MouseJoint gets less and less reactive

Question

Still new to flame and forge2d - both very impressive stuff.

I just learned that you need a MouseJoint to move a (Body)Component so you dont mess with the physics in Forge2d/Box2d.

From this example - MouseJointSample I see that it does work for dragging the body - but after multiple onDragUpdate and onDragEnd I find it to get less and less reactive to the mouse move. Hope the following gif animation can visualise this.

Every time the mouse stands still, I release the mouse/touch, and re-onDragUpdate/onDragEnd.

Do you see this and if so, what to do. This happens both on ios emulator and in Chrome web browser.

It looks like the mouseJoint is never really destroyed, and I can make it react to mouse/touch away from the BodyComponent:

Note: I just git cloned flame (ba61779)

Answer 1

I think I found the bug, the code should be:

  @override
  bool onDragUpdate(int pointerId, DragUpdateInfo details) {
    final mouseJointDef = MouseJointDef()
      ..maxForce = 3000 * ball.body.mass * 10
      ..dampingRatio = 0.1
      ..frequencyHz = 5
      ..target.setFrom(ball.body.position)
      ..collideConnected = false
      ..bodyA = groundBody
      ..bodyB = ball.body;

    if (mouseJoint == null) {
      mouseJoint = MouseJoint(mouseJointDef);
      world.createJoint(mouseJoint!);
    }
    mouseJoint?.setTarget(details.eventPosition.game);
    return false;
  }

And not

  @override
  bool onDragUpdate(int pointerId, DragUpdateInfo details) {
    final mouseJointDef = MouseJointDef()
      ..maxForce = 3000 * ball.body.mass * 10
      ..dampingRatio = 0.1
      ..frequencyHz = 5
      ..target.setFrom(ball.body.position)
      ..collideConnected = false
      ..bodyA = groundBody
      ..bodyB = ball.body;

    mouseJoint ??= MouseJoint(mouseJointDef);
    world.createJoint(mouseJoint!);

    mouseJoint?.setTarget(details.eventPosition.game);
    return false;
  }