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我创建了一个java程序来绘制2个圆圈并使用键盘移动..我需要测试碰撞......一旦两个球在一起......它会弹出消息“检测到碰撞”

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

class BallObject {
private int x;
private int y;
private int radius;

BallObject() {
    x=0;
    y=0;
    radius=0;
}

BallObject (int x,int y,int radius) {
    this.x=x;
    this.y=y;
    this.radius=radius;
}
public void setX(int x) {this.x=x;}
public void setY(int y) {this.y=y;}
public void setRadius(int r) {radius=r;}

public int getX() {return x;}
public int getY() {return y;}
public int getRadius() {return radius;}


}

class Ball extends JFrame implements KeyListener {
 BallObject ball1;
 BallObject ball2;

Ball() {
    super("COLLISION DETECTION BETWEEN TWO BALLS");

    setSize(800,600); //set screen resolution
    ball1 = new BallObject(getWidth()/2,getHeight()/2,20);
    ball2 = new BallObject(40,40,20);
    addKeyListener(this);
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setVisible(true);
}

public void paint(Graphics g) {
    Graphics2D g2d = (Graphics2D)g;

    g2d.setColor(Color.BLACK);
    g2d.fill(new Rectangle(0,0,800,600));

    //drawing ball1
    g2d.setColor(Color.RED);
    g2d.fillOval(ball1.getX(),ball1.getY(),ball1.getRadius()*2,ball1.getRadius()*2);
    //drawing ball2
    g2d.setColor(Color.GREEN);
    g2d.fillOval(ball2.getX(),ball2.getY(),ball2.getRadius()*2,ball2.getRadius()*2);
}

public static void main (String args[]) {




   new Ball();
}


public void keyPressed(KeyEvent e) {
    if(e.getKeyCode()==KeyEvent.VK_LEFT)
        ball1.setX(ball1.getX()-2);

    if(e.getKeyCode()==KeyEvent.VK_RIGHT)
        ball1.setX(ball1.getX()+2);

    if(e.getKeyCode()==KeyEvent.VK_UP)
        ball1.setY(ball1.getY()-2);

    if(e.getKeyCode()==KeyEvent.VK_DOWN)
        ball1.setY(ball1.getY()+2);


    if(e.getKeyCode()==KeyEvent.VK_A){
            ball2.setX(ball2.getX()-2);
            //System.out.println("Hello");
    }


    if(e.getKeyCode()==KeyEvent.VK_D)
        ball2.setX(ball2.getX()+2);

    if(e.getKeyCode()==KeyEvent.VK_W)
        ball2.setY(ball2.getY()-2);

    if(e.getKeyCode()==KeyEvent.VK_S)
        ball2.setY(ball2.getY()+2);


        repaint();
}


            //redraw the screen to show the updated ball location
public void keyTyped(KeyEvent e) {}
public void keyReleased(KeyEvent e) {}

}

所以现在我想测试两个圆圈之间的碰撞..

if (((ball2.getX()-ball1.getX())* (ball2.getX()-ball1.getX())) + ((ball2.getY()-ball1.getY())* (ball2.getY()-ball1.getY()))
            < ball1.getRadius() + ball2.getRadius()* ball1.getRadius() + ball2.getRadius() );

{
    System.out.println("The 2 circles are colliding!");
}
    }

但是程序无法正常工作..请帮助..

4

1 回答 1

4

1）你为什么有这个词ball2.getRadius()* ball1.getRadius()？(R1 + R2)*(R1 + R2)应该是两者距离的平方。

2）请清理代码..

int dX = ball2.getRadius()* ball1.getRadius(), dY = ball2.getY()-ball1.getY();
int R = ball1.getRadius() + ball2.getRadius();

if( (dX*dX +dY*dY) < R*R){

或将所有这些移到成员函数中。

if( ball2.distanceSquared(ball1) <R*R){

或者

if(ball2.collide(ball1)){
于 2013-02-04T07:49:50.313 回答