[LayaAir 2.0]添加了MouseJoint没有效果

let ropePartTexture = Laya.loader.getRes("test/b1.png");

let ropePart : Sprite = new Sprite();

ropePart.texture = ropePartTexture;

ropePart.pos(48*vw,10*vh);

ropePart.width = 4*vw;

ropePart.height = 10*vh;



let boxCollider = new laya.physics.BoxCollider();

boxCollider.width = ropePart.width;

boxCollider.height = ropePart.height;

ropePart.addComponentIntance(boxCollider);



ropePart.addComponent(laya.physics.RigidBody);



// let revoluteJoint = new laya.physics.joint.RevoluteJoint();

// revoluteJoint.otherBody = rigidBody;

// revoluteJoint.anchor = [ropePart.width/2,0];

// ropePart.addComponentIntance(revoluteJoint);



let mouseJoint = new laya.physics.joint.MouseJoint();

mouseJoint.enabled = true;

mouseJoint.selfBody = <laya.physics.RigidBody>ropePart.getComponent(laya.physics.RigidBody);

ropePart.addComponentIntance(mouseJoint);

Laya.stage.addChild(ropePart);