pygame 不使用按键更新 draw.rect，即使 x 和 y 值正在更新

Question

我对编程还很陌生，我正在构建 Pong 只是一个初学者项目。我编写了以下代码来尝试移动两个桨，但是当按下 up/down/w/s 键时它们都不会移动。但是，在尝试自己调试时，我将其设置为将 x 和 y 值打印到控制台，以查看是否是问题所在，并且 x 和 y 值正在更新，但我的矩形坐标没有。我确信这是一个相当简单的修复，但我对编程很陌生，只是不知道出了什么问题。这是我的代码：

import time
pygame.init()
screenW = 800
screenH = 600
win = pygame.display.set_mode((screenW, screenH))
pygame.display.set_caption("Pong")
clock = pygame.time.Clock()
font = pygame.font.SysFont("comicsans", 20)
paddleW = 20
paddleH = 100
ballSpeed = 15

class paddle(object):
    def __init__(self, x, y, width, height):
        self.x = x
        self.y = y
        self.width = width
        self.height = height
        self.pad = (self.x, self.y, self.width, self.height)

    def draw(self, win):
        pygame.draw.rect(win, (255,255,255), self.pad)

class ball(object):
    def __init__(self, x, y, side):
        self.x = x
        self.y = y
        self.side = side
        self.pad = (self.x, self.y, self.side, self.side)

    def draw(self, win):
        pygame.draw.rect(win, (255,255,255), self.pad)

def redrawGameWindow():
    win.fill((0,0,0))
    paddleLeft.draw(win)
    paddleRight.draw(win)
    theBall.draw(win)
    pygame.display.update()



#Main Loop:
paddleLeft = paddle(10, screenH//2, paddleW, paddleH)
paddleRight = paddle(screenW - 10 - paddleW, screenH//2, paddleW, paddleH)
theBall = ball(screenW//2, screenH//2, 30)
run = True
while run:
    clock.tick(30)
    
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            run = False

    keys = pygame.key.get_pressed()

    if keys[pygame.K_UP]:
        print("left up")
        print(paddleRight.y)
        paddleRight.y -= ballSpeed

    elif keys[pygame.K_DOWN]:
        print("left down")
        print(paddleRight.y)
        paddleRight.y += ballSpeed

    elif keys[pygame.K_w]:
        print("right up")
        print(paddleLeft.y)
        paddleLeft.y -= ballSpeed

    elif keys[pygame.K_s]:
        print("right down")
        print(paddleLeft.y)
        paddleLeft.y += ballSpeed

    redrawGameWindow()


pygame.quit()

Answer 1

当您更改属性x 和y 时，列表pad 的内容不会发生神奇的变化。

您必须在绘图前更新.pad。例如：

class paddle(object):
    # [...]

    def draw(self, win):
        self.pad = (self.x, self.y, self.width, self.height)
        pygame.draw.rect(win, (255,255,255), self.pad)

无论如何，我建议使用pygame.Rect 对象而不是x、y、width 和height 属性：

class paddle(object):
    def __init__(self, x, y, width, height):
        self.rect = pygame.Rect(x, y, width, height)

    def draw(self, win):
        pygame.draw.rect(win, (255,255,255), self.rect)

class ball(object):
    def __init__(self, x, y, side):
        self.rect = pygame.Rect(x, y, side, side)

    def draw(self, win):
        pygame.draw.rect(win, (255,255,255), self.rect)

---

完整示例：

import pygame
import time
pygame.init()
screenW = 800
screenH = 600
win = pygame.display.set_mode((screenW, screenH))
pygame.display.set_caption("Pong")
clock = pygame.time.Clock()
font = pygame.font.SysFont("comicsans", 20)
paddleW = 20
paddleH = 100
ballSpeed = 15

class paddle(object):
    def __init__(self, x, y, width, height):
        self.rect = pygame.Rect(x, y, width, height)

    def draw(self, win):
        pygame.draw.rect(win, (255,255,255), self.rect)

class ball(object):
    def __init__(self, x, y, side):
        self.rect = pygame.Rect(x, y, side, side)

    def draw(self, win):
        pygame.draw.rect(win, (255,255,255), self.rect)

def redrawGameWindow():
    win.fill((0,0,0))
    paddleLeft.draw(win)
    paddleRight.draw(win)
    theBall.draw(win)
    pygame.display.update()


#Main Loop:
paddleLeft = paddle(10, screenH//2, paddleW, paddleH)
paddleRight = paddle(screenW - 10 - paddleW, screenH//2, paddleW, paddleH)
theBall = ball(screenW//2, screenH//2, 30)
run = True
while run:
    clock.tick(30)
    
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            run = False

    keys = pygame.key.get_pressed()

    if keys[pygame.K_UP]:
        print("left up")
        print(paddleRight.rect.y)
        paddleRight.rect.y -= ballSpeed

    elif keys[pygame.K_DOWN]:
        print("left down")
        print(paddleRight.rect.y)
        paddleRight.rect.y += ballSpeed

    elif keys[pygame.K_w]:
        print("right up")
        print(paddleLeft.rect.y)
        paddleLeft.rect.y -= ballSpeed

    elif keys[pygame.K_s]:
        print("right down")
        print(paddleLeft.rect.y)
        paddleLeft.rect.y += ballSpeed

    redrawGameWindow()


pygame.quit()