软件设计与开发专业:Pygame Smudge Trails

Question

首先,我在网上搜索了这个网站的解决方案和我尝试过的那些都没有用,所以我决定发布我的个人问题和代码.该程序是使用Python 3.2.2和pygame的相应兼容版本创建的.我还意识到一个更有效的方法是使用精灵,精灵组和'脏矩形'更新,但我无法转换程序,所以我将继续没有这些功能的额外好处.

问题:"小行星"移动的污迹落后.
假设:背景在屏幕上显示,但小行星在背景上显示.

请回复 - 顺便说一句,我是AUS的高中生:D

import pygame
import random
import math
pygame.init()

height = 550
width = 750
screen = pygame.display.set_mode((width, height))
background = pygame.image.load("Planet.jpg")
Clock = pygame.time.Clock()


class asteroid(pygame.sprite.Sprite):
    def __init__(self, x, y, size):
        pygame.sprite.Sprite.__init__(self)
        self.x = x
        self.y = y
        self.size = 15
        self.speed = 0.0
        self.angle = 0
        self.colour = (171, 130, 255)
        self.thickness = 0

def display(self):
     pygame.draw.circle(background, self.colour, (int(self.x),int(self.y)), self.size, self.thickness)

     pygame.draw.circle(background, (255, 255, 255), (int(self.x),int(self.y)), self.size, 1)

def move(self):
    self.x += math.sin(self.angle) * self.speed
    self.y -= math.cos(self.angle) * self.speed

def boundaries(self):
    if self.x > width - self.size:
        self.x = 0 + self.size
    elif self.x < self.size:
        self.x = width - self.size
    if self.y > height - self.size:
        self.y = 0 + self.size
    elif self.y <self.size:
        self.y = height - self.size




num_target = 5
my_particles = []
num_particles = len(my_particles)
while num_particles < 5:
    for n in range(num_target):
        size = 20
        x = random.randint(size, height - size)
        y = random.randint(size, width - size)
        target = asteroid(x, y, size)
        target.speed = random.uniform(1.0, 1.0)
        target.angle = random.uniform(0, math.pi*2)
        my_particles.append(target)
        num_particles = num_particles + 1


def main():
    pygame.display.set_caption("Anyu's Game")
    screen.blit(background, (0,0))
    pygame.display.update()
    score = (pygame.time.get_ticks()/1000)
    print (score)


while True:
    pygame.display.update()
    screen.blit(background, (0,0))
    MouseP = pygame.mouse.get_pos()
    frames = Clock.get_fps
    pygame.mouse.set_visible
    score = (pygame.time.get_ticks()/1000)
    print (score)
    print (MouseP)
    for target in my_particles:
        target.move()
        target.boundaries()
        target.display()
        pygame.display.update()


    for event in pygame.event.get():

        if event.type == pygame.QUIT:
            pygame.quit();

if __name__=='__main__':
    main()

Answer 1

基本上，你是对的！圆圈直接绘制在背景上，每次绘制新圆圈时，旧圆圈都会保留。导致污迹/痕迹。

你可以在你的方法中更改background为。这会修复它。screendraw

Sprite但按预期使用这些类确实值得。我对您的代码进行了一些更改，以便为您切换。通过这些更改，它可以无踪迹地运行:)

以下是变更及说明：

将其添加到顶部附近：

#Create a new `pygame.Surface`, and draw a circle on it, then set transparency:
circle = pygame.Surface((30,30))
circle = circle.convert()
pygame.draw.circle(circle, (171, 130, 255), (int(15),int(15)), 15, 0)
circle.set_colorkey(circle.get_at((0, 0)), pygame.RLEACCEL)

将其添加到asteroid,__init__方法中：

#Sets the asteroid image, and then the asteroids co-ords (these are in `rect`)
        self.image = circle
        self.rect = self.image.get_rect()

将其添加到末尾def move(self):

        self.rect[0] = self.x
        self.rect[1] = self.y

改变：

my_particles = []

到：

#This is a special pygame container class, it has a draw() method that tracks changed areas of the screen.
my_particles = pygame.sprite.RenderUpdates()

改变：

my_particles.append(target)

到：

my_particles.add(target)

改变：

while True:
    pygame.display.update()
    screen.blit(background, (0,0))
    MouseP = pygame.mouse.get_pos()
    frames = Clock.get_fps
    pygame.mouse.set_visible
    score = (pygame.time.get_ticks()/1000)
    print (score)
    print (MouseP)
    for target in my_particles:
        target.move()
        target.boundaries()
        target.display()
        pygame.display.update()

到：

#initial screen draw:
screen.blit(background, (0,0))
pygame.display.update()
while True:
    #remove previous drawn sprites and replaces with background:
    my_particles.clear(screen, background)
    MouseP = pygame.mouse.get_pos()
    frames = Clock.get_fps
    pygame.mouse.set_visible
    score = (pygame.time.get_ticks()/1000)
    print (score)
    print (MouseP)
    for target in my_particles:
        target.move()
        target.boundaries()
    #draws changed sprites to the screen:
    pygame.display.update(my_particles.draw(screen))

删除该display方法，因为不再需要它。

这也将比您之前的代码运行得更快，因为绘制某些内容所需的时间与绘图区域的大小成正比，以前它每次都会绘制整个背景 - 现在它只绘制精灵并更改为的背景！