ami.js/src/controls/controls.trackball.js

<p align="center"> <img src="https://cloud.githubusercontent.com/assets/214063/23213764/78ade038-f90c-11e6-8208-4fcade5f3832.png" width="60%"> </p>

/**
 * Original authors from THREEJS repo
 * @author Eberhard Graether / http://egraether.com/
 * @author Mark Lundin  / http://mark-lundin.com
 * @author Simone Manini / http://daron1337.github.io
 * @author Luca Antiga  / http://lantiga.github.io
 */

import {EventDispatcher, Quaternion, Vector2, Vector3} from 'three';

 export default class Trackball extends EventDispatcher {
  constructor(object, domElement) {
    super();

    let _this = this;
    let STATE = {NONE: -1, ROTATE: 0, ZOOM: 1, PAN: 2, TOUCH_ROTATE: 3, TOUCH_ZOOM: 4, TOUCH_PAN: 5, CUSTOM: 99};

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

    // API

    this.enabled = true;

    this.screen = {left: 0, top: 0, width: 0, height: 0};

    this.rotateSpeed = 1.0;
    this.zoomSpeed = 1.2;
    this.panSpeed = 0.3;

    this.noRotate = false;
    this.noZoom = false;
    this.noPan = false;
    this.noCustom = false;

    this.forceState = -1;

    this.staticMoving = false;
    this.dynamicDampingFactor = 0.2;

    this.minDistance = 0;
    this.maxDistance = Infinity;

    this.keys = [65 /* A*/, 83 /* S*/, 68];

    // internals

    this.target = new Vector3();

    let EPS = 0.000001;

    let lastPosition = new Vector3();

    let _state = STATE.NONE,
    _prevState = STATE.NONE,

    _eye = new Vector3(),

    _movePrev = new Vector2(),
    _moveCurr = new Vector2(),

    _lastAxis = new Vector3(),
    _lastAngle = 0,

    _zoomStart = new Vector2(),
    _zoomEnd = new Vector2(),

    _touchZoomDistanceStart = 0,
    _touchZoomDistanceEnd = 0,

    _panStart = new Vector2(),
    _panEnd = new Vector2(),

    _customStart = new Vector2(),
    _customEnd = new Vector2();

    // for reset

    this.target0 = this.target.clone();
    this.position0 = this.object.position.clone();
    this.up0 = this.object.up.clone();

    // events

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

    // methods

    this.handleResize = function() {
      if (this.domElement === document) {
        this.screen.left = 0;
        this.screen.top = 0;
        this.screen.width = window.innerWidth;
        this.screen.height = window.innerHeight;
      } else {
        let box = this.domElement.getBoundingClientRect();
        // adjustments come from similar code in the jquery offset() function
        let d = this.domElement.ownerDocument.documentElement;
        this.screen.left = box.left + window.pageXOffset - d.clientLeft;
        this.screen.top = box.top + window.pageYOffset - d.clientTop;
        this.screen.width = box.width;
        this.screen.height = box.height;
      }
    };

    this.handleEvent = function(event) {
      if (typeof this[event.type] == 'function') {
        this[event.type](event);
      }
    };

    let getMouseOnScreen = (function() {
      let vector = new Vector2();

      return function(pageX, pageY) {
        vector.set(
            (pageX - _this.screen.left) / _this.screen.width,
            (pageY - _this.screen.top) / _this.screen.height
        );

        return vector;
      };
    }());

    let getMouseOnCircle = (function() {
      let vector = new Vector2();

      return function(pageX, pageY) {
        vector.set(
            ((pageX - _this.screen.width * 0.5 - _this.screen.left) / (_this.screen.width * 0.5)),
            ((_this.screen.height + 2 * (_this.screen.top - pageY)) / _this.screen.width) // screen.width intentional
        );

        return vector;
      };
    }());

    this.rotateCamera = (function() {
      let axis = new Vector3(),
          quaternion = new Quaternion(),
          eyeDirection = new Vector3(),
          objectUpDirection = new Vector3(),
          objectSidewaysDirection = new Vector3(),
          moveDirection = new Vector3(),
          angle;

