Unclear on how to use the new API for gesture interactions

[ninjz]

I've been able to implement something like what was mentioned in #62 where a camera is able to orbit around the scene just along the horizontal axis with SceneForm by using TransformableNode and DragRecognition to rotate a node with restricted rotation.

import com.google.ar.sceneform.math.Quaternion;
import com.google.ar.sceneform.math.Vector3;
import com.google.ar.sceneform.ux.BaseTransformableNode;
import com.google.ar.sceneform.ux.BaseTransformationController;
import com.google.ar.sceneform.ux.DragGesture;
import com.google.ar.sceneform.ux.DragGestureRecognizer;

public class DragRotationController extends BaseTransformationController<DragGesture> {

    // Rate that node rotates in degrees per degree of twisting.
    private float rotationRateDegrees = 0.5f;

    public DragRotationController(
            BaseTransformableNode transformableNode,
            DragGestureRecognizer gestureRecognizer
    ) {
        super(transformableNode, gestureRecognizer);
    }

    @Override
    protected boolean canStartTransformation(DragGesture gesture) {
        return getTransformableNode().isSelected();
    }

    @Override
    protected void onContinueTransformation(DragGesture gesture) {
        Quaternion localRotation = getTransformableNode().getLocalRotation();

        float rotationAmountX = -gesture.getDelta().x * rotationRateDegrees;
        Quaternion rotationDeltaX = Quaternion.eulerAngles(
                new Vector3(0, rotationAmountX, 0)
        );
        localRotation = Quaternion.multiply(rotationDeltaX, localRotation);

        getTransformableNode().setLocalRotation(localRotation);
    }

    @Override
    protected void onEndTransformation(DragGesture gesture) {}
}

import com.google.ar.sceneform.ux.TransformableNode;
import com.google.ar.sceneform.ux.TransformationSystem;

public class DragTransformableNode extends TransformableNode {
    private final DragRotationController dragRotationController;

    public DragTransformableNode(TransformationSystem transformationSystem) {
    public DragTransformableNode() {
        super(transformationSystem);

        dragRotationController = new DragRotationController(
                this,
                transformationSystem.getDragRecognizer()
        );
        addTransformationController(dragRotationController);

        getTranslationController().setEnabled(false);
        getScaleController().setEnabled(false);
        getRotationController().setEnabled(false);
    }

    /** Returns the controller that rotates this node using a drag gesture. */
    public DragRotationController getDragRotationController() { return dragRotationController; }
}

And then using DraggableTransformableNode to manipulate the camera in the scene:

DragTransformableNode cameraOrbit;
Camera camera;

TransformationSystem transformationSystem = new TransformationSystem(
        this.getResources().getDisplayMetrics(),
        new FootprintSelectionVisualizer()
);

camera = sceneView.camera;
// Rotation will be set on cameraOrbit with the camera being a child offset from the origin
cameraOrbit = new DragTransformableNode(transformationSystem);
sceneView.addChild(cameraOrbit);
sceneView.removeChild(camera);
cameraOrbit.addChild(camera);

I'm having troubles doing this with SceneView and it's new api to handle gestures. I'm really lost as there isn't any documentation around how this works. I'd really appreciate any help on how I can achieve this behavior with SceneView.

CC: @ThomasGorisse and @StevenMOG as I know you guys have worked hard on bringing the gesture functionality to this project

[ThomasGorisse]

The gestures in case of SceneView 3D are totally delegated to the Filament CameraGesture handler. You might find some answers directly within the Filament repo but it's not so much configurable from what I know.
You might also have a look at how gestures are handled with an AR usage to apply it to your orbit camera.