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<!DOCTYPE html>
<html lang="en">
<head>
<title>three.js webgl - buffergeometry - lines - indexed</title>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0">
<link type="text/css" rel="stylesheet" href="main.css">
</head>
<body>
<div id="container"></div>
<div id="info"><a href="https://threejs.org" target="_blank" rel="noopener">three.js</a> webgl - buffergeometry - lines - indexed</div>
<!-- Import maps polyfill -->
<!-- Remove this when import maps will be widely supported -->
<script async src="https://unpkg.com/es-module-shims@1.3.6/dist/es-module-shims.js"></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';
let container, stats;
let camera, scene, renderer;
let parent_node;
init();
animate();
function init() {
container = document.getElementById( 'container' );
camera = new THREE.PerspectiveCamera( 27, window.innerWidth / window.innerHeight, 1, 10000 );
camera.position.z = 9000;
scene = new THREE.Scene();
const geometry = new THREE.BufferGeometry();
const material = new THREE.LineBasicMaterial( { vertexColors: true } );
const indices = [];
const positions = [];
const colors = [];
let next_positions_index = 0;
//
const iteration_count = 4;
const rangle = 60 * Math.PI / 180.0;
function add_vertex( v ) {
if ( next_positions_index == 0xffff ) console.error( 'Too many points.' );
positions.push( v.x, v.y, v.z );
colors.push( Math.random() * 0.5 + 0.5, Math.random() * 0.5 + 0.5, 1 );
return next_positions_index ++;
}
// simple Koch curve
function snowflake_iteration( p0, p4, depth ) {
if ( -- depth < 0 ) {
const i = next_positions_index - 1; // p0 already there
add_vertex( p4 );
indices.push( i, i + 1 );
return;
}
const v = p4.clone().sub( p0 );
const v_tier = v.clone().multiplyScalar( 1 / 3 );
const p1 = p0.clone().add( v_tier );
const angle = Math.atan2( v.y, v.x ) + rangle;
const length = v_tier.length();
const p2 = p1.clone();
p2.x += Math.cos( angle ) * length;
p2.y += Math.sin( angle ) * length;
const p3 = p0.clone().add( v_tier ).add( v_tier );
snowflake_iteration( p0, p1, depth );
snowflake_iteration( p1, p2, depth );
snowflake_iteration( p2, p3, depth );
snowflake_iteration( p3, p4, depth );
}
function snowflake( points, loop, x_offset ) {
for ( let iteration = 0; iteration != iteration_count; iteration ++ ) {
add_vertex( points[ 0 ] );
for ( let p_index = 0, p_count = points.length - 1; p_index != p_count; p_index ++ ) {
snowflake_iteration( points[ p_index ], points[ p_index + 1 ], iteration );
}
if ( loop ) snowflake_iteration( points[ points.length - 1 ], points[ 0 ], iteration );
// translate input curve for next iteration
for ( let p_index = 0, p_count = points.length; p_index != p_count; p_index ++ ) {
points[ p_index ].x += x_offset;
}
}
}
let y = 0;
snowflake(
[
new THREE.Vector3( 0, y, 0 ),
new THREE.Vector3( 500, y, 0 )
],
false, 600
);
y += 600;
snowflake(
[
new THREE.Vector3( 0, y, 0 ),
new THREE.Vector3( 250, y + 400, 0 ),
new THREE.Vector3( 500, y, 0 )
],
true, 600
);
y += 600;
snowflake(
[
new THREE.Vector3( 0, y, 0 ),
new THREE.Vector3( 500, y, 0 ),
new THREE.Vector3( 500, y + 500, 0 ),
new THREE.Vector3( 0, y + 500, 0 )
],
true, 600
);
y += 1000;
snowflake(
[
new THREE.Vector3( 250, y, 0 ),
new THREE.Vector3( 500, y, 0 ),
new THREE.Vector3( 250, y, 0 ),
new THREE.Vector3( 250, y + 250, 0 ),
new THREE.Vector3( 250, y, 0 ),
new THREE.Vector3( 0, y, 0 ),
new THREE.Vector3( 250, y, 0 ),
new THREE.Vector3( 250, y - 250, 0 ),
new THREE.Vector3( 250, y, 0 )
],
false, 600
);
//
geometry.setIndex( indices );
geometry.setAttribute( 'position', new THREE.Float32BufferAttribute( positions, 3 ) );
geometry.setAttribute( 'color', new THREE.Float32BufferAttribute( colors, 3 ) );
geometry.computeBoundingSphere();
const lineSegments = new THREE.LineSegments( geometry, material );
lineSegments.position.x -= 1200;
lineSegments.position.y -= 1200;
parent_node = new THREE.Object3D();
parent_node.add( lineSegments );
scene.add( parent_node );
renderer = new THREE.WebGLRenderer();
renderer.setPixelRatio( window.devicePixelRatio );
renderer.setSize( window.innerWidth, window.innerHeight );
renderer.outputEncoding = THREE.sRGBEncoding;
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() {
requestAnimationFrame( animate );
render();
stats.update();
}
function render() {
const time = Date.now() * 0.001;
parent_node.rotation.z = time * 0.5;
renderer.render( scene, camera );
}
</script>
</body>
</html>