examples/webgl_custom_attributes_points3.html

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		<title>three.js webgl - custom attributes [particles][billboards][alphatest]</title>
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		<div id="info"><a href="https://threejs.org" target="_blank" rel="noopener">three.js</a> - custom attributes example - billboards - alphatest</div>
		<div id="container"></div>

		<script type="x-shader/x-vertex" id="vertexshader">

			attribute float size;
			attribute vec4 ca;

			varying vec4 vColor;

			void main() {

				vColor = ca;

				vec4 mvPosition = modelViewMatrix * vec4( position, 1.0 );

				gl_PointSize = size * ( 150.0 / -mvPosition.z );

				gl_Position = projectionMatrix * mvPosition;

			}

		</script>

		<script type="x-shader/x-fragment" id="fragmentshader">

			uniform vec3 color;
			uniform sampler2D pointTexture;

			varying vec4 vColor;

			void main() {

				vec4 outColor = texture2D( pointTexture, gl_PointCoord );

				if ( outColor.a < 0.5 ) discard;

				gl_FragColor = outColor * vec4( color * vColor.xyz, 1.0 );

				float depth = gl_FragCoord.z / gl_FragCoord.w;
				const vec3 fogColor = vec3( 0.0 );

				float fogFactor = smoothstep( 200.0, 600.0, depth );
				gl_FragColor = mix( gl_FragColor, vec4( fogColor, gl_FragColor.w ), fogFactor );

			}

		</script>

		<script type="importmap">
			{
				"imports": {
					"three": "../build/three.module.js",
					"three/addons/": "./jsm/"
				}
			}
		</script>

		<script type="module">

			import * as THREE from 'three';

			import Stats from 'three/addons/libs/stats.module.js';

			import * as BufferGeometryUtils from 'three/addons/utils/BufferGeometryUtils.js';

			let renderer, scene, camera, stats;

			let object;

			let vertices1;

			const WIDTH = window.innerWidth;
			const HEIGHT = window.innerHeight;

			init();

			function init() {

				camera = new THREE.PerspectiveCamera( 40, WIDTH / HEIGHT, 1, 1000 );
				camera.position.z = 500;

				scene = new THREE.Scene();

				let radius = 100;
				const inner = 0.6 * radius;
				const vertex = new THREE.Vector3();
				const vertices = [];

				for ( let i = 0; i < 100000; i ++ ) {

					vertex.x = Math.random() * 2 - 1;
					vertex.y = Math.random() * 2 - 1;
					vertex.z = Math.random() * 2 - 1;
					vertex.multiplyScalar( radius );

					if ( ( vertex.x > inner || vertex.x < - inner ) ||
						( vertex.y > inner || vertex.y < - inner ) ||
						( vertex.z > inner || vertex.z < - inner ) )

						vertices.push( vertex.x, vertex.y, vertex.z );

				}

				vertices1 = vertices.length / 3;

				radius = 200;

				let boxGeometry1 = new THREE.BoxGeometry( radius, 0.1 * radius, 0.1 * radius, 50, 5, 5 );

				// if normal and uv attributes are not removed, mergeVertices() can't consolidate identical vertices with different normal/uv data

				boxGeometry1.deleteAttribute( 'normal' );
				boxGeometry1.deleteAttribute( 'uv' );

				boxGeometry1 = BufferGeometryUtils.mergeVertices( boxGeometry1 );

				const matrix = new THREE.Matrix4();
				const position = new THREE.Vector3();
				const rotation = new THREE.Euler();
				const quaternion = new THREE.Quaternion();
				const scale = new THREE.Vector3( 1, 1, 1 );

				function addGeo( geo, x, y, z, ry ) {

					position.set( x, y, z );
					rotation.set( 0, ry, 0 );

					matrix.compose( position, quaternion.setFromEuler( rotation ), scale );

					const positionAttribute = geo.getAttribute( 'position' );

					for ( let i = 0, l = positionAttribute.count; i < l; i ++ ) {

						vertex.fromBufferAttribute( positionAttribute, i );
						vertex.applyMatrix4( matrix );
						vertices.push( vertex.x, vertex.y, vertex.z );

