Ok, here is a script that can do that. Attach it on a camera that uses the orbit-camera.js script:
var CameraAutoRotate = pc.createScript('cameraAutoRotate');
CameraAutoRotate.attributes.add('speed', {
type: 'number',
default: 1,
title: 'Speed',
description: 'The rotate speed of camera.'
});
// initialize code called once per entity
CameraAutoRotate.prototype.initialize = function() {
this.orbitCamera = this.entity.script.orbitCamera;
};
// update code called every frame
CameraAutoRotate.prototype.update = function(dt) {
this.orbitCamera.yaw += this.speed * dt;
};