handleTouchStartDolly method
void
handleTouchStartDolly()
Implementation
void handleTouchStartDolly() {
final dx = pointers[0].pageX - pointers[1].pageX;
final dy = pointers[0].pageY - pointers[1].pageY;
final distance = math.sqrt(dx * dx + dy * dy);
dollyStart.setValues(0, distance);
}