      return function() {
        moveDirection.set(_moveCurr.x - _movePrev.x, _moveCurr.y - _movePrev.y, 0);
        angle = moveDirection.length();

        if (angle) {
          _eye.copy(_this.object.position).sub(_this.target);

          eyeDirection.copy(_eye).normalize();
          objectUpDirection.copy(_this.object.up).normalize();
          objectSidewaysDirection.crossVectors(objectUpDirection, eyeDirection).normalize();

          objectUpDirection.setLength(_moveCurr.y - _movePrev.y);
          objectSidewaysDirection.setLength(_moveCurr.x - _movePrev.x);

          moveDirection.copy(objectUpDirection.add(objectSidewaysDirection));

          axis.crossVectors(moveDirection, _eye).normalize();

          angle *= _this.rotateSpeed;
          quaternion.setFromAxisAngle(axis, angle);

          _eye.applyQuaternion(quaternion);
          _this.object.up.applyQuaternion(quaternion);

          _lastAxis.copy(axis);
          _lastAngle = angle;
        } else if (!_this.staticMoving && _lastAngle) {
          _lastAngle *= Math.sqrt(1.0 - _this.dynamicDampingFactor);
          _eye.copy(_this.object.position).sub(_this.target);
          quaternion.setFromAxisAngle(_lastAxis, _lastAngle);
          _eye.applyQuaternion(quaternion);
          _this.object.up.applyQuaternion(quaternion);
        }

        _movePrev.copy(_moveCurr);
      };
    }());

    this.zoomCamera = function() {
      let factor;

      if (_state === STATE.TOUCH_ZOOM) {
        factor = _touchZoomDistanceStart / _touchZoomDistanceEnd;
        _touchZoomDistanceStart = _touchZoomDistanceEnd;
        _eye.multiplyScalar(factor);
      } else {
        factor = 1.0 + (_zoomEnd.y - _zoomStart.y) * _this.zoomSpeed;

        if (factor !== 1.0 && factor > 0.0) {
          _eye.multiplyScalar(factor);

          if (_this.staticMoving) {
            _zoomStart.copy(_zoomEnd);
          } else {
            _zoomStart.y += (_zoomEnd.y - _zoomStart.y) * this.dynamicDampingFactor;
          }
        }
      }
    };

    this.panCamera = (function() {
      let mouseChange = new Vector2(),
          objectUp = new Vector3(),
          pan = new Vector3();

      return function() {
        mouseChange.copy(_panEnd).sub(_panStart);

        if (mouseChange.lengthSq()) {
          mouseChange.multiplyScalar(_eye.length() * _this.panSpeed);

          pan.copy(_eye).cross(_this.object.up).setLength(mouseChange.x);
          pan.add(objectUp.copy(_this.object.up).setLength(mouseChange.y));

          _this.object.position.add(pan);
          _this.target.add(pan);

          if (_this.staticMoving) {
            _panStart.copy(_panEnd);
          } else {
            _panStart.add(mouseChange.subVectors(_panEnd, _panStart).multiplyScalar(_this.dynamicDampingFactor));
          }
        }
      };
    }());

    this.checkDistances = function() {
      if (!_this.noZoom || !_this.noPan) {
        if (_eye.lengthSq() > _this.maxDistance * _this.maxDistance) {
          _this.object.position.addVectors(_this.target, _eye.setLength(_this.maxDistance));
        }

        if (_eye.lengthSq() < _this.minDistance * _this.minDistance) {
          _this.object.position.addVectors(_this.target, _eye.setLength(_this.minDistance));
        }
      }
    };

    this.update = function() {
      _eye.subVectors(_this.object.position, _this.target);

      if (!_this.noRotate) {
        _this.rotateCamera();
      }

      if (!_this.noZoom) {
        _this.zoomCamera();
      }

      if (!_this.noPan) {
        _this.panCamera();
      }

      if (!_this.noCustom) {
        _this.custom(_customStart, _customEnd);
      }

      _this.object.position.addVectors(_this.target, _eye);

      _this.checkDistances();

