chapter-06/02-advanced-3d-geometries-lathe.html

<!DOCTYPE html>

<html>

<head>
    <title>Example 06.02 - Advanced 3D geometries - Lathe</title>
    <script type="text/javascript" src="../libs/three.js"></script>

    <script type="text/javascript" src="../libs/stats.js"></script>
    <script type="text/javascript" src="../libs/dat.gui.js"></script>
    <style>
        body {
            /* set margin to 0 and overflow to hidden, to go fullscreen */
            margin: 0;
            overflow: hidden;
        }
    </style>
</head>
<body>

<div id="Stats-output">
</div>
<!-- Div which will hold the Output -->
<div id="WebGL-output">
</div>

<!-- Javascript code that runs our Three.js examples -->
<script type="text/javascript">

    // 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.
        var camera = new THREE.PerspectiveCamera(45, window.innerWidth / window.innerHeight, 0.1, 1000);

        // create a render and set the size
        var webGLRenderer = new THREE.WebGLRenderer();
        webGLRenderer.setClearColor(new THREE.Color(0xEEEEEE, 1.0));
        webGLRenderer.setSize(window.innerWidth, window.innerHeight);
        webGLRenderer.shadowMapEnabled = true;

        // position and point the camera to the center of the scene
        camera.position.x = -30;
        camera.position.y = 40;
        camera.position.z = 50;
        camera.lookAt(new THREE.Vector3(10, 0, 0));

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

        // call the render function
        var step = 0;

        // the points group
        var spGroup;
        // the mesh
        var latheMesh;

        generatePoints(12, 2, 2 * Math.PI);

        // setup the control gui
        var controls = new function () {
            // we need the first child, since it's a multimaterial

            this.segments = 12;
            this.phiStart = 0;
            this.phiLength = 2 * Math.PI;

            this.redraw = function () {
                scene.remove(spGroup);
                scene.remove(latheMesh);
                generatePoints(controls.segments, controls.phiStart, controls.phiLength);
            };
        };

        var gui = new dat.GUI();
        gui.add(controls, 'segments', 0, 50).step(1).onChange(controls.redraw);
        gui.add(controls, 'phiStart', 0, 2 * Math.PI).onChange(controls.redraw);
        gui.add(controls, 'phiLength', 0, 2 * Math.PI).onChange(controls.redraw);


        render();

        function generatePoints(segments, phiStart, phiLength) {
            // add 10 random spheres
            var points = [];
            var height = 5;
            var count = 30;
            for (var i = 0; i < count; i++) {
                points.push(new THREE.Vector3((Math.sin(i * 0.2) + Math.cos(i * 0.3)) * height + 12, 0, ( i - count ) + count / 2));
            }

            spGroup = new THREE.Object3D();
            var material = new THREE.MeshBasicMaterial({color: 0xff0000, transparent: false});
            points.forEach(function (point) {

                var spGeom = new THREE.SphereGeometry(0.2);
                var spMesh = new THREE.Mesh(spGeom, material);
                spMesh.position.copy(point);
                spGroup.add(spMesh);
            });
            // add the points as a group to the scene
            scene.add(spGroup);

            // use the same points to create a LatheGeometry
            var latheGeometry = new THREE.LatheGeometry(points, segments, phiStart, phiLength);
            latheMesh = createMesh(latheGeometry);

            scene.add(latheMesh);
        }

        function createMesh(geom) {

            // assign two materials
            //  var meshMaterial = new THREE.MeshBasicMaterial({color:0x00ff00, transparent:true, opacity:0.6});
            var meshMaterial = new THREE.MeshNormalMaterial();
            meshMaterial.side = THREE.DoubleSide;
            var wireFrameMat = new THREE.MeshBasicMaterial();
            wireFrameMat.wireframe = true;

            // create a multimaterial
            var mesh = THREE.SceneUtils.createMultiMaterialObject(geom, [meshMaterial, wireFrameMat]);

            return mesh;
        }

        function render() {
            stats.update();

            spGroup.rotation.x = step;
            latheMesh.rotation.x = step += 0.01;

            // render using requestAnimationFrame
            requestAnimationFrame(render);
            webGLRenderer.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;
</script>
</body>
</html>