three.js/examples/js/controls/ArcballControls.js

( function () {

	//trackball state
	const STATE = {
		IDLE: Symbol(),
		ROTATE: Symbol(),
		PAN: Symbol(),
		SCALE: Symbol(),
		FOV: Symbol(),
		FOCUS: Symbol(),
		ZROTATE: Symbol(),
		TOUCH_MULTI: Symbol(),
		ANIMATION_FOCUS: Symbol(),
		ANIMATION_ROTATE: Symbol()
	};
	const INPUT = {
		NONE: Symbol(),
		ONE_FINGER: Symbol(),
		ONE_FINGER_SWITCHED: Symbol(),
		TWO_FINGER: Symbol(),
		MULT_FINGER: Symbol(),
		CURSOR: Symbol()
	};

	//cursor center coordinates
	const _center = {
		x: 0,
		y: 0
	};

	//transformation matrices for gizmos and camera
	const _transformation = {
		camera: new THREE.Matrix4(),
		gizmos: new THREE.Matrix4()
	};

	//events
	const _changeEvent = {
		type: 'change'
	};
	const _startEvent = {
		type: 'start'
	};
	const _endEvent = {
		type: 'end'
	};
	const _raycaster = new THREE.Raycaster();
	const _offset = new THREE.Vector3();
	const _gizmoMatrixStateTemp = new THREE.Matrix4();
	const _cameraMatrixStateTemp = new THREE.Matrix4();
	const _scalePointTemp = new THREE.Vector3();
	/**
 *
 * @param {Camera} camera Virtual camera used in the scene
 * @param {HTMLElement} domElement Renderer's dom element
 * @param {Scene} scene The scene to be rendered
 */
	class ArcballControls extends THREE.EventDispatcher {

		constructor( _camera, domElement, scene = null ) {

			super();
			this.onWindowResize = () => {

				const scale = ( this._gizmos.scale.x + this._gizmos.scale.y + this._gizmos.scale.z ) / 3;
				this._tbRadius = this.calculateTbRadius( this.camera );
				const newRadius = this._tbRadius / scale;
				const curve = new THREE.EllipseCurve( 0, 0, newRadius, newRadius );
				const points = curve.getPoints( this._curvePts );
				const curveGeometry = new THREE.BufferGeometry().setFromPoints( points );
				for ( const gizmo in this._gizmos.children ) {

					this._gizmos.children[ gizmo ].geometry = curveGeometry;

				}

				this.dispatchEvent( _changeEvent );

			};

			this.onContextMenu = event => {

				if ( ! this.enabled ) {

					return;

				}

				for ( let i = 0; i < this.mouseActions.length; i ++ ) {

					if ( this.mouseActions[ i ].mouse == 2 ) {

						//prevent only if button 2 is actually used
						event.preventDefault();
						break;

					}

				}

			};

			this.onPointerCancel = () => {

				this._touchStart.splice( 0, this._touchStart.length );
				this._touchCurrent.splice( 0, this._touchCurrent.length );
				this._input = INPUT.NONE;

			};

			this.onPointerDown = event => {

				if ( event.button == 0 && event.isPrimary ) {

					this._downValid = true;
					this._downEvents.push( event );
					this._downStart = performance.now();

				} else {

					this._downValid = false;

				}

				if ( event.pointerType == 'touch' && this._input != INPUT.CURSOR ) {

					this._touchStart.push( event );
					this._touchCurrent.push( event );
					switch ( this._input ) {

						case INPUT.NONE:
							//singleStart
							this._input = INPUT.ONE_FINGER;
							this.onSinglePanStart( event, 'ROTATE' );
							window.addEventListener( 'pointermove', this.onPointerMove );
							window.addEventListener( 'pointerup', this.onPointerUp );
							break;
						case INPUT.ONE_FINGER:
						case INPUT.ONE_FINGER_SWITCHED:
							//doubleStart
							this._input = INPUT.TWO_FINGER;
							this.onRotateStart();
							this.onPinchStart();
							this.onDoublePanStart();
							break;
						case INPUT.TWO_FINGER:
							//multipleStart
							this._input = INPUT.MULT_FINGER;
							this.onTriplePanStart( event );
							break;

					}

				} else if ( event.pointerType != 'touch' && this._input == INPUT.NONE ) {

					let modifier = null;
					if ( event.ctrlKey || event.metaKey ) {

						modifier = 'CTRL';

					} else if ( event.shiftKey ) {

						modifier = 'SHIFT';

					}

					this._mouseOp = this.getOpFromAction( event.button, modifier );
					if ( this._mouseOp != null ) {

						window.addEventListener( 'pointermove', this.onPointerMove );
						window.addEventListener( 'pointerup', this.onPointerUp );

						//singleStart
						this._input = INPUT.CURSOR;
						this._button = event.button;
						this.onSinglePanStart( event, this._mouseOp );

					}

				}

			};

			this.onPointerMove = event => {

				if ( event.pointerType == 'touch' && this._input != INPUT.CURSOR ) {

					switch ( this._input ) {

						case INPUT.ONE_FINGER:
							//singleMove
							this.updateTouchEvent( event );
							this.onSinglePanMove( event, STATE.ROTATE );
							break;
						case INPUT.ONE_FINGER_SWITCHED:
							const movement = this.calculatePointersDistance( this._touchCurrent[ 0 ], event ) * this._devPxRatio;
							if ( movement >= this._switchSensibility ) {

								//singleMove
								this._input = INPUT.ONE_FINGER;
								this.updateTouchEvent( event );
								this.onSinglePanStart( event, 'ROTATE' );
								break;

							}

							break;
						case INPUT.TWO_FINGER:
							//rotate/pan/pinchMove
							this.updateTouchEvent( event );
							this.onRotateMove();
							this.onPinchMove();
							this.onDoublePanMove();
							break;
						case INPUT.MULT_FINGER:
							//multMove
							this.updateTouchEvent( event );
							this.onTriplePanMove( event );
							break;

					}

				} else if ( event.pointerType != 'touch' && this._input == INPUT.CURSOR ) {

					let modifier = null;
					if ( event.ctrlKey || event.metaKey ) {

						modifier = 'CTRL';

					} else if ( event.shiftKey ) {

						modifier = 'SHIFT';

					}

					const mouseOpState = this.getOpStateFromAction( this._button, modifier );
					if ( mouseOpState != null ) {

						this.onSinglePanMove( event, mouseOpState );

					}

				}

				//checkDistance
				if ( this._downValid ) {

					const movement = this.calculatePointersDistance( this._downEvents[ this._downEvents.length - 1 ], event ) * this._devPxRatio;
					if ( movement > this._movementThreshold ) {

						this._downValid = false;

					}

				}

			};

			this.onPointerUp = event => {

				if ( event.pointerType == 'touch' && this._input != INPUT.CURSOR ) {

					const nTouch = this._touchCurrent.length;
					for ( let i = 0; i < nTouch; i ++ ) {

						if ( this._touchCurrent[ i ].pointerId == event.pointerId ) {

							this._touchCurrent.splice( i, 1 );
							this._touchStart.splice( i, 1 );
							break;

						}

					}

					switch ( this._input ) {

						case INPUT.ONE_FINGER:
						case INPUT.ONE_FINGER_SWITCHED:
							//singleEnd
							window.removeEventListener( 'pointermove', this.onPointerMove );
							window.removeEventListener( 'pointerup', this.onPointerUp );
							this._input = INPUT.NONE;
							this.onSinglePanEnd();
							break;
						case INPUT.TWO_FINGER:
							//doubleEnd
							this.onDoublePanEnd( event );
							this.onPinchEnd( event );
							this.onRotateEnd( event );

							//switching to singleStart
							this._input = INPUT.ONE_FINGER_SWITCHED;
							break;
						case INPUT.MULT_FINGER:
							if ( this._touchCurrent.length == 0 ) {

								window.removeEventListener( 'pointermove', this.onPointerMove );
								window.removeEventListener( 'pointerup', this.onPointerUp );

								//multCancel
								this._input = INPUT.NONE;
								this.onTriplePanEnd();

							}

							break;

					}

				} else if ( event.pointerType != 'touch' && this._input == INPUT.CURSOR ) {

					window.removeEventListener( 'pointermove', this.onPointerMove );
					window.removeEventListener( 'pointerup', this.onPointerUp );
					this._input = INPUT.NONE;
					this.onSinglePanEnd();
					this._button = - 1;

				}

				if ( event.isPrimary ) {

					if ( this._downValid ) {

						const downTime = event.timeStamp - this._downEvents[ this._downEvents.length - 1 ].timeStamp;
						if ( downTime <= this._maxDownTime ) {

							if ( this._nclicks == 0 ) {

								//first valid click detected
								this._nclicks = 1;
								this._clickStart = performance.now();

							} else {

								const clickInterval = event.timeStamp - this._clickStart;
								const movement = this.calculatePointersDistance( this._downEvents[ 1 ], this._downEvents[ 0 ] ) * this._devPxRatio;
								if ( clickInterval <= this._maxInterval && movement <= this._posThreshold ) {

									//second valid click detected
									//fire double tap and reset values
									this._nclicks = 0;
									this._downEvents.splice( 0, this._downEvents.length );
									this.onDoubleTap( event );

								} else {

									//new 'first click'
									this._nclicks = 1;
									this._downEvents.shift();
									this._clickStart = performance.now();

								}

							}

						} else {

							this._downValid = false;
							this._nclicks = 0;
							this._downEvents.splice( 0, this._downEvents.length );

						}

					} else {

						this._nclicks = 0;
						this._downEvents.splice( 0, this._downEvents.length );

					}

				}

			};

			this.onWheel = event => {

				if ( this.enabled && this.enableZoom ) {

					let modifier = null;
					if ( event.ctrlKey || event.metaKey ) {

						modifier = 'CTRL';

					} else if ( event.shiftKey ) {

						modifier = 'SHIFT';

					}

					const mouseOp = this.getOpFromAction( 'WHEEL', modifier );
					if ( mouseOp != null ) {

						event.preventDefault();
						this.dispatchEvent( _startEvent );
						const notchDeltaY = 125; //distance of one notch of mouse wheel
						let sgn = event.deltaY / notchDeltaY;
						let size = 1;
						if ( sgn > 0 ) {

							size = 1 / this.scaleFactor;

						} else if ( sgn < 0 ) {

							size = this.scaleFactor;

