examples/webgl_lines_fat_raycasting.html

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		<title>three.js webgl - lines - fat</title>
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		<div id="container"></div>

		<div id="info"><a href="https://threejs.org" target="_blank">three.js</a> - fat lines raycasting</div>

		<script type="importmap">
			{
				"imports": {
					"three": "../build/three.module.js",
					"three/addons/": "./jsm/",
					"stats-gl": "https://cdn.jsdelivr.net/npm/stats-gl@3.6.0/dist/main.js"
				}
			}
		</script>

		<script type="module">

			import * as THREE from 'three';

			import Stats from 'stats-gl';

			import { GUI } from 'three/addons/libs/lil-gui.module.min.js';
			import { OrbitControls } from 'three/addons/controls/OrbitControls.js';
			import { LineMaterial } from 'three/addons/lines/LineMaterial.js';
			import { LineSegments2 } from 'three/addons/lines/LineSegments2.js';
			import { LineSegmentsGeometry } from 'three/addons/lines/LineSegmentsGeometry.js';
			import { Line2 } from 'three/addons/lines/Line2.js';
			import { LineGeometry } from 'three/addons/lines/LineGeometry.js';

			let line, thresholdLine, segments, thresholdSegments;
			let renderer, scene, camera, controls;
			let sphereInter, sphereOnLine;
			let stats;
			let gui;
			let clock;

			const color = new THREE.Color();

			const pointer = new THREE.Vector2( Infinity, Infinity );

			const raycaster = new THREE.Raycaster();

			raycaster.params.Line2 = {};
			raycaster.params.Line2.threshold = 0;

			const matLine = new LineMaterial( {

				color: 0xffffff,
				linewidth: 1, // in world units with size attenuation, pixels otherwise
				worldUnits: true,
				vertexColors: true,

				alphaToCoverage: true,

			} );

			const matThresholdLine = new LineMaterial( {

				color: 0xffffff,
				linewidth: matLine.linewidth, // in world units with size attenuation, pixels otherwise
				worldUnits: true,
				// vertexColors: true,
				transparent: true,
				opacity: 0.2,
				depthTest: false,
				visible: false,

			} );

			const params = {

				'line type': 0,
				'world units': matLine.worldUnits,
				'visualize threshold': matThresholdLine.visible,
				'width': matLine.linewidth,
				'alphaToCoverage': matLine.alphaToCoverage,
				'threshold': raycaster.params.Line2.threshold,
				'translation': raycaster.params.Line2.threshold,
				'animate': true

			};

			init();

			function init() {

				clock = new THREE.Clock();

				renderer = new THREE.WebGLRenderer( { antialias: true, alpha: true } );
				renderer.setPixelRatio( window.devicePixelRatio );
				renderer.setSize( window.innerWidth, window.innerHeight );
				renderer.setClearColor( 0x000000, 0.0 );
				renderer.setAnimationLoop( animate );
				document.body.appendChild( renderer.domElement );

				scene = new THREE.Scene();

				camera = new THREE.PerspectiveCamera( 40, window.innerWidth / window.innerHeight, 1, 1000 );
				camera.position.set( - 40, 0, 60 );

				controls = new OrbitControls( camera, renderer.domElement );
				controls.minDistance = 10;
				controls.maxDistance = 500;

				const sphereGeometry = new THREE.SphereGeometry( 0.25, 8, 4 );
				const sphereInterMaterial = new THREE.MeshBasicMaterial( { color: 0xff0000, depthTest: false } );
				const sphereOnLineMaterial = new THREE.MeshBasicMaterial( { color: 0x00ff00, depthTest: false } );

				sphereInter = new THREE.Mesh( sphereGeometry, sphereInterMaterial );
				sphereOnLine = new THREE.Mesh( sphereGeometry, sphereOnLineMaterial );
				sphereInter.visible = false;
				sphereOnLine.visible = false;
				sphereInter.renderOrder = 10;
				sphereOnLine.renderOrder = 10;
				scene.add( sphereInter );
				scene.add( sphereOnLine );

				// Position and THREE.Color Data

				const positions = [];
				const colors = [];
				const points = [];
				for ( let i = - 50; i < 50; i ++ ) {

					const t = i / 3;
					points.push( new THREE.Vector3( t * Math.sin( 2 * t ), t, t * Math.cos( 2 * t ) ) );

				}

				const spline = new THREE.CatmullRomCurve3( points );
				const divisions = Math.round( 3 * points.length );
				const point = new THREE.Vector3();
				const color = new THREE.Color();

				for ( let i = 0, l = divisions; i < l; i ++ ) {

					const t = i / l;

					spline.getPoint( t, point );
					positions.push( point.x, point.y, point.z );

					color.setHSL( t, 1.0, 0.5, THREE.SRGBColorSpace );
					colors.push( color.r, color.g, color.b );

