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<!DOCTYPE html>
<html lang="en">
<head>
<title>three.js webgl - shader - curvature [ninja]</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> - curvature estimation of a geometry<br/>
by <a href="http://codercat.club" target="_blank" rel="noopener">CoderCat</a>
</div>
<script id="vertexShaderRaw" type="x-shader/x-vertex">
attribute float curvature;
varying float vCurvature;
void main() {
vec3 p = position;
vec4 modelViewPosition = modelViewMatrix * vec4( p , 1.0 );
gl_Position = projectionMatrix * modelViewPosition;
vCurvature = curvature;
}
</script>
<script id="fragmentShaderRaw" type="x-shader/x-fragment">
varying vec3 vViewPosition;
varying float vCurvature;
void main() {
gl_FragColor = vec4( vCurvature * 2.0, 0.0, 0.0, 1.0 );
}
</script>
<!-- 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 { GUI } from 'three/addons/libs/lil-gui.module.min.js';
import { OrbitControls } from 'three/addons/controls/OrbitControls.js';
import { OBJLoader } from 'three/addons/loaders/OBJLoader.js';
let camera, scene, renderer;
let ninjaMeshRaw, curvatureAttribute, bufferGeo;
init();
animate();
//returns average of elements in a dictionary
function average( dict ) {
let sum = 0;
let length = 0;
Object.keys( dict ).forEach( function ( key ) {
sum += dict[ key ];
length ++;
} );
return sum / length;
}
//clamp a number between min and max
function clamp( number, min, max ) {
return Math.max( min, Math.min( number, max ) );
}
//filter the curvature array to only show concave values
function filterConcave( curvature ) {
for ( let i = 0; i < curvature.length; i ++ ) {
curvature[ i ] = Math.abs( clamp( curvature[ i ], - 1, 0 ) );
}
}
//filter the curvature array to only show convex values
function filterConvex( curvature ) {
for ( let i = 0; i < curvature.length; i ++ ) {
curvature[ i ] = clamp( curvature[ i ], 0, 1 );
}
}
//filter the curvature array to show both the concave and convex values
function filterBoth( curvature ) {
for ( let i = 0; i < curvature.length; i ++ ) {
curvature[ i ] = Math.abs( curvature[ i ] );
}
}
//initialize the scene
function init() {
scene = new THREE.Scene();
camera = new THREE.PerspectiveCamera( 75, window.innerWidth / window.innerHeight, 0.1, 1000 );
camera.position.x = - 23;
camera.position.y = 2;
camera.position.z = 24;
renderer = new THREE.WebGLRenderer();
renderer.setSize( window.innerWidth, window.innerHeight );
renderer.autoClear = false;
document.body.appendChild( renderer.domElement );
const controls = new OrbitControls( camera, renderer.domElement );
controls.minDistance = 20;
controls.maxDistance = 100;
const loader = new OBJLoader();
//load the obj
loader.load( 'models/obj/ninja/ninjaHead_Low.obj', function ( object ) {
object.traverse( function ( child ) {
if ( child.isMesh ) {
bufferGeo = child.geometry;
bufferGeo.center();
const dict = {};
for ( let i = 0; i < bufferGeo.attributes.position.count; i += 3 ) {
//create a dictionary of every position, and its neighboring positions
const array = bufferGeo.attributes.position.array;
const normArray = bufferGeo.attributes.normal.array;
const posA = new THREE.Vector3( array[ 3 * i ], array[ 3 * i + 1 ], array[ 3 * i + 2 ] );
const posB = new THREE.Vector3( array[ 3 * ( i + 1 ) ], array[ 3 * ( i + 1 ) + 1 ], array[ 3 * ( i + 1 ) + 2 ] );
const posC = new THREE.Vector3( array[ 3 * ( i + 2 ) ], array[ 3 * ( i + 2 ) + 1 ], array[ 3 * ( i + 2 ) + 2 ] );
const normA = new THREE.Vector3( normArray[ 3 * i ], normArray[ 3 * i + 1 ], normArray[ 3 * i + 2 ] ).normalize();
const normB = new THREE.Vector3( normArray[ 3 * ( i + 1 ) ], normArray[ 3 * ( i + 1 ) + 1 ], normArray[ 3 * ( i + 1 ) + 2 ] ).normalize();
const normC = new THREE.Vector3( normArray[ 3 * ( i + 2 ) ], normArray[ 3 * ( i + 2 ) + 1 ], normArray[ 3 * ( i + 2 ) + 2 ] ).normalize();
const strA = posA.toArray().toString();
const strB = posB.toArray().toString();
const strC = posC.toArray().toString();
