/** 开始拖动刚体*/ private void startDragBody(b2Body b, float x, float y) { if (b == null || b.GetType() != b2Body.b2_dynamicBody) { return; } if (_mj != null) { _world.DestroyJoint(_mj); } b2MouseJointDef jointDef = new b2MouseJointDef(); jointDef.bodyA = _world.GetGroundBody(); jointDef.bodyB = b; jointDef.target.Set(x, y); jointDef.maxForce = 1e6f; _mj = _world.CreateJoint(jointDef) as b2MouseJoint; }