source: js/viewer-f0/js/library/OrbitControls.js @ 208

/**
 * @author qiao / https://github.com/qiao
 * @author mrdoob / http://mrdoob.com
 * @author alteredq / http://alteredqualia.com/
 * @author WestLangley / http://github.com/WestLangley
 * @author erich666 / http://erichaines.com
 */
/*global THREE, console */

// This set of controls performs orbiting, dollying (zooming), and panning. It maintains
// the "up" direction as +Y, unlike the TrackballControls. Touch on tablet and phones is
// supported.
//
//    Orbit - left mouse / touch: one finger move
//    Zoom - middle mouse, or mousewheel / touch: two finger spread or squish
//    Pan - right mouse, or arrow keys / touch: three finter swipe
//
// This is a drop-in replacement for (most) TrackballControls used in examples.
// That is, include this js file and wherever you see:
//      controls = new THREE.TrackballControls( camera );
//      controls.target.z = 150;
// Simple substitute "OrbitControls" and the control should work as-is.

THREE.OrbitControls = function ( object, domElement ) {

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

        // API

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

        // "target" sets the location of focus, where the control orbits around
        // and where it pans with respect to.
        this.target = new THREE.Vector3();
        // center is old, deprecated; use "target" instead
        this.center = this.target;

        // This option actually enables dollying in and out; left as "zoom" for
        // backwards compatibility
        this.noZoom = false;
        this.zoomSpeed = 1.0;
        // Limits to how far you can dolly in and out
        this.minDistance = 0;
        this.maxDistance = Infinity;

        // Set to true to disable this control
        this.noRotate = false;
        this.rotateSpeed = 1.0;

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

        // Set to true to automatically rotate around the target
        this.autoRotate = false;
        this.autoRotateSpeed = 2.0; // 30 seconds per round when fps is 60

        // How far you can orbit vertically, upper and lower limits.
        // Range is 0 to Math.PI radians.
        this.minPolarAngle = 0; // radians
        this.maxPolarAngle = Math.PI; // radians

        // Set to true to disable use of the keys
        this.noKeys = false;
        // The four arrow keys
        this.keys = { LEFT: 37, UP: 38, RIGHT: 39, BOTTOM: 40 };

        ////////////
        // internals

        var scope = this;

        var EPS = 0.000001;

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

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

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

        var phiDelta = 0;
        var thetaDelta = 0;
        var scale = 1;
        var pan = new THREE.Vector3();

        var lastPosition = new THREE.Vector3();

        var STATE = { NONE : -1, ROTATE : 0, DOLLY : 1, PAN : 2, TOUCH_ROTATE : 3, TOUCH_DOLLY : 4, TOUCH_PAN : 5 };
        var state = STATE.NONE;

        // events

        var changeEvent = { type: 'change' };


        this.rotateLeft = function ( angle ) {

                if ( angle === undefined ) {

                        angle = getAutoRotationAngle();

                }

                thetaDelta -= angle;

        };

        this.rotateUp = function ( angle ) {

                if ( angle === undefined ) {

                        angle = getAutoRotationAngle();

                }

                phiDelta -= angle;

        };

        // pass in distance in world space to move left
        this.panLeft = function ( distance ) {

                var panOffset = new THREE.Vector3();
                var te = this.object.matrix.elements;
                // get X column of matrix
                panOffset.set( te[0], te[1], te[2] );
                panOffset.multiplyScalar(-distance);
                
                pan.add( panOffset );

        };

        // pass in distance in world space to move up
        this.panUp = function ( distance ) {

                var panOffset = new THREE.Vector3();
                var te = this.object.matrix.elements;
                // get Y column of matrix
                panOffset.set( te[4], te[5], te[6] );
                panOffset.multiplyScalar(distance);
                
                pan.add( panOffset );
        };
        
        // main entry point; pass in Vector2 of change desired in pixel space,
        // right and down are positive
        this.pan = function ( delta ) {

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

                if ( scope.object.fov !== undefined ) {

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

                        // half of the fov is center to top of screen
                        targetDistance *= Math.tan( (scope.object.fov/2) * Math.PI / 180.0 );
                        // we actually don't use screenWidth, since perspective camera is fixed to screen height
                        scope.panLeft( 2 * delta.x * targetDistance / element.clientHeight );
                        scope.panUp( 2 * delta.y * targetDistance / element.clientHeight );

                } else if ( scope.object.top !== undefined ) {

                        // orthographic
                        scope.panLeft( delta.x * (scope.object.right - scope.object.left) / element.clientWidth );
                        scope.panUp( delta.y * (scope.object.top - scope.object.bottom) / element.clientHeight );

