Threejs OrbitControl源码解析

import {Vector3} from 'three';
import {Vector2} from 'three';
import {MOUSE} from 'three';
import {Quaternion} from 'three';
import {Spherical} from 'three';
import {PerspectiveCamera} from 'three';
import {OrthographicCamera} from 'three';
import {EventDispatcher} from 'three';

import {FOV} from './CameraUtils';
import {zoomRange} from '../utils/zoomUtils';

/**
 * 实现手势控制：
 * 移动端：
 * 单指移动->平移
 * 双指转动->绕y轴旋转
 * 双指pinch->缩放
 * 双指上下滑动->绕x轴旋转(2/3D切换)
 * pc端：
 * 鼠标左键移动->平移
 * 鼠标滚轮->缩放
 * 鼠标右键移动->旋转
 * @type {[type]}
 */
const DEG2RAD = Math.PI / 180;
const INTOUCHDEVICE = 'ontouchstart' in document;
// const zoomRange = [2.3886571, 1.1943286, 0.5971643, 0.2985821, 0.1492911, 0.0746455, 0.0373227];

export let OrbitControls = function ( object, domElement ) {

  this.object = object; // Object代表camera

  this.domElement = ( domElement !== undefined ) ? domElement : document;

  // Set to false to disable this control
  this.enabled = true;

  // "target" sets the location of focus, where the object orbits around
  this.target = new Vector3();

  // How far you can dolly in and out ( PerspectiveCamera only )
  // 我理解是相机距离target的距离
  this.minDistance = 0;
  this.maxDistance = Infinity;

  // How far you can zoom in and out ( OrthographicCamera only )
  this.minZoom = 0;
  this.maxZoom = Infinity;

  // How far you can orbit vertically, upper and lower limits.
  // Range is 0 to Math.PI radians.
  // 我理解是在一个包围y轴的平面内能旋转的角度（与y轴平行线的夹角）；
  // 可以理解为绕垂直y轴和相机的target->position向量形成的平面的向量来转动（四元数）
  this.minPolarAngle = 0; // radians
  this.maxPolarAngle = Math.PI; // radians

  // How far you can orbit horizontally, upper and lower limits.
  // If set, must be a sub-interval of the interval [ - Math.PI, Math.PI ].
  // 在一个包围x轴的平面内能够旋转的角度（与x轴平行线的夹角）；可以理解为绕y轴的旋转
  this.minAzimuthAngle = - Infinity; // radians
  this.maxAzimuthAngle = Infinity; // radians

  // Set to true to enable damping (inertia)
  // If damping is enabled, you must call controls.update() in your animation loop
  this.enableDamping = false;// 阻尼
  this.dampingFactor = 0.25;

  // This option actually enables dollying in and out; left as "zoom" for backwards compatibility.
  // Set to false to disable zooming
  this.enableZoom = true;// 缩放控制（透视相机下dolly距离或正射投影下的zoom）
  this.zoomSpeed = 1.0;
  // 这个zoomScale是指的地图数据的级别
  this.zoomScale = zoomRange[zoomRange.length - 1];// 设置zoom级别1-6

  // Set to false to disable rotating
  this.enableRotate = true;
  this.rotateSpeed = 1.0;

  // Set to false to disable panning
  this.enablePan = true;
  this.keyPanSpeed = 7.0; // pixels moved per arrow key push

  // Set to true to automatically rotate around the target
  // If auto-rotate is enabled, you must call controls.update() in your animation loop
  this.autoRotate = false;
  this.autoRotateSpeed = 2.0; // 30 seconds per round when fps is 60

  // Set to false to disable use of the keys
  this.enableKeys = true;

  // The four arrow keys
  this.keys = { LEFT: 37, UP: 38, RIGHT: 39, BOTTOM: 40 };

  // Mouse buttons
  this.mouseButtons = { ORBIT: MOUSE.RIGHT, ZOOM: MOUSE.MIDDLE, PAN: MOUSE.LEFT };

  // for reset
  this.target0 = this.target.clone();
  this.position0 = this.object.position.clone();
  this.zoom0 = this.object.zoom;

  //
  // public methods
  //

  this.getPolarAngle = function () {

    return spherical.phi;

  };

  this.getAzimuthalAngle = function () {

    return spherical.theta;

  };
  // 保存当前control的target、position和相机的zoom
  this.saveState = function () {

    scope.target0.copy( scope.target );
    scope.position0.copy( scope.object.position );
    scope.zoom0 = scope.object.zoom;

  };

  // 恢复上次状态
  this.reset = function () {

    scope.target.copy( scope.target0 );
    scope.object.position.copy( scope.position0 );
    scope.object.zoom = scope.zoom0;

    scope.object.updateProjectionMatrix();
    scope.dispatchEvent( changeEvent );

    scope.update();

    state = STATE.NONE;

  };

  // this method is exposed, but perhaps it would be better if we can make it private...
  this.update = function () {

    var offset = new Vector3();

    // so camera.up is the orbit axis
    // 根据相机的up轴指向和y轴来求出一个表示绕垂直这两向量形成的平面的向量的转动夹角
    // 这个四元数表示初始时相机up与y轴的夹角
    var quat = new Quaternion().setFromUnitVectors( object.up, new Vector3( 0, 1, 0 ) );
    var quatInverse = quat.clone().inverse();// 求共轭四元数

    var lastPosition = new Vector3();
    var lastQuaternion = new Quaternion();

    /**
     * [update description]
     * @param  {[type]} updateZoomScale [zoomScale相同时仍然触发zoom事件]
     * @param  {[type]} noUpdateZoom    [是否触发zoom事件]
     * @return {[type]}                 [description]
     */
    return function update(updateZoomScale, noUpdateZoom) {

      var position = scope.object.position; // 这个时候position跟target应该都还未变化

      offset.copy( position ).sub( scope.target );// 形成一个从target->position的向量

      // rotate offset to "y-axis-is-up" space
      // 相机可以做各种旋转up也会有各种变化，但我们希望将y轴作为相机的up轴，这样方便计算
      offset.applyQuaternion( quat );// 用一个四元素来旋转向量, v‘ = qvq-1

      // angle from z-axis around y-axis
      spherical.setFromVector3( offset );// 将相机位置转化成球面坐标

      if ( scope.autoRotate && state === STATE.NONE ) {

        rotateLeft( getAutoRotationAngle() );

      }

      // 在我看来每次手势事件转动物体实际都是相当于在转动一个球，
      // 以屏幕中心为原点转动轴就是世界坐标系的三个轴，
      // 而我们观察到的物体就是将相机帮到球上转动后的结果，
      // 所以我们先把相机的up轴设置为与y轴重合，
      // 这样相机就相当于在一个标准单位球下来转动、缩放
      // 最后再将相机放回原先的up轴所在空间
      // 这样的好处就是通过改变相机来改变视域中的所有物体，而不是要改变物体的模型矩阵
      spherical.theta += sphericalDelta.theta;
      // console.log('theta: ' + spherical.theta * 180 / Math.PI, 'phi: ' + spherical.phi * 180 / Math.PI);
      // restrict theta to be between desired limits
      spherical.theta = Math.max( scope.minAzimuthAngle, Math.min( scope.maxAzimuthAngle, spherical.theta ) );

      // if (scope.object instanceof PerspectiveCamera) {
        // console.log('spherical.phi:  ', spherical.phi, 'sphericalDelta.phi:   ', sphericalDelta.phi);
        spherical.phi += sphericalDelta.phi;
        // restrict phi to be between desired limits
        spherical.phi = Math.max( scope.minPolarAngle, Math.min( scope.maxPolarAngle, spherical.phi ) );
      // }

      spherical.makeSafe();


      spherical.radius *= scale; // 缩放，dollyIn或dollyOut
      // console.log('scale: ' + scale);
      // restrict radius to be between desired limits
      spherical.radius = Math.max( scope.minDistance, Math.min( scope.maxDistance, spherical.radius ) );
      // console.log('spherical.radius: ' + spherical.radius, scope.minDistance, scope.maxDistance);
      // move target to panned location
      scope.target.add( panOffset ); // 利用向量加法将观察点向平移方向移动
      // console.log('target: ', scope.target);
      offset.setFromSpherical( spherical ); // 利用y轴为up轴的球面坐标坐标系来设置target-position向量

