<!DOCTYPE html>
<html lang="en">
<head>
<title>three.js webgl - cameras - logarithmic depth buffer</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: #000;
margin: 0px;
overflow: hidden;
}
#info {
position: absolute;
top: 0px; width: 100%;
padding: 5px;
z-index: 100;
color: #ddd;
text-shadow: 0 0 1px rgba(0,0,0,1);
}
a {
color: #0080ff;
}
b { color: lightgreen }
#stats { position: absolute; top:0; left: 0 }
.renderer_label {
position: absolute;
bottom: 1em;
width: 100%;
color: white;
z-index: 10;
display: block;
text-align: center;
}
.renderer_label.renderer_label_normal {
}
.renderer_label.renderer_label_logzbuf {
}
#container {
white-space: nowrap;
}
#container_normal {
width: 50%;
display: inline-block;
position: relative;
overflow: hidden;
}
#container_logzbuf {
width: 50%;
display: inline-block;
position: relative;
overflow: hidden;
}
#renderer_border {
position: absolute;
top: 0;
bottom: 0;
width: 2px;
z-index: 10;
opacity: .8;
background: #ccc;
border: 1px inset #ccc;
cursor: col-resize;
}
</style>
</head>
<body>
<div id="container">
<div id="container_normal"><h2 class="renderer_label renderer_label_normal">normal z-buffer</h2></div><div id="container_logzbuf"><h2 class="renderer_label renderer_label_logzbuf">logarithmic z-buffer</h2></div>
<div id="renderer_border"></div>
</div>
<div id="info">
<a href="http://threejs.org" target="_blank">three.js</a> - cameras - logarithmic depth buffer<br/>
Zoom through scene with objects ranging in size from 1µm to 100,000,000 light years using the mousewheel<br/>
Linear z-buffer handles close-up objects well, but fails spectacularly at distant objects<br/>
Logarithmic handles all but the smallest objects with ease
</div>
<script src="../build/three.min.js"></script>
<script src="js/libs/stats.min.js"></script>
<script src="fonts/helvetiker_regular.typeface.js"></script>
<script>
// 1 micrometer to 100 billion light years in one scene, with 1 unit = 1 meter? preposterous! and yet...
var NEAR = 1e-6, FAR = 1e27;
var SCREEN_WIDTH = window.innerWidth;
var SCREEN_HEIGHT = window.innerHeight;
var screensplit = .25, screensplit_right = 0;
var mouse = [.5, .5];
var zoompos = -100, minzoomspeed = .015;
var zoomspeed = minzoomspeed;
var container, stats;
var objects = {};
// Generate a number of text labels, from 1µm in size up to 100,000,000 light years
// Try to use some descriptive real-world examples of objects at each scale
var labeldata = [
{ size: .01, scale: .001, label: "microscopic (1µm)", scale: .0001 }, // FIXME - triangulating text fails at this size, so we scale instead
{ size: .01, scale: 0.1, label: "minuscule (1mm)", scale: .1},
{ size: .01, scale: 1.0, label: "tiny (1cm)", scale: 1 },
{ size: 1, scale: 1.0, label: "child-sized (1m)", scale: 1 },
{ size: 10, scale: 1.0, label: "tree-sized (10m)", scale: 1 },
{ size: 100, scale: 1.0, label: "building-sized (100m)", scale: 1 },
{ size: 1000, scale: 1.0, label: "medium (1km)", scale: 1 },
{ size: 10000, scale: 1.0, label: "city-sized (10km)", scale: 1 },
{ size: 3400000, scale: 1.0, label: "moon-sized (3,400 Km)", scale: 1 },
{ size: 12000000, scale: 1.0, label: "planet-sized (12,000 km)", scale: 1 },
{ size: 1400000000, scale: 1.0, label: "sun-sized (1,400,000 km)", scale: 1 },
{ size: 7.47e12, scale: 1.0, label: "solar system-sized (50Au)", scale: 1 },
{ size: 9.4605284e15, scale: 1.0, label: "gargantuan (1 light year)", scale: 1 },
{ size: 3.08567758e16, scale: 1.0, label: "ludicrous (1 parsec)", scale: 1 },
{ size: 1e19, scale: 1.0, label: "mind boggling (1000 light years)", scale: 1 },