						}

						switch ( mouseOp ) {

							case 'ZOOM':
								this.updateTbState( STATE.SCALE, true );
								if ( sgn > 0 ) {

									size = 1 / Math.pow( this.scaleFactor, sgn );

								} else if ( sgn < 0 ) {

									size = Math.pow( this.scaleFactor, - sgn );

								}

								if ( this.cursorZoom && this.enablePan ) {

									let scalePoint;
									if ( this.camera.isOrthographicCamera ) {

										scalePoint = this.unprojectOnTbPlane( this.camera, event.clientX, event.clientY, this.domElement ).applyQuaternion( this.camera.quaternion ).multiplyScalar( 1 / this.camera.zoom ).add( this._gizmos.position );

									} else if ( this.camera.isPerspectiveCamera ) {

										scalePoint = this.unprojectOnTbPlane( this.camera, event.clientX, event.clientY, this.domElement ).applyQuaternion( this.camera.quaternion ).add( this._gizmos.position );

									}

									this.applyTransformMatrix( this.scale( size, scalePoint ) );

								} else {

									this.applyTransformMatrix( this.scale( size, this._gizmos.position ) );

								}

								if ( this._grid != null ) {

									this.disposeGrid();
									this.drawGrid();

								}

								this.updateTbState( STATE.IDLE, false );
								this.dispatchEvent( _changeEvent );
								this.dispatchEvent( _endEvent );
								break;
							case 'FOV':
								if ( this.camera.isPerspectiveCamera ) {

									this.updateTbState( STATE.FOV, true );

									//Vertigo effect

									//	  fov / 2
									//		|\
									//		| \
									//		|  \
									//	x	|	\
									//		| 	 \
									//		| 	  \
									//		| _ _ _\
									//			y

									//check for iOs shift shortcut
									if ( event.deltaX != 0 ) {

										sgn = event.deltaX / notchDeltaY;
										size = 1;
										if ( sgn > 0 ) {

											size = 1 / Math.pow( this.scaleFactor, sgn );

										} else if ( sgn < 0 ) {

											size = Math.pow( this.scaleFactor, - sgn );

										}

									}

									this._v3_1.setFromMatrixPosition( this._cameraMatrixState );
									const x = this._v3_1.distanceTo( this._gizmos.position );
									let xNew = x / size; //distance between camera and gizmos if scale(size, scalepoint) would be performed

									//check min and max distance
									xNew = THREE.MathUtils.clamp( xNew, this.minDistance, this.maxDistance );
									const y = x * Math.tan( THREE.MathUtils.DEG2RAD * this.camera.fov * 0.5 );

									//calculate new fov
									let newFov = THREE.MathUtils.RAD2DEG * ( Math.atan( y / xNew ) * 2 );

									//check min and max fov
									if ( newFov > this.maxFov ) {

										newFov = this.maxFov;

									} else if ( newFov < this.minFov ) {

										newFov = this.minFov;

									}

									const newDistance = y / Math.tan( THREE.MathUtils.DEG2RAD * ( newFov / 2 ) );
									size = x / newDistance;
									this.setFov( newFov );
									this.applyTransformMatrix( this.scale( size, this._gizmos.position, false ) );

								}

								if ( this._grid != null ) {

									this.disposeGrid();
									this.drawGrid();

								}

								this.updateTbState( STATE.IDLE, false );
								this.dispatchEvent( _changeEvent );
								this.dispatchEvent( _endEvent );
								break;

						}

					}

				}

			};

			this.onSinglePanStart = ( event, operation ) => {

				if ( this.enabled ) {

					this.dispatchEvent( _startEvent );
					this.setCenter( event.clientX, event.clientY );
					switch ( operation ) {

						case 'PAN':
							if ( ! this.enablePan ) {

								return;

							}

							if ( this._animationId != - 1 ) {

								cancelAnimationFrame( this._animationId );
								this._animationId = - 1;
								this._timeStart = - 1;
								this.activateGizmos( false );
								this.dispatchEvent( _changeEvent );

							}

							this.updateTbState( STATE.PAN, true );
							this._startCursorPosition.copy( this.unprojectOnTbPlane( this.camera, _center.x, _center.y, this.domElement ) );
							if ( this.enableGrid ) {

								this.drawGrid();
								this.dispatchEvent( _changeEvent );

							}

							break;
						case 'ROTATE':
							if ( ! this.enableRotate ) {

								return;

							}

							if ( this._animationId != - 1 ) {

								cancelAnimationFrame( this._animationId );
								this._animationId = - 1;
								this._timeStart = - 1;

							}

							this.updateTbState( STATE.ROTATE, true );
							this._startCursorPosition.copy( this.unprojectOnTbSurface( this.camera, _center.x, _center.y, this.domElement, this._tbRadius ) );
							this.activateGizmos( true );
							if ( this.enableAnimations ) {

								this._timePrev = this._timeCurrent = performance.now();
								this._angleCurrent = this._anglePrev = 0;
								this._cursorPosPrev.copy( this._startCursorPosition );
								this._cursorPosCurr.copy( this._cursorPosPrev );
								this._wCurr = 0;
								this._wPrev = this._wCurr;

							}

							this.dispatchEvent( _changeEvent );
							break;
						case 'FOV':
							if ( ! this.camera.isPerspectiveCamera || ! this.enableZoom ) {

								return;

							}

							if ( this._animationId != - 1 ) {

								cancelAnimationFrame( this._animationId );
								this._animationId = - 1;
								this._timeStart = - 1;
								this.activateGizmos( false );
								this.dispatchEvent( _changeEvent );

							}

							this.updateTbState( STATE.FOV, true );
							this._startCursorPosition.setY( this.getCursorNDC( _center.x, _center.y, this.domElement ).y * 0.5 );
							this._currentCursorPosition.copy( this._startCursorPosition );
							break;
						case 'ZOOM':
							if ( ! this.enableZoom ) {

								return;

							}

							if ( this._animationId != - 1 ) {

								cancelAnimationFrame( this._animationId );
								this._animationId = - 1;
								this._timeStart = - 1;
								this.activateGizmos( false );
								this.dispatchEvent( _changeEvent );

							}

							this.updateTbState( STATE.SCALE, true );
							this._startCursorPosition.setY( this.getCursorNDC( _center.x, _center.y, this.domElement ).y * 0.5 );
							this._currentCursorPosition.copy( this._startCursorPosition );
							break;

					}

				}

			};

			this.onSinglePanMove = ( event, opState ) => {

				if ( this.enabled ) {

					const restart = opState != this._state;
					this.setCenter( event.clientX, event.clientY );
					switch ( opState ) {

						case STATE.PAN:
							if ( this.enablePan ) {

								if ( restart ) {

									//switch to pan operation

									this.dispatchEvent( _endEvent );
									this.dispatchEvent( _startEvent );
									this.updateTbState( opState, true );
									this._startCursorPosition.copy( this.unprojectOnTbPlane( this.camera, _center.x, _center.y, this.domElement ) );
									if ( this.enableGrid ) {

										this.drawGrid();

									}

									this.activateGizmos( false );

								} else {

									//continue with pan operation
									this._currentCursorPosition.copy( this.unprojectOnTbPlane( this.camera, _center.x, _center.y, this.domElement ) );
									this.applyTransformMatrix( this.pan( this._startCursorPosition, this._currentCursorPosition ) );

								}

							}

							break;
						case STATE.ROTATE:
							if ( this.enableRotate ) {

								if ( restart ) {

									//switch to rotate operation

									this.dispatchEvent( _endEvent );
									this.dispatchEvent( _startEvent );
									this.updateTbState( opState, true );
									this._startCursorPosition.copy( this.unprojectOnTbSurface( this.camera, _center.x, _center.y, this.domElement, this._tbRadius ) );
									if ( this.enableGrid ) {

										this.disposeGrid();

									}

									this.activateGizmos( true );

								} else {

									//continue with rotate operation
									this._currentCursorPosition.copy( this.unprojectOnTbSurface( this.camera, _center.x, _center.y, this.domElement, this._tbRadius ) );
									const distance = this._startCursorPosition.distanceTo( this._currentCursorPosition );
									const angle = this._startCursorPosition.angleTo( this._currentCursorPosition );
									const amount = Math.max( distance / this._tbRadius, angle ); //effective rotation angle

									this.applyTransformMatrix( this.rotate( this.calculateRotationAxis( this._startCursorPosition, this._currentCursorPosition ), amount ) );
									if ( this.enableAnimations ) {

										this._timePrev = this._timeCurrent;
										this._timeCurrent = performance.now();
										this._anglePrev = this._angleCurrent;
										this._angleCurrent = amount;
										this._cursorPosPrev.copy( this._cursorPosCurr );
										this._cursorPosCurr.copy( this._currentCursorPosition );
										this._wPrev = this._wCurr;
										this._wCurr = this.calculateAngularSpeed( this._anglePrev, this._angleCurrent, this._timePrev, this._timeCurrent );

									}

								}

							}

							break;
						case STATE.SCALE:
							if ( this.enableZoom ) {

								if ( restart ) {

									//switch to zoom operation

									this.dispatchEvent( _endEvent );
									this.dispatchEvent( _startEvent );
									this.updateTbState( opState, true );
									this._startCursorPosition.setY( this.getCursorNDC( _center.x, _center.y, this.domElement ).y * 0.5 );
									this._currentCursorPosition.copy( this._startCursorPosition );
									if ( this.enableGrid ) {

										this.disposeGrid();

									}

									this.activateGizmos( false );

								} else {

									//continue with zoom operation
									const screenNotches = 8; //how many wheel notches corresponds to a full screen pan
									this._currentCursorPosition.setY( this.getCursorNDC( _center.x, _center.y, this.domElement ).y * 0.5 );
									const movement = this._currentCursorPosition.y - this._startCursorPosition.y;
									let size = 1;
									if ( movement < 0 ) {

										size = 1 / Math.pow( this.scaleFactor, - movement * screenNotches );

									} else if ( movement > 0 ) {

										size = Math.pow( this.scaleFactor, movement * screenNotches );

									}

									this._v3_1.setFromMatrixPosition( this._gizmoMatrixState );
									this.applyTransformMatrix( this.scale( size, this._v3_1 ) );