      // rotate offset back to "camera-up-vector-is-up" space
      offset.applyQuaternion( quatInverse ); // 然后将相机的target-position旋转到以相机真正up轴为相机正上方的空间中
      // 利用向量加法将新观察点的向量与target-position相加，得到相机新的位置
      // 这样就通过移动相机来实现移动物体；而不是要修改每个物体的模型矩阵
      position.copy( scope.target ).add( offset );

      scope.object.lookAt( scope.target );

      // if (sphericalDelta.theta !== 0 || sphericalDelta.phi !== 0) {
        scope.dispatchEvent({
          type: 'rotation-change',
          sphericalDelta: sphericalDelta,
          spherical: spherical
        });
      // }
      if ( scope.enableDamping === true ) {

        sphericalDelta.theta *= ( 1 - scope.dampingFactor );
        sphericalDelta.phi *= ( 1 - scope.dampingFactor );

      } else {

        sphericalDelta.set( 0, 0, 0 );

      }

      if (!noUpdateZoom) {
        if (scale !== 1 || updateZoomScale) {
          var zoomLevel = getZoomRange(spherical.radius);
          if (scope.zoomScale !== zoomLevel || updateZoomScale) {
            scope.dispatchEvent({
              type: 'zoom-change',
              zoom: zoomLevel
            });
            scope.zoomScale = zoomLevel;
          }

          scope.dispatchEvent({
            type: 'scale-change',
            scale: scale
          });

          // console.log('zoomLevel: ' + zoomLevel);
        }
      }


      // 重置变量
      scale = 1;
      panOffset.set( 0, 0, 0 );
      // update condition is:
      // min(camera displacement, camera rotation in radians)^2 > EPS
      // using small-angle approximation cos(x/2) = 1 - x^2 / 8
      // 满足更新条件时才会记录
      var ds = lastPosition.distanceToSquared( scope.object.position );
      if ( zoomChanged ||
        ds > EPS ||
        8 * ( 1 - lastQuaternion.dot( scope.object.quaternion ) ) > EPS ) {

        scope.dispatchEvent( changeEvent );

        lastPosition.copy( scope.object.position );
        lastQuaternion.copy( scope.object.quaternion );
        zoomChanged = false;

        return true;

      }
      return false;

    };

  }();

  // this.getPixelMeterRatio = function(target) {
  //   target = target ? target : scope.target;
  //   var element = scope.domElement === document ?
  //     scope.domElement.body : scope.domElement;
  //   var distance = scope.object.position.distanceTo(target);
  //   var h = scope.object instanceof PerspectiveCamera ?
  //     (Math.tan(scope.object.fov / 2 * DEG2RAD) * distance) * 2 :
  //     (scope.object.top - scope.object.bottom) / scope.object.zoom;
  //   var meterPerPixel = h / element.clientHeight;

  //   return meterPerPixel;
  // }

  this.goTop = function() {
    sphericalDelta.phi = -spherical.phi;
  }

  this.getScaleByDistance = function(distance) {
    return distance / spherical.radius;
  }

  this.getScaleByZoom = function(zoom) {
    if (scope.object instanceof OrthographicCamera) {
      return 1;
    }
    var element = scope.domElement === document ?
      scope.domElement.body : scope.domElement;
    var ratio = zoomRange[zoom - 1];
    var h = ratio * element.clientHeight;
    var distance = h / 2 / Math.tan(scope.object.fov / 2 * DEG2RAD);
    var eyeDis = scope.object.position.distanceTo(scope.target);

    return distance / eyeDis;
  }

  this.setScale = function(s, noUpdateZoom, updateZoomScale) {
    scale = s;
    scope.update(updateZoomScale, noUpdateZoom);
  }

  this.unprojectPan = function(deltaVector, moveDown, target) {
    // var getProjectLength()
    var element = scope.domElement === document ? scope.domElement.body : scope.domElement;

    var cxv = new Vector3(0, 0, 0).setFromMatrixColumn(scope.object.matrix, 0);// 相机x轴
    var cyv = new Vector3(0, 0, 0).setFromMatrixColumn(scope.object.matrix, 1);// 相机y轴
    // 相机轴都是单位向量
    var pxl = deltaVector.dot(cxv)/* / cxv.length()*/; // 向量在相机x轴的投影
    var pyl = deltaVector.dot(cyv)/* / cyv.length()*/; // 向量在相机y轴的投影

    // offset=dx * vector(cx) + dy * vector(cy.project(xoz).normalize)
    // offset由相机x轴方向向量+相机y轴向量在xoz平面的投影组成
    var dv = deltaVector.clone();
    dv.y = 0; // 目前算法不会改变相机target的y分量
    dv.sub(cxv.multiplyScalar(pxl));
    pyl = dv.length();

    if ( scope.object instanceof PerspectiveCamera ) {
      // perspective

      var position = scope.object.position;
      var offset = new Vector3(0, 0, 0);
      offset.copy(position).sub(target || scope.target);
      var distance = offset.length();
      distance *= Math.tan(scope.object.fov / 2 * Math.PI / 180);
      // console.log('unprojectPan distance: ',distance);

      // var xd = 2 * distance * deltaX / element.clientHeight;
      // var yd = 2 * distance * deltaY / element.clientHeight;
      // panLeft( xd, scope.object.matrix );
      // panUp( yd, scope.object.matrix );

      var deltaX = pxl * element.clientHeight / (2 * distance);
      var deltaY = pyl * element.clientHeight / (2 * distance) * (moveDown ? -1 : 1);

      return [deltaX, deltaY];
    } else if ( scope.object instanceof OrthographicCamera ) {

      // orthographic
      // panLeft( deltaX * ( scope.object.right - scope.object.left ) / scope.object.zoom / element.clientWidth, scope.object.matrix );
      // panUp( deltaY * ( scope.object.top - scope.object.bottom ) / scope.object.zoom / element.clientHeight, scope.object.matrix );
      var deltaX = pxl * element.clientWidth * scope.object.zoom / (scope.object.right - scope.object.left);
      var deltaY = pyl * element.clientHeight * scope.object.zoom / (scope.object.top - scope.object.bottom) * (moveDown ? -1 : 1);

      return [deltaX, deltaY];
    } else {

      // camera neither orthographic nor perspective
      console.warn( 'WARNING: OrbitControls.js encountered an unknown camera type - pan disabled.' );

    }
  }


  this.projectPan = function(deltaX, deltaY) {
    var element = scope.domElement === document ? scope.domElement.body : scope.domElement;
    var deltaVector = new Vector3(0, 0, 0);
    if ( scope.object instanceof PerspectiveCamera ) {

      var position = scope.object.position;
      var offset = new Vector3(0, 0, 0);
      offset.copy(position).sub(scope.target);
      var distance = offset.length();
      distance *= Math.tan(scope.object.fov / 2 * Math.PI / 180);

      var xd = 2 * distance * deltaX / element.clientHeight;
      var yd = 2 * distance * deltaY / element.clientHeight;
      panLeft( xd, scope.object.matrix );
      panUp( yd, scope.object.matrix );

      deltaVector.set(panOffset.x, panOffset.y, panOffset.z);
      panOffset.set(0, 0, 0);
      return deltaVector;

