首先在createScene()里
auto scene = Scene::createWithPhysics();
创建带有物理的场景
然后再OnEnter里创建边界框
auto body = PhysicsBody::createEdgeBox( visibleSize, PHYSICSBODY_MATERIAL_DEFAULT, 3);
创建一个节点承载边界
auto edgeShape = Node::create();将图形和刚刚创建的世界绑定edgeShape->setPhysicsBody( body);置图形的位置在屏幕正中间edgeShape->setPosition( visibleSize.width / 2, visibleSize.height / 2);
添加进图层addChild( edgeShape);