FBO/basic.html at master · nicoptere/FBO · GitHub

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<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title>FBO</title>
    <style>
        head, body{
            width:100%;
            height:100%;
            overflow: hidden;
            top:0;
            left:0;
            margin:0;
            padding:0;
        }
    </style>
</head>
<body>

    <script src="vendor/three.min.js"></script>
    <script src="ShaderLoader.js"></script>
    <script src="fbo.js"></script>

    <script>

        var scene, camera, renderer;

        window.onload = function() {

            var sl = new ShaderLoader();
            sl.loadShaders({
                simulation_vs : "",
                simulation_fs : "",
                render_vs : "",
                render_fs : ""
            }, "./glsl/basic/", init );

        };

        function init()
        {


            var w = window.innerWidth;
            var h = window.innerHeight;

            //regular scene creation
            scene = new THREE.Scene();
            camera = new THREE.PerspectiveCamera(60,w/h, 1,10000 );
            camera.position.z = 500;

            renderer = new THREE.WebGLRenderer();
            renderer.setSize( w,h );
            document.body.appendChild(renderer.domElement);

            //width / height of the FBO

            var width  = 256;
            var height = 256;

            //populate a Float32Array of random positions

            var data = getRandomData( width, height, 256 );
            var positions = new THREE.DataTexture( data, width, height, THREE.RGBFormat, THREE.FloatType );
            positions.needsUpdate = true;

            //this will be used to update the particles' positions

            var simulationShader = new THREE.ShaderMaterial({

                uniforms: {
                    positions: { type: "t", value: positions }
                },
                vertexShader: ShaderLoader.get( "simulation_vs" ),
                fragmentShader:  ShaderLoader.get( "simulation_fs" )
            });


            //this will be used to represent the particles on screen
            //note that 'positions' is a texture that will be set and updated during the FBO.update() call
            var renderShader = new THREE.ShaderMaterial( {
                uniforms: {
                    positions: { type: "t", value: null },
                    pointSize: { type: "f", value: 2 }
                },
                vertexShader: ShaderLoader.get( "render_vs" ),
                fragmentShader: ShaderLoader.get( "render_fs" ),
                transparent: true,
                blending:THREE.AdditiveBlending
            } );

            //init the FBO
            FBO.init( width,height, renderer, simulationShader, renderShader );
            scene.add( FBO.particles );

            //GO !
            window.addEventListener( "resize", onResize );
            onResize();
            update();

        }

        //returns an array of random 3D coordinates
        function getRandomData( width, height, size ){

            var len = width * height * 3;
            var data = new Float32Array( len );
            while( len-- )data[len] = ( Math.random() -.5 ) * size ;
            return data;
        }

        function onResize()
        {
            var w = window.innerWidth;
            var h = window.innerHeight;
            renderer.setSize(w,h);
            camera.aspect = w/h;
            camera.updateProjectionMatrix();
        }

        //update loop
        function update()
        {
            requestAnimationFrame(update);

            //update the simulation
            FBO.update();

            //update mesh
            FBO.particles.rotation.x += Math.PI / 180 * .5;
            FBO.particles.rotation.y -= Math.PI / 180 * .5;

            //render the particles at the new location
            renderer.render( scene, camera );

        }

    </script>

</body>
</html>