它，所有的痕迹都消失了，背景变成了白色而不是黑色。但是当我移动图像时，轨迹又开始形成。我最小化，它们按预期消失了。

Answer 1

如果你的渲染函数这样做：

screen.fill(white)
# blit or sprite group drawing
pygame.display.flip()

它会将整个屏幕清除为白色，绘制一次精灵。不会有踪迹。

• 您的代码未正确粘贴。 f 就像您的 if QUIT 语句没有缩进一样，用于多语句。与 Sprite 类相同
• 如果您使用 Surface 或 Sprite 作为类/变量名称，您可能会遇到命名问题。

Answer 2

1. 您没有正确初始化和更新盲区。这就是为什么屏幕的正确部分没有更新并且您的精灵留下痕迹的原因。
2. 在您的更新循环中，由于您只更新显示更改的部分，因此您需要更新整个屏幕一次以在进入更新循环之前对其进行初始化。这就是屏​​幕最初不是白色的原因。

见下面更新的源码（只有 Sprite 类及以后被修改）：

class Sprite (pygame.sprite.Sprite):
    def __init__ (self):
        pygame.sprite.Sprite.__init__ (self)
        self.image, self.rect = Processes.load_image ('frame1.jpg')
        #initialize blindrect to be the same rectangle as rect
        self.blindrect = pygame.Rect ((self.rect.top, self.rect.left), (self.rect.width, self.rect.height))

    def animation (self, key_event = None, mouse_event = None):
        print(self.rect)
        print(self.blindrect)

        #save the current sprite position before moving the sprite
        self.blindrect.centerx = self.rect.centerx
        self.blindrect.centery = self.rect.centery

        if key_event == K_LEFT:
            self.rect.centerx = self.rect.centerx - 10

        if key_event == K_RIGHT:
            self.rect.centerx = self.rect.centerx + 10

        if key_event == K_UP:
            self.rect.centery = self.rect.centery - 10

        if key_event == K_DOWN:
            self.rect.centery = self.rect.centery + 10

        if mouse_event == MOUSEBUTTONDOWN:
            self.rect.centerx, self.rect.centery = pygame.mouse.get_pos ()

        print(self.rect)
        print(self.blindrect)

mecha = Sprite ()
allsprites = pygame.sprite.RenderPlain ((mecha, ))

#need to initially fill the entire surface with white
Surface.fill (WHITE)
pygame.display.update ((pygame.Rect((0,0),(400,400))))

while True:
    Surface.fill (WHITE)

    for event in pygame.event.get ():
        if event.type == KEYDOWN:
            mecha.animation (key_event = event.key)

        if event.type == MOUSEBUTTONDOWN:
            mecha.animation (mouse_event = event.type)

        if event.type == QUIT:
            pygame.quit ()
            sys.exit (0)

    allsprites.draw (Surface)
    #update only the previous sprite position and new sprite position
    pygame.display.update ((mecha.rect, mecha.blindrect))