      _this.object.lookAt(_this.target);

      if (lastPosition.distanceToSquared(_this.object.position) > EPS) {
        _this.dispatchEvent(changeEvent);

        lastPosition.copy(_this.object.position);
      }
    };

    this.reset = function() {
      _state = STATE.NONE;
      _prevState = STATE.NONE;

      _this.target.copy(_this.target0);
      _this.object.position.copy(_this.position0);
      _this.object.up.copy(_this.up0);

      _eye.subVectors(_this.object.position, _this.target);

      _this.object.lookAt(_this.target);

      _this.dispatchEvent(changeEvent);

      lastPosition.copy(_this.object.position);
    };

    this.setState = function(targetState) {
      _this.forceState = targetState;
      _prevState = targetState;
      _state = targetState;
    };

    this.custom = function(customStart, customEnd) {

    };

    // listeners

    function keydown(event) {
      if (_this.enabled === false) return;

      window.removeEventListener('keydown', keydown);

      _prevState = _state;

      if (_state !== STATE.NONE) {
        return;
      } else if (event.keyCode === _this.keys[STATE.ROTATE] && !_this.noRotate) {
        _state = STATE.ROTATE;
      } else if (event.keyCode === _this.keys[STATE.ZOOM] && !_this.noZoom) {
        _state = STATE.ZOOM;
      } else if (event.keyCode === _this.keys[STATE.PAN] && !_this.noPan) {
        _state = STATE.PAN;
      }
    }

    function keyup(event) {
      if (_this.enabled === false) return;

      _state = _prevState;

      window.addEventListener('keydown', keydown, false);
    }

    function mousedown(event) {
      if (_this.enabled === false) return;

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

      if (_state === STATE.NONE) {
        _state = event.button;
      }

      if (_state === STATE.ROTATE && !_this.noRotate) {
        _moveCurr.copy(getMouseOnCircle(event.pageX, event.pageY));
        _movePrev.copy(_moveCurr);
      } else if (_state === STATE.ZOOM && !_this.noZoom) {
        _zoomStart.copy(getMouseOnScreen(event.pageX, event.pageY));
        _zoomEnd.copy(_zoomStart);
      } else if (_state === STATE.PAN && !_this.noPan) {
        _panStart.copy(getMouseOnScreen(event.pageX, event.pageY));
        _panEnd.copy(_panStart);
      } else if (_state === STATE.CUSTOM && !_this.noCustom) {
        _customStart.copy(getMouseOnScreen(event.pageX, event.pageY));
        _customEnd.copy(_panStart);
      }

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

      _this.dispatchEvent(startEvent);
    }

    function mousemove(event) {
      if (_this.enabled === false) return;

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

      if (_state === STATE.ROTATE && !_this.noRotate) {
        _movePrev.copy(_moveCurr);
        _moveCurr.copy(getMouseOnCircle(event.pageX, event.pageY));
      } else if (_state === STATE.ZOOM && !_this.noZoom) {
        _zoomEnd.copy(getMouseOnScreen(event.pageX, event.pageY));
      } else if (_state === STATE.PAN && !_this.noPan) {
        _panEnd.copy(getMouseOnScreen(event.pageX, event.pageY));
      } else if (_state === STATE.CUSTOM && !_this.noCustom) {
        _customEnd.copy(getMouseOnScreen(event.pageX, event.pageY));
      }
    }

    function mouseup(event) {
      if (_this.enabled === false) return;

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

      if (_this.forceState === -1) {
        _state = STATE.NONE;
      }

      document.removeEventListener('mousemove', mousemove);
      document.removeEventListener('mouseup', mouseup);
      _this.dispatchEvent(endEvent);
    }

    function mousewheel(event) {
      if (_this.enabled === false) return;

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

      let delta = 0;

      if (event.wheelDelta) {
 // WebKit / Opera / Explorer 9

        delta = event.wheelDelta / 40;
      } else if (event.detail) {
 // Firefox

        delta = -event.detail / 3;
      }

      if (_state !== STATE.CUSTOM) {
        _zoomStart.y += delta * 0.01;
      } else if (_state === STATE.CUSTOM) {
        _customStart.y += delta * 0.01;
      }