{ size: 1.135e21, scale: 1.0, label: "galaxy-sized (120,000 light years)", scale: 1 },
{ size: 9.46e23, scale: 1.0, label: "... (100,000,000 light years)", scale: 1 }
];
init();
animate();
function init() {
container = document.getElementById( 'container' );
// Initialize two copies of the same scene, one with normal z-buffer and one with logarithmic z-buffer
objects.normal = initScene('normal', false);
objects.logzbuf = initScene('logzbuf', true);
stats = new Stats();
container.appendChild(stats.domElement);
// Resize border allows the user to easily compare effects of logarithmic depth buffer over the whole scene
border = document.getElementById( 'renderer_border' );
border.addEventListener("mousedown", onBorderMouseDown);
window.addEventListener( 'resize', onWindowResize, false );
window.addEventListener( 'mousewheel', onMouseWheel, false );
window.addEventListener( 'DOMMouseScroll', onMouseWheel, false );
window.addEventListener( 'mousemove', onMouseMove, false );
render();
}
function initScene(name, logDepthBuf) {
var scene = new THREE.Scene();
var framecontainer = document.getElementById('container_' + name);
var camera = new THREE.PerspectiveCamera( 50, screensplit * SCREEN_WIDTH / SCREEN_HEIGHT, NEAR, FAR );
scene.add(camera);
var light = new THREE.DirectionalLight(0xffffff, 1);
light.position.set(100,100,100);
scene.add(light);
var materialargs = {
color: 0xffffff,
specular: 0xffaa00,
shininess: 50,
shading: THREE.SmoothShading,
emissive: 0x000000
};
var geomtransform = new THREE.Matrix4();
var tmpvec = new THREE.Vector3();
var meshes = [];
var coloroffset = 0;
var colorskip = ['black', 'antiquewhite', 'bisque', 'beige', 'blanchedalmond', 'darkblue', 'darkcyan'];
var colorkeys = Object.keys( THREE.ColorKeywords );
for (var i = 0; i < labeldata.length; i++) {
var scale = labeldata[i].scale || 1;
var labelgeo = new THREE.TextGeometry( labeldata[i].label, {
size: labeldata[i].size,
height: labeldata[i].size / 2,
font: 'helvetiker',
});
labelgeo.computeBoundingSphere();
// center text
geomtransform.setPosition( tmpvec.set( -labelgeo.boundingSphere.radius, 0, 0 ) );
labelgeo.applyMatrix( geomtransform );
// Pick a color at "random". Exclude black, because it looks bad.
while ( colorskip.indexOf( colorkeys[ i + coloroffset ] ) != -1 ) {
coloroffset++;
}
materialargs.color = THREE.ColorKeywords[ colorkeys[ i + coloroffset ] ];
var material = new THREE.MeshPhongMaterial( materialargs );
var textmesh = new THREE.Mesh( labelgeo, material );
textmesh.scale.set(scale, scale, scale);
textmesh.position.z = -labeldata[i].size * scale;
textmesh.position.y = labeldata[i].size / 4 * scale;
textmesh.updateMatrix();
var dotmesh = new THREE.Mesh(new THREE.SphereGeometry(labeldata[i].size * scale / 2, 24, 12), material);
dotmesh.position.y = -labeldata[i].size / 4 * scale;
dotmesh.updateMatrix();
var merged = new THREE.Geometry();
merged.merge( textmesh.geometry, textmesh.matrix );
merged.merge( dotmesh.geometry, dotmesh.matrix );
var mesh = new THREE.Mesh(merged, material);
mesh.position.z = -labeldata[i].size * 1 * scale;
scene.add(mesh);
}
var renderer = new THREE.WebGLRenderer({ antialias: true, logarithmicDepthBuffer: logDepthBuf });
renderer.setPixelRatio( window.devicePixelRatio );
renderer.setSize(SCREEN_WIDTH/2, SCREEN_HEIGHT);
renderer.domElement.style.position = "relative";
renderer.domElement.id = 'renderer_' + name;
framecontainer.appendChild(renderer.domElement);
return { container: framecontainer, renderer: renderer, scene: scene, camera: camera }
