如何在libgdx中的特定时间创建敌人

Question

我是libgdx的新手。我正在开发一款有玩家身体的游戏，我有控制权，但我想在游戏中的特定时间制造敌人。我试过创建它，但只创建了玩家的身体，但没有创建敌人的身体。

这是我的代码

public class Player
    implements Screen, InputProcessor {
    private Body polybody;
    private Player player;
    private World world;
    private Body enemybody;
    private Sprite polysprite;
    public final float width, height;
    private Vector2 movement = new Vector2();
    private float speed = 580;

    public Player(World world, float x, float y, float width) {
        this.width = width; //IMP
        height = width * 2;
        BodyDef polygon = new BodyDef();
        polygon.type = BodyType.DynamicBody;
        polygon.position.set(x, y); //
        PolygonShape poly = new PolygonShape();
        poly.setAsBox(width / 2, height / 2); //
        //fixture defn
        FixtureDef polyfixture = new FixtureDef();
        polyfixture.shape = poly;
        polyfixture.friction = 0.8f;  //
        polyfixture.restitution = 0.1f; //
        polyfixture.density = 3; //
        //creating actual body
        polybody = world.createBody(polygon);
        polybody.createFixture(polyfixture);
        // polybody.applyAngularImpulse(52, true);
        polysprite = new Sprite(new Texture("img/car.jpg"));
        polysprite.setSize(0.5f, 1); //size of mario
        polysprite.setOrigin(polysprite.getWidth() / 2, polysprite.getHeight() / 2);
        polybody.setUserData(polysprite);
        poly.dispose();
    }

    public void update() {
        polybody.applyForceToCenter(movement, true);
    }
    public Body getBody() {
        return polybody;
    }
    @Override
    public void show() {
        // TODO Auto-generated method stub
    }
    final float step = 0.1f;
    float timeElapsed = 0f;
    @Override
    public void render(float delta) {
        timeElapsed += delta;
        while (timeElapsed > step) {
            timeElapsed -= step;
            Enemy();
        }
    }
    public void Enemy() {
        BodyDef enemy = new BodyDef();
        enemy.type = BodyType.DynamicBody;
        enemy.position.set(6, 3);
        PolygonShape enemypoly = new PolygonShape();
        enemypoly.setAsBox(2, 2);
        FixtureDef enemyfixture = new FixtureDef();
        enemyfixture.shape = enemypoly;
        enemyfixture.friction = 0.75f;
        enemyfixture.restitution = 0.1f;
        enemyfixture.density = 5;
        enemybody = world.createBody(enemy);
        enemybody.createFixture(enemyfixture);
        enemypoly.dispose();
    }
    @Override
    public void resize(int width, int height) {
        // TODO Auto-generated method stub
    }
    @Override
    public void pause() {
        // TODO Auto-generated method stub
    }
    @Override
    public void resume() {
        // TODO Auto-generated method stub
    }
    @Override
    public void hide() {
        // TODO Auto-generated method stub
    }

    @Override
    public void dispose() {
        // TODO Auto-generated method stub
    }
    @Override
    public boolean keyDown(int keycode) {
        // TODO Auto-generated method stub
        switch (keycode) {
            case Keys.W:
                movement.y = speed;
                break;
            case Keys.S:
                movement.y = -speed;
                break;
            case Keys.D:
                movement.x = speed;
                break;
            case Keys.A:
                movement.x = -speed;
        }
        return true;
    }
    @Override
    public boolean keyUp(int keycode) {
        // TODO Auto-generated method stub
        switch (keycode) {
            case Keys.W:
                movement.y = 0;
                break;
            case Keys.S:
                movement.y = 0;
                break;
            case Keys.D:
                movement.x = 0;
                break;
            case Keys.A:
                movement.x = 0;
        }
        return true;
    }
    @Override
    public boolean keyTyped(char character) {
        // TODO Auto-generated method stub
        return false;
    }
    @Override
    public boolean touchDown(int screenX, int screenY, int pointer, int button) {
        // TODO Auto-generated method stub
        movement.x = speed;
        Gdx.app.log("Example", "touch done ");
        return true;
    }
}

这是首先调用的播放器类，在此之后，在渲染方法中调用敌方方法。玩家的身体很好，但我看不到任何敌人的身体。请帮忙。提前谢谢！！

Answer 1

显然，您的Player类负责：

• 处理用于控制游戏的输入
• 敌方物体的构造
• 渲染整个世界（处理时间）并显示世界和所有对象
• 创建纹理（应该只创建一次，而不是每次创建Sprite！）

啊，你没有别的课了。

我认为你应该解决这个问题。

此外，我有点厌倦了每次创建对象后都要调用dispose()。

顺便说一句，只有当你为游戏设置了活动屏幕时，才会调用render()方法，所以

public class MyGame extends Game {
    ...
    MyScreen myScreen = new MyScreen();
    ...
    public void goToMyScreen() { 
        this.setScreen(myScreen);
    }
}

像这样的东西是render()工作所必需的。

请查看如何在Libgdx（android）中跟踪时间，了解如何处理经过的时间。

Answer 2

我建议对应用程序进行重构。Player类看起来并不是制造敌人的合适位置（你似乎每一步都会这样做）。相反，您应该在创建Player的同一位置创建Enemy，并为Enemy提供一个自己的类。

此外，您可以将调试消息写入控制台，或者使用IDE的调试器来检查代码实际在做什么。