python - 软件设计与开发专业 : Pygame Smudge Trails

Question

首先，我在网上和这个网站上搜索了解决方案，但我尝试过的解决方案都不起作用，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 和相应的兼容版本的 pygame 创建的。我还意识到一种更有效的方法是使用 sprite、sprite 组和“脏矩形”更新，但我无法转换程序，因此我将在没有这些功能的额外好处的情况下继续。

问题:留下“小行星”移动的污迹。
假设:背景被 blit 到屏幕上，但是小行星被 blit 到背景上。

请回复 - 顺便说一句，我是来自澳大利亚的高中生 :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。

您可以在draw 方法中将background 更改为screen。 这将解决它。

但按预期使用 Sprite 类确实值得。我对您的代码做了一些更改，以便为您切换。通过这些更改，它可以毫无痕迹地运行 :)

这里是变化和解释:

在顶部附近添加:

#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)

将此添加到小行星，__init__ 方法:

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

将此添加到 def move(self): 的末尾

        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 display 方法，因为它不再需要。

这也将比您之前的代码运行得更快，因为绘制某些东西所花费的时间与绘图区域的大小成正比，并且以前它每次都绘制整个背景 - 现在它只绘制 Sprite 和更改背景!

希望这有帮助:)