      _this.dispatchEvent(startEvent);
      _this.dispatchEvent(endEvent);
    }

    function touchstart(event) {
      if (_this.enabled === false) return;

      if (_this.forceState === -1) {
        switch (event.touches.length) {
          case 1:
            _state = STATE.TOUCH_ROTATE;
            _moveCurr.copy(getMouseOnCircle(event.touches[0].pageX, event.touches[0].pageY));
            _movePrev.copy(_moveCurr);
            break;

          case 2:
            _state = STATE.TOUCH_ZOOM;
            var dx = event.touches[0].pageX - event.touches[1].pageX;
            var dy = event.touches[0].pageY - event.touches[1].pageY;
            _touchZoomDistanceEnd = _touchZoomDistanceStart = Math.sqrt(dx * dx + dy * dy);

            var x = (event.touches[0].pageX + event.touches[1].pageX) / 2;
            var y = (event.touches[0].pageY + event.touches[1].pageY) / 2;
            _panStart.copy(getMouseOnScreen(x, y));
            _panEnd.copy(_panStart);
            break;

          default:
            _state = STATE.NONE;
        }
      } else {
        // { NONE: -1, ROTATE: 0, ZOOM: 1, PAN: 2, TOUCH_ROTATE: 3, TOUCH_ZOOM_PAN: 4, CUSTOM: 99 };
        switch (_state) {
          case 0:
            // 1 or 2 fingers, smae behavior
            _state = STATE.TOUCH_ROTATE;
            _moveCurr.copy(getMouseOnCircle(event.touches[0].pageX, event.touches[0].pageY));
            _movePrev.copy(_moveCurr);
            break;

          case 1:
          case 4:
            if (event.touches.length >= 2) {
              _state = STATE.TOUCH_ZOOM;
              var dx = event.touches[0].pageX - event.touches[1].pageX;
              var dy = event.touches[0].pageY - event.touches[1].pageY;
              _touchZoomDistanceEnd = _touchZoomDistanceStart = Math.sqrt(dx * dx + dy * dy);
            } else {
              _state = STATE.ZOOM;
              _zoomStart.copy(getMouseOnScreen(event.touches[0].pageX, event.touches[0].pageY));
              _zoomEnd.copy(_zoomStart);
            }
            break;

          case 2:
          case 5:
            if (event.touches.length >= 2) {
              _state = STATE.TOUCH_PAN;
              var x = (event.touches[0].pageX + event.touches[1].pageX) / 2;
              var y = (event.touches[0].pageY + event.touches[1].pageY) / 2;
              _panStart.copy(getMouseOnScreen(x, y));
              _panEnd.copy(_panStart);
            } else {
              _state = STATE.PAN;
              _panStart.copy(getMouseOnScreen(event.touches[0].pageX, event.touches[0].pageY));
              _panEnd.copy(_panStart);
            }
            break;

          case 99:
            _state = STATE.CUSTOM;
            var x = (event.touches[0].pageX + event.touches[1].pageX) / 2;
            var y = (event.touches[0].pageY + event.touches[1].pageY) / 2;
            _customStart.copy(getMouseOnScreen(x, y));
            _customEnd.copy(_customStart);
            break;

          default:
            _state = STATE.NONE;
        }
      }

      _this.dispatchEvent(startEvent);
    }

    function touchmove(event) {
      if (_this.enabled === false) return;

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

      if (_this.forceState === -1) {
        switch (event.touches.length) {
          case 1:
            _movePrev.copy(_moveCurr);
            _moveCurr.copy(getMouseOnCircle(event.touches[0].pageX, event.touches[0].pageY));
            break;

          case 2:
            var dx = event.touches[0].pageX - event.touches[1].pageX;
            var dy = event.touches[0].pageY - event.touches[1].pageY;
            _touchZoomDistanceEnd = Math.sqrt(dx * dx + dy * dy);

            var x = (event.touches[0].pageX + event.touches[1].pageX) / 2;
            var y = (event.touches[0].pageY + event.touches[1].pageY) / 2;
            _panEnd.copy(getMouseOnScreen(x, y));
            break;

