var camera;
    // once everything is loaded, we run our Three.js stuff.
    function init() {

        var stats = initStats();

        // create a scene, that will hold all our elements such as objects, cameras and lights.
        var scene = new THREE.Scene();

        // create a camera, which defines where we're looking at.
        camera = new THREE.PerspectiveCamera(45, window.innerWidth / window.innerHeight, 0.1, 1000);
        scene.add(camera);


        // create a render and set the size
//        var renderer = new THREE.WebGLRenderer();
        var renderer = new THREE.WebGLDeferredRenderer({
            width: window.innerWidth,
            height: window.innerHeight,
            scale: 1, antialias: true,
            tonemapping: THREE.FilmicOperator, brightness: 2.5
        });

//        renderer.setSize(window.innerWidth, window.innerHeight);
//        renderer.shadowMapEnabled = true;

        // create the ground plane
        var planeGeometry = new THREE.PlaneGeometry(70, 70, 1, 1);
        var planeMaterial = new THREE.MeshPhongMaterial({color: 0xffffff, specular: 0xffffff, shininess: 200});
        var plane = new THREE.Mesh(planeGeometry, planeMaterial);
        // plane.receiveShadow  = true;

        // rotate and position the plane
        plane.rotation.x = -0.5 * Math.PI;
        plane.position.x = 0;
        plane.position.y = 0;
        plane.position.z = 0;

        // add the plane to the scene
        scene.add(plane);

        // position and point the camera to the center of the scene
        camera.position.x = 20;
        camera.position.y = 30;
        camera.position.z = 21;
        camera.lookAt(new THREE.Vector3(0, 0, -30));

        // add the output of the renderer to the html element
        document.getElementById("WebGL-output").appendChild(renderer.domElement);

        // call the render function
        var step = 0;


        var spotLight0 = new THREE.SpotLight(0xcccccc);
        spotLight0.position.set(-40, 60, -10);
        spotLight0.intensity = 0.1;
        spotLight0.lookAt(plane);
        scene.add(spotLight0);


        var areaLight1 = new THREE.AreaLight(0xff0000, 3);
        areaLight1.position.set(-10, 10, -35);
        areaLight1.rotation.set(-Math.PI / 2, 0, 0);
        areaLight1.width = 4;
        areaLight1.height = 9.9;
        scene.add(areaLight1);

        var areaLight2 = new THREE.AreaLight(0x00ff00, 3);
        areaLight2.position.set(0, 10, -35);
        areaLight2.rotation.set(-Math.PI / 2, 0, 0);
        areaLight2.width = 4;
        areaLight2.height = 9.9;
        scene.add(areaLight2);

        var areaLight3 = new THREE.AreaLight(0x0000ff, 3);
        areaLight3.position.set(10, 10, -35);
        areaLight3.rotation.set(-Math.PI / 2, 0, 0);
        areaLight3.width = 4;
        areaLight3.height = 9.9;
        scene.add(areaLight3);

        var planeGeometry1 = new THREE.BoxGeometry(4, 10, 0);
        var planeGeometry1Mat = new THREE.MeshBasicMaterial({color: 0xff0000});
        var plane1 = new THREE.Mesh(planeGeometry1, planeGeometry1Mat);
        plane1.position.copy(areaLight1.position);
        scene.add(plane1);


        var planeGeometry2 = new THREE.BoxGeometry(4, 10, 0);
        var planeGeometry2Mat = new THREE.MeshBasicMaterial({color: 0x00ff00});
        var plane2 = new THREE.Mesh(planeGeometry2, planeGeometry2Mat);

        plane2.position.copy(areaLight2.position);
        scene.add(plane2);

        var planeGeometry3 = new THREE.BoxGeometry(4, 10, 0);
        var planeGeometry3Mat = new THREE.MeshBasicMaterial({color: 0x0000ff});
        var plane3 = new THREE.Mesh(planeGeometry3, planeGeometry3Mat);

        plane3.position.copy(areaLight3.position);
        scene.add(plane3);


        var controls = new function () {
            this.rotationSpeed = 0.02;
            this.color1 = 0xff0000;
            this.intensity1 = 2;
            this.color2 = 0x00ff00;
            this.intensity2 = 2;
            this.color3 = 0x0000ff;
            this.intensity3 = 2;
        };

        var gui = new dat.GUI();
        gui.addColor(controls, 'color1').onChange(function (e) {
            areaLight1.color = new THREE.Color(e);
            planeGeometry1Mat.color = new THREE.Color(e);
            scene.remove(plane1);
            plane1 = new THREE.Mesh(planeGeometry1, planeGeometry1Mat);
            plane1.position.copy(areaLight1.position);
            scene.add(plane1);

        });
        gui.add(controls, 'intensity1', 0, 5).onChange(function (e) {
            areaLight1.intensity = e;
        });
        gui.addColor(controls, 'color2').onChange(function (e) {
            areaLight2.color = new THREE.Color(e);
            planeGeometry2Mat.color = new THREE.Color(e);
            scene.remove(plane2);
            plane2 = new THREE.Mesh(planeGeometry2, planeGeometry2Mat);
            plane2.position.copy(areaLight2.position);
            scene.add(plane2);
        });
        gui.add(controls, 'intensity2', 0, 5).onChange(function (e) {
            areaLight2.intensity = e;
        });
        gui.addColor(controls, 'color3').onChange(function (e) {
            areaLight3.color = new THREE.Color(e);
            planeGeometry3Mat.color = new THREE.Color(e);
            scene.remove(plane3);
            plane3 = new THREE.Mesh(planeGeometry1, planeGeometry3Mat);
            plane3.position.copy(areaLight3.position);
            scene.add(plane3);
        });
        gui.add(controls, 'intensity3', 0, 5).onChange(function (e) {
            areaLight3.intensity = e;
        });


        render();

        function render() {
            stats.update();

            // render using requestAnimationFrame
            requestAnimationFrame(render);
            renderer.render(scene, camera);
        }

        function initStats() {

            var stats = new Stats();

            stats.setMode(0); // 0: fps, 1: ms

            // Align top-left
            stats.domElement.style.position = 'absolute';
            stats.domElement.style.left = '0px';
            stats.domElement.style.top = '0px';

            document.getElementById("Stats-output").appendChild(stats.domElement);

            return stats;
        }
    }
    window.onload = init;