								}

							}

							break;
						case STATE.FOV:
							if ( this.enableZoom && this.camera.isPerspectiveCamera ) {

								if ( restart ) {

									//switch to fov operation

									this.dispatchEvent( _endEvent );
									this.dispatchEvent( _startEvent );
									this.updateTbState( opState, true );
									this._startCursorPosition.setY( this.getCursorNDC( _center.x, _center.y, this.domElement ).y * 0.5 );
									this._currentCursorPosition.copy( this._startCursorPosition );
									if ( this.enableGrid ) {

										this.disposeGrid();

									}

									this.activateGizmos( false );

								} else {

									//continue with fov operation
									const screenNotches = 8; //how many wheel notches corresponds to a full screen pan
									this._currentCursorPosition.setY( this.getCursorNDC( _center.x, _center.y, this.domElement ).y * 0.5 );
									const movement = this._currentCursorPosition.y - this._startCursorPosition.y;
									let size = 1;
									if ( movement < 0 ) {

										size = 1 / Math.pow( this.scaleFactor, - movement * screenNotches );

									} else if ( movement > 0 ) {

										size = Math.pow( this.scaleFactor, movement * screenNotches );

									}

									this._v3_1.setFromMatrixPosition( this._cameraMatrixState );
									const x = this._v3_1.distanceTo( this._gizmos.position );
									let xNew = x / size; //distance between camera and gizmos if scale(size, scalepoint) would be performed

									//check min and max distance
									xNew = THREE.MathUtils.clamp( xNew, this.minDistance, this.maxDistance );
									const y = x * Math.tan( THREE.MathUtils.DEG2RAD * this._fovState * 0.5 );

									//calculate new fov
									let newFov = THREE.MathUtils.RAD2DEG * ( Math.atan( y / xNew ) * 2 );

									//check min and max fov
									newFov = THREE.MathUtils.clamp( newFov, this.minFov, this.maxFov );
									const newDistance = y / Math.tan( THREE.MathUtils.DEG2RAD * ( newFov / 2 ) );
									size = x / newDistance;
									this._v3_2.setFromMatrixPosition( this._gizmoMatrixState );
									this.setFov( newFov );
									this.applyTransformMatrix( this.scale( size, this._v3_2, false ) );

									//adjusting distance
									_offset.copy( this._gizmos.position ).sub( this.camera.position ).normalize().multiplyScalar( newDistance / x );
									this._m4_1.makeTranslation( _offset.x, _offset.y, _offset.z );

								}

							}

							break;

					}

					this.dispatchEvent( _changeEvent );

				}

			};

			this.onSinglePanEnd = () => {

				if ( this._state == STATE.ROTATE ) {

					if ( ! this.enableRotate ) {

						return;

					}

					if ( this.enableAnimations ) {

						//perform rotation animation
						const deltaTime = performance.now() - this._timeCurrent;
						if ( deltaTime < 120 ) {

							const w = Math.abs( ( this._wPrev + this._wCurr ) / 2 );
							const self = this;
							this._animationId = window.requestAnimationFrame( function ( t ) {

								self.updateTbState( STATE.ANIMATION_ROTATE, true );
								const rotationAxis = self.calculateRotationAxis( self._cursorPosPrev, self._cursorPosCurr );
								self.onRotationAnim( t, rotationAxis, Math.min( w, self.wMax ) );

							} );

						} else {

							//cursor has been standing still for over 120 ms since last movement
							this.updateTbState( STATE.IDLE, false );
							this.activateGizmos( false );
							this.dispatchEvent( _changeEvent );

						}

					} else {

						this.updateTbState( STATE.IDLE, false );
						this.activateGizmos( false );
						this.dispatchEvent( _changeEvent );

					}

				} else if ( this._state == STATE.PAN || this._state == STATE.IDLE ) {

					this.updateTbState( STATE.IDLE, false );
					if ( this.enableGrid ) {

						this.disposeGrid();

					}

					this.activateGizmos( false );
					this.dispatchEvent( _changeEvent );

				}

				this.dispatchEvent( _endEvent );

			};

			this.onDoubleTap = event => {

				if ( this.enabled && this.enablePan && this.scene != null ) {

					this.dispatchEvent( _startEvent );
					this.setCenter( event.clientX, event.clientY );
					const hitP = this.unprojectOnObj( this.getCursorNDC( _center.x, _center.y, this.domElement ), this.camera );
					if ( hitP != null && this.enableAnimations ) {

						const self = this;
						if ( this._animationId != - 1 ) {

							window.cancelAnimationFrame( this._animationId );

						}

						this._timeStart = - 1;
						this._animationId = window.requestAnimationFrame( function ( t ) {

							self.updateTbState( STATE.ANIMATION_FOCUS, true );
							self.onFocusAnim( t, hitP, self._cameraMatrixState, self._gizmoMatrixState );

						} );

					} else if ( hitP != null && ! this.enableAnimations ) {

						this.updateTbState( STATE.FOCUS, true );
						this.focus( hitP, this.scaleFactor );
						this.updateTbState( STATE.IDLE, false );
						this.dispatchEvent( _changeEvent );

					}

				}

				this.dispatchEvent( _endEvent );

			};

			this.onDoublePanStart = () => {

				if ( this.enabled && this.enablePan ) {

					this.dispatchEvent( _startEvent );
					this.updateTbState( STATE.PAN, true );
					this.setCenter( ( this._touchCurrent[ 0 ].clientX + this._touchCurrent[ 1 ].clientX ) / 2, ( this._touchCurrent[ 0 ].clientY + this._touchCurrent[ 1 ].clientY ) / 2 );
					this._startCursorPosition.copy( this.unprojectOnTbPlane( this.camera, _center.x, _center.y, this.domElement, true ) );
					this._currentCursorPosition.copy( this._startCursorPosition );
					this.activateGizmos( false );

				}

			};

			this.onDoublePanMove = () => {

				if ( this.enabled && this.enablePan ) {

					this.setCenter( ( this._touchCurrent[ 0 ].clientX + this._touchCurrent[ 1 ].clientX ) / 2, ( this._touchCurrent[ 0 ].clientY + this._touchCurrent[ 1 ].clientY ) / 2 );
					if ( this._state != STATE.PAN ) {

						this.updateTbState( STATE.PAN, true );
						this._startCursorPosition.copy( this._currentCursorPosition );

					}

					this._currentCursorPosition.copy( this.unprojectOnTbPlane( this.camera, _center.x, _center.y, this.domElement, true ) );
					this.applyTransformMatrix( this.pan( this._startCursorPosition, this._currentCursorPosition, true ) );
					this.dispatchEvent( _changeEvent );

				}

			};

			this.onDoublePanEnd = () => {

				this.updateTbState( STATE.IDLE, false );
				this.dispatchEvent( _endEvent );

			};

			this.onRotateStart = () => {

				if ( this.enabled && this.enableRotate ) {

					this.dispatchEvent( _startEvent );
					this.updateTbState( STATE.ZROTATE, true );

					//this._startFingerRotation = event.rotation;

					this._startFingerRotation = this.getAngle( this._touchCurrent[ 1 ], this._touchCurrent[ 0 ] ) + this.getAngle( this._touchStart[ 1 ], this._touchStart[ 0 ] );
					this._currentFingerRotation = this._startFingerRotation;
					this.camera.getWorldDirection( this._rotationAxis ); //rotation axis

					if ( ! this.enablePan && ! this.enableZoom ) {

						this.activateGizmos( true );

					}

				}

			};

			this.onRotateMove = () => {

				if ( this.enabled && this.enableRotate ) {

					this.setCenter( ( this._touchCurrent[ 0 ].clientX + this._touchCurrent[ 1 ].clientX ) / 2, ( this._touchCurrent[ 0 ].clientY + this._touchCurrent[ 1 ].clientY ) / 2 );
					let rotationPoint;
					if ( this._state != STATE.ZROTATE ) {

						this.updateTbState( STATE.ZROTATE, true );
						this._startFingerRotation = this._currentFingerRotation;

					}

					//this._currentFingerRotation = event.rotation;
					this._currentFingerRotation = this.getAngle( this._touchCurrent[ 1 ], this._touchCurrent[ 0 ] ) + this.getAngle( this._touchStart[ 1 ], this._touchStart[ 0 ] );
					if ( ! this.enablePan ) {

						rotationPoint = new THREE.Vector3().setFromMatrixPosition( this._gizmoMatrixState );

					} else {

						this._v3_2.setFromMatrixPosition( this._gizmoMatrixState );
						rotationPoint = this.unprojectOnTbPlane( this.camera, _center.x, _center.y, this.domElement ).applyQuaternion( this.camera.quaternion ).multiplyScalar( 1 / this.camera.zoom ).add( this._v3_2 );

					}

					const amount = THREE.MathUtils.DEG2RAD * ( this._startFingerRotation - this._currentFingerRotation );
					this.applyTransformMatrix( this.zRotate( rotationPoint, amount ) );
					this.dispatchEvent( _changeEvent );

				}

			};

			this.onRotateEnd = () => {

				this.updateTbState( STATE.IDLE, false );
				this.activateGizmos( false );
				this.dispatchEvent( _endEvent );

			};

			this.onPinchStart = () => {

				if ( this.enabled && this.enableZoom ) {

					this.dispatchEvent( _startEvent );
					this.updateTbState( STATE.SCALE, true );
					this._startFingerDistance = this.calculatePointersDistance( this._touchCurrent[ 0 ], this._touchCurrent[ 1 ] );
					this._currentFingerDistance = this._startFingerDistance;
					this.activateGizmos( false );

				}

			};

			this.onPinchMove = () => {

				if ( this.enabled && this.enableZoom ) {

					this.setCenter( ( this._touchCurrent[ 0 ].clientX + this._touchCurrent[ 1 ].clientX ) / 2, ( this._touchCurrent[ 0 ].clientY + this._touchCurrent[ 1 ].clientY ) / 2 );
					const minDistance = 12; //minimum distance between fingers (in css pixels)

					if ( this._state != STATE.SCALE ) {

						this._startFingerDistance = this._currentFingerDistance;
						this.updateTbState( STATE.SCALE, true );

					}

					this._currentFingerDistance = Math.max( this.calculatePointersDistance( this._touchCurrent[ 0 ], this._touchCurrent[ 1 ] ), minDistance * this._devPxRatio );
					const amount = this._currentFingerDistance / this._startFingerDistance;
					let scalePoint;
					if ( ! this.enablePan ) {

						scalePoint = this._gizmos.position;