                } else {

                        // camera neither orthographic or perspective - warn user
                        console.warn( 'WARNING: OrbitControls.js encountered an unknown camera type - pan disabled.' );

                }

        };

        this.dollyIn = function ( dollyScale ) {

                if ( dollyScale === undefined ) {

                        dollyScale = getZoomScale();

                }

                scale /= dollyScale;

        };

        this.dollyOut = function ( dollyScale ) {

                if ( dollyScale === undefined ) {

                        dollyScale = getZoomScale();

                }

                scale *= dollyScale;

        };

        this.update = function () {

                var position = this.object.position;
                var offset = position.clone().sub( this.target );

                // angle from z-axis around y-axis

                var theta = Math.atan2( offset.x, offset.z );

                // angle from y-axis

                var phi = Math.atan2( Math.sqrt( offset.x * offset.x + offset.z * offset.z ), offset.y );

                if ( this.autoRotate ) {

                        this.rotateLeft( getAutoRotationAngle() );

                }

                theta += thetaDelta;
                phi += phiDelta;

                // restrict phi to be between desired limits
                phi = Math.max( this.minPolarAngle, Math.min( this.maxPolarAngle, phi ) );

                // restrict phi to be betwee EPS and PI-EPS
                phi = Math.max( EPS, Math.min( Math.PI - EPS, phi ) );

                var radius = offset.length() * scale;

                // restrict radius to be between desired limits
                radius = Math.max( this.minDistance, Math.min( this.maxDistance, radius ) );
                
                // move target to panned location
                this.target.add( pan );

                offset.x = radius * Math.sin( phi ) * Math.sin( theta );
                offset.y = radius * Math.cos( phi );
                offset.z = radius * Math.sin( phi ) * Math.cos( theta );

                position.copy( this.target ).add( offset );

                this.object.lookAt( this.target );

                thetaDelta = 0;
                phiDelta = 0;
                scale = 1;
                pan.set(0,0,0);

                if ( lastPosition.distanceTo( this.object.position ) > 0 ) {

                        this.dispatchEvent( changeEvent );

                        lastPosition.copy( this.object.position );

                }

        };


        function getAutoRotationAngle() {

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

        }

        function getZoomScale() {

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

        }

        function onMouseDown( event ) {

                if ( scope.enabled === false ) { return; }
                event.preventDefault();

                if ( event.button === 0 ) {
                        if ( scope.noRotate === true ) { return; }

                        state = STATE.ROTATE;

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

                } else if ( event.button === 1 ) {
                        if ( scope.noZoom === true ) { return; }

                        state = STATE.DOLLY;

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

                } else if ( event.button === 2 ) {
                        if ( scope.noPan === true ) { return; }

                        state = STATE.PAN;

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

                }

                // Greggman fix: https://github.com/greggman/three.js/commit/fde9f9917d6d8381f06bf22cdff766029d1761be
                scope.domElement.addEventListener( 'mousemove', onMouseMove, false );
                scope.domElement.addEventListener( 'mouseup', onMouseUp, false );

        }

        function onMouseMove( event ) {

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

                event.preventDefault();

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

                if ( state === STATE.ROTATE ) {

                        if ( scope.noRotate === true ) return;

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

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

                        rotateStart.copy( rotateEnd );

                } else if ( state === STATE.DOLLY ) {

                        if ( scope.noZoom === true ) return;

                        dollyEnd.set( event.clientX, event.clientY );
                        dollyDelta.subVectors( dollyEnd, dollyStart );

                        if ( dollyDelta.y > 0 ) {

                                scope.dollyIn();

                        } else {

                                scope.dollyOut();

                        }

                        dollyStart.copy( dollyEnd );

                } else if ( state === STATE.PAN ) {

                        if ( scope.noPan === true ) return;

                        panEnd.set( event.clientX, event.clientY );
                        panDelta.subVectors( panEnd, panStart );
                        
                        scope.pan( panDelta );

                        panStart.copy( panEnd );

                }

                // Greggman fix: https://github.com/greggman/three.js/commit/fde9f9917d6d8381f06bf22cdff766029d1761be
                scope.update();

        }

        function onMouseUp( /* event */ ) {

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

                // Greggman fix: https://github.com/greggman/three.js/commit/fde9f9917d6d8381f06bf22cdff766029d1761be
                scope.domElement.removeEventListener( 'mousemove', onMouseMove, false );
                scope.domElement.removeEventListener( 'mouseup', onMouseUp, false );

                state = STATE.NONE;

        }

        function onMouseWheel( event ) {

                if ( scope.enabled === false || scope.noZoom === true ) return;

                var delta = 0;

