examples/webgl_clipping.html

<!DOCTYPE html>
<html lang="en">
	<head>
		<title>three.js webgl - clipping planes</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 {
				margin: 0px;
				background-color: #000000;
				overflow: hidden;
			}
		</style>
	</head>
	<body>

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

		<script src="js/libs/dat.gui.min.js"></script>

		<script>

			var camera, scene, renderer, startTime, object;

			function init() {

				camera = new THREE.PerspectiveCamera(
						36, window.innerWidth / window.innerHeight, 0.25, 16 );

				camera.position.set( 0, 1.3, 3 );

				scene = new THREE.Scene();

				// Lights

				scene.add( new THREE.AmbientLight( 0x505050 ) );

				var spotLight = new THREE.SpotLight( 0xffffff );
				spotLight.angle = Math.PI / 5;
				spotLight.penumbra = 0.2;
				spotLight.position.set( 2, 3, 3 );
				spotLight.castShadow = true;
				spotLight.shadow.camera.near = 3;
				spotLight.shadow.camera.far = 10;
				spotLight.shadow.mapSize.width = 1024;
				spotLight.shadow.mapSize.height = 1024;
				scene.add( spotLight );

				var dirLight = new THREE.DirectionalLight( 0x55505a, 1 );
				dirLight.position.set( 0, 3, 0 );
				dirLight.castShadow = true;
				dirLight.shadow.camera.near = 1;
				dirLight.shadow.camera.far = 10;

				dirLight.shadow.camera.right = 1;
				dirLight.shadow.camera.left = - 1;
				dirLight.shadow.camera.top	= 1;
				dirLight.shadow.camera.bottom = - 1;

				dirLight.shadow.mapSize.width = 1024;
				dirLight.shadow.mapSize.height = 1024;
				scene.add( dirLight );

				// ***** Clipping planes: *****

				var localPlane = new THREE.Plane( new THREE.Vector3( 0, - 1, 0 ), 0.8 ),
					globalPlane = new THREE.Plane( new THREE.Vector3( - 1, 0, 0 ), 0.1 );

				// Geometry

				var material = new THREE.MeshPhongMaterial( {
						color: 0x80ee10,
						shininess: 100,
						side: THREE.DoubleSide,

						// ***** Clipping setup (material): *****
						clippingPlanes: [ localPlane ],
						clipShadows: true

					} ),

					geometry = new THREE.TorusKnotGeometry( 0.4, 0.08, 95, 20 );

				object = new THREE.Mesh( geometry, material );
				object.castShadow = true;
				scene.add( object );

				var ground = new THREE.Mesh(
						new THREE.PlaneBufferGeometry( 9, 9, 1, 1 ),
						new THREE.MeshPhongMaterial( {
							color: 0xa0adaf, shininess: 150 } ) );

				ground.rotation.x = - Math.PI / 2; // rotates X/Y to X/Z
				ground.receiveShadow = true;
				scene.add( ground );

				// Renderer

				renderer = new THREE.WebGLRenderer();
				renderer.shadowMap.enabled = true;
				renderer.setPixelRatio( window.devicePixelRatio );
				renderer.setSize( window.innerWidth, window.innerHeight );
				window.addEventListener( 'resize', onWindowResize, false );
				document.body.appendChild( renderer.domElement );

				// ***** Clipping setup (renderer): *****
				var globalPlanes = [ globalPlane ],
					Empty = Object.freeze( [] );
				renderer.clippingPlanes = Empty; // GUI sets it to globalPlanes
				renderer.localClippingEnabled = true;

				// Controls

				var controls = new THREE.OrbitControls( camera, renderer.domElement );
				controls.target.set( 0, 1, 0 );
				controls.update();

				// GUI

				var gui = new dat.GUI(),
					folderLocal = gui.addFolder( "Local Clipping" ),
					propsLocal = {

						get 'Enabled'() { return renderer.localClippingEnabled; },
						set 'Enabled'( v ) { renderer.localClippingEnabled = v; },

						get 'Shadows'() { return material.clipShadows; },
						set 'Shadows'( v ) { material.clipShadows = v; },

						get 'Plane'() { return localPlane.constant; },
						set 'Plane'( v ) { localPlane.constant = v }

					},

					folderGlobal = gui.addFolder( "Global Clipping" ),
					propsGlobal = {

						get 'Enabled'() { return renderer.clippingPlanes !== Empty; },
						set 'Enabled'( v  ) {
								renderer.clippingPlanes = v ? globalPlanes : Empty; },

						get 'Plane'() { return globalPlane.constant; },
						set 'Plane'( v ) { globalPlane.constant = v; }

					};

				folderLocal.add( propsLocal, 'Enabled' );
				folderLocal.add( propsLocal, 'Shadows' );
				folderLocal.add( propsLocal, 'Plane', 0.3, 1.25 );

				folderGlobal.add( propsGlobal, 'Enabled' );
				folderGlobal.add( propsGlobal, 'Plane', -0.4, 3 );

				// Start

				startTime = Date.now();

			}

			function onWindowResize() {

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

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

			}

			function animate() {

				var currentTime = Date.now(),
					time = ( currentTime - startTime ) / 1000;

				requestAnimationFrame( animate );

				object.position.y = 0.8;
				object.rotation.x = time * 0.5;
				object.rotation.y = time * 0.2;
				object.scale.setScalar( Math.cos( time ) * 0.125 + 0.875 );

				renderer.render( scene, camera );

			}

			init();
			animate();

		</script>

	</body>
</html>