如何用键盘控制Box2d中的刚体移动

987212385

987212385

两个刚体发出碰撞的时候有没有什么事件驱动 啊，，，，，，，，，比如说返回一个值

987212385

  //添加一个框子
        wallLayer = new LSprite();
        wallLayer.x = 400;
        wallLayer.y = 0;
        backLayer.addChild(wallLayer);
        wallLayer.addBodyPolygon(800,10,0);
        wallLayer = new LSprite();
        wallLayer.x = 0;
        wallLayer.y = 240;
        backLayer.addChild(wallLayer);
        wallLayer.addBodyPolygon(10,480,0);
        wallLayer = new LSprite();
        wallLayer.x = 400;
        wallLayer.y = 480;
        backLayer.addChild(wallLayer);
        wallLayer.addBodyPolygon(800,10,0);
        wallLayer = new LSprite();
        wallLayer.x = 800;
        wallLayer.y = 240;
        backLayer.addChild(wallLayer);
        wallLayer.addBodyPolygon(10,480,0);

        backLayer.graphics.drawRect(1,"#ffffff",[0, 0, 800, 5],true,"#000000");
        backLayer.graphics.drawRect(1,"#ffffff",[0, 475, 800, 5],true,"#000000");
        backLayer.graphics.drawRect(1,"#ffffff",[0, 0, 5, 480],true,"#000000");
        backLayer.graphics.drawRect(1,"#ffffff",[795,0, 5, 480],true,"#000000");


有什么作用

987212385

好像自由落体，是默认的吧