					} else {

						if ( this.camera.isOrthographicCamera ) {

							scalePoint = this.unprojectOnTbPlane( this.camera, _center.x, _center.y, this.domElement ).applyQuaternion( this.camera.quaternion ).multiplyScalar( 1 / this.camera.zoom ).add( this._gizmos.position );

						} else if ( this.camera.isPerspectiveCamera ) {

							scalePoint = this.unprojectOnTbPlane( this.camera, _center.x, _center.y, this.domElement ).applyQuaternion( this.camera.quaternion ).add( this._gizmos.position );

						}

					}

					this.applyTransformMatrix( this.scale( amount, scalePoint ) );
					this.dispatchEvent( _changeEvent );

				}

			};

			this.onPinchEnd = () => {

				this.updateTbState( STATE.IDLE, false );
				this.dispatchEvent( _endEvent );

			};

			this.onTriplePanStart = () => {

				if ( this.enabled && this.enableZoom ) {

					this.dispatchEvent( _startEvent );
					this.updateTbState( STATE.SCALE, true );

					//const center = event.center;
					let clientX = 0;
					let clientY = 0;
					const nFingers = this._touchCurrent.length;
					for ( let i = 0; i < nFingers; i ++ ) {

						clientX += this._touchCurrent[ i ].clientX;
						clientY += this._touchCurrent[ i ].clientY;

					}

					this.setCenter( clientX / nFingers, clientY / nFingers );
					this._startCursorPosition.setY( this.getCursorNDC( _center.x, _center.y, this.domElement ).y * 0.5 );
					this._currentCursorPosition.copy( this._startCursorPosition );

				}

			};

			this.onTriplePanMove = () => {

				if ( this.enabled && this.enableZoom ) {

					//	  fov / 2
					//		|\
					//		| \
					//		|  \
					//	x	|	\
					//		| 	 \
					//		| 	  \
					//		| _ _ _\
					//			y

					//const center = event.center;
					let clientX = 0;
					let clientY = 0;
					const nFingers = this._touchCurrent.length;
					for ( let i = 0; i < nFingers; i ++ ) {

						clientX += this._touchCurrent[ i ].clientX;
						clientY += this._touchCurrent[ i ].clientY;

					}

					this.setCenter( clientX / nFingers, clientY / nFingers );
					const screenNotches = 8; //how many wheel notches corresponds to a full screen pan
					this._currentCursorPosition.setY( this.getCursorNDC( _center.x, _center.y, this.domElement ).y * 0.5 );
					const movement = this._currentCursorPosition.y - this._startCursorPosition.y;
					let size = 1;
					if ( movement < 0 ) {

						size = 1 / Math.pow( this.scaleFactor, - movement * screenNotches );

					} else if ( movement > 0 ) {

						size = Math.pow( this.scaleFactor, movement * screenNotches );

					}

					this._v3_1.setFromMatrixPosition( this._cameraMatrixState );
					const x = this._v3_1.distanceTo( this._gizmos.position );
					let xNew = x / size; //distance between camera and gizmos if scale(size, scalepoint) would be performed

					//check min and max distance
					xNew = THREE.MathUtils.clamp( xNew, this.minDistance, this.maxDistance );
					const y = x * Math.tan( THREE.MathUtils.DEG2RAD * this._fovState * 0.5 );

					//calculate new fov
					let newFov = THREE.MathUtils.RAD2DEG * ( Math.atan( y / xNew ) * 2 );

					//check min and max fov
					newFov = THREE.MathUtils.clamp( newFov, this.minFov, this.maxFov );
					const newDistance = y / Math.tan( THREE.MathUtils.DEG2RAD * ( newFov / 2 ) );
					size = x / newDistance;
					this._v3_2.setFromMatrixPosition( this._gizmoMatrixState );
					this.setFov( newFov );
					this.applyTransformMatrix( this.scale( size, this._v3_2, false ) );

					//adjusting distance
					_offset.copy( this._gizmos.position ).sub( this.camera.position ).normalize().multiplyScalar( newDistance / x );
					this._m4_1.makeTranslation( _offset.x, _offset.y, _offset.z );
					this.dispatchEvent( _changeEvent );

				}

			};

			this.onTriplePanEnd = () => {

				this.updateTbState( STATE.IDLE, false );
				this.dispatchEvent( _endEvent );
				//this.dispatchEvent( _changeEvent );

			};

			this.setCenter = ( clientX, clientY ) => {

				_center.x = clientX;
				_center.y = clientY;

			};

			this.initializeMouseActions = () => {

				this.setMouseAction( 'PAN', 0, 'CTRL' );
				this.setMouseAction( 'PAN', 2 );
				this.setMouseAction( 'ROTATE', 0 );
				this.setMouseAction( 'ZOOM', 'WHEEL' );
				this.setMouseAction( 'ZOOM', 1 );
				this.setMouseAction( 'FOV', 'WHEEL', 'SHIFT' );
				this.setMouseAction( 'FOV', 1, 'SHIFT' );

			};

			this.compareMouseAction = ( action1, action2 ) => {

				if ( action1.operation == action2.operation ) {

					if ( action1.mouse == action2.mouse && action1.key == action2.key ) {

						return true;

					} else {

						return false;

					}

				} else {

					return false;

				}

			};

			this.setMouseAction = ( operation, mouse, key = null ) => {

				const operationInput = [ 'PAN', 'ROTATE', 'ZOOM', 'FOV' ];
				const mouseInput = [ 0, 1, 2, 'WHEEL' ];
				const keyInput = [ 'CTRL', 'SHIFT', null ];
				let state;
				if ( ! operationInput.includes( operation ) || ! mouseInput.includes( mouse ) || ! keyInput.includes( key ) ) {

					//invalid parameters
					return false;

				}

				if ( mouse == 'WHEEL' ) {

					if ( operation != 'ZOOM' && operation != 'FOV' ) {

						//cannot associate 2D operation to 1D input
						return false;

					}

				}

				switch ( operation ) {

					case 'PAN':
						state = STATE.PAN;
						break;
					case 'ROTATE':
						state = STATE.ROTATE;
						break;
					case 'ZOOM':
						state = STATE.SCALE;
						break;
					case 'FOV':
						state = STATE.FOV;
						break;

				}

				const action = {
					operation: operation,
					mouse: mouse,
					key: key,
					state: state
				};
				for ( let i = 0; i < this.mouseActions.length; i ++ ) {

					if ( this.mouseActions[ i ].mouse == action.mouse && this.mouseActions[ i ].key == action.key ) {

						this.mouseActions.splice( i, 1, action );
						return true;

					}

				}

				this.mouseActions.push( action );
				return true;

			};

			this.unsetMouseAction = ( mouse, key = null ) => {

				for ( let i = 0; i < this.mouseActions.length; i ++ ) {

					if ( this.mouseActions[ i ].mouse == mouse && this.mouseActions[ i ].key == key ) {

						this.mouseActions.splice( i, 1 );
						return true;

					}

				}

				return false;

			};

			this.getOpFromAction = ( mouse, key ) => {

				let action;
				for ( let i = 0; i < this.mouseActions.length; i ++ ) {

					action = this.mouseActions[ i ];
					if ( action.mouse == mouse && action.key == key ) {

						return action.operation;

					}

				}

				if ( key != null ) {

					for ( let i = 0; i < this.mouseActions.length; i ++ ) {

						action = this.mouseActions[ i ];
						if ( action.mouse == mouse && action.key == null ) {

							return action.operation;

						}

					}

				}

				return null;

			};

			this.getOpStateFromAction = ( mouse, key ) => {

				let action;
				for ( let i = 0; i < this.mouseActions.length; i ++ ) {

					action = this.mouseActions[ i ];
					if ( action.mouse == mouse && action.key == key ) {

						return action.state;

					}

				}

				if ( key != null ) {

					for ( let i = 0; i < this.mouseActions.length; i ++ ) {

						action = this.mouseActions[ i ];
						if ( action.mouse == mouse && action.key == null ) {

							return action.state;

						}

					}

				}

				return null;

			};

			this.getAngle = ( p1, p2 ) => {

				return Math.atan2( p2.clientY - p1.clientY, p2.clientX - p1.clientX ) * 180 / Math.PI;

			};

			this.updateTouchEvent = event => {

				for ( let i = 0; i < this._touchCurrent.length; i ++ ) {

					if ( this._touchCurrent[ i ].pointerId == event.pointerId ) {

						this._touchCurrent.splice( i, 1, event );
						break;

					}

				}

			};

			this.calculateAngularSpeed = ( p0, p1, t0, t1 ) => {

				const s = p1 - p0;
				const t = ( t1 - t0 ) / 1000;
				if ( t == 0 ) {

					return 0;

				}

				return s / t;

			};

			this.calculatePointersDistance = ( p0, p1 ) => {

				return Math.sqrt( Math.pow( p1.clientX - p0.clientX, 2 ) + Math.pow( p1.clientY - p0.clientY, 2 ) );

			};

			this.calculateRotationAxis = ( vec1, vec2 ) => {

				this._rotationMatrix.extractRotation( this._cameraMatrixState );
				this._quat.setFromRotationMatrix( this._rotationMatrix );
				this._rotationAxis.crossVectors( vec1, vec2 ).applyQuaternion( this._quat );
				return this._rotationAxis.normalize().clone();

			};

			this.calculateTbRadius = camera => {

				const distance = camera.position.distanceTo( this._gizmos.position );
				if ( camera.type == 'PerspectiveCamera' ) {

					const halfFovV = THREE.MathUtils.DEG2RAD * camera.fov * 0.5; //vertical fov/2 in radians
					const halfFovH = Math.atan( camera.aspect * Math.tan( halfFovV ) ); //horizontal fov/2 in radians
					return Math.tan( Math.min( halfFovV, halfFovH ) ) * distance * this.radiusFactor;

				} else if ( camera.type == 'OrthographicCamera' ) {

					return Math.min( camera.top, camera.right ) * this.radiusFactor;

				}

			};

			this.focus = ( point, size, amount = 1 ) => {

				//move center of camera (along with gizmos) towards point of interest
				_offset.copy( point ).sub( this._gizmos.position ).multiplyScalar( amount );
				this._translationMatrix.makeTranslation( _offset.x, _offset.y, _offset.z );
				_gizmoMatrixStateTemp.copy( this._gizmoMatrixState );
				this._gizmoMatrixState.premultiply( this._translationMatrix );
				this._gizmoMatrixState.decompose( this._gizmos.position, this._gizmos.quaternion, this._gizmos.scale );
				_cameraMatrixStateTemp.copy( this._cameraMatrixState );
				this._cameraMatrixState.premultiply( this._translationMatrix );
				this._cameraMatrixState.decompose( this.camera.position, this.camera.quaternion, this.camera.scale );