}
function updateRendererSizes() {
// Recalculate size for both renderers when screen size or split location changes
SCREEN_WIDTH = window.innerWidth;
SCREEN_HEIGHT = window.innerHeight;
screensplit_right = 1 - screensplit;
objects.normal.renderer.setSize( screensplit * SCREEN_WIDTH, SCREEN_HEIGHT );
objects.normal.camera.aspect = screensplit * SCREEN_WIDTH / SCREEN_HEIGHT;
objects.normal.camera.updateProjectionMatrix();
objects.normal.camera.setViewOffset( SCREEN_WIDTH, SCREEN_HEIGHT, 0, 0, SCREEN_WIDTH * screensplit, SCREEN_HEIGHT );
objects.normal.container.style.width = (screensplit * 100) + '%';
objects.logzbuf.renderer.setSize( screensplit_right * SCREEN_WIDTH, SCREEN_HEIGHT );
objects.logzbuf.camera.aspect = screensplit_right * SCREEN_WIDTH / SCREEN_HEIGHT;
objects.logzbuf.camera.updateProjectionMatrix();
objects.logzbuf.camera.setViewOffset( SCREEN_WIDTH, SCREEN_HEIGHT, SCREEN_WIDTH * screensplit, 0, SCREEN_WIDTH * screensplit_right, SCREEN_HEIGHT );
objects.logzbuf.container.style.width = (screensplit_right * 100) + '%';
border.style.left = (screensplit * 100) + "%";
}
function animate() {
requestAnimationFrame( animate );
render();
}
function render() {
// Put some limits on zooming
var minzoom = labeldata[0].size * labeldata[0].scale*1;
var maxzoom = labeldata[labeldata.length-1].size * labeldata[labeldata.length-1].scale * 100;
var damping = (Math.abs(zoomspeed) > minzoomspeed ? .95 : 1.0);
// Zoom out faster the further out you go
var zoom = THREE.Math.clamp(Math.pow(Math.E, zoompos), minzoom, maxzoom);
zoompos = Math.log(zoom);
// Slow down quickly at the zoom limits
if ((zoom == minzoom && zoomspeed < 0) || (zoom == maxzoom && zoomspeed > 0)) {
damping = .85;
}
zoompos += zoomspeed;
zoomspeed *= damping;
objects.normal.camera.position.x = Math.sin(.5 * Math.PI * (mouse[0] - .5)) * zoom;
objects.normal.camera.position.y = Math.sin(.25 * Math.PI * (mouse[1] - .5)) * zoom;
objects.normal.camera.position.z = Math.cos(.5 * Math.PI * (mouse[0] - .5)) * zoom;
objects.normal.camera.lookAt(objects.normal.scene.position);
// Clone camera settings across both scenes
objects.logzbuf.camera.position.copy(objects.normal.camera.position);
objects.logzbuf.camera.quaternion.copy(objects.normal.camera.quaternion);
// Update renderer sizes if the split has changed
if (screensplit_right != 1 - screensplit) {
updateRendererSizes();
}
objects.normal.renderer.render(objects.normal.scene, objects.normal.camera);
objects.logzbuf.renderer.render(objects.logzbuf.scene, objects.logzbuf.camera);
stats.update();
}
function onWindowResize(event) {
updateRendererSizes();
}
function onBorderMouseDown(ev) {
// activate draggable window resizing bar
window.addEventListener("mousemove", onBorderMouseMove);
window.addEventListener("mouseup", onBorderMouseUp);
ev.stopPropagation();
ev.preventDefault();
}
function onBorderMouseMove(ev) {
screensplit = Math.max(0, Math.min(1, ev.clientX / window.innerWidth));
ev.stopPropagation();
}
function onBorderMouseUp(ev) {
window.removeEventListener("mousemove", onBorderMouseMove);
window.removeEventListener("mouseup", onBorderMouseUp);
}
function onMouseMove(ev) {
mouse[0] = ev.clientX / window.innerWidth;
mouse[1] = ev.clientY / window.innerHeight;
}
function onMouseWheel(ev) {
var amount = -ev.wheelDeltaY || ev.detail;
var dir = amount / Math.abs(amount);
zoomspeed = dir/10;
// Slow down default zoom speed after user starts zooming, to give them more control
minzoomspeed = 0.001;
}
</script>
</body>
</html>