source: other-projects/playing-in-the-street/summer-2013/trunk/Playing-in-the-Street-WPF/Content/Web/mrdoob-three.js-4862f5f/src/extras/helpers/CameraHelper.js@ 28897

/**
 * @author alteredq / http://alteredqualia.com/
 *
 *  - shows frustum, line of sight and up of the camera
 *  - suitable for fast updates
 *  - based on frustum visualization in lightgl.js shadowmap example
 *      http://evanw.github.com/lightgl.js/tests/shadowmap.html
 */

THREE.CameraHelper = function ( camera ) {

    var geometry = new THREE.Geometry();
    var material = new THREE.LineBasicMaterial( { color: 0xffffff, vertexColors: THREE.FaceColors } );

    var pointMap = {};

    // colors

    var hexFrustum = 0xffaa00;
    var hexCone = 0xff0000;
    var hexUp = 0x00aaff;
    var hexTarget = 0xffffff;
    var hexCross = 0x333333;

    // near

    addLine( "n1", "n2", hexFrustum );
    addLine( "n2", "n4", hexFrustum );
    addLine( "n4", "n3", hexFrustum );
    addLine( "n3", "n1", hexFrustum );

    // far

    addLine( "f1", "f2", hexFrustum );
    addLine( "f2", "f4", hexFrustum );
    addLine( "f4", "f3", hexFrustum );
    addLine( "f3", "f1", hexFrustum );

    // sides

    addLine( "n1", "f1", hexFrustum );
    addLine( "n2", "f2", hexFrustum );
    addLine( "n3", "f3", hexFrustum );
    addLine( "n4", "f4", hexFrustum );

    // cone

    addLine( "p", "n1", hexCone );
    addLine( "p", "n2", hexCone );
    addLine( "p", "n3", hexCone );
    addLine( "p", "n4", hexCone );

    // up

    addLine( "u1", "u2", hexUp );
    addLine( "u2", "u3", hexUp );
    addLine( "u3", "u1", hexUp );

    // target

    addLine( "c", "t", hexTarget );
    addLine( "p", "c", hexCross );

    // cross

    addLine( "cn1", "cn2", hexCross );
    addLine( "cn3", "cn4", hexCross );

    addLine( "cf1", "cf2", hexCross );
    addLine( "cf3", "cf4", hexCross );

    function addLine( a, b, hex ) {

        addPoint( a, hex );
        addPoint( b, hex );

    }

    function addPoint( id, hex ) {

        geometry.vertices.push( new THREE.Vector3() );
        geometry.colors.push( new THREE.Color( hex ) );

        if ( pointMap[ id ] === undefined ) {

            pointMap[ id ] = [];

        }

        pointMap[ id ].push( geometry.vertices.length - 1 );

    }

    THREE.Line.call( this, geometry, material, THREE.LinePieces );

    this.camera = camera;
    this.matrixWorld = camera.matrixWorld;
    this.matrixAutoUpdate = false;

    this.pointMap = pointMap;

    this.update();

};

THREE.CameraHelper.prototype = Object.create( THREE.Line.prototype );

THREE.CameraHelper.prototype.update = function () {

    var vector = new THREE.Vector3();
    var camera = new THREE.Camera();
    var projector = new THREE.Projector();

    return function () {

        var scope = this;

        var w = 1, h = 1;

        // we need just camera projection matrix
        // world matrix must be identity

        camera.projectionMatrix.copy( this.camera.projectionMatrix );

        // center / target

        setPoint( "c", 0, 0, -1 );
        setPoint( "t", 0, 0,  1 );

        // near

        setPoint( "n1", -w, -h, -1 );
        setPoint( "n2",  w, -h, -1 );
        setPoint( "n3", -w,  h, -1 );
        setPoint( "n4",  w,  h, -1 );

        // far

        setPoint( "f1", -w, -h, 1 );
        setPoint( "f2",  w, -h, 1 );
        setPoint( "f3", -w,  h, 1 );
        setPoint( "f4",  w,  h, 1 );

        // up

        setPoint( "u1",  w * 0.7, h * 1.1, -1 );
        setPoint( "u2", -w * 0.7, h * 1.1, -1 );
        setPoint( "u3",        0, h * 2,   -1 );

        // cross

        setPoint( "cf1", -w,  0, 1 );
        setPoint( "cf2",  w,  0, 1 );
        setPoint( "cf3",  0, -h, 1 );
        setPoint( "cf4",  0,  h, 1 );

        setPoint( "cn1", -w,  0, -1 );
        setPoint( "cn2",  w,  0, -1 );
        setPoint( "cn3",  0, -h, -1 );
        setPoint( "cn4",  0,  h, -1 );

        function setPoint( point, x, y, z ) {

            vector.set( x, y, z );
            projector.unprojectVector( vector, camera );

            var points = scope.pointMap[ point ];

            if ( points !== undefined ) {

                for ( var i = 0, il = points.length; i < il; i ++ ) {

                    scope.geometry.vertices[ points[ i ] ].copy( vector );

                }

            }

        }

        this.geometry.verticesNeedUpdate = true;

    };

}();