libgdx - group transformation - libgdx

Question

I'm new in LibGDX.
I created group with actors in show method and add listener (where i calculate rotation matrix) and want to rotate all actors from group with batch.setTransformMatrix(matrixResult); but nothing happens. How can I force to rotate all actors of group?
#Override
public void show() {
camera = new PerspectiveCamera(67, Gdx.graphics.getWidth(), Gdx.graphics.getHeight());
camera.position.set(0f, 0f, - 120);
camera.lookAt(0,0,0);
camera.near = 0.1f;
camera.far = 300f;
camera.update();
stage = new Stage();
shader = new ShaderProgram(vertexShader, fragmentShader);
myBatch = new SpriteBatch();
shapeRenderer = new ShapeRenderer();
sphere = BuildSphere(5, 100);
group = new Group(){
#Override
public void draw(Batch batch, float parentAlpha) {
batch.setTransformMatrix(matrixResult);
super.draw(batch, parentAlpha);
}
};
group.setTouchable(Touchable.enabled);
group.addListener(new InputListener(){
#Override
public boolean touchDown(InputEvent event, float x, float y,
int pointer, int button) {
Gdx.app.log("MOUSE_X_BEG", Float.toString(x));
Gdx.app.log("MOUSE_Y_BEG", Float.toString(y));
begX = x;
begY = y;
return true;
}
#Override
public void touchDragged(InputEvent event, float x, float y,
int pointer) {
endX = x;
endY = y;
//isRotate = true;
float translationX = endX-begX;
float translationY = begY-endY;
float length = (float)Math.sqrt(Math.pow(translationX,2) + Math.pow(translationY,2));
Vector3 axis = new Vector3(0, 0, 0);
if(length>0){
if(begX-endX == 0){
axis.x = 1;
}else{
float angle = (float) (Math.atan(translationY/translationX) + Math.PI/2.0*(translationX <0 ? -1 : 1));
axis.z = 1;
axis.x = (float) Math.cos(angle);
axis.y = (float) Math.sin(angle);
}
}
quaternion = new Quaternion(axis, 0.02f*length);
Matrix4 rotation = new Matrix4(quaternion);
matrixResult = rotation.mul(matrixRotationOld);
matrixRotationOld = matrixResult;
}
});
//group.setBounds(0, 0, Gdx.graphics.getWidth(), Gdx.graphics.getHeight());
for (CenterCoordinate cenCoordinate : sphere.getPolygonCenterCoordinates()) {
Vector3 vector = cenCoordinate.getCartesianCenter();
Polygon polygon = new Polygon(1, cenCoordinate.getType().getCode(), cenCoordinate.getRadius(), cenCoordinate.getPsi(),
cenCoordinate.getKsi(), vector, cenCoordinate.getRotation());
group.addActor(polygon);
}
stage.addActor(group);
Gdx.input.setInputProcessor(stage);
}
Polygon extends Actor draw method :
#Override
public void draw(Batch batch, float parentAlpha) {
translation.setToTranslation(vertex.x, vertex.y, vertex.z);
matrix.mul(translation);
shader.begin();
shader.setUniformMatrix("u_worldView", matrix);
mesh.render(shader, GL20.GL_LINE_LOOP, 1, mesh.getNumVertices()-1);
shader.end();
matrix.idt();
}

Answer 1

Rotating the batch will not rotate the group. If you want to rotate everything i would suggest to rotate the camera of the Stage and set the Stages SpriteBatchs ProjectionMatrix to cam.combined. But to rotate only the Group use the rotateBy(degrees) or setRotation(degrees) method.
Rotating the SpriteBatch or the camera is actually only a change of the view, but rotating the Actor (in your case the Group) changes the logic of them.
In the draw() method you then will need to take care about this rotation and then you will have the result you want.