<!DOCTYPE html>
<html lang="en">
<head>
    <title>冥想圣地</title>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0">
    <style>
        body {
            color: #808080;
            font-family:Monospace;
            font-size:13px;
            text-align:center;

            background-color: #ffffff;
            margin: 0px;
            overflow: hidden;
        }

        #info {
            position: absolute;
            top: 0px; width: 100%;
            padding: 5px;
        }
    </style>
</head>
<body>

<div id="container"></div>

<script src="${ctxPath}/threejs/three.min.js"></script>

<script src="${ctxPath}/threejs/renderers/Projector.js"></script>
<script src="${ctxPath}/threejs/renderers/CanvasRenderer.js"></script>

<script src="${ctxPath}/threejs/lib/stats.min.js"></script>

<script src="${ctxPath}/threejs/obj/Bird.js"></script>

<script>

    // Based on http://www.openprocessing.org/visuals/?visualID=6910

    var Boid = function() {

        var vector = new THREE.Vector3(),
            _acceleration, _width = 500, _height = 500, _depth = 200, _goal, _neighborhoodRadius = 100,
            _maxSpeed = 4, _maxSteerForce = 0.1, _avoidWalls = false;

        this.position = new THREE.Vector3();
        this.velocity = new THREE.Vector3();
        _acceleration = new THREE.Vector3();

        this.setGoal = function ( target ) {

            _goal = target;

        };

        this.setAvoidWalls = function ( value ) {

            _avoidWalls = value;

        };

        this.setWorldSize = function ( width, height, depth ) {

            _width = width;
            _height = height;
            _depth = depth;

        };

        this.run = function ( boids ) {

            if ( _avoidWalls ) {

                vector.set( - _width, this.position.y, this.position.z );
                vector = this.avoid( vector );
                vector.multiplyScalar( 5 );
                _acceleration.add( vector );

                vector.set( _width, this.position.y, this.position.z );
                vector = this.avoid( vector );
                vector.multiplyScalar( 5 );
                _acceleration.add( vector );

                vector.set( this.position.x, - _height, this.position.z );
                vector = this.avoid( vector );
                vector.multiplyScalar( 5 );
                _acceleration.add( vector );

                vector.set( this.position.x, _height, this.position.z );
                vector = this.avoid( vector );
                vector.multiplyScalar( 5 );
                _acceleration.add( vector );

                vector.set( this.position.x, this.position.y, - _depth );
                vector = this.avoid( vector );
                vector.multiplyScalar( 5 );
                _acceleration.add( vector );

                vector.set( this.position.x, this.position.y, _depth );
                vector = this.avoid( vector );
                vector.multiplyScalar( 5 );
                _acceleration.add( vector );

            }/* else {

             this.checkBounds();

             }
             */

            if ( Math.random() > 0.5 ) {

                this.flock( boids );

            }

            this.move();

        };

        this.flock = function ( boids ) {

            if ( _goal ) {

                _acceleration.add( this.reach( _goal, 0.005 ) );

            }

            _acceleration.add( this.alignment( boids ) );
            _acceleration.add( this.cohesion( boids ) );
            _acceleration.add( this.separation( boids ) );

        };

        this.move = function () {

            this.velocity.add( _acceleration );

            var l = this.velocity.length();

            if ( l > _maxSpeed ) {

                this.velocity.divideScalar( l / _maxSpeed );

            }

            this.position.add( this.velocity );
            _acceleration.set( 0, 0, 0 );

        };

        this.checkBounds = function () {

            if ( this.position.x >   _width ) this.position.x = - _width;
            if ( this.position.x < - _width ) this.position.x =   _width;
            if ( this.position.y >   _height ) this.position.y = - _height;
            if ( this.position.y < - _height ) this.position.y =  _height;
            if ( this.position.z >  _depth ) this.position.z = - _depth;
            if ( this.position.z < - _depth ) this.position.z =  _depth;

        };

        //

        this.avoid = function ( target ) {

            var steer = new THREE.Vector3();

            steer.copy( this.position );
            steer.sub( target );

            steer.multiplyScalar( 1 / this.position.distanceToSquared( target ) );

            return steer;

        };

        this.repulse = function ( target ) {

            var distance = this.position.distanceTo( target );

            if ( distance < 150 ) {

                var steer = new THREE.Vector3();

                steer.subVectors( this.position, target );
                steer.multiplyScalar( 0.5 / distance );

                _acceleration.add( steer );

            }

        };

        this.reach = function ( target, amount ) {

            var steer = new THREE.Vector3();

            steer.subVectors( target, this.position );
            steer.multiplyScalar( amount );

            return steer;

        };

        this.alignment = function ( boids ) {

            var count = 0;
            var velSum = new THREE.Vector3();

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

                if ( Math.random() > 0.6 ) continue;

                var boid = boids[ i ];
                var distance = boid.position.distanceTo( this.position );

                if ( distance > 0 && distance <= _neighborhoodRadius ) {

                    velSum.add( boid.velocity );
                    count++;