					}

				}

				// side 1

				addGeo( boxGeometry1, 0, 110, 110, 0 );
				addGeo( boxGeometry1, 0, 110, - 110, 0 );
				addGeo( boxGeometry1, 0, - 110, 110, 0 );
				addGeo( boxGeometry1, 0, - 110, - 110, 0 );

				// side 2

				addGeo( boxGeometry1, 110, 110, 0, Math.PI / 2 );
				addGeo( boxGeometry1, 110, - 110, 0, Math.PI / 2 );
				addGeo( boxGeometry1, - 110, 110, 0, Math.PI / 2 );
				addGeo( boxGeometry1, - 110, - 110, 0, Math.PI / 2 );

				// corner edges

				let boxGeometry2 = new THREE.BoxGeometry( 0.1 * radius, radius * 1.2, 0.1 * radius, 5, 60, 5 );

				boxGeometry2.deleteAttribute( 'normal' );
				boxGeometry2.deleteAttribute( 'uv' );

				boxGeometry2 = BufferGeometryUtils.mergeVertices( boxGeometry2 );

				addGeo( boxGeometry2, 110, 0, 110, 0 );
				addGeo( boxGeometry2, 110, 0, - 110, 0 );
				addGeo( boxGeometry2, - 110, 0, 110, 0 );
				addGeo( boxGeometry2, - 110, 0, - 110, 0 );

				const positionAttribute = new THREE.Float32BufferAttribute( vertices, 3 );

				const colors = [];
				const sizes = [];

				const color = new THREE.Color();

				for ( let i = 0; i < positionAttribute.count; i ++ ) {

					if ( i < vertices1 ) {

						color.setHSL( 0.5 + 0.2 * ( i / vertices1 ), 1, 0.5 );

					} else {

						color.setHSL( 0.1, 1, 0.5 );

					}

					color.toArray( colors, i * 3 );

					sizes[ i ] = i < vertices1 ? 10 : 40;

				}

				const geometry = new THREE.BufferGeometry();
				geometry.setAttribute( 'position', positionAttribute );
				geometry.setAttribute( 'ca', new THREE.Float32BufferAttribute( colors, 3 ) );
				geometry.setAttribute( 'size', new THREE.Float32BufferAttribute( sizes, 1 ) );

				//

				const texture = new THREE.TextureLoader().load( 'textures/sprites/ball.png' );
				texture.wrapS = THREE.RepeatWrapping;
				texture.wrapT = THREE.RepeatWrapping;

				const material = new THREE.ShaderMaterial( {

					uniforms: {
						amplitude: { value: 1.0 },
						color: { value: new THREE.Color( 0xffffff ) },
						pointTexture: { value: texture }
					},
					vertexShader: document.getElementById( 'vertexshader' ).textContent,
					fragmentShader: document.getElementById( 'fragmentshader' ).textContent

				} );

				//

				object = new THREE.Points( geometry, material );
				scene.add( object );

				//

				renderer = new THREE.WebGLRenderer();
				renderer.setPixelRatio( window.devicePixelRatio );
				renderer.setSize( WIDTH, HEIGHT );
				renderer.setAnimationLoop( animate );

				const container = document.getElementById( 'container' );
				container.appendChild( renderer.domElement );

				stats = new Stats();
				container.appendChild( stats.dom );

				//

				window.addEventListener( 'resize', onWindowResize );

			}

			function onWindowResize() {

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

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

			}

			function animate() {

				render();
				stats.update();

			}

			function render() {

				const time = Date.now() * 0.01;

				object.rotation.y = object.rotation.z = 0.02 * time;

				const geometry = object.geometry;
				const attributes = geometry.attributes;

				for ( let i = 0; i < attributes.size.array.length; i ++ ) {

					if ( i < vertices1 ) {

						attributes.size.array[ i ] = Math.max( 0, 26 + 32 * Math.sin( 0.1 * i + 0.6 * time ) );

					}

				}

				attributes.size.needsUpdate = true;

				renderer.render( scene, camera );

			}

		</script>

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