java - Java弹跳球墙

我试图理解这些代码：

    /*
 * File: BouncingBallWalls.java
 * ---------------------
 * This is exercise 15 in chapter 4 of "The Art and Science of Java."
 * It requires me to write a program that makes an animated bouncing
 * ball on the screen, bouncing off the window edges.
 */

import java.awt.*;
import acm.program.*;
import acm.graphics.*;

public class BouncingBallWalls extends GraphicsProgram {
    public void run() {
        GOval ball = new GOval (getWidth()/2 - BALL_SIZE/2, getHeight()/2 - BALL_SIZE, BALL_SIZE, BALL_SIZE);               /* Centers the ball */
        ball.setFilled(true);
        ball.setFillColor(Color.BLUE);
        ball.setColor(Color.BLUE);
        add(ball);
        double dx = (getWidth()/N_STEPS);
        double dy = (getWidth()/N_STEPS);
        while(true) {
            ball.move(dx, dy);                                   /* Movement for the ball */
            pause(PAUSE_TIME);
            if (ball.getY() > getHeight() - BALL_SIZE) {         /* Each "if" statement reverses the direction of the ball on one */
                dy = dy * -1;                                                         /* axis if it hits a boundry */
            }
            if(ball.getX() > getWidth()- BALL_SIZE) {
                dx = dx * -1;
            }
            if(ball.getY() < 0) {
                dy = dy * -1;
            }
            if(ball.getX() < 0) {
                dx = dx * -1;
            }
        }
    }
    private static final double N_STEPS = 1000;
    private static final double PAUSE_TIME = 2;
    private static final double BALL_SIZE = 50.0;
}

我了解以下内容，为什么将gameWidth除以N_STEPS？ N_STEPS是什么？

        double dx = (getWidth()/N_STEPS);
        double dy = (getWidth()/N_STEPS);

private static final double N_STEPS = 1000;

参考：http://tenasclu.blogspot.co.uk/2012/12/first-few-days-of-learning-to-program.html

最佳答案

将屏幕尺寸除以N_STEPS即可得到dx和dy，它们表示您希望球在每个循环中移动的距离。 N_STEPS根据可用的屏幕宽度来定义移动，以便无论屏幕大小如何，相对移动/速度都是相同的。

查看N_STEPS的另一种方法是，它控制球的平滑度和速度。这样做的方式可以使平滑度和速度保持一致，而与屏幕大小无关。较高的N_STEPS将导致每个循环的球运动更平滑/更慢。

请注意您的代码：

double dx = (getWidth()/N_STEPS);
double dy = (getWidth()/N_STEPS);

应该可能是：

double dx = (getWidth()/N_STEPS);
double dy = (getHeight()/N_STEPS);

关于java - Java弹跳球墙，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/21456257/