球为什么不反弹?

本文介绍了球为什么不反弹?的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我正在制作一个简单的乒乓球游戏，但是当球从天花板上掉下来时，它不会来回弹跳.它只是从屏幕上消失.我无法弄清楚为什么会这样！我只关心球从屏幕的顶部和底部弹起，我希望它以直线路径来回弹跳.任何帮助表示赞赏！

I'm making a simple pong game, but when the ball drops from the ceiling, it doesn't bounce back and forth. It just goes off the screen. I can't figure out why this is happening! I am only concerned with the ball bouncing off the top and bottom of the screen and I want it to bounce back and forth in a straight path. Any help is appreciated!

我发现了问题！感谢大家的帮助！

I've found the problem! Thanks for all the help!

这是我的基本代码:

import math import random import sys, pygame from pygame.locals import * import ball import colors import paddle # draw the scene def draw(screen, ball1, paddle1) : screen.fill((128, 128, 128)) ball1.draw_ball(screen) paddle1.draw_paddle(screen) #function to start up the main drawing def main(): pygame.init() width = 600 height = 600 screen = pygame.display.set_mode((width, height)) ball1 = ball.Ball(300, 1, 40, colors.YELLOW, 0, 5) paddle1 = paddle.Paddle(250, 575, colors.GREEN, 100, 20) while 1: for event in pygame.event.get(): if event.type == QUIT: sys.exit() elif event.type == pygame.KEYDOWN: if event.key == pygame.K_RIGHT: paddle1.update_paddle('right', 20) if event.key == pygame.K_LEFT: paddle1.update_paddle('left', 20) ball1.test_collide_top_ball(600) ball1.test_collide_bottom_ball(0) ball1.update_ball() draw(screen, ball1, paddle1) pygame.display.flip() if __name__ == '__main__': main()

这是我的球类/方法代码:

And here is my code for the ball class/methods:

import pygame class Ball: def __init__(self, x, y, radius, color, dx, dy): self.x = x self.y = y self.radius = radius self.color = color self.dx = dx self.dy = dy def draw_ball(self, screen): pygame.draw.ellipse(screen, self.color, pygame.Rect(self.x, self.y, self.radius, self.radius)) def update_ball(self): self.x += self.dx self.y += self.dy def test_collide_top_ball(self, top_height): if (self.y >= top_height): self.dy *= -1 def test_collide_bottom_ball(self, coll_height): if (self.y >= coll_height): self.dy *= -1

推荐答案

您的测试碰撞函数返回速度值.你永远不会在任何地方使用它.

Your test collide functions return the value of velocity. You never use it anywhere.

您使用 dx=0 dy=5 调用更新球.

You call the update ball with dx=0 dy=5.

与其在碰撞后返回 a 值，不如将 dx 和 dy 保存在对象中.所以它会变成:

Instead of returning the a value after collision, it would be better to hold the dx and dy in the object. So it would become:

class Ball: def __init__(self, x, y, radius, color): self.x = x self.y = y self.radius = radius self.color = color self.dx = 0 self.dy = 5 def draw_ball(self, screen): pygame.draw.ellipse(screen, self.color, pygame.Rect(self.x, self.y, self.radius, self.radius)) def update_ball(self): self.x += self.dx self.y += self.dy def test_collide_top_ball(self, top_height): if (self.y >= top_height): self.dy *= -1 def test_collide_bottom_ball(self, coll_height): if (self.y >= coll_height): self.dy *= -1