Threejs - mouse drag rotation

by black strings

HTML

<script src="https://rawgit.com/mrdoob/three.js/dev/build/three.js"></script>
<script src="https://rawgit.com/mrdoob/three.js/dev/examples/js/controls/OrbitControls.js"></script>

CSS

/* fix mouse click offset errors when doing drags */
body {
  margin: 0;
}

JavaScript

var scene, renderer, camera;
var cube;
var controls;
var raycaster = new THREE.Raycaster();
var mouse = new THREE.Vector2();
var intersects = new THREE.Vector3();
var dragging = false;
var plane = new THREE.Plane(new THREE.Vector3(0, 1, 0), 0);
var object;
var circle;
var previousPos;

window.addEventListener("mousemove", onMouseMove, false);
window.addEventListener("mousedown", onMouseDown, false);
window.addEventListener("mouseup", onMouseUp, false);

init();
lightSetup();
animate();

function init() {
  renderer = new THREE.WebGLRenderer({
    antialias: true
  });
  var width = window.innerWidth;
  var height = window.innerHeight;
  renderer.setSize(width, height);
  document.body.appendChild(renderer.domElement);

  scene = new THREE.Scene();

  var gridXZ = new THREE.GridHelper(1000, 100);
  scene.add(gridXZ);

  var axes = new THREE.AxesHelper(1000);
  scene.add(axes);

  camera = new THREE.PerspectiveCamera(45, width / height, 1, 10000);
  camera.position.y = 400;
  camera.position.z = 400;
  camera.lookAt(new THREE.Vector3(0, 0, 0));

  controls = new THREE.OrbitControls(camera, renderer.domElement);
  
  object = new THREE.Object3D();
  
  var image = new Image();
  
  var texture = new THREE.Texture(image);
  
  image.onload = () => {
  	texture.needsUpdate = true;
  }
  
  image.src =...