const posB_A = new THREE.Vector3().subVectors( posB, posA );
const posB_C = new THREE.Vector3().subVectors( posB, posC );
const posC_A = new THREE.Vector3().subVectors( posC, posA );
const b2a = normB.dot( posB_A.normalize() );
const b2c = normB.dot( posB_C.normalize() );
const c2a = normC.dot( posC_A.normalize() );
const a2b = - normA.dot( posB_A.normalize() );
const c2b = - normC.dot( posB_C.normalize() );
const a2c = - normA.dot( posC_A.normalize() );
if ( dict[ strA ] === undefined ) {
dict[ strA ] = {};
}
if ( dict[ strB ] === undefined ) {
dict[ strB ] = {};
}
if ( dict[ strC ] === undefined ) {
dict[ strC ] = {};
}
dict[ strA ][ strB ] = a2b;
dict[ strA ][ strC ] = a2c;
dict[ strB ][ strA ] = b2a;
dict[ strB ][ strC ] = b2c;
dict[ strC ][ strA ] = c2a;
dict[ strC ][ strB ] = c2b;
}
let curvatureDict = {};
let min = 10, max = 0;
Object.keys( dict ).forEach( function ( key ) {
curvatureDict[ key ] = average( dict[ key ] );
} );
//smoothing
const smoothCurvatureDict = Object.create( curvatureDict );
Object.keys( dict ).forEach( function ( key ) {
let count = 0;
let sum = 0;
Object.keys( dict[ key ] ).forEach( function ( key2 ) {
sum += smoothCurvatureDict[ key2 ];
count ++;
} );
smoothCurvatureDict[ key ] = sum / count;
} );
curvatureDict = smoothCurvatureDict;
// fit values to 0 and 1
Object.keys( curvatureDict ).forEach( function ( key ) {
const val = Math.abs( curvatureDict[ key ] );
if ( val < min ) min = val;
if ( val > max ) max = val;
} );
const range = ( max - min );
Object.keys( curvatureDict ).forEach( function ( key ) {
const val = Math.abs( curvatureDict[ key ] );
if ( curvatureDict[ key ] < 0 ) {
curvatureDict[ key ] = ( min - val ) / range;
} else {
curvatureDict[ key ] = ( val - min ) / range;
}
} );
curvatureAttribute = new Float32Array( bufferGeo.attributes.position.count );
for ( let i = 0; i < bufferGeo.attributes.position.count; i ++ ) {
const array = bufferGeo.attributes.position.array;
const pos = new THREE.Vector3( array[ 3 * i ], array[ 3 * i + 1 ], array[ 3 * i + 2 ] );
const str = pos.toArray().toString();
curvatureAttribute[ i ] = curvatureDict[ str ];
}
bufferGeo.setAttribute( 'curvature', new THREE.BufferAttribute( curvatureAttribute, 1 ) );
//starting filter is to show both concave and convex
const curvatureFiltered = new Float32Array( curvatureAttribute );
filterBoth( curvatureFiltered );
const materialRaw = new THREE.ShaderMaterial( {
vertexShader: document.getElementById( 'vertexShaderRaw' ).textContent,
fragmentShader: document.getElementById( 'fragmentShaderRaw' ).textContent
} );
ninjaMeshRaw = new THREE.Mesh( bufferGeo, materialRaw );
}
} );
scene.add( ninjaMeshRaw );
} );
//init GUI
const params = {
filterConvex: function () {
const curvatureFiltered = new Float32Array( curvatureAttribute );
filterConvex( curvatureFiltered );
bufferGeo.attributes.curvature.array = curvatureFiltered;
bufferGeo.attributes.curvature.needsUpdate = true;
},
filterConcave: function () {
const curvatureFiltered = new Float32Array( curvatureAttribute );
filterConcave( curvatureFiltered );
bufferGeo.attributes.curvature.array = curvatureFiltered;
bufferGeo.attributes.curvature.needsUpdate = true;
},
filterBoth: function () {
const curvatureFiltered = new Float32Array( curvatureAttribute );
filterBoth( curvatureFiltered );
bufferGeo.attributes.curvature.array = curvatureFiltered;
bufferGeo.attributes.curvature.needsUpdate = true;
}
};
const gui = new GUI( { title: 'Topology' } );
gui.add( params, 'filterConvex' );
gui.add( params, 'filterConcave' );
gui.add( params, 'filterBoth' );
onWindowResize();
window.addEventListener( 'resize', onWindowResize );
}
function onWindowResize() {
renderer.setSize( window.innerWidth, window.innerHeight );
camera.aspect = window.innerWidth / window.innerHeight;
camera.updateProjectionMatrix();
}
function animate() {
requestAnimationFrame( animate );
render();
}
function render() {
renderer.render( scene, camera );
}
</script>
</body>
</html>