创建简单碰撞检测

Question

我创建了一个非常简单的程序，其中我使用绘画绘制了一个迷宫（使用fillRect方法创建迷宫的墙），我还创建了一个精灵，它可以使用keyListener移动。我想实现一个简单的碰撞检测（就像我在通勤科学的第一年一样），以防止精灵穿过迷宫的墙壁。因为迷宫是用将近400行代码绘制的，所以我不包括它。

import java.awt.*;
import java.applet.*;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;

public class IndeProj extends Applet implements KeyListener {


    //KEY LISTENER INFO FOR MY SPRITE
    public int x = 10;
    public int y = 575;
    public boolean keyUp;  
    public boolean keyDown;  
    public boolean keyLeft;  
    public boolean keyRight;


    public void paint(Graphics g) {
        //drawMaze
        drawMazeHorizontalLines(g);
        drawMazeVerticalLines(g);

        //SPRITE STUFF
        addKeyListener(this);
        this.MoveRect(g,x,y);

    }

    public void drawMazeHorizontalLines(Graphics g)
    {
        //This method draws the horizontal lines of the maze using the method `fillRect(x,y,w,h)`
    }

    public void drawMazeVerticalLines (Graphics g)
    {
        //This method draws the vertical lines of the maze using `fillRect(x,y,w,h)`
    }


    public void MoveRect(Graphics g, int x, int y) //Draws Sprite   
    {
        g.setColor(Color.green);
        g.fillRect(x,y,20,20);
        g.setColor(Color.yellow); //Sprite body
        g.fillRect(x,y,20,20);
        g.setColor(Color.green); //Sprite eyes
        g.fillRect(x,y,7,7);
        g.fillRect((x+13),y,7,7);
        g.setColor(Color.blue); //Sprite pants
        g.fillRect(x,(y+13),20,7);
        g.setColor(Color.black); //Sprite mouth
        g.fillRect((x+6),(y+9),8,2);
    }

    public void keyPressed(KeyEvent e) //Moves Sprite
    {
        if (e.getKeyCode() == KeyEvent.VK_DOWN) {
            y+=1;
            y+=0;
        } if (e.getKeyCode() == KeyEvent.VK_UP) {
            y-=1;
            y-=0;
        } if (e.getKeyCode() == KeyEvent.VK_LEFT) {
            x-=1;
            x-=0;
        } if (e.getKeyCode() == KeyEvent.VK_RIGHT) {
            x+=1;
            x+=0;
        }
        repaint();
    }
    public void keyReleased(KeyEvent e) //Stops Sprite  
    {   
         keyUp = keyDown = keyLeft = keyRight = false;
    }
}

我想使精灵在碰到墙时停止（使用x和y坐标），精灵将停止移动。

Answer 1

我的方法是使用矩形碰撞框。playerX和playerY是玩家的坐标：

while(true) {
    while(!((playerX > 50 && playerX < 100) && (playerY > 50 && playerY < 100))){
        //Put code to let they players walk here, and boundaries will be enforced.
    }
}

那将是一个矩形框，你不能进入它的边界。

Answer 2

如果小程序是双缓冲的，则可以在它们移动之前执行以下操作：

Color c = new Color(buffer.getRGB(desiredPlayerX, desiredPlayerY));
if(c.equals(<Whatever color you used for the maze walls>)){
    // Don't allow the movement of the player
}else{
    x = desiredPlayerX;
    y = desiredPlayerY;
}

不过，这种方法看起来确实有点“hacky”，我相信有更好的方法来实现它，但这是一个可能的快速解决方案。

Answer 3

这是一种简单的碰撞检测方法，地图是一个整数网格，每个整数都有它所包含的墙。如果你做错了，你会得到神奇的单向墙。

/* could use enums for this */
public static int WALL_LEFT = 1;
public static int WALL_RIGHT = 2;
public static int WALL_TOP = 4;
public static int WALL_BOTTOM = 8;


public int[][] createSimpleMap(){
    int[][] map = new int[2][2];
    map[0][0] = WALL_LEFT | WALL_RIGHT | WALL_TOP;
    map[0][1] = WALL_LEFT | WALL_RIGHT | WALL_TOP;
    map[1][0] = WALL_LEFT | WALL_BOTTOM;
    map[1][1] = WALL_RIGHT | WALL_BOTTOM;
    return map;
}

要进行碰撞检测，只需检测墙是否存在。

public boolean canMoveUp(x,y){
    return (this.map[x][y] & WALL_TOP) ==0;
}