Box2dWeb机构没有发生碰撞

Question

我已将Box2dWeb实施到Node.js服务器中，除碰撞外，一切正常。当有2名球员连接时，他们的身体不会碰撞 - 只是互相通过。这是玩家身体创建代码：

//World creation
var world = new b2World(new b2Vec2(0, 0));
//Body+Fixture creation
var bodyDef = new b2BodyDef();
bodyDef.type = b2Body.b2_dynamicBody;
bodyDef.position.x = 100;
bodyDef.position.y = 100;
bodyDef.linearDamping = 5;
bodyDef.angularDamping = 1;

var fixDef = new b2FixtureDef();
fixDef.density = 0.001;
fixDef.friction = 1;
fixDef.restitution = 1;
fixDef.shape = new b2CircleShape;
fixDef.shape.SetRadius(8);

var body = world.CreateBody(bodyDef);
body.CreateFixture(fixDef);

非常感谢任何帮助！

编辑：我已添加此代码：

var listener = new Box2D.Dynamics.b2ContactListener;
listener.BeginContact = function(contact) {
    console.log(contact.GetFixtureA().GetBody().GetUserData());
}
world.SetContactListener(listener);

一旦身体发生碰撞，我得到＆＃34; null＆＃34;在控制台中。

Answer 1

好的，这很简单，就像我预期的那样。我改变了代码：

this.world.Step(deltaTime);

到

this.world.Step(deltaTime, 10, 10);