    } else if ( scope.object instanceof OrthographicCamera ) {

      // orthographic
      panLeft( deltaX * ( scope.object.right - scope.object.left ) / scope.object.zoom / element.clientWidth, scope.object.matrix );
      panUp( deltaY * ( scope.object.top - scope.object.bottom ) / scope.object.zoom / element.clientHeight, scope.object.matrix );

      deltaVector.set(panOffset.x, panOffset.y, panOffset.z);
      panOffset.set(0, 0, 0);
      return deltaVector;
    } else {

      // camera neither orthographic nor perspective
      console.warn( 'WARNING: OrbitControls.js encountered an unknown camera type - pan disabled.' );
    }
  }

  this.dispose = function () {

    scope.domElement.removeEventListener( 'contextmenu', onContextMenu, false );
    scope.domElement.removeEventListener( 'mousedown', onMouseDown, false );
    scope.domElement.removeEventListener( 'wheel', onMouseWheel, false );

    scope.domElement.removeEventListener( 'touchstart', onTouchStart, false );
    scope.domElement.removeEventListener( 'touchend', onTouchEnd, false );
    scope.domElement.removeEventListener( 'touchmove', onTouchMove, false );

    document.removeEventListener( 'mousemove', onMouseMove, false );
    document.removeEventListener( 'mouseup', onMouseUp, false );

    window.removeEventListener( 'keydown', onKeyDown, false );

    //scope.dispatchEvent( { type: 'dispose' } ); // should this be added here?

  };

  this.getPixelMeterRatio = function(target) {
    target = target ? target : scope.target;
    var distance = scope.object.position.distanceTo(target);
    return getPixelMeterRatioByDistance(distance);
  }

  function getPixelMeterRatioByDistance(distance) {
    var element = scope.domElement === document ?
      scope.domElement.body : scope.domElement;
    // var distance = scope.object.position.distanceTo(target);
    var h = scope.object instanceof PerspectiveCamera ?
      (Math.tan(scope.object.fov / 2 * DEG2RAD) * distance) * 2 :
      (scope.object.top - scope.object.bottom) / scope.object.zoom;
    var meterPerPixel = h / element.clientHeight;

    return meterPerPixel;
  }

  function getDistanceByPixelMeterRatio(ratio) {
    var element = scope.domElement === document ?
      scope.domElement.body : scope.domElement;
    let cameraScreenHeight = ratio * element.clientHeight;
    let distance = cameraScreenHeight / 2 / Math.tan((scope.object.fov || FOV) / 2 * DEG2RAD);

    return distance;
  }

  function getZoomRange(ds) {
    // return 5;
    let meterPerPixel = scope.getPixelMeterRatio();
    // var maxIdx = zoomRange.length - 1;
    // if (meterPerPixel <= zoomRange[maxIdx]) {
    //   return maxIdx + 1;
    // } else if(meterPerPixel >= zoomRange[0]) {
    //   return 0 + 1;
    // }
    // for (var i = 1, len = zoomRange.length; i < len; i++) {
    //   if (meterPerPixel <= zoomRange[i] && meterPerPixel > zoomRange[i + 1]) {
    //     return i + 1;
    //   }
    // }
    return getZoomRangeByRatio(meterPerPixel);
  }

  function getZoomRangeByRatio(meterPerPixel) {
    // let meterPerPixel = scope.getPixelMeterRatio();
    var maxIdx = zoomRange.length - 1;
    if (meterPerPixel <= zoomRange[maxIdx]) {
      return maxIdx + 1;
    } else if(meterPerPixel >= zoomRange[0]) {
      return 0 + 1;
    }
    for (var i = 0, len = zoomRange.length; i < len; i++) {
      if (meterPerPixel <= zoomRange[i] && meterPerPixel > zoomRange[i + 1]) {
        return i + 1;
      }
    }
  }

  //
  // internals
  //

  var scope = this;


  var changeEvent = { type: 'change' };
  var startEvent = { type: 'start' };
  var endEvent = { type: 'end' };

  var STATE = { NONE: - 1, ROTATE: 0, DOLLY: 1, PAN: 2, TOUCH_ROTATE: 3,
    TOUCH_DOLLY: 4, TOUCH_PAN: 5, TOUCH_ROTATE_THETA: 6, TOUCH_ROTATE_PHI: 7 };

  var state = STATE.NONE;

  var EPS = 0.000001;

  // current position in spherical coordinates
  // 当前的球面坐标系；所有在屏幕的旋转最终都映射为球的转动；
  // 也就是说你在2d屏幕的转动实际上相当于在转一个球
  var spherical = new Spherical();
  var sphericalDelta = new Spherical();

  var scale = 1;
  var panOffset = new Vector3();
  var zoomChanged = false;

  // 记录touchstart开始的时间，主要用于处理双指事件时判断是旋转还是缩放
  var touchStartTime = null;

  var rotateStart = new Vector2();
  var rotateEnd = new Vector2();
  var rotateDelta = new Vector2();

  var touchThetaRotateStart = new Vector2();
  var touchThetaRotateEnd = new Vector2();
  var touchPhiFingerStart1 = new Vector2();
  var touchPhiFingerEnd1 = new Vector2();
  var touchPhiFingerStart2 = new Vector2();
  var touchPhiFingerEnd2 = new Vector2();

  var panStart = new Vector2();
  var panEnd = new Vector2();
  var panDelta = new Vector2();

  var dollyStart = new Vector2();
  var dollyEnd = new Vector2();
  var dollyDelta = new Vector2();

  function getAutoRotationAngle() {

    return 2 * Math.PI / 60 / 60 * scope.autoRotateSpeed;

  }

  function getZoomScale() {

    return Math.pow( 0.95, scope.zoomSpeed );

  }

  function rotateLeft( angle ) {// 绕y轴向左转
    // console.log('rotateLeft: ' + sphericalDelta.theta * 180 / Math.PI + ' ' + angle * 180 / Math.PI);
    sphericalDelta.theta -= angle;
  }

  function rotateUp( angle ) {// 极坐标向上转动
    // console.log('rotateUp: ' + sphericalDelta.phi * 180 / Math.PI + ' ' + angle * 180 / Math.PI);
    sphericalDelta.phi -= angle;
  }
  // x轴控制世界的左右、y轴控制世界的上下，z轴控制物体离屏幕的远近
  var panLeft = function () {

    var v = new Vector3();

    return function panLeft( distance, objectMatrix ) {// panLeft只求出沿着x轴向左平移的距离

      v.setFromMatrixColumn( objectMatrix, 0 ); // get X column of objectMatrix
      v.multiplyScalar( - distance );

      panOffset.add( v );

    };

  }();

  var panUp = function () {

    var v = new Vector3();

    return function panUp( distance, objectMatrix ) {// panUp求出沿着y轴向上平移的距离

      v.setFromMatrixColumn( objectMatrix, 1 ); // get Y column of objectMatrix

      var h = v.dot(new Vector3(0, 1, 0));
      v.sub(new Vector3(0, h, 0));
      v.normalize();
      v.multiplyScalar( distance );

      panOffset.add( v );

    };

  }();

  // deltaX and deltaY are in pixels; right and down are positive
  var pan = function () {

    var offset = new Vector3();

    return function pan( deltaX, deltaY ) {

      var element = scope.domElement === document ? scope.domElement.body : scope.domElement;

      if ( scope.object instanceof PerspectiveCamera ) {

        // perspective
        var position = scope.object.position;
        offset.copy( position ).sub( scope.target );
        var targetDistance = offset.length();

        // half of the fov is center to top of screen
        targetDistance *= Math.tan( ( scope.object.fov / 2 ) * Math.PI / 180.0 );// 计算出透视屏幕的高度
// console.log('pan targetDistance: ',targetDistance);
        // we actually don't use screenWidth, since perspective camera is fixed to screen height
        // 不使用屏幕宽度，因为透视相机的屏幕高度是固定的
        // 平移的要点是沿着相机投影屏幕的的x轴、y轴移动，也就是沿着相机的right轴和up轴移动
        panLeft( 2 * deltaX * targetDistance / element.clientHeight, scope.object.matrix );
        panUp( 2 * deltaY * targetDistance / element.clientHeight, scope.object.matrix );

