@ccclass
export default class NewClass extends cc.Component {

    @property (cc.RigidBody)
    floor: cc.RigidBody = null // 1

    @property gravity: number = 0;

    // LIFE-CYCLE CALLBACKS:
    onLoad () {
        let physicsManager = cc.director.getPhysicsManager() // 2
        physicsManager.enabled = true
        physicsManager.gravity = cc.v2(0, this.gravity)
    }

}