1、邊界檢測(cè)

坦克的可以穿過(guò)四周的邊界，為了限制坦克的活動(dòng)范圍，需要作出如下更新：

private void stageEdge() {
    
        boolean stage_d = mytank.x > this.getWidth() - 64 && mytank.cmd.equals("dd");
        boolean stage_s = mytank.y > this.getHeight() - 64 && mytank.cmd.equals("ss");
        boolean stage_a = mytank.x < 0 && mytank.cmd.equals("aa");
        boolean stage_w = mytank.y < 0 && mytank.cmd.equals("ww");
        if (stage_d || stage_s || stage_a || stage_w) {
     //當(dāng)坦克觸碰到上下左右的邊界時(shí)，將塔克的指令改為只朝向?qū)?yīng)方向而不移動(dòng)，但不影響坦克其他方向的移動(dòng)
            mytank.cmd = mytank.cmd.substring(0, 1);
        }
    }

2、繪制墻體

類似于坦克的繪制，但是可以將墻體的坐標(biāo)類型保存至文件中，通過(guò)IO流讀取出來(lái)

import java.io.*;
import java.util.List;
import java.util.concurrent.CopyOnWriteArrayList;

public class GetWallsFromFile {
    private static final String WALLS_PATH = "staticTank/walls.txt";//墻配置文件路徑

    public List<String[]> getWall() {
        List<String[]> walls = new CopyOnWriteArrayList<>();
        try {
            InputStream in = new FileInputStream(WALLS_PATH);
            InputStreamReader rd = new InputStreamReader(in);
            BufferedReader br = new BufferedReader(rd);//讀取wall的配置文件
            String str;
            while ((str = br.readLine()) != null) {
                String[] strs = str.split(",");
                walls.add(strs);
            }
            br.close();
            rd.close();
            in.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return walls;
    }
}

本地配置文件可用逗號(hào)","將各個(gè)參數(shù)分開(kāi)，如下所示

200,200,b
300,270,b
410,300,b
510,260,w
800,230,b
700,360,b
620,430,p


注：X軸坐標(biāo),Y軸坐標(biāo),墻類型*(wall-*.png)

墻wall類只需要定義屬性，不需要具體繪制方法，統(tǒng)一在MyMap中實(shí)現(xiàn)，以下為wall類

public class Wall {//墻的屬性與配置文件相同
    private int x;//X軸坐標(biāo)
    private int y;//Y軸坐標(biāo)
    private String path;//墻圖片路徑，只需要其類型，在MyMap中通過(guò)字符串拼接形成完整路徑

    public Wall() {
    }

    public Wall(int x, int y, String path) {
        this.x = x;
        this.y = y;
        this.path = path;
    }

    public int getX() {
        return x;
    }

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

    public int getY() {
        return y;
    }

    public void setY(int y) {
        this.y = y;
    }

    public String getPath() {
        return path;
    }

    public void setPath(String path) {
        this.path = path;
    }
}

完成以上兩步驟后，在MyMap中創(chuàng)建wall類集合 List<Wall>，并調(diào)用讀取文件的方法形成墻類，然后再繪制：

private List<Wall> walls;
{
        walls = new CopyOnWriteArrayList<>();
        List<String[]> walltxt = new GetWallsFromFile().getWall();
        for (String[] w : walltxt) {
            walls.add(new Wall(Integer.parseInt(w[0]), Integer.parseInt(w[1]), w[2]));
        }
    }//在代碼塊中調(diào)用方法獲取墻的配置

public void show() {
    //遍歷集合，畫出各個(gè)墻體
        for (Wall w : walls) {
            Image img = null;
            try {
                String str=w.getPath();
                //通過(guò)字符串拼接，將墻的類型轉(zhuǎn)化為對(duì)應(yīng)的文件路徑
                img = ImageIO.read(new File("staticTank/wall-" + w.getPath() + ".png"));
            } catch (IOException e) {
                e.printStackTrace();
            }
            g.drawImage(img, w.getX(), w.getY(), 64, 64, stage);
        }
    }

3、碰撞檢測(cè)

到了此時(shí)，墻雖然畫好了，但是坦克在運(yùn)動(dòng)時(shí)可以穿墻，為了解決這個(gè)問(wèn)題，需要進(jìn)行二者之間的碰撞檢測(cè)。這里主要借用JDK中的Rectangle類進(jìn)行碰撞檢測(cè)，所以需要將坦克和墻轉(zhuǎn)成Rectangle類。

private void collision() {
        Rectangle rect_mytank = new Rectangle(mytank.x, mytank.y, 64, 64);
        for (Wall w : mymap.getWalls()) {
            Rectangle rect_wall = new Rectangle(w.getX(), w.getY(), 64, 64);
            //判斷條件為：二者模型碰撞，并且前進(jìn)方向碰到對(duì)應(yīng)邊（類似邊界檢測(cè)）
            boolean wall_d = rect_mytank.intersects(rect_wall) && mytank.x < w.getX() && mytank.cmd.equals("dd");
            boolean wall_s = rect_mytank.intersects(rect_wall) && mytank.y < w.getY() && mytank.cmd.equals("ss");
            boolean wall_a = rect_mytank.intersects(rect_wall) && mytank.x > w.getX() && mytank.cmd.equals("aa");
            boolean wall_w = rect_mytank.intersects(rect_wall) && mytank.y > w.getY() && mytank.cmd.equals("ww");
            if (wall_d || wall_s || wall_a || wall_w) {
                mytank.cmd = mytank.cmd.substring(0, 1);
            }
        }
    }

至此坦克大戰(zhàn)的第二階段算完成了。