Quick look into ThreeJS

This two last weeks were very exciting thanks to Adobe’s announcement : a new framework for 2D games : Starling, running on top of Stage3D (Molehill). Flash Player 11 is out henceforth, new 3D frameworks are coming : Adobe Proscenium, Aerys. And other big things like Unreal Engine 3 with Unreal Tournament 3 in our browser !

There’s a lot to digest ! Starling may be the next thing I will experiment…

Anyway, before all this annoucement, I was keeping an eye on JavaScript and its most awesome framework : ThreeJS created by Mr Doob. ThreeJS is a “lightweight 3D engine with a very low level of complexity — in other words, for dummies”. Dummy ? This is what I’m with 3D engine… in fact this is the first time that I try a 3D engine… so let’s start !

The three.js repository is on github with code source and many examples.
I started to learn ThreeJS with Ilmari Heikkinen’s slides that you can find here. It is really a good way to start.

Click here to see my experimentation.

I used three.js with WebGL render. My source code :

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<html>
    <head>
        <meta http-equiv="content-type" content="text/html; charset=utf-8"/> 
        <title>three.js</title>
        <style type="text/css"> 
            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>
        <div id="info"><a href="http://github.com/mrdoob/three.js" target="_blank">three.js</a></div>
 
        <script type="text/javascript" src="Three.js"></script>
        <script type="text/javascript" src="raf.js"></script>
 
        <script type="text/javascript">
 
            var renderer = new THREE.WebGLRenderer({antialias: true});
            renderer.setSize(document.body.clientWidth, document.body.clientHeight);
 
            document.body.appendChild(renderer.domElement);
 
            renderer.setClearColorHex(0xEEEEEE, 1.0);
            renderer.clear();
            renderer.shadowCameraFov = 50;
            renderer.shadowMapWidth = 1024;;
            renderer.shadowMapHeight = 1024;
 
 
            var fov = 45; // camera field-of-view in degrees
            var width = renderer.domElement.width;
            var height = renderer.domElement.height;
            var aspect = width / height; // view aspect ratio
            var near = 1; // near clip plane
            var far = 10000; // far clip plane
            var camera = new THREE.Camera(fov, aspect, near, far);
            camera.position.z = -400;
            camera.position.x = 200;
            camera.position.y = 350;
 
            const NBR_ELEMENTS = 250;
 
            var scene = new THREE.Scene();  
 
            var light = new THREE.SpotLight();
            light.castShadow = true;
            light.position.set( 170, 330, -160 );
            scene.addLight(light);
 
            var tab = [];
            var sprite;
 
            for (var i = 0; i < NBR_ELEMENTS; ++i) {
                sprite = new THREE.Mesh(new THREE.CubeGeometry(25, 25, 25), new THREE.MeshLambertMaterial({color: Math.random() * 0xffffff}));
                sprite.castShadow = true;
                scene.addChild(sprite);
                if (i == 0)
                    sprite.position.x = Math.random() * 1000;
                else
                    sprite.position.x = (Math.random() > 0.5) ? Math.random() * 1000 : -Math.random() * 1000;
                sprite.position.y = (Math.random() > 0.5) ? Math.random() * 1000 : -Math.random() * 1000;
                sprite.position.z = (Math.random() > 0.5) ? Math.random() * 1000 : -Math.random() * 1000;
                tab.push(sprite);
            }
 
            var oneElement = false;
 
            var diffx;
            var diffy;
            var diffz;
 
            var i = 0;
 
            renderer.shadowMapEnabled = true;
 
            renderer.render(scene, camera);
 
            var paused = false;
            var last = new Date().getTime();
            var down = false;
            var sx = 0, sy = 0;
            window.onmousedown = function (ev){
                down = true; sx = ev.clientX; sy = ev.clientY;
            };
            window.onmouseup = function(){ down = false; };
            window.onmousemove = function(ev) {
                if (down) {
                    var dx = ev.clientX - sx;
                    var dy = ev.clientY - sy;
                    camera.position.x += dx;
                    camera.position.y += dy;
                    sx += dx;
                    sy += dy;
                }
            }
            function animate(t) {
                if (!paused) {
 
                     /*last = t;
 
                    sphere.position.x = Math.cos(t/600)*300;
                    sphere.position.z = Math.sin(t/600)*300;
                    sphere.rotation.y = t/800;*/
 
                    if (oneElement) {
 
                        if (tab[0].position.x < 1000) {
 
                            i = 0;
 
                            while (i < NBR_ELEMENTS) {
 
                                diffx = 0 - tab[i].position.x;
                                diffy = 0 - tab[i].position.y;
                                diffz = 0 - tab[i].position.z;
 
                                tab[i].position.x -= diffx * 0.05;
                                tab[i].position.y -= diffy * 0.05; 
                                tab[i].position.z -= diffz * 0.05;
 
                                ++i;
                            }
 
                        } else {
                            oneElement = false;
                        }
 
                    } else {
 
                        if (tab[0].position.x > 1) {
 
                            i = 0; 
 
                            while (i < NBR_ELEMENTS) {
 
                                diffx = 0 - tab[i].position.x;
                                diffy = 0 - tab[i].position.y;
                                diffz = 0 - tab[i].position.z;
 
                                tab[i].position.x += diffx * 0.05;
                                tab[i].position.y += diffy * 0.05; 
                                tab[i].position.z += diffz * 0.05;
                                ++i;
                            }
 
                        } else {
                            oneElement = true;
 
                        }
 
                    }
 
                    renderer.clear();
                    renderer.render(scene, camera);
                }
                window.requestAnimationFrame(animate, renderer.domElement);
            };
            animate(new Date().getTime());
            onmessage = function(ev) {
                paused = (ev.data == 'pause');
            };
        </script>
 
    </body>
</html>

I used raf.js to make an “enter frame” on the page, you can find the script on Ilmari Heikkinen’s repository.

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