onPointerDown method

void onPointerDown(dynamic event)

Implementation

void onPointerDown(event) {
  updatePointer(event);
  _intersections.length = 0;
  _raycaster.setFromCamera(_pointer, camera);
  _raycaster.intersectObject(_knobSprite!, true, _intersections);

  if (_intersections.isNotEmpty) {
    _knobSprite.position.add(dragPosition);
    dispatchEvent(Event(type: 'dragstart', object: _knobSprite));
  }
}