                }

            }

            if ( count > 0 ) {

                velSum.divideScalar( count );

                var l = velSum.length();

                if ( l > _maxSteerForce ) {

                    velSum.divideScalar( l / _maxSteerForce );

                }

            }

            return velSum;

        };

        this.cohesion = function ( boids ) {

            var count = 0;
            var posSum = new THREE.Vector3();
            var steer = new THREE.Vector3();

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

                if ( Math.random() > 0.6 ) continue;

                var boid = boids[ i ];
                var distance = boid.position.distanceTo( this.position );

                if ( distance > 0 && distance <= _neighborhoodRadius ) {

                    posSum.add( boid.position );
                    count++;

                }

            }

            if ( count > 0 ) {

                posSum.divideScalar( count );

            }

            steer.subVectors( posSum, this.position );

            var l = steer.length();

            if ( l > _maxSteerForce ) {

                steer.divideScalar( l / _maxSteerForce );

            }

            return steer;

        };

        this.separation = function ( boids ) {

            var posSum = new THREE.Vector3();
            var repulse = new THREE.Vector3();

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

                if ( Math.random() > 0.6 ) continue;

                var boid = boids[ i ];
                var distance = boid.position.distanceTo( this.position );

                if ( distance > 0 && distance <= _neighborhoodRadius ) {

                    repulse.subVectors( this.position, boid.position );
                    repulse.normalize();
                    repulse.divideScalar( distance );
                    posSum.add( repulse );

                }

            }

            return posSum;

        }

    }

</script>

<script>

    var SCREEN_WIDTH = window.innerWidth,
        SCREEN_HEIGHT = window.innerHeight,
        SCREEN_WIDTH_HALF = SCREEN_WIDTH  / 2,
        SCREEN_HEIGHT_HALF = SCREEN_HEIGHT / 2;

    var camera, scene, renderer,
        birds, bird;

    var boid, boids;

    var stats;

    init();
    animate();

    function init() {

        camera = new THREE.PerspectiveCamera( 75, SCREEN_WIDTH / SCREEN_HEIGHT, 1, 10000 );
        camera.position.z = 450;

        scene = new THREE.Scene();
        scene.background = new THREE.Color( 0xffffff );

        birds = [];
        boids = [];

        for ( var i = 0; i < 200; i ++ ) {

            boid = boids[ i ] = new Boid();
            boid.position.x = Math.random() * 400 - 200;
            boid.position.y = Math.random() * 400 - 200;
            boid.position.z = Math.random() * 400 - 200;
            boid.velocity.x = Math.random() * 2 - 1;
            boid.velocity.y = Math.random() * 2 - 1;
            boid.velocity.z = Math.random() * 2 - 1;
            boid.setAvoidWalls( true );
            boid.setWorldSize( 500, 500, 400 );

            bird = birds[ i ] = new THREE.Mesh( new Bird(), new THREE.MeshBasicMaterial( { color:Math.random() * 0xffffff, side: THREE.DoubleSide } ) );
            bird.phase = Math.floor( Math.random() * 62.83 );
            scene.add( bird );


        }

        renderer = new THREE.CanvasRenderer();
        renderer.setPixelRatio( window.devicePixelRatio );
        renderer.setSize( SCREEN_WIDTH, SCREEN_HEIGHT );

        document.addEventListener( 'mousemove', onDocumentMouseMove, false );
        document.body.appendChild( renderer.domElement );

        stats = new Stats();
        document.getElementById( 'container' ).appendChild(stats.dom);

        //

        window.addEventListener( 'resize', onWindowResize, false );

    }

    function onWindowResize() {

        camera.aspect = window.innerWidth / window.innerHeight;
        camera.updateProjectionMatrix();

        renderer.setSize( window.innerWidth, window.innerHeight );

    }

    function onDocumentMouseMove( event ) {

        var vector = new THREE.Vector3( event.clientX - SCREEN_WIDTH_HALF, - event.clientY + SCREEN_HEIGHT_HALF, 0 );

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

            boid = boids[ i ];

            vector.z = boid.position.z;

            boid.repulse( vector );

        }

    }

    //

    function animate() {

        requestAnimationFrame( animate );

        stats.begin();
        render();
        stats.end();

    }

    function render() {

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

            boid = boids[ i ];
            boid.run( boids );

            bird = birds[ i ];
            bird.position.copy( boids[ i ].position );

            var color = bird.material.color;
            color.r = color.g = color.b = ( 500 - bird.position.z ) / 1000;

            bird.rotation.y = Math.atan2( - boid.velocity.z, boid.velocity.x );
            bird.rotation.z = Math.asin( boid.velocity.y / boid.velocity.length() );

            bird.phase = ( bird.phase + ( Math.max( 0, bird.rotation.z ) + 0.1 )  ) % 62.83;
            bird.geometry.vertices[ 5 ].y = bird.geometry.vertices[ 4 ].y = Math.sin( bird.phase ) * 5;

        }

        renderer.render( scene, camera );

    }

</script>

</body>
</html>
