Libgdx - Incorect model rotation values by Tween Engine

Question

I am trying to rotate a 3d ModelInstance with universal tween engine in libgdx. Here is my screen class :

public class WallpaperScreen implements Screen {

private PerspectiveCamera camera;
private ModelBatch modelBatch;
private Model modelBody, modelHead;
private ModelInstance bodyModelInstance, headModelInstance;
private Environment environment;
private TweenManager tweenManager;

@Override
public void show() {
    tweenManager = new TweenManager();
    Tween.registerAccessor(ModelInstance.class, new Accesor());

    camera = new PerspectiveCamera(75, Gdx.graphics.getWidth(),
            Gdx.graphics.getHeight());

    camera.position.set(-10f, 2f, 0f);
    camera.lookAt(0f, 0f, 0f);

    camera.near = 0.1f;
    camera.far = 300.0f;

    modelBatch = new ModelBatch();

    UBJsonReader jsonReader = new UBJsonReader();
    G3dModelLoader modelLoader = new G3dModelLoader(jsonReader);
    modelBody = modelLoader.loadModel(Gdx.files.getFileHandle(
            "data/IS3/IS3_body.g3db", FileType.Internal));
    modelHead = modelLoader.loadModel(Gdx.files.getFileHandle(
            "data/IS3/IS3_tur.g3db", FileType.Internal));
    bodyModelInstance = new ModelInstance(modelBody);
    headModelInstance = new ModelInstance(modelHead);

    bodyModelInstance.transform.rotate(0, 1, 0, -90);
    headModelInstance.transform.rotate(0, 1, 0, -90);

    environment = new Environment();
    environment.set(new ColorAttribute(ColorAttribute.AmbientLight, 1f, 1f,
            1f, 1.0f));

    Tween.to(bodyModelInstance, 0, 2).target(45).start(tweenManager);
    Tween.to(headModelInstance, 0, 2).target(45).start(tweenManager);
}

@Override
public void render(float delta) {
    Gdx.gl.glViewport(0, 0, Gdx.graphics.getWidth(),
            Gdx.graphics.getHeight());
    Gdx.gl.glClearColor(0, 128, 255, 0);
    Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT | GL20.GL_DEPTH_BUFFER_BIT);

    tweenManager.update(delta);

    camera.update();

    modelBatch.begin(camera);
    modelBatch.render(bodyModelInstance, environment);
    modelBatch.render(headModelInstance, environment);
    modelBatch.end();
}

and here is my TweenAccesor :

public class Accesor implements TweenAccessor<ModelInstance> {

private Quaternion quat = new Quaternion();

@Override
public int getValues(ModelInstance target, int tweenType,
        float[] returnValues) {
    quat = target.transform.getRotation(quat);
    returnValues[0] = quat.getAxisAngle(Vector3.Y);
    return 1;
}

@Override
public void setValues(ModelInstance target, int tweenType, float[] newValues) {
    target.transform.rotate(Vector3.Y, newValues[0]);
}

the problem is that the models spin very fast (they do a couple of full 360 degrees turn in those 2 seconds), i just need them to spin slowly from 0 degree on Y axis to 45 degrees in 2 seconds, what am i doint wrong in the accesor ?

Answer 1

Is a Quaternion stateless? There is only going to be one Accesor instance for all your Tweens.

Does target.transform.rotate(Vector3.Y, newValues[0]); rotate by X degrees or to degree X. You are slowly increasing to 45 each call. Are you seeing the rotating getting faster and faster? Maybe you want setToRotation instead.