我怎样才能在屏幕上同时显示多个绘图而不闪烁？

Question

我目前正在为学校课程项目编写一个简单的电脑游戏，但在 pygame 中遇到了问题。在我的游戏中，玩家只需向空中飞行的目标射击，几乎是逆向太空入侵者。我当前的问题是，我不能在竞技场中同时拥有两个形状，而其中一个形状会闪烁和滞后。以下是我的代码，欢迎任何帮助。干杯。

另外，有谁知道我可以如何在每幅画之间添加延迟。正如我在上面暗示的那样，我的目标是让目标在没有重叠的情况下保持相当的空间，但我确实希望同时在屏幕上出现多个。干杯。

import pygame

#Setting window dimensions and caption (Module 1)

pygame.init()
window = pygame.display.set_mode((800, 575))
pygame.display.set_caption("TARGET PRACTICE")

#Colour variables (Module 1)

BLACK = (0, 0, 0)
WHITE = (255, 255, 255)
RED = (200, 0, 0)
GREEN = (0, 200, 0)
BLUE = (0, 0, 200)

#Target coordinates and dimensions (Module 3)

#target_x = 0
#target_y = 80
#target_w = 60
#target_h = 40
#target_v = 1

exec = True

class Target:
  def __init__(self, x, y, h, w, v):
    self.x = x
    self.y = y
    self.h = h
    self.w = w
    self.v = v

target_1 = Target(0, 80, 60, 40, 0.1)
target_2 = Target(0, 100, 60, 40, 0.1)
target_3 = Target(0, 50, 60, 40, 1)

clock = 0

while exec:
  pygame.time.delay(1)
  for event in pygame.event.get():
    if event.type == pygame.QUIT:
      exec = False

  #Target Movement (Module 4)

  window.fill(RED)

  #Background and target drawing (Module 2)

  target_1.x += target_1.v
  pygame.draw.rect(window, BLUE, (target_1.x, target_1.y, target_1.h, target_1.w))
  clock += 1

  if clock%2 == 0:
    target_2.x += target_2.v
    pygame.draw.rect(window, BLUE, (target_2.x, target_2.y, target_2.h, target_2.w))


  pygame.display.update()




pygame.quit()```

Answer 1

target_2 正在闪烁，因为它只是在每 2 帧中绘制一次。在每 2 帧更改 target_2 的位置，但在每一帧中绘制它：

while exec:
    # [...]

    # update positions 
    target_1.x += target_1.v
    if clock%2 == 0:
        target_2.x += target_2.v
    clock += 1

    # clear window (fill in rED)
    window.fill(RED)

    # draw all the objects of the scene in every frame 
    pygame.draw.rect(window, BLUE, (target_1.x, target_1.y, target_1.h, target_1.w))
    pygame.draw.rect(window, BLUE, (target_2.x, target_2.y, target_2.h, target_2.w))   

    # update display
    pygame.display.update()

注意，场景必须在每一帧中重新绘制。首先清除背景填充window.fill(RED)，然后绘制整个场景，最后更新显示（pygame.display.update()）。

---

如果你想延迟target_2，那么你必须在clock达到一定限制后绘制并更新位置：

clock = 0
target_2_threshold = 500

while exec:
    # [...]

    # update positions 
    clock += 1
    target_1.x += target_1.v
    if clock > target_2_threshold and clock % 2 == 0:
        target_2.x += target_2.v

    # clear window (fill in rED)
    window.fill(RED)

    # draw all the objects of the scene in every frame 
    pygame.draw.rect(window, BLUE, (target_1.x, target_1.y, target_1.h, target_1.w))
    if clock > target_2_threshold:
        pygame.draw.rect(window, BLUE, (target_2.x, target_2.y, target_2.h, target_2.w))   

    # update display
    pygame.display.update()