      } else if ( scope.object instanceof OrthographicCamera ) {

        // orthographic
        panLeft( deltaX * ( scope.object.right - scope.object.left ) / scope.object.zoom / element.clientWidth, scope.object.matrix );
        panUp( deltaY * ( scope.object.top - scope.object.bottom ) / scope.object.zoom / element.clientHeight, scope.object.matrix );

      } else {

        // camera neither orthographic nor perspective
        console.warn( 'WARNING: OrbitControls.js encountered an unknown camera type - pan disabled.' );
        scope.enablePan = false;

      }

    };

  }();

  function dollyIn( dollyScale ) {

    // if ( scope.object instanceof PerspectiveCamera ) {
      if (INTOUCHDEVICE) {
        scale = dollyScale;
      } else {
        scale /= dollyScale;
      }
    // } else
    if ( scope.object instanceof OrthographicCamera ) {
      console.log('dollyIn:   ', dollyScale);
      if (INTOUCHDEVICE) {
        scale = (2 - dollyScale / scope.object.zoom);
      }


      let zoom = scope.object.zoom;
      if (INTOUCHDEVICE) {
        zoom = dollyScale;
      } else {
        zoom = scope.object.zoom * dollyScale;
      }
      scope.object.zoom = Math.max( scope.minZoom, Math.min( scope.maxZoom, zoom ) );
      scope.object.updateProjectionMatrix();
      zoomChanged = true;

    }
    //  else {

    //   console.warn( 'WARNING: OrbitControls.js encountered an unknown camera type - dolly/zoom disabled.' );
    //   scope.enableZoom = false;

    // }

  }

  function dollyOut( dollyScale ) {
    // console.log()
    // if ( scope.object instanceof PerspectiveCamera ) {
      if (INTOUCHDEVICE) {
        scale = dollyScale;
      } else {
        scale *= dollyScale;
      }
    // } else
    if ( scope.object instanceof OrthographicCamera ) {
      console.log('dollyOut:   ', dollyScale);
      if (INTOUCHDEVICE) {
        scale = (2 - dollyScale / scope.object.zoom);
      }

      let zoom = scope.object.zoom;
      if (INTOUCHDEVICE) {
        zoom = dollyScale;
      } else {
        zoom = scope.object.zoom / dollyScale;
      }
      scope.object.zoom = Math.max( scope.minZoom, Math.min( scope.maxZoom, zoom) );
      scope.object.updateProjectionMatrix();
      zoomChanged = true;

    }
    // else {

    //   console.warn( 'WARNING: OrbitControls.js encountered an unknown camera type - dolly/zoom disabled.' );
    //   scope.enableZoom = false;

    // }

  }

  //
  // event callbacks - update the object state
  //

  function handleMouseDownRotate( event ) {

    //console.log( 'handleMouseDownRotate' );

    rotateStart.set( event.clientX, event.clientY );

  }

  function handleMouseDownDolly( event ) {

    //console.log( 'handleMouseDownDolly' );

    dollyStart.set( event.clientX, event.clientY );

  }

  function handleMouseDownPan( event ) {

    //console.log( 'handleMouseDownPan' );

    panStart.set( event.clientX, event.clientY );

  }

  function handleMouseMoveRotate( event ) {

    //console.log( 'handleMouseMoveRotate' );

    rotateEnd.set( event.clientX, event.clientY );
    rotateDelta.subVectors( rotateEnd, rotateStart );

    var element = scope.domElement === document ? scope.domElement.body : scope.domElement;

    // rotating across whole screen goes 360 degrees around
    // 这是在转一个椭圆，将deltax映射成为弧度，类似于用周长代表角度
    rotateLeft( 2 * Math.PI * rotateDelta.x / element.clientWidth * scope.rotateSpeed );

    // rotating up and down along whole screen attempts to go 360, but limited to 180
    rotateUp( 2 * Math.PI * rotateDelta.y / element.clientHeight * scope.rotateSpeed );

    rotateStart.copy( rotateEnd );

    scope.update();

  }

  function handleMouseMoveDolly( event ) {

    //console.log( 'handleMouseMoveDolly' );

    dollyEnd.set( event.clientX, event.clientY );

    dollyDelta.subVectors( dollyEnd, dollyStart );

    if ( dollyDelta.y > 0 ) { // 竟然只是简单的用y来控制每次的缩放差

      dollyIn( getZoomScale() );

    } else if ( dollyDelta.y < 0 ) {

      dollyOut( getZoomScale() );

    }

    dollyStart.copy( dollyEnd );

    scope.update();

  }

  function handleMouseMovePan( event ) {

    //console.log( 'handleMouseMovePan' );

    panEnd.set( event.clientX, event.clientY );

    panDelta.subVectors( panEnd, panStart );

    pan( panDelta.x, panDelta.y );

    panStart.copy( panEnd );

    scope.update();

  }

  function handleMouseUp( event ) {

    // console.log( 'handleMouseUp' );

  }

  function handleMouseWheel( event ) {

    // console.log( 'handleMouseWheel' );

    if ( event.deltaY < 0 ) {

      dollyOut( getZoomScale() );

    } else if ( event.deltaY > 0 ) {

      dollyIn( getZoomScale() );

    }

    scope.update();

  }

  function handleKeyDown( event ) {

    //console.log( 'handleKeyDown' );

    switch ( event.keyCode ) {

      case scope.keys.UP:
        pan( 0, scope.keyPanSpeed );
        scope.update();
        break;

      case scope.keys.BOTTOM:
        pan( 0, - scope.keyPanSpeed );
        scope.update();
        break;

      case scope.keys.LEFT:
        pan( scope.keyPanSpeed, 0 );
        scope.update();
        break;

      case scope.keys.RIGHT:
        pan( - scope.keyPanSpeed, 0 );
        scope.update();
        break;

    }

  }

  function handleTouchStartRotate( event ) {

    //console.log( 'handleTouchStartRotate' );

    // rotateStart.set( event.touches[ 0 ].pageX, event.touches[ 0 ].pageY );

    var dx = event.touches[ 0 ].pageX - event.touches[ 1 ].pageX;
    var dy = event.touches[ 0 ].pageY - event.touches[ 1 ].pageY;
    touchThetaRotateStart.set(dx, dy);

    touchPhiFingerStart1.set(event.touches[0].pageX, event.touches[0].pageY);
    touchPhiFingerStart2.set(event.touches[1].pageX, event.touches[1].pageY);
  }

  function handleTouchStartDolly( event ) {

    //console.log( 'handleTouchStartDolly' );

    var dx = event.touches[ 0 ].pageX - event.touches[ 1 ].pageX;
    var dy = event.touches[ 0 ].pageY - event.touches[ 1 ].pageY;

    var distance = Math.sqrt( dx * dx + dy * dy );

    dollyStart.set( 0, distance );// touch情况下只是用两指之间距离来控制delta scale

  }

  function handleTouchStartPan( event ) {

    //console.log( 'handleTouchStartPan' );

    panStart.set( event.touches[ 0 ].pageX, event.touches[ 0 ].pageY );

