python - 如何将球反射到 Racket 上

Question

我第一次尝试 pygame，现在我已经非常熟悉 Python 作为一门语言，并且我一直在尝试重新创建 Pong，就像带有 2 个 Racket 和一个球的老式学校游戏一样。我似乎不知道如何让球从 Racket 上反射。我还没有在寻找角度之类的东西，因为我自己能够解决这个问题。

Buttt我想到的是得到一个坐标范围，即 Racket 的X和Y以及x和y+宽度和高度，如果球进入这些，它只是像在一个边界。我尝试过执行多个 if 语句，如下面的代码所示，但我也尝试过将其作为单个语句执行，但这不起作用。我没有实际打印任何调试打印，但是当我用 print 测试坐标范围时，它们看起来很好:D

我将我的代码粘贴到这里，以便你们可以按原样运行我的游戏。

我真的很感谢你们的帮助!

import pygame
pygame.init()
win = pygame.display.set_mode((500,500))
pygame.display.set_caption("First Game")

x = 50
y = 50
width = 10                                      #sets variables for the main paddle
height = 60
vel = 5

ballx = 250
bally = 250
radius = 5
direction = True                                #True is left, False is right                                                            
bvel = 4                                        #sets variables for the ball
angle = 0

coordxGT = 0
coordxLT = 0                                    #sets variables for the coordinate ranges of the first paddle for collision
coordyGT = 0
coordyLT = 0

def setCoords():
    coordxGT = x
    coordxLT = x + width
    coordyGT = y                                #This function updates the coords throughout the main loop
    coordyLT = y + height
    coordxLT += radius
    coordyLT += radius

run = True
while run == True:
    pygame.time.delay(20)
    for event in pygame.event.get():            #on quit, quit the game and dont throw up an error :)
        if event.type == pygame.QUIT:
            run = False
    setCoords()

    if direction == True:                       #Ball movement
        ballx -= bvel
    else:
        ballx += bvel

    if ballx<0:
        ballx += bvel
        direction = False
    elif bally<0:
        bally += bvel
    elif ballx>495:                             #if the ball hits an edge
        ballx -= bvel
        direction = True
    elif bally>495:
        bally -= bvel

    if ballx<coordxLT and ballx>coordxGT:
        print("S1")
        if bally<coordyLT and bally>coordyGT:                                   #THE PART I CANT FIGURE OUT. If the ball lands within these ranges of coordinates, reflect it and change its direction
            print("S2")
            if direction == True:
                print("YES")
                ballx += bvel
                direction = False

    keys = pygame.key.get_pressed()                         #gets the keys pressed at that current time

    if keys[pygame.K_DOWN]:
        bally += bvel                                       #Ball control (For debugging)
    if keys[pygame.K_UP]:
        bally -= bvel

    if keys[pygame.K_w]:
        y -= vel
    if keys[pygame.K_a]:
        x -= vel
    if keys[pygame.K_s]:                                    #Paddle controls
        y += vel
    if keys[pygame.K_d]:
        x += vel

    if x<0:
        x += vel
    if y<0:
        y += vel
    if x>80:
        x -= vel                                        #Stops the paddle from moving if it hits a boundary
    if y>440:
                                                        #440 because window height - height of cube
        y -= vel

    win.fill((0,0,0))
    pygame.draw.circle(win, (255, 255, 255), (ballx, bally), radius)      #refreshes the screen
    pygame.draw.rect(win,(255,255,255),(x, y, width, height))
    pygame.display.update()
pygame.quit()

Answer 1

您已经很接近了，但您错过了将变量 coordxGT、coordxLT、coordxLT、coordyLT 声明为是全局。

def setCoords():
    global coordxGT, coordxLT, coordxLT, coordyLT
    coordxGT = x
    coordxLT = x + width
    coordyGT = y  
    coordyLT = y + height
    coordxLT += radius
    coordyLT += radius

请注意，如果要写入函数中全局命名空间中的变量，则该变量已被解释为全局变量。否则，将在函数范围内创建并设置一个新变量。请参阅global statement .