python - 部分碰撞错误

Question

我目前正在尝试使用 pygame 制作 Pong 版本，但在检测球和 Racket 之间的碰撞时遇到一些问题。我对两个 Racket 都进行了检测，但我很快意识到，当球与 Racket 碰撞而没有球穿过时，左侧玩家无法移动 Racket 。右边的球员则没有这样的问题，保留左边的球员仍然可以让球正常反射。

import pygame, sys
from pygame.locals import *

pygame.init()
pygame.mixer.init()
pygame.font.init()

BLACK = (0, 0, 0)
WHITE = (255, 255, 255)

screenx = 1080
screeny = 720

clock = pygame.time.Clock()
for pygame.mouse.get_pos in (screenx, screeny):
    pygame.mouse.set_visible(False)


# Blueprint for creating player character
class Player:
    # Defines initial conditions for player
    def __init__(self):
        self.xpos = 0
        self.ypos = 0
        self.width = 20
        self.length = 100
        self.speed = 10
        self.move = 0
        self.upkey = 0
        self.downkey = 0
        self.score = 0
        self.rect = pygame.Rect((self.xpos, self.ypos, self.width, self.length))

    # if player character, defines paddle movement
    def player_move(self, key):
        if key[self.upkey]:
            self.ypos -= self.speed
            self.move = -1
        elif key[self.downkey]:
            self.ypos += self.speed
            self.move = 1
        else:
            self.move = 0

    # Creates screen boundary for players
    def player_boundary(self, key):
        if self.ypos == 0:
            self.speed = 0
            self.move = 0
            if key[self.downkey]:
                self.speed = 10
                self.move = -1
        elif self.ypos + self.length == screeny:
            self.speed = 0
            self.move = 0
            if key[self.upkey]:
                self.speed = 10
                self.move = 1

    # Draws player rectangle to surface
    def draw(self, surface):
        self.rect = pygame.draw.rect(surface, WHITE, (self.xpos, self.ypos, self.width, self.length))


# Blueprint for creating the ball
class Ball:
    def __init__(self):
        self.size = 15
        self.speed = 10
        self.vy = 0
        self.vx = 10
        self.ypos = screeny/2
        self.xpos = 100
        self.rect = pygame.Rect((self.xpos, self.ypos, self.size, self.size))

    # Defines movement of ball (in xy components)
    def ball_move(self):
        self.ypos += self.vy
        self.xpos += self.vx

    # method for ball bouncing off of player paddle **
    def ball_block(self, player):
        if player.move > 0:
            self.vy += player.speed * 0.3
            self.vx = -((self.speed**2 - self.vy**2) ** .5)
        elif player.move < 0:
            self.vy = player.speed * -0.3
            self.vx = -((self.speed**2 - self.vy**2) ** .5)
        elif player.move == 0:
            self.vx = -self.vx

    # for reflecting off of screen boundaries **
    def ball_reflect(self, screeny):
        if self.ypos == 0:
            self.vy = -self.vy
        elif self.ypos == screeny - self.size:
            self.vy = -self.vy

    # Method for detecting when player has scored
    def score(self):
        if self.xpos == 0:
            self.vx = -self.vx
            print ('Score')
        elif self.xpos == screenx - self.size:
            self.vx = -self.vx
            print ('Score')

    # Draws ball to surface
    def draw(self, surface):
        self.rect = pygame.draw.rect(surface, WHITE, (self.xpos, self.ypos,     self.size, self.size))

def setup():
    # Assigns values to player 1 (left side)
    player1 = Player()
    player1.xpos = 50
    player1.ypos = screeny/1.5
    player1.upkey = K_w
    player1.downkey = K_s

    # Assigns values to player 2 (right side)
    player2 = Player()
    player2.xpos = screenx - player2.width - 50
    player2.ypos = screeny/1.5
    player2.upkey = K_UP
    player2.downkey = K_DOWN

    return player1, player2

# Main loop of the game
def main():
    player1, player2 = setup()
    ball = Ball()
    play = True

    while play:
        for event in pygame.event.get():
            if event.type == QUIT:
                pygame.quit()
                sys.exit()

        key = pygame.key.get_pressed()
        if key[K_ESCAPE]:
            play = False

        if ball.rect.colliderect(player1):  # For some reason, ball can go through P1 while moving
            ball.ball_block(player1)
        elif ball.rect.colliderect(player2):
            ball.ball_block(player2)

        # Had issue with ball going through bottom, fixed by adding screeny to dependencies
        if ball.ypos == 0:
            ball.ball_reflect(screeny)
        elif ball.ypos == screeny - ball.size:
            ball.ball_reflect(screeny)

        player1.player_move(key)
        player2.player_move(key)
        ball.ball_move()

        # Calls methods for player boundaries and ball scoring
        player1.player_boundary(key)
        player2.player_boundary(key)
        ball.score()  # Ball will only score if colliding head on and not on P2's side

        # Draws objects to screen
        surface.fill(BLACK)
        player1.draw(surface)
        player2.draw(surface)
        ball.draw(surface)

        pygame.display.update()
        clock.tick(60)

# Sets up screen, calls main loop
surface = pygame.display.set_mode((screenx, screeny))
pygame.display.set_caption('PONG')

main()

据我所知，两个播放器的代码是相同的，但只有一个播放器按照我的预期方式工作。如有任何帮助，我们将不胜感激，并感谢您的宝贵时间。

编辑:通过向 ball_block 方法添加几行来修复

    def ball_block(self, player):
    if player.move > 0:
        self.vy += player.speed * 0.3
        if self.vx < 0:
            self.vx = ((self.speed**2 - self.vy**2) ** .5)
        elif self.vx > 0:
            self.vx = -((self.speed**2 - self.vy**2) ** .5)
    elif player.move < 0:
        self.vy = player.speed * -0.3
        if self.vx < 0:
            self.vx = ((self.speed**2 - self.vy**2) ** .5)
        elif self.vx > 0:
            self.vx = -((self.speed**2 - self.vy**2) ** .5)
    elif player.move == 0:
        self.vx = -self.vx

Answer 1

如果玩家在碰撞过程中移动，你总是在设置

self.vx = -((self.speed**2 - self.vy**2) ** .5)

所以它总是负数