				//apply zoom
				if ( this.enableZoom ) {

					this.applyTransformMatrix( this.scale( size, this._gizmos.position ) );

				}

				this._gizmoMatrixState.copy( _gizmoMatrixStateTemp );
				this._cameraMatrixState.copy( _cameraMatrixStateTemp );

			};

			this.drawGrid = () => {

				if ( this.scene != null ) {

					const color = 0x888888;
					const multiplier = 3;
					let size, divisions, maxLength, tick;
					if ( this.camera.isOrthographicCamera ) {

						const width = this.camera.right - this.camera.left;
						const height = this.camera.bottom - this.camera.top;
						maxLength = Math.max( width, height );
						tick = maxLength / 20;
						size = maxLength / this.camera.zoom * multiplier;
						divisions = size / tick * this.camera.zoom;

					} else if ( this.camera.isPerspectiveCamera ) {

						const distance = this.camera.position.distanceTo( this._gizmos.position );
						const halfFovV = THREE.MathUtils.DEG2RAD * this.camera.fov * 0.5;
						const halfFovH = Math.atan( this.camera.aspect * Math.tan( halfFovV ) );
						maxLength = Math.tan( Math.max( halfFovV, halfFovH ) ) * distance * 2;
						tick = maxLength / 20;
						size = maxLength * multiplier;
						divisions = size / tick;

					}

					if ( this._grid == null ) {

						this._grid = new THREE.GridHelper( size, divisions, color, color );
						this._grid.position.copy( this._gizmos.position );
						this._gridPosition.copy( this._grid.position );
						this._grid.quaternion.copy( this.camera.quaternion );
						this._grid.rotateX( Math.PI * 0.5 );
						this.scene.add( this._grid );

					}

				}

			};

			this.dispose = () => {

				if ( this._animationId != - 1 ) {

					window.cancelAnimationFrame( this._animationId );

				}

				this.domElement.removeEventListener( 'pointerdown', this.onPointerDown );
				this.domElement.removeEventListener( 'pointercancel', this.onPointerCancel );
				this.domElement.removeEventListener( 'wheel', this.onWheel );
				this.domElement.removeEventListener( 'contextmenu', this.onContextMenu );
				window.removeEventListener( 'pointermove', this.onPointerMove );
				window.removeEventListener( 'pointerup', this.onPointerUp );
				window.removeEventListener( 'resize', this.onWindowResize );
				if ( this.scene !== null ) this.scene.remove( this._gizmos );
				this.disposeGrid();

			};

			this.disposeGrid = () => {

				if ( this._grid != null && this.scene != null ) {

					this.scene.remove( this._grid );
					this._grid = null;

				}

			};

			this.easeOutCubic = t => {

				return 1 - Math.pow( 1 - t, 3 );

			};

			this.activateGizmos = isActive => {

				const gizmoX = this._gizmos.children[ 0 ];
				const gizmoY = this._gizmos.children[ 1 ];
				const gizmoZ = this._gizmos.children[ 2 ];
				if ( isActive ) {

					gizmoX.material.setValues( {
						opacity: 1
					} );
					gizmoY.material.setValues( {
						opacity: 1
					} );
					gizmoZ.material.setValues( {
						opacity: 1
					} );

				} else {

					gizmoX.material.setValues( {
						opacity: 0.6
					} );
					gizmoY.material.setValues( {
						opacity: 0.6
					} );
					gizmoZ.material.setValues( {
						opacity: 0.6
					} );

				}

			};

			this.getCursorNDC = ( cursorX, cursorY, canvas ) => {

				const canvasRect = canvas.getBoundingClientRect();
				this._v2_1.setX( ( cursorX - canvasRect.left ) / canvasRect.width * 2 - 1 );
				this._v2_1.setY( ( canvasRect.bottom - cursorY ) / canvasRect.height * 2 - 1 );
				return this._v2_1.clone();

			};

			this.getCursorPosition = ( cursorX, cursorY, canvas ) => {

				this._v2_1.copy( this.getCursorNDC( cursorX, cursorY, canvas ) );
				this._v2_1.x *= ( this.camera.right - this.camera.left ) * 0.5;
				this._v2_1.y *= ( this.camera.top - this.camera.bottom ) * 0.5;
				return this._v2_1.clone();

			};

			this.setCamera = camera => {

				camera.lookAt( this.target );
				camera.updateMatrix();

				//setting state
				if ( camera.type == 'PerspectiveCamera' ) {

					this._fov0 = camera.fov;
					this._fovState = camera.fov;

				}

				this._cameraMatrixState0.copy( camera.matrix );
				this._cameraMatrixState.copy( this._cameraMatrixState0 );
				this._cameraProjectionState.copy( camera.projectionMatrix );
				this._zoom0 = camera.zoom;
				this._zoomState = this._zoom0;
				this._initialNear = camera.near;
				this._nearPos0 = camera.position.distanceTo( this.target ) - camera.near;
				this._nearPos = this._initialNear;
				this._initialFar = camera.far;
				this._farPos0 = camera.position.distanceTo( this.target ) - camera.far;
				this._farPos = this._initialFar;
				this._up0.copy( camera.up );
				this._upState.copy( camera.up );
				this.camera = camera;
				this.camera.updateProjectionMatrix();

				//making gizmos
				this._tbRadius = this.calculateTbRadius( camera );
				this.makeGizmos( this.target, this._tbRadius );

			};

			this.makeGizmos = ( tbCenter, tbRadius ) => {

				const curve = new THREE.EllipseCurve( 0, 0, tbRadius, tbRadius );
				const points = curve.getPoints( this._curvePts );

				//geometry
				const curveGeometry = new THREE.BufferGeometry().setFromPoints( points );

				//material
				const curveMaterialX = new THREE.LineBasicMaterial( {
					color: 0xff8080,
					fog: false,
					transparent: true,
					opacity: 0.6
				} );
				const curveMaterialY = new THREE.LineBasicMaterial( {
					color: 0x80ff80,
					fog: false,
					transparent: true,
					opacity: 0.6
				} );
				const curveMaterialZ = new THREE.LineBasicMaterial( {
					color: 0x8080ff,
					fog: false,
					transparent: true,
					opacity: 0.6
				} );

				//line
				const gizmoX = new THREE.Line( curveGeometry, curveMaterialX );
				const gizmoY = new THREE.Line( curveGeometry, curveMaterialY );
				const gizmoZ = new THREE.Line( curveGeometry, curveMaterialZ );
				const rotation = Math.PI * 0.5;
				gizmoX.rotation.x = rotation;
				gizmoY.rotation.y = rotation;

				//setting state
				this._gizmoMatrixState0.identity().setPosition( tbCenter );
				this._gizmoMatrixState.copy( this._gizmoMatrixState0 );
				if ( this.camera.zoom !== 1 ) {

					//adapt gizmos size to camera zoom
					const size = 1 / this.camera.zoom;
					this._scaleMatrix.makeScale( size, size, size );
					this._translationMatrix.makeTranslation( - tbCenter.x, - tbCenter.y, - tbCenter.z );
					this._gizmoMatrixState.premultiply( this._translationMatrix ).premultiply( this._scaleMatrix );
					this._translationMatrix.makeTranslation( tbCenter.x, tbCenter.y, tbCenter.z );
					this._gizmoMatrixState.premultiply( this._translationMatrix );

				}

				this._gizmoMatrixState.decompose( this._gizmos.position, this._gizmos.quaternion, this._gizmos.scale );

				//

				this._gizmos.traverse( function ( object ) {

					if ( object.isLine ) {

						object.geometry.dispose();
						object.material.dispose();

					}

				} );
				this._gizmos.clear();

				//

				this._gizmos.add( gizmoX );
				this._gizmos.add( gizmoY );
				this._gizmos.add( gizmoZ );

			};

			this.onFocusAnim = ( time, point, cameraMatrix, gizmoMatrix ) => {

				if ( this._timeStart == - 1 ) {

					//animation start
					this._timeStart = time;

				}

				if ( this._state == STATE.ANIMATION_FOCUS ) {

					const deltaTime = time - this._timeStart;
					const animTime = deltaTime / this.focusAnimationTime;
					this._gizmoMatrixState.copy( gizmoMatrix );
					if ( animTime >= 1 ) {

						//animation end

						this._gizmoMatrixState.decompose( this._gizmos.position, this._gizmos.quaternion, this._gizmos.scale );
						this.focus( point, this.scaleFactor );
						this._timeStart = - 1;
						this.updateTbState( STATE.IDLE, false );
						this.activateGizmos( false );
						this.dispatchEvent( _changeEvent );

					} else {

						const amount = this.easeOutCubic( animTime );
						const size = 1 - amount + this.scaleFactor * amount;
						this._gizmoMatrixState.decompose( this._gizmos.position, this._gizmos.quaternion, this._gizmos.scale );
						this.focus( point, size, amount );
						this.dispatchEvent( _changeEvent );
						const self = this;
						this._animationId = window.requestAnimationFrame( function ( t ) {

							self.onFocusAnim( t, point, cameraMatrix, gizmoMatrix.clone() );

						} );

					}

				} else {

					//interrupt animation

					this._animationId = - 1;
					this._timeStart = - 1;

				}

			};

			this.onRotationAnim = ( time, rotationAxis, w0 ) => {

				if ( this._timeStart == - 1 ) {

					//animation start
					this._anglePrev = 0;
					this._angleCurrent = 0;
					this._timeStart = time;

				}

				if ( this._state == STATE.ANIMATION_ROTATE ) {

					//w = w0 + alpha * t
					const deltaTime = ( time - this._timeStart ) / 1000;
					const w = w0 + - this.dampingFactor * deltaTime;
					if ( w > 0 ) {

						//tetha = 0.5 * alpha * t^2 + w0 * t + tetha0
						this._angleCurrent = 0.5 * - this.dampingFactor * Math.pow( deltaTime, 2 ) + w0 * deltaTime + 0;
						this.applyTransformMatrix( this.rotate( rotationAxis, this._angleCurrent ) );
						this.dispatchEvent( _changeEvent );
						const self = this;
						this._animationId = window.requestAnimationFrame( function ( t ) {

							self.onRotationAnim( t, rotationAxis, w0 );