  }


  function handleTouchMoveRotate( event ) {
    var dx = event.touches[0].pageX - event.touches[1].pageX;
    var dy = event.touches[0].pageY - event.touches[1].pageY;
    touchThetaRotateEnd.set(dx, dy);
    var element = scope.domElement === document ? scope.domElement.body : scope.domElement;

    touchPhiFingerEnd1.set(event.touches[0].pageX, event.touches[0].pageY);
    touchPhiFingerEnd2.set(event.touches[1].pageX, event.touches[1].pageY);
    let deltaPhi = Math.PI *
    (touchPhiFingerEnd1.y - touchPhiFingerStart1.y +
      touchPhiFingerEnd2.y - touchPhiFingerStart2.y) /
      2 / element.clientHeight;
      // console.log(deltaPhi);
    if (Math.abs(deltaPhi) > 0.01) {
      rotateUp(deltaPhi);
    }

    var costheta = touchThetaRotateEnd.dot(touchThetaRotateStart) /
      (touchThetaRotateStart.length() * touchThetaRotateEnd.length());
    // console.log('costheta', costheta);
    var cross = touchThetaRotateStart.x * touchThetaRotateEnd.y -
      touchThetaRotateEnd.x * touchThetaRotateStart.y;
    // console.log('cross', cross);
    var theta = Math.acos(costheta);
    // console.log('theta', theta);
    // 防止浮点数精度问题引发问题，比如Math.acos(1.000000000000002);
    theta = typeof theta === 'number' && isFinite(theta) ? theta : 0;
    if (Math.abs(theta) > 0.01) {
      sphericalDelta.theta = cross >= 0 ? theta : -theta;
    }

    touchThetaRotateStart.copy(touchThetaRotateEnd);
    touchPhiFingerStart1.copy(touchPhiFingerEnd1);
    touchPhiFingerStart2.copy(touchPhiFingerEnd2);

    scope.update();
  }

  function handleTouchMoveDolly( event ) {

    // console.log( 'handleTouchMoveDolly' );

    var dx = event.touches[ 0 ].pageX - event.touches[ 1 ].pageX;
    var dy = event.touches[ 0 ].pageY - event.touches[ 1 ].pageY;

    var distance = Math.sqrt( dx * dx + dy * dy );

    dollyEnd.set( 0, distance );

    dollyDelta.subVectors( dollyEnd, dollyStart );
    // console.log(dollyDelta, dollyStart);
    // console.log('handleTouchMoveDolly:   ', (1 - dollyDelta.y / dollyStart.y));
    if (scope.object instanceof PerspectiveCamera) {
      if ( dollyDelta.y > 0 ) {
        dollyOut( 1 - dollyDelta.y / dollyStart.y );
      } else if ( dollyDelta.y < 0 ) {
        dollyIn( 1 - dollyDelta.y / dollyStart.y );
      }
    } else if (scope.object instanceof OrthographicCamera) {

      if ( dollyDelta.y > 0 ) {
        dollyOut(scope.object.zoom * (1 + dollyDelta.y / dollyStart.y));
      } else if ( dollyDelta.y < 0 ) {
        dollyIn(scope.object.zoom * ( 1 + dollyDelta.y / dollyStart.y ));
      }
    }
      dollyStart.copy( dollyEnd );



    scope.update();

  }

  function handleTouchMovePan( event ) {

    // console.log( 'handleTouchMovePan' );

    panEnd.set( event.touches[ 0 ].pageX, event.touches[ 0 ].pageY );

    panDelta.subVectors( panEnd, panStart );

    pan( panDelta.x, panDelta.y );

    panStart.copy( panEnd );

    scope.update();

  }

  function handleTouchEnd( event ) {

    //console.log( 'handleTouchEnd' );

  }

  //
  // event handlers - FSM: listen for events and reset state
  //

  function onMouseDown( event ) {

    if ( scope.enabled === false ) return;

    event.preventDefault();

    switch ( event.button ) {

      case scope.mouseButtons.ORBIT:

        if ( scope.enableRotate === false ) return;

        handleMouseDownRotate( event );

        state = STATE.ROTATE;

        break;

      case scope.mouseButtons.ZOOM:

        if ( scope.enableZoom === false ) return;

        handleMouseDownDolly( event );

        state = STATE.DOLLY;

        break;

      case scope.mouseButtons.PAN:

        if ( scope.enablePan === false ) return;

        handleMouseDownPan( event );

        state = STATE.PAN;

        break;

    }

    if ( state !== STATE.NONE ) {

      document.addEventListener( 'mousemove', onMouseMove, false );
      document.addEventListener( 'mouseup', onMouseUp, false );

      scope.dispatchEvent( startEvent );

    }

  }

  function onMouseMove( event ) {

    if ( scope.enabled === false ) return;

    event.preventDefault();

    switch ( state ) {

      case STATE.ROTATE:

        if ( scope.enableRotate === false ) return;

        handleMouseMoveRotate( event );

        break;

      case STATE.DOLLY:

        if ( scope.enableZoom === false ) return;

        handleMouseMoveDolly( event );

        break;

      case STATE.PAN:

        if ( scope.enablePan === false ) return;

        handleMouseMovePan( event );

        break;

    }

  }

  function onMouseUp( event ) {

    if ( scope.enabled === false ) return;

    handleMouseUp( event );

    document.removeEventListener( 'mousemove', onMouseMove, false );
    document.removeEventListener( 'mouseup', onMouseUp, false );

    scope.dispatchEvent( endEvent );

    state = STATE.NONE;

  }

  function onMouseWheel( event ) {

    if ( scope.enabled === false || scope.enableZoom === false || ( state !== STATE.NONE && state !== STATE.ROTATE ) ) return;

    event.preventDefault();
    event.stopPropagation();

    handleMouseWheel( event );

    scope.dispatchEvent( startEvent ); // not sure why these are here...
    scope.dispatchEvent( endEvent );

  }

  function onKeyDown( event ) {

    if ( scope.enabled === false || scope.enableKeys === false || scope.enablePan === false ) return;

    handleKeyDown( event );

  }

  function onTouchStart( event ) {
    if ( scope.enabled === false ) return;
    console.log('OrbitControls+_start');

    switch ( event.touches.length ) {

      // case 1: // one-fingered touch: rotate

      //   if ( scope.enableRotate === false ) return;

      //   handleTouchStartRotate( event );

      //   state = STATE.TOUCH_ROTATE;

      //   break;

      case 2: // two-fingered touch: dolly or rotate

        // if ( scope.enableZoom === false ) return;

        // handleTouchStartDolly( event );

        // state = STATE.TOUCH_DOLLY;
        touchStartTime = Date.now();
        if (scope.enableZoom) {
          handleTouchStartDolly( event );
        }
        if (scope.enableRotate) {
          handleTouchStartRotate( event );
        }
        state = STATE.NONE;
        break;

      case 1: // one-fingered touch: pan

        if ( scope.enablePan === false ) return;

        handleTouchStartPan( event );

        state = STATE.TOUCH_PAN;

        break;

      default:

        state = STATE.NONE;

    }

    if ( state !== STATE.NONE ) {

      scope.dispatchEvent( startEvent );

    }

  }

  function onTouchMove( event ) {
    // console.log('OrbitControls+_move');

    if ( scope.enabled === false ) return;

    event.preventDefault();
    event.stopPropagation();

    switch ( event.touches.length ) {

      // case 1: // one-fingered touch: rotate

      //   if ( scope.enableRotate === false ) return;
      //   if ( state !== STATE.TOUCH_ROTATE ) return; // is this needed?...

