android libgdx用角度移动精灵

Question

当我触摸一个新的位置时，我有一个精灵。精灵移动到角度45的新点，精灵是32x32.png。你能救我吗？

我对LibGdx很陌生，我还在学习。我正在开发一个小游戏项目来学习这个漂亮的框架。  相同的图片如下：

是代码：

public class Game
        extends ApplicationAdapter {

    Vector2 vec2Position = new Vector2();
    Vector2 velocity = new Vector2();
    Vector2 vec2Movement = new Vector2();
    Vector2 vec2Touch = new Vector2();
    Vector2 dir = new Vector2();

    Vector3 vec3Temp = new Vector3();

    float speed = 100;

    OrthographicCamera camera;

    SpriteBatch batch;
    Texture texture;
    Sprite sprite;

    @Override
    public void create() {
        camera = new OrthographicCamera();
        camera.setToOrtho(false);

        batch = new SpriteBatch();

        texture = new Texture(Gdx.files.internal("32x32.png"));

        sprite = new Sprite(texture);

        Gdx.input.setInputProcessor(new InputAdapter() {
            @Override
            public boolean touchDown(int screenX,
                                     int screenY,
                                     int pointer,
                                     int button) {
                camera.unproject(vec3Temp.set(screenX,
                                              screenY,
                                              0));
                vec2Touch.set(vec3Temp.x,
                              vec3Temp.y);
                return true;
            }
        });
    }

    @Override
    public void render() {
        Gdx.gl20.glClear(GL20.GL_COLOR_BUFFER_BIT);
        if (Gdx.input.justTouched()){
        update(Gdx.graphics.getDeltaTime());
        }
        batch.begin();
        sprite.draw(batch);
        batch.end();
    }

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

    public void update(float deltaTime) {
        System.out.println(">>>>> check delta:" + deltaTime);
        vec2Position.set(sprite.getX(),
                         sprite.getY());
        dir.set(vec2Touch)
           .sub(vec2Position)
           .nor();
        velocity.set(dir)
                .scl(speed);
        vec2Movement.set(velocity)
                    .scl(deltaTime);
        if (vec2Position.dst2(vec2Touch) > vec2Movement.len2()) {
            vec2Position.add(vec2Movement);
        } else {
            vec2Position.set(vec2Touch);
        }
        //dung angle.
        float x2 = sprite.getX(); //Enemy's new X
        float y2 = sprite.getY(); //Enemy's new Y
        float angle; // We use a triangle to calculate the new trajectory
        angle = (float) Math
                                .atan2(vec2Touch.y - y2,
                                       vec2Touch.x - x2);
        angle = -90;
        System.out.println(">>>>> angle:"+angle);
        x2 += (float) Math.cos(angle) * 125
                      * Gdx.graphics.getDeltaTime();
        y2 += (float) Math.sin(angle) * 125
                      * Gdx.graphics.getDeltaTime();
//        sprite.setX(vec2Position.x);
//        sprite.setY(vec2Position.y);
        //  sprite.setPosition(vec2Position.x,vec2Position.y);
        sprite.setPosition(x2,
                           y2);
    }
}