examples/webgl_depth_texture.html

<!DOCTYPE html>
<html lang="en">
	<head>
		<title>three.js webgl - Depth Texture</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: #fff;
				font-family:Monospace;
				font-size:13px;
				text-align:center;
				background-color: #000;
				margin: 0px;
				overflow: hidden;
			}
			a {
				color: #B2E9FF;
				font-weight: bold;
				pointer-events: auto;
			}

			canvas {
				position: absolute;
				top: 0;
				left: 0;
			}

			#info {
				pointer-events: none;
				position: absolute;
				left: 0;
				top: 0px; width: 100%;
				padding: 5px;
				display: inline-block;
			}

			#error {
				margin: auto;
				margin-top: 40px;
				display: block;
				max-width: 400px;
				padding: 20px;
				background: #CE0808;
			}
		</style>

		<script id="post-vert" type="x-shader/x-vertex">
			varying vec2 vUv;

			void main() {
				vUv = uv;
				gl_Position = projectionMatrix * modelViewMatrix * vec4(position, 1.0);
			}
		</script>
		<script id="post-frag" type="x-shader/x-fragment">
			#include <packing>

			varying vec2 vUv;
			uniform sampler2D tDiffuse;
			uniform sampler2D tDepth;
			uniform float cameraNear;
			uniform float cameraFar;


			float readDepth( sampler2D depthSampler, vec2 coord ) {
				float fragCoordZ = texture2D( depthSampler, coord ).x;
				float viewZ = perspectiveDepthToViewZ( fragCoordZ, cameraNear, cameraFar );
				return viewZToOrthographicDepth( viewZ, cameraNear, cameraFar );
			}

			void main() {
				//vec3 diffuse = texture2D( tDiffuse, vUv ).rgb;
				float depth = readDepth( tDepth, vUv );

				gl_FragColor.rgb = 1.0 - vec3( depth );
				gl_FragColor.a = 1.0;
			}
		</script>

	</head>
	<body>
		<canvas></canvas>
		<div id="info">
			<a href="http://threejs.org" target="_blank" rel="noopener">threejs</a> - WebGL - Depth Texture<br/>
			Stores render target depth in a texture attachment.<br/>
			Created by <a href="http://twitter.com/mattdesl" target="_blank" rel="noopener">@mattdesl</a>.

			<div id="error" style="display: none;">
			Your browser does not support <strong>WEBGL_depth_texture</strong>.<br/><br/>
			This demo will not work.
			</div>
		</div>

		<script src="../build/three.js"></script>
		<script src="js/controls/OrbitControls.js"></script>
		<script src="js/libs/stats.min.js"></script>

		<script>

			var camera, scene, renderer, stats;
			var target;
			var postScene, postCamera;
			var supportsExtension = true;

			init();
			animate();

			function init() {

				renderer = new THREE.WebGLRenderer( { canvas: document.querySelector( 'canvas' ) } );

				if ( ! renderer.extensions.get( 'WEBGL_depth_texture' ) ) {

					supportsExtension = false;
					document.querySelector( '#error' ).style.display = 'block';
					return;

				}

				renderer.setPixelRatio( window.devicePixelRatio );
				renderer.setSize( window.innerWidth, window.innerHeight );

				//

				stats = new Stats();
				document.body.appendChild( stats.dom );

				camera = new THREE.PerspectiveCamera( 70, window.innerWidth / window.innerHeight, 0.01, 50 );
				camera.position.z = 4;

				var controls = new THREE.OrbitControls( camera, renderer.domElement );
				controls.enableDamping = true;
				controls.dampingFactor = 0.25;
				controls.rotateSpeed = 0.35;

				// Create a multi render target with Float buffers
				target = new THREE.WebGLRenderTarget( window.innerWidth, window.innerHeight );
				target.texture.format = THREE.RGBFormat;
				target.texture.minFilter = THREE.NearestFilter;
				target.texture.magFilter = THREE.NearestFilter;
				target.texture.generateMipmaps = false;
				target.stencilBuffer = false;
				target.depthBuffer = true;
				target.depthTexture = new THREE.DepthTexture();
				target.depthTexture.type = THREE.UnsignedShortType;

				// Our scene
				scene = new THREE.Scene();
				setupScene();

				// Setup post-processing step
				setupPost();

				onWindowResize();
				window.addEventListener( 'resize', onWindowResize, false );

			}

			function setupPost() {

				// Setup post processing stage
				postCamera = new THREE.OrthographicCamera( - 1, 1, 1, - 1, 0, 1 );
				var postMaterial = new THREE.ShaderMaterial( {
					vertexShader: document.querySelector( '#post-vert' ).textContent.trim(),
					fragmentShader: document.querySelector( '#post-frag' ).textContent.trim(),
					uniforms: {
						cameraNear: { value: camera.near },
						cameraFar: { value: camera.far },
						tDiffuse: { value: target.texture },
						tDepth: { value: target.depthTexture }
					}
				} );
				var postPlane = new THREE.PlaneBufferGeometry( 2, 2 );
				var postQuad = new THREE.Mesh( postPlane, postMaterial );
				postScene = new THREE.Scene();
				postScene.add( postQuad );

			}

			function setupScene() {

				//var diffuse = new THREE.TextureLoader().load( 'textures/brick_diffuse.jpg' );
				//diffuse.wrapS = diffuse.wrapT = THREE.RepeatWrapping;

				// Setup some geometries
				var geometry = new THREE.TorusKnotBufferGeometry( 1, 0.3, 128, 64 );
				var material = new THREE.MeshBasicMaterial( { color: 'blue' } );

				var count = 50;
				var scale = 5;

				for ( var i = 0; i < count; i ++ ) {

					var r = Math.random() * 2.0 * Math.PI;
					var z = ( Math.random() * 2.0 ) - 1.0;
					var zScale = Math.sqrt( 1.0 - z * z ) * scale;

					var mesh = new THREE.Mesh( geometry, material );
					mesh.position.set(
						Math.cos( r ) * zScale,
						Math.sin( r ) * zScale,
						z * scale
					);
					mesh.rotation.set( Math.random(), Math.random(), Math.random() );
					scene.add( mesh );

				}

			}

			function onWindowResize() {

				var aspect = window.innerWidth / window.innerHeight;
				camera.aspect = aspect;
				camera.updateProjectionMatrix();

				var dpr = renderer.getPixelRatio();
				target.setSize( window.innerWidth * dpr, window.innerHeight * dpr );
				renderer.setSize( window.innerWidth, window.innerHeight );

			}

			function animate() {

				if ( ! supportsExtension ) return;

				requestAnimationFrame( animate );

				// render scene into target
				renderer.setRenderTarget( target );
				renderer.render( scene, camera );

				// render post FX
				renderer.setRenderTarget( null );
				renderer.render( postScene, postCamera );

				stats.update();

			}

		</script>

	</body>
</html>