      //   handleTouchMoveRotate( event );

      //   break;

      case 2: // two-fingered touch: dolly

        // if ( scope.enableZoom === false ) return;
        // if ( state !== STATE.TOUCH_DOLLY ) return; // is this needed?...

        handleTouchMoveDolly( event );
        handleTouchMoveRotate(event);

        // if (state === STATE.NONE) {
        //   var now = Date.now();
        //   // 如果双指在50ms内进行了缩放操作则记录state为dolly
        //   // 否则为Pan，在移动时无论是Pan还是dolly都会同时处理移动和缩放
        //   if (now - touchStartTime >= 200) {
        //     // 记录移动距离
        //     var dx = event.touches[ 0 ].pageX - event.touches[ 1 ].pageX;
        //     var dy = event.touches[ 0 ].pageY - event.touches[ 1 ].pageY;
        //     var distance = Math.sqrt( dx * dx + dy * dy );
        //     dollyEnd.set( 0, distance );
        //     dollyDelta.subVectors( dollyEnd, dollyStart );
        //     let dollyLength = dollyDelta.length();

        //     touchThetaRotateEnd.set(dx, dy);
        //     var costheta = touchThetaRotateEnd.dot(touchThetaRotateStart) / (touchThetaRotateStart.length() * touchThetaRotateEnd.length());
        //     var theta = Math.acos(costheta);

        //     touchPhiFingerEnd1.set(event.touches[0].pageX, event.touches[0].pageY);
        //     touchPhiFingerEnd2.set(event.touches[1].pageX, event.touches[1].pageY);

        //     if (Math.abs(dollyLength) >= 10) {
        //       state = STATE.TOUCH_DOLLY; // 既可以缩放又可以theta旋转

        //     } else if (theta > 5 * Math.PI / 180) {
        //       state = STATE.TOUCH_ROTATE_THETA;
        //     } else if (Math.abs(touchPhiFingerEnd1.x - touchPhiFingerStart1.x) < 5 &&
        //       Math.abs(touchPhiFingerEnd2.x - touchPhiFingerStart2.x) < 5 &&
        //       (Math.abs(touchPhiFingerEnd1.y - touchPhiFingerStart1.y) > 5) &&
        //       (Math.abs(touchPhiFingerEnd2.y - touchPhiFingerStart2.y) > 5)) {
        //       state = STATE.TOUCH_ROTATE_PHI;
        //     }
        //     dollyStart.copy(dollyEnd);
        //     dollyDelta.subVectors(dollyEnd, dollyStart);
        //     touchThetaRotateStart.copy(touchThetaRotateEnd);
        //     touchPhiFingerStart1.copy(touchPhiFingerEnd1);
        //     touchPhiFingerStart2.copy(touchPhiFingerEnd2);
        //   } else if (now - touchStartTime >= 400) {
        //     state = STATE.TOUCH_DOLLY;
        //   } else {
        //     state = STATE.NONE;
        //   }
        // } else if (state === STATE.TOUCH_DOLLY && scope.enableZoom) {
        //   handleTouchMoveDolly(event);
        //   handleTouchMoveRotate(event);
        // } else if ((state === STATE.TOUCH_ROTATE ||
        //   state === STATE.TOUCH_ROTATE_THETA || state === STATE.TOUCH_ROTATE_PHI) &&
        //   scope.enableRotate) {
        //   if (state === STATE.TOUCH_ROTATE_THETA) {
        //     handleTouchMoveDolly(event);
        //   }
        //   handleTouchMoveRotate(event);
        // }
        break;

      case 1: // one-fingered touch: pan

        if ( scope.enablePan === false ) return;
        // if ( state !== STATE.TOUCH_PAN ) return; // is this needed?...
        if (state !== STATE.TOUCH_PAN) {// 处理突然由两指变成单指情况
          handleTouchStartPan( event );
        } else {
          handleTouchMovePan( event );
        }

        state = STATE.TOUCH_PAN;

        break;

      default:

        state = STATE.NONE;

    }

  }

  function onTouchEnd( event ) {

    if ( scope.enabled === false ) return;

    handleTouchEnd( event );

    scope.dispatchEvent( endEvent );

    state = STATE.NONE;

  }

  function onContextMenu( event ) {

    event.preventDefault();

  }


  if (INTOUCHDEVICE) {
    scope.domElement.addEventListener( 'touchstart', onTouchStart, false );
    scope.domElement.addEventListener( 'touchend', onTouchEnd, false );
    scope.domElement.addEventListener( 'touchmove',
      onTouchMove
    , false );
  } else {
    scope.domElement.addEventListener( 'contextmenu', onContextMenu, false );
    scope.domElement.addEventListener( 'mousedown', onMouseDown, false );
    scope.domElement.addEventListener( 'wheel', onMouseWheel, false );
    window.addEventListener( 'keydown', onKeyDown, false );
  }

  // force an update at start

  this.update();

  this.pan = pan;
  this.rotate = function(theta, phi) {
    if (typeof theta === 'number' && isFinite(theta)) {
      sphericalDelta.theta -= theta;
    }
    if (typeof phi === 'number' && isFinite(phi)) {
      sphericalDelta.phi -= phi;
    }

    scope.update();
  };
  this.getMinDistanceByZoom = function() {
    return getDistanceByPixelMeterRatio(zoomRange[zoomRange.length - 1]);
  };
  this.getMaxDistanceByZoom = function() {
    return getDistanceByPixelMeterRatio(zoomRange[0]);
  };
  this.getDistanceByZoom = function(zoom) {
    // zoom代表数据侧zoom：1-7
    return getDistanceByPixelMeterRatio(zoomRange[zoom - 1]);
  };
  this.getZoomByDistance = function(distance) {
    var meterPerPixel = getPixelMeterRatioByDistance(distance);

    var mapZoom = getZoomRangeByRatio(meterPerPixel);
    return mapZoom;
  };
};
OrbitControls = OrbitControls;
OrbitControls.prototype = Object.create( EventDispatcher.prototype );
OrbitControls.prototype.constructor = OrbitControls;

Object.defineProperties( OrbitControls.prototype, {

  center: {

    get: function () {

      console.warn( 'OrbitControls: .center has been renamed to .target' );
      return this.target;

    }

  },

  // backward compatibility

  noZoom: {

    get: function () {

      console.warn( 'OrbitControls: .noZoom has been deprecated. Use .enableZoom instead.' );
      return ! this.enableZoom;

    },

    set: function ( value ) {

      console.warn( 'OrbitControls: .noZoom has been deprecated. Use .enableZoom instead.' );
      this.enableZoom = ! value;

    }

  },

  noRotate: {

    get: function () {

      console.warn( 'OrbitControls: .noRotate has been deprecated. Use .enableRotate instead.' );
      return ! this.enableRotate;

    },

    set: function ( value ) {

      console.warn( 'OrbitControls: .noRotate has been deprecated. Use .enableRotate instead.' );
      this.enableRotate = ! value;

    }

  },

  noPan: {

    get: function () {

      console.warn( 'OrbitControls: .noPan has been deprecated. Use .enablePan instead.' );
      return ! this.enablePan;

    },

    set: function ( value ) {

      console.warn( 'OrbitControls: .noPan has been deprecated. Use .enablePan instead.' );
      this.enablePan = ! value;

    }

  },

  noKeys: {

    get: function () {

      console.warn( 'OrbitControls: .noKeys has been deprecated. Use .enableKeys instead.' );
      return ! this.enableKeys;

    },

    set: function ( value ) {

      console.warn( 'OrbitControls: .noKeys has been deprecated. Use .enableKeys instead.' );
      this.enableKeys = ! value;

    }

  },

  staticMoving: {

    get: function () {

      console.warn( 'OrbitControls: .staticMoving has been deprecated. Use .enableDamping instead.' );
      return ! this.enableDamping;

    },

    set: function ( value ) {

      console.warn( 'OrbitControls: .staticMoving has been deprecated. Use .enableDamping instead.' );
      this.enableDamping = ! value;

    }

  },

  dynamicDampingFactor: {

    get: function () {

      console.warn( 'OrbitControls: .dynamicDampingFactor has been renamed. Use .dampingFactor instead.' );
      return this.dampingFactor;

    },

    set: function ( value ) {

      console.warn( 'OrbitControls: .dynamicDampingFactor has been renamed. Use .dampingFactor instead.' );
      this.dampingFactor = value;

    }

  }

} );



