问题描述
我一直在尝试在 Python pygame 中创建稳定的降雨,但偶然发现了一个问题。当我不输入移动代码的部分时,雨滴网格没有问题。但是,当我添加运动时,网格消失了,那里只剩下一排移动的雨滴。看下面的代码:
import sys
import pygame
from pygame.sprite import Group
from settings import Settings
from raindrop import Raindrop
import game_functions as gf
def run_game():
# Initialize game and create a screen object.
pygame.init()
settings = Settings()
screen = pygame.display.set_mode((settings.screen_width,settings.screen_height))
pygame.display.set_caption("13-3")
# Make raindrop group.
raindrops = Group()
# Create the raindrops.
gf.create_raindrops(settings,screen,raindrops)
# Start the main loop for the game.
while True:
gf.update_raindrops(raindrops)
gf.update_screen(settings,raindrops)
# Watch for keyboard and mouse events.
for event in pygame.event.get():
if event.type == pygame.QUIT:
sys.exit()
run_game()
settings.py
class Settings():
"""A class to store all settings."""
def __init__(self):
"""Initialize the game's settings."""
# Screen settings
self.screen_width = 1200
self.screen_height = 800
self.bg_color = (0,255)
# Raindrop settings
self.raindrop_speed_factor = 1
game_functions.py
import sys
import pygame
from raindrop import Raindrop
def update_screen(settings,raindrops):
"""Update images on the screen and flip to the new screen."""
# Redraw the screen during each pass through the loop.
screen.fill(settings.bg_color)
raindrops.draw(screen)
# Make the most recently drawn screen visible.
pygame.display.flip()
def get_number_raindrops_x(settings,raindrop_width):
"""Determine the number of raindrops that fit in a row."""
available_space_x = settings.screen_width - 2 * raindrop_width
number_raindrops_x = int(available_space_x / (2 * raindrop_width))
return number_raindrops_x
def get_number_rows(settings,raindrop_height):
"""Determine the number of rows of raindrops that fit on the screen."""
available_space_y = settings.screen_height - (2 * raindrop_height)
number_rows = int(available_space_y / (2 * raindrop_height))
return number_rows
def create_raindrop(settings,raindrops,raindrop_number,row_number):
"""Create a raindrop and place it in the row."""
raindrop = Raindrop(settings,screen)
raindrop_width = raindrop.rect.width
raindrop.x = raindrop_width + 2 * raindrop_width * raindrop_number
raindrop.rect.x = raindrop.x
raindrop.rect.y = raindrop.rect.height + 2 * raindrop.rect.height * row_number
raindrops.add(raindrop)
def create_raindrops(settings,raindrops):
"""Create a full sky of raindrops."""
# Create a raindrop and find the number of raindrops in a row.
raindrop = Raindrop(settings,screen)
number_raindrops_x = get_number_raindrops_x(settings,raindrop.rect.width)
number_rows = get_number_rows(settings,raindrop.rect.height)
# Create the full sky of raindrops.
for row_number in range(number_rows):
for raindrop_number in range(number_raindrops_x):
create_raindrop(settings,row_number)
def update_raindrops(raindrops):
"""Update the positions of all raindrops in sky."""
raindrops.update()
雨滴.py
import pygame
from pygame.sprite import Sprite
class Raindrop(Sprite):
"""A class to represent a single raindrop in the sky."""
def __init__(self,settings,screen):
"""Initialize the raindrop and set its starting position."""
super(Raindrop,self).__init__()
self.screen = screen
self.settings = settings
# Load the raindrop image and set its rect attribute.
self.image = pygame.image.load('images/raindrop.png')
self.rect = self.image.get_rect()
# Start each new raindrop near the top left of the screen.
self.rect.x = self.rect.width
self.rect.y = self.rect.height
self.y = float(self.rect.y)
def update(self):
"""Move raindrop down."""
self.y += self.settings.raindrop_speed_factor
self.rect.y = self.y
def blitme(self):
"""Draw the raindrop at its current location."""
self.screen.blit(self.image,self.rect)
我知道对此的解决方案(来自不同的线程 - 感谢 gammazero)是改变这一点:
raindrop.rect.y = raindrop.rect.height + 2 * raindrop.rect.height * row_number
到:
raindrop.y = raindrop.rect.height + 2 * raindrop.rect.height * row_number
raindrop.rect.y = raindrop.y
我想知道原因,但找不到答案。谁能解释一下上面代码的变化实际上有什么不同,为什么突然起作用了?
解决方法
当您创建雨滴并将其 rect
的 y
设置到某个位置时,实际的 raindrop.y
会设置为某个默认值。 Raindrop.update()
使用 Raindrop.y
而不是 Raindrop.rect.y
来获取水滴的当前位置。替换代码所做的只是为 raindrop.y
分配一个适当的值,然后用于设置 raindrop.rect.y