Java 碰撞检测

Question

我正在尝试使用 intersects 检测两个形状之间的碰撞，但是检测不起作用。

打印出 Circle 对象显示 x 和 y 位置设置为 0。我怀疑位置 getter 和 setter 方法可能没有正常工作，但是，打印出此信息显示非零值。

为什么检测不起作用？

谢谢。

编辑：下面的代码现在可以工作了。有关问题/解决方案的详细信息，请参阅评论。

主要Class

import java.awt.Graphics;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class Main extends JPanel {

    public static List<Circle> circleList = new ArrayList<>();
    private static Random random = new Random();    

    public Main() {
        for (int i = 0; i < 2; i++) {
            circleList.add(new Circle(random.nextInt(500), random.nextInt(500)));
        }       
    }

    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);   
        for (Circle CircleShape : circleList) {
            CircleShape.collision();
            CircleShape.drawCircle(g);
        }
    }

    public static void main(String[] args) {
        JFrame frame = new JFrame();
        frame.setSize(500, 500);
        frame.setResizable(true);
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        frame.add(new Main());
    }

}

圆形Class

import java.awt.Graphics;

public class Circle extends Shape {

    public Circle(int x, int y) {
        super(x, y); 
        super.setSize(200, 200);
    }

    public void drawCircle(Graphics g) {
        g.setColor(colour);
        g.fillOval(x, y, 200, 200);
    }

    public void collision() {   
        for (Circle CircleShape : Main.circleList) {
            System.out.println(CircleShape);
            System.out.println(CircleShape.getxPos());

            if (this.intersects(CircleShape)) {
                System.out.println("collision detected");
             } else {
                System.out.println("no collision detected");
            }

         }  
    }

}

形状Class

import java.awt.Color;
import java.awt.Rectangle;

public class Shape extends Rectangle {

    //int x, y;
    Color colour;

    public Shape(int x, int y) {
        //this.setxPos(x);
        //this.setyPos(y);
        this.setPos(x, y);
    }
/*
    public int getxPos() {
        return this.x;
    }

    public void setxPos(int x) {
        this.x = x;
    }

    public int getyPos() {
        return this.y;
    }

    public void setyPos(int y) {
        this.y = y;
    }
*/

    public void setPos(int x, int y) {
        super.setLocation(x, y);
    }

    public Point getPos() {
        return new Point(x, y);
    }

}

Answer 1

intersects 方法需要正确设置 x、y、宽度和高度属性，因为它们用于检测对象是否与另一个对象发生碰撞。

因此，在您的 setter 方法中，您需要调用 super.setLocation(newX, newY)，并且您还应该提供有效的宽度和高度。

所以，应该是：

public void setxPos(int x) {
    this.x = x;
    super.setLocation(x, y);
}

public void setyPos(int y) {
    this.y = y;
    super.setLocation(x, y);
}

和

public Circle(int x, int y) {
    super(x, y); 
    super.setSize(200, 200);
}

或者，您可以只使用 class Rectangle:

中已经提供的方法

public Circle(int x, int y, int width, int height) {
    super(x, y, width, height);
}

并且还使用 setLocation 代替 setxPos 和 setyPos。

完整的代码会变成这样：

Shape class

import java.awt.Color;
import java.awt.Rectangle;

public class Shape extends Rectangle {

    Color colour;

    public Shape(int x, int y, int width, int height) {
        // provided by the Rectangle class. Needed for proper collision detection
        super(x, y, width, height);
    }
}

Circle class:

import java.awt.Graphics;

public class Circle extends Shape {

    public Circle(int x, int y, int width, int height) {
        super(x, y, width, height);
    }

    public void drawCircle(Graphics g) {
        g.setColor(super.colour);
        // instead of writing values here, we get them from width and height fields
        g.fillOval(x, y, (int) getWidth(), (int) getHeight());
    }

    public void collision() {
        for (Circle CircleShape : Main.circleList) {
            System.out.println(CircleShape);
            System.out.println(CircleShape.getLocation().x);

            if (this.intersects(CircleShape)) {
                System.out.println("collision detected");
            } else {
                System.out.println("no collision detected");
            }

        }
    }
}

Main class:

import java.awt.Graphics;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;

import javax.swing.JFrame;
import javax.swing.JPanel;

public class Main extends JPanel {

    public static List<Circle> circleList = new ArrayList<>();
    private static Random random = new Random();

    public Main() {
        for (int i = 0; i < 2; i++) {
            // width and height are specified here instead of inside the Circle.drawCircle method.
            circleList.add(new Circle(random.nextInt(500), random.nextInt(500), 200, 200));
        }
    }

    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        for (Circle CircleShape : circleList) {
            CircleShape.collision();
            CircleShape.drawCircle(g);
        }
    }

    public static void main(String[] args) {
        JFrame frame = new JFrame();
        frame.setSize(500, 500);
        frame.setResizable(true);
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        frame.add(new Main());
    }

}

Java 碰撞检测

Java Collision Detection

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