box2d 2.2 b2Body GetGroundBody 方法消失了

Question

我尝试休耕用旧的 box2d 编写的教程<=2.1我无法理解如何替换 b2Body 的 GetGroundBody 方法到 box2d>= 2.2

var jointDef:b2MouseJointDef=new b2MouseJointDef();
jointDef.bodyA=world.GetGroundBody();   // what does it need to be now?
jointDef.bodyB=touchedBody;
jointDef.target=mouseToWorld();
jointDef.maxForce=1000*touchedBody.GetMass();
mouseJoint=world.CreateJoint(jointDef) as b2MouseJoint;

Answer 1

您可以创建自己的静态主体以充当地面主体。