  }


  function handleTouchMoveRotate( event ) {
    var dx = event.touches[0].pageX - event.touches[1].pageX;
    var dy = event.touches[0].pageY - event.touches[1].pageY;
    touchThetaRotateEnd.set(dx, dy);
    var element = scope.domElement === document ? scope.domElement.body : scope.domElement;

    touchPhiFingerEnd1.set(event.touches[0].pageX, event.touches[0].pageY);
    touchPhiFingerEnd2.set(event.touches[1].pageX, event.touches[1].pageY);
    let deltaPhi = Math.PI *
    (touchPhiFingerEnd1.y - touchPhiFingerStart1.y +
      touchPhiFingerEnd2.y - touchPhiFingerStart2.y) /
      2 / element.clientHeight;
      // console.log(deltaPhi);
    if (Math.abs(deltaPhi) > 0.01) {
      rotateUp(deltaPhi);
    }

    var costheta = touchThetaRotateEnd.dot(touchThetaRotateStart) /
      (touchThetaRotateStart.length() * touchThetaRotateEnd.length());
    // console.log('costheta', costheta);
    var cross = touchThetaRotateStart.x * touchThetaRotateEnd.y -
      touchThetaRotateEnd.x * touchThetaRotateStart.y;
    // console.log('cross', cross);
    var theta = Math.acos(costheta);
    // console.log('theta', theta);
    // 防止浮点数精度问题引发问题，比如Math.acos(1.000000000000002);
    theta = typeof theta === 'number' && isFinite(theta) ? theta : 0;
    if (Math.abs(theta) > 0.01) {
      sphericalDelta.theta = cross >= 0 ? theta : -theta;
    }

    touchThetaRotateStart.copy(touchThetaRotateEnd);
    touchPhiFingerStart1.copy(touchPhiFingerEnd1);
    touchPhiFingerStart2.copy(touchPhiFingerEnd2);

    scope.update();
  }

  function handleTouchMoveDolly( event ) {

    // console.log( 'handleTouchMoveDolly' );

    var dx = event.touches[ 0 ].pageX - event.touches[ 1 ].pageX;
    var dy = event.touches[ 0 ].pageY - event.touches[ 1 ].pageY;

    var distance = Math.sqrt( dx * dx + dy * dy );

    dollyEnd.set( 0, distance );

    dollyDelta.subVectors( dollyEnd, dollyStart );
    // console.log(dollyDelta, dollyStart);
    // console.log('handleTouchMoveDolly:   ', (1 - dollyDelta.y / dollyStart.y));
    if (scope.object instanceof PerspectiveCamera) {
      if ( dollyDelta.y > 0 ) {
        dollyOut( 1 - dollyDelta.y / dollyStart.y );
      } else if ( dollyDelta.y < 0 ) {
        dollyIn( 1 - dollyDelta.y / dollyStart.y );
      }
    } else if (scope.object instanceof OrthographicCamera) {

      if ( dollyDelta.y > 0 ) {
        dollyOut(scope.object.zoom * (1 + dollyDelta.y / dollyStart.y));
      } else if ( dollyDelta.y < 0 ) {
        dollyIn(scope.object.zoom * ( 1 + dollyDelta.y / dollyStart.y ));
      }
    }
      dollyStart.copy( dollyEnd );



    scope.update();

  }

  function handleTouchMovePan( event ) {

    // console.log( 'handleTouchMovePan' );

    panEnd.set( event.touches[ 0 ].pageX, event.touches[ 0 ].pageY );

    panDelta.subVectors( panEnd, panStart );

    pan( panDelta.x, panDelta.y );

    panStart.copy( panEnd );

    scope.update();

  }

  function handleTouchEnd( event ) {

    //console.log( 'handleTouchEnd' );

  }

  //
  // event handlers - FSM: listen for events and reset state
  //

  function onMouseDown( event ) {

    if ( scope.enabled === false ) return;

    event.preventDefault();

    switch ( event.button ) {

      case scope.mouseButtons.ORBIT:

        if ( scope.enableRotate === false ) return;

        handleMouseDownRotate( event );

        state = STATE.ROTATE;

        break;

      case scope.mouseButtons.ZOOM:

        if ( scope.enableZoom === false ) return;

        handleMouseDownDolly( event );

        state = STATE.DOLLY;

        break;

      case scope.mouseButtons.PAN:

        if ( scope.enablePan === false ) return;

        handleMouseDownPan( event );

        state = STATE.PAN;

        break;

    }

    if ( state !== STATE.NONE ) {

      document.addEventListener( 'mousemove', onMouseMove, false );
      document.addEventListener( 'mouseup', onMouseUp, false );

      scope.dispatchEvent( startEvent );

    }

  }

  function onMouseMove( event ) {

    if ( scope.enabled === false ) return;

    event.preventDefault();

    switch ( state ) {

      case STATE.ROTATE:

        if ( scope.enableRotate === false ) return;

        handleMouseMoveRotate( event );

        break;

      case STATE.DOLLY:

        if ( scope.enableZoom === false ) return;

        handleMouseMoveDolly( event );

        break;

      case STATE.PAN:

        if ( scope.enablePan === false ) return;

        handleMouseMovePan( event );

        break;

    }

  }

  function onMouseUp( event ) {

    if ( scope.enabled === false ) return;

    handleMouseUp( event );

    document.removeEventListener( 'mousemove', onMouseMove, false );
    document.removeEventListener( 'mouseup', onMouseUp, false );

    scope.dispatchEvent( endEvent );

    state = STATE.NONE;

  }

  function onMouseWheel( event ) {

    if ( scope.enabled === false || scope.enableZoom === false || ( state !== STATE.NONE && state !== STATE.ROTATE ) ) return;

    event.preventDefault();
    event.stopPropagation();

    handleMouseWheel( event );

    scope.dispatchEvent( startEvent ); // not sure why these are here...
    scope.dispatchEvent( endEvent );

  }

  function onKeyDown( event ) {

    if ( scope.enabled === false || scope.enableKeys === false || scope.enablePan === false ) return;

    handleKeyDown( event );

  }

  function onTouchStart( event ) {
    if ( scope.enabled === false ) return;
    console.log('OrbitControls+_start');

    switch ( event.touches.length ) {

      // case 1: // one-fingered touch: rotate

      //   if ( scope.enableRotate === false ) return;

      //   handleTouchStartRotate( event );

      //   state = STATE.TOUCH_ROTATE;

      //   break;

      case 2: // two-fingered touch: dolly or rotate

        // if ( scope.enableZoom === false ) return;

        // handleTouchStartDolly( event );

        // state = STATE.TOUCH_DOLLY;
        touchStartTime = Date.now();
        if (scope.enableZoom) {
          handleTouchStartDolly( event );
        }
        if (scope.enableRotate) {
          handleTouchStartRotate( event );
        }
        state = STATE.NONE;
        break;

      case 1: // one-fingered touch: pan

        if ( scope.enablePan === false ) return;

        handleTouchStartPan( event );

        state = STATE.TOUCH_PAN;

        break;

      default:

        state = STATE.NONE;

    }

    if ( state !== STATE.NONE ) {

      scope.dispatchEvent( startEvent );

    }

  }

  function onTouchMove( event ) {
    // console.log('OrbitControls+_move');

    if ( scope.enabled === false ) return;

    event.preventDefault();
    event.stopPropagation();

    switch ( event.touches.length ) {

      // case 1: // one-fingered touch: rotate

      //   if ( scope.enableRotate === false ) return;
      //   if ( state !== STATE.TOUCH_ROTATE ) return; // is this needed?...