				}

				const lineGeometry = new LineGeometry();
				lineGeometry.setPositions( positions );
				lineGeometry.setColors( colors );

				const segmentsGeometry = new LineSegmentsGeometry();
				segmentsGeometry.setPositions( positions );
				segmentsGeometry.setColors( colors );

				segments = new LineSegments2( segmentsGeometry, matLine );
				segments.computeLineDistances();
				segments.scale.set( 1, 1, 1 );
				scene.add( segments );
				segments.visible = false;

				thresholdSegments = new LineSegments2( segmentsGeometry, matThresholdLine );
				thresholdSegments.computeLineDistances();
				thresholdSegments.scale.set( 1, 1, 1 );
				scene.add( thresholdSegments );
				thresholdSegments.visible = false;

				line = new Line2( lineGeometry, matLine );
				line.computeLineDistances();
				line.scale.set( 1, 1, 1 );
				scene.add( line );

				thresholdLine = new Line2( lineGeometry, matThresholdLine );
				thresholdLine.computeLineDistances();
				thresholdLine.scale.set( 1, 1, 1 );
				scene.add( thresholdLine );

				const geo = new THREE.BufferGeometry();
				geo.setAttribute( 'position', new THREE.Float32BufferAttribute( positions, 3 ) );
				geo.setAttribute( 'color', new THREE.Float32BufferAttribute( colors, 3 ) );

				//

				document.addEventListener( 'pointermove', onPointerMove );
				window.addEventListener( 'resize', onWindowResize );
				onWindowResize();

				stats = new Stats( { horizontal: false, trackGPU: true } );
				stats.init( renderer );
				document.body.appendChild( stats.dom );
			
				initGui();

			}

			function onWindowResize() {

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

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

			}

			function onPointerMove( event ) {

				pointer.x = ( event.clientX / window.innerWidth ) * 2 - 1;
				pointer.y = - ( event.clientY / window.innerHeight ) * 2 + 1;

			}

			function animate() {

				const delta = clock.getDelta();

				const obj = line.visible ? line : segments;
				thresholdLine.position.copy( line.position );
				thresholdLine.quaternion.copy( line.quaternion );
				thresholdSegments.position.copy( segments.position );
				thresholdSegments.quaternion.copy( segments.quaternion );

				if ( params.animate ) {

					line.rotation.y += delta * 0.1;

					segments.rotation.y = line.rotation.y;

				}

				raycaster.setFromCamera( pointer, camera );

				const intersects = raycaster.intersectObject( obj );

				if ( intersects.length > 0 ) {

					sphereInter.visible = true;
					sphereOnLine.visible = true;

					sphereInter.position.copy( intersects[ 0 ].point );
					sphereOnLine.position.copy( intersects[ 0 ].pointOnLine );

					const index = intersects[ 0 ].faceIndex;
					const colors = obj.geometry.getAttribute( 'instanceColorStart' );

					color.fromBufferAttribute( colors, index );

					sphereInter.material.color.copy( color ).offsetHSL( 0.3, 0, 0 );
					sphereOnLine.material.color.copy( color ).offsetHSL( 0.7, 0, 0 );

					renderer.domElement.style.cursor = 'crosshair';

				} else {

					sphereInter.visible = false;
					sphereOnLine.visible = false;
					renderer.domElement.style.cursor = '';

				}

				renderer.render( scene, camera );

				stats.update();

			}

			//

			function switchLine( val ) {

				switch ( val ) {

					case 0:
						line.visible = true;
						thresholdLine.visible = true;

						segments.visible = false;
						thresholdSegments.visible = false;

						break;

					case 1:
						line.visible = false;
						thresholdLine.visible = false;

						segments.visible = true;
						thresholdSegments.visible = true;

						break;

				}

			}

			function initGui() {

				gui = new GUI();

				gui.add( params, 'line type', { 'LineGeometry': 0, 'LineSegmentsGeometry': 1 } ).onChange( function ( val ) {

					switchLine( val );

				} ).setValue( 1 );

				gui.add( params, 'world units' ).onChange( function ( val ) {

					matLine.worldUnits = val;
					matLine.needsUpdate = true;

					matThresholdLine.worldUnits = val;
					matThresholdLine.needsUpdate = true;

				} );

				gui.add( params, 'visualize threshold' ).onChange( function ( val ) {

					matThresholdLine.visible = val;

				} );

				gui.add( params, 'width', 1, 10 ).onChange( function ( val ) {

					matLine.linewidth = val;
					matThresholdLine.linewidth = matLine.linewidth + raycaster.params.Line2.threshold;

				} );

				gui.add( params, 'alphaToCoverage' ).onChange( function ( val ) {

					matLine.alphaToCoverage = val;

				} );

				gui.add( params, 'threshold', 0, 10 ).onChange( function ( val ) {

					raycaster.params.Line2.threshold = val;
					matThresholdLine.linewidth = matLine.linewidth + raycaster.params.Line2.threshold;

				} );

				gui.add( params, 'translation', 0, 10 ).onChange( function ( val ) {

					line.position.x = val;
					segments.position.x = val;

				} );

				gui.add( params, 'animate' );

			}

		</script>

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