						} );

					} else {

						this._animationId = - 1;
						this._timeStart = - 1;
						this.updateTbState( STATE.IDLE, false );
						this.activateGizmos( false );
						this.dispatchEvent( _changeEvent );

					}

				} else {

					//interrupt animation

					this._animationId = - 1;
					this._timeStart = - 1;
					if ( this._state != STATE.ROTATE ) {

						this.activateGizmos( false );
						this.dispatchEvent( _changeEvent );

					}

				}

			};

			this.pan = ( p0, p1, adjust = false ) => {

				const movement = p0.clone().sub( p1 );
				if ( this.camera.isOrthographicCamera ) {

					//adjust movement amount
					movement.multiplyScalar( 1 / this.camera.zoom );

				} else if ( this.camera.isPerspectiveCamera && adjust ) {

					//adjust movement amount
					this._v3_1.setFromMatrixPosition( this._cameraMatrixState0 ); //camera's initial position
					this._v3_2.setFromMatrixPosition( this._gizmoMatrixState0 ); //gizmo's initial position
					const distanceFactor = this._v3_1.distanceTo( this._v3_2 ) / this.camera.position.distanceTo( this._gizmos.position );
					movement.multiplyScalar( 1 / distanceFactor );

				}

				this._v3_1.set( movement.x, movement.y, 0 ).applyQuaternion( this.camera.quaternion );
				this._m4_1.makeTranslation( this._v3_1.x, this._v3_1.y, this._v3_1.z );
				this.setTransformationMatrices( this._m4_1, this._m4_1 );
				return _transformation;

			};

			this.reset = () => {

				this.camera.zoom = this._zoom0;
				if ( this.camera.isPerspectiveCamera ) {

					this.camera.fov = this._fov0;

				}

				this.camera.near = this._nearPos;
				this.camera.far = this._farPos;
				this._cameraMatrixState.copy( this._cameraMatrixState0 );
				this._cameraMatrixState.decompose( this.camera.position, this.camera.quaternion, this.camera.scale );
				this.camera.up.copy( this._up0 );
				this.camera.updateMatrix();
				this.camera.updateProjectionMatrix();
				this._gizmoMatrixState.copy( this._gizmoMatrixState0 );
				this._gizmoMatrixState0.decompose( this._gizmos.position, this._gizmos.quaternion, this._gizmos.scale );
				this._gizmos.updateMatrix();
				this._tbRadius = this.calculateTbRadius( this.camera );
				this.makeGizmos( this._gizmos.position, this._tbRadius );
				this.camera.lookAt( this._gizmos.position );
				this.updateTbState( STATE.IDLE, false );
				this.dispatchEvent( _changeEvent );

			};

			this.rotate = ( axis, angle ) => {

				const point = this._gizmos.position; //rotation center
				this._translationMatrix.makeTranslation( - point.x, - point.y, - point.z );
				this._rotationMatrix.makeRotationAxis( axis, - angle );

				//rotate camera
				this._m4_1.makeTranslation( point.x, point.y, point.z );
				this._m4_1.multiply( this._rotationMatrix );
				this._m4_1.multiply( this._translationMatrix );
				this.setTransformationMatrices( this._m4_1 );
				return _transformation;

			};

			this.copyState = () => {

				let state;
				if ( this.camera.isOrthographicCamera ) {

					state = JSON.stringify( {
						arcballState: {
							cameraFar: this.camera.far,
							cameraMatrix: this.camera.matrix,
							cameraNear: this.camera.near,
							cameraUp: this.camera.up,
							cameraZoom: this.camera.zoom,
							gizmoMatrix: this._gizmos.matrix
						}
					} );

				} else if ( this.camera.isPerspectiveCamera ) {

					state = JSON.stringify( {
						arcballState: {
							cameraFar: this.camera.far,
							cameraFov: this.camera.fov,
							cameraMatrix: this.camera.matrix,
							cameraNear: this.camera.near,
							cameraUp: this.camera.up,
							cameraZoom: this.camera.zoom,
							gizmoMatrix: this._gizmos.matrix
						}
					} );

				}

				navigator.clipboard.writeText( state );

			};

			this.pasteState = () => {

				const self = this;
				navigator.clipboard.readText().then( function resolved( value ) {

					self.setStateFromJSON( value );

				} );

			};

			this.saveState = () => {

				this._cameraMatrixState0.copy( this.camera.matrix );
				this._gizmoMatrixState0.copy( this._gizmos.matrix );
				this._nearPos = this.camera.near;
				this._farPos = this.camera.far;
				this._zoom0 = this.camera.zoom;
				this._up0.copy( this.camera.up );
				if ( this.camera.isPerspectiveCamera ) {

					this._fov0 = this.camera.fov;

				}

			};

			this.scale = ( size, point, scaleGizmos = true ) => {

				_scalePointTemp.copy( point );
				let sizeInverse = 1 / size;
				if ( this.camera.isOrthographicCamera ) {

					//camera zoom
					this.camera.zoom = this._zoomState;
					this.camera.zoom *= size;

					//check min and max zoom
					if ( this.camera.zoom > this.maxZoom ) {

						this.camera.zoom = this.maxZoom;
						sizeInverse = this._zoomState / this.maxZoom;

					} else if ( this.camera.zoom < this.minZoom ) {

						this.camera.zoom = this.minZoom;
						sizeInverse = this._zoomState / this.minZoom;

					}

					this.camera.updateProjectionMatrix();
					this._v3_1.setFromMatrixPosition( this._gizmoMatrixState ); //gizmos position

					//scale gizmos so they appear in the same spot having the same dimension
					this._scaleMatrix.makeScale( sizeInverse, sizeInverse, sizeInverse );
					this._translationMatrix.makeTranslation( - this._v3_1.x, - this._v3_1.y, - this._v3_1.z );
					this._m4_2.makeTranslation( this._v3_1.x, this._v3_1.y, this._v3_1.z ).multiply( this._scaleMatrix );
					this._m4_2.multiply( this._translationMatrix );

					//move camera and gizmos to obtain pinch effect
					_scalePointTemp.sub( this._v3_1 );
					const amount = _scalePointTemp.clone().multiplyScalar( sizeInverse );
					_scalePointTemp.sub( amount );
					this._m4_1.makeTranslation( _scalePointTemp.x, _scalePointTemp.y, _scalePointTemp.z );
					this._m4_2.premultiply( this._m4_1 );
					this.setTransformationMatrices( this._m4_1, this._m4_2 );
					return _transformation;

				} else if ( this.camera.isPerspectiveCamera ) {

					this._v3_1.setFromMatrixPosition( this._cameraMatrixState );
					this._v3_2.setFromMatrixPosition( this._gizmoMatrixState );

					//move camera
					let distance = this._v3_1.distanceTo( _scalePointTemp );
					let amount = distance - distance * sizeInverse;

					//check min and max distance
					const newDistance = distance - amount;
					if ( newDistance < this.minDistance ) {

						sizeInverse = this.minDistance / distance;
						amount = distance - distance * sizeInverse;

					} else if ( newDistance > this.maxDistance ) {

						sizeInverse = this.maxDistance / distance;
						amount = distance - distance * sizeInverse;

					}

					_offset.copy( _scalePointTemp ).sub( this._v3_1 ).normalize().multiplyScalar( amount );
					this._m4_1.makeTranslation( _offset.x, _offset.y, _offset.z );
					if ( scaleGizmos ) {

						//scale gizmos so they appear in the same spot having the same dimension
						const pos = this._v3_2;
						distance = pos.distanceTo( _scalePointTemp );
						amount = distance - distance * sizeInverse;
						_offset.copy( _scalePointTemp ).sub( this._v3_2 ).normalize().multiplyScalar( amount );
						this._translationMatrix.makeTranslation( pos.x, pos.y, pos.z );
						this._scaleMatrix.makeScale( sizeInverse, sizeInverse, sizeInverse );
						this._m4_2.makeTranslation( _offset.x, _offset.y, _offset.z ).multiply( this._translationMatrix );
						this._m4_2.multiply( this._scaleMatrix );
						this._translationMatrix.makeTranslation( - pos.x, - pos.y, - pos.z );
						this._m4_2.multiply( this._translationMatrix );
						this.setTransformationMatrices( this._m4_1, this._m4_2 );

					} else {

						this.setTransformationMatrices( this._m4_1 );

					}

					return _transformation;

				}

			};

			this.setFov = value => {

				if ( this.camera.isPerspectiveCamera ) {

					this.camera.fov = THREE.MathUtils.clamp( value, this.minFov, this.maxFov );
					this.camera.updateProjectionMatrix();

				}

			};

			this.zRotate = ( point, angle ) => {

				this._rotationMatrix.makeRotationAxis( this._rotationAxis, angle );
				this._translationMatrix.makeTranslation( - point.x, - point.y, - point.z );
				this._m4_1.makeTranslation( point.x, point.y, point.z );
				this._m4_1.multiply( this._rotationMatrix );
				this._m4_1.multiply( this._translationMatrix );
				this._v3_1.setFromMatrixPosition( this._gizmoMatrixState ).sub( point ); //vector from rotation center to gizmos position
				this._v3_2.copy( this._v3_1 ).applyAxisAngle( this._rotationAxis, angle ); //apply rotation
				this._v3_2.sub( this._v3_1 );
				this._m4_2.makeTranslation( this._v3_2.x, this._v3_2.y, this._v3_2.z );
				this.setTransformationMatrices( this._m4_1, this._m4_2 );
				return _transformation;

			};

			this.unprojectOnObj = ( cursor, camera ) => {

				const raycaster = this.getRaycaster();
				raycaster.near = camera.near;
				raycaster.far = camera.far;
				raycaster.setFromCamera( cursor, camera );
				const intersect = raycaster.intersectObjects( this.scene.children, true );
				for ( let i = 0; i < intersect.length; i ++ ) {

					if ( intersect[ i ].object.uuid != this._gizmos.uuid && intersect[ i ].face != null ) {

						return intersect[ i ].point.clone();

					}

				}

				return null;

