Pygame - 如何更改和保持背景屏幕

编程问答 2022-05-28

问题描述

我使用的是 Python 3.6。

当我左键单击“开始游戏”矩形对象时，我试图让 Pygame 执行以下操作：

  1. 通过变量“background”将新背景图像从“bgHome”图像更改为“bgIntro”图像。
  2. 按住新的背景图像，松开鼠标左键时移除矩形对象。
  3. 显示文件“intro.txt”中的文本并保留位于变量 text1 中的页脚文本。

代码按预期工作，直到我松开鼠标左键，它恢复到前一个屏幕，实际上是 mainloop() 开头的标题屏幕。

我想我需要在左键单击操作后添加一些行来告诉 Pygame 鼠标按钮仍然按下？

完整代码如下：

# Imports
import sys
import os
import random
import time
import pygame
from pygame.locals import *

# Must add to initialize pygame
pygame.init()


#Colour chart
LIGHT_BLUE = (51,102,255)
BLUE = (0,255)
DARK_BLUE = (0,102)
LIGHT_RED = (255,65,65)
RED = (255,0)
DARK_RED = (153,0)
LIGHT_GREEN = (102,255,0)
GREEN = (51,153,0)
DARK_GREEN = (0,51,0)
WHITE = (255,255)
GREY = (102,102)
BLACK = (0,0)
YELLOW = (255,0)
ORANGE = (255,0)
PURPLE = (153,204)


#Other variables
res = (500,500)
screen = pygame.display.set_mode(res)
width = screen.get_width()
height = screen.get_height()
leftclick = (1,0)
middleclick = (0,1,0)
rightclick = (0,1)


#Backgrounds for game
background = pygame.image.load("bg1.png")
bgHome = pygame.image.load("bg1.png")
bgOptions = 0
bgIntro = pygame.image.load("bg2.png")
bgSimulate = 0
bgAssets = 0
bgEmpl = 0


#Setting up Fonts
smallfont = pygame.font.SysFont('Corbel',20)
mediumfont = pygame.font.SysFont('Corbel',32)
largefont = pygame.font.SysFont('Corbel',46)

#Common text featured throughout game
text1 = "Footer text goes here."
copyright_text = smallfont.render(text1,True,WHITE)


#Load text file
f = open('Intro.txt','r')
content = f.read()
intromsg = smallfont.render(content,BLACK)


#Set texts for buttons
start_butt_text = smallfont.render('Start Game',WHITE)
load_butt_text = smallfont.render('Load Game',WHITE)
quit_butt_text = smallfont.render('Quit Game',WHITE)


#Player class
class Player():
    def __init__(self,name):
        self.name = name
        self.cash = 10000
        self.assets = 0
        self.execs = 0
        self.mgmt = 0
        self.directlab = 0
        self.indirectlab = 0
        self.liab = 0
        self.equity = self.cash + self.assets - self.liab
        


#Create a white screen 
disPLAYSURF = pygame.display.set_mode((500,500))
disPLAYSURF.fill(WHITE)
pygame.display.set_caption("Capitalism: The Game")
    
    

def ButtonSG():
        pygame.draw.rect(screen,GREY,[10,10,140,40])
        pygame.draw.rect(screen,RED,[15,15,130,30]) 
        pygame.draw.rect(screen,60,BLACK,30])
        pygame.draw.rect(screen,110,115,30])


def ButtonLG():
        pygame.draw.rect(screen,30])
        
        
def ButtonQG():
        pygame.draw.rect(screen,30])
        
def ButtonNil():
        pygame.draw.rect(screen,30])  


def IntroScreen():
    disPLAYSURF.fill(WHITE)
    background = bgIntro
    disPLAYSURF.blit(background,(0,0))
    disPLAYSURF.blit(intromsg,(10,10))


#Game loop
def resetscreen():
    disPLAYSURF.blit(bgHome,0))


def mainloop():
    while True: 
                  
        background = pygame.image.load("bg1.png")
            
        # fills the screen with a color 
        
        disPLAYSURF.blit(background,0))
      
        # stores the (x,y) coordinates into 
        # the variable as a tuple 
        mouse = pygame.mouse.get_pos() 
      
        # if mouse is hovered on a button it changes colour
        if width-width+10 <= mouse[0] <= width-width+150 and height-height+10 <= mouse[1] <= height-height+50:
            ButtonSG()
        elif width-width+10 <= mouse[0] <= width-width+150 and height-height+60 <= mouse[1] <= height-height+100:
            ButtonLG() 
        elif width-width+10 <= mouse[0] <= width-width+150 and height-height+110 <= mouse[1] <= height-height+150:
            ButtonQG()
        else: 
            ButtonNil()
      
        # superimposing the text onto our button 
        screen.blit(start_butt_text,(35,22))
        screen.blit(load_butt_text,72)) 
        screen.blit(quit_butt_text,122))
        screen.blit(copyright_text,height-25)) 

              
        #checks if a mouse is clicked 
        if pygame.mouse.get_pressed() == (leftclick):
            if width-width+10 <= mouse[0] <= width-width+150 and height-height+10 <= mouse[1] <= height-height+50:
                IntroScreen()
            elif width-width+10 <= mouse[0] <= width-width+150 and height-height+60 <= mouse[1] <= height-height+100:
                pass
            elif width-width+10 <= mouse[0] <= width-width+150 and height-height+110 <= mouse[1] <= height-height+150:
                pygame.quit()
                sys.exit()
            else:
                pass
        
            screen.blit(copyright_text,height-25)) 


        for ev in pygame.event.get(): 
          
            if ev.type == pygame.QUIT: 
                pygame.quit()           

        # updates the frames of the game 
        pygame.display.update() 


mainloop()

解决方法

背景变量在主应用程序循环中连续设置。因此，如果您更改变量，它将在循环开始时重置。删除这行代码：

def mainloop():
    while True: 
                  
        # background = pygame.image.load("bg1.png") <--- DELETE

如果你想改变背景，你所要做的就是改变Background变量：

background = bgIntro

或

background = bgHome

请注意，如果您想在函数内部更改它，则必须使用 global statement，因为 background 是全局命名空间中的变量。见Using global variables in a function：

def clicked_start():
    global background
    
    background = bgIntro
    
    # [...]

点击检测未按预期工作。关于这个主题有很多问题和答案。例如：

pygamepython