private Overlay objMeshTest(int appWidth, int appHeight) {
    ObjLoader objLoader = new ObjLoader();
    objLoader.loadObj(Res.openAssets("teaport.obj"));

    VertexBufferObject vertexData =
        new VertexBufferObject(objLoader.getVertexNum(), objLoader.getAttributes());
    vertexData.setVertices(objLoader.getVertexData());

    Mesh objMesh = new Mesh(vertexData);

    objMesh.setPos(0.85f * appWidth, appHeight / 2, 0);

    objMesh.addGlStatusController(new CullFaceController(BothSide));

    Texture texture = new Texture(R.drawable.mask1);
    texture.setParams(Texture.Params.LINEAR_REPEAT);
    objMesh.setTexture(texture);

    TranslateAnimation translateAnimation = new TranslateAnimation(1000, -200, -50);

    ScaleAnimation scaleAnimation = new ScaleAnimation(1000, 2, 2);

    RotateAnimation rotateAnimation = new RotateAnimation(1000, 0, 180);
    rotateAnimation.setRotateVector(1, 1, 1);

    AnimationGroup group = new AnimationGroup();
    group.add(translateAnimation);
    group.add(scaleAnimation);

    objMesh.startAnimation(group);

    return objMesh;
  }
  private TestParticleSystem particleTest(int appWidth, int appHeight) {

    TestParticleSystem testParticleSystem =
        new TestParticleSystem(50, new Texture(R.drawable.spark));

    testParticleSystem.addGlStatusController(new BlendController(GL_ONE, GL_ONE));

    testParticleSystem.setPos(appWidth / 2, appHeight / 2, -100);

    RotateAnimation rotateAnimation = new RotateAnimation(10000, 0, 360);
    rotateAnimation.setRotateVector(1, 1, 1);
    rotateAnimation.setLoop(true);
    rotateAnimation.setInterpolator(new LinearInterpolator());
    testParticleSystem.startAnimation(rotateAnimation);
    return testParticleSystem;
  }
  private void buttonTest() {
    final ButtonOverlay btn = new ButtonOverlay(R.drawable.image2, R.drawable.mask2);

    // btn.setPos(0, btn.getHeight() + 50);

    RotateAnimation rotate = new RotateAnimation(2000, 0, 360);
    rotate.setRotateVector(1, 0, 0);
    rotate.setLoop(true);
    btn.startAnimation(rotate);
    btn.addGlStatusController(new CullFaceController(BothSide));

    OverlayParent overlayParent = new OverlayParent();

    overlayParent.addChild(btn);

    overlayParent.setPos(btn.getWidth() / 2, btn.getHeight());

    addChild(overlayParent);
  }