java - 创建多个矩形 java libgdx

Question

您好，我是 libgdx 和 java 的新手，在屏幕上创建多个对象时遇到问题。当我单击 SPACE 时，我想在屏幕矩形上从 Pocisk 类中创建一个新对象，但当我单击它时，它就会下降。

游戏类

public class Gra extends ApplicationAdapter {
    SpriteBatch batch;
    private Texture Statektekstura, Pocisktekstura;
    private Statek statek;
    private Pocisk pocisk;

    @Override
    public void create() {
        zaladujdane();
        init();
    }

    private void init() {
        batch = new SpriteBatch();
        statek = new Statek(Statektekstura);
        pocisk = new Pocisk(Pocisktekstura);
    }

    private void zaladujdane() {
        //tekstura statku pomniejszana
        Pixmap pixmap2 = new Pixmap(Gdx.files.internal("statek.jpg"));
        Pixmap pixmap1 = new Pixmap(100, 100, pixmap2.getFormat());
        pixmap1.drawPixmap(pixmap2,
                0, 0, pixmap2.getWidth(), pixmap2.getHeight(),
                0, 0, pixmap1.getWidth(), pixmap1.getHeight()
        );
        Statektekstura = new Texture(pixmap1);

        //tekstura pocisk pomniejszona
        Pixmap pixmap20 = new Pixmap(Gdx.files.internal("pocisk.jpg"));
        Pixmap pixmap10 = new Pixmap(35, 35, pixmap20.getFormat());
        pixmap10.drawPixmap(pixmap20,
                0, 0, pixmap20.getWidth(), pixmap20.getHeight(),
                0, 0, pixmap10.getWidth(), pixmap10.getHeight()
        );

        Pocisktekstura = new Texture(pixmap10); 
    }

    @Override
    public void render() {
        udpdate();
        Gdx.gl.glClearColor(1, 1, 1, 1);
        Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
        batch.begin();
        statek.draw(batch);
        pocisk.draw(batch);

        batch.end();
    }

    private void udpdate() {
        przesuwanie();
        pocisk.y = pocisk.y+pocisk.pociskpredkosc*Gdx.graphics.getDeltaTime();      
    }

    private void przesuwanie() {
        if (Gdx.input.isKeyPressed(Keys.A)) {
            statek.x = statek.x - 250 * Gdx.graphics.getDeltaTime();
        }
        if (Gdx.input.isKeyPressed(Keys.D)) {
            statek.x = statek.x + 250 * Gdx.graphics.getDeltaTime();
        }
        if (Gdx.input.isKeyPressed(Keys.SPACE)) {

            pocisk = new Pocisk(Pocisktekstura);
            pocisk.strzal();    
        }       
    }

    @Override
    public void dispose() {
        //batch.dispose();  
    }
}

类 Pocisk 代码:

public class Pocisk extends Rectangle {

    private Texture texture;
    public float pociskpredkosc = 0;

    Pocisk(Texture texture) {
        this.texture = texture;
        this.height = texture.getHeight();
        this.width = texture.getWidth();    
    }

    public void draw(SpriteBatch batch) {
        batch.draw(texture, x, y);
    }

    public void strzal() {
        pociskpredkosc = pociskpredkosc + 80;
    }   
}

我认为我在 gra 类中失败，而不是在 Pocisk 类中失败，当我单击空格时，我应该更改什么才能始终创建一个新的矩形？

Answer 1

每次创建新对象并引用 pocisk 变量时，您都在处理单个 pocisk 引用。由该变量执行的 Pocisk 更新，以便每次 pocisk 从初始位置开始。对于多个 pocisk，您需要保留所有对象引用并对该引用执行更新，因此使用任何容器来存储所有引用。您可以使用 Array 来实现相同的目的。

public class MainGame extends ApplicationAdapter {
    SpriteBatch batch;
    private Texture Statektekstura,Pocisktekstura;
    private Statek statek;
    Array<Pocisk> pociskList;
    boolean oneAtOnce;

    @Override
    public void create () {
        zaladujdane();
        init();
    }

    private void init() {
        batch=new SpriteBatch();
        statek=new Statek(Statektekstura);
        pociskList=new Array<Pocisk>();
    }

    private void zaladujdane() {
        //tekstura statku pomniejszana
        Pixmap pixmap2 = new Pixmap(Gdx.files.internal("badlogic.jpg"));
        Pixmap pixmap1 = new Pixmap(100, 100, pixmap2.getFormat());
        pixmap1.drawPixmap(pixmap2,
                0, 0, pixmap2.getWidth(), pixmap2.getHeight(),
                0, 0, pixmap1.getWidth(), pixmap1.getHeight()
        );
        Statektekstura=new Texture(pixmap1);

        //tekstura pocisk pomniejszona
        Pixmap pixmap20 = new Pixmap(Gdx.files.internal("badlogic.jpg"));
        Pixmap pixmap10 = new Pixmap(35, 35, pixmap20.getFormat());
        pixmap10.drawPixmap(pixmap20,
                0, 0, pixmap20.getWidth(), pixmap20.getHeight(),
                0, 0, pixmap10.getWidth(), pixmap10.getHeight()
        );

        Pocisktekstura=new Texture(pixmap10);
    }

    @Override
    public void render () {
        udpdate();
        Gdx.gl.glClearColor(1, 1, 1, 1);
        Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
        batch.begin();
        statek.draw(batch);
        for(Pocisk pocisk:pociskList)
             pocisk.draw(batch);

        batch.end();
    }

    private void udpdate() {
        przesuwanie();
        for (Pocisk pocisk:pociskList)
        pocisk.y=pocisk.y+pocisk.pociskpredkosc*Gdx.graphics.getDeltaTime();
    }

    private void przesuwanie() {
        if(Gdx.input.isKeyPressed(Input.Keys.A))
        {
            statek.x=statek.x-250*Gdx.graphics.getDeltaTime();
        }
        if(Gdx.input.isKeyPressed(Keys.D))
        {
            statek.x=statek.x+250*Gdx.graphics.getDeltaTime();
        }
        if(Gdx.input.isKeyPressed(Input.Keys.SPACE))
        {
            Pocisk pocisk=new Pocisk(Pocisktekstura); //Called in game render method so create number of Object 
            pocisk.strzal();
            pociskList.add(pocisk);

        }
    }

    @Override
    public void dispose () {
        //batch.dispose();
    }
}

我会提醒您，您正在游戏 render 方法中创建 Pocisk 对象，因此当您按下 Keys.SPACE 时它会执行多次> 创建的对象数量。最好在InputProcessor接口(interface)的keyDown方法中创建对象。