			};

			this.unprojectOnTbSurface = ( camera, cursorX, cursorY, canvas, tbRadius ) => {

				if ( camera.type == 'OrthographicCamera' ) {

					this._v2_1.copy( this.getCursorPosition( cursorX, cursorY, canvas ) );
					this._v3_1.set( this._v2_1.x, this._v2_1.y, 0 );
					const x2 = Math.pow( this._v2_1.x, 2 );
					const y2 = Math.pow( this._v2_1.y, 2 );
					const r2 = Math.pow( this._tbRadius, 2 );
					if ( x2 + y2 <= r2 * 0.5 ) {

						//intersection with sphere
						this._v3_1.setZ( Math.sqrt( r2 - ( x2 + y2 ) ) );

					} else {

						//intersection with hyperboloid
						this._v3_1.setZ( r2 * 0.5 / Math.sqrt( x2 + y2 ) );

					}

					return this._v3_1;

				} else if ( camera.type == 'PerspectiveCamera' ) {

					//unproject cursor on the near plane
					this._v2_1.copy( this.getCursorNDC( cursorX, cursorY, canvas ) );
					this._v3_1.set( this._v2_1.x, this._v2_1.y, - 1 );
					this._v3_1.applyMatrix4( camera.projectionMatrixInverse );
					const rayDir = this._v3_1.clone().normalize(); //unprojected ray direction
					const cameraGizmoDistance = camera.position.distanceTo( this._gizmos.position );
					const radius2 = Math.pow( tbRadius, 2 );

					//	  camera
					//		|\
					//		| \
					//		|  \
					//	h	|	\
					//		| 	 \
					//		| 	  \
					//	_ _ | _ _ _\ _ _  near plane
					//			l

					const h = this._v3_1.z;
					const l = Math.sqrt( Math.pow( this._v3_1.x, 2 ) + Math.pow( this._v3_1.y, 2 ) );
					if ( l == 0 ) {

						//ray aligned with camera
						rayDir.set( this._v3_1.x, this._v3_1.y, tbRadius );
						return rayDir;

					}

					const m = h / l;
					const q = cameraGizmoDistance;

					/*
         * calculate intersection point between unprojected ray and trackball surface
         *|y = m * x + q
         *|x^2 + y^2 = r^2
         *
         * (m^2 + 1) * x^2 + (2 * m * q) * x + q^2 - r^2 = 0
         */
					let a = Math.pow( m, 2 ) + 1;
					let b = 2 * m * q;
					let c = Math.pow( q, 2 ) - radius2;
					let delta = Math.pow( b, 2 ) - 4 * a * c;
					if ( delta >= 0 ) {

						//intersection with sphere
						this._v2_1.setX( ( - b - Math.sqrt( delta ) ) / ( 2 * a ) );
						this._v2_1.setY( m * this._v2_1.x + q );
						const angle = THREE.MathUtils.RAD2DEG * this._v2_1.angle();
						if ( angle >= 45 ) {

							//if angle between intersection point and X' axis is >= 45°, return that point
							//otherwise, calculate intersection point with hyperboloid

							const rayLength = Math.sqrt( Math.pow( this._v2_1.x, 2 ) + Math.pow( cameraGizmoDistance - this._v2_1.y, 2 ) );
							rayDir.multiplyScalar( rayLength );
							rayDir.z += cameraGizmoDistance;
							return rayDir;

						}

					}

					//intersection with hyperboloid
					/*
         *|y = m * x + q
         *|y = (1 / x) * (r^2 / 2)
         *
         * m * x^2 + q * x - r^2 / 2 = 0
         */

					a = m;
					b = q;
					c = - radius2 * 0.5;
					delta = Math.pow( b, 2 ) - 4 * a * c;
					this._v2_1.setX( ( - b - Math.sqrt( delta ) ) / ( 2 * a ) );
					this._v2_1.setY( m * this._v2_1.x + q );
					const rayLength = Math.sqrt( Math.pow( this._v2_1.x, 2 ) + Math.pow( cameraGizmoDistance - this._v2_1.y, 2 ) );
					rayDir.multiplyScalar( rayLength );
					rayDir.z += cameraGizmoDistance;
					return rayDir;

				}

			};

			this.unprojectOnTbPlane = ( camera, cursorX, cursorY, canvas, initialDistance = false ) => {

				if ( camera.type == 'OrthographicCamera' ) {

					this._v2_1.copy( this.getCursorPosition( cursorX, cursorY, canvas ) );
					this._v3_1.set( this._v2_1.x, this._v2_1.y, 0 );
					return this._v3_1.clone();

				} else if ( camera.type == 'PerspectiveCamera' ) {

					this._v2_1.copy( this.getCursorNDC( cursorX, cursorY, canvas ) );

					//unproject cursor on the near plane
					this._v3_1.set( this._v2_1.x, this._v2_1.y, - 1 );
					this._v3_1.applyMatrix4( camera.projectionMatrixInverse );
					const rayDir = this._v3_1.clone().normalize(); //unprojected ray direction

					//	  camera
					//		|\
					//		| \
					//		|  \
					//	h	|	\
					//		| 	 \
					//		| 	  \
					//	_ _ | _ _ _\ _ _  near plane
					//			l

					const h = this._v3_1.z;
					const l = Math.sqrt( Math.pow( this._v3_1.x, 2 ) + Math.pow( this._v3_1.y, 2 ) );
					let cameraGizmoDistance;
					if ( initialDistance ) {

						cameraGizmoDistance = this._v3_1.setFromMatrixPosition( this._cameraMatrixState0 ).distanceTo( this._v3_2.setFromMatrixPosition( this._gizmoMatrixState0 ) );

					} else {

						cameraGizmoDistance = camera.position.distanceTo( this._gizmos.position );

					}

					/*
         * calculate intersection point between unprojected ray and the plane
         *|y = mx + q
         *|y = 0
         *
         * x = -q/m
        */
					if ( l == 0 ) {

						//ray aligned with camera
						rayDir.set( 0, 0, 0 );
						return rayDir;

					}

					const m = h / l;
					const q = cameraGizmoDistance;
					const x = - q / m;
					const rayLength = Math.sqrt( Math.pow( q, 2 ) + Math.pow( x, 2 ) );
					rayDir.multiplyScalar( rayLength );
					rayDir.z = 0;
					return rayDir;

				}

			};

			this.updateMatrixState = () => {

				//update camera and gizmos state
				this._cameraMatrixState.copy( this.camera.matrix );
				this._gizmoMatrixState.copy( this._gizmos.matrix );
				if ( this.camera.isOrthographicCamera ) {

					this._cameraProjectionState.copy( this.camera.projectionMatrix );
					this.camera.updateProjectionMatrix();
					this._zoomState = this.camera.zoom;

				} else if ( this.camera.isPerspectiveCamera ) {

					this._fovState = this.camera.fov;

				}

			};

			this.updateTbState = ( newState, updateMatrices ) => {

				this._state = newState;
				if ( updateMatrices ) {

					this.updateMatrixState();

				}

			};

			this.update = () => {

				const EPS = 0.000001;
				if ( this.target.equals( this._currentTarget ) === false ) {

					this._gizmos.position.copy( this.target ); //for correct radius calculation
					this._tbRadius = this.calculateTbRadius( this.camera );
					this.makeGizmos( this.target, this._tbRadius );
					this._currentTarget.copy( this.target );

				}

				//check min/max parameters
				if ( this.camera.isOrthographicCamera ) {

					//check zoom
					if ( this.camera.zoom > this.maxZoom || this.camera.zoom < this.minZoom ) {

						const newZoom = THREE.MathUtils.clamp( this.camera.zoom, this.minZoom, this.maxZoom );
						this.applyTransformMatrix( this.scale( newZoom / this.camera.zoom, this._gizmos.position, true ) );

					}

				} else if ( this.camera.isPerspectiveCamera ) {

					//check distance
					const distance = this.camera.position.distanceTo( this._gizmos.position );
					if ( distance > this.maxDistance + EPS || distance < this.minDistance - EPS ) {

						const newDistance = THREE.MathUtils.clamp( distance, this.minDistance, this.maxDistance );
						this.applyTransformMatrix( this.scale( newDistance / distance, this._gizmos.position ) );
						this.updateMatrixState();

					}

					//check fov
					if ( this.camera.fov < this.minFov || this.camera.fov > this.maxFov ) {

						this.camera.fov = THREE.MathUtils.clamp( this.camera.fov, this.minFov, this.maxFov );
						this.camera.updateProjectionMatrix();

					}

					const oldRadius = this._tbRadius;
					this._tbRadius = this.calculateTbRadius( this.camera );
					if ( oldRadius < this._tbRadius - EPS || oldRadius > this._tbRadius + EPS ) {

						const scale = ( this._gizmos.scale.x + this._gizmos.scale.y + this._gizmos.scale.z ) / 3;
						const newRadius = this._tbRadius / scale;
						const curve = new THREE.EllipseCurve( 0, 0, newRadius, newRadius );
						const points = curve.getPoints( this._curvePts );
						const curveGeometry = new THREE.BufferGeometry().setFromPoints( points );
						for ( const gizmo in this._gizmos.children ) {

							this._gizmos.children[ gizmo ].geometry = curveGeometry;

						}

					}

				}

				this.camera.lookAt( this._gizmos.position );

			};

			this.setStateFromJSON = json => {

				const state = JSON.parse( json );
				if ( state.arcballState != undefined ) {

					this._cameraMatrixState.fromArray( state.arcballState.cameraMatrix.elements );
					this._cameraMatrixState.decompose( this.camera.position, this.camera.quaternion, this.camera.scale );
					this.camera.up.copy( state.arcballState.cameraUp );
					this.camera.near = state.arcballState.cameraNear;
					this.camera.far = state.arcballState.cameraFar;
					this.camera.zoom = state.arcballState.cameraZoom;
					if ( this.camera.isPerspectiveCamera ) {

						this.camera.fov = state.arcballState.cameraFov;

					}

					this._gizmoMatrixState.fromArray( state.arcballState.gizmoMatrix.elements );
					this._gizmoMatrixState.decompose( this._gizmos.position, this._gizmos.quaternion, this._gizmos.scale );
					this.camera.updateMatrix();
					this.camera.updateProjectionMatrix();
					this._gizmos.updateMatrix();
					this._tbRadius = this.calculateTbRadius( this.camera );
					const gizmoTmp = new THREE.Matrix4().copy( this._gizmoMatrixState0 );
					this.makeGizmos( this._gizmos.position, this._tbRadius );
					this._gizmoMatrixState0.copy( gizmoTmp );
					this.camera.lookAt( this._gizmos.position );
					this.updateTbState( STATE.IDLE, false );
					this.dispatchEvent( _changeEvent );

