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Question

我想要的代码是这样，如果我按下某个键，手电筒颜色

pygame.draw.ellipse(gameDisplay, yellow,[375+lead_x,-43+lead_y,105,led]) 

变得更亮，如光yellow.Please assist.Here是完整的代码。

import pygame 
pygame.init() 
white = (34,34,34) 
black=(0,0,0) 
red=(255,0,0) 
led=45 
silver=(110,108,108) 
yellow=(193,206,104) 
yellow2=(213,230,100) 
gameDisplay = pygame.display.set_mode((800,600)) 
pygame.display.set_caption('Slither') 

gameExit=False 

myfont = pygame.font.SysFont("monospace", 15) 
lead_x = 300 
lead_y = 300 
background_color=black 
while not gameExit: 
    for event in pygame.event.get(): 
     if event.type == pygame.QUIT: 
      gameExit = True 
     if event.type == pygame.KEYDOWN: 
      if event.key == pygame.K_LEFT: 
       lead_x -= 10 
       print("LEFT") 

      if event.key == pygame.K_RIGHT: 
       lead_x +=10 
       print("RIGHT") 
      if event.key == pygame.K_UP: 
       lead_y -=10 
       print("UP") 
      if event.key == pygame.K_DOWN: 
       lead_y +=10 
       print("DOWN") 
      if event.key == pygame.K_a: 
       gameDisplay.fill(red) 
       led +=10 
      if led == 95: 
       background_color=red 
       print("YOU FOUND ME.NOW YOU WILL D I E") 
       background_color=red 

    gameDisplay.fill(background_color) 
    pygame.draw.ellipse(gameDisplay, black,[-295+300,-54+300,75,100]) 
    pygame.draw.ellipse(gameDisplay, red,[-285+300,-35+300,20,34]) 
    pygame.draw.ellipse(gameDisplay, red,[-255+300,-35+300,20,34]) 
    pygame.draw.rect(gameDisplay, silver,[470+lead_x,-35+lead_y,75,30]) 
    pygame.draw.ellipse(gameDisplay, yellow,[375+lead_x,-43+lead_y,105,led]) 


    pygame.display.update() 

pygame.quit() 
quit() 

Answer 1

的问题是，pygame的支持RGBA color values（- [R版，克颖，b略和的颜色的 lpha值），但不幸的是PyGames绘制功能don' t透明绘制（根据domcumanetaion）。

为了避免这个问题，你可以

1. 创建新的表面
2. 更改使用.set_alpha()
3. 它的Alpha值画出你的 “手电筒” 椭圆到新的表面
4. 将此表面切入主屏幕表面通过调用.blit()方法支持Alpha透明

这里是更新的程序：

# ... your code 

alpha = 0 

while not gameExit: 
    for event in pygame.event.get(): 
     if event.type == pygame.QUIT: 
      gameExit = True 

     if event.type == pygame.KEYDOWN: 
      #... your original code 

      if event.key == pygame.K_SPACE: 
       #change alpha value 
       alpha += 10 

    gameDisplay.fill(background_color) 

    pygame.draw.ellipse(gameDisplay, black,[-295+300,-54+300,75,100]) 
    pygame.draw.ellipse(gameDisplay, red,[-285+300,-35+300,20,34]) 
    pygame.draw.ellipse(gameDisplay, red,[-255+300,-35+300,20,34]) 


    alphaSurface = pygame.Surface((105,led)) # 1. 

    alphaSurface.set_alpha(alpha) # 2. 
    alphaSurface.fill(background_color) 

    pygame.draw.ellipse(alphaSurface, yellow,[0,0,105,led]) # 3. 
    gameDisplay.blit(alphaSurface, (375+lead_x,-43+lead_y)) # 4. 


    pygame.draw.rect(gameDisplay, silver,[470+lead_x,-35+lead_y,75,30]) 

    pygame.display.update() 

pygame.quit() 
quit() 

请注意，我们需要改变背景颜色和alphaSurface表面每次迭代的大小主循环的以获得预期的结果，这可能会减慢我们的游戏速度。

你也可以考虑使用pygame.HWSURFACE标志创建硬件加速的表面。看到PyGame documentation about surfaces以获取更多信息。