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

                        delta = event.wheelDelta;

                } else if ( event.detail ) { // Firefox

                        delta = - event.detail;

                }

                if ( delta > 0 ) {

                        scope.dollyOut();

                } else {

                        scope.dollyIn();

                }

        }

        function onKeyDown( event ) {

                if ( scope.enabled === false ) { return; }
                if ( scope.noKeys === true ) { return; }
                if ( scope.noPan === true ) { return; }

                // pan a pixel - I guess for precise positioning?
                // Greggman fix: https://github.com/greggman/three.js/commit/fde9f9917d6d8381f06bf22cdff766029d1761be
                var needUpdate = false;
                
                switch ( event.keyCode ) {

                        case scope.keys.UP:
                                scope.pan( new THREE.Vector2( 0, scope.keyPanSpeed ) );
                                needUpdate = true;
                                break;
                        case scope.keys.BOTTOM:
                                scope.pan( new THREE.Vector2( 0, -scope.keyPanSpeed ) );
                                needUpdate = true;
                                break;
                        case scope.keys.LEFT:
                                scope.pan( new THREE.Vector2( scope.keyPanSpeed, 0 ) );
                                needUpdate = true;
                                break;
                        case scope.keys.RIGHT:
                                scope.pan( new THREE.Vector2( -scope.keyPanSpeed, 0 ) );
                                needUpdate = true;
                                break;
                }

                // Greggman fix: https://github.com/greggman/three.js/commit/fde9f9917d6d8381f06bf22cdff766029d1761be
                if ( needUpdate ) {

                        scope.update();

                }

        }
        
        function touchstart( event ) {

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

                switch ( event.touches.length ) {

                        case 1: // one-fingered touch: rotate
                                if ( scope.noRotate === true ) { return; }

                                state = STATE.TOUCH_ROTATE;

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

                        case 2: // two-fingered touch: dolly
                                if ( scope.noZoom === true ) { return; }

                                state = STATE.TOUCH_DOLLY;

                                var dx = event.touches[ 0 ].pageX - event.touches[ 1 ].pageX;
                                var dy = event.touches[ 0 ].pageY - event.touches[ 1 ].pageY;
                                var distance = Math.sqrt( dx * dx + dy * dy );
                                dollyStart.set( 0, distance );
                                break;

                        case 3: // three-fingered touch: pan
                                if ( scope.noPan === true ) { return; }

                                state = STATE.TOUCH_PAN;

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

                        default:
                                state = STATE.NONE;

                }
        }

        function touchmove( event ) {

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

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

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

                switch ( event.touches.length ) {

                        case 1: // one-fingered touch: rotate
                                if ( scope.noRotate === true ) { return; }
                                if ( state !== STATE.TOUCH_ROTATE ) { return; }

                                rotateEnd.set( event.touches[ 0 ].pageX, event.touches[ 0 ].pageY );
                                rotateDelta.subVectors( rotateEnd, rotateStart );

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

                                rotateStart.copy( rotateEnd );
                                break;

                        case 2: // two-fingered touch: dolly
                                if ( scope.noZoom === true ) { return; }
                                if ( state !== STATE.TOUCH_DOLLY ) { return; }

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

                                dollyEnd.set( 0, distance );
                                dollyDelta.subVectors( dollyEnd, dollyStart );

                                if ( dollyDelta.y > 0 ) {

                                        scope.dollyOut();

                                } else {

                                        scope.dollyIn();

                                }

                                dollyStart.copy( dollyEnd );
                                break;

                        case 3: // three-fingered touch: pan
                                if ( scope.noPan === true ) { return; }
                                if ( state !== STATE.TOUCH_PAN ) { return; }

                                panEnd.set( event.touches[ 0 ].pageX, event.touches[ 0 ].pageY );
                                panDelta.subVectors( panEnd, panStart );
                                
                                scope.pan( panDelta );

                                panStart.copy( panEnd );
                                break;

                        default:
                                state = STATE.NONE;

                }

        }

        function touchend( /* event */ ) {

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

                state = STATE.NONE;
        }

        this.domElement.addEventListener( 'contextmenu', function ( event ) { event.preventDefault(); }, false );
        this.domElement.addEventListener( 'mousedown', onMouseDown, false );
        this.domElement.addEventListener( 'mousewheel', onMouseWheel, false );
        this.domElement.addEventListener( 'DOMMouseScroll', onMouseWheel, false ); // firefox

        this.domElement.addEventListener( 'keydown', onKeyDown, false );

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

};

THREE.OrbitControls.prototype = Object.create( THREE.EventDispatcher.prototype );