LibGDX需要帮助才能在box2d中使用视口

Question

我在将视口应用到项目时遇到了问题。下面的代码试图让控制面板移动球。但是，当我尝试使用视口时，我不知道该怎么做。所以我试图从头开始遵循游戏方法。我在构造函数中添加了以下代码。

  camera = new OrthographicCamera();
  viewport = new FitViewport(1280,720,camera);
  viewport.apply();

  camera.position.set(camera.viewportWidth/2,camera.viewportHeight/2,0);

我一无所获。屏幕上没有任何内容。我尝试将相机位置设置到不同的位置，我什么也看不见。我的代码有什么问题？

public class GameScreen extends AbstractScreen {

private OrthographicCamera camera;
private Viewport viewport;
private MyInputHandler handler;

//Box2D
World world;
Box2DDebugRenderer b2dr;
Body body;
Body control;
Fixture fixture;

//Parameters for controls
private double angle;
private double ControlMagnitudeX;
private double ControlMagnitudeY;
private float fControlMagnitudeX;
private float fControlMagnitudeY;


public GameScreen(final HunterLife game) {
    super(game);
    this.camera = new OrthographicCamera();

    camera.setToOrtho(false, HunterLife.V_WIDTH/PPM, HunterLife.V_HEIGHT/PPM);

    this.world = new World(new Vector2(0f, 0f), true);

    this.b2dr = new Box2DDebugRenderer();

    handler = new MyInputHandler();

    BodyDef controlDef = new BodyDef();
    controlDef.type = BodyDef.BodyType.StaticBody;
    controlDef.position.set(HunterLife.V_WIDTH/8/PPM, HunterLife.V_HEIGHT/5/PPM);
    this.control = world.createBody(controlDef);
    CircleShape controlCircle = new CircleShape();
    controlCircle.setRadius (0.1f);
    FixtureDef controlFixture = new FixtureDef();
    controlFixture.shape = controlCircle;
    controlFixture.isSensor = true;
    control.createFixture(controlFixture);


    BodyDef bdef = new BodyDef();
    bdef.type = BodyDef.BodyType.DynamicBody;
    bdef.position.set(HunterLife.V_WIDTH/2/PPM,HunterLife.V_HEIGHT/2/PPM);
    FixtureDef fdef = new FixtureDef();
    this.body = world.createBody(bdef);
    CircleShape circle = new CircleShape();
    circle.setRadius (0.05f);
    fdef.shape = circle;
    fdef.density = 1f;
    fdef.friction = 0f;
    fdef.restitution = 1f;
    fixture = body.createFixture(fdef);

    circle.dispose();
    controlCircle.dispose();

}


@Override
public void show() {

}

@Override
public void update(float delta) {
    world.step(1 / 60f, 6, 2);
    if (Gdx.input.isTouched()) {
        if (((HunterLife.V_HEIGHT - Gdx.input.getY() * HunterLife.V_HEIGHT / Gdx.graphics.getHeight()) - control.getPosition().y * PPM) * ((HunterLife.V_HEIGHT - Gdx.input.getY() * HunterLife.V_HEIGHT / Gdx.graphics.getHeight()) - control.getPosition().y * PPM) + ((Gdx.input.getX() * HunterLife.V_WIDTH / Gdx.graphics.getWidth()) - control.getPosition().x * PPM) * ((Gdx.input.getX() * HunterLife.V_WIDTH / Gdx.graphics.getWidth()) - control.getPosition().x * PPM) <= 0.25f * 0.25f * PPM * PPM) {

            angle = Math.abs(Math.atan(((HunterLife.V_HEIGHT - Gdx.input.getY() * HunterLife.V_HEIGHT / Gdx.graphics.getHeight()) - control.getPosition().y * PPM) / ((Gdx.input.getX() * HunterLife.V_WIDTH / Gdx.graphics.getWidth()) - control.getPosition().x * PPM)));
            ControlMagnitudeX = 0.15f * Math.cos(angle);
            ControlMagnitudeY = 0.15f * Math.sin(angle);
            fControlMagnitudeX = MyInputHandler.getFloat(ControlMagnitudeX);
            fControlMagnitudeY = MyInputHandler.getFloat(ControlMagnitudeY);

            if ((HunterLife.V_HEIGHT - Gdx.input.getY() * HunterLife.V_HEIGHT / Gdx.graphics.getHeight()) >= control.getPosition().y * PPM && (Gdx.input.getX() * HunterLife.V_WIDTH / Gdx.graphics.getWidth()) >= control.getPosition().x * PPM) {
                body.setLinearVelocity(fControlMagnitudeX, fControlMagnitudeY);
            }
            if ((HunterLife.V_HEIGHT - Gdx.input.getY() * HunterLife.V_HEIGHT / Gdx.graphics.getHeight()) < control.getPosition().y * PPM && (Gdx.input.getX() * HunterLife.V_WIDTH / Gdx.graphics.getWidth()) >= control.getPosition().x * PPM) {
                body.setLinearVelocity(fControlMagnitudeX, -fControlMagnitudeY);
            }
            if ((HunterLife.V_HEIGHT - Gdx.input.getY() * HunterLife.V_HEIGHT / Gdx.graphics.getHeight()) >= control.getPosition().y * PPM && (Gdx.input.getX() * HunterLife.V_WIDTH / Gdx.graphics.getWidth()) < control.getPosition().x * PPM) {
                body.setLinearVelocity(-fControlMagnitudeX, fControlMagnitudeY);
            }
            if ((HunterLife.V_HEIGHT - Gdx.input.getY() * HunterLife.V_HEIGHT / Gdx.graphics.getHeight()) < control.getPosition().y * PPM && (Gdx.input.getX() * HunterLife.V_WIDTH / Gdx.graphics.getWidth()) < control.getPosition().x * PPM) {
                body.setLinearVelocity(-fControlMagnitudeX, -fControlMagnitudeY);
            }
        }
        else {
            body.setLinearVelocity(0, 0);
        }
    }
    else {
        body.setLinearVelocity(0, 0);
    }
    stage.act();
}



@Override
public void render(float delta) {
    super.render(delta);
    game.sb.setProjectionMatrix(camera.combined);
    game.shapeBatch.setProjectionMatrix(camera.combined);
    camera.update();
    b2dr.render(world, camera.combined);
    stage.draw();
}

@Override
public void resize(int width, int height) {
}


@Override
public void pause() {

}

@Override
public void resume() {

}

@Override
public void hide() {

}

@Override
public void dispose() {
    super.dispose();
    world.dispose();
}
}

请忽略舞台的事情。 上面的代码没有问题。添加视口内容时会出现问题。