      //   handleTouchMoveRotate( event );

      //   break;

      case 2: // two-fingered touch: dolly

        // if ( scope.enableZoom === false ) return;
        // if ( state !== STATE.TOUCH_DOLLY ) return; // is this needed?...

        handleTouchMoveDolly( event );
        handleTouchMoveRotate(event);

        // if (state === STATE.NONE) {
        //   var now = Date.now();
        //   // 如果双指在50ms内进行了缩放操作则记录state为dolly
        //   // 否则为Pan，在移动时无论是Pan还是dolly都会同时处理移动和缩放
        //   if (now - touchStartTime >= 200) {
        //     // 记录移动距离
        //     var dx = event.touches[ 0 ].pageX - event.touches[ 1 ].pageX;
        //     var dy = event.touches[ 0 ].pageY - event.touches[ 1 ].pageY;
        //     var distance = Math.sqrt( dx * dx + dy * dy );
        //     dollyEnd.set( 0, distance );
        //     dollyDelta.subVectors( dollyEnd, dollyStart );
        //     let dollyLength = dollyDelta.length();

        //     touchThetaRotateEnd.set(dx, dy);
        //     var costheta = touchThetaRotateEnd.dot(touchThetaRotateStart) / (touchThetaRotateStart.length() * touchThetaRotateEnd.length());
        //     var theta = Math.acos(costheta);

        //     touchPhiFingerEnd1.set(event.touches[0].pageX, event.touches[0].pageY);
        //     touchPhiFingerEnd2.set(event.touches[1].pageX, event.touches[1].pageY);

        //     if (Math.abs(dollyLength) >= 10) {
        //       state = STATE.TOUCH_DOLLY; // 既可以缩放又可以theta旋转

        //     } else if (theta > 5 * Math.PI / 180) {
        //       state = STATE.TOUCH_ROTATE_THETA;
        //     } else if (Math.abs(touchPhiFingerEnd1.x - touchPhiFingerStart1.x) < 5 &&
        //       Math.abs(touchPhiFingerEnd2.x - touchPhiFingerStart2.x) < 5 &&
        //       (Math.abs(touchPhiFingerEnd1.y - touchPhiFingerStart1.y) > 5) &&
        //       (Math.abs(touchPhiFingerEnd2.y - touchPhiFingerStart2.y) > 5)) {
        //       state = STATE.TOUCH_ROTATE_PHI;
        //     }
        //     dollyStart.copy(dollyEnd);
        //     dollyDelta.subVectors(dollyEnd, dollyStart);
        //     touchThetaRotateStart.copy(touchThetaRotateEnd);
        //     touchPhiFingerStart1.copy(touchPhiFingerEnd1);
        //     touchPhiFingerStart2.copy(touchPhiFingerEnd2);
        //   } else if (now - touchStartTime >= 400) {
        //     state = STATE.TOUCH_DOLLY;
        //   } else {
        //     state = STATE.NONE;
        //   }
        // } else if (state === STATE.TOUCH_DOLLY && scope.enableZoom) {
        //   handleTouchMoveDolly(event);
        //   handleTouchMoveRotate(event);
        // } else if ((state === STATE.TOUCH_ROTATE ||
        //   state === STATE.TOUCH_ROTATE_THETA || state === STATE.TOUCH_ROTATE_PHI) &&
        //   scope.enableRotate) {
        //   if (state === STATE.TOUCH_ROTATE_THETA) {
        //     handleTouchMoveDolly(event);
        //   }
        //   handleTouchMoveRotate(event);
        // }
        break;

      case 1: // one-fingered touch: pan

        if ( scope.enablePan === false ) return;
        // if ( state !== STATE.TOUCH_PAN ) return; // is this needed?...
        if (state !== STATE.TOUCH_PAN) {// 处理突然由两指变成单指情况
          handleTouchStartPan( event );
        } else {
          handleTouchMovePan( event );
        }

        state = STATE.TOUCH_PAN;

        break;

      default:

        state = STATE.NONE;

    }

  }

  function onTouchEnd( event ) {

    if ( scope.enabled === false ) return;

    handleTouchEnd( event );

    scope.dispatchEvent( endEvent );

    state = STATE.NONE;

  }

  function onContextMenu( event ) {

    event.preventDefault();

  }


  if (INTOUCHDEVICE) {
    scope.domElement.addEventListener( 'touchstart', onTouchStart, false );
    scope.domElement.addEventListener( 'touchend', onTouchEnd, false );
    scope.domElement.addEventListener( 'touchmove',
      onTouchMove
    , false );
  } else {
    scope.domElement.addEventListener( 'contextmenu', onContextMenu, false );
    scope.domElement.addEventListener( 'mousedown', onMouseDown, false );
    scope.domElement.addEventListener( 'wheel', onMouseWheel, false );
    window.addEventListener( 'keydown', onKeyDown, false );
  }

  // force an update at start

  this.update();

  this.pan = pan;
  this.rotate = function(theta, phi) {
    if (typeof theta === 'number' && isFinite(theta)) {
      sphericalDelta.theta -= theta;
    }
    if (typeof phi === 'number' && isFinite(phi)) {
      sphericalDelta.phi -= phi;
    }

    scope.update();
  };
  this.getMinDistanceByZoom = function() {
    return getDistanceByPixelMeterRatio(zoomRange[zoomRange.length - 1]);
  };
  this.getMaxDistanceByZoom = function() {
    return getDistanceByPixelMeterRatio(zoomRange[0]);
  }

};
OrbitControls = OrbitControls;
OrbitControls.prototype = Object.create( EventDispatcher.prototype );
OrbitControls.prototype.constructor = OrbitControls;

Object.defineProperties( OrbitControls.prototype, {

  center: {

    get: function () {

      console.warn( 'OrbitControls: .center has been renamed to .target' );
      return this.target;

    }

  },

  // backward compatibility

  noZoom: {

    get: function () {

      console.warn( 'OrbitControls: .noZoom has been deprecated. Use .enableZoom instead.' );
      return ! this.enableZoom;

    },

    set: function ( value ) {

      console.warn( 'OrbitControls: .noZoom has been deprecated. Use .enableZoom instead.' );
      this.enableZoom = ! value;

    }

  },

  noRotate: {

    get: function () {

      console.warn( 'OrbitControls: .noRotate has been deprecated. Use .enableRotate instead.' );
      return ! this.enableRotate;

    },

    set: function ( value ) {

      console.warn( 'OrbitControls: .noRotate has been deprecated. Use .enableRotate instead.' );
      this.enableRotate = ! value;

    }

  },

  noPan: {

    get: function () {

      console.warn( 'OrbitControls: .noPan has been deprecated. Use .enablePan instead.' );
      return ! this.enablePan;

    },

    set: function ( value ) {

      console.warn( 'OrbitControls: .noPan has been deprecated. Use .enablePan instead.' );
      this.enablePan = ! value;

    }

  },

  noKeys: {

    get: function () {

      console.warn( 'OrbitControls: .noKeys has been deprecated. Use .enableKeys instead.' );
      return ! this.enableKeys;

    },

    set: function ( value ) {

      console.warn( 'OrbitControls: .noKeys has been deprecated. Use .enableKeys instead.' );
      this.enableKeys = ! value;

    }

  },

  staticMoving: {

    get: function () {

      console.warn( 'OrbitControls: .staticMoving has been deprecated. Use .enableDamping instead.' );
      return ! this.enableDamping;

    },

    set: function ( value ) {

      console.warn( 'OrbitControls: .staticMoving has been deprecated. Use .enableDamping instead.' );
      this.enableDamping = ! value;

    }

  },

  dynamicDampingFactor: {

    get: function () {

      console.warn( 'OrbitControls: .dynamicDampingFactor has been renamed. Use .dampingFactor instead.' );
      return this.dampingFactor;

    },

    set: function ( value ) {

      console.warn( 'OrbitControls: .dynamicDampingFactor has been renamed. Use .dampingFactor instead.' );
      this.dampingFactor = value;

    }

  }

} );