          default:
            _state = STATE.NONE;
        }
      } else {
        // { NONE: -1, ROTATE: 0, ZOOM: 1, PAN: 2, TOUCH_ROTATE: 3, TOUCH_ZOOM_PAN: 4, CUSTOM: 99 };
        switch (_state) {
          case 0:
            _movePrev.copy(_moveCurr);
            _moveCurr.copy(getMouseOnCircle(event.touches[0].pageX, event.touches[0].pageY));
            break;

          case 1:
            _zoomEnd.copy(getMouseOnScreen(event.touches[0].pageX, event.touches[0].pageY));
            break;

          case 2:
            _panEnd.copy(getMouseOnScreen(event.touches[0].pageX, event.touches[0].pageY));
            break;

          case 4:
            // 2 fingers!
            // TOUCH ZOOM
            var dx = event.touches[0].pageX - event.touches[1].pageX;
            var dy = event.touches[0].pageY - event.touches[1].pageY;
            _touchZoomDistanceEnd = Math.sqrt(dx * dx + dy * dy);
            break;

          case 5:
            // 2 fingers
            // TOUCH_PAN
            var x = (event.touches[0].pageX + event.touches[1].pageX) / 2;
            var y = (event.touches[0].pageY + event.touches[1].pageY) / 2;
            _panEnd.copy(getMouseOnScreen(x, y));
            break;

          case 99:
            var x = (event.touches[0].pageX + event.touches[1].pageX) / 2;
            var y = (event.touches[0].pageY + event.touches[1].pageY) / 2;
            _customEnd.copy(getMouseOnScreen(x, y));
            break;

          default:
            _state = STATE.NONE;
        }
      }
    }

    function touchend(event) {
      if (_this.enabled === false) return;

      if (_this.forceState === -1) {
        switch (event.touches.length) {
          case 1:
            _movePrev.copy(_moveCurr);
            _moveCurr.copy(getMouseOnCircle(event.touches[0].pageX, event.touches[0].pageY));
            break;

          case 2:
            _touchZoomDistanceStart = _touchZoomDistanceEnd = 0;

            var x = (event.touches[0].pageX + event.touches[1].pageX) / 2;
            var y = (event.touches[0].pageY + event.touches[1].pageY) / 2;
            _panEnd.copy(getMouseOnScreen(x, y));
            _panStart.copy(_panEnd);
            break;
        }

        _state = STATE.NONE;
      } else {
        switch (_state) {
          case 0:
            _movePrev.copy(_moveCurr);
            _moveCurr.copy(getMouseOnCircle(event.touches[0].pageX, event.touches[0].pageY));
            break;

          case 1:
          case 2:
            break;

          case 4:
            // TOUCH ZOOM
            _touchZoomDistanceStart = _touchZoomDistanceEnd = 0;
            _state = STATE.ZOOM;
            break;

          case 5:
            // TOUCH ZOOM
            if (event.touches.length >= 2) {
              var x = (event.touches[0].pageX + event.touches[1].pageX) / 2;
              var y = (event.touches[0].pageY + event.touches[1].pageY) / 2;
              _panEnd.copy(getMouseOnScreen(x, y));
              _panStart.copy(_panEnd);
            }
            _state = STATE.PAN;
            break;

          case 99:
            var x = (event.touches[0].pageX + event.touches[1].pageX) / 2;
            var y = (event.touches[0].pageY + event.touches[1].pageY) / 2;
            _customEnd.copy(getMouseOnScreen(x, y));
            _customStart.copy(_customEnd);
            break;

          default:
            _state = STATE.NONE;
        }
      }

      _this.dispatchEvent(endEvent);
    }

    this.domElement.addEventListener('contextmenu', function(event) {
 event.preventDefault();
}, false);

    this.domElement.addEventListener('mousedown', mousedown, false);

    this.domElement.addEventListener('mousewheel', mousewheel, false);
    this.domElement.addEventListener('DOMMouseScroll', mousewheel, false); // firefox

    this.domElement.addEventListener('touchstart', touchstart, false);
    this.domElement.addEventListener('touchend', touchend, false);
    this.domElement.addEventListener('touchmove', touchmove, false);

    window.addEventListener('keydown', keydown, false);
    window.addEventListener('keyup', keyup, false);

    this.handleResize();

    // force an update at start
    this.update();
  }
}