				}

			};

			this.camera = null;
			this.domElement = domElement;
			this.scene = scene;
			this.target = new THREE.Vector3();
			this._currentTarget = new THREE.Vector3();
			this.radiusFactor = 0.67;
			this.mouseActions = [];
			this._mouseOp = null;

			//global vectors and matrices that are used in some operations to avoid creating new objects every time (e.g. every time cursor moves)
			this._v2_1 = new THREE.Vector2();
			this._v3_1 = new THREE.Vector3();
			this._v3_2 = new THREE.Vector3();
			this._m4_1 = new THREE.Matrix4();
			this._m4_2 = new THREE.Matrix4();
			this._quat = new THREE.Quaternion();

			//transformation matrices
			this._translationMatrix = new THREE.Matrix4(); //matrix for translation operation
			this._rotationMatrix = new THREE.Matrix4(); //matrix for rotation operation
			this._scaleMatrix = new THREE.Matrix4(); //matrix for scaling operation

			this._rotationAxis = new THREE.Vector3(); //axis for rotate operation

			//camera state
			this._cameraMatrixState = new THREE.Matrix4();
			this._cameraProjectionState = new THREE.Matrix4();
			this._fovState = 1;
			this._upState = new THREE.Vector3();
			this._zoomState = 1;
			this._nearPos = 0;
			this._farPos = 0;
			this._gizmoMatrixState = new THREE.Matrix4();

			//initial values
			this._up0 = new THREE.Vector3();
			this._zoom0 = 1;
			this._fov0 = 0;
			this._initialNear = 0;
			this._nearPos0 = 0;
			this._initialFar = 0;
			this._farPos0 = 0;
			this._cameraMatrixState0 = new THREE.Matrix4();
			this._gizmoMatrixState0 = new THREE.Matrix4();

			//pointers array
			this._button = - 1;
			this._touchStart = [];
			this._touchCurrent = [];
			this._input = INPUT.NONE;

			//two fingers touch interaction
			this._switchSensibility = 32; //minimum movement to be performed to fire single pan start after the second finger has been released
			this._startFingerDistance = 0; //distance between two fingers
			this._currentFingerDistance = 0;
			this._startFingerRotation = 0; //amount of rotation performed with two fingers
			this._currentFingerRotation = 0;

			//double tap
			this._devPxRatio = 0;
			this._downValid = true;
			this._nclicks = 0;
			this._downEvents = [];
			this._downStart = 0; //pointerDown time
			this._clickStart = 0; //first click time
			this._maxDownTime = 250;
			this._maxInterval = 300;
			this._posThreshold = 24;
			this._movementThreshold = 24;

			//cursor positions
			this._currentCursorPosition = new THREE.Vector3();
			this._startCursorPosition = new THREE.Vector3();

			//grid
			this._grid = null; //grid to be visualized during pan operation
			this._gridPosition = new THREE.Vector3();

			//gizmos
			this._gizmos = new THREE.Group();
			this._curvePts = 128;

			//animations
			this._timeStart = - 1; //initial time
			this._animationId = - 1;

			//focus animation
			this.focusAnimationTime = 500; //duration of focus animation in ms

			//rotate animation
			this._timePrev = 0; //time at which previous rotate operation has been detected
			this._timeCurrent = 0; //time at which current rotate operation has been detected
			this._anglePrev = 0; //angle of previous rotation
			this._angleCurrent = 0; //angle of current rotation
			this._cursorPosPrev = new THREE.Vector3(); //cursor position when previous rotate operation has been detected
			this._cursorPosCurr = new THREE.Vector3(); //cursor position when current rotate operation has been detected
			this._wPrev = 0; //angular velocity of the previous rotate operation
			this._wCurr = 0; //angular velocity of the current rotate operation

			//parameters
			this.adjustNearFar = false;
			this.scaleFactor = 1.1; //zoom/distance multiplier
			this.dampingFactor = 25;
			this.wMax = 20; //maximum angular velocity allowed
			this.enableAnimations = true; //if animations should be performed
			this.enableGrid = false; //if grid should be showed during pan operation
			this.cursorZoom = false; //if wheel zoom should be cursor centered
			this.minFov = 5;
			this.maxFov = 90;
			this.enabled = true;
			this.enablePan = true;
			this.enableRotate = true;
			this.enableZoom = true;
			this.enableGizmos = true;
			this.minDistance = 0;
			this.maxDistance = Infinity;
			this.minZoom = 0;
			this.maxZoom = Infinity;

			//trackball parameters
			this._tbRadius = 1;

			//FSA
			this._state = STATE.IDLE;
			this.setCamera( _camera );
			if ( this.scene != null ) {

				this.scene.add( this._gizmos );

			}

			this.domElement.style.touchAction = 'none';
			this._devPxRatio = window.devicePixelRatio;
			this.initializeMouseActions();
			this.domElement.addEventListener( 'contextmenu', this.onContextMenu );
			this.domElement.addEventListener( 'wheel', this.onWheel );
			this.domElement.addEventListener( 'pointerdown', this.onPointerDown );
			this.domElement.addEventListener( 'pointercancel', this.onPointerCancel );
			window.addEventListener( 'resize', this.onWindowResize );

		}

		//listeners

		/**
   * Apply a transformation matrix, to the camera and gizmos
   * @param {Object} transformation Object containing matrices to apply to camera and gizmos
   */
		applyTransformMatrix( transformation ) {

			if ( transformation.camera != null ) {

				this._m4_1.copy( this._cameraMatrixState ).premultiply( transformation.camera );
				this._m4_1.decompose( this.camera.position, this.camera.quaternion, this.camera.scale );
				this.camera.updateMatrix();

				//update camera up vector
				if ( this._state == STATE.ROTATE || this._state == STATE.ZROTATE || this._state == STATE.ANIMATION_ROTATE ) {

					this.camera.up.copy( this._upState ).applyQuaternion( this.camera.quaternion );

				}

			}

			if ( transformation.gizmos != null ) {

				this._m4_1.copy( this._gizmoMatrixState ).premultiply( transformation.gizmos );
				this._m4_1.decompose( this._gizmos.position, this._gizmos.quaternion, this._gizmos.scale );
				this._gizmos.updateMatrix();

			}

			if ( this._state == STATE.SCALE || this._state == STATE.FOCUS || this._state == STATE.ANIMATION_FOCUS ) {

				this._tbRadius = this.calculateTbRadius( this.camera );
				if ( this.adjustNearFar ) {

					const cameraDistance = this.camera.position.distanceTo( this._gizmos.position );
					const bb = new THREE.Box3();
					bb.setFromObject( this._gizmos );
					const sphere = new THREE.Sphere();
					bb.getBoundingSphere( sphere );
					const adjustedNearPosition = Math.max( this._nearPos0, sphere.radius + sphere.center.length() );
					const regularNearPosition = cameraDistance - this._initialNear;
					const minNearPos = Math.min( adjustedNearPosition, regularNearPosition );
					this.camera.near = cameraDistance - minNearPos;
					const adjustedFarPosition = Math.min( this._farPos0, - sphere.radius + sphere.center.length() );
					const regularFarPosition = cameraDistance - this._initialFar;
					const minFarPos = Math.min( adjustedFarPosition, regularFarPosition );
					this.camera.far = cameraDistance - minFarPos;
					this.camera.updateProjectionMatrix();

				} else {

					let update = false;
					if ( this.camera.near != this._initialNear ) {

						this.camera.near = this._initialNear;
						update = true;

					}

					if ( this.camera.far != this._initialFar ) {

						this.camera.far = this._initialFar;
						update = true;

					}

					if ( update ) {

						this.camera.updateProjectionMatrix();

					}

				}

			}

		}

		/**
   * Calculate the angular speed
   * @param {Number} p0 Position at t0
   * @param {Number} p1 Position at t1
   * @param {Number} t0 Initial time in milliseconds
   * @param {Number} t1 Ending time in milliseconds
   */

		/**
   * Set gizmos visibility
   * @param {Boolean} value Value of gizmos visibility
   */
		setGizmosVisible( value ) {

			this._gizmos.visible = value;
			this.dispatchEvent( _changeEvent );

		}

		/**
   * Set gizmos radius factor and redraws gizmos
   * @param {Float} value Value of radius factor
   */
		setTbRadius( value ) {

			this.radiusFactor = value;
			this._tbRadius = this.calculateTbRadius( this.camera );
			const curve = new THREE.EllipseCurve( 0, 0, this._tbRadius, this._tbRadius );
			const points = curve.getPoints( this._curvePts );
			const curveGeometry = new THREE.BufferGeometry().setFromPoints( points );
			for ( const gizmo in this._gizmos.children ) {

				this._gizmos.children[ gizmo ].geometry = curveGeometry;

			}

			this.dispatchEvent( _changeEvent );

		}

		/**
   * Creates the rotation gizmos matching trackball center and radius
   * @param {Vector3} tbCenter The trackball center
   * @param {number} tbRadius The trackball radius
   */

		/**
   * Set values in transformation object
   * @param {Matrix4} camera Transformation to be applied to the camera
   * @param {Matrix4} gizmos Transformation to be applied to gizmos
   */
		setTransformationMatrices( camera = null, gizmos = null ) {

			if ( camera != null ) {

				if ( _transformation.camera != null ) {

					_transformation.camera.copy( camera );

				} else {

					_transformation.camera = camera.clone();

				}

			} else {

				_transformation.camera = null;

			}

			if ( gizmos != null ) {

				if ( _transformation.gizmos != null ) {

					_transformation.gizmos.copy( gizmos );

				} else {

					_transformation.gizmos = gizmos.clone();

				}

			} else {

				_transformation.gizmos = null;

			}

		}

		/**
   * Rotate camera around its direction axis passing by a given point by a given angle
   * @param {Vector3} point The point where the rotation axis is passing trough
   * @param {Number} angle Angle in radians
   * @returns The computed transormation matix
   */

		getRaycaster() {

			return _raycaster;

		}

		/**
   * Unproject the cursor on the 3D object surface
   * @param {Vector2} cursor Cursor coordinates in NDC
   * @param {Camera} camera Virtual camera
   * @returns {Vector3} The point of intersection with the model, if exist, null otherwise
   */

	}

	THREE.